| Abstract: |
Morbid obesity is often associated with severe respiratory insufficiency, commonly known as the pickwickian syndrome. This can be divided into the following two primary breathing disorders which can affect patients alone or in combination: (1) the obstructive sleep apnea syndrome (SAS); and (2) the obesity-hypoventilation syndrome (OHS). Thirty-eight (14 percent) of 263 morbidly obese patients with respiratory insufficiency of obesity underwent gastric surgery for weight reduction. Ten had OHS, nine has SAS, and 19 had both. Of these patients, one died of postoperative complications, one died at five weeks with an inconclusive autopsy, one was lost to follow-up, and the time since surgery was too short (less than three months) in three. A total of 30 patients lost 45±25 percent (p<0.0001) of excess body weight within 3 to 12 months following surgery, when repeat pulmonary studies were done. Most patients continued to lose additional weight until two years, when they had lost 62±26 percent of excess weight. Nine patients failed initial surgery (gastroplasty); seven of these were successfully converted to gastric bypass. Weight loss was associated with a significant decrease in the percentage of sleep apnea from 44±15 to 8±11 (p<0.0001). In patients with OHS, the arterial oxygen pressure (PaO2) increased from 53±9 to 68±11 mm Hg (p<0.0001), and the arterial carbon dioxide tension decreased from 51±7 to 41±4 mm Hg (p<0.0001). Pulmonary function tests in the patients with OHS revealed significant increases, as a percentage of predicted normal, in the forced vital capacity, forced expiratory volume in one second, expiratory reserve volume, functional residual capacity, and total lung capacity. Secondary polycythemia, defined as a hemoglobin level greater than 16 g/dl associated with a PaO2less than 60 mm Hg, was noted in 13 of 29 patients with OHS. This fell from 16.9±1.1 to 14.9±1.7 g/dl (p<0.001) after weight loss and improved pulmonary function. |
