Efficacy and safety of patient-controlled analgesia for morbidly obese patients following gastric bypass surgery

Background: Adequate postoperative pain control is important to reduce potential cardiopulmonary complications. It is often difficult to determine dosages of narcotics for morbidly obese patients following Rouxen-Y gastric bypass (RYGBP) due to respiratory depression. Individualization of analgesic therapy, patient-controlled analgesia (PCA), can provide optimal dosage for pain control and minimize the side-effects. Method: 25 morbidly obese patients who received PCA with morphine sulfate following RYGBP. PCA settings we re as follows: morphine, 20 mu g/kg of ideal body weight, 10-minute lock out interval and 80 % of a calculated amount for a 4-hour limit. We measured arterial blood gas, heart rate, mean arterial pressure, arterial oxygen saturation, respiratory rate, opioid amount, patient satisfaction, visual analog pain scale (VAS), and the incidence of nausea, vomiting, pruritus and sedation. Results: Average morphine usage was 44.2+/-28.7 mg during the day of surgery (DOS); 49.1+/-27.4 mg during POD (postoperative day) #1; and 36.6+/-22.8 mg during POD#2 (p < 0.01). 24 patients were satisfied with their pain control on POD#1. VAS was 5.4+/-2.1 on the day of surgery, but remained below 4 thereafter. Arterial oxygen saturation and vital signs were maintained without significant changes. 5 patients experienced mild sedation on the day of surgery and 3 patients experienced mild sedation on POD#1. 1 patient experienced nausea and vomiting and 4 patients had pruritus; however, none required treatment. Conclusion: PCA is safe and effective for morbidly obese patients following RYGBP.