OTTIMIZZAZIONE DEGLI SCAMBI RESPIRATOIRI INTRAOPERATORI ( E POSTOP…)

Intraoperative strategies to improve oxygenation in morbid obese patients.

• Control of Ventilation• The control of ventilation during surgery, specifically during laparoscopic surgery in MO patients has been• carefully evaluated (40). It is well known that closing volumes can exceed functional residual capacity, causing• airway closure and resulting in an increased alveolar/arterial difference in oxygen tension in MO patients under• anesthesia. Using PEEP slightly improves PaO2 (from 110 to 130 mm Hg) but might be limited by hypotension if• the patient is not well hydrated. The beach chair position and PEEP were particularly effective on respiratory• mechanics and lung volumes in MO patients during pneumoperitoneum (41). Arterial oxygenation during• laparoscopy is affected by body weight and improved by increasing the FiO2; it could not be improved by

increasing• either tidal volume or respiratory rate. PaO2 is not affected by the Trendelenburg position (42). During laparotomy• surgery, the reverse Trendelenburg is appropriate for hydrated obese patients because it causes only minimal

arterial• blood pressure changes and improves oxygenation (43). Recently, pressure-controlled ventilation has been studied• in 36 MO patients and has been shown to improve oxygenation without side effects compared with

volumecontrolled• ventilation (44).

• 40. Pelosi P, Ravagnan I, Girati G, Panigada M, Bottino N, Tredici S, Eccher G, Gattinoni L. Positive endexpiratory• pressure improves respiratory function in obese but not in normal subjects during anesthesia and• paralysis. Anesthesiology 1999;91(5):1221-31.• 41. Valenza F, Vagginelli F, Tiby A, Francesconi S, Ronzoni G, Guglielmi M, Zappa M, Lattuada E, Gattinoni L.• Effects of the beach chair position, positive end-expiratory pressure, and pneumoperitoneum on respiratory• function in morbidly obese patients during anesthesia and paralysis. Anesthesiology 2007;107(5):725-32.• 42. Sprung J, Whalley DG, Falcone T, Wilks W, Navratil JE, Bourke DL. The effects of tidal volume and• respiratory rate on oxygenation and respiratory mechanics during laparoscopy in morbidly obese patients.• Anesthesia & Analgesia 2003;97:268-74.• 43. Perilli V, Sollazzi L, Bozza P, Modesti C, Chierichini A, Tacchino RM, Ranieri R. The effects of the reverse• trendelenburg position on respiratory mechanics and blood gases in morbidly obese patients during bariatric• surgery. Anesthesia & Analgesia 2000;91:1520-5.• 44. Cadi P, Guenoun T, Journois D, Chevallier JM, Diehl JL, Safran D. Pressure-controlled ventilation improves• oxygenation during laparoscopic obesity surgery compared with volume-controlled ventilation. Br J Anaesth• 2008;100(5):709-16.• 45. Neligan PJ, Malhotra G, Fraser M, Williams N, Greenblatt EP, Cereda M, Ochroch EA. Noninvasive ventilation• immediately after extubation improves lung function in morbidly obese patients with obstructive sleep apnea• undergoing laparoscopic bariatric surgery. Anesth Analg 2010;110(5):1360-5.

Sprung, J. et al. The Effects of Tidal Volume and Respiratory Rate on Oxygenation and Respiratory Mechanics During Laparoscopy in Morbidly Obese Patients. Anesth Analg

2003; 97:268-274.

Sprung, J. et al. The Effects of Tidal Volume and Respiratory Rate on Oxygenation and Respiratory Mechanics During Laparoscopy in

Morbidly Obese Patients. Anesth Analg 2003; 97:268-274.

Sprung, J. et al. The Effects of Tidal Volume and Respiratory Rate on Oxygenation and Respiratory Mechanics During Laparoscopy in

Morbidly Obese Patients. Anesth Analg 2003; 97:268-274.

Sprung, J. et al. The Effects of Tidal Volume and Respiratory Rate on Oxygenation and Respiratory Mechanics During Laparoscopy in

Morbidly Obese Patients. Anesth Analg 2003; 97:268-274.

Conclusions:Sprung, J. et al. The Effects of Tidal Volume and Respiratory Rate on Oxygenation and Respiratory Mechanics

During Laparoscopy in Morbidly Obese Patients. Anesth Analg 2003; 97:268-274.

