continuous infusion of bupivacaine for analgesia during labor
TRANSCRIPT
Thursda;, April 2 8:00 - 8:15 a.m.
CONTINUOUS INFUSION OF BUPIVACAINE FOR ANALGESIA DURING LABOR
Teresa Valencia, Nancy B. Kenepp, Brett B. Gutsche Temple University Hospital, Hospital of the University of Pennsylvania
Continuous infusion of a local anesthetic solution into the epidural
space for analgesia during labor provides a steady dermatome level of analgesia and avoids the problems associated with the need for multiple reinjections. Several local anesthetic agents have been used success- fully with this technique. A study reported by us at the SOAP meeting in 1980 found that with Z-chloroprocaine, a large volume of a dilute so- lution was more effective than an equal milligram dose of a more concen- trated solution. The hydrogen ion concentration difference in the anes-
thetic solutions, although at first glance an attractive explanation, was not a likely factor since the pH differences were small, and normal saline, the diluent, is acidic and increased the total hydrogen ion load in the more dilute solution. This prospective study was designed to determine whether a similar effect occurred with bupivacaine.
The protocol was approved by the Committee on Studies Involving Man and informed consent was obtained from uncomplicated term patients. Epidural catheters were uniformly positioned in the L interspace and patients were nursed in the semi-supine position with36ft uterine dis- placement. The patients were assigened to one of four groups randomly. All received a 2 cc test dose of 0.25% bupivacaine followed by a loading dose of 8 cc of 0.25% bupivacaine. For the next 135 minutes the patients received 20 mg per hour of 0.5, 0.25 or 0.125% bupivacaine (Group A, B and C respectively) or 10 mg per hour of 0.125% bupivacaine (Group D), unless inadequate analgesia or delivery dictated termination of the study. Pain and temperature sensation, motor block and subjective analgesia were evaluated at 20 minute intervals thereafter. Statistical analysis was carried out by analysis of the variance and the chi-square test for pro- bability of a difference.'
Initial results indicate an effect similar to the that seen with 2-chloro- procaine is present with bupivacaine. Twenty mg of 0.125% bupivacaine appears to provide a better block than 20 mg of 0.5% bupivacaine; the number of dermatomes block to temperature fell by 3 during the infusion of 0.5% bupivacaine, whereas it rose by 4 when 0.125% bupivacaine was in- fused. Analgesia was satisfactory initially in all groups, although the block was patchy in several patients; analgesia declined in the 0.5% bupivacaine group. Notor strength depended on the quality of the block. In those patients with a large number of dermatomes blocked, motor strength decreased. To date tachyphylaxis has not been demonstrated. The study is in progress and more complete data will be available at the time of presentation.
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Thursday, April 2 8:15 - 8:30 a.m.
CONTINUOUS EPIDURAL INFUSION FOR LABOR AND DELIVERY
Stephen Kelly, M.D., John C. Hargrove, M.D., Virginia Williams, M.D., Depart- ments of Anesthesiology, University of Washington School of Medicine and The Virginia Mason Clinic, Seattle, Washington.
Maintenance of adequate analgesia for the laboring parturient in a busy obstetrical service may place demands on anesthesia personnel which are not easily met. The safety and efficacy of continuous infusion segmental epidural analgesia using weak anesthetic concentrations were evaluated during labor and delivery in the obstetrical population at the University of Washington. The therapeutic goal was to eliminate periods of inadequate pain relief and to main- tain segmental analgesia without motor blockade during labor.
Forty consenting parturients who were suitable candidates for neuraxixs block were given epidural analgesia during the active stage of labor after placement of both lumbar and caudal catheters. After initial test and therapeutic doses of 3 and 4 cc of 0.25% bupivacaine, patients were monitored for 15 minutes for changes in vital signs, fetal heart rate (FHR) uterine activity (UA), and pres- ence of analgesia. In the absence of adverse sequellae from these initial doses, an infusion of 0.125% bupivacaine in 0.9% NaCl, without preservative or vasocon- strictor was administered at an initial rate of 12 cc/hr via infusion pump. Vi- tal signs, FHR, UA, subjective (per parturient) and objective (per MD or RN) scores for motor and sensory block levels were noted every 30 minutes during the infusion. If analgesia declined to inadequate levels during labor, the lumbar catheter was rebolused with 0.25% bupivacaine. The caudal catheter was injected at delivery to provide perineal muscle relaxation.
In the subjective evaluation from the forty patients in whom the infusion was maintained for two hours or more (range 2-21 hours), 95% had mean sensory scores indicating excellent analgesia. The remaining 5% rated the technique as marginal in some respect. Physician and nursing assessments closely approxi- mated patient ratings. Significant motor block existed in only 5% of patients. Approximately 75% needed another lumbar bolus at some time during labor. The caudal catheter was used in 75% of patients, though we intended to use if for perineal relaxation .in all patients. There was no increased incidence of mal- presentation, operative delivery, or neonatal depression over that of patients receiving double catheter epidurals with bolus injections only, and there was no increased incidence in maternal or fetal drug toxicity apparent clinically.
Results from this pilot group of patients indicate that a technique of continuous epidural infusion of weak concentrations of local anesthetics will be beneficial to both parturients and to those who deliver anesthesia. Anal- gesia can be maintained at an acceptable segmental level by varying the rate of infusion while eliminating dramatic changes in maternal vital signs, FUR and UA which are often seen with bolus injections. Nursing personnel can easi- ly learn to monitor the levels of analgesia, and since they are with the pa- tient almost constantly, become quite proficient at noting small changes there- in. Although no adverse neonatal sequellae were seen in this group of patients, a larger study with formal, detailed neonatal follow-up is being conducted at this time.
Thursday. April 2 8:30 - 8:45 a.m.
2-D E - NEW APPFUXCH M 0I.D PRXLE%S. Fci&ard W.~~,MartanL.~,Mi~lSegall,AlanE.Sh~~~, andLarryS.Jahnsgard,DepartruentofNeaMtology,children'sHospital andHealthCenter,SanDiego,California.
Fourhmdzedtwzntyheadscanswerecbtainedfranohehuhdred fortyselectedinfantsweighing 0.53 to 7kilcgrams, gestaticmal age 25 weks to 1 year postnatal, using the Mark III A.T.L. 900 scanner withaSMgahertztransducer, Sweeping views in threeplanes,corcml, sagittal,andharizantal,~obtained,givingatri~iondl axqmsiteof theheadtoevaluateventricular size anddegmeof neonatal intracranial hemxrhage (ICH); i.e., s&epehdyml hmxxhage (SEH),SEZ=I withmtricularsxtension UVH),andSEHwithfurtherextensicminto the brain parenchym (BPH). Va.ryingstqesandaxbinationsofSEH, IVH, and BPH were detected and their serial progression evaluated. Ventxiculardilataticm franIVH, mningitis,andviralinfectionswas also serially follcwed, both before and after ventricular perimeal shunt placsfmt. Follm-up studies post-V-P shunt were particularly helpful inevaluatingventricular size, tube location, andshunt function. Theprocedurerequiresmininnrm~gandcanbeperfo~d inminutes atthebedside eliminating transfer of seriously ill infants to X-ray. Ihequalityof the pictures in addition to the advantageof mltiple views in three planes, and the cost effectiveness, makes the 2-DechcermQmlogramsuperior to thecawentionalmnputerized tam- graphy scan in this age group. Serial slides ard/or videotapes of selectedcaseswillbepresentad.
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Thursday, April 2 8:45 - 9:OO a.m.
KINETICS OF LOCAL ANESTHETIC DRUGS IN THE MATERNAL/FETAL UNIT
R. L. Kennedy, M.D., H. de Sousa, M.D., J. U. Bell, Ph.D., D. M. Doshi, M.D., R. P. Miller, Ph.D., D. L. Heald, M.S., M. J. Kennedy, B.S., Y. David, M.S. Departments of Anesthesiology, Pharmacy, and Pharmacology and Toxicology, West Virginia University Medical Center, Morgantown, West Virginia.
Studies of placenta transfer are based on evaluation of fetal blood concentration following maternal drug administration. These studies do not indicate the amount of drug passing to the fetus that produces these fetal blood concentrations.
In order to elucidate the distribution kinetics of local anesthetics across the placenta, we are using chronically prepared ewes of 120-130 days gestation. An electromagnetic flow probe is placed around the common umbilical artery, and sampling catheters are positioned in the fetal abdominal aorta (FA) comnon umbilical vein (UV), fetal bladder 3ia the urachus, and in a maternal artery (MA).
On the third post-operative day, local anesthetic is infused intravenously at a constant rate into the mother over a one hour period. of lidocaine or 3 mg/kg of bupivicaine.
We use 7 mglkq Simultaneous samples are drawn from
FA, UV and MA every 5 minutes for 45 minutes, then every 15 minutes to two hours, then every 60 minutes thereafter to 5 hours. Blood gases are determined from each site and fetal urine is collected every hour. Local anesthetic blood concentration is determined using high pressure liquid chromatography. Continuous quantitative placental transfer fs determined by integrating the FA - UV difference with respect to flow and time.
We have found that when 7.0 mg/kg of lidocaine is infused maternally, the 'fetal concentration at the end of drug infusion reaches 1.7 + 0.5 S.D. with 2.1 + 1.5 mg/kq (SD) (N=4) remaining after 5 hours. For example, when
mg/kg
one 61 kg ewe was given 427 mg of lidocaine the 5.0 kg fetus retained 10.4 mg after 60 minutes, with 10.3 mg remaining after 5 hours, even thouqh FA drug levels fell from 1;2 ug/ml to 0.07 ug/ml in that time. Thus there is no significant placental clearance of lldocaine, despite low maternal blood levels.
With bupivfcaine however, it appears that a mean concentration of 0.25 mg/kg (N=2) is acheived in the fetus after infusing a 3 mq/kg dose, with only 0.13 mo!kg remaining after five hours. This clearance is against a concentration gradient.
Data concerning etidocaine and differential maternal/fetal serum protein binding will also be presented.
Thursday, Apr i I 2 9:oo - 9:15 a.m.
MATERNAL, FETAL AND NEONATAL DISPOSITION
OF BUPIVACAINE AND PPX
Kuhnert, B.R., Ph.D., Kuhnert, P.M., Ph.D., Gross, T.L., M.D., Stitts, J.M., B.S. Perinatal Clinical Research Center, Case Western Reserve University, 3395 Scranton Road, Cleveland, Ohio, 44109.
It is well known that the concentration of bupivacaine in umbilical cord blood at birth is low compared to the concentration in maternal blood. It is not clear whether this low fetal/maternal ratio (F/M) is due to decreased placental transfer or increased uptake by fetal tissues. The purpose of this study was to clarify this issue by studying the disposition of bupivacaine and its metabolite 2,6-pipecolylxylidine (PPX) in mother, fetus and neonate following epidural anesthesia. The study population included 13 parturients who were delivered by Cesarean section and their infants. GC-MS was used to determine bupivacaine and its PPX in maternal, fetal and neonatal body fluids. The results indicate several points: First, that bupivacaine and PPX remain detectable in neonatal blood for at least 3 days (Figure 1). Second, that plasma levels of PPX decrease more slowly in mother and neonatal than bupiva- Caine. Also, both mother and neonate excrete primarily PPX in urine, but a
. higher percentage of unchanged bupivacaine is excreted by the neonate. Finally, urinary excretion of PPX by the neonate remains relatively constant during the first 48 hours of life; in contrast, the mother excretes the highest amount of PPX between 12-24 hours postpartum. The persistence of bupivacaine and PPX in neonatal body fluids suggest that the low F/M ratio of bupivacaine at birth is due to considerable uptake of bupivacaine by fetal tissues and is not due to diminished placental transfer.
(Supported in part by USPHS NIH Grants #5MOl-RR-00210, lROl-HD-13359, and the Cuyahoga County Hospital Foundation)
DISAPPEARANCE OF EUPlVACAlNE AND PPX FROM NEONATAL
PLASMA FOLLOWING MATERNAL EPIOURAL ANESTHESIA
Figure 1
Thursday, April 2 q:15 - lo:oo a.m.
ANNUAL REVIEW OF NEONATOLOGY
Louis Gluck, M.D.
1. Jacob, J., Gluck, L., DiSessa, T., Edwards, D., Kulovich, M.V., Kurlinski, J., Merritt, T.A. and Friedman, W.F.: The contribution of PDA in the neonate with severe RDS. J. Pediatr. 96:79-87, 1980.
Thursday, April 2 lo:30 - lo:45 a.m.
THE EFFECTS OF REDUCTION OF UTERINE BLOOD FLOW ON THE FETUS IN THE CHRONIC- ALLY PREPARED SHEEP. H. Yaffe, M. Katz, and J.T. Parer. Department of Obstet., Gynec., and Reprod. Sci., and Cardiovascular Research Institute. University of California, San Francisco.
An inflatable plastic occluder was placed around the common portion of the uterine artery in sheep of approximately 120 days gestation. An electromagnetic blood flow transducer was placed on the branch of the uterine artery supplying the pregnant horn. Inflation of the occluder resulted in a stepwise and measureable reduction in uterine blood flow between 25 and 75% of normal.
Catheters were placed in the fetal carotid artery, jugular vein, femoral artery, femoral vein, and amniotic cavity. At least two days after surgery, studies were done on the sheep while it was standing quietly in a familiar laboratory.
Ten minutes after occlusion of the uterine arterial blood flow by the predetermined amount, blood samples were taken from the fetus. In two animals, regional distribution of blood flow in the fetus by the radio- active microsphere technique was also measured. The Table illustrates the values of acid-base and oxygenation in femoral arterial blood 10 minutes after occlusion by the stated nominal amount.
Degree of pH Occlusion
PO2 O2 sat. PC02 FHR FABP
mm Hg % n Hg bpm mm Hg
Control 7.42kO.05 27.021.5 63.4t3.5 4o.ai2.2 Ia3ki5 47+4
25%(4) 7.37kO.01 20.4k4.5 51.5k6.5 43.322.6 i72+ia 46t6
50%(7) 7.37kO.02 18.7+3.8 35.4i9.4 47.1k5.2 177?15 4928
75%(6) 7.36kO.05 13.7i2.4 26.429.7 50.0i2.2 150+60 51+5
(n); -+SD
With progressive degrees of uterine artery occlusion, there was pro- gressive hypoxaemia and hypercarbia, and the development of mild acidosis, exclusively respiratory. This was associated with an increase in fetal arterial blood pressure and a moderate bradycardia.
Blood flow to the placenta, brain, and heart increased with occlusions up to 50% of uterine blood flow, but decreased at 75% of control UBF. Gut and carcase blood flow decreased with occlusion up to 50% of control UBF but increased at 75% of control UBF.
This a valid model for studvina controlled, deliberately imposed redistribution of fetal blood flow fetal asphyxia. These results s;gg&t
to vital organs up to 50% reduction of pensatory mechanisms at 75% of UBF, as able redistribution.
UBF, and breakdown of these com- measured by reversal of the favor-
(Supported by NIH grant HD 13764)
Thursday, April 2 10:45 - ll:OO a.m.
Title: Localization of Airway Dilation in Pregnancy
Authors: Ying-Kan Tien, M.D. and Gail Little'ohn,M.D., Department of 9\
Anesthesiology, U. of Oregon Health Sciences Center, Portland, OR
It has been reported that pregnancy is associated with a large re-
duction in airway resistance. To see if this bronchodilation occurs pre-
dominantly at the large airways or the small airways (diameter 5 2 mm), we
compared the effect of varying gas density on the maximum expiratory flow
volume relationship, between women in late pregnancy and nonpregnant women.
By using a wedge spirometer and a storage oscilloscope, maximum ex-
piratory flow volume curves were obtained, first during air breathing, and
then after replacement of the alveolar gas with a mixture of 60% helium and
20% oxygen tHeOpI, the mixture being only 35% as dense as air but about
equally viscous. The ratio of He02-flow over air-flow at the same per-
centage of vital capacity, called the density dependence, was calculated.
Seven young and healthy women have been studied to date. There appears
to be a substantial reduction in density dependence during late pregnancy
(see below). In the woman Who was studied prepartum and 6-wk postpartum
(broken lines), childbirth resulted in nearly equal increases in density
dependence at all volumes shown. The physiological and clinical significance
of this finding will be discussed.
We feel that these data, though
limited, indicate a predominant large
airway dilation during pregnancy.
Thursday, April 2 ll:oo - 11:15 a.m.
HYPOXIC PDLMONARY HYPERTENSION - PROPOSED ROLE OF PLATBLETS. M.Segall, B. Coetzman, S. DeNardo, and S. Bennett, Depertment of Pediatrics, University of California, Davis, California.
Acute alveolar hypoxia is a potent eizhaulua producing the pulmonary pressor response. Circulatiug platelets have been implicated in the develop- ment of this response. This study was done to assess the effects of acute hypoxia induced pulmonary hypertension (PIIN) on platelet volume and number across the pulmonary circulation in 7 anesthetized newborn lambs. The animals were instrumented for measurement of pulmonary vascular resistance. All specimens for platelet studies were taken simultaneously from the aorta and pulmonary artery vhen breathing room air (control) and then at 5 and 30 minutes of 10% 02 breathing. Platelet counts were performed manually and platelet size was determined with a Model ZB coulter counter attached to a Coulter C-1000 Channelyser with X-Y recorder. In 3 lambs Cr51 labelling was used to determine the effect on platelet mass.
P.V.R. increased by almost 100% throughout the period of hypoxia. There vas a concomitant decrease in the size of platelets leaving the lung (~40-85) but no'change in their number. The number of platelets returning to the lung was reduced (p<O-05) but their sire distribution was unchanged. These observations were seen at both 5 and 30 minutes hypoxia. Cr51 label- ling of platelets showed a tendency to increased platelet mass when leaving the lung.
These findings serve as further evidence of a hypoxic-pulmonary-platelet interaction. The suggested mechanism is through the intrapulmonary release of vasoactive substances.
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Thursday, April 2 11:15 - 11:30 a.m.
IN-VITRO EVALUATION OF SODIUM CITRATE AS AN ANTACID Charles P. Gibbs, M.D., Donald F. Schmidt, M.D., Department of Anesthesiology, University of Florida College of Medicine
Antacids have been demonstrated to raise the pH of intragastric contents and are, therefore, felt by many to reduce the pathology produced by pulmonary aspiration of gastric contents. Gibbs et al demonstrated that a particulate antacid alone could produce significant pulmonary lesions in animals while a clear antacid (sodium citrate) was relatively benign. The effectiveness of sodium citrate as an antacid has not been established. Methods: First the volume of hydrochloric acid solution (HCl) at pH 0.8, 1.0 or 1.5 required to lower the pH of 30 cc of 0.3 M sodium citrate to 2.5 was determined. Next a comparison of acid neutralization among 0.3 M sodium citrate, Kolantyl-Gel and Camalox was performed. A mixture of one part antacid to ten parts 0.1 N HCl (pH 1.0) was measured for pH. Finally, a homogenous mixture of gastric aspirate adjusted to pH 1.5 with HCl was added in 100 ml aliquats to 30 ml of either 0.3 M sodium citrate or Kolantyl-Gel. The mixture was stirred continuously and pH measured after each 100 ml aliquat. Results: A volume of 140 ml of HCl at pH 0.8 was required to reduce the pH of 30 ml of 0.3 M sodium citrate to 2.5. Using HCl at pH 1.0, 255 ml were necessary. At pH 1.5, 750 ml of HCl were needed. In a 1:lO mixture of antacid to 0.1 N HCl, the Initial pH values were: sodium citrate 3.5, Kolantyl-Gel 3.5, and Camalox 5.7. The pH of mixtures containing Kolantyl-Gel and Camalox continued to rise with time. After 30 minutes, the pH of the Kolantyl-Gel/HCl mixture was 5.5 and that of Camalox/HCl was 6.7. When homogenous gastric aspirates were added to sodium citrate or Kolantyl-Gel, only 275 ml of aspirate were required to lower the PH of 30 ml sodium citrate to 2.5, whereas over 500 ml of aspirate were needed to produce the same decrease with 30 ml of Kolantyl-Gel. Discussion: This study demonstrates that in vitro sodium citrate uickly and effectively raises the pH of relatively-large volumes of acid 9 pH 1.5) gastric contents. The presence of partially digested food, however, appears to reduce sodium citrate's effectiveness.
Thursday, Aprii 2 11:30 - 11:45 a.m.
PL?K!ENTAL TRANSFER OF CIMETIDINE
Diane R. Biehl, M.D. and Mary Anne Colville, R.N.
Department of Anesthesia, University of Manitoba, Winnipeg, Canada
INTRODUCTION: One of the main hazards of general anesthesia in obstetrics is
the risk of maternal aspiration. Attemptsto neutralize gastric pH, clinically,
with oral antacids have not reduced maternal mortality, so other methods of
decreasing acidity have been sought. Cimstidine, a B2 receptor antagonist,
suppresses gastric acid production and has been suggested for use in obstetrical
patients, but transmission across the placenta has not been measured. The
following study was undertaken to examine tbe placental transfer of cimetidine.
METHOD I Twenty-four patients having elective repeat cesarean sections under
general anesthesia were studied after informed consent was obtained. Welve
patients in the control group received gelusil (30~~) 1 hour pre-operatively.
Twelve patients in the study group received cimetidine (300mg I.M.) 1 hour prior
to induction. General anesthesia was induced in the same manner in all patients.
At delivery 1Occ of maternal venous blood and 1Occ of umbilical venous blood
were obtained for analysis of cimetidine. After delivery of the infant, maternal
gastric samples for pH were obtained and gastric volume was measured by dye
dilution with propylethylglycolate. All infants were assessed at delivery by
1 and 5 minute apgar scores. Analysis of results was by Chi square (apgar scores)
and Student's "T" test for unpaired data (gastric pH and volume).
RESULTS: There were no significant differences& the 2 groups with regard to
maternal age and parity, neonatal weight, and gestational age. One infant in
the gelusil group and 2 infants in the cimetidine group had apgars of less than
7 at 1 minute; but all were 0, or better, by 5 minutes.
Mean maternal gastric pH was 6.12+1.28 in the cimetidine group and 5.4421.66 in
the qelusil group. There was no significant difference in the means of the 2
qrou~s but 2 pH samples in the gelusil group were less than 3.0 Maternal and
neonatal cimetidine levels and maternal gastric volumes will be rfported.
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Thursday, April 2 11:45 - 12:oo
NOON
A COMPARISON OF GELUSIL AND SODIUM CITRATE ON GASTRIC ACIDITY AND YOLUME
Abboud TK, M.D., Curtis JD, M.D., Earl S, C.R.N.A., Henriksen EH, M.D., Hughes SC, M.D., Levinson C, M.D., Shnider SM, M.D.
