Analgesia for Labor and DeliveryAnalgesia for Labor and Delivery

ALWAYSALWAYS controversial ! controversial !

““Birth is a natural process”Birth is a natural process”

Women should suffer!!Women should suffer!!

Concerns for mother’s safetyConcerns for mother’s safety

Concerns for babyConcerns for baby

Concerns for effects on labor Concerns for effects on labor

HistoryHistory Garden of EdenGarden of Eden

Original SinOriginal Sin

God punished Eve: “In sorrow thou shalt bring forth children.” God punished Eve: “In sorrow thou shalt bring forth children.” Genesis 3:16Genesis 3:16

Formed the basis of Formed the basis of 1800 years of opposition1800 years of opposition to pain relief in labor.to pain relief in labor.

15911591

Lady Euframe MacAlyane of Edinburgh, Scotland: Lady Euframe MacAlyane of Edinburgh, Scotland: was Burned was Burned

at the Stake because asking for labor analgesia.at the Stake because asking for labor analgesia.

HISTORYHISTORY 1847 – James Young Simpson; ETHER1847 – James Young Simpson; ETHER 1853 – John Snow ; CHLOROFORM1853 – John Snow ; CHLOROFORM

- Queen Victoria, 8- Queen Victoria, 8th th childchild

“ “The inhalation lasted fifty-three The inhalation lasted fifty-three

minutes. The chloroform was given . The chloroform was given

on a handkerchief in fifteen minim on a handkerchief in fifteen minim

doses; the Queen expressed herself doses; the Queen expressed herself

as greatly relieved by the as greatly relieved by the

administration.”administration.”

Chloroform a’ la reineChloroform a’ la reine

Chloroform a’ la reineChloroform a’ la reine

“Dr Snow gave me the blessed

chloroform and the effect was soothing,

quieting and delightful beyond measure”

History contd..History contd..

1855 1855

Religious acceptanceReligious acceptance Archbishop of Canterbury's (leader ofArchbishop of Canterbury's (leader of the Anglican/Episcopal Church) daughter received the Anglican/Episcopal Church) daughter received

chloroform for labor pains. He refused to criticize.chloroform for labor pains. He refused to criticize.

1860-1940 : Dark ages of obstetric anesthesia1860-1940 : Dark ages of obstetric anesthesia

HistoryHistory

August Bier ,…………….., August Bier ,……………..,

Virginia Apgar ,…Virginia Apgar ,…

1900 1900 ::

Oskar Kreis Oskar Kreis , used spinal anesthesia for , used spinal anesthesia for childbirth for the first timechildbirth for the first time

1933 : John Cleland – pain pathways1933 : John Cleland – pain pathways

1943 : Hingson – Continuous caudal1943 : Hingson – Continuous caudal

1949 : Flowers - Continuous lumbar epid.1949 : Flowers - Continuous lumbar epid.

DEFINITION OF PAINDEFINITION OF PAIN

ISAP - ISAP - AS AN UNPLEASANT SENSORY AS AN UNPLEASANT SENSORY AND EMOTINAL EXPERIENCE AND EMOTINAL EXPERIENCE ASSOCIATED WITH ACTUAL ASSOCIATED WITH ACTUAL POTENTIAL TISSUE DAMAGE (OR) POTENTIAL TISSUE DAMAGE (OR) DESCRIBED IN TERMS OF SUCH DESCRIBED IN TERMS OF SUCH DAMAGE.DAMAGE.

TERMINOLOGYTERMINOLOGY

NOCICEPTIONNOCICEPTION:DETECTION,TRANSDUCTION,AND:DETECTION,TRANSDUCTION,AND

TRANSMISSION OF NOXIOUS STIMULITRANSMISSION OF NOXIOUS STIMULI

NOCICEPTORSNOCICEPTORS:FREE NERVE ENDINGS ACTIVATED:FREE NERVE ENDINGS ACTIVATED

BY NOXIOUS STIMULI.BY NOXIOUS STIMULI.