• Under baseline conditions, Fio2 0.5, VT 10 mL/kg ideal body weight, RR 10 breaths/min, I/E 1:2.5 + PEEP 5 cmH2O Pao2 was significantly worse in MO patients than in NW patients, Pao2 172 47 mm Hg versus 260 21

• Surprisingly, oxygenation was not further adversely affected either by body position, pneumoperitoneum, or a combination of both.

• Under each of these conditions, increasing the minute ventilation by either doubling the VT or the RR failed to produce any improvement in oxygenation. settings were

• probably closer to optimal values and thus little improvement could be expected with increases in either VT or RR…………………

Eur J Anaesthesiol. 2007 Mar;24(3):283-8. Effect of vital capacity manoeuvres on arterial oxygenation in morbidly obese patients undergoing open bariatric surgery.Chalhoub V, Yazigi A,

Sleilaty G, Haddad F, Noun R, Madi-Jebara S, Yazbeck P • .• Source• Hotel Dieu de France Hospital, Department of Anaesthesia and Critical Care, Beirut, Lebanon. vivchalhoub@yahoo.com• Abstract• BACKGROUND: • Arterial oxygenation may be compromised in morbidly obese patients undergoing bariatric surgery. The aim of this study was to

evaluate the effect of a vital capacity manoeuvre (VCM), followed by ventilation with positive end-expiratory pressure (PEEP), on arterial oxygenation in morbidly obese patients undergoing open bariatric surgery.

• METHODS: • Fifty-two morbidly obese patients (body mass index >40 kg m-2) undergoing open bariatric surgery were enrolled in this

prospective and randomized study. Anaesthesia and surgical techniques were standardized. Patients were ventilated with a tidal volume of 10 mL kg-1 of ideal body weight, a mixture of oxygen and nitrous oxide (FiO2 = 40%) and respiratory rate was adjusted to maintain end-tidal carbon dioxide at a level of 30-35 mmHg. After abdominal opening, patients in Group 1 had a PEEP of 8 cm H2O applied and patients in Group 2 had a VCM followed by PEEP of 8 cm H2O. This manoeuvre was defined as lung inflation by a positive inspiratory pressure of 40 cm H2O maintained for 15 s. PEEP was maintained until extubation in the two groups. Haemodynamics, ventilatory and arterial oxygenation parameters were measured at the following times: T0 = before application of VCM and/or PEEP, T1 = 5 min after VCM and/or PEEP and T2 = before abdominal closure.

• RESULTS: • Patients in the two groups were comparable regarding patient characteristics, surgical, haemodynamic and ventilatory parameters.

In Group 1, arterial oxygen partial pressure (PaO2) and arterial haemoglobin oxygen saturation (SaO2) were significantly increased and alveolar-arterial oxygen pressure gradient (A-aDO2) decreased at T2 when compared with T0 and T1. In Group 2, PaO2 and SaO2 were significantly increased and A-aDO2 decreased at T1 and T2 when compared with T0. Arterial oxygenation parameters at T1 and T2 were significantly improved in Group 2 when compared with Group 1.

• CONCLUSION: • The addition of VCM to PEEP improves intraoperative arterial oxygenation in morbidly obese patients undergoing open bariatric

surgery

In Group 1 patients, a PEEP of 8mmHg was added to the ventilationregimen.

In Group 2 patients, a VCM was applied before adding a PEEP of 8 cmH2O to the ventilation regimen. The VCM was performed by inflating the lungs to a peak airway pressure of 40 cmH2O

and maintaining this pressure for 15 s. VCM and/or PEEP were applied 10 min after abdominal opening and reverse Trendelenburg positioning of the patient. PEEP was maintained until tracheal extubation.

T0:before the application of VCM and/or PEEP,T1:10 min after the application of VCM and/or PEEP T2:at the end of surgery before abdominal closure.