Department of Anesthesia, University of Southern California, Los Angeles, and Departments of Anesthesia, Obstetrics, Gynecology and Reproductive Sciences, University of California, San Francisco
Because of the risk of acid aspiration, an oral antacid is ro tinely given -Y to parturients prior to general anesthesia. However, Gibbs et al. demonstra- --
ted in dogs aspiration of particulate antacids can also cause pulmonary aspiration syndrome and residual fibrosis. As a result, there has been a gradual increase in the use of non-particulate antacids and especially 0.3 molar sodium citrate. Glycopyrrolate is also often administered.
s rior to
general anesthesia to reduce gastric volume and raise gastric pH. We compared administration of sodium citrate and glycopyrrolate with admini- stration of Gelusil and glycopyrrolate for their effectiveness to reduce gastric acidity and volume.
METHOD We studied 25 patients undergoing cesarean section with general anesthesia.
Approval was received from the Committee on Human Research, and each patient gave informed consent. Patients were randomly assigned to receive 30 ml of either Gelusil or 0.3 molar sodium citrate p.0. (both with 0.4 mg of intramuscular glycopyrrolate) at least 30 min. before induction of general anesthesia. All patients had a rapid induction with thiopental and succinylcholine and were intubated while cricoid pressure was applied. Anesthesia was maintained with 50% N20 and 0 with addition of low-dose halogenated hydrocarbon. After delivery of t he infant, an orogastric tube was placed. Gastric aspirate was obtained immediately after delivery and just prior to removal of the endotracheal tube. The volume and pH of each sample were measured, and ~1~11 0.J I( sod‘ results are as fol!ows: (II . 12, u clXt*c. [n . 13,
There were no statisti- ’ Z;c::t~~~~ tally significant differ- Iql* (da) ences between the two antacids. yiu (t ro) Mt 16
ht. ?I 1 IZ 20-Do
CONCLUSION 32 - IU
s-l* Sodium citrate (0.3 m) was 1 2
WI* 1 a
as effective as Gelusil in w (UIU)
raising gastric pH. However, gc* =’ 6.70 t 0.6 2.50 - 7.8, 6.10 * 0.1 6.14 t #.,
1.64 - 6.M 1.11 - ,.#
the high incidence of a high V01u [d) total gastric volume in both YU (: SD) U * II I7 t I9 26 * I I
groups indicates that the tilt*z.l wu (.I, ) - IS5 J - 70 s-ma - I ‘: * ::
usual maneuvers (i.e., rapid hM it WJ 65 t 47 tic*
.z t s6 I2 - 165
induction, application of 10 - 110
-
cricoid pressure, endotracheal intubation, and awake extubation) should still be used during general anesthesia for parturients.
REFERENCES I. Gibbs CP, et al. : Anesthesiology 53:3BO, 1979 2. Baraka A, et al.: Anesth - Analog 56:642, 1977
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Thursday, April 2 12:oo - 12:15 p.m.
Double Blind Comparison of Cimetidine (Tagamet (R) ) and Mylanta II(R) in respect
to SaEety and EfEect on Gastric Volume and Acidity in both Mother and Neonate
Robert Hodgkinson. M.D., Raymond Glassenberg, M.D., Dennis W. Coombs, M.D., Thomas H. Joyce, M.D., Gerard W. Ostheimer, M.D., from the Depts. of Anesthesiology of University of 'Texas at San Antonio, Northwestern University Dartmouth Medical School. University of Cincinnati and Harvard Medical School
One hundred healthy parturients scheduled for elective ccsarean section under general anesthesia gave written informed consent as individually approved by the Institutional Review Boards of the five participating centers. On the night prior to operation randomized coded material consisting of a tablet (cimetidine or placebo) and 30 ml of liquid (placebo or Mylanta II) was administered. One hour prior to anesthesia an i.m. injection (cimetidine or placebo) and 30 ml of liquid (placebo or Mylanta II) was administered. If the operation was delayed the patient received a further i.m. injection and dose of liquid every 4 hours. The only active premeditation received by any one patient was either cimetidine or Mylanta II.
The results of the study will be assessed by the following criteria:
1. Maternal gastric volume and acidity as aspirated by nasogastric tube immediately after induction of anesthesia and continuously collected in 15 minutes aliquots throughout anesthesia.
2. Any changes in laboratory values in samples taken before the first administration of medication and on the second and fourth post partum days. Laboratory evaluation included RBC, WBC (total 6 differential), platelet counts, serum bilirubin, alkaline phosphatase, SGOT, BUN and creatinine; chemical and microscopical urinalysis.
3. Any intoward events including changes in pulse, arterial pressure, ECG during anesthesia.
4. An assignment of the-patient on days 2 and 4 into 5 categories: (A. PEEP required, B..pathology of chest requiring film, C. Increased WBC and temperature, D. Increased WBC or temperature, E. Negative).
5. Blood samples for cimetidine levels taken from the maternal vein and the umbilical artery and vein at birth.
6. The Apgar Score on the babies at 1, 5,and IO minutes of age.
7. The neonatal gastric volume at birth and at 48 hours.
8. Neonatal Neurobehavior as assessed by the Early Neonatal Neurobehavioral Scale (ENNS) at 2 and 4 hours and 4 days after birth.
Detailed analysis of differences in maternal and neonatal gastric volume and acidity, the Apgar score and neonatal neurobehavior will be presented together with a summary of any significant changes found.
Friday, April 3 9:oo - a:15 a.m.
HYPOXEMIA DURING SELECTIVE BRONCHIAL INTUBATION AND UNILATEML LUNG VENTILATION. Morton Co&, R.W. Henderson, L.S. Johnsgard, A.E.Shumacher. The Children’s Hospital, San Diego,
Severe, progressive unilateral pulmonary interstitial cmphysema(PIF) has been successfully treated at a number of neonatal centers by selective bron- chial intubation (SBI) and continuous positive pressure ventilation (CPPV) of the contralateral lung. At Children’s Hospital, San Diego, WC have attempted SBI in 6 premature infants (mean birth weight 1340 gms) and have achieved fa- vorable results (i.e., survival with permanent resolution of the PIE) in all, thereby avoiding lobectomy or pneumonectomy. SBI was instituted at l-42 days of age because of a critically worsening condition and/or failure of conser- vative therapy. The right mainstem bronchus was intubated in 4 cases, the left in 2 cases. The infants were maintained on pancuronium for the duration of SBI (2-6 days). Because of ollr policy of long-term umbilical artery cathe- terization for chronic respiratory failure, and because of the availability of continuous oxygen monitoring via transcutaneous PO2 or the Shaw Oximetrix umbilical catheter, arterial blood gases could be monitored more closely dur- ing SBI than has been previously reported.
In 4 of 6 patients an immediate increase in hypoxemia occurred upon insti- tution of SBI, with virtual R+L shunt increasing from a mean of 36% to 60%. This occurred despite “radiologic success,” i.e., proper placement of the en- dotracheal tube in the mainstem bronchus, normal expansion of the ventilated lung, and atelectasis without PlE on the non-ventilated side. The increased hypoxemia persisted for 8 to 48 hours, ‘then resolved spontaneousl!f, except in one case, where SBI was discontinued after 48 hours because of continued need for an Fi02 of 1.0.
The sudden increase in R+L shunt after SBI is most likely due to increased pulmonary blood flow (PBF) to the non-ventilated (atelectatic) side, which may be related to the effect of unilateral CPPV upon the unsupported intra- alveolar blood vessels (pulmonary capillaries). During CPPV intraalveolar pressure may exceed pulmonary venous pressure (zone 2) or pulmonary arterial pressure (zone 1) during part or all of the respiratory cycle. This would favor PBF to unventilated areas (such as areas of atelectasis or consolida- tion), where alveolar pressure remains close to atmospheric pressure and be- low both pulmonary arterial and venous pressure (zone 3) throughout the res- piratory cycle. Thus CPPV could worsen the intrapulmonary K+L shunt bv prefe- rential redistribution of PBF to non-ventilated areas. Tn the 2 neonates whose hypoxemia did not worsen after SBI, one did not develop rapid atclec- tasis of the non-ventilated side, while the other suffered a tension pneumo- thorax on the non-ventilated side during the selective intubation, thus prob- ably inhibiting PBF to that lung.
Preferential PBF to non-ventilated.areas during bilateral CPPV has been recently documented by V/C, scan in 2 older children with acute respiratory failure in our ICU; in both cases the hypoxemia was successfullY treated by selective partial occlusion of PBF to the involved region using a Swan-Cana catheter.
Spontaneous improvement in r’,n 3 in 3 of the neonates despite continuing unilateral lung ventilation and contralateral atelectasis :;uggests tllat hy- poxic pulmonary vasocontriction, which normally would prevent preferential PBF to atelectatic areas, may be operative but delayed for hours or days.
SBI in selected cases can he life-saving. Transient increased hypoxemia may occur and does not preclude success. If the degree of hypoxemia is not l.ife-threatening, SRI can and should he continued.
Friday, April 3 8:15 - 8:30 a.m.
MATERNAL HAZARDS OF KETAMINE INDUCTION: A CESAREAN SECTION STUDY. W.D.R. Writer, M.B., Ch.B., F.M. James, III, M.D., D.M. Dewan, M.D., H.M. Floyd, M.D., T.D. Bogard, M.D., A.S. Wheeler, M.D. The Department of Anesthesia, Bowman Gray School of Medicine, Winston-Salem, N.C. 27103
Ketamine (1 mg/kg) has been recommended for induction of general anesthesia for Cesarean section. In this dosage, neo- natal Apgar scores and acid-base status compare favorably with thiopental (4 mg/kg) while neurobehavioral studies suggest advantages for ketamine. Although maternal psychotomimetic side effects appear to be dose dependent, studies of low dose regimes in obstetrics provide conflicting results. Undesirable pressor responses, dreaming and awareness may also accompany light anesthesia. We therefore decided to investigate a group of mothers requesting general anesthesia for Cesarean section to determine if detrimental maternal changes occur after induction with low dose ketamine.
METHODS: 4+& .- Twenty ASA 1 or 2 parturients without cardio- vascular disease, pregnancy induced hypertension or psychiatric illness received I.V. ketamine (0.8-l mg/kg) for induction, succinylcholine (1.5 mg/kg) to facilitate tracheal intubation and 66 percent nitrous oxide until delivery. We gave all mothers I.V. morphine sulphate (10 mg) following delivery and maintained anesthesia with 70 percent nitrous oxide and relax- ation with succinylcholine infusion (0.1 percent). We recorded pulse and blood pressure (Riva-Rocci technique) at 2 min. intervals until delivery. In recovery room patients were observed for nausea and vomiting, post operative hypertension and restlessness.
All patients were visited on the first post-partum day and questioned about operative recall and dreaming. Dreams and hallucinations were classified as 'dream like experiences' and we asked patients to describe them as pleasant or unpleasant.
RESULTS: Mean arterial pressure increased from 94t2 mm Hg to 115t3 mm Hg while pulse rate rose from 91+3 per min. to 109'4 per min. The increase in rate pressure product (RPP) from 11400t460 to 16060t680 (+41 percent) reflects the prominent pressor and chronotropic effects of this technique. RPPexceeded 20,000 in 4 cases (16 percent).
Eleven mothers reported dream like experiences (44 percent) of which 6 were hallucinatory. Six mothers (24 percent) des- cribed the psychotomimetic phenomena as unpleasant and expressed dissatisfaction with their anesthesia. We observedpost-operative restlessness (usually mild) in 11 mothers (44 percent). Nausea or vomiting occurred in 4 subjects (16 percent) and one patient experienced operative recall.
Although patient satisfaction was high (76 percent) we con- sider these results unsatisfactory. We conclude that ketamine cannot be recommended for 'routine' induction of anesthesia for Cesarean section. Maternal circulatory changes are potentially hazardous. Unpleasant dreams influence maternal fulfillment and may be undesirable in this psychologically vulnerable population.
15
Friday, April 3 8:30 - 8:45 a.m.
EFFECT OF HYPERMAGNESEMIA ON NEUROLOGIC SECTION OF OUBOWITZ EXAM. Patricia M. Huber, Deborah K -+ Rasch, C. Joan Richardson, Charles S. L'Hommedleu. University of Texas Medical Branch Hospitals, Department of Pediatrics, Galveston.
To study effect of hypermagnesemia on neurologic estimate of gestational age (EGA), 3 groups of neonates were identified: Group A - hypermagnesemic (HM) infants of magnesium sulfate (MS) treated pre-eclamptic mothers. Cord blood magnesium (CBM) was 4.2 + 0.7 mg/dl. Group B - non HM infants (CBM 1.5 + 0.2 mg/dl)
. of untreated pre-eclamtic mothers. Group C - contror infants (CBM 1.6 + 0.2 rng/dl) of normal, non MS treated mothers. Serial EGAs were done by method of Dubowitz, et al. Scores from neuro- logic section of the exam are given as mean + 1 S.D. EGA is given in weeks.
Group A Group B Group C-- -
n = 36 n = 18 n = 25 Age Score EGA Score EGA Score EGA
Birth 23.1+3.8 37-39 27.9+3.5 39-40.5 29.6t2.8 40-41.5 12 Hr. 27.7T3.2 39-40.5 31.771.7 40-41 31.4F2.3 40.5-42 24 Hr. 30.073.7 39-40.5 31.751.8 40-41 31.9T2.0 41-42 48 Hr. 31.2z2.5 40.5-42 31.52.1 40-41 32.23.6 41-42
EGAs of B & C did not significantly vary over 48 hrs. EGAs of A varied as much as 5 weeks. EGA, therefore, is unreliable by this method in HM infants whose mothers received MgSO in the first 48 hrs. Children born to mothers with pre-eclafipsia not treated with MgS04 showed no such effect.
Friday, April 3 a:45 - ~~00 a.m.
ISOXSUPRINE INDUCED PULMONARY EDEMA
Vivian S. Rambihar, M.D.; Ernest L.
Carl Nimrod, M.D.; Sydney 6. Effer,
John A. Cairns, M.D.
DURING PRETERM LABOR
Fallen, M.O.;
M.D. and
From the Divisions of Cardiology (Drs. Rambihar, Fallen
and Cairns) and Perinatal Medicine (Drs. Nimrod and Effer),
McMaster University Faculty of Health Sciences, Hamilton,
Ontario, Canada.
ABSTRACT
Isoxsuprine (ISOX) is a potent
effective in suppressing premature
with ISOX we identified seven (0.6%
either prepartum in five or immedia
uterine muscle relaxant and often
abor. Of 1276 cases requiring tocolysis
who developed acute pulmonary edema (PE)
ely following delivery in two. None had
co-existent heart disease. ISOX was given as an IV infusion (avg. 0.41 mg/min)
for 1.5 to 9.4 days with an average total dose of 1.8 gm. Four patients
received alcohol infusion which was discontinued 24 hr. before PE in all but
one patient. Four patients received steroids. To prevent ISOX induced
hypotension, all patients received IV fluids (avg. 3.57 L/day). There was an
average hemoglobin dcclinc of 1.3 gm/dl during ISOX infusion. The PE was raPid-
ly reversed with oxygen, bed rest and IV diuretics. Diqoxin was required in
three patients. This study indicates that intravenous ISOX and volume loading
can precipitate PE in about one-half per cent of otherwise healthy women durinq
preterm labor.
17
9:OO - 3:15 a‘.nl.
Maternal Pulmonary Edema Associated with Terbutaline and
Betamethasone Therapy: Hemodynamic Observations
Thomas J. Benedetti, J. Patrick O'Grady, John C. Hargrove, Mark Morton -._.
Department of Obstetrics and Gynecology and Anesthesiology, University of Washington a1
Department of Obstetrics and Gynecology and Internal Medicine, University of Oregon
The use of betamimetic drugs to inhibit premature labor and corticosteroids to accel- erate fetal pulmonary lung maturity is gaining widespread acceptance throughout the United States and Europe. The most serious maternal complication of this therapy has been the development of pulmonary edema. Previous reports have assumed that pulmonary edema was secondary to left ventricular failure resulting from increased left ventri- cular filling pressure. However, no published hemodynamic data is available in pre- viously normotensive patients to support this assumption. This preliminary report describes hemodynamic data in 2 patients with pulmonary edema after treatment with intravenous terbutaline and intramuscular betamethasone.
RESULTS: PATIENT #l
Mean Arterial Pulmonary Artery Cardiac Pressure (mmHg) Pressure (mnHg)
Pulmonary Artery Colloid Osmotic Wedge Press(mmHg) Output(L/M) Pressure (mmHg)
20/1U 11.2
PATIENT #2
Mean Arterial End Diastolic Ejection Fraction Pressure (mmHg) Volume (cc) (%)
Cardiac Output (L/M)
60 106 87 10.1
I
DISCUSSION:
These data would seem to exclude many possible etiologies of pulmonary edema in these patients. Betamimetic therapy is known to result in water retention and hemodilution. Betamethasone is known to have a weak mineralocorticoid effect. However, neither of the 2 patients had evidence of volume overload or left ventricular failure. lOmmHg, #Z-Ejection fraction=B7%).
(#l-PAW= A second mechanism for pulmonary edema could be
secondary to a substantial decrease in colloid osmotic pressure accompanied by a mod- erate increase in left ventricular filling pressure. However, in patient #l there is only a slight reduction in colloid osmotic pressure and the gradient between colloid osmotic pressure and the pulmonary artery wedge pressure is normal (8.3maHg). A third mechanism for pulmonary edema could be a transient postcapillary vasoconstriction. While the data on neither of these patients can eliminate this consideration this sit- uation is usually seen with massive increases in mean arterial pressure. Hypertension has not been reported as a complication of betamimetic therapy. The fourth mechanism for development of pulmonary edema is an increase in pulmonary capillary permeability. Hemodynamically this is associated with a high cardiac output and normal left ventri- cular function. These hemodynamic observations were demonstrated in both the patients with pulmonary edema. A transient increase in pulmonary capillary permeability appears to be the most likely etiology of pulmonary edema in this situation.
18
Friday, April 3 10:30 - 10:45 a.m.
RELAXATION OF UTERUS WITH AMYL NITRITE IN CASES OF MULTIPLE DELIVERIES AND BREECH PRESENTATION
Y. Donchin and S. Evron Department of Anesthesiology
Hadassah University Hospital, Jerusalem, Israel
Most experts advise general anesthesia for uterine relaxation if intrauterine manipulation is needed, like in internal version and extraction of a breech presentation or for the delivery of a second twin.
When general anesthesia is rapidly administered in emergency situations the incidence of morbidity, e.g., acid aspiration for the mother and de- pression of the fetus, is high.
Amy1 nitrite, among the oldest drugs used in medicine to provide relief from attacks of angina pectoris is a vasodepressor and it is a smooth muscle relaxant. It has a short but profound relaxing effect after inhalation. The effect of the drug can be obtained by placing a capsule in the rebreath- ing bag of the Magi11 circuit and then cracking it when required. Prior to using amyl nitrite the mother should be warned that she will smell a strong odour and experience a feeling of ilight headedness for a few minutes.
In this presentation we report on 5 women with twin delivery under epidural anesthesia in whom internal version and complete breech extraction were indicated in the second twin.
Short but deep uterine relaxation was achieved by inhalation of one ampule of the drug.
No adverse effect such as h'ypotension, fetal distress or postpartum hemorrhage were observed.
We highly recommend that amyl nitrite be readily availJpble to the anesthetist in the delivery room.
29
Friday, April 3 10:45 - ll:oo a.m.
OBSTETRIC PAIN RELIEF USING EPIOURAL MORPHINE
Peter Krasznai, M.D., Agnes Rappai, M.D., Oluremi Mamudu, M.D. Department of Obstetrics and Gynaecology
Peterfy Hospital, Budapest, Hungary
Epidural morphine (EM) administered successfully in the treatment of acute and chronic pain produced unsatisfactory results when used for obstetric pain relief. The aim of our research is to therefore determine whether it is worthwhile to use EM for obstetric pain relief and if so, in what circumstances.
Fourteen parturients - 9 primipara, 5 multipara, were given 2 mg each of morphine dissolved in 10 ml of 0.9% NaCl through a previously inserted epidural cannula.
Conditions for EM: Complication free pregnancy, spontaneous labour or labour induced at term, a single fetus and cephalic presentation. EM was given when the cervix was dilated 1 cm at the earliest and 6 cm at the latest.
The analgesic effect was ascertained by seeking the opinion of the parturient 30 minutes after the administration of the drug. The administra- tion of EM was not repeated during labour neither when pain relief was un- successful nor when the analgesia became insufficient. We then resorted to giving bupivacaine.
Results: In 4 cases we were able to achieve excellent pain relief throughout the period of labour. In 5 cases pain relief was achieved, but as labour progressed analgesia became insufficient. In the renaining 6 cases there wasn't adequate pain relief even 40 minutes after EM was given.
Our experiences show that: - 2 mg of EM can be given into the epidural space at any staqe of
labour without any mat.ernal or fetal complication arisinq; - 20-30 minutes is necessary for the achievement of analgesia. Analgesia
can therefore be ascertained as early as 30 minutes after the administration of the drug;
- the earlier in labour the drug was administered, the more frequently adequate analgesia was achieved;
- In partly successful or unsuccessful cases bupivacaine administered after EM enhanced its effect to give longer and better analgesia.
The likely explanation for our observations and conclusions will be discussed in our lecture.
30
Friday, April 3 11:00 - 11:15 a.m.
MATERYAL AND NEONATAL EFFECTS OF EPIDURAL MORPHINE FOR LABOR
Hughes SC, M.D., Rosen MA, M.D., Stefani SJ, M.D., Norton Ct. M.D., Abboud TK, M.D., Henriksen EH, M.D., Doan T, M.D., Johnson JL, Levinson G, M.D., Shnider SM, M.D.
Departments of Anesthesia, Obstetrics, Gynecology and Reproductive Sciences, University of California, San Francisco, and Department of Anesthesia, University of Southern California, Los Angeles
We wished to determine the efficacy, minimal effective dose, and potential hazards of preservative-free morphine that is injected into the epidural space to relieve the pain of labor.
