Pulmonary function in morbid obesity

Abstract

Morbid obesity is not infrequently associated with severe respiratory impairment. In our experience approximately 10 per cent of morbidly obese patients who underwent gastric surgery had severe respiratory impairment. Respiratory insufficiency of obesity can be divided into two primary breathing disorders: the obstructive sleep apnea syndrome (SAS) and the obesity hypoventilation syndrome (OHS). In its most severe form, when both SAS and OHS are present, it is called the Pickwickian syndrome. In our series 59 morbidly obese patients with respiratory insufficiency secondary to obesity underwent gastric surgery for weight reduction. Fourteen had OHS, 19 had SAS and 26 had both. Of these, two patients died of postoperative complications and one died at five weeks with an inconclusive autopsy, totalling an operative mortality rate of 3.4 per cent and a total mortality of 5.1 per cent. In our overall experience morbidly obese patients lost 67 per cent of excess weight after gastric procedures. In conclusion, surgically induced weight loss will markedly improve or correct respiratory insufficiency secondary to obesity. It will improve arterial oxygenation, minimize CO2 retention, expand lung volumes, correct polycythemia, and reduce apnea frequency. The magnitude of changes in these variables is clinically significant. Therefore, respiratory insufficiency of obesity should be considered a major indication for an aggressive approach to weight reduction. The jejunoileal bypass and unbanded gastroplasty operations have an unacceptable incidence of complications or failure, respectively. There is a high degree of recidivism following dietary programs. Sweets eaters will not do well with a gastroplasty procedure. Gastric bypass for individuals addicted to sweets or the vertical banded gastroplasty for "gorgers" are currently our procedures of choice and are associated with the average loss of two thirds of excess weight and correction of breathing problems associated with morbid obesity.