PHYSIOLOGIC PAINPHYSIOLOGIC PAIN:NOXIOUS STIMULI ACTIVATING:NOXIOUS STIMULI ACTIVATING

||

NOCICEPTORS ACCOMPANIED BY WITHDRAWALNOCICEPTORS ACCOMPANIED BY WITHDRAWAL

PATHOLOGIC PAINPATHOLOGIC PAIN: NON NOXIOUS STIMULI PRODUCING PAIN: NON NOXIOUS STIMULI PRODUCING PAIN

PHYSIOLOGY OF PAINPHYSIOLOGY OF PAIN

PATHWAYSPATHWAYS

MEDIATORSMEDIATORS

PERCEPTIONPERCEPTION

PATHWAYSPATHWAYS

PERIPHERAL AFFERENT(FIRSTORDER NEURON)PERIPHERAL AFFERENT(FIRSTORDER NEURON)

||

DORSAL ROOT GANGLIONDORSAL ROOT GANGLION

||

DORSAL HORN(SECOND ORDER)DORSAL HORN(SECOND ORDER)

||

CONTRALATERAL HEMISPHERECONTRALATERAL HEMISPHERE

||

SPINOTHALAMIC TRACTSPINOTHALAMIC TRACT

||

THALAMUS THALAMUS

MECHANISMS MECHANISMS

PERIPHERALPERIPHERAL

CENTRALCENTRAL

PERIPHERAL MECHANISMSPERIPHERAL MECHANISMS

NOCICEPTORS:NOCICEPTORS: 1.NON MYELINATED(c-fibers) 1.NON MYELINATED(c-fibers)

2.MYELINATED(A-DELTA)2.MYELINATED(A-DELTA) POLYMODAL.POLYMODAL. A-DELTA- SHARP,HEAT,PRESSUREA-DELTA- SHARP,HEAT,PRESSURE C-FIBERS-DULL BURNING PAIN.C-FIBERS-DULL BURNING PAIN. PATHOLOGICAL PAIN-A-BETA.PATHOLOGICAL PAIN-A-BETA.

CHEMICAL MEDIATORSCHEMICAL MEDIATORS

BRADYKININBRADYKININ HISTAMINEHISTAMINE EICOSANOIDSEICOSANOIDS SUBSTANCE-PSUBSTANCE-P 5-HT5-HT ATPATP H2 IONH2 ION OPIOID PEPTIDESOPIOID PEPTIDES

CENTRAL MECHANISMSCENTRAL MECHANISMS

NOCICEPTIVE AFFERENTS DORSAL ROOT NOCICEPTIVE AFFERENTS DORSAL ROOT GANGLION DORSALHORNGANGLION DORSALHORN

C&SOME A-DELTA SUPERFICIAL LAMINA(1&2)C&SOME A-DELTA SUPERFICIAL LAMINA(1&2)SOME A-FIBERS —LAMINA - 5SOME A-FIBERS —LAMINA - 530% -C-FIBERS —DOUBLE BACK THROUGH30% -C-FIBERS —DOUBLE BACK THROUGH VENTRAL ROOTVENTRAL ROOT1&5 -------THALAMUS1&5 -------THALAMUSLAMINA 2—SUBSTANTIA GELATINOSA (INHIBITORY)LAMINA 2—SUBSTANTIA GELATINOSA (INHIBITORY)

““THE GATE CONTROL THEORY OF PAIN”THE GATE CONTROL THEORY OF PAIN”

MODULATORS AT SPINALMODULATORS AT SPINAL CORD CORD

OPIOID PEPTIDESOPIOID PEPTIDES

BIOGENIC AMINESBIOGENIC AMINES

OTHERSOTHERS

SUPRASPINAL MODULATIONSUPRASPINAL MODULATION

PERIAQUEDUCTAL GREY(PAG) MATTERPERIAQUEDUCTAL GREY(PAG) MATTER DESCENDING INHIBITORY PATHDESCENDING INHIBITORY PATH LOSS OF RESPONSE TO NOXIOUS STIMULILOSS OF RESPONSE TO NOXIOUS STIMULI RESPONSE TO STIMULI-3 WAYSRESPONSE TO STIMULI-3 WAYS

““ON CELLS” FACILITATE NOCICEPTIVE ON CELLS” FACILITATE NOCICEPTIVE TRANSMISSIONTRANSMISSION

““OFF CELLS” INHIBITS TRANSMISSIONOFF CELLS” INHIBITS TRANSMISSION ““NEUTRAL CELLS”NO CHANGE IN FIRINGNEUTRAL CELLS”NO CHANGE IN FIRING

Grading Of PainsGrading Of Pains

PAIN PATHWAYSPAIN PATHWAYS

1st stage of labor – mostly visceral1st stage of labor – mostly visceral Dilation of the cervix and distention of the

lower uterine segment Dull, aching and poorly localized Slow conducting, C fibers, T10 to L1

2nd stage of labor – mostly somatic2nd stage of labor – mostly somatic Distention of the Distention of the pelvic floor, vagina and pelvic floor, vagina and

perineumperineum Sharp, severe and well localizedSharp, severe and well localized Rapidly conducting, A-delta fibers,S2 to S4Rapidly conducting, A-delta fibers,S2 to S4