METHOD We studied 40 healthy parturients at term who were in active labor. After
approval by the Committee on Human Research and informed consent were obtained, patients were randomly assigned to one of four groups according to the epidural anesthetic drug and dose they received: bupivacaine, n = 10) ; morphine, 2 mg (n = 9); morphine, 5 mg (n = 10); and morphine, In each group, a volume of 10 ml was injected through an epidural catheter. Neither the patient nor an evaluator knew which drug had been administered. Pain relief was assessed by the patient using a visual sensory analog scale, and by the evaluator using a four-point pain-intensity score and a five-point pain-relief score. Maternal respiratory rate, blood pressure and heart rate were also measured. The assessment of pain relief and measurements of vital signs were made just before injection of the drug, at IS-minute intervals for the first hour, and at hourly intervals thereafter until either delivery or until the patient requested additional medication for pain. A venous blood sample was obtained from the mother for blood gas analysis six hours after epidural injection. In all patients, correct placement of the epidural catheter w3s eventually confirmed by the administration of a local anesthetic.
Following delivery, the condition of the newborn was assessed using Apgar scores at 1 and 5 minutes, umbilical cord gas values, and the Neurologic and Adaptive Capacity Score at 2 and-24 hours of age.
RESULTS Neither the 2-mg nor S-mg doses of morphine produced satisfactory analgesia.
Only two of the patients in each of these groups were sufficiently comfortable at one hour after injection to remain in the study. On the other hand, 7.5 mg of morphine produced satisfactory analgesia in approximately half of the patients for up to three hours, and in 40 per cent for up to four hours after injection. Epidural administration of up to 7.5 mg of morphine produced no adverse effects on maternal ventilation, blood pressure or heart rate. These doses of narcotics also produced no deterimental effects on the clinical con- dition of the infant at birth, on the acid-base status of the fetus, or on the Neurologic and Adaptive Capacity Score. The incidence of adverse side effects was low. One woman who received 5 111.9 and two women who received 7.S mg had pruri t. i s , which was rcsolvcd(Q al 1 three instances wi th one intr;lmuscular dose of 25 or 50 mg Benadryl .
co;\(:I.l 1.s I o?i I’pidllrn! morphine 7.5 ro:? iri ?. volame of 111 ml (‘an r;;tfciy relit 1::’ the pain
of 1:2hor in npproximntcly 50 Per cent of patients. v<c~ t)c>l i eve Ihnt the opt imtim dosage and volumr of norphine irljoction is still to lx> tlc:tormincd. lie arc curwntly invcstixating tht: effects of :i 7.5-aq Jose that is ~l11utc~I in 3 ZO-ml volume.
31
Friday, April 3
11:15 - 11:30 a.m.
EFFECTS OF EPIDURAL MORPHINE ON UTERINE BLOOD FLOW AND MATERNAL AND FETAL CARDIOVASCULAR AND ACID-BASE STATUS IN THE PREGNANT EWE
Rosen MA, M.D., Hughes SC, M.D., Curtis JD, M.D., Norton M, M.D., Johnson JL, Jones MJ, Levinson G, M.D., Shnider SM, M.D.
Departments of Anesthesia, Obstetrics, Gynecology and Reproductive Sciences, University of California, San Francisco
Currently a number of investigators are studying the effects and safety of epidural opiates in the human parturient. However, to date, there have been no studies of the effects of these drugs on uterine blood flow or maternal and fetal cardiovascular and acid-base statuses. We are currently studying this new anesthetic technique in our chronic maternal-fetal sheep preparation.
METHOD Surgery was performed under general anesthesia in pregnant
ewes at 130 to 135 days gestation (normal gestation, 147-150 days). Polyvinyl catheters were inserted into both maternal femoral arteries, one maternal femoral vein, right carotid artery, right atrium and both fetal femoral arteries. A catheter was placed in the amniotic fluid, and an electromagnetic flow probe placed on a main branch of the uterine artery supplying the pregnant horn. All catheters and the probe were exteriorized and secured, and the animal was allowed to recover for 24 to 48 hours.
During a 30-minute control period, with the animal lying on her left side breathing supplemental oxygen through a face mask, we measured continuously maternal and fetal heart rate and blood pressure, maternal respiratory rate, and intra-amniotic and central venous pressures. At 0, 15, and 30 minutes, we measured maternal cardiac output using the cardiogreen method, and maternal and fetal arterial blood gases. The loss-of-resistance technique was used to enter the lumbar epidural space. A Teflon catheter was inserted and 20 mg of morphine in 20 ml of normal saline injected. Over the subsequent two-hour period, the same physiologic variables were measured as during the control period. Following the two-hour study period, a dose of 8 ml of 2% lido- Caine was injected through the epidural catheter to confirm correct placement.
RESULTS Preliminary results in five animals revealed that following
injection of morphine into the epidural space, no significant changes occurred in uterine blood flow, intra-amniotic pressure, maternal ventilation, cardiac output, stroke volume, total peripheral resistance or fetal well-being, as judged by arterial blood pressure, heart rate, and acid-base status.
32
Friday, April 3 11:30 - 11:45 a.m.
INTRATHECAL MORPHINE IN PREGNANT EWES. A. M. de Rosayro, M.D., V. Mullin,
M.D., M. L. Nahrwold, M.D., A. B. Hill, M.D., A. R. Tait, B.S. Department of
Anesthesiology, The University of Michigan Medical Center, Ann Arbor, MI 48109.
lntrathecal morphine may be useful in obstetric analgesia, but direct investigations
of its effects on fetaI well-being have not been reported. Therefore, four pregnant ewes
(120 d gestation) were anesthetized with methoxyflurane and a maternal femoral artery
(MA) and vein (MV) and a fetal femoral artery (FA) cannulated. The ewes were awakened
and the next day they received 2.5 mg of morphine (1 mg/mll intrathecally. Blood was
drawn for measurement of morphine levels (radioimmunoassay) and hlood gases at the
times and from the sites shown in the table. Maternal and fetal heart rates and blood
pressures were recorded continuously. Following intrathecal injection, morphine appeared
in blood from MV, MA and FA within 15 min. Maternal levels declined but fetal levels
remained nearly constant throughout the 7 hr period of study. Maternal and fetal heart
rates and blood pressures, MA blood gases, and PA PO2 were unchanged. However, FA pH
decreased 3 hr and FA PC02 increased 4 hr after intrathecal morphine. These alterations
persisted for 3 - 4 hr. Maternal blood levels of morphine were 10 fold less and fetal levels
were 50 fold less than those thought to provide analgesia. However, the significant fetal
acidosis observed in the study suggests extreme caution should be used regarding clinical
trials of intrathecal morphine for parturients.
FA pH
FA PCG, MORPHINE LEVELS trig/ml)
(torr) ’ MV MA FA
Control
15 min
1 hr
2 hr
3 hr
4 hr
5 hr
6 hr
7 hr
7.3fi + .03
7.36 + .93
7.34 + .03 -
7.32 + .04
7.30 + .04*
7.30 + .04*
7.30 + .n4*
7.29 + .n5* -
7.28 + .O6* -
*p 0.05 vs control
32 + 2 0 0 0
35 + 2 4.68 + 1.98 3.62 + .62 .33 + .I7 - __
36 + 1 4.34+ .09 3.16 + .32 .52 + .07 - -
38 + 1 3.21 + .92 2.31 + .25 .76 + .17
37 + 2 2.36 + - -49 1.35 + .30 .83 + .16 -
43 + 1* 1.92+ .43 1.40 + .21 .76 + .24 _.
42 + 2* 1.33 + - - .33 I.50 L .38 .73 + .22 _
44 + I* 1.13 + .26 1.21 + .30 .75 + .20 - - -
46 + 2* 1.06 + .72 + .25 - _ .23 1.23 _t .42
-__ -.---.- - .---------- -- -~.
All values means + SE -
77
Friday, April 3 11:45 - 12:oo
NOON
EPIDURAL MORPHINE FOR THE RELIEF OF POSTOPERATIVE PAIN AFTER CESAREAN SECTION
Hughes SC, M.D., Rosen MA, M.D., Norton M, M.D., Curtis JD, M.D., Dailey PA, M.D., Stefani SJ, M.D., Abboud TK, M.D., Henriksen EH, M.D. Levinson Ci,m., Shnider SM. M.D.
Departments of Anesthesia, Obstetrics, Gynecology and Reproductive Sciences, University of California, San Francisco, and Department of Anesthesia, University of Southern California, Los Angeles
Epidural morphine producing prolonged analgesia without sedation may be advantageous for the post-par-turn patient, in whom there are considerations of maternal-infant bonding and breast feeding. We are studying the cffect- iveness, dose requirement, and safety of epidural morphine for relief of postoperative pain after cesarean section.
METHOD Approval of the Committee on Human
m-&lum caorw sulia:~ R1*l Gth k+v
Research and informed consent were loo-
obtained. We studied postoperative analgesia in healthy patients under- going cesarean section who had received epidural anesthesia. catheters were left in place following
ants remd Patients were
assigned to receive one of four analgesic medications: 2 mg, 5 7.5 mg of epidural morphine in a 10 ml volume of saline or adminstration of -7s-
7.5 mg of intramuscular morphine (the control group). Patients were unaware
-loaL,. I. I 0 H I 2 3 4‘6 6%
of the amount of morphine given, and an TIYE Itwan@)
evaluator was unaware of either-technique or dose. Pain relief was assessed by the patient using a visual sensory analog, and by the evaluator using a four-point pain intensity score and a five-point pain relief score. Maternal respiratory rate, blood pressure and heart rate were also measured. A venous sample was obtained from the mother for blood gas analysis just before injection and at six hours after injection.
RESULTS To date we have studied 22 patients. Our results demonstrate that both the
S-mg and 7.5-mg doses of epidural morphine give excellent pain relief that has an onset of 15 to 30 minutes (figure). In both groups, the first request For additional pain medication after the initial injection ocurrctl at 19.5 hours (mean). the range being IS-21 hours in the 5-mg group and lo-29 hours in the 7.5-mg group. The 2-mg dose provided inadequate pain relief; most patients requested systemic analgesia at one hour. The control group (7.5 mg of IM morphine) experienced adequate analgesia within 30 minutes, al though pain relief lasted only two hours. Respiratory depression did not occur in any patient, as judged by respiratory rate measured up to 24 holtrs, anti by ~cnous blood gases at six hours after injection. Pruritis occurred frequently
’ “YA, was rapidly relieved by intramuscular injection of 25 to 50 mg of Renndryl . CONCc.US IO?1 Roth thex-mg and 7.5-mg doses of epidural morphine were highly cffccti1.e
in providing safe and long-lasting relief of postoperative pain aftcr cesarcan section. The 2-mg dose was inadequate.
Friday, April 3 I:30 - 1:45 p.m.
CPK and Its Isoenzymes as an Indicator of Abnormal Fetal Heart Rate Patterns S. Combs, H. Harris and R. Caldwell. The Newborn Center and Dept. of Pediatrics and Obstetrics, Methodist Hospital of Indiana.
Increased creatine phosphokinase (CPK) and its isoenzymes reflect damage to cells caused by ischemia, hypoxia, trauma and metabolic disorders. CPKI is found mainly in brain tissue, CPK2 in heart, and CPK3 in muscle. This study evaluated intrauterine fetal heart rate patterns (FHR) and CPK levels from venous blood drawn from neonates between 16 and 24 hours after birth in rela- tion to several other birth parameters.
Nineteen infants with normal FHR tracings were used as controls. Eleven infants had mild variable decelerations. Seven infants had moderate variable decelerations and five had severe; these two classes were grouped together for statistical purposes. Three infants had late decelerations. This group was excluded from analysis because of the small sample involved.
Significant correlations were noted between the CPK values in the moder- ate-severe group compared with the groups with no decelerations and mild de- celerations as shown below:
. t
TJPE OF DECELERATION NONE MILD MOD-SEVERE P VALVE -- _._- CPK TOT. (mean) 528 540 1069 a.04 CPKl (mean) CPK2 (mean) %CPK3 (mean) CPK3 (mean)
7.4 7.6 17.5 4.02 23.0 29.5 101.5 <.02 94.7
?Z 90.7 c.02
498 951 ~055 (borderline significance)
No correlation (Spear-man) was found between CPK TOT., CPKI_3, or % CPKl-3, andpregnancyhistory, race,useofpitocin, use of anesthesia, tYPe of obstetrical care, and EKG abnormality. In addition, no correlation was found between total CPK, CPKi_3 or % CPKl_3 and five minute apgar, birth weight, mother's age, neonatal heart rate, or gestational age. Analysis of mode of delivery compared to all CPK valws revealed no significant difference.
CPK TOT correlated negatively with one minute apgar (p<.OO2) and CPKi correlated similarly (pC.007). Infants with delivery complications fre- quently associated with asphyxia (meconium staining, nuchal cord, cord pro- lapse) had significantly higher CPK's (total, CPK2, X CPK2, CPK3, % CPK3) than those infants without delivery complications.
Stepwise regression of analysis of variance revealed a significant con- tributionmto CPKl from decelerations (rs0.33, p(.O3) and head circumference (r10.48, ~‘~02). Decelerations (r=0.56, pCOO6) and OFC (r-0.42, p<.OO4) also contributed significantly to CPK2. Only 1 minute apgar (r=0.47, p(.OOl) and OFC (r-=0.58, pC.01) contributed to CPK3. The same two factors (r=O.46, p( .002 and r-50.58, p(.OO7. respectively) contributed to CPKTCT.
These data support the use of CPK and CPK isoenzymes as a measure of cel- lular damage in asphyxiated infants. Interestingly, infants with moderate- severe fetal heart rate decelerations had chemical evidence of mcrl’ ~~c~llu.lar damage to brain and heart than to muscle compared to inf:tntF r,fi tli ::i,r-mal FHll tracings or those with only mild variable decelerations. As ~fl~c~t~lc’rat iC,,7!5 wot-s~~~~~~d. ‘1. ?;I:! 11 l<'1‘ ,l('l-i'l.':,l :,,rti ‘l, I:;tal CPK arose from mu<:,-1 L' anl! tll:~:; more' From brain and Iwart. .Tht~ data tl~us add further support tn abnormal frrtal heart rate pnI_tcrns a:; an indicator of fetal asphyxia.
trtday, Apri-I 3 1:45 - ?:OO p.m.
INCIDENCE OF DOPPLE_R_DETECTED AIR EMBOLIZATION DURING EPIDURAL CATHETER INSERTION _--..--
John S. Naulty, M.D., ~- Gerard W. Ostheimer, M.D., Sanjay Datta, M.D:, Robert M. Knapp, M.D., Lee S. Perrin, M.D., Jess B. Weiss, M.D.
Air embolization has been reported during many surgical procedures, as a con- sequence of intravenous therapy and during diagnostic procedures. Air embol- ization can occur whenever the local venous pressure is lower than the pres- sure in the air source. These conditions may exist in patients during the insertion of epidural catheters. We therefore have assessed the incidence of detectable air embolus during epidural catheter insertion in pregnant females, using a widely employed, safe, non-invasive system of doppler detection of small quantities of air.
At present, 17 healthy parturients who were having epidural catheters for ob- stetric procedures, either labor and delivery or cesarean section have been studied. All had a precordial doppler (Brattle Instruments Co.) placed over the third to sixth intercostal space along the right sternal border. Five cc of saline was rapidly injected IV to confirm the placement of the doppler.
An epidural puncture was performed using our standard technique, a hanging- drop with a 17 ga Weiss needle, with confirmation with a loss-of-resistance test with air in the left lateral decubitus position. A 19 ga epidural cath- eter was then threaded caudad, and the catheter secured. After the catheter was secured, a second 5 cc IV saline dose was administered to reconfirm dop- pler placement. The incidence of doppler-detectable air embolization was re- corded.
To date (1-13-81) the following data have been recorded.
AIR DETECTED AIR NOT DETECTED ___ __-----
# PATIENTS I 8 9
NPO status(hrs) 12.5 2 3.5 6.2 + 92.6 PC.01
IV fluids (cc) 658 5 230 &&5 t 435 PC.02
Blood in needle lumen (X) 50 0 k.001
Our results show that transient air emboli may be detected during epidural ca- theter insertion. In our healthy parturients, this occurrence was without seri- ous sequelae. Predisposing factors may be previous hydration and perforation of blood vessels by the epidural needle.
36
Friday, April 3 2:DO - 2:lS p.m.
End Tidal CO7 Values Durin General Anesthesia for Cesarean Section. A.S. Wheeler, w, T.D. Bogard, FgM. James, III, D.M. Dewan. Bowman Gray School of Medi- c ne of Wake Forest University, Winston-Salem, North Carolina 27103.
Introduction. Controlled, maternal hyperventilation can produce decreased uter- ine blood flow and fetal oxygenation, especially when PaC02 values fall below 25 torr. Although excessive ventilation should be avoided during general anes- thesia for cesarean section/surgery in pregnancy, we are unaware of any reports in which continuous analyses of pCO2 values and ventilation are made. Several compact, reliable, and relatively inexpensive end-tidal CO2 monitors have re- cently become available, making continuous on-line assessment of maternal ven- tilation quite feasible. <...j. ^ I
Methods. Twenty normal, healthy term parturiehts scheduled for elective ce- sarean section (primary or repeat) received mylanta,'30 ml p.o., before trans- portation to the delivery suite (in lateral position). Following a 15O left lateral tilt, preoxygenation was accomplished for 10 min, with end-tidal CO2 values being continuously measured + from a'14 g angiocath placed through the side of a snugly placed anesthesia mask. Anesthetic induction entailed thio- pental, 3-4 mg/kg - maximum dose 300 mg. and succinylcholine, 120 mg intra- venously. Nitrous oxide, oxygen (412 L), and a succinylcholine infusion main- tained anesthesia until dellvery. End tidal CO2 values were measured contin- uously from the anesthesia Y piece and recorded immediately after intubation and every min thereafter. (The individuals providing controlled ventilation by hand were blinded to end-tidal CO2 levels.) To correlate end tidal and arterial CO2 values, arterial blood was obtained in 10 mothers at time of u- terine incision. Umbilical artery and vein cord gas values were determined in all 20 cases. FETCO, was converted to.PETC02:- PETC02 = (PB-PH20)x FETC02. L Results. Mean clinical parameters (A S.D.) for the 20 patients include: Age - 25 + 6 yr; weight - 75 2 13 kg; gestation - 39 + 1 wks; dnduction to de- livery ti.me - 7.2 & 2.8 min; and uterine incision to delivery time - 55 + 2g sets. The mean end tidal CO2 value before induction was 25 It 4 torr; the- average increase during laryngoscopy and intubation was 3 torr (Table 1). End tidal CO2 never exceeded 40 torr; in one patient, a progressive decrease to levels in the teens occurred and was associated with low umbilical venous and arterial PO2 levels. 'The correlation between end-tidal and maternal arterial PC02 levels was excellent, rL0.92, P<O.Ol. However, end-tidal values were al- ways lower than arterial, the mean difference being 6 + I torr. End-tidal values at delivery correlated less strongly (r=0.54) but signTficantlp (P<O.Ol) with umbilical venous PC02 values, mean difference = 14 t 3 torr. End tidal CO2 val.ues djd not correlate with umbilical vein p02 orpH values, which were nor- mal except in one patient.
summn. Continuous end-tidal CO2 monitoring ailows on-line assessment of de- gree of maternal ventilation. PaC02 is predicted by: FETC02 (700) + 6. We try to maintain an FETC02 of 0.035 to 0.042 during'general anesthesia, thus allowing an approximate PaC02 of 30-35 torr.
Table 1. Mean End-Tidal CO2 Values (+ SD) before induction (RI), immediately after intubatlon (PT) and every min thereafter. (* P < 05, values vs those be- fore induction).
BT PI 1." 2" 3" 4" 5" 6"
PrrC02 25 + 4 28 t 4* 29 -I- 3* 29 + 4* 29 4* 70 + 5* 31 4* 31 4* _. + .- + +
(torr) (n=20) (n=20) (n=20) (n=20) (n=lg) (n=16) (n=14) (n=12)
+ Datex CD101 CO2 Analyzer, Aimex, Co., Boston, Mass.
37
Friday, Ap;il 3 2:15 - 2:30 p.m.
Title: Effect Of*2Chloroprocaine Versus Bupivacaine On Uterine Contractions In Women During Labor Authors: Shaesta G. Humavun M.D., M. Rafique Chaudhry M.D., Abraham Lichtmacher M.D., M. Leon Tancer M.D., Adel R. Abadir MD Brookdale Hospital Medical Center, Bklyri., N.Y.
Uterine activity during lumbar epidural analgesia with Bup- ivacaine(1) and Lidocaine(2) were quantitated using Montevido Units. We applied the same units of measurement to evaluate the .effect of 1% and 2% ZChloroprocaine verus 0.25% and 0.5% Bupi- ’ vacaine on uterine activity during the first stage of labor. Twenty full term parturients in spontaneous labor were included.
Hethods and apparatus: An internal fetal electrode was used to monitor the fetal heart rhte.A transcervical intrauterine pre- ssure catheter was connected to a pressure transducer.Baseline uterine pressure, amplitude of contraction and frequency were continuously recorded. The index of uterine contractility (CI) was calculated by: CI= PxP in Montevido Units. P= Intensity of contraction measured by the increase in amndotic fluid pres- sure and F= number of contractions per minute. The efficacy of analgesia was quantited by each patient on a scale of l-4. Dermatomal spread, arterial blood pressure, fetal heart rate and variablity were monitored. A lumbar epidural catheter was inserted(cervix 4-6cm station -1 to 0) without test dose. Hypot- tension was avoided by administering lactated ringer's solution (500~~) and maintaining left uterine displacement. Patients were divided randomly into four groups. All medications were used without Epinephrine. Group l(l-5 Pts.) 0.5% Bupivacaine 5ml. Group 11(6-10 Pts,) 0.5% Bupivacaine 5ml. Group lll(ll-15 Pts.) 2% ZChloroprocaine 6ml. Group lV(16-20 Pts.) 1% ZChloroprocaine 6ml. All results are expressed as.the mean + S.E.M. ( Standard Error Mean). Statistical analysis was performed by the analysis of variance and paired t test. The null hypothesis was rejected .when a P value of less than 0.05 was obtained. Mean and Stand- ard Error Deviation was demonstrated for each 10 minute interval before and 10, 20 .and 30 minutes after the,administration of drug.
