Comparison of pulmonary function and postoperative pain after laparoscopic versus open gastric bypass: a randomized trial

J Am Coll Surg. 2001 Apr;192(4):469-76; discussion 476-7. doi: 10.1016/s1072-7515(01)00822-5.


Background: Impairment of pulmonary function is common after upper abdominal operations. The purpose of this study was to compare postoperative pulmonary function and analgesic requirements in patients undergoing either laparoscopic or open Roux-en-Y gastric bypass (GBP).

Study design: Seventy patients with a body mass index of 40 to 60 kg/m2 were randomly assigned to undergo laparoscopic (n = 36) or open (n = 34) GBP. The two groups were similar in age, gender, body mass index, pulmonary history, and baseline pulmonary function. Pulmonary function studies were performed preoperatively and on postoperative days 1, 2, 3, and 7. Oxygen saturation and chest radiographs were performed on both groups preoperatively and on postoperative day 1. Postoperative pain was evaluated using a visual analog scale and the amount of narcotic consumed was recorded. Data are presented as mean +/- standard deviation.

Results: Laparoscopic GBP patients had significantly less impairment of pulmonary function than open GBP patients on the first three postoperative days (p < 0.05). By the 7th postoperative day, all pulmonary function parameters in the laparoscopic GBP group had returned to within preoperative levels, but only one parameter (peak expiratory flow) had returned to preoperative levels in the open GBP group. On the first postoperative day, laparoscopic GBP patients used less morphine than open GBP patients (46 +/- 31 mg versus 76 +/- 39 mg, respectively, p < 0.001), and visual analog scale pain scores at rest and during mobilization were lower after laparoscopic GBP than after open GBP (p < 0.05). Fewer patients after laparoscopic GBP than after open GBP developed hypoxemia (31% versus 76%, p < 0.001) and segmental atelectasis (6% versus 55%, p = 0.003).

Conclusion: Laparoscopic gastric bypass resulted in less postoperative suppression of pulmonary function, decreased pain, improved oxygenation, and less atelectasis than open gastric bypass.

Publication types

  • Clinical Trial
  • Comparative Study
  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Analgesics, Opioid / therapeutic use
  • Analysis of Variance
  • Blood Gas Analysis
  • Body Mass Index
  • Female
  • Forced Expiratory Volume*
  • Gastric Bypass / adverse effects*
  • Gastric Bypass / methods
  • Humans
  • Laparoscopy / adverse effects*
  • Laparoscopy / methods
  • Male
  • Middle Aged
  • Morphine / therapeutic use
  • Obesity, Morbid / diagnosis
  • Obesity, Morbid / metabolism
  • Obesity, Morbid / physiopathology
  • Obesity, Morbid / surgery
  • Pain Measurement
  • Pain, Postoperative / diagnosis
  • Pain, Postoperative / drug therapy
  • Pain, Postoperative / etiology*
  • Peak Expiratory Flow Rate*
  • Pulmonary Atelectasis / diagnostic imaging
  • Pulmonary Atelectasis / etiology
  • Radiography
  • Respiratory Function Tests
  • Time Factors
  • Treatment Outcome
  • Vital Capacity*


  • Analgesics, Opioid
  • Morphine