Labor Pain & Stages of Labor

Eltzschig, Leiberman, Camann, NEJM 348; 319:2003Eltzschig, Leiberman, Camann, NEJM 348; 319:2003

Effects of labor painEffects of labor pain

Maternal hyperventillationMaternal hyperventillationHypocarbia – Uteroplacental vasoconstrictionHypocarbia – Uteroplacental vasoconstriction

- ODC to left- ODC to left↑↑O2 consumptionO2 consumption ↑↑Cardiac output, ↑BPCardiac output, ↑BP ↑ ↑Maternal plasma catecholaminesMaternal plasma catecholamines

Fetal acidosis and hypoxiaFetal acidosis and hypoxia

Ill effects Of Pain?Ill effects Of Pain?

High risk parturient – Pre-eclampsiaHigh risk parturient – Pre-eclampsia

- Cardiac disease- Cardiac disease

- Asthma- Asthma

Marginal uteroplacental circulationMarginal uteroplacental circulation

Prolonged laborProlonged labor

Labor Analgesia

Non-Pharmacological Pharmacological

Non-PharmacologicalNon-Pharmacological

Psycho prophylaxis – Lamaze, DoulaPsycho prophylaxis – Lamaze, DoulaTENSTENSAcupunctureAcupunctureHydrotherapyHydrotherapy Intradermal water inj.Intradermal water inj.

ACUPUNTUREACUPUNTURE

Generally two local points and two distal points on the Generally two local points and two distal points on the arms or on the legs are selected.arms or on the legs are selected.

Begin Acupuncture 4 weeks before the expected time ofBegin Acupuncture 4 weeks before the expected time of delivery.delivery. Needles are placed once a week using the specific points.Needles are placed once a week using the specific points.

PointsPoints LI.4 Hegu, SP.6 Saninjiao, Extra NeimaLI.4 Hegu, SP.6 Saninjiao, Extra NeimaPC 6 (Neiguan), Du.20,Du.2,Du6, GB.21,PC 6 (Neiguan), Du.20,Du.2,Du6, GB.21,He.7(shenmen)He.7(shenmen)

TENSTENS

Beneficial in patients with moderate to severe Beneficial in patients with moderate to severe contraction pains in an otherwise reasonably contraction pains in an otherwise reasonably

normal labor.normal labor. Very popular in Europe.Very popular in Europe. Easy to apply, non-toxic and frequently Easy to apply, non-toxic and frequently

effective.effective. 4 electrodes are placed one on either side of 4 electrodes are placed one on either side of

the the spine in the lower thoracic region (T 10) and spine in the lower thoracic region (T 10) and

one one on either side of the spine in the sacral area.on either side of the spine in the sacral area. The patient may control up to 3 levels of The patient may control up to 3 levels of

intensityintensity of stimuli, and she can switch it off if she of stimuli, and she can switch it off if she

wishes.wishes.

Pharmacological

Systemic Medications

Inhalational Regional Blocks

Factors Determining Fetal Drug LevelsFactors Determining Fetal Drug Levels Lipid solubilityLipid solubility

Molecular size Molecular size

Total dose of drugTotal dose of drug

Concentration gradientConcentration gradient

Maternal metabolism and excretionMaternal metabolism and excretion

Degree of ionizationDegree of ionization

pKa of drug, maternal and fetal pHpKa of drug, maternal and fetal pH

Protein binding - mother and fetusProtein binding - mother and fetus

Uterine blood flowUterine blood flow

Time for equilibrium to occurTime for equilibrium to occur

Systemic Opioids in LaborSystemic Opioids in Labor

Easy administrationEasy administration

InexpensiveInexpensive

No needlesNo needles

Avoids complications of regional blockAvoids complications of regional block

Does not require skilled personnelDoes not require skilled personnel

Few serious maternal complicationsFew serious maternal complications

Perceived as “natural”Perceived as “natural”

Advantages:Advantages:

Systemic Opioids - DisadvantagesSystemic Opioids - Disadvantages

Placental transferPlacental transfer

Inadequate pain reliefInadequate pain relief

Maternal sedationMaternal sedation

Nausea, vomiting, gastric stasisNausea, vomiting, gastric stasis

Fetal heart rate effects:Fetal heart rate effects:

Loss of beat-to-beat variabilityLoss of beat-to-beat variability

Sinusoidal rhythmSinusoidal rhythm

Dose-related maternal / neonatal depressionDose-related maternal / neonatal depression