Result and Discussion: Changes in uterine contractility after the epidural were insignificant in Group 111 and IV. In Group 1 and 11, there was no drop in the activity during 10 and 20 interval following epidural although at 30 minutes interval there was a drop in CI but it was not significant. The data from our study indicated that none of the drugs used in the doses and concentrations mentioned above do interfere with uterine activity to a significant degree; moreover anaglesia was found to be adequatein most patients regardless of the concentrations used. Duration of analgesia as expected was less than one hour with ZChloroprocaine and was considerably longer with Bupivacaine, no attempt was made to quantitate the mean duration with that drug. It is worth mentioning that there was no difference in the qualitv of analgesia with lower concentration of the drugs used. We recommend the use of the lower concentration of Bupivacaine or ZChloroprocain 1. Schall=nhrg. J-c. *uterine Activity mrlng Lumbar
Ipldural ~nalgc~ia with Bu~i~~cIne 1. Vrdcka, A., Kretchman. El. I Lftect of Condition md inhrlrtlon Im.stha=la on Uterine Activity
38
Friday, April 3 2:30 - 2~45 p.m.
INF'LUEIICE OF EPIDURAL ANALGESIA FOR LABOR ON MATERNAL SELF-ESTIX.i AND PERCEPTION OF THENEWBORN
Hughes SC, M.D., Marut J, R.N., M.S.N., Slavazza K, R.N., Rohde JM, R-N., -M.D. , Shnider SM, M.D.
Departments of Anesthesia, Obstetrics, Gynecology and Reproductive Sciences, and the School of Nursing, University of California, San Francisco
The impact of obstetric analgesia on the maternal psychological experience of labor and her perception of the newborn, have been widely discussed in lay and medical literature. Some authors have suggested that epidural anesthesia, by blunting the sensation of uterine contractions and removing the pain of delivery, produces maternal deprivation and reduces maternal self-esteem, which in turn leads to general dissatisfaction with the birth experience. These authors also suggest that adverse effects on maternal-infant bonding occur. Using a variety of psychological tests, we at$qmpted to substantiate
Gte these suggestions. _ METHODS We studied 77 primagravidas selected atkndom who underwent uncomplicated
pregnancies and deliveries with varying anesthetic techniques. Three groups of women could be identified according to the intrapartum anesthetic they received: 1) local anesthetic without narcotic premeditation (n = 21), 2) local anesthetic with narcotic premeditation (n = 23), or 3) epidural anesthesia (n = 33).
Each group was further divided into those who had completed a Lamaze training course and those who had not. Three psychological tests were admin- istered 24-48 hours after delivery.
The first test used to determine maternal self-esteem was the Rosenberg Self-esteem Scale. Women rated ten statements that reflect self-acceptance and self-approval. The second test used was the Satisfaction Assessment of the Birth Experience Scale. In this teat, women rated 14 words or phrases that relate to their feelings about the childbirth experience. The final test was the Broussard Neonatal Perception Inventory, which evaluated the success of the mother-infant relationship by comparing, through questions, the mother's perception of the behavior of an average baby compared with her baby.
RESULTS Our results demonstrated no differences in the Rosenberg Self-esteem Scale
or the Broussard test between the three anesthetic groups. Furthermore, within each group, there were no differences between women who had received Lemaze training and those who had not. An equally large percentage of women in each group demonstrated high self-esteem and a positive maternal perception of her infant. Finally, the Satisfaction Assessment of the Birth Experience Scale showed no differences between the three anesthetic groups. However, patients with Lamaze training having epidural anesthesia had lower satisfaction scores than Lsmaze-trained women who had premeditation with local and/or narcotic analgesia. The patients without Lamaze training who received epidural anesthesia did not have lower satisfaction scores.
CONCLUSION We conclude that epidural anesthesia per se does not affect deve1opmer.t of
a normal maternal-infant relationship, maternal self-esteem, or self-satis- faction with the birth experience. We suggest that Imaze preparation should include a more realistic appraisal of the possibility of receiving anesthesia so that patients will not consider this aspect of the delivery a disappointment.
39
Friday, April 3 2:45 - 3:00 p.m.
IMPORTANCE OF PREANESTHETIC CONSULTATION PRIOR TO LABOR ON MATERNAL SATISFACTION WITH THE BIRTH EXPERIENCE
Barrier G, M.D., Garel &I, Jasson J, M.D., Legoff I., M.D.
Departement d'Anesth&ie-R&animation, HBpital Cochin Port-Royal, Paris, and I.N.S.E.R.M., Villejuif, France
To study maternal satisfaction with the birth experience when epidural analgesia had been given, we studied 163 healthy primaparous women who had uncomplicated pregnancies and vaginal deliveries.
METHOD All women attended Lamaze courses in preparation for child-
birth. If they planned to have an epidural anesthetic for labor to supplement their psychological preparation, they were offered an interview with an anesthesiologist_ Three groups of women could be identified. The first group consisted of 35 women who requested to meet with an obstetrical anesthesiologist for a preanesthetic consultation that included education about the techniques, benefits and risks of epidural analgesia. These wo- men planned to have, and indeed had, epidural analgesia during labor. The second group consisted of 73 parturients who decided only during labor to have epidural analgesia. The third group was composed of 55 parturients who underwent labor and delivery with the Lamaze technique alone. All 163 women underwent psych- ological assessment 24-48 hours after delivery. This assessment consisted of a self-administered questionnaire of 104 items and one or two interviews by a psychologist who was unaware if epidural analgesia had been used.
RESULTS The three groups were similar in their past medical and
antepartum obstetrical histories. The incidence of marriage, careers, and higher education was higher in Group 1. Women in this group were more satisfied with the birth experience than those in Group II or III: 25% of women in both Groups II and III were not satisfied with their experience, whereas only 5% of women in Group I were dissatisfied. Dissatisfaction in Group II was predominately due to fear, while Group III experienced more pain than they had expected.
CONCLUSIGN Although analgesia itself was equally effective in the
group receiving unplanned epidural blocks-compared with those who had planned epidural analgesia, antepartum preanesthetic consultation for analgesia and a more realistic recognition that anesthesia may be necessary, increased the likelihood of maternal satisfaction with the birth experience.
4n
Saturday, April 4 8:30 - 8:45 a.m.
GENERAL ANESTHESIA FOR CESAREAN SECTION: EFFECTS OF HALOTHANE ON MATERNAL AND FETAL ACID-BASE AND LACTIC ACID CONCENTRATION
S. Datta, M.D., G.W. Ostheimer, M.D., J.S. Naulty, MD., J-6. Weiss, M.D., L.S. Perrin, M.D., R.M. Knapp, M.D.
Nitrous oxide and oxygen with or without halothane supplementation before delivery is frequently used during general anesthesia for cesarean section. One of the beneficial effects of halothane is an increase in uterine blood flow. The present study was designed to assess the effectiveness of 0.5% Halothane in improving acid-base values of mothers and fetuses as well as decreasing the lactic acid concentration during its brief usage during elective or emergency cesarean section before delivery of the baby.
Twenty-eight parturients undergoing cesarean delivery under general anesthesia were selected at random. Twenty-four of the parturients were scheduled for elective section at term whereas four under went abdominal delivery for fetal distress (scalp pH 7.20 or below). The cases were divided into two groups depending whether they received halothane or not. Maternal blood samples were drawn prior to induction for estimation of pH and lactic acid. Maternal and neonatal acid-base values and lactic acid concentrations were determined also at delivery.
I-D interval (min) U-D interval (set) Apgar ~7
1 min 5 min
MA PH UV pH UA pH Lactate (pM/LL MA Preinduction At delivery UA *p-z.05
ELECTIVE CASES EMERGENCY CASES
Non-halothane n = 12
:;0
0 I
0
7.42 7.43 7.33 7.37 7.30 7.32*
1061 1150 2536 2600 1306 1259 2700 2650 1600 1474 4736 4960
Halothane n = 12
:;0
0 0
Non-halothane Halothane n=2 n=2
6 6 95 100
2 2 2 1
7.30 7.38 7.26 7.27 7.22 7.21
Significantly lower induction-delivery interval was found in case of emergency sections for fetal distress when compared to elective cases. In elective cases umbilical vein pH was higher in the group where mothers received halothane. There were significantly higher maternal and fetal lactate values in the fetal distress group.
Our results show during elective cesarean sections better neonatal acid-base values were.associated with the use of halothane. Fetal distress cases were associated with high maternal and fetal lactic acid values. 1 and 5 minutes Apgar scores were also lower in these cases.
43
Saturday. April 4 8:45 - SIOO. a.m.
DEXTROSE HYDRATION IN CESARBAN SECTION PATIENTS
N. Kenepp, S. Kumar,T.Valencia, B. Gutsche, S. Gabbe, M. Delivoria Papadopoulos
Temple University Hospital and the Hospital of the University of Pennsylvania
In patients undergoing cesarean section with regional anesthesia, prehydration with intravenous fluids has been recommended for prevention of hypotension. Use of solutions containing 5% dextrose may cause acute maternal hyperglycemia and subsequent neonatal hypoglycemia. This pro- spective study determines the effect of administration of various amounts of dextrose on neonatal glucose metabolism.
Informed consent was obtained from otherwise normal fasted term par- turients, not in labor, who were to undergo elective cesarean section. Subjects received 150 cc of 5% dextrose (D5W) plus either normal saline (NS) 1000 cc (Group A), 5% dextrose in normal saline (D5NS) 1000 cc (Group B), or D5NS 350 cc and NS 650 cc (Group C) prior to epidural admin- istration of 18-22 cc of 0.5% bupivicaine. NS (Groups A and C) or D5NS (Group B) was then infused until delivery of the fetus. Laboratory measurements included maternal serum control glucose, delivery glucose and pH; umbilical arterial and venous pH, pCO2, ~02, lactate and glucose; and neonatal capillary 1 and 2 hour glucose. Umbilical venous and neo- natal capillary 2 hour insulin, lactate, B-hydroxybutyrate, pyruvate, free fatty acids and glucagonwereobtained in 17 patients.
Statistical analysis was carried out by an unpaired two-tailed t-test or a chi-square test. The patients had similar ages, heights, weights,
parity, anesthetic doses and infusion to delivery intervals. The mean fluid received at the time of delivery in Group A was 1839 cc, in Group B 1867 cc and in Group C 1875 cc. Hypotension occurred in 42% of Group A patients and 71% of Group B patients. Urine output for 15 minutes was 11 cc in Group A and 53 in Group B. Fasting maternal glucose levels, 75 + 3 in both A and B and 71 in Group C, ranged from 51 to 94 mg percent. As we reported at the 1980 SOAP meeting, at delivery maternal glucose was significantly higher in Group B, as were umbilical cord glucose levels. Group B babies were acidotic with umbilical arterial pH 7.19 + .016 (Group A 7.25 + .012), and umbilical arterial lactate 2.5 + .23 (Group A 1.7 + .21). To date the umbilical venous and neonatal capillary pyruvate, B-hydroxy- butyrate and free fatty acid levels do not differ significantly. At 2 hours Group B babies were significantly hypoglycemic, mean 30 +_ 4.2, with a range from 5 to 55 mg percent (011 appeared clinically normal); Group A and C means were 63 and 44 respectively. Physiologic jaundice was sig- nificantly more severe in Group B infants. Insulin and glucagon results will be available at the time of presentation.
The addition of dextrose to crystalloid fluids presents no advantage for preventing hypotension. and may decrease volume expansion through osmotic diuresis. 150 cc of Dc,!J provided a normal glucose in all Group A patients; whereas 5UO cc of 5% dextrose decreased the glucose level in one patient. Increased gl.~~cose metabolism in a normally oxvgen poor environ- ment might cause the fetal acidosis demonstrated. Elevated heme oxygennse icvels induced durin,: the period of hypoglycemia after birth probably callsed the hyperhilirubenemia in Croup B infants. Thus rapid administra- tion of dextrose, elevating maternal blood sugar above normal, is drtri- mental to the fetus and has no therapeutic value for the mother. Pat ients undergoung cesarean section should rec.eive no more than 5 grams per hour prior to delivt~rv.
Saturday, April 4 g:OO - 9:15 a.m.
THE INTERACTION RETlJEEN RUPIVACAINE AND Z-Ctll.OROPROCAINE
Corke, B. C., M.D., Dettbarn, W-D., M.D., Carlson, C. G., Ph. D., The Department of Anesthesiology and The Jerry Lewis Muscular Dystrophy Center, Vanderbilt University School of Medicine, Nashville, Tennessee
The first dose of an epidural aneshtetic given during labor should be a rapidly acting and rapidly metabolized drug such as Z- chloroprocaine, since this will:
a) provide fast relief of pain
b) have limited toxic effects should the drug be accidentally injected intravenously
A longer acting drug such as bupivacaine may then be used for subsequent dosage. Chloroprocaine, used clinically, however, attenuated the analgesic effect of a subsequent administration of bupivacaine and shortened the time course of bupivacaine action from 2 hours to 40 minutes. If, however, chloroprocaine was given repeatedly, each injection produced adequate analgesia for the expected 35-45 minute period.
To examine the mechanisms by which chloroprocaine attenuates the action of bupivacaine, studies were commenced using animal models. The sciatic nerves of rats anesthetized with ketamine were stimulated and the threshold voltage required for a leg twitch was measured. Following recovery from exposure to chloroprocaine the length of action of bupivacaine was considerably reduced compared to rats treated only with bupivacaine. A similar result was seen when unanesthetized rats were given tail blocks with these local anesthetics. When isolated sciatic nerve preparations were subjected to local anesthetics in a conduction chamber; a similar attenutation of the action of bupivacaine was seen when the nerves were pretreated with 2-chloroprocaine.
This effect does not seem to be related to the acidity of the chloroprocaine solution (pH 3.1) since:
a) in intact rats prior treatment with a solution buffered to pH 3.1 failed to alter the action of bupivacaine
b) in the isolated nerve preparations b,>th local anesthetics wsre used in Ringer’s lactate buffer at a pH of 7.2
Another possible reason for this phenomenon is th.lt a metabolile of 2-chloroproc:;ine, which by itself does not produce a block in conduction, interferes in some way with the action of bupivacaine. Procaine amide, which is not hydrolyzed by chloinesterase, when
administered before bupivacaine, did not interfere with the action of hupivncaine . . Further studies are in progress in an attempt to elucidate the nature of the 2-chloroprocaine blocking effect upon the subsequent action of bupivacaine.
Saturday, April 4 9:15 - 9:30 a.m.
THE EFFECT ON THE VISUAL PREFERENCES OF NEWBORNS FROM EXPOSURE
Tb ANESTHETIC AGENTS EARLY IN PREGNANCY
Virginia W. Blair, A.L. Hollenbeck, Robert F. Smith of George Mason University, Fairfax, Virginia and John W. Scanlon, of Columbia Hospital for Women and Georgetown University, Washington, D.C.
No valid data exist about human behavioral effects subsequent to anesthesia exposure early in gestation. However, such effects have been found in animals. Data do exist which suggest obstetrical anesthesia may have an effect on newborn behavior, particularly early neonatal cognitive and social behavior. While such effects in the human do not appear to be permanent, animal studies have shown that anesthetic exposure very early in gestation may have behavioral conse- quences which may persist into adulthood. Thus to define potential consequences from prenatal exposure to anesthetics on subsequent behavioral development becomes a compelling issue for study. This paper presents preliminary.observations which are part of a larger project to investigate the effects of early gestational anesthetic exposure on neonatal visual preferences.
A random sample of 39 infants had visual pattern preference testing based on the work of Miranda and Fantz. Following test- ing, a careful perinatal history was obtained which included information about exposure to exogenous substances during pregnancy. Such history of early gestational exposure were checked by direct contact with the responsible physician or dentist.
Twenty three percent of patients had a history of early trimester drug exposure. Two of these infants were exposed twice during gestation. This is double the reported rate of early trimester drug exposure from previous large perinatal studies.
On the visual test, the exposed infants had significantly longer ( p<.OOOl) looking times than did unexposed infants. Furthermore, drug exposed neonates had longer looking times for less complex pattern than did non-drug exposed babies. This suggests an effect on visual discrimination as well. These preliminary results suggest that anesthetic exposed fetuses may have developmental delay of visual attention and dis- crimination. The results will be discussed in terms of utility of visual preference testing for detecting subtle prenatal drug effects as well as the obvious implications of these preliminary results.in the context of current medical and dental practices on preqnant women.
46
Saturday, April 4 9:30 - 9145.a.m.
NEONATAL BLOOD LEVELS AND NEUROBEHAVIORAL RESPONSES AFTER EPIDURAL ANESTHESIA WITH CHLOROPRCCAINE, L
Thet-ese Abboud MD, V. Williams MD, F. Mil J .P. Van Dorsen MD and
DOCAINE AND BUPIVACAINE ,I
I et- MD, E. Henriksen MD, T. Coan MD, S. Earl, CRNA
Department of Anesthesiology, Obstetrics a n d Gynecology, LAC-USC Medical Center
Epidural anesthesia is frequently used for pain relief in the parturient. The present study was undertaken to measure the placental transfer of three commonly cased local anesthetlc agents, and to evaluate their effects on the mother, the fetus and the neonate. Method : Eighty-seven healthy parturients electing to have epldural anesthesla for laborand dellvery were studied. The study was approved by the Human Research Com- mlttee and informed consents were obtalned. All patients had direct fetal heart rate monitoring and uterine pressure was measured by an intrauterine catheter. Epldural catheters were placed in the usual manner and a 30 minute observation was made of the following parameters: fetal heart rate (FHR), fetal heart rate variabllity (FHRV), uterine actlvlty (UA), maternal blood pressure and heart rate. Patients were then given I of 3 local anesthetics in a randomlzed manner. (1) Group I (n=28) bupiva- Caine 0.5% (2) Group II (n=B) 2-chloroprocaine 2% (3) Group III (n=3l) Lldocaine 1.5%. Epldurals were reactivated as clinically Indicated and observations continued till delivery. At time of delivery maternal venous and cord blood samples were ob- tained for measurement of local anesthetic levels and determination of the acid base status of the neonate. Apgar scores were noted and early neonatal neurobehavioral examination (ENNS) was performed at 2 and 24 hours of age. The data were evaluated for significance by analyses of variance, Student’s t-test and chi-square. Results
are summarized in the table: -. _ -1
-__
31
2
4
N=
Materna I hypotens ion (n= 1
Significant periodic (n=) FHR Patterns
FHRV
Uterine activity
ENNS
UA-pH
UA-BD (Meq/L)
Acidemia” (n=)
Apgar Scores<7 at l/5 min.
Mean Loca I Anesthet its Leve 1: (uq/ml) at time of delivery:
MV
UV
UA
UV/MV .-__ ._- __
BUPIVACAINE
28
3
--
9
NS
NS
NS
7.28
7 3
S/O
‘3.86
0.14
J. I3
ti. I6 - --~
-l- _.
CHLOROPROCAINE
20
6
I
NS NS
NS NS
NS 14s
7.24 7. %h
7 !
3 5
6/O 3/O
I.16 l-J.{:1
O.nB
O.69
P _-
NS
< 0.0:
NS IJS
NS
* Umbilical venous pH<7.25 or umbilical arterial pH(7.20
Saturday, Apri I 4 11:oo - 11:15 a.m.
THE EFFECT OF LOCAL ANESTHETIC AGENTS ON THE pH of EPIDURAL FLUID
Robert H. Hall, M.D., LDS Hospital, Salt Lake Ci ty, Utah 84143
During the past seven years 2-chloroprocaine (2cp) has been used exten-
sively for epidural anesthesia at LDS Hospital without a single known incident
of prolonged neural blockade with nerve deficit. In attempting to account
for the absence of this complication in over 30,000 epidural blocks given
during this time period, consideration was given for the fact that most blocks
were initiated with bupivacaine, possessing a higher pH, and were terminated
with 2cp to create prompt, complete perineal anesthesia, and to permit rapid
disappearance of the block postpartum. It is postulated that bupivacaine
might mitigate against the low pH effect resulting from the subsequent in-
jection of 2cp, thereby protecting the patient from prolonged neural blockade.
To evaluate this phenomenon, specimens of epidural fluid were obtained
from 50 obstetric patients by catheter aspiration at the conclusion of de-
livery to study ptl of the fluid of patients receiving (1) bupivacaine alone,
(2) bupivacaine followed by terminal injection of 2cp, and (3) patients re-
ceiving 2cp alone. pH detetminations were made by glass electrode technique,
and all specimens were compared with direct pH determinations of .25, .5,
and .75% buplvacaine and 2 and 3% 2cp. The results of the studies demonstrate
the following:
LOCAL ANESTHETICS USED FOR EPIDURAL ANESTHESIA AVERAGE pH OF EPIDURAL FLUID
Bupivacaine alone 6.33
Bupivacaine followed by 2cp 5.30
2cp ala In
In conclus i
tion of epidura I
e 3
on, epidural injection of bupivacaine early i
anesthesia with subsequent injection of 2cp
2
n the administra-
results in a high-
er pH of epidural fluid obtained at the conclusion of obstetric delivery than
when 2cp is administered as the sole anesthetic agent.
49
Saturday, April 4 11:15 - 11:30 a.m.
EVALUATION OF LOCAL ANESTHETICS FOR NEUROTOXICITY FOLLOWING SUBAP.ACHNOID INJECTION
Rosen MA, M.D., Norton M, M.D., Curtis JD, M.D., Hughes SC, M.D., Collins WM, M.D., Davis RL, M.D., Levinson G, M.D., Shnider SM, M.D.
Departments of Anesthesia, Pathology, Obstetrics, Gynecology and Reproductive Sciences, University of California, San Francisco
Recently several case reports have described prolonged sensory and motor deficits following inadvertent spinal anesthesia with large volumes of chloroprocaine. Although it is well established that small doses of local anesthetics injected into the subarachnoid space do not produce neurotoxicity, the effects of large doses and volumes have not been examined carefully. The purpose of this study was to evaluate the possible neurologic sequellae from subarachnoid injections of large volumes of local anesthetics in sheep.
METHOD wers were placed in the internal carotid artery and jugular vein of
adult sheep anesthetized with halothane in oxygen via an endotracheal tube. A lumbar puncture was performed with a 22-gauge needle. Samples of cerebro- spinal fluid were collected for chemical analysis (pH, protein, glucose, CPK, LDH, lactic acid) and cell count (RBC, WBC with differential count), The animals then received 10 ml of one of the following solutions via the spinal need1 e : 1) 3% chloroprocaine, 2) 2% lidocaine, 3) 0.75% bupivacaine, 4) the carrier agent of 3% chloroprocaine (pH 2.32 to 3.3). or 5) Elliot’s B solution (mock CSF). Another group received no anesthetic or solution after undergoing lumbar puncture and collection of CSF. Each animal receiving a local anesthetic rapidly achieved high spinal anesthesia and arterial hypo- tension. Hypotension was corrected with intravenous administration of ephedrine and infusion of a balanced salt solution. Arterial blood gases were measured at frequent intervals and ventilation was controlled, when necessary, to maintain normal PaC02. Once the animal was awake and able to sustain normal spontaneous ventilation and blood pressure, the trachea was extubated and the animal returned to a holding pen. Each animal was observed daily for signs of neurologic deficit. On day 7, each animal was tested for motor and sensory function. Lumbar puncture was then performed and cerebrospinal fluid collected for repeat analysis. The animal was then sacrificed and an autopsy performed for gross and microscopic examination of the lumbar and lower thoracic spinal cord, meninges and brain.