• Anesth Analg. 2009 Nov;109(5):1511-6.• Intraoperative ventilatory strategies for prevention of pulmonary atelectasis in obese patients undergoing laparoscopic bariatric surgery.• Talab HF, Zabani IA, Abdelrahman HS, Bukhari WL, Mamoun I, Ashour MA, Sadeq BB, El Sayed SI.• Source• Department of Anesthesiology, King Faisal Specialist Hospital & Research Centre, Jeddah, Saudi Arabia.• Abstract• BACKGROUND: • Atelectasis occurs regularly after induction of general anesthesia, persists postoperatively, and may contribute to significant postoperative morbidity

and additional health care costs. Laparoscopic surgery has been reported to be associated with an increased incidence of postoperative atelectasis. It has been shown that during general anesthesia, obese patients have a greater risk of atelectasis than nonobese patients. Preventing atelectasis is important for all patients but is especially important when caring for obese patients.

• METHODS: • We randomly allocated 66 adult obese patients with a body mass index between 30 and 50 kg/m(2) scheduled to undergo laparoscopic bariatric

surgery into 3 groups. According to the recruitment maneuver used, the zero end-expiratory pressure (ZEEP) group (n = 22) received the vital capacity maneuver (VCM) maintained for 7-8 s applied immediately after intubation plus ZEEP; the positive end-expiratory pressure (PEEP) 5 group (n = 22) received the VCM maintained for 7-8 s applied immediately after intubation plus 5 cm H(2)O of PEEP; and the PEEP 10 group (n = 22) received the VCM maintained for 7-8 s applied immediately after intubation plus 10 cm H(2)O of PEEP. All other variables (e.g., anesthetic and surgical techniques) were the same for all patients. Heart rate, noninvasive mean arterial blood pressure, arterial oxygen saturation, and alveolar-arterial Pao(2) gradient (A-a Pao(2)) were measured intraoperatively and postoperatively in the postanesthesia care unit (PACU). Length of stay in the PACU and the use of a nonrebreathing O(2) mask (100% Fio(2)) or reintubation were also recorded. A computed tomographic scan of the chest was performed preoperatively and postoperatively after discharge from the PACU to evaluate lung atelectasis.

• RESULTS: • Patients in the PEEP 10 group had better oxygenation both intraoperatively and postoperatively in the PACU, lower atelectasis score on chest

computed tomographic scan, and less postoperative pulmonary complications than the ZEEP and PEEP 5 groups. There was no evidence of barotrauma in any patient in the 3 study groups.

• CONCLUSIONS: • Intraoperative alveolar recruitment with a VCM followed by PEEP 10 cm H(2)O is effective at preventing lung atelectasis and is associated with better

oxygenation, shorter PACU stay, and fewer pulmonary complications in the postoperative period in obese patients undergoing laparoscopic bariatric surgery

Anesthesiology. 2009 Nov;111(5):979-87.Prevention of atelectasis in morbidly obese patients during

general anesthesia and paralysis: a computerized tomography study.

Reinius H, Jonsson L, Gustafsson S, Sundbom M, Duvernoy O, Pelosi P, Hedenstierna G, Fredén F.• Source

• Department of Anesthesia and Intensive Care, University Hospital, Uppsala, Sweden. henrik.reinius@surgsci.uu.se• Abstract• BACKGROUND: • Morbidly obese patients show impaired pulmonary function during anesthesia and paralysis, partly due to

formation of atelectasis. This study analyzed the effect of general anesthesia and three different ventilatory strategies to reduce the amount of atelectasis and improve respiratory function.

• METHODS: • Thirty patients (body mass index 45 +/- 4 kg/m) scheduled for gastric bypass surgery were prospectively

randomized into three groups: (1) positive end-expiratory pressure of 10 cm H2O (PEEP), (2) a recruitment maneuver with 55 cm H2O for 10 s followed by zero end-expiratory pressure, (3) a recruitment maneuver followed by PEEP. Transverse lung computerized tomography scans and blood gas analysis were recorded: awake, 5 min after induction of anesthesia and paralysis at zero end-expiratory pressure, and 5 min and 20 min after intervention. In addition, spiral computerized tomography scans were performed at two occasions in 23 of the patients.

• RESULTS: • After induction of anesthesia, atelectasis increased from 1 +/- 0.5% to 11 +/- 6% of total lung volume (P < 0.0001).

End-expiratory lung volume decreased from 1,387 +/- 581 ml to 697 +/- 157 ml (P = 0.0014). A recruitment maneuver + PEEP reduced atelectasis to 3 +/- 4% (P = 0.0002), increased end-expiratory lung volume and increased Pao2/Fio2 from 266 +/- 70 mmHg to 412 +/- 99 mmHg (P < 0.0001). PEEP alone did not reduce the amount of atelectasis or improve oxygenation. A recruitment maneuver + zero end-expiratory pressure had a transient positive effect on respiratory function. All values are presented as mean +/- SD.