Newborn neurobehavioral depressionNewborn neurobehavioral depression

Potential Fetal/Neonatal Effects Potential Fetal/Neonatal Effects

Low 1 and 5 min Apgar scoresLow 1 and 5 min Apgar scores

Respiratory acidosisRespiratory acidosis

Naloxone/ ventilatory assistance may be neededNaloxone/ ventilatory assistance may be needed

Neurobehavioral depression - dose dependentNeurobehavioral depression - dose dependent

Occasionally, prolonged observation in NICU neededOccasionally, prolonged observation in NICU needed

MepridineMepridine: 50-100mg IM / 25-50mgIV: 50-100mg IM / 25-50mgIV

onset: 45mins / 5minsonset: 45mins / 5mins

neonatal depr: 3hrs / 20 minsneonatal depr: 3hrs / 20 mins

optimal time: >4hrs / <1hroptimal time: >4hrs / <1hr

FentanylFentanyl: 50-100: 50-100µg/hr, µg/hr, peaks @ 3-5minspeaks @ 3-5mins

RemifentanilRemifentanil : : ½life 6mins, 0.5mirogms/kg½life 6mins, 0.5mirogms/kg

Butraphanol, Nalbhuphine, PhenothiazinesButraphanol, Nalbhuphine, Phenothiazines

IV-PCA Fentanyl during Labor IV-PCA Fentanyl during Labor

Loading dose -50-100Loading dose -50-100µµgg

No background infusionNo background infusion

10-12.510-12.5µµg bolusg bolus

8-10 min lockout8-10 min lockout

4 hour limit - 300 mcg4 hour limit - 300 mcg

Pulse oximeter when large doses Pulse oximeter when large doses

Inhalation Analgesia Inhalation Analgesia

Advantages:Advantages:

Easy to administer (no needles Easy to administer (no needles

or PDPH)or PDPH)

“ “Satisfactory” analgesia variableSatisfactory” analgesia variable

Minimal neonatal depressionMinimal neonatal depression

Entonox (N2O:O2 = 50:50), %,

Inhalational AnalgesiaInhalational Analgesia

Isoflurane ( 0/2%)Isoflurane ( 0/2%) Enflurane (0/2%)Enflurane (0/2%) Desflurane (0/2%)Desflurane (0/2%)

LIMITED USELIMITED USE

Drowsiness ,Unpleasant smell, High cost,Drowsiness ,Unpleasant smell, High cost,

Accidental overdoseAccidental overdose

Inhalation Analgesia Inhalation Analgesia

Disadvantages:Disadvantages:

Decreased uterine contractility (except NDecreased uterine contractility (except N22O)O)

Rapid induction of anesthesia in pregnancyRapid induction of anesthesia in pregnancy

Risk of unconsciousness and aspirationRisk of unconsciousness and aspiration

Difficulties with scavenging in labor roomsDifficulties with scavenging in labor rooms

Regional blocksRegional blocks

Paracervical BlockParacervical Block

Local bilateral injection near the cervixLocal bilateral injection near the cervix Given during 1Given during 1stst stage of labor stage of labor Lasts about 2 hoursLasts about 2 hours

DisadvantageDisadvantage fetal bradycardiafetal bradycardia Lidocaine toxicityLidocaine toxicity

Pudendal BlockPudendal Block

Perineal anaesthesiaPerineal anaesthesia Second stage of laborSecond stage of labor

Most effective & Least depressantMost effective & Least depressant Great versatility – Extent & DurationGreat versatility – Extent & Duration Reduces maternal CatecholsReduces maternal Catechols ↑↑Intervillous blood flowIntervillous blood flow

Improved Uteroplacental perfusionImproved Uteroplacental perfusion Low dose LA – Low dose LA – NO Effect on Uterine activityNO Effect on Uterine activity Low dose opioids – Low dose opioids – NO neonatal depressionNO neonatal depression

Neuraxial Blocks - advantagesNeuraxial Blocks - advantages

Regional Analgesia - Neonatal Effects Regional Analgesia - Neonatal Effects

Uterine perfusion maintained Uterine perfusion maintained

FHR changes:FHR changes:

baseline variabilitybaseline variability

periodic decelerations (due toperiodic decelerations (due to maternal catechols?) maternal catechols?)

Apgar scores, acid-base status - unaffectedApgar scores, acid-base status - unaffected

Neurobehavioral effects absentNeurobehavioral effects absent

LA toxicity - LA toxicity - extremelyextremely rare rare

Profound hypotension - possible fetal compromiseProfound hypotension - possible fetal compromise

IndicationsIndications

PAIN EXPERIENCED BY A WOMAN IN LABORPAIN EXPERIENCED BY A WOMAN IN LABOR

ACOG and ASA statedACOG and ASA stated

“ “ in the absence of a medical contraindication, maternal in the absence of a medical contraindication, maternal request is a sufficient medical indication for pain request is a sufficient medical indication for pain relief…”relief…”

Points of controversyPoints of controversy When?When? Who?Who? How?How?