RESULTS No animal had abnormal results from tests of sensory or motor function. No
local anesthetic produced consistant abnormalities in biochemical analysis of cerebrospinal fluid. Histologic examination revealed local trauma at the site of needle insertion, but no evidence of menigitis, arnchnoiditis or myelitis.
CONCLUSIOY Large subarachnoid doses of 2% lidocaine, 0.75% bupivacaine, 3% chloropro-
cnine, or the carrier agent of 3% chloroprocaine are not neurotoxic in sheep.
50
Saturday, April 4 11:30 - 11:45
Title : Neurological effects of subarachnoid injection of large volume of 2 chloroprocaine CE and bupivacaine in dogs
Authors : R. S. Ravinciran M.D., M. Turner M.D., J. Muller M.D.
Affiliation - : Department8 of Anesthesia, Heuroeurgery, Neuropathology, Indiana University School of Medicine, Indianapolie, Indiana 46202
Introduction. Ravlndran et al (1) and Raiener et al (2) reported that two of their patients who had received continuous epidural anesthesia and two patients who had received inadvertent subarachnoid injection with 2-chloroprocaine-CE developed significant neurological complications. In their editorial comments Marx, Cavino and Finster stated that neurological complication5 were more.likely to follow inadvertent subarachnoid injection of a large volume of 2-chloroprocaine-CE (3). We undertook this prospective animal study to determine the reproductibility and incidence of neurological dysfunction following subarachnoid inJection of 2-chloro- procaine-CE in dogs. Bupivacaine was also evaluated in the same animal model.
Methoda. Thirty-five mongrel dog5 (8 Kg to 18 Kg) were studied. The dogs were eedated with intravenous ketamine. A percutaneous spinal tap was accomplished in the lumbar area with 20-gauge spinal needle in lee8 than 3 attempts. Clear spinal fluid was withdrawn prior to injection of the drugs in all dogs. Six to 8 ml of 33 P-chloroprocaine-CE (pH 3.3) or 0.75% bupivacaine (pH 5.4) based on the length of the dogs were administered. Twenty dogs received 2-chloroprocaine-CE (Croup 1) and 15 dogs bupivacaine (Croup 2). Following intrathecal injection of local anesthetics, the tracheas of the dogs were intubated and ventilated with 100% oxygen. Intra- arterial blood pressure was monitored and maintained within normal limits. Follow- ing resumption of adequate and spontaneous ventilation the endotracheal tubes were removed and the dog8 were observed in the chronic care facility for any evidence of neurological dysfunction. Croup 1 dogs were sacrificed on the 15th day. Croup 2 dogs that did not show any evidence of neurological dysfunction were sacrificed on the 7th day. The spinal cords were removed, and sections were taken from different levels of the spinal cord for microscopic examination.
Results. All dogs rapidly became apneic following intrathecal inJection of the local anesthetics. With regression of anesthesia all the dogs in Croup 2 walked spontaneously within 12 hours. T‘nirteen of the dogs in Croup i walked spontaneous- ly uithin 12 hours. The remaining seven dogs in Croup 1 developed paralysis of their hind limbs and all remained paraplegic till they were sacrificed (5) or died (2). Slides showing histopathological changes will be presented.
Conclusions. Intrathecal injection of large volume of 3% 2-chloroprocaine-CE in dogs caused paraplegia in 15': of the animals. InJection of 0.75% bupivacaine di$. not cause any detectable neurolopical dysfunction. I I
Reference. Anesthesia and Analgesia. 59: 1(447-1451), 2(452-454), ?(39?-400)”
51
Saturday, April 4 11:45 - 12:oo
NOON
The Toxicity of 2-Chloroprocaine and Lidocaine on Peripheral Nerves of Rabbits
S.J. Riggi, S. Harding, n. Hashim and 0. Hinsvark
Pennwalt Pharmaceutical Division Rochester, New York 14623
In view of a preliminary report (Barsa et al., Anesthesia and Analgesia, 59:1980) suggestive of unique neurotoxicity of 2-chloroprocaine (2-CP) on the rabbit vagus, and the possible adverse effects of solutions ‘of low pH on neural tissue suggested by others, studies were undertaken to more thoroughly evaluate the toxicity of 2-CP and acidic solutions, as compared to lidocaine on peripheral nerves of rabbits. Rabbit vagi were exposed, according to Barsa’s procedure, In an open wound for one hour with 7 ml of 3% 2-CP, 2% lidocaine or the vehicle for 2-CP (pH-3). all with l/200,000 epinephrine (epi), for one hour, the wound closed and the animals killed 11 days later. In agreement with Barsa, marked adhesions around the vagus were observed in 2-CP treated animals. However, in marked contrast to his report, the effect was also observed in the lidocalne treated group. Animals treated with vehicle (pH-3) were normal. Since this model includes exposure of drug solutions to the atmosphere in an open wound for one hour, possible resultant changes in 2-CP solutions were evaluated as contributory to the adverse effects. Rabbits treated with a slurry of 2-CP dithionate crystals (a possible product of oxidation in 2-CP solutions when exposed to air for protracted periods of time) either with the wound immediately closed or after exposure of the wound with saline for 1 hour followed by addition of crystals, were found normal. In addition, solutions of 3% 2-CP with epi, which were allowed to stand open to air in beakers for 1 hour and injected (7 ml) next to the vagus through surgically implanted catheters, did not produce toxic effects. Indeed, when fresh so,lutions of 3% 2-CP or vehicle (pH-3) with epi were similarly injected (7 ml) through a catheter, no toxicity was found 11 days later.
The toxicity of 2-CP and lidocaine on rabbit brachial plexus was also in- vestigated. Animals were injected in the left axilla daily for 8 days with local anesthetic solutions, or their respective vehicles, in volumes equal to 2-6 times the acute dose used in man. The right axilla was injected with an equivalent volume of saline. Gross and histopathology did not reveal drug related toxicity in any group.
These data indicate that 2-CP, lidocaine or solutions of low pH are not
overtly toxic to peripheral nerves of rabbits, when administered in massive doses, relative to doses lrsrd in man, when injected into intact tissues In a manner comparable to that rlsed clinically. The effects described by Rnrsa et al. have been confirmed in Z-CP and lidocaine treated anfm;lls, b;lt rl:mnin unexplained. The possible role of cllange in 2-CP solutions with expu.su~-c to the nfmosphere was investigated and not found contributory. Sirlce tlte cffec.t described by R,irsa et al. is limitk~d to a highly specific and ~lrlptlysiolc~gical model, the mcadingflll extrapolation of these limited findings to potential clinic,al toxicity is equivocal.
52
Saturday, April 4 12:00 - 12:15 p.m.
A& of InvestiBatio_n_: Recently, there have been scvcral cases and re- ports of adverse neurological reactions following the use of 2-ChIoroprocaine. These complications have occurred in epidural, fnterscalene, and snpra- clavicular brachial plexus blocks. The present studv is a comnarison of the relative local histotoxicity of cquinotent masses, volumes. and concentrations of lidocaine, bapivacaine, and cl~loronrocaine in an experimental, in viva animal model.
?Iethods : A trough was made around the cervical oortion of the rahbit vagus nerve and f ts surrounding tissue. The vagus nerves were cxnosed to various masses of lidocaine 12, 2::. bupivacaine (Yarcaf.ne@) 0.57, 0.75X, al with epinephrfne l:ZlO,fir)O, and 2-chloroprocaine (Nescaine CE @) 77, with and without epinephrine. A proup of vagus nerves was exposed to a pll neutralized solution of 2-chloroprocaine (CE). Control nerves were exposed to saline, sodium bisulfite, with and without epinephrine. Ten to twelve days later, the nerves and the surrounding tissues were examined for gross morphology, conduction, and microscopic appearance.
1
Results : -- The nerves exposed to lidocaine and bupivacaine with epineohrine (n=12) appeared for the most part normal on cross and micro- scopic examination and in conduction studies, as did the control nerves (1~22). including the nerves exposed to sodium bisulfite. ‘[any of the nerves exposed to Fchloroprocainc 37 (n-14), including those exposed to the pH neutralized solution, exhihited adhesions and encapsulations on Rross examination, loss of conduction, extraneural tissue reaction, perineural fibrosis, and axonal degeneration. The histotoxicitv and loss of cnnduction were more severe when epineph,rtne was added to the ?-chloronrocatne solution.
Conclusions: 2-cliloroprocn~ne, I.n an equipotent mass and concentration to that of lidocaine and bunivacaine with eninephrine, produced far more extraneural and neural tissue abnormalities than the other local anesthetics in this experlnental animal modsl.. The adtlitfon nf epinep?irine to ?-chloroprocaine 3: mar!:er!lv i.ncreased the local hfstotoxicitv.
53
ABSTRACTS SUBMITTED BUT NOT PRESENTED
Exploration of mental health preventive intervention in the neonatal intensive care unit and the home: a family care program. P. Allison, J.W. Scanlon, K. Scanlon. National Institute of Mental Health, Adelphi,
Maryland; Department of Pediatrics, Georgetown University School of Medicine, Washington, D.C.
The clinical experience with the bleeding time as a measure of platelet
function in patients with severe preeclampsia. T.J. Benedetti, J.C. Hargrove,
Z.A. Brown. Departments of Obstetrics and Anesthesiology, University of
Washington.
The maternal and fetal cardiovascular effects of eoidura) morohine. J.B. Craft,
J. Bolan, L.A. Coaldrake, P. Hazel, R.M. Gllman, L’.K. Shokes,‘W.A. Woo 1
Departments of Anesthesiology, Obstetrics and Gynecology, and Pharmaco 11
f.
ogy * George Washington University Medical Center, Washington, D.C.
A comparison of epidural meperidine and bupivacaine for the rel
pain. S. Bra~ell, W. Hammonds, C.C. Hug, Z. Najak. Departmen
Anesthesiology and Pediatrics, Emory University School of Medic
Georgia.
ief of 1 abor
ts of
ine, Atlanta,
Follow-up of hyperventilated neonates. C. Brett, M. Dekle. C.H. Leonard,
C. Clark, 5. Sniderman, R. Roth, R. Ballard, I?. I. Clyman. Department of
Pediatrics, Mt. Zion Medical Center, San Francisco, California.
Oxyhemoglobin affinity t buffering capacity in infants of diabetic mothers.
R.G. Brouillard, J.L. Kitzmiller, S. Datta. Brigham and Women’s Hospital,
Boston, Massachusetts.
Neonatal heart rate following maternal epidural anesthesia. W.U. Brown,
G.C. Bell, 0. Datta. Department of Anesthesiology, Vanderbilt University
School of Medicine, Nashville, Tennessee; Department of Anesthesia, Harvard
Medica 1 School , Brigham and Women’s Hospital, Boston, Massachusetts.
Chloroprocaine followed by bupivaca ine for maternal epidural anesthesia.
W.U. Brown, I_. Chen, M. Watkins, A, Edgar. Department of Anesthesiology,
Vanderbilt University School of Medicine, Nashville, Tennessee.
In vitro evaluation of antacids. H.T. Chung, L.F. Redick. Department of
Anesthesiology, Duke University Medical Center, Durham, North Carolina.
Cardiovascular effects and blood levels of intravenous fcntanyl i- the
chronic maternal-fetal sheep model. J.B. Craft, L.A. Coaldrake, J. Bolan.
P. Mazel, R.M. Gilman, L.K. Shokes, W.A. Woolf. Departments of Anesthesiology,
Obstetrics and Gynecology, and Pharmacology, George Washinqton University
Medical Center, Washinqton, D.C.
Fetal and maternal effects of sodium nitroprusside used to treat artificially
induced hypertension in gravid ewes. S.C. Ellis, A.S. Wheeler, F.M. James, Ill,
J.C. Rose, P.J. Meis, F.C. Greiss, Jr., 2. Shihabi. Departments of Anesthesia,
Obstetrics and Gynecology, Physiology and Pathology, Eoman Gray School of
Medicine of Wake Forest University, Winston-Salem, North Carolina.
Serial changes in glycohemoglobin (HbA,) in normal and diabetic pregnancies.
H.E. Fadel, T.A. Huff. Maternal-Fetal Medicine Sectlon, Department of
Obstetrics and Gynecology; Metabolic and Endocrine Section, Department of
Medicine, Medical College of Georgia, Augusta, Georgia.
Prevention of hypotension with hydration. C.P. Ci bbs, L. Spohr, 0. Paulus,
R. Schul tetus. Department of Anesthesiology, University of Florida,
Gai
Act 8.J
Hea I
esvi Ile. Florida.
on of local anesthetics on non-gravid uterine arteries. J. Gintautas,
Kraynack. Anesthesiology Research Laboratories, Texas Tech llniversity
th Sciences Center, Lubbock, Texas.
Cimetidine for prophylaxis of aspiration pneumonitis. R. Glassenberg,
A.J. Bart. Department of Anesthesia, Northwestern University Medical
School, Chicaqo, Illinois.
Brainstem evoked response in neonates. P. J. Goldstein, A. Krumholz, J. Felix,
0. Shannon, K. Harris. Departments of Obstetrics, Pediatrics, Neurology,
Rehabilitative Medicine, Sinai Hospital of Baltimore, Baltimore, Maryland.
Comparison of the effect of 4 hypotensive agents in the pregnant ewe. R. Hodqkinson. University of Texas Health Science Center at San Antonio.
Mendelson’s syndrome? R. Hodgkinson. University of Texas Health Science
Center at San Antonio.
Continuous infusion for Icmbar epidural analgesia durino labor. J. D Jones I I , A. Iwane, R. Hellman. Department of Anesthesiology, Washington University
School of Medicine, St. Louis, Missouri.
Neurological loss associated with vaginal delivery: report of twenty-eight
cases. T.H. Joyce, III University of Cincinnat i
U.T. Pai, D.M. Diaz. Department of Anesthesia,
Medical Center, Cincinnati, Ohio.
Cinscore - an obstetrical recovery room evaluation tool.
Department of Anesthesia, University of Cincinnati Medica Ohio.
T.H. Joyce, III.
1 Center, Cincinnat i ,
Eisenmenger’s syndrome in pregnancy: continuous epidural
elective cesarean section. B.J. Kraynack, J.A. Spinnato,
anesthesia for
M. W. Cooper.
Departments of Anesthesiology, Obstetrics, and Internal Medicine, Texas
Tech University Health Sciences Center, Lubbock, Texas.
Potentiation of magnesium induced neuromuscular blockade by gentamicin.
C.S. L’Hommedieu, D.A. Nicholas, W.P. Jones, T.E. Nelson, P.M. Huber.
Departments of Anesthesiology and Pediatrics, University of Texas
Medical Branch, Galveston, Texas; University of Texas Medical School,
Houston, Texas.
Sodium bicarbonate as an oral antacid. H.S. Lim, P.L. Tan. Department of
Anesthesiology, University of Chicago, School of Medicine, Chicago, I1 linois.
The effect of maternal glucose infusion on breathing movements in human
fetuses with intrauterine growth retardation. F.R. I.uther, K. Scott,
A. Allen, 0. Stinson, J.H. Gray. Division of Perinatal Research, Depart-
ment of Obstetrics and Gynaecplogy, Dalhousie University, Halifax, Nova
Scotia.
lsoflurane anesthesia for combined caesarean section and excision of
pheochromocytoma. G.D. Lyon, P.F. Norman, R.D. Wilson. Department of
Anesthesiology, University of Mississippi Medical Center, Jackson.
Mississippi.
Antiemetic effectiveness of intramuscular vistaril compared with intra-
muscular droperidol in patients undergoing therapeutic abortions. R. McKenzie, R. K. Wadhwa. Department of Anesthesiology, Hagee- Wornens Hospital, University
of Pittsburgh, Pittsburgh, Pennsylvania.
Vascular and extravascu
(hCg), follicle stimula ar concentr-ations of human chorionic gonadotropin
t ing hormone (FSH), and prolactin (PRL) in normal term pregnant women. G R. Meeks, N. Whitworth, J. Unger, J. Morrison, S. Marynick, P. Norman. Depar-tment of Obstetrics and Gynecology, University of Mississippi Medical Center, Jackson, Mississippi.
1 c
J
J
1
I I
I
1
J
1 I
‘1 s
L
1 I
‘1
The effects of maternal diabetes control on fetal lung maturity assessment. J.C. Morrison, P.M. Farrell, M.J. Engle, D.M. Menzel, S.G. Douvas, N.S. Whitworth, P.G. Blake. Department of Obstetrics and Gynecology, University of Mississippi Medical Center, Jackson, Mississippi; Department of Pediatrics, University of Wisconsin, Madison, Wisconsin.
Effect of intravenous fluids containing varlous concentration of glucose on maternal and fetal blood glucose levels. A.T.C. Peng, H.H. Shamsi, C.S. Elancato, F.A. Chervenak, J. Castro. Departments of Anesthesioloqy and Obstetrics and Gynecology. St. Luke’s - Roosevelt Hospital Center, New York, New York.
Screening term LGA neonates for hypoglycemia. H. Satish, G. Katzman, J. Williams, .I. Urrutia, P.L.S. Amma, I. Weinfeld, S. Kripke, V. Krishnan. Department of Pediatrics, The Toledo Hospital, Medical College of Ohio, Toledo, Ohio.
Gentamicin kinetics in very low birth weight neonates. M. Satish, T. Thompson, V. Krishnan, G. Katzman, J. Urrutia, 1. Weinfeld, S. Kripke, P.L.S. Amma. Department of Pediatrics, The Toledo Hospital, Medical College of Ohio, Toledo, Ohio.
The measurement and magnitude of lumbar epidural pressure. Y.-K. Tien, G. Edelstein. Department of Anesthesiology, University of Oregon Health Sciences Center, Portland, Oregon.
Suxamethon i urn apnoea : management implications. S. Varqhese. Johns Hopkins
Hospital, Baltimore, Maryland.
Relationship of fibrinogen levels to prolonged rupture of membranes and sepsis. D.-J. R. Walker, P.F. Twist. Nassau Hospital, Mineola, New York.
Three percent 2-chloroprocaine for cesarean section. Appraisal of a standardised
dose t.echn ique. W.D.R. Writer, D.M. Dewan, F.M. James, III. The Department of Anesthesia, Bowman Gray School of Medicine, Winston-Salem, North Carolina.
Effects of spinal anesthesia on maternal endogenous catecholamines and neonatal outcome. T. Abboud, R. Artal, E. Henriksen, S. Earl. Departments
of Anesthesiology, Obstetrics and Gynecology, Los Angeles County - University of Southern California Medical Center.
THE CLINICAL EXPERIENCE WITH THE BLEEDING TIME AS A MEASURE OF PLATELET FUNCTION IN PATIENTS WITH SEVERE PREECLAMPSIA
Thomas J. Benedetti, M.D., John C. Hargrove, M.D., and Zane A. Brown, M.O.
Departments of Obstetrics and Anesthesiology, University of Washington
Pregnant patients with preeclampsia are known to have a variety of hematologic
changes which include: hemo concentration, thrombocytopenia and increased production
of fibrin degradation products. In addition, previous work has demonstrated impaired
platelet aggregation in patients with severe preeclampsia. This pilot study was
undertaken to assess the relationship between platelet count and bleeding time.
Materials and Methods
Sixteen patients with severe preeclampsia have served as the study group. Each
patient was questioned regarding the use of aspfrin in the previous week and none
were found to have employed any such compounds. Bleeding time was performed in the
following manner. Blood pressure cuff was applied to the upper arm while the patients
were in the supine position and pressure cuff inflated to 4OnnnHg. A standard bleed-
ing template was then used and a rapid lmn incision was made in the skin of the fore-
arm using an automatic lancet device. Blood was collected from the periphery of the
incision every half a minute until the bleeding ceased. This time was noted and
recorded as the bleeding time. Normal values for this test are between 3 and 8 min-
utes.
Results
Results of the bleeding time are illustrated in the accompanying table. There
is no correlation between the bleeding time and the absolute platelet count. Despite
a platelet count of less than 100,000 in nine patients, only four had significantly
prolonged bleeding time. However, in patients with platelet counts of greater than
150,000 three of the five patients had significantly elevated bleeding. These re-
sults suggest that the absolute platelet count is a poor predictor of platelet func-
tion in severe preeclampsia.
Further studies are needed to
identify the clinical relevance
of these findings. At present
we are reluctant to use conduc-
tion anesthesia in patients
with significantly prolonged
bleeding times and recommend
that this test be done prior
to the use of conduction anes-
thesia in patients with severe
preeclampsia.
0 l
.
n46
100 200 300
Platelet Count Ix lO’I
Title: The Maternal and Fetal Cardiovascular Effects of Epidural Morphine
Authors : Craft, J.B., M.D.; Bolan, J., M.D.; Coaldrake, L.A., M.B.B.S.; Mazel, P., Ph.D. ; Gilman, R.M., M.S.E.E.; Shokes, L.K., M.S.E.E.; Woolf, W.A., B.S.
Affiliation: Departments of Anesthesiology; Obstetrics and Gynecology; and Pharmacology, George Washington University Medical Center, Washington, D.C.
Introduction: The administration of epidural narcotics for pain relief is becoming more widespread following the demonstration of specific opioid receptors within the spinal cord Small doses of narcotics given by this route have been proven to be of value in the relief of various types of pain, causing long-lasting analgesia which is not accompanied by the adverse side-effects commonly seen after epidural administration of local anesthetics (eg. sympathetic block with hypotension, motor block, toxic reactions following inadver- tent intravenous administration). The use of epidural narcotics is therefore currently being evaluated in obstetrics, as its relative lack of toxic side-effects combined with the small dosages which appear to be needed for adequate analgesia, should offer special advantage to both mother in labor and fetus. Using the chronic maternal-fetal sheep model we undertook to study the effects of the administration of 5 mg. epidural morphine on mate nal and fetal cardiovascular dynamics, and acid-base status; und also to measure the maternal and fetal blood levels of morphine.