• CONCLUSIONS: • A recruitment maneuver followed by PEEP reduced atelectasis and improved oxygenation in morbidly obese

patients, whereas PEEP or a recruitment maneuver alone did not

• Cochrane Database Syst Rev. 2010 Sep 8;(9):CD007922.• Positive end-expiratory pressure (PEEP) during anaesthesia for the prevention of mortality and postoperative pulmonary complications.• Imberger G, McIlroy D, Pace NL, Wetterslev J, Brok J, Møller AM.• Source• The Cochrane Anaesthesia Review Group, Rigshospitalet, Blegdamsvej 9,, Afsnit 3342, København, Denmark, 2100.• Abstract• BACKGROUND: • General anaesthesia causes atelectasis which can lead to impaired respiratory function. Positive end-expiratory pressure (PEEP) is a mechanical

manoeuvre which increases functional residual capacity (FRC) and prevents collapse of the airways thereby reducing atelectasis. It is not known whether intra-operative PEEP alters the risk of postoperative mortality and pulmonary complications.

• OBJECTIVES: • To assess the benefits and harms of intraoperative PEEP, for all adult surgical patients, on postoperative mortality and pulmonary outcomes.• SEARCH STRATEGY: • We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2009, Issue 4), MEDLINE (via Ovid) (1966 to January

2010), EMBASE (via Ovid) (1980 to January 2010), CINAHL (via EBSCOhost) (1982 to January 2010), ISI Web of Science (1945 to January 2010) and LILACS (via BIREME interface) (1982 to January 2010).

• SELECTION CRITERIA: • We included randomized clinical trials that evaluated the effect of PEEP versus no PEEP, during general anaesthesia, on postoperative mortality and

postoperative respiratory complications. We included studies irrespective of language and publication status.• DATA COLLECTION AND ANALYSIS: • Two investigators independently selected papers, extracted data that fulfilled our outcome criteria and assessed the quality of all included trials. We

undertook pooled analyses, where appropriate. For our primary outcome (mortality) and two secondary outcomes (respiratory failure and pneumonia), we calculated the number of further patients needed (information size) in order to make reliable conclusions.

• MAIN RESULTS: • We included eight randomized trials with a total of 330 patients. Two trials had a low risk of bias. There was no difference demonstrated for mortality

(relative risk (RR) 0.95, 95% CI 0.14 to 6.39). Two statistically significant results were found: the PEEP group had a higher PaO(2)/FiO(2) on day 1 postoperatively (mean difference (MD) 22.98, 95% CI 4.40 to 41.55) and postoperative atelectasis (defined as an area of collapsed lung, quantified by computerized tomography (CT) scan) was less in the PEEP group (SMD -1.2, 95% CI -1.78 to -0.79). There were no adverse events reported in the three trials that adequately measured these outcomes (barotrauma and cardiac complications). Using information size calculations, we estimated that a further 21,200 patients would need to be randomized in order to make a reliable conclusion about PEEP and mortality.

• AUTHORS' CONCLUSIONS: • There is currently insufficient evidence to make conclusions about whether intraoperative PEEP alters the risk of postoperative mortality and

respiratory complications among undifferentiated surgical patients

Anesthesiology. 2009 Nov;111(5):979-87.Prevention of atelectasis in morbidly obese patients during general anesthesia and

paralysis: a computerized tomography study.Reinius H, Jonsson L, Gustafsson S, Sundbom M, Duvernoy O, Pelosi P,

Hedenstierna G, Fredén F

• (1) PEEP: PEEP of 10 cm H2O; • (2) RMZEEP: recruitment maneuver followed by ZEEP; • (3) RMPEEP: Recruitment maneuver followed by PEEP of 10

cm H2O.• recruitment maneuver: ventilator mode was switched to

pressure control, inspiratory pressure was increased to 55 cm H2O, and an inspiratory hold was kept for 10 s.

• In case of a drop in systolic blood pressure by more than 20%,the ecruitment maneuver would have been disrupted.