Particularly beneficialParticularly beneficial

Hypertensive disordersHypertensive disorders Cardiac diseaseCardiac disease AsthmaAsthma Diabetes Diabetes Prolonged lobor/ Oxytocin augmentationProlonged lobor/ Oxytocin augmentation PrematurityPrematurity Multiple gestationMultiple gestation Vaginal breech deliveryVaginal breech delivery

Blunts Haemodynamic response

Depressant effects of opioids avoided

Am J Obstet Gynecol 1983;147:13-5.

Maternal catecholamines decrease during labor Maternal catecholamines decrease during labor after lumbar epidural analgesia. after lumbar epidural analgesia.

ContraindicationsContraindications

ABSOLUTEABSOLUTE Patients refusal Patients refusal Inability to cooperateInability to cooperate Increased intracranial Increased intracranial

pressure pressure Infection at the site Infection at the site Frank coagulopathyFrank coagulopathy Hypovolemic shockHypovolemic shock

RELATIVERELATIVE Systemic maternal infectionSystemic maternal infection Preexisting neurological Preexisting neurological

deficiencydeficiency Mild coagulation Mild coagulation

abnormalitiesabnormalities Relative hypovolemiaRelative hypovolemia Poor communicationPoor communication

GOALS OF LABOR ANALGESIAGOALS OF LABOR ANALGESIA

Dramatically reduce pain of laborDramatically reduce pain of labor Should allow parturients to participate in birthing Should allow parturients to participate in birthing

experienceexperience Minimal motor block to allow ambulationMinimal motor block to allow ambulation Minimal effects on fetusMinimal effects on fetus Minimal effects on progress of laborMinimal effects on progress of labor

How to Achieve Goals:How to Achieve Goals:What you put in:What you put in:

Drugs, concentrations, combinationsDrugs, concentrations, combinations

How you deliver it:How you deliver it:

Intermittent boluses, Continuous, PCEAIntermittent boluses, Continuous, PCEA

How much you give:How much you give:

Low Vs. High infusion ratesLow Vs. High infusion rates

Neuraxial BlocksNeuraxial Blocks

Epidural aloneEpidural alone Combined epidural and spinalCombined epidural and spinal Spinal aloneSpinal alone

Local anaesthetics(LA) aloneLocal anaesthetics(LA) alone Opioids and LAOpioids and LA Opioids aloneOpioids alone

Spinal opioids alone: very high risk ptsSpinal opioids alone: very high risk pts Epidural opioids alone: High dosesEpidural opioids alone: High doses Spinal LA alone: Saddle block, 6mg bupivacaineSpinal LA alone: Saddle block, 6mg bupivacaine

Epidural LA aloneEpidural LA alone Epidural LA + Opioid Epidural LA + Opioid ± Adjuvants± Adjuvants Combined Spinal & epidural – LA+Opioid Combined Spinal & epidural – LA+Opioid

± Adjuvants± Adjuvants Continuous spinal – LA ± OpioidsContinuous spinal – LA ± Opioids

Neuraxial BlocksNeuraxial Blocks

Choice Of Local AnestheticChoice Of Local Anesthetic

Rapid onset with minimal motor blockRapid onset with minimal motor block Minimal risk of maternal toxicityMinimal risk of maternal toxicity Negligible effects on uterine activity and Negligible effects on uterine activity and

uteroplacental perfusionuteroplacental perfusion Limited uteroplacental transferLimited uteroplacental transfer Long duration of actionLong duration of action

Choice of Epidural LAChoice of Epidural LA

Lignocaine:Lignocaine: Rapid onset, Dense motor block, Risk of Rapid onset, Dense motor block, Risk of cummulative toxicity, UV/MV ratio – 0.6 cummulative toxicity, UV/MV ratio – 0.6

Chlorprocaine:Chlorprocaine:Rapid onset, Low toxicity, Dense block, Rapid onset, Low toxicity, Dense block, Antagonises bupivacaine &poioidsAntagonises bupivacaine &poioids

Bupivacaine( 0.0625%):Bupivacaine( 0.0625%): Good sensory, Minimal motorGood sensory, Minimal motor block, 2hrs, No adverse effects onblock, 2hrs, No adverse effects on labor, UV/MV – 0.3labor, UV/MV – 0.3

Ropivacaine:Ropivacaine: Lower toxicity, ?Less motor block, Less Lower toxicity, ?Less motor block, Less potentpotent

