Patients-Controlled Epidural Analgesia After Gastric Bypass for Morbid Obesity Using Morphine-Levobupivacaine Regimens

Adequate postoperative analgesia can facilitate recovery following gastric bypass surgery for morbid obesity. The efficacy and safety of intravenous patient - controlled analgesia has been studied, but up to date no data are available concerning the use of thoracic epidural patient-controlled analgesia regarding the use of levobupivacaine combined with morphine in morbidly obese patients. The investigators' aim in this prospective, randomized, double-blinded study was to compare the analgesic effectiveness, the dose requirements and side effects of thoracic epidural patient controlled analgesia 0.1% and 0.2% levobupivacaine combined with a continuous epidural administration of morphine, with or without a loading dose, after open gastric bypass for morbid obesity.

Morbidly obese patients (BMI \> 50 kg/m2) planned to undergo open variant of biliopancreatic diversion with Roux-en-Y gastric bypass (BPD-RYGBP) received standardized general anesthesia (intravenous propofol combined with remifentanyl and muscle relaxation). Preoperatively, in all patients an epidural catheter in the thoracic spine level will be placed between T5 and T8 interspace. All patients will be randomly allocated to six groups:

Group A patients will receive intra-operatively (45 min before the estimated end of the surgery) a bolus dose 2 ml of normal saline, epidurally. Postoperatively, immediately after extubation patient controlled epidural anesthesia (PCEA)with 0.1% levobupivacaine (5ml, lockout interval 10min) , combined with a continuous epidural infusion of morphine 0.2 mg/h will be administered, Group B patients will receive an epidural bolus dose of 1mg of morphine intra-operatively (45 min before the estimated end of the surgery) and postoperatively the same levobupivacaine and morphine regimen as Group A, Group C patients will receive an epidural bolus dose 2 mg of morphine intra-operatively and thereafter the same levobupivacaine and morphine regimen as Group A.

Group D patients will receive intra-operatively an epidural bolus dose of 2 ml of normal saline. Postoperatively, the patients will receive PCEA in a dose of 0.2% levobupivacaine (5ml, lockout interval 10min) combined with a continuous epidural infusion of morphine 0.2 mg/h, Group E patients will receive intra-operatively an epidural bolus dose of 1mg of morphine intra-operatively and postoperatively the same regimen as Group D.

Group F patients will receive intra-operatively an epidural bolus dose of 2 mg of morphine intra-operatively and thereafter the same regimen as Group D.

Pain assessment will be performed using visual analogue scale (VAS, 10cm scale) at rest, at mobilization and at cough. Furthermore, total local anesthetic and morphine consumption, side effects on cardiovascular, respiratory and gastrointestinal systems, including blood pressure,blood gases, spirometric values Forced Expiratory Volume at 1 sec (FEV1), Forced Vital Capacity (FVC), Peak Expiratory Flow Rate (PEFR), incidents of postoperative nausea and vomiting (PONV), pruritus, time to first flatus, postoperative ambulation will be recorded for up to 6 days.

Eligibility Criteria:
Inclusion Criteria:

* Body mass index (BMI) \> 50
* Age \< 50
* Patients written consent to participate in the study

Exclusion Criteria:

* Cardiovascular disease (valvular and ischemic heart disease)
* Patients refusal to participate in the study
* Contraindication to epidural catheter placement (e.g anticoagulation, anti- platelets medication)
* Active psychiatric disease requiring treatment
* Redo surgery