Respiration and ventilation improvement in obese patients

1. OTTIMIZZAZIONE DEGLI SCAMBI
RESPIRATOIRI INTRAOPERATORI ( E
POSTOP…)

2. Intraoperative strategies to improve
oxygenation in morbid obese patients.

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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).

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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.

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.

6. 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.

7. 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.

8. 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.

9. 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…………………

10. 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,
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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
Sleilaty G, Haddad F, Noun R, Madi-Jebara S, Yazbeck P

11. In Group 1 patients, a PEEP of 8mmHg was added to the ventilation
regimen.
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.

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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

14. 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.
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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

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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.

17. 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.

18. 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

19. 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

20. 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

21. Percentage of atelectasis 1 cm above the diaphragm. The application of
RM 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.

22. 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.

23. Postoperative period

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

25. .
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.
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Source
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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:
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26. 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.

27. 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
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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.

28. Anesth technique of Eichelberger et al…
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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.

29. 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)

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

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

32. Postop airway surveillance
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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.