Levobupivacaine:Levobupivacaine: Lower toxicityLower toxicity

Epinephrine Use in LaborEpinephrine Use in Labor May transiently slow laborMay transiently slow labor

Increases motor block, Improves analgesiaIncreases motor block, Improves analgesia

Epinephrine test dose Epinephrine test dose often avoidedoften avoided in labor in labor

Low specificity - maternal heart rate very variable Low specificity - maternal heart rate very variable

Low sensitivity - Low sensitivity - response to sympathomimetics response to sympathomimetics

Increases motor block - prevents ambulationIncreases motor block - prevents ambulation

Potential for Potential for UBF with repeated doses UBF with repeated doses

VeryVery dilute agents - “whole first dose is test dose.” dilute agents - “whole first dose is test dose.”

Epidural Opioids in LaborEpidural Opioids in Labor

Inadequate analgesics if used alone Inadequate analgesics if used alone

Synergize with local anestheticsSynergize with local anesthetics

Speed onset of analgesiaSpeed onset of analgesia

Improve quality of analgesiaImprove quality of analgesia

Permit use of very dilute LA solutionsPermit use of very dilute LA solutions

Help relieve persistent perineal pain and Help relieve persistent perineal pain and

unblocked segmentsunblocked segments

Effect of low conc LA + opioid Effect of low conc LA + opioid

0

10

20

30

40

50

"Traditional" Low-doseInfusion

Spontaneous

Instrumental

C/Section

% % PatientsPatients

****

(Comet Study UK , Lancet 2001;358:19)(Comet Study UK , Lancet 2001;358:19)

BupivacaineBupivacaine 0.25%0.25%

BupivacaineBupivacaine0.1% + fentanyl0.1% + fentanyl

Bupiv 2.5 mgBupiv 2.5 mg+ Fent 25 mcg+ Fent 25 mcg

**

Which Epidural Opioid ?Which Epidural Opioid ?

Fentanyl and SufentanilFentanyl and Sufentanil

Rapid onset, few side effectsRapid onset, few side effects

Sufentanil slightly more effectiveSufentanil slightly more effective

No significant fetal drug accumulationNo significant fetal drug accumulation

No serious adverse neonatal effectsNo serious adverse neonatal effects

Light or “Ultra-light Analgesic Light or “Ultra-light Analgesic Techniques Techniques

BupivacaineBupivacaine

Ropivacaine Ropivacaine + + OPIOIDOPIOID LevobupivacaineLevobupivacaine

Epidural analgesiaEpidural analgesia

Opioid: Fentanyl 1-2 Opioid: Fentanyl 1-2 µg/ml, µg/ml, Sufentanyl 0.2- Sufentanyl 0.2-0.5µg/ml0.5µg/ml

Continuous infusionContinuous infusion Bupivacaine 0.0625%-0.25%,8 -15 ml/hrBupivacaine 0.0625%-0.25%,8 -15 ml/hr Ropivacaine: 0.125%-0.25%, 6 -12 ml/hrRopivacaine: 0.125%-0.25%, 6 -12 ml/hr

Intermittent bolus injectionsIntermittent bolus injections Bupivacaine: 0.125%-0.375%, 5-10 ml, Bupivacaine: 0.125%-0.375%, 5-10 ml,

duration:1-2 hrduration:1-2 hr

Continous EpiduralContinous Epidural

Continuous epidural infusionContinuous epidural infusion““A larger volume of a more dilute agent is more A larger volume of a more dilute agent is more

effective for labor analgesia than a smaller effective for labor analgesia than a smaller volume of higher concentration”volume of higher concentration”

Good pain releifGood pain releifLess motor blockLess motor block Increased maternal hamodynamic stabilityIncreased maternal hamodynamic stabilitySafe drug concentrationsSafe drug concentrationsNo change in neonatal outcomeNo change in neonatal outcome

Good analgesiaGood analgesia Patient autonomyPatient autonomy Less anaesthetist interventions Less anaesthetist interventions Cost effectiveCost effective Lower total doseLower total doseBupivacaine 0.125% + Fentanyl 2Bupivacaine 0.125% + Fentanyl 2µg/ml – 6ml basal µg/ml – 6ml basal

infusion, 3ml bolus, 10min lockout interval, max infusion, 3ml bolus, 10min lockout interval, max 24ml/hr24ml/hr

PCEAPCEA

From Gambling DR et al. Comparison of patient-controlled epidural From Gambling DR et al. Comparison of patient-controlled epidural analgesia and conventional intermittent top up injections during labor. analgesia and conventional intermittent top up injections during labor.