Method : Six pregnant ewes (gestational age 124-138 days; term 145-150 days) were anes- thetized with halothane and oxygen. A maternal femoral artery was cannulated for measure- ment of arterial pressure; and withdrawal of samples for acid-base determinations and mor- phine blood levels. A maternal femoral vein was cannulated for administration of intra- venous fluids . A Swan-Ganz catheter was inserted via the jugular vein for measurement of central venous pressure and pulmonary artery pressure; as well as for cardiac output deter minations (using the thermal dilution technique). Hysterotomy was performed, and a fetal femoral artery cannulated for arterial pressure measurements, and blood sampling for acid- base studies and morphine levels. A catheter was inserted into the uterine cavity prior to its closure for measurement of intra-uterine pressure. An electromagnetic flow-probe was secured around a main branch of a uterine artery for uterine blood flow measurement. Prior to discontinuation of anesthesia, the animal was placed on its left side and a 19- gauge epidural catheter inserted via the lwnbosacral interspace. Confirmation of the loca tion of the catheter was done by injection of local anesthetic at the conclusion of the experiment.
Results: -- % Change From Control *p<o. 05 All values shown are increases above control unless o&&-wise indicated. **p<o. 01 Minutes from
Injection 15 30 60 90 120 150 180 210 240 - Maternal Arterial Pressure -2.0 0.3 -4.2 -2.4 8.0 1.3 -0.9 -4.3 -4.6 Maternal Heart Rate -1.6 3.2 -5.1* -9.4* -4.5 -5.6 Systemic Vascular Resistance 0.2 -6..1 -7.5 -6.5 0.32 -2.8 Fetal Arterial Pressure -5.1 -4.5 -4.7 -9.3* -2.3 -1.6 Amniotic Pressure 18.6 -2.4 7.1 -2.3 2.6 21.6 Uterine Blood Flow -5.1 -0.5 -5.1 2.7 -8.O* 0.8 Maternal pO2 3.4* 3 h . 2.6 12.04*’ 4.7 ll.O* Fetal pH 0 i . 0.3 0.3 0.2 0.1 0.1 Fetal ~02 -2.0 -4.Cl 1.5 0.6 3.3 5.4 ___~___._ _-.. ---..-. --~ _-.. -.____~_-.._.. .__ Maternal and fetal blood morphine levels will be presented.
-4.4 -4.3 -3.3 -4.9 -13.8 -21.1* -5.7 -4.0 -6.2 3.6 -0.4 4.1 0.6 -4.2* -6.3 4.01 3.6 10.3f 0.3 0.2 0.2 2.4 5.0 5.5
---. --
60
A COMPARISON OF EPIDURAL MEPERIDINE AND BUPIVACAINE FOR THE
RELIEF OF LABOR PAIN. S. Bramwell, W. Hammonds, C.C. Hug,
'2. Najak, Departments of Anesthesiology & Pediatrics, Emory
University School of Medicine, Atlanta, GA 30322, USA
Aim of Investigation: Epidural opiates have been advocated for
pain relief. We compared the analgesic efficacy of epidural
meperidine and bupivacaine in patients in labor at term.
Methods: Fifteen patients in early spontaneous labor received
25 mg of meperidine diluted to 1Oml with normal saline in the
lumbar epidural space. The patients graded their pain on a 0 to
4 scale. Objective ratings of pain were made on a 1 to 7 scale
including the variables of facial expression, bodily movement,
and breathing irregularity. Pain was evaluated before and at 15,
30, 45, 60 and 120 minutes after treatment. Another 15 patients
received lOm1 of 0.125% bupivacaine in the epidural space and
their pain level was evaluated by the same methods. Scanlon
neurobehavioral assessment's here obtained. The data were sub-
jected to analysis by the Wilcoxon Rank Sum Test.
Results: Patients in the meperidine group had higher average
pain scores than the patients in the bupivacaine group in both
objective and subjective ratings. At 45 and 120 min. these dif-
ferences were statistically siqnificant. Neurobehavioral tests
were similar in both groups.
Conclusion: Epidural meperidine in the doses employed is in-
ferior to bupivacaine 0.125% in providing analgesia for labor.
61
FOLLOW-UP OF HYPERVENTILATED NEONATES. C. Brett, M. Dekle, C.H. Leonard, C. Clark, S. Sniderman, R. Roth, R. Ballard, and R-1. Clyman. Mt. Zion Medical Center, Department of Pediatrics, San Francisco, California.
Hyperventilation has been advocated for treatment of newborn infants with pulmonary hypertension; however, there are theoretical harmful effects of hyperventilation on the immature nervous system. From March 1977 to May 1979, 13 infants less than 37 weeks gestation were selected to be hyperventilated cause of severe hypoxemia refractory to conventional mechanical ventilation, i.e., failure to maintain Pa02 > 50 torr with an FiO2 1.0, despite PaCO2c 40 and pH>7.40. Eleven survived, 9 were available for follow-up evaluation. Seven infants had meconium aspiration syndrome, one had HMD, one had Group B strep sepsis. All infants eventually required a decrease in PaC02 to ~20 torr and increase in pH to >7.50 before a change in AaDO became evident. As a group, the 9 infants were exposed to a PaC02 <20 torr for 51.8+11.8 hrs (mean-+SEM), to PaC02 cl5 torr for 11.8k3.3 hrs, to a pH>7.50 for 64.4k18.6 hrs. and to a pH>7.60 for 6.1+2.9 hrs. One infant was lost to follow-up after a normal assessment at 9 months. The other 0 infants (7 AGA, 1 markedly SGA) were at least lh years at the time of evaluation. The 7 AGA infants had a normal developmental quotient (meatilo, range 96-130) by Stanford Rinet or Bayley; the one SGA infant had a Bayley of 89. All 8 had normal neuro- logical examinations. All AGA infants are growing normally. Although only 9 infants with short term follow-up are reported here, these preliminary observations are reassurinq with respect to neurological and developmental outcome following prolonged hyperventilation.
62
oxyhemoglobin Affinity 6 Buffering Capacity in Infants of Diabetic Mothers. Brouillard, R.C.,
Kitrmiller. J.L.&tta, S., Brigham and Women’s Hospital, Boston, ha.
Studies were carried out to determine the oxyhemoglobin affinity and buffering capacity of blood of infants of diabetic mothers (IDH) at dellvery. Cord blood was obtained at delivery and was analyzed for oxyhemoglobin affinity by determining the partial pressure of oxygen at a hemoglobin saturation of 50% (P50). Buffering capacity was determined by CO titration by saturation of fully oxygenated blood with varying CO concentrations wh$le maintaining a constant buffer base, this being an indicator of $ he non-carbonic
buffer system. ISO-PC0 $
titration was performed by malntalning a constant PC0 & varying the buffer base level, hus Indicating the effect of the carbonic and non-car & nit buffer
systems. We found an increased oxyhemoglobin affinity in IDH’s compared to controls, Fig.1.
(P < .O25) as well as a decrease in the respiratory and metabolic buffer values (P < .OS). 2,3-DPC was also measured in the two groups, but was not significantly different. The fall in blood PH on oxygenation (PH,,), with increasing PC02 was greater in IOH’s than controls. Base
excess (BE), was also significantly different (P < .05). There is a significant correlation
between P The oxyh ez?
and the CO2 titration buffer value B’(mEq HCO -/L*PH unit), Fig.2, (r=.B9). globin affinity difference seen in IDfirs is unr ated 1 to gestational age & the
level of red cell 2,3-OPG. The difference in buffer values at this point cannot be accounted for without further investigation.
‘I I
I
Fig.1. Oxyhemoglobin dissociation curves of blood obtained at delivery.
‘LDM, P50=17.9+_1.5. Control (fetal), P50- 22.e2.1, Maternal (Diabetic) P5op 26.321.3, Raternal (Control) PsG-2U.321.7.
10-
*
..*
/. a,
Fig.2. Relation between the respiratory buffer value (6’) and the level of oxyhemoglobin affinity (Pso). B’ aepends on the noncarbonic buffer system, chiefly hemoglobin.
NEONATAL HEART RATE FOLLOWING MATERNAL EYIDURAL ANESTHESIA
Brown, W.U., M.D., Bell, G.C., M.D., Datta, D., M.D., Department of Anesthesiology, Vanderbilt University School of Medicine, Nashville, Tennessee 37232; and Department of Anesthesia, Harvard Medical School, Brigham and Women's Hospital, Boston, Massachusetts 02115.
Introduction. Subtle changes in fetal heart rate variability have been observed following uncomplicated maternal epidural anesthesia. Recent evidence Indicates that local anesthetic drugs have the potential to block reflex heart rate changes. This study evaluates the baseline neonatal heart rate and reflex heart rate responses to various newborn procedures following maternal epidural anesthesia for labor and delivery.
Methods. Thirty-one neonates were studied. Bupivacaine was used
for maternal epidural block in 8 cases, while lidocaine was used in 7 and mepivacaine in 8. Eight mothers were unmedicated. Following birth electrocardiographic electrodes were applied to the baby and the instantaneous heart rate recorded on a strip chart for 12 minutes. During this period the nose was gently suctioned with a catheter (NC), the stomach aspirated with an orogastric tube (OG), and oxygen was briefly blown over the baby's face (02). Baseline neonatal heart rate level, longterm variability (Var) and decelerations were noted. Data were subjected to analysis of variance and chi square tests.
Results. Mean concentration of lidocaine found in umbilical vein blood at delivery measured 1.24 ug/ml (n=3), mepivacaine 1.79 ug/ml (n=5), and bupivacaine 0.12 vg/ml (n=3). Findings for neonatal heart rate are presented in the following table.
Neonatal Heart Rate
Baseline Decelerations croup Level Var NC O(; 0,
Control 170t9* 68?33 3 2 2
Lido 169tl4 65t37 2 2 1
Hcpiv 175r12 57*29 2 4 2
Bupiv 168i11 60*35 2 1 1
*Mean x S.D.
There were no -ignificant differences among the groups for any of the variables studied. Decelerations related to procedures were transient and usually V shaped.
Discussion. L*lat.erual epi:i~~rci 1 anesthesia with either bupivacaine, lidocaine or mepivacainc does n.lt 3pDear to significantly modify the neonate's baseline heir-t raft' ':r bloc-k reflex responses to commonly used clinical procedart!s.
64
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CHI.OKOI’RO::AINE I:OLLOWED BY BlJt’IVACAINi<
FOR ElAl’ERtiAl. l:l’~DIIKAL ANFSTHESIA
Brown, W.IJ., M.D., (then, I,. , b1.1). , IdatkIns, M., t’.P., Krigdr, .I., M.D.) Department of Anesthesiology, Vanderbilt i:nivcrsity School of Medicine, Nashville, Tennessee, 37232
Maternal epidural anesthesia with mixtures of chl~~rnprocaine
and bupivacaine manifests the clinical properties of chloropro-
Caine alone, bupivacaine failing to prolong anesthetic action.
Before the controversy concerning the use of chloroprncainc.
we frequently initiated epidural anesthesia with 3 percent
chloroprocaine taking advantage of the fast onset of action and
the rapid metabolism in the event of intravascular injection.
We would then attempt to maintain the anesthesia with the
longer acting 0.5 percent hupivacaine. However, the subsequent
use of bupivacaine led to a high incidence of unsatisfactory
blocks. This suggested a more profound effect than that
observed with the administration of a mixture of the two drugs.
We therefore prospectively evaluated five cases 1.11 which the
sequence chloroprocainr-hupivacaine was used. The results
and implications will be discussed.
65
Date: .January 21, 1981
Title: In Vitro Evaluation of Antacids
Authors: Hun Taek Chung, M.D., Lloyd F. Redick, M.D. --
Affiliation: Department of Anesthesiology, Duke University Medical Center,
P.O. Box 3094, Durham, NC 27710
Oral premeditation
hazard of aspiration of
with antacids has been recommended to reduce the
acid gastric contents. Gibbs, et al, (1) have shown
that available suspensions are potentially hazardous and suggest the use of
antacid solutions.
We have studied buffer solutions in a hydrochloric acid in vitro model
as suggested by Fordtran, et al, (2). To 100 ml of 0.1 N HCl, 15 or 30 ml
of various antacids were added. The pH was measured at 37O 2 1.5'C with a
Fisher model 230A pH meter, and recorded at 5 minute intervals until stable.
Precipitation and gas formation were noted if present (Table 1).
Sodium citrate was an effective buffer; however, sodium intake may be
a problem in some patients, and magnesium citrate may be a suitahle alter-
nate. Further discussion of the results and observations will he made.
Antacid Solution ~-__ .__--_
10% Mg Sulfate
Manuitol
Antacid Solutions -____
Vol. (ml) pll 5min. 30min. w. Gas -..
30 1.31 1.33 No No
30 1.41 1.42 No No
Maalox 30 6.35 6.56 Yes No
Citrate Magnesia 30 3.06 3.06 No No
Calcium Gluconate 30 2.69 2.83 No No
0.3 N Na Citrate 15 3.52 3.55 No No
0.3 N Na Citrate 30 4.91 4.91 No No
0.3 N Na Citrate 60 5.62 5.62 No No
8.4% N Bicarbonate 30 6.99 7.14 No Yes
References:
1) Gihhs CP , Schwarr % I).], IJvnne .JW: Antacid Pulmonary Aspiraticln in the Dog
Anesthesiology 51:3BD-385, 1979 --__.--__
2) Fordtran .JS, Mnrawski St;, Richardson CT: In Viva and In \!it t-k, Ev;llu;lt inn
of Liquid Antacids, N. Eng. .I Med _ _. ._L -__ ~. 228:923-928, 197'3
66
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Title: Cardiovascular Effects and Blood Levels of Intravenous Fentanyl in the Chronic Maternal-Fetal Sheep Wodel
Authors : Craft, J.B., M.D. ; Coaldrake, L.A., M.B.B.S. ; Balan, .I., M.D. ; kz~.l, I’. , Ph.D.; Gilman, R.kI., N.S.E.E.; Shokes, I,.!!., Y.S.li.I..; Woolf, WA., B.S.
Affiliation: Departments of Anesthesiology; Obstetrics and Gynecology, and Pharmacology: George Washington University Medical Center, WashIngton, D.C.
Introduction: Fentnnyl is a synthetic opioid. with an analgesic potency estimated to be 75 times greater than morphine. Because of its rapid onset and brief duration of action, fentanyl may offer a particular advantage as an analgesic in the patient in labor, as it may alleviate concern about prolonged respiratory depression of the newborn. It was our aim to study the effects of an intravenous bolus injection of 50 micrograms fentanyl on both maternal and fetal cardiovascular dynamics and acid-base status; and particularly its effects on uterine blood flow and uterine tone, both of which directly influence fetal well-being. We were also interested in following hlood levels of fen- tanyl in mother and fetus, to elucidate the extent and rapidity of its transfer across the placenta.
Methods : Six pregnant ewes (gestational ages 124-138 days, term 145-150 days) were anesthetized with halothane and oxygen. Under anesthesia, a Swan-Gans catheter was inserted via the jugular vein for measurement of central venous pressure, pulmonary ar- tery pressure, and cardiac output (using the thermal-dilution technique). A maternal femoral artery was cannulated for arterial pressure monitoring, as well as for withdrawal of blood for acid-base studies and determination of fentanyl blood levels. A maternal femoral vein was cannulated for administration of intravenous fluids and fentanyl. Hys - terotomy was performed via a midline abdominal incision, and a fetal femoral artery was catheterized for the same reasons LLS in the mother. A catheter was placed into the uterine cavity for measurement of amniotic fluid pressure. prior to closure of the abdomen , an electromagnetic flow-probe was secured around a main branch of one of the uterine arteries.
The animals were subsequently allowed to recover from surgery for 24 hours prior to collection of experimental data. After a stable control period of at least thirty minutes SO micrograms fentanyl was administered intravenously to the mother. Following injection, maternal and fetal blood samples were taken at 1,3,5,10,15,30 minutes, and every 15 min- utes thereafter for a total of 2 holkrs, for acid-base and fcntan;,rl determinations. Mat- ernal and fetal cardiovascular dynamics were monitored continuously throughout the experi- ment.
Results : .p- % Change From Control *p/o. 05 ----___
All values shown are increases above control unless otherwise indicated. **p<o. 01
Minutes Since Inject ion 5 10 15 30 45 60 ‘5 90 105 120
Cardiac output c>.s* .l .-‘---------17,7** 14,0* ___ ____-___ _ - ___- ----. 11.5 12.3* 9.2 12.4f 12.7* -K-P
Svstcmic Vascular Resistance -10.7** -9.9 -9.0 -2O.S**-lS.S* -11.6 -6.3 -6.3 -10.0 -13.1
JJterine Blood Flow -10.4* -I?.?* -a:.9 -14.8* -10.6 - 8..1 -11.4 -5.2 - 2.7 - 2.2 Amniotic Pressure 21.5 29.6 - .,- . 4 64.4 62.6 47.8 81.9 01.9 X8.5 96.9 pCO2 ma t erna 1 - .?..l n.4 2.5 il.5 6.a* 4.6 -0.6 0.9 3.9 - 1.5 PO2 illitternal 0.4 0.6 -0.7 - 1.5* 0.2 3.2 1.2 3.1 i. 0 3.8 pCO2 feta I 5.4 2.x I . 0 10.1** 3.8 -0.2 -0.8 2.0 - L.5 - 5.0 pO2 fetn I - 3.2 -12.9* -8.4 - 2.1 5.2 6. 0 t;.2* -1 .H - 0.9 - 4.7
_- _-- --- __ ---.- Maternal and fetal fentnnyl lc\~cls will he presented and correlated with cardio-
respi rntory data. 67
PREVENTION OF HYPOTENSION WITH HYDRATION Charles P. Gibbs, M.D., Lynn Spohr, C.R.N.A., David Paulus, M.D., Raymond Schultetus, M.D., Department of Anesthesiology, University of Florida
Prophylatic measures to prevent hypotension include LUD, prehydration with 1000 ml crystalloid, and I.M. ephedrine. Neither singly nor in combination have these measures proved foolproof. Recently, Mathru et al have added 5% albumin to 1000 ml 05R/L and prevented hypotension in 24 patients receiving spinal analgesia. Although these results are encouraging, the cost of pre- paring 5% albumin solutions is great (approximately $240.00 in our insti- tution). Since Telenko et al have recommended using 1.2% albumin as a resuscitation fluid and since Caritis et al have reconmiended more than one liter of crystalloid to prevent hypotension, we chose to evaluate the effec- tiveness of 1000 ml R/L with 1.2% albumin as compared with 15 ml/kg R/L (approximately 1000 ml) and 30 ml/kg (approximately 2000 ml) for preventing hypotension. Methods: Thirty two patients received epidural analgesia with a variety of local anesthetics. None had received more than a minimal amount of fluid before the test solution was administered. All were ASA class I patients and the fetuses were not compromised. Group I received 15 ml/kg R/L. Group II received 15 ml/kg R/L + 1.2% albumin. Group III received 30 ml/kg R/L. Blood pressures were monitored and recorded every 1-3 minutes via a Sentry automatic oscillometric blood pressure measuring device and recorder. Ma- ternal and umbilical vein gases, Apgar scores, and hematocrits (0 and 30 min) were obtained and recorded. Hypotension was defined as a 20% fall in systolic blood pressure or a systolic pressure below 100 mmHg. Severe hypotension was defined as a 30% fall.
Results: Results are summarized in Table 1.
Table 1. Maternal and Neonatal Results Following 3 Different Types of Prophylatic Fluid Administration.
Grp. I (N=ll) Grp. II (N=lO) Grp. III (N=il)
1100 mnHg or 20% 130%
No. pts. with 1BP
6 (60%) * 4 (40%)
; 1;;;) * +
treated with ephedrine 5 (62%) 3 (50%) 2 (40%) Apgar 17:6 1 pHuv<7.25 1 : ; Hct before fluids 33.6+3.2 Hct 30 min after fluids 30.5E2.6
34.8+5.6 # 29.1+6
33.6+3.4 # 26.2z2.8
+ ~~0.05 II vs III (Fisher's Exact) # p-~~O.01 Student's paired t test * NS 1 vs II and I vs III
There was no difference in the occurrence of hypotension among the three groups. However, severe hypotension occurred less frequently in group III than in group I (p-cO.05). Three patients each in groups I and II developed hypotension below 80 mHg. None developed hypotension as low as 80 mmHg in Group III. Conclusion: Hypotension cannot be predictably prevented by any of the three solutions -tested. Although our data indicate that there is no significant advantage in using either 1.2% albumin in R/L or 30 ml/kg of R/L to prevent hypotension, a trend seems to exist which may become more evident with larger numbers of patients. Moreover, the degree of hypotension is less when larger volumes of crystalloid are used.
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ACTION OF LOCAL ANESTHETICS ON NON-GRAVID UTERINE ARTERIES
Jonas Gintautas, M.D., Ph.D. and Barry J. Kraynack, M.D.
Anesthesiology Research Laboratories Texas Tech University Health Sciences Center
Lubbock, Texas
We studied in vitro effects of lidocaine, chloroprocaine and
bupivacaine on non-gravid human uterine arteries.
Four mm arterial rings were placed in a 40 ml bath, containing
a Tyrode Buffer solution and continuously aerated with 95? 02 and 55;
CO2, maintaining pH = 7.3 and temperature 37OC. Initial tension was
2 grams and stabilization period was 60-90 minutes.
Dose response curves were obtained on all drugs used. Lidocaine
caused dose dependent vasoconstrictlon while the other two agents show
a tendency to vasodilate the arterial rinqs.
Clinical relevance of these findings to obstetric gynecologicai
anesthesia will be discussed.
71
BRAINSTEM EVOKED RESPONSE IN NEONATES
Sinai Hospital of Baltimore
Baltimore, Maryland
Phillip J. Goldstein, M.D., A. Krumholz, M.D., J. Felix, M.D. D. Shannon, Ph.D., K. Harris
Departments of Obstetrics, Pediatrics, Neurology, Rehabilitative Medicine
The Auditory Brain Stem Evoked Response (BSER) demonstrates progressive decrements in latency in normal maturing premature infants. Waves I, III & V decrease in latency, 1.1, 2.2, & 2.0 msecs respectively from 31 weeks to term. Another age dependent alteration in the BSER is the frequency of the appearance of waves II & IV.
We have characterized the similar physiologic auditory pathway in neonatal Sprague-Dawley rat pups.Neonatal rat, neurophysiologically, day O-31 represents approximately 30 to 40 weeks human gestation. Latency decreases as a function of neonatal age, as in humans, although the anatomic generators are slightly different. Waves I, II, III & IV decrease by 1.3, 4.2, 6.1 & 8.5 msecs from neonatal day 12 to day 31 respectively.
