Long-term Improvement of Pulmonary Function after Laparoscopic Gastric Bypass Surgery

INTRODUCTION: Morbidly obese patients often have impaired respiratory mechanics leading to restrictive lung disease. Weight loss after bariatric surgery has been shown to improve or resolve many obesity-related comorbidities; however, little is know about the long-term changes in pulmonary mechanics after bariatric surgery. We hypothesize that pulmonary function may improve with weight loss after laparoscopic gastric bypass.
METHODS: We examined the pulmonary function of 66 consecutive morbidly obese patients before and after laparoscopic gastric bypass. Pulmonary studies, including forced expiratory volume in 1 second (FEV1), forced vital capacity (FVC), peak expiratory flow (PEF), and forced expiratory volume at mid-expiratory phase (FEV 25-75), were measured preoperatively and at 3 month intervals.
RESULTS: There were 51 females and 15 males with a mean age of 40.6 +/- 11.3 years. The mean body mass index was 48 +/- 6.0 kg/m2. The mean percentage of excess body weight loss at 12 months was 67.7+/- 17.9%. The mean preoperative pulmonary function parameters were 2.8 +/- 0.7L for FEV1, 3.1 +/- 0.8 L for FVC, 398.2 +/- 112.6 L/min for PEF, and 3.5 +/- 1.3 L/sec for FEV 25-75. At 12 months postoperatively, FEV1 increased to 10 +/-18 above preoperative value (p=0.04), FVC increased to 7 +/- 33% above of preoperative value (p=0.98), PEF increased to 15 +/-33% above of preoperative value (p=0.08), and FEV 25-75 increased 35 +/- 40% above preoperative value (p=0.002).
CONCLUSIONS: Following laparoscopic gastric bypass surgery, there is a significant improvement in the respiratory mechanics of morbidly obese patients. These improvements may be more prominent in morbidly obese patient with marginal lung function.

Session: Podium Presentation

Program Number: S011

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