Anesth Analg 1990;70:256-61Anesth Analg 1990;70:256-61..

Combined spinal-epiduralCombined spinal-epidural

Faster onset - intense analgesiaFaster onset - intense analgesia Additional flexibility - epiduralAdditional flexibility - epidural

Very low failure rateVery low failure rate

Minimal motor block if only opioid used for spinalMinimal motor block if only opioid used for spinal

Less need for supplemental bolusesLess need for supplemental boluses IT opioids: Fentanyl 5-25 IT opioids: Fentanyl 5-25 μμg, sufentanil 5-10 g, sufentanil 5-10 μμggEarly labor : opioid ± 0.125 mg bupivacaine; Early labor : opioid ± 0.125 mg bupivacaine;

Advanced labor: opioid ± 2-2.5 mg bupivacaineAdvanced labor: opioid ± 2-2.5 mg bupivacaine

COMBINED SPINAL EPIDURALCOMBINED SPINAL EPIDURAL

Needle” through “Needle” “ Back “ eye”Needle” through “Needle” “ Back “ eye”

Needle” through “Needle” technique is the bestNeedle” through “Needle” technique is the best Can be placed in lateral or sitting positionCan be placed in lateral or sitting position Walking Epidural possibleWalking Epidural possible

Onset of Analgesia: CSE vs. Onset of Analgesia: CSE vs.

Epidural Epidural Collis et al. Lancet 1995;345:1413Collis et al. Lancet 1995;345:1413

0

25

50

75

100

Baseline 5 10 15 20

Time (minutes)

CSE

Epidural

VAPS (0-100)

Combined spinal-epiduralCombined spinal-epidural

Not recommended - morbidly obese, difficult airway Not recommended - morbidly obese, difficult airway or non-reassuring fetal heart rateor non-reassuring fetal heart rate

Two interspace techniquesTwo interspace techniques Needle through needleNeedle through needle

--PDPH: 1% or less, small bore atraumatic needles.PDPH: 1% or less, small bore atraumatic needles.

-Subarchanoid migration of epidural catheter - No added -Subarchanoid migration of epidural catheter - No added risk with CSErisk with CSE

28 or 32-G catheters for 22 or 26-G spinal needles28 or 32-G catheters for 22 or 26-G spinal needles Bupivacaine 2.5mg+25Bupivacaine 2.5mg+25µg fentanyl, µg fentanyl,

1-2ml/hr of bupivacaine 0.125% + 2µg/ml fentanyl 1-2ml/hr of bupivacaine 0.125% + 2µg/ml fentanyl Cauda Equina Syndrome Cauda Equina Syndrome Restricted by FDA in 1992Restricted by FDA in 1992 Ongoing multi-institutional study – 28-G catheters Ongoing multi-institutional study – 28-G catheters

sufentanil ± bupivacainesufentanil ± bupivacaine Appears safeAppears safe

Continuous Spinal AnalgesiaContinuous Spinal Analgesia

Side effects of IT opioidsSide effects of IT opioids Nausea, VomittingNausea, Vomitting PruritisPruritis SedationSedation At very high doses - Resp depressionAt very high doses - Resp depression

- Fetal bradycardia- Fetal bradycardia Stratergy to ↓ side effect - Add LAStratergy to ↓ side effect - Add LA

- Lowest dose opioid- Lowest dose opioid

We are All Ready…Now What? We are All Ready…Now What?

Obstetrician is consulted Obstetrician is consulted Pre-anesthetic evaluation Pre-anesthetic evaluation Pt’s informed consentPt’s informed consent Fetal well-being assessed and reassured Fetal well-being assessed and reassured

(obstetrician?, midwife?, yourself?)(obstetrician?, midwife?, yourself?) Stage of labor/ Cervical dilatationStage of labor/ Cervical dilatation Resuscitation equipment and drugs are Resuscitation equipment and drugs are

immediately availableimmediately available Aspiration prophylaxisAspiration prophylaxis

Conduct of Labour analgesiaConduct of Labour analgesia

Baseline BP, HR, FHR Baseline BP, HR, FHR IV access, Preload 500 -1000mlIV access, Preload 500 -1000ml Perform epidural / CSEPerform epidural / CSE Pregnancy – Physiologic changesPregnancy – Physiologic changes Left lateral / sitting Left lateral / sitting R/O intrathecal/ IV placementR/O intrathecal/ IV placement 3-5cm catheter inside space3-5cm catheter inside space 4ml of the drug4ml of the drug

Monitoring:Monitoring: BP every 1 to 2 min , 20 minBP every 1 to 2 min , 20 min Continuous maternal HR during induction Continuous maternal HR during induction