• In the recruitment maneuver followed by PEEP group,PEEP was applied immediately after the recruitment maneuver.

• Measurements were obtained: (1) before anesthesia induction, (2) 5 min after induction and tracheal intubation, and (3) 5 min, (4) 20 min, and (5) 40 min after intervention.

Anesthesiology. 2009 Nov;111(5):979-87..Prevention of atelectasis in morbidly obese patients during general anesthesia and paralysis: a computerized tomography study.Reinius H, Jonsson L, Gustafsson S, Sundbom M,

Duvernoy O, Pelosi P, Hedenstierna G, Fredén F

Induction of anesthesia caused a reduction of PaO2/FIO2. In the RM PEEP group(n 10), oxygenation returned to the same level as before induction of anesthesia. In the groups with RM ZEEP (n 10) or PEEP (n 10), there was no significant effect on oxygenation Anesthesiology.

2009 Nov;111(5):979-87..Prevention of atelectasis in morbidly obese patients during general anesthesia and paralysis: a computerized tomography study.Reinius H, Jonsson L, Gustafsson S, Sundbom M, Duvernoy O, Pelosi P, Hedenstierna G, Fredén F

induction of anesthesia and paralysis was accompanied by approximately 50% reduction of EELV. Twenty minutes after intervention, the EELV increased 32% in the PEEP group and 64% in the recruitment maneuver followed by PEEP group. No changes in EELV were observed after a recruitment maneuver followed by

ZEEP

Percentage of atelectasis 1 cm above the diaphragm. The application ofRM PEEP (n 10) reduced atelectasis, and this effect was sustained for 20 min. RM

ZEEP (n 10) caused a reduction of atelectasis, but this effect could not be seen after 20 min. PEEP(n 10) had no effect on the amount of atelectasis.

Representative computerized tomography (CT). A CT scan 1 cm above the diaphragm in the three different groups at all four time points. Note the sustained effect of RM PEEP and the

transient effect of RM ZEEP.

Postoperative period

• Postoperative hypoxemia in morbidly obese patients with and without obstructive sleep apnea undergoing laparoscopic bariatric surgery

.Ahmad S, Nagle A, McCarthy RJ, Fitzgerald PC, Sullivan JT,

Prystowsky .JPostoperative hypoxemia in morbidly obese patients with and without obstructive sleep apnea undergoing laparoscopic bariatric surgery.

Anesth Analg. 2008 Jul;107(1):138-43.• .• Source

• Department of Anesthesiology, Northwestern University Feinberg School of Medicine, 251 E. Huron St., F5-704 Chicago, IL 0 60611, USA. sah704@northwestern.edu

• Abstract• INTRODUCTION: • The increased incidence of morbid obesity has resulted in an increase of bariatric surgical procedures. Obstructive sleep apnea (OSA) is a commonly

encountered comorbidity in morbidly obese patients. Sedatives, analgesics, and anesthetics alter airway tone, and airway obstruction and death have been reported in patients with OSA after minimal doses of sedatives and anesthetics, yet there is a lack of consensus regarding the care of these patients. In this study, we sought to determine whether obese patients with polysomnography-confirmed diagnosis of OSA were at significantly greater risk for postoperative hypoxemic episodes in the first 24 h after laparoscopic bariatric surgery than morbidly obese patients without a diagnosis of OSA.

• METHODS: • Adult subjects (Body Mass Index, 35-75 kg/m(2)) scheduled to undergo laparoscopic bariatric surgery were studied. A finger pulse oximetry probe was

placed preoperatively and oxygen saturation (Spo(2)) was recorded continuously. All subjects underwent preoperative polysomnography testing within 4 wk of surgery. Anesthetic management was standardized, using propofol for induction and desflurane and remifentanil for maintenance of anesthesia. Patient-controlled analgesia programmed to deliver morphine, 1 mg. every 10 minutes, was used for pain management postoperatively. Hypoxemic episodes were scored as Spo(2) >4% below the polysomnography study baseline and lasting for more than 10 s.