Brain sections from representative neural generator sites have been studied. Anatomic correlation of the physiologic alterations demonstrafes increase in axon size and cell number coupled with marked increases in myelination. This change proceeds in a caudal to rostra1 sequence.
We have now characterized a change in BSER latency as a function of core body temperature. All wave latencies increase in speed as a function of increasing body heat and are slowed by body cooling, a phenomenon heretofore not reported. The response is linear in the physiologic range, is most marked in wave V and within each neonatal period. This data casts suspicion on the expected stability of the BSER and emphasizes the need for standardization at time of testing.
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Comparison of the Effect of 4 Hypotensivc Agents in the Pregnant Ewe
Rober’t Hodgkinson, M.D. U.T.H.S.C. at San Antonio
Under halothane induced and maintained general anesthesia the following monitors were inserted into 6 ewes 120 days pregnant (term 147-150 daya).
(1) Fetal femoral arterial catheters for recording arterial pressures, pulse and blood gases
(2) Maternal femoral arterial and vefnous catheters (3) Amniotic cavity catheter (4) Flow probe around uterine artery supplying pregnant horn (5) Swan Ganz catheter for measuring P.A.P., P.W.P., C.V.P. & C.O.
At least 24 hours later and after a half an hour stablizing period during whiclr time all recorders were running (control values), a phenylephrine drip was run into the maternal femoral vein using a Harvard pump at such a rate as to ker%p the maternal arterial pressure 202 above normal. After half an hour 1 of 3 drugs (nitroprusside, nitroglycerine, or trimethaphan) was Injected using a Harvard pump at such a rate as to reduce the maternal arterial pressure to control values. Each drug was injected for half an hour during which time maternal arterial pressure (MAP), pulmonary arterial pressure (PAP), pulmonary wedge pressure (PWP), cardiac output (CO), and central veinous pressure (CVP), we’re measured. Fetal arterial pressure (FAP), pulse rate and blood gases as vel.1 as uterine blood flow were also recorded. A resting period of half an hour followed. During this time all record- ings were continued and the only drug flowing was phenylephrinc which was adjusted so that the maternal arterial pressure was +20 of control values. The next of the three drugs was then run for half an hour to reduce the maternal arterial pressure to normal. After a further resting period of half an hour the third drug was injected. After all three drugs had been given and a further resting period of half an hour hydralazine was injected to reduce the arterial blood pressure to normal. The three short acting drugs were administered to the sheep in the form of a Latin Square design. Hydralazine being a long acting drug could only be admin- istered as the last drug to each sheep. Results which have still to be analysed statistically will be presented as percentage change (? SE) from control values for MAP, HR, CO, total peripheral resistance (TPR), UBF, FAP, HR and blood gases. The study is still in progress.
73
MENDELSON'S SYNDROME? Robert Hodgkinson, M.D.
U.T.H.S.C. at San Antonio
Acute Respiratory Distress Syndrome (ARDS) developing in a patient with previously normal lungs is a nosological pigeonhole containing cases resulting from shock, sepsis, viral pneumonitis, hypoxemia, head injury, drugs, aspiration, pneumonia etc. The common pathway appears to be increased capillary permeability. Occuring after general anesthesia in obstetrics it is usually ascribed to Mendelson' Syndrome even if the anesthesiologist deftly intubates without seeing gastric contents, cricoid pressure was applied until the endotracheal cuff was inflated, the patient extubated fully awake, antacids given and other precautions taken.
In the 57,450 deliveries including 5,068 under general anesthesia at the U.T.H.S.C. at San Antonio here have been 3 deaths from ARDS; 2 associated with but
clearly not due to general anesthesia.
Case 1. A 34 year old, Para 4004 was admitted for a cut lip. There had been no
prenatal care and she was without symptoms until approximately 8 hours earlier. A history of vomiting or seizure was denied. The patient was confused, dyspneic. her blood gas on room air was pH 7.36, Pa0 ,,2 43, PaCO 23, base excess -11 and her chest X-Ray showed a complete "white out. The arter al z pressure was 184/110 to 212/112, there was 4 plus albumin and 2+ reflexes. A baby with an Apgar of 9 at 1 and 5 minutes was delivered by cesarean section under general anesthesia. On 100% oxygen and 10 cm PEEP her blood gas improved during anesthesia to pH 7.28, Pa02 118, PaC02 32, and base excess -11. An initial CVP of O-5 and PWP of 5-9 excluded right or left sided heart failure. The patient died in the ICU 5 days later having required increasing degrees of PEEP. At autopsy both lungs were completely consolidated. There was no pathological evidence of hypertension or cause for her condition.
Case 2. A 29 year old primigravida who had no prenatal care was admitted in a diabetic, ketoacidotic, stuporose condition with a dead fetus. Her relatives
stated she had neither seized nor vomited while stuporose. An X-Ray showed no pulmonary infiltrates. Her leucocytes count was 23,900 (N.81%). She was intubated awake and after her diabetes and acidosis had been treated transfered to ICU. No cause was found for her leucoytosis. The patient remained intubated with positive pressure ventilation. On the second day her arterial pressure rose to 170/100 - 110 from its previous level of 90/70 and then was 3+ albuminuria. On the third day
X-Ray showed bilateral infiltrates. A cesarean section was performed under general anesthesia. Increasingly severe ARDS and DIC resulted in her death on the seventh day. Autopsy showed bilateral congestion and edema of the lungs with early hroncho- pneumonia. Other organs were essentially normal.
Case 3. A 17 year old primigravida was admitted in coma and gave birth to a 700 gram fetus. Death occurred 36 hours later and autopsy showed severe ARDS. A history of the ingestation of tolbutamide, codeine, barbitrlratrs, aspirin and other medication was obtained.
References _-----
1. A rcplrrt on an c‘nquirey into maternal deaths in Scotland 1972-1975 Edinburgh HFtSO 1978
2. Baird D. Combined Textbook Obstetrics and Gynecology 8th Edition Edinhllrgll 1969 p 335
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CONTTNUOUS INFUSION FOR LUMBAR EPIDURAL ANALGESIA DURING LABOR
James D. Jones, II, MD., Akira Iwane, MD, and Robert Hellman, MD Department of Anesthesiology, Washington University School of Medicine
St. Louis, Missouri
Clinical evaluation of a low-dose continuous infusion technique used for
lumbar epidural analgesia during labor was undertaken. An Auto-Syringe (R)
Model AS-2F infusion pump was employed for continuous infusion of a local
anesthetic into the epidural space. The compact size, light weight, dura-
bility and accuracy of this unit was felt to be advantageous. The objective
of this study was to assess the clinical efficacy of
compared with the intermittent Injection technique.
Adaptability of the equipment and manageTent of
this technique as it
the parturient will be
discussed.
Comparison was made with a control group using the intermittent injection
technique. Principle advantages of the continuous infusion technique included:
(1) a smoother course of analgesia; (2) less cephalad spread of the motor block
level which can aid more effective expulsive efforts in the second stage; and
(3) less time required of the attending anesthesiologist once the block is
established.
PUMP INFUSION DETAILS
Tnitial loading dose: 5-g ml 0.375% bupivacaine
Dose rate: 5-8 ml/hour (18.75 - 30 mg)
Mean dose per hour: 40.74 mglhour !. 10.28 S'.D.
Labor time: 3.4 hour + 1.3 S.D.
INTERMITTENT IN.IECTTON DETAILS ____ -
Initial loading dose: 5 - 8 ml 0.3752 bupivacaine
Mean dose par hour: 32.1 mg/hour ? 11.1 S.D.
Lahnr time: 2.69 hour + 1.47 s.n.
75
NEUROLOGICAL LOSS ASSOCIATED WITH VAGINAL DELIVERY: REPORT OF TWENTY-EIGHT CASES
Thomas H. Joyce, III, M.D., Umeshraya T. Pai. M.D. and Dolores El. Diaz, M.D.,
Department of Anesthesia, University of Cincinnati Medical Center, 231 Bethesda Avenue, Cincinnati, Ohio 45267, U.S.A.
Twenty-eight patients delivered at the University of Cincinnati between
1976-1980 developed a well circumscribed area of hypesthesia on the lateral
aspect of the thigh. This hypesthetic area resolved with the return of normal
sensation in 4-12 weeks with a mean of 6 weeks. The pathonomonic history
common to all patients was a tingling or a warm-hot poker sensation radiating
from the buttock into the thigh in the late-first stage of labor or early-second
stage of labor (during pushing). Four patients also noted this sensation
during forceps delivery, although perineal
episiotomy. Dermatome involvement was the
All patients tended to be short of stature
anesthesia was sufficient for
fourth lumbar almost exclusively.
and 20-30 pounds over ideal weight.
This may suggest mid-pelvic soft tissue dystocia accentuating the occiput
posterior position as a contributing factor.
Age 18 (23) 30 Height (in) 49 (53) 55 Weight (lbs) 155 (168) 182 Parity 0 18 Parity 1 8 Parity 2 2 Position OA 12 Position OP 16 Spontaneous rotation OA 4 Forceps OA 8 Outlet forceps 17 Fetal weight (lbs) 6 (7.10) 9.? Anesthesia - none 3 Anesthesia - local 6 Anesthcsi;l - spinal 4 Anesthesia - epidural 15
76
CINSCORE - AK OBSTETRICAL RECOVERY ROOM EVAl.UATI(iN TOO1
7
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3
3
3
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‘Thomas Il. Joyce, LII, M.D., Department of Anesthesia, Uniters ity of Cincinnati Medical Center. 231 Rethesda Avenue, Cincinnati, Ohio 45267, U.S.A.
For the past two years, the CINSCORE has been used at the University of
Cincinnati Obstetrical Speical Care Unit Recovery Room. The score has provided
an improvement in nursing observations and recorded (Medico-legal) patient
charting. More importantly, it has improved MD-RN communications and early
MD patient observation of uterine atony, missed vaginal/cervical Lascerations,
early and/or delayed recovery from anesthesia, and early dismissal from a busy
recovery room when appropriate. I
CRITERIA 1 “Ir*y_&JQ*.w 75 go 120 160 loo, c CON~SS Fully awake 2 NWWNO NOTE8
Amusable on calhng 1 1 Not reapondmg 101 I I I I I I I 1 1
4 INVOLUTIHQ UTERUS Firm 2 Ftrm with massage 1
N NADAR FUNOUS At umbiltcus 1 Displaced 0
N NEUROMUSCULAR Mom 4 extremities on order 2 AcTivlw Move 2 extremities on order 1
1 Move 0 extremitiw on order 0 S SENSATION Normal 2
None below pubas 1 None below xlphold 0
C CIRCULATION BP lcX?O mmtig 2 Admission 2 OPti mmliq f. Admrsslon 1
1 BP,31 mmliq i Admission 101 I I I I I I I I I 0 OUTPUT ON PADS 1 Scant 2
I Moderate 1
II RESPIRATION I Heavy lOI I I I I I I I I I
Deep brealhing or cough 2 Ow+nwa 1
E EPISIOTOMY 1 Apnea lol I I I I I 1 I I I I Intact mlminal edema 121
Moderate edema mtact
I I I I I I I I I
!I
TOTAL w I 1 I I I I I I 1-l
77
TEXAS TECH UNIVERSITY HEALTH SCIENCES CENTER DEPARTMENTS OF ANESTHESIOLOGY, OBSTETRICS AND INTERNAL
MEDICINE - LUBBOCK, TEXAS, 79430
EISENMENGEK'S SYNDROME IN PREGNANCY: CONTINUOUS EPIDURAL ANESTHESIA FOR ELECTIVE CESAREAN SECTION
. . AYNACK. M D . ., J.A. SPINNATO, M.D., M.H. COOPER, M.D.
EISENMENGER'S SYNDROME (ES) IS THE PRESENCE OF PULMONARY
HYPERTENSION AT OR NEAR SYSTEMIC LEVEL, OWING TO A HIGH
PULMONARY VASCULAR RES I STANCE WITH REVERSED OR 81 DI RECT I ONAL
SHUNT AT AORTOPULMONARY, INTERVENTRICULAR OR INTERATRIAL
LEVELS. ITS OCCURENCE IN PREGNANCY IS ASSOCIATED WITH A
MATERNAL MORTALITY RATE OF so%, WHILE MORTALITY WITH CESAREAN
SECTION IS b?.';%. WE
OF A PREGNANT PATIENT
BY ELECTIVE CESAREAN
EPIDURAL ANESTHESIA.
CESAREAN SECTION IN A
REPORT HERE THE SUCCESSFUL MANAGEMENT
WITH EISENMENGER’S SYNDROME DELIVERED
SECTION, CONDIJCTED UNDER CONTINUOUS
To OUR KNOWLEDGE, THIS IS THE FIRST
PATIENT WITH ES SUCCESSFllLLY CONDUCTED
UNDER CONTINUOUS EPIDURAL ANESTHESIA- THE ANTE-, INTRA- AND
POSTPARTUM MANAGEMENT OF THE PATIENT WlLL BE PRESENTED-
OUR MANAGEMENT OF THIS PATIENT AND A REV1 EW OF THE
LITERATURE SUGGEST THAT THE FOLLOWING MAY tiELP SECURE MATER-
NAL AND FETAL SURVIVAL:
1) A MULTI-DEPARTMENTAL APPROACH INCLUDING OBSTETRICIAN,
CARDIOLOGIST AND RNEsTHEsIoLoGIsT;
2) AGRESSIVE ANTE-, INTRA- AND POSTPARTIIII MANAGEMENT WITIt
INVASIVE MONIToRING SYSTEM;
3) CESAREAN SECTION MAY BE AN ACCEPTABLE tfETHoD 0F DELIVERY;
4) ~PIDURAL ANESTHESIA IS AN ACCEPTABLE TECHNI~IIE RE(;ARD-
LESS OF THE ROIITF: OF DELIVERY.
Developmental Pharmacology
Poster Session - No
POTENTIATION OF MAGNESIUM INDUCED NEUROMUSCULAR BLOCKADE BY GENTAMICIN. Charles S. L'Honvnedieu, Deborah A. Nicholas,William P. Jones, ThornasK- Nelson, Patricia M. Huber. Univ. of Texas Medzal Branch, Galveston and Univ. of Texas Medical School, Houston, Depts. of Anesthesiology and Pediatrics.
Aminoglycosides have been reported to precipitate paralysis in
myasthenia gravis, infant botulism, and competitive neuromuscular
blockade. We investigated the effect of gentamicin on magnesium
induced neuromuscular blockade in the rabbit. Three kilogram male
rabbits were anesthesized with sodium pentobarbital, intubated and
mechanically ventilated with 100X oxygen. Arterial and venous access
were obtained via ear blood vessels. Blood pressure, arterial blood
gases, end tidal CO2 rectal temperature, and muscle twitch height were
recorded. Baseline serum levels of Mg++, Ca++, and gentamicin were
collected. Mg++ was administered by continuous I.V. infusion to
maintain a 502: depression in control twitch height for 30 minutes.
Gentamicin, 2.5 mglkg, was given I.V. and an additional 10-20:.
depression in twitch height was recorded. Control and experimental
data follow:
Baseline
Control
Significance I Cat+
10 + 2.0
6.35 2.8
P' .025
Mo++
2.1
6.15.67
p < .025
Gent. Muscle Strength * "! of control
----
1.03 + 2.5 50
13 + 4.7 34.6
p < .Ol p < .Ol
--__
Gentamicin given in clinical doses will potentiate a preexisting
magnesium induced neuromuscular blockade.
79
80
SODLUM BICABBirNAiE AS AN URAL ANTACID
Henry S. Lim, M.D. and P. L. Tan, M.D., Department of Anesthesiology, University of Chicago, School of Medicine, Chicago, Illinois
In obstetrics and surgical emergencies, nothing short of forceful evacu-
ation of gastric content would empty the stomach in short time and there-
fore, an oral antacid still remains to be the most effective method in
neutralizing existing gastric acid and protecting the patient from acid
aspiration pneumonitis. An ideal oral antacid must be clear liquid,
effective with small volume, fast acting with no side effects and free of
pulmonary damage when aspirated. Sodium bicarbonate injection, D.S.P.
seems to be such an oral antacid and we reported its effectiveness to this
society two years ago.
This is a report on our extended study reaffirming its effectiveness on
obstetric patients when given just prior to induction of general anesthesia.
Flavored 10 ml of sodium bicarbonate solution were administered orally
3-20 minutes before the induction of general anesthesia to the patients
who were undergoing emergency and elective c-sections. Immediately following
intubation, total volume and pH of gastric fluid were measured via N-C tube
and gastric fluid was returned to the stomach. pH of gastric fluid was
measured every 3U minutes thereafter till the end of surgery. Total volumes
of gastric fluid ranged from 15 ml to 85 ml not counting the volume ot
NaHCO3 given. pH of gastric fluid was above 7.00 on ali patients (25 cases
to this writing) and remained high for at least 90 minutes. Serum electro-
lytes studies showed no rise in serum sodium at 30 minutes following NaHCOj
administration.
It is concluded that sodium bicarbonate injection, U.S.P. is an effective,
fast acting, clear liquid oral antacid with no side effects and capable ot
raising gastric fluid pH to safe level with very small volume. Its effect
on animal lung tissue when aspirated is currently underway.
THE EFFECT OF MATERNAL GLUCOSE INFUSION ON BREATHING MOVEMENTS IN HUMAN FETUSES WITH INTRAUTERINE GROWTH RETARDATION
E -z- R. Luther, M.k, K. Scott, M.D., A. Allen, M.D., D. Stinson, M.D. and J. H. Gray, R. N., Division of Perinatal Research, Department of Obstetrics and Gynaecology, Dalhousie University, Halifax, N.S.
Episodic, rhythmical fetal chest wall movements (FBM) can be observed and
recorded in humans using real time
fetal ~02 will abolish FBM's. The
spent exhibiting FBM's in response
Methods: Forty-nine patients
ultrasound imaging. In animals, decreased
healthy human fetus will increase the tine
to maternally administered glucose.
suspected of intrauterine growth retardation
(IUGR) were studied to determine the amount of baseline FBM activity and the
response to maternally administered intravenous glucose when compared to normally
grown fetuses and normal controls. Potential or known factors influencing FBM's
were rigidly controlled, such as time of day, maternal position, drugs and
smoking. FBM's were observed and recorded for onqhour at fasting maternal
blood sugar levels; then glucose was administered to maintain maternal sugar
levels in the high physiological range and the recording was continued for
another one and one half hours. The amount of TBM was expressed as the percentage
of time the fetus was seen to exhibit this activity during each thirty minute
observation period. The study cases were divided into three groups depending
on the baby's weight and gestation at the time of delivery.
Group A - Greater than the 10th perceatile
Group B - Between 3rd and 10th percentile
Group C - Less than the 3rd percentile
Results: All study and control groups showed a significant increase in
the amount of FBM activity during the glucose infusion. During the two 30-
minute intervals of the fasting phase and for the first 30 minutes after
starting the glucose infusion, there were no significant differences in the
amount of FBM's among the study and control groups. During the final hour of
the glucose infusion, the controls and groups A and B did not differentiate one
from the other, but the severe IUGR group (Group C) showed significantly less
FBM activity (p d.003).
These data show that the amount of FBM activity in IUGR fetuses is not
different from normal when the mother is fasting. However, the increase in
fetal breathing activity in response to maternally administered glucose Is
less in fetuses with severe IUGR.
81
ISOFLURANE ANESTHESIA FOR COMBINED CAESAREAN SECTION AND EXCISION OF PHEOCHROMOCYTOMA. George D. Lyon, M.D. , Patricia F. Norman, M.D., and Roy D. Wilson, M.D. The Department of Anesthesiology, University of Mississippi Medical Center, Jackson, Mississippi, 39216
One hundred and twenty-eight cases of pheochromocytoma occurring during
pregnancy have been reported, but in only 42 was the diagnosis made prior to
delivery. Failure to do so resulted in an alarming maternal mortality of 58%
and a fetal mortality of 55%. Of the 42 patients diagnosed antepartum, 15
underwent combined Caesarean section with resection of the tumor and in only
6 was the anesthetic management a part of the case report.
We will present details of the anesthetic management of a 25 year old black
female undergoing combined Caesarean section and resection of a pheochromocy-
toma with a minimum of polypharmacy. Two unique features of this case were
the pre-anesthetic use of a Swan-Ganz catheter for monitoring of cardiac
filling pressures, cardiac output and total peripheral resistance as well as the
use of isoflurane as the primary anesthetic agent. Both mother and infant
tolerated the procedure well and recovered uneventfully.
1 BP CVP PCW CO TPR* - ---__
Pre induction 160/90 6 0 8.0 1150
10 min. post-delivery 133174 7 5 12.7 650
Palpation of tumor 160/96 8 9 11.7 900 -
Post-excision 122/62 11 5 10.6 600
* in dynes/second /cm5
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AUTHORS:
AFFILIATION:
TITLE:
R. McKenzie, M.D. and R.K. Wadhwa. M.D.
Dept. of Anes., Magee-Womens Hosp., Univ. of Pittsburgh,
Sch. of Med., Pittsburgh, Pennsylvania, 15261
ANTIEMETIC EFFECTIVENESS OF INTRAMUSCULAR VISTARIL COMPARED
INTRAMUSCULAR DROPERIOOL IN PATIENTS UNDERGOING THERAPEUTIC
ABORT IONS
WITH
We compared the antiemetic effectiveness of hydroxyzine hydrochloride
(Vistaril) with droperidol (Inapsine) and a control series in 150 healthy
patients who received a standard anesthetic without premeditation in a double-
blind randomized clinical trial.
METHOD: At 15 minute intervals for three hours after operation, the patient's
vital signs, degree of sleepiness, incidence of nausea, retching or vomiting
and any other complications were recorded. A Trieger Motor Test was performed
before operation and repeated at one hour intervals after operation.
RESULTS: The incidence of nausea and/or vomiting, and/or retching was 56% in
controls, 44% for the droperidol group and 10% for the hydroxyzine hydro-
chloride group. Extensive statistical analysis demonstrated the comparability
of the three groups with respect to age, weight, incidence of preoperative
morning sickness, incidence of previous nausea or vomiting with past
anesthesias and duration of anesthesia.
CONCLUSION: Hydroxvzine hydrochloride 100 mg It4 given after induction of
anesthesia reduced the combined nausea/vomiting/retching rate more effectively
than IM droperidol for patients undergoing therapeutic abortions with a
standard nonpremedicated anesthesia technique.