(pulseoximetry)(pulseoximetry) Continuous FHR monitoringContinuous FHR monitoring Continual verbal communicationContinual verbal communication

After 5mins, 4-8ml of drug » T10-L1 blockAfter 5mins, 4-8ml of drug » T10-L1 block Alternatively continuous infusion /PCEAAlternatively continuous infusion /PCEA Assess progression of laborAssess progression of labor Treat every bolus as test doseTreat every bolus as test dose

Conduct of Labour analgesiaConduct of Labour analgesia

Nursed in lateral positionNursed in lateral position Second stage of labor – S2 -4Second stage of labor – S2 -4 Head end elevation, 4-8ml drug bolusHead end elevation, 4-8ml drug bolus Intermittent techniques – 10-15ml drugIntermittent techniques – 10-15ml drug Prolonged for instrumental delivery / Prolonged for instrumental delivery /

C.sectionC.section

Conduct of Labor analgesiaConduct of Labor analgesia

Inadequate analgesia

Inadequate doseInadequate dose Patency of catheterPatency of catheter Subdural placementSubdural placement Second stage of laborSecond stage of labor Catheter migrationCatheter migration Uterine ruptureUterine rupture

ComplicationsComplications

Hypotension: Hypotension: preloading, LUD, O2, fluid, ephedrinepreloading, LUD, O2, fluid, ephedrine

Inadequate analgesia:Inadequate analgesia:Unintentional intravascular placement: Unintentional intravascular placement:

slow injection of dilute conc – less risk slow injection of dilute conc – less risk ligonocaine – light headedness, perioral numbness, seizures. ligonocaine – light headedness, perioral numbness, seizures. Bupivacaine – Ventricular arrythmia, cardiac arrestBupivacaine – Ventricular arrythmia, cardiac arrest

Unintentional intrathecal placement: Unintentional intrathecal placement: Hypotension, total spinal, PDPHHypotension, total spinal, PDPH

Subdural placement :Subdural placement :patchy block, high levelpatchy block, high level

Fetal Heart Rate

Management of FHR ChangesManagement of FHR Changes

Left uterine displacementLeft uterine displacement

Maternal position changeMaternal position change

OO22 administration administration

STOP OXYTOCIN! STOP OXYTOCIN!

Fetal scalp stimulationFetal scalp stimulation

Nitroglycerin: 400 µg sublingual X 2 (or more)Nitroglycerin: 400 µg sublingual X 2 (or more)

Terbutaline 0.25 mg, subcutaneousTerbutaline 0.25 mg, subcutaneous

Treat hypotensionTreat hypotension

Ephedrine - Ephedrine - epinephrine level; epinephrine level; UBF UBF

Controversial areas

Maternal pyrexia: ↑0.1 C/hr, No infection, No neonatal sepsis

Progress of Labor: ?only minimally prolongs

Rate of C/S: Not increased

Epidural test dose: ? Adrenaline, ?isoprotenerol Careful aspiration

Avoiding Epidural Disasters Avoiding Epidural Disasters

Maintain constant verbal contactMaintain constant verbal contact Always aspirate before each injectionAlways aspirate before each injection Observe for passive return through the catheterObserve for passive return through the catheter Do not inject more than 4 ml of LA at a timeDo not inject more than 4 ml of LA at a time Observe the patient at least 1.5-2 min between bolusesObserve the patient at least 1.5-2 min between boluses If in doubts, repeat test dose. Still in doubts? Replace itIf in doubts, repeat test dose. Still in doubts? Replace it After all, be mentally prepare to treatAfter all, be mentally prepare to treat

1.1. ConvulsionsConvulsions

2.2. Total spinalTotal spinal

3.3. Cardiovascular collapse and arrestCardiovascular collapse and arrest

ConclusionsConclusions

Individualize technique to patient’s goals and Individualize technique to patient’s goals and

stage of laborstage of labor

Optimize management for spontaneous deliveryOptimize management for spontaneous delivery

Provide safe, cost-effective analgesiaProvide safe, cost-effective analgesia

The Ideal Labor AnalgesicThe Ideal Labor Analgesic Good pain reliefGood pain relief

No autonomic block (no hypotension)No autonomic block (no hypotension)

No adverse maternal or neonatal effectsNo adverse maternal or neonatal effects

No motor blockNo motor block

No effect on labor and delivery:No effect on labor and delivery: No increase in C/S rateNo increase in C/S rate

No increase in forceps/vacuum deliveryNo increase in forceps/vacuum delivery

Patient can ambulatePatient can ambulate

Economical: cost and personnelEconomical: cost and personnel