• RESULTS: • Eight men and 32 women were enrolled and 1 subject had incomplete data. Thirty-one of the 40 subjects had

polysomnography-confirmed OSA. Eight subjects used home continuous positive airway pressure devices nightly, and six of these used their device postoperatively. Preoperatively, subjects with OSA had lower nadir Spo(2) during the polysomnography study and a larger number had an apnea/hypopnea index >10 episodes per hour compared with the non-OSA group. In the first 24 h postoperatively, there was no difference in the median Spo(2) with and without oxygen therapy, between OSA and non-OSA groups. The number of episodes of oxygen desaturation >4% below the polysomnography study baseline value and the mean number of desaturation episodes per hour did not differ between the groups.

• CONCLUSIONS: • In morbidly obese subjects, in the first 24 h after laparoscopic bariatric surgery, OSA does not seem to increase the risk of

postoperative hypoxemia. Our data confirm that morbidly obese subjects, with or without OSA, experience frequent oxygen desaturation episodes postoperatively, despite supplemental oxygen therapy suggesting that perioperative management strategies in morbidly obese patients undergoing laparoscopic bariatric surgery should include measures to prevent postoperative hypoxemia.

Ahmad S, Nagle A, McCarthy RJ, Fitzgerald PC, Sullivan JT, Prystowsky .JPostoperative hypoxemia in morbidly obese patients with and without obstructive sleep apnea undergoing laparoscopic bariatric surgery.

Anesth Analg. 2008 Jul;107(1):138-43.

• no significant differences in the hourly frequency (ODI) or the total number of desaturation episodes

• during the first 24 h after laparoscopic bariatric surgery between obese subjects with OSA and obese subjects without OSA.

• Median Spo2 with and without supplemental oxygen therapy and the duration that the Spo2 was below 90% also did not differ between groups. Taken together, these findings suggest that OSA per se does not seem to be an independent risk of the occurrence of episodic hypoxemia in this subset of patients.

• Despite supplemental administration of oxygen, morbidly obese subjects with or without OSA experienced frequent desaturation episodes. These data suggest th at perioperative management strategies for patients undergoing laparoscopic bariatric surgery should include measures to detect and prevent postoperative hypoxemia but that there may not need to be additional modifications for subjects with OSA.

Eichenberger AS, Proitti S, Frascarolo P, Suter M, Spahn DR,Magnusson L. Morbid obesity and postoperative pulmonary atelectasis: an

underestimated problem. Anesth Analg 2002;95:1788–92

• Department of Anesthesiology, University Hospital, Lausanne, Switzerland.• Abstract• Perturbation of respiratory mechanics produced by general anesthesia and surgery is more

pronounced in morbidly obese (MO) patients. Because general anesthesia induces pulmonary atelectasis in nonobese patients, we hypothesized that atelectasis formation would be particularly significant in MO patients. We investigated the importance and resorption of atelectasis after general anesthesia in MO and nonobese patients. Twenty MO patients were anesthetized for laparoscopic gastroplasty and 10 nonobese patients for laparoscopic cholecystectomy. We assessed pulmonary atelectasis by computed tomography at three different periods: before the induction of general anesthesia, immediately after tracheal extubation, and 24 h later. Already before the induction of anesthesia, MO patients had more atelectasis, expressed in the percentage of the total lung area, than nonobese patients (2.1% versus 1.0%, respectively; P < 0.01). After tracheal extubation, atelectasis had increased in both groups but remained significantly more so in the MO group (7.6% for MO patients versus 2.8% for the nonobese; P < 0.05). Twenty-four hours later, the amount of atelectasis remained unchanged in the MO patients, but we observed a complete resorption in nonobese patients (9.7% versus 1.9%, respectively; P < 0.01). General anesthesia in MO patients generated much more atelectasis than in nonobese patients. Moreover, atelectasis remained unchanged for at least 24 h in MO patients, whereas atelectasis disappeared in the nonobese. IMPLICATIONS: We compared the resolution over time of pulmonary atelectasis after a laparoscopic procedure by performing computed tomography scans in two different groups of patients: 1 group had 10 nonobese patients, and in the other group there were 20 morbidly obese patients.