VASCULAR AND EXTRAVASCULAR CONCENTRATIONS OF HUMAN CHORIONIC GONADOTROPIN
(hCG), FOLLICLE STIMULATING HORMONE (FSH), AND PROLACTIN (PRL) IN NORMAL
TERM PREGNANT WOMEN.
G. Rodney Meeks, Neil Whitworth, James Unger, John Morrison, Samuel Marynick,
and Patricia Norman, Department of Obstetrics and Gynecology, University of
Mississippi Medical Center, Jackson, MS 39216.
Normal patients (N=8) undergoing elective repeat cesarean section were studied
to determine, simultaneously, concentrations of hCG, FSH, and PRL in cerebro-
spinal fluid (CSF), maternal serum, fetal cord serum, and amniotic fluid.
Specific criteria for selecting normal patients were adhered to in order
to reduce extensive variability in hormone values. These were: 1) gesta-
tional age 37-40 weeks, 2) body weight < 175 lbs, 3) blood pressure < 140/90,
4) gravidity > 1 but < 4, and 5) patients with endocrine aberrations or other
major medical problems were excluded. Hormone concentrations were determined
by radioimnunoassay and are reported below as the x + SEM.
Maternal Serum
FSH (mu/ml) hCG (mlJ/ml)
1.6 f 0.2 5805 + 637
PRL (ng/ml) (N=7)
235 f 32
Cord Serum 1.5 +_ 0.3 37 + 6 195 f 27
CSF 2.4 f. 0.4 39 + 6 26 -+ 1
Amniotic Fluid 2.0 +_ 0.3 162 + 37 1254 + 341
FSH concentrations were low in all fluid compartments and may reflect negative
feedback of high estrogen levels during pregnancy. The FSH levels in mater-
nal serum and CSF were similar. By contrast, hCG and PRL were considerably
higher in maternal serum than CSF. These values are unique since they com-
pare the respective hormone concentrations in different fluid compartments
of the same patient.
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THE EFFECTS OF MATERNAL DIABETES CONTROL ON FETAL LUNG MATURITY ASSESSMENT.
John C. Morrison, Philip M. Farrell, Michael J. Engle, Debbie M. Menzel,
Stavros G. Douvas, Neil S. Whitworth, Pamela G. Blake, Department of Ob/Gyn,
University of Mississippi Medical Center, Jackson, Department of Pediatrics,
University of Wisconsin, Madison.
A mature L/S ratio (>2.0:1) equates well with the absence of neonatal
respiratory distress syndrome (RDS) in uncomplicated pregnancies. However,
in patients with diabetes mellitus there is evidence that a mature L/S ratio
may be found in offspring who develop RDS. This study involves the measure-
ment of phosphatidyl glycerol (PG) as perhaps a better assessment of the true
risk of RDS. The L/S ratio and PG analysis was performed in 69 patients with
insulin dependent diabetes (Class 6, 0, or D). In the normal group, 25 pat-
ients had an L/S ratio that was immature and in none of these patients was PG
present. Among the remaining 44 patients the L/S ratio was mature and 11 of
these demonstrated the presence of PG. In contrast, six patients with diab-
etes mellitus demonstrated immature L/S ratios and had no PG while the 23
diabetic patients with mature L/S levels revealed only two cases with PG.
Therefore, the percentage with PG present even when the L/S ratio is mature
was substantially less in the diabetic group. These data suggest possible
subtle alterations in biochemical or metabolic pathways concerning the forma-
tion of PG at cellular level in diabetic patients.
EFFECT OF INTRAVENOUS FLUIDS CONTAINING VARIOUS CONCENTRATION OF GLUCOSE ON MATERNAL AND FETAL BLOOD GLUCOSE LEVELS
Alfred T.C. Penq, M.D., Haider H. Shamsi, M.D., Louis S. Blancato, M.D., Frank A. Chervenak, M.D., Jose Castro, M.D.; Departments of Anesthesiology and Obstetrics & Gynecology; St. Luke's_Roosevelt Hospital Center; New York, New York.
Intravenous loading with crystallofd solution prfor to epidural anesthesia for cesarean section is mandatory to prevent hypotension. Currently available solutions either contain too much glucose or they contain no glucose. Mass- ive maternal glucose administration is potentially detrimental to the new- born. Total absence of glucose from the fntravenous solution is also undes- irable, as fastfng hypoglycemia is a comnon occurrence in pregnancy. There is a need for a solution which may provide optimum glucose levels both in maternal and fetal blood during rapid infusion. Patients were randomly assigned to receive Rin er's lactate in 5% dextrose (Group A), or Ringer's lactate in 1% dextrose 9 Group B), or Ringer's lactate (Group C) intravenously for rapid hydration prior to inductlon of epidural anesthesia. Total amount of solutions infused prior to parturition were ranging from 900 ml to 1500 ml. hydration and at delivery.
Maternal serum glucose was measured before Utiflical cord blood was sent for
P02, base excess and osmolality determinatfons. glucose, pH,
Results: Fasting maternal blood glucose levels ranged from 55-102 mg% (mean 744 mg). The three groups demonstrated significantly different (P<O.OOOl) blood glucose levels at delivery. In Group A, levels ranged from 215 to 550 mg% (mean 341.4 + 90 mg%), Group B from 81 to 152 % Group C from 37 to 87 mg% (mean 64.3 t 16.0 mg% "4
(mean 124.6 + 22.5 mg%) and . The total aiiiount of infused
fluid and the duratfons of infusion we‘re comparable in all three groups. Umbilical artery blood glucose approximated those of the maternal blood in all
9 roups. Umbilical arterial pH In Group A was lower than Group B (P<. .05) 7.25 20.02 versus 7.38 + 0.04). Umbilical arterial base excess of group A
and Group B were -6.8 + lT5 mEq/L and -5.125 + 0.99 mEq/L. (Pc.02). All patients In Group B marntafned maternal and frtal blood glucose levels within optfmum range until delivery. Therefore, we conclude that the use of 1% dextrose solution can prevent dehydration without causfng hyperglycemia nor hypoglycemia. Since amount of solution needed to prevent and correct hypotension varled in wide range, 1% dextrose solution proved to be most feasible for rapid administra- tion. Further results and neonatal responses will be discussed at the time of presentation.
TABLE 1 Maternal and Fetal Bloodse Levels, pH and Base Excess
fn Each Group Patient Glucose
Umbilical Artery
* z$$ll)W 3.5; & (;I* :;$o.; [;)*
c" 53 T 9.2(6)* 7:27 F D:O3 6) -5:3 Tl:O (6 (Group A received 5% dextrose in Ringer's lactate; Group B received 1% dextrose In Rin9er's lactate; and Group C received Ringer's lactate.) The values are the mean + so. The number in parenthesis is the number of observations. * = P ('.05 and ** = P c.001. (Unpaired 2 - tailed t test between Group A and Group B; and between Group B and Group C for significance.)
86
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SCREENING TERM LGA NEONATES FOR HYPOGLYCEMIA. Malini Satish, Gerald - Katzman, J. Williams, Jose Urrutia, P.L.S. Anna, Irwin Weinfeld, Sidney Kripke, Venkatesan Krishnan, Medical College of Ohio, The Toledo Hospital, Dept. of Ped., Toledo, Ohio.
Term large for gestational age neonates are at increased risk for hypoglycemia. It was postulated that identification of term LGA newborns by the Portland Intrauterine Growth Curve as opposed to the Colorado Intrauterine Growth Curve would allow for the classification of a lesser number of neonates as LGA but would iden- tify the LGA neonates at risk for hypoglycemia. We reviewed retro- spectively the charts of 100 inborn neonates born from August through October 1980 who plotted as LGA (wt. >gOth %tile) on the Colorado Chart. 61 of these 100 Infants were LGA on the Portland Chart. All 100 neonates were screened for dextrostix values less than 45 mg.% in the first two hours of life. Of the 17 neonates found to have dextrostix <45 mg.%, 15 had stat quantitative B.S. performed. All 15 neonates were symptomatic with tremors and jitteriness. 11 out of these 15 neonates,had a B.S. <40 mg.%, requiring imnediate treatment. All 11 hypoglycemic neonates were identified as LGA on the Colorado Graph whereas only 7 of these 11 neonates were identified by the Portland Graph as LGA. We con- clude that in our population the Colorado Graph seems to be a better tool than the Portland Graph in identifying term LGA neo- nates at risk for hypoglycemia.
87
GENTAMICIN KINETICS IN VERY LOW BIRTH WEIGHT NEONATES. Malini Satish, Tom Thompson, Venkatesan Krishnan, Gerald Katzman, Jose Urrutia, Irwin Weinfeld, Sidney Kripke, P.L.S. Ana. Medical College of Ohio, The Toledo Hospital, Dept. of Peds., Toledo, Ohio.
Gentamicin kinetics were studied in 12 neonates of gestational ages (GA) (34 wks. (27-34 wks.), of birth weight (700-1500) and compared to 5 neonates of GA > 34 wks. (2440-4890). Timed peak and trough levels were drawn following the first dose of Gentamicin of 2.5 mg/kg IV over one half hour. All determinations were done in the first week of life.
Elimination Half life G.A. #Neonates Volume Dst.(Vd) Constant(Ke) (tL,)hrs. -
x S.V. x S.V. 1 S.V.
<34 wks. 12 0.43 0.03 0.018 0.0003 10 7.84 >34 wks. 5 0.29 0.0024 0.108 0.0022 7.5 12.25
t
student 't' test t15= 18 9.76 3.16 p value <.OOl <.OOl <.Ol
We conclude that during the first week of life in the neonates ~34 wks. G.A. the Vd is significantly higher, Ke is significantly slower and t"Z is slightly longer than the neonates of > 34 wks. G.A. We found no relationship between half life of Gentamicin and Serum BUN and creatinine values. vals.
This has obvious clinical implications in deciding dosage inter-
88
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Title: The Measurement and Hagr.ifude of L&a: Epidural Prar.:,~n
Authors. Ying-Kar. Tien, M.D. and Gerald Edelstein, M.D.
Affiliation: Department ot Anesthesiology. U. of Oregon Healr!~ Crir::_c Ce;.:+:,
Portland, Oregon.
Identification of the epidural space is often based cn the pen<,1 ali\ aclr; re.l
premise that the epidwal pressure (EP), whethe? real OT art:factuai, is lwFatj-.r
Uost fPs previously reporft.3 were onlv a few cri HZLi beloK zero, ar.; L’PW detcr~~I~i?l:
by using measuring systems that contained air in sor~e part of the sy:ier. e.g., t?.~
needle or the connecting tube. Since the epidural space is a small or potential
space, air in the measuring system would tend to reduce ch$ vagnitu.3.. of the measured
EP. Using a measuring system that is complerely liquid-filled, from needle fir tc
pressure transducer. we have recorded EP; much lower than prevlousl_i repxtc:.
Ueasurements were obtained in seven adults who were fo have l,lmt ar sutarach:. <ii
anesthesia. They were flexed in the lateral position. We used d kl;i spinal iiecdle
connected by saline-filled rigid tuting ro a Gouid transducer. Pres: ures were rr:oz*aed
continuously on paper as the needle war smoothly advar.zed from ttw srin I:- fhi.
epidural space, and then into the sularachnoid space. rigur t 1 ihrw rlx- pws- .ire
drops obtained in each patient, and the sudden rise seen on er.ter ir,j t1.r su!,arar:.n_.d
space. Our measured EPs ranged from. -20 to -147 cs H?D. suggesting that pleu:~l
pressure is not a plausable explanation for the negative 1umSar EF. Tht tracing vfrci.
revealed repeated drops in pressure prior to dwal puncture; the possit,le TEZ. .: 1.5 fc,r
this will be discussed. Further sfudj. zf CP is suggesred and cou13 mzst easilv Ir
carried out in an active obstetrical unit.
Figure 1. Pressure Wacings in a?1
seven patients. Each Tracing starts , , f
0 cm HZO_ The effect of dural tenting
on the recorded pressurt is seer, most
clearly in the firsr tra:ing (arrow). -.
SUXAMETHONIUM APNOEIA: MANAGEMENT IMPLICATIONS
Sarah Varghese, M.D. , Assistant Professor - Obstetrical Anesthesia Johns Hopkins Hospital, Baltimore, Maryland
The clinical use of Suxamethonium, a short-acting depolarizing muscle relaxant is noted for its occassional associatin with prolonged apnoea in pregnancy. When this occurs a low activity of psuedocholinesterase (CHE) in the plasma due to a disease condition or a qualitative (genetic) abnormality is often attributed as the predominent cause. The CHE activity normally drops from the 10th week of pregnancy onwards and reaches its lowest level 2-3 days post portum.
Even though there is evidence in the literature to suggest that Suxamethonium apnoea is no longer a clinical problem, provided that a logical and scientific approach to the diagnosis and treatment is adopted, it still continues to be of clinical concern in the obstetric population. In patients undergoing general surgical procedures the duration of operation is normally longer and blood transfusions are administered more of ten then during Caesarean Sect ions. Accordingly the chances of detecting a prolonged effect of suxamethonium are minimized.
This presentation examines a case of prolonged Suxamethomium induced paralysis and suggests an approach to the safe management of this problem. A case is presented in which the administration of 1OOmg of Suxamethonium and 3.5mg of Pancuronium, followed by 5 mg of Prostigmine (to reverse the effect of the Pancuronfum) resulted in 6 hrs of apnoea in an otherwise healthy multiparous woman undergoing Caesarean Section. Subsequently her CHE activity was determin- ed to have been 0.2 units/ml (normal 3.0-8.0 units/ml) and qualitatively normal. in the immediate post-operative period. Six weeks post partum the patient’s CHE activity had returned to normal (3.4 u/ml). It is postulated that the prolonged apnoea was due to a physiologically reduced CHE activity and the superimposed ant icholines terase ef feet of Pros tigmine.
Discussion:
This case demonstrates the occurance of prolonged apnoea in the absence of systemic illness or genetic abnormality in women undergoing Caesarean Sections. This also emphasizes the value of restraining the addition a non-depolarising muscle relaxant during anesthesia for a Caesarean Section before the effects of the depolarising neuromuscular blocking agent have dissipated. Otherwise it is necessary to use a peripheral nerve stimulator to determine the quality of the neromuscular block before attempting to reverse it with a long-acting anti-CHE agent. Failure to do so could prolong a depolarising block due to suxamethonium. Suggested measures in the management of prolonged neuromuscular block are as follows: first, determine the nature of the block, second, if it is a persis- tent depolarisation block maintain mechanical ventilation until the respiratory mechanics are adequate, and determine qualitative and quantitative CHE activity; or if it is a non-dcpolarisntlon block or a phase II block, perform an Edropho- nium test, and if improvement results after Edrophonium, give a long-acting ant I-CHE agent. Maintaining adequate ventilation and patience are the most important therapeutic measures.
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Relationship of Fibrinogen Levels to Prolonged Rupture of Membranes and Sepsis
Donna-Jean B. Walker, M.D.; Chief Pediatric Resident - Paul F. 'Ikist, D.O.; Director of Neonatolow
Nassau Hospital 259 First Street Mineola, N.Y. 11501
. .
The presentsttiywas begun to ascertain if there is acorrelation betwen fibrinoqenlevels and prolonged ruptureofmsnbranes with evident of infection inthenuther and/or infant.
In our institution all babies admitted to the intensive care nursery receive a clotting screen. Previous studies have sti that nomml fibrino- gen levels in term infants is 215 * 35 and that of preterm infants slightly lm but with greater variability. During a twoweek period three babies admitted to theNBICU derronstrated fibrincgenlewls greater than 400. Aaxmondenminatorwas thatallthreehereprxkerminfants born to rr0tkr-S with prolcxged mptureofnwnbranes. fie mot&r and/or baby had evidence of infection.
The mntrol group consists of 40 preterm and 40 term infants born with- out prolonged rupture of membranes and without suspicion of infection. Fibrinogen levels ware drawn on these babies. The study group contains infants born 24 hours or n-ore after rwmbranes ruptured. Evidencr? of maternal infection includes fever,leukccytosis or positive cultures. Placentas were examined for chxicarfmionitis. The newborns were evaluated for clinical evidence of infection or positive cultures and fibrinogen levels were drawn for correlation.
91
THREE PERCENT 2-CHLOROPROCAINE FOR CESAREAN SECTION. APPRAISAL OF A STANDARDISED DOSE TECHNIQUE. W.D.R. Writer, M.B., Ch.B., D.M. Dewan, M.D., F.M. James, III, M.D. The Department of Anesthesia, Bowman Gray School of Medicine, Winston-Salem, N.C. 27103
Epidural anesthesia with 2-chloroprocaine produces greater maternal hypotension than bupivacaine, but offers rapid onset of analgesia in Cesarean section. We found sow patients to require more than 20 ml of 3 percent,used by James et al. A safe procedure must allow time to exclude accidental intrathecal or intravascular administration. We have evaluated a technique fulfilling these criteria, which uses a minimum of 25 ml.
METHODS: We studied 44 parturients having elective Cesarean section. The Clinical Research Practices Committee approved the protocol and all participants gave informed consent. After establishing a 16 gauge I.V. cannula, we recorded baseline pulse and blood pressure (Riva-Rocci method) and infused 1 liter of balanced salt solution. Lumbar epidural block was performed on recumbent subjects in the left lateral position and.an epi- dural cannula inserted. Mothers then received an 'intrathecal' test dose of 2 ml through the cannula. Five minutes later we asked them to move both legs and report any diffuse numbness. In the absence of change we administered chloroprocaine 8 ml, slowly, questioning about symptoms of intravascular injection. Parturients then assumed the left tilt position, wedged beneath the right hip. We continued rapid electrolyte infusion and recorded cardiovascular parameters every 2 min. giving T.V. ephedrine, 10 mg, for abrupt or sustained hypotension not responding to fluid or increased tilt. Ten minutes after the 'intravascular' test dose we noted the upper analgesia level, then gave a 'therapeutic' dose of chloroprocaine 15 ml. Ten minutes later we recorded anesthetic level, requiring numbness at T5 or above before surgery and gave 5 ml increment(s), if needed to achieve this. During surgery mothers received chloro- procaine 10 ml every 40 min. We graded analgesia with a pain relief score three times during surgery. Neonatal status was assessed by Apgar scores and cord blood gases. Recovery time of motor and sensory function was noted.
RESULTS: Thirty-seven subjects (84 percent) demonstrated excellent analgesia; 3 (7 percent) obtained good relief. Pain occurred most frequently between delivery and parietal closure. Four mothers required supplementary N20 analgesia. Twenty-seven parturients (61 percent) attained T5 with chloroprocaine 25 ml; eleven (25 percent) required 30 ml. Mothers over 35 years, or having a BMI (body mass index) >35, demonstrated higher segmental levels. Upward drift (3.8t1.7 segments) followed the therapeutic dose but not the later 10 ml doses. Motor (64t21 min.) and sensory (68'20 min.) function returned rapidly. Hypotension (MAP<80 percent control) occurred in 24 parturients. An infused volume >30 ml/kg at &livery significantly reduced post-delivery hypotension. Neonates from hypotensivc mothers demonstrated significantly lower HCO; values (P<.O5).
We shall discuss these findings.
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EFFECTS OF SPINAL ANESTHESIA ON MATERNAL ENDOGENOUS CATECHOLAMINES AND NEONATAL OUTCOME
Theresa Abboud MD, R. Artal MD, E. Henriksen MD, and S. Earl, CRNA
Department of Anesthesiology, Obstetrics and Gynecology - LAC-USC Medical Center
Drs. Shnider, Abboud and Artal have shown that lumbar epidural anesthesia during labor decreases maternal catecholamines(l). This study was under-t-aken to del ineate
if the mechanism of this reduction was denervation of the adrenal gland or relief of pain. Method : Twenty-three parturients undergoing cesarean section under splnal anesthesia were studied. The patients were divided into two groups (Group I) n=9 patients in labor, and (Group II) n=l4 patients not in labor, Spinal anesthesia was performed in the usual manner and was followed by left uterine displacement and administration of oxygen via a face mask. IOmg of ephedrine was glven Intravenously to treat any hypo- tens ion (BP< 100 or 3OjC). Maternal venous blood samples for catecholamine determi- nation were obtained prior to the block, during the abdominal preparation and at the time of delivery. Tidal volume was measured before and after the block using a spirometer. Incidence of nausea and vomltlng was noted. At the time of delivery maternal arterial (MA) and umbilical arterial (UA) and venous (UV) blood samples were obtained for acid base determination and Apgar scores were noted. Early Neonatal
Neurobehavioral Examination (ENNS) was performed at 2 and 24 hours of age. The data was normal Gaussian and Log distributed and analysed for significance by Wllcoxon matched-pairs signed-ranks test and Student’s t-test.
Results and Conclusions: Spinal anesthesia Is followed by a significant reduction
‘in circulating plasma norepinephrine (NE) In patlents in labor. No reduction was
found In patients not ln labor desplte J4 or higher sensory levels. These findings are consistent with those previously reported of no change in circulating catecho- lamines after epldural anesthesia in patients not In labor(*). There is no uniform epinephrlne (E) response in either group indicating that In spite of sympathetic blockade in stressful conditions there is an additional source of eplnephrine. Epine-
phrine could orlginate from the metabolized circulating norepinephrine. No signifi- cant changes in catecholamine concentrations have been observed after administration of ephedrlne. Results are summarized in table:
-- Del lvery
800+500 5952230
GROUP I (LABOR)
Prep- -
1083**+480 326+ I 02 0 (01 4 (44) 7.43tO.24
24+0.5 511257 7.1820.05 6-fl 2 (22)
7-
NE(pG/ml’SEM) E (pG/mI?SEM) Hypotenslon ($1 Emesis ($1 MA-pH MA-PC02 EBL UA-pH UA-BD Acidemia
(pH UA <7.20, VA<7.25)
Apgar Scores <7 at l/5 min.
+ p<o.o5 t*
Base1 ine
2000*630
34 I‘132
1 o/o
GROUP I I (NO LABQRI
Base1 Ine
17852347 3752105
Prep
1907+273 357+85 7 (50)” II (78) 7.442.01 24.6+1 519+41 7.232.02 6fl 2 (14)
O/O
Dellvery
2204:362
405+58
References:
I. Shnlder SM, Abboud T, Artal R, et al: Maternal Endogenous Catecholamines decrease during labor after lumbar epldural anesthesia. Anesthesiology 53:299, 1980
2. Richard GW, Shnider SM, Levinson G, et al: Maternal and Fetal Plasma Norepinephrine
Levels During Epidural Anesthesia for Elective Cesarean Section. ASA Book of Ab-
stt”aCt: PCI. 110. 1978 ^^