Anesth technique of Eichelberger et al…• No premedication was given. General anesthesia• was induced after 5 min of breathing 100% oxygen• with 2 mg/kg of propofol and 0.75 g/kg of remifentanil• during the first 45 s, followed by an infusion of• 0.1–0.5 g · kg1 · min1. Maintenance of anesthesia• was obtained with desflurane and remifentanil. The• dosage of these drugs was adjusted to achieve a clinically• adequate depth of anesthesia. During induction,• the lungs were ventilated manually via a face mask• with 100% oxygen. To facilitate orotracheal intubation,• patients received 0.2 mg/kg of cisatracurium; additional• doses of 1–4 mg were given when needed. The• patients were mechanically ventilated with 50% oxygen• in nitrogen with a tidal volume of 10 mL/kg in the• nonobese patients and 10 mL/kg of ideal body weight• for the MO group. The respiratory rate was adjusted• to maintain an end-tidal carbon dioxide concentration• of 35–45 mm Hg with an inspiratory/expiratory ratio• of 1:2. A positive end-expiratory pressure of 6 cm H2O• was applied in both groups. At the end of surgery, any• residual effect of the muscle relaxant was reversed by• 2.5 mg of neostigmine and 0.25 mg of glycopyrronium.• Postoperative analgesia was provided by 2 g of• propacetamol, 30 mg of ketorolac, and 0.1 mg/kg of• morphine given 30 min before the end of the surgical• procedure. Ten minutes before extubation, all patients• were given 100% oxygen. After extubation, all patients• were spontaneously breathing with a face mask (providing• a fraction of inspired oxygen [Fio2] of 0.5) for• 2 h or more when required. Postoperative analgesics• consisted of propacetamol 2 g four times per day and• ketorolac 30 mg three times per day. Metamizole• 500 mg three times per day was added if needed in• both groups.• During the surgical procedure, the peritoneum was• insufflated with CO2 by a WOLF gas insufflator• (Treier Endoscopie, Berommunster, Switzerland) up• to an intraperitoneal peak pressure of 15 mm Hg.• Patients were excluded from the study if the procedure• was converted to laparotomy.

Anesth Analg. 2002 Dec;95(6):1788-92,Morbid obesity and postoperative pulmonary atelectasis: an underestimated problem.Eichenberger A, Proietti S,

Wicky S, Frascarolo P, Suter M, Spahn DR, Magnusson L.

Gastric bypass or bending vs cholecystectomy(non obese)

CAT at the level of the interventricular septum;at induction,extubation,24 hr later

Vedere Obesity and respiratory disease Zammit et al nel *** .docx.

Postop airway surveillance • Airway changes in this population are also of concern outside the operative arena. Since bariatric surgical patients

have a 39-71% incidence of obstructive sleep apnea,[7] we established a questionnaire for the Pre-Anesthesia Clinic (PAC) to predict a surgical patient’s risk for obstructive sleep apnea and need for further evaluation by a cardiologist and pulmonologist. Patients opting for bariatric corrective surgery and those with Class 3 morbid obesity (BMI>40) and super obesity (BMI>55) for any surgery are automatically referred to a pulmonologist for pre-operative evaluation.

• We also use guidelines for post-operative monitoring and initial disposition of obese patients based on a scoring system designed to estimate the peri-operative risk of complications. Ideally this determination is made prior to the day of surgery, but if this fails to occur, then the anesthesiologist and surgeon together may elect presumptive management based on clinical criteria, or may delay surgery to allow time for further evaluation of the problem.

• Three major factors we examine include the severity of sleep apnea, the type of surgery, and the anticipated need for post-operative opioids. We determine the total OSA score by adding the score from the first criterion to the higher of the last two criteria. This score is adjusted slightly based upon any intra or post-operative problems and home support capabilities such as familiarity with CPAP and its use. To be a potential outpatient surgical candidate, a patient needs a score no greater than 4 out of 6. Though such patients may be at increased perioperative risk from obstructive sleep apnea, they can usually be discharged to home or to the routine ward depending on the clinical risk evaluation. Patients with a score of 5 out of 6 could be at significant risk for complications and should be considered for direct observation in monitored beds rather than the routine ward. This is based, once again, on clinical circumstances.

• Patients with scores of 6 out of 6 are routinely monitored in a direct observation area with telemetry monitoring. There is consensus among many experts that simple oxygen saturation monitoring in an isolated room on a ward is not sufficient in these patients. Observational units, but not necessarily ICU’s, with RN: patient ratios of 1: 3-4 are needed along with frequent visual observation and EKG, noninvasive blood pressure and telemetry oxygen saturation monitors. Although we currently only use this protocol for obstructive sleep apnea patients undergoing total joint replacements, we may extend this program to other patients if it proves beneficial.