Background: Obstructive sleep apnea syndrome (OSAS) is present in 44% of patients scheduled for bariatric surgery. Respiratory dysfunction associated with this syndrome is attributable to chronic obstructive pulmonary disease (COPD) and/or obesity hypoventilation syndrome (OHS). We studied the long-term effect of bariatric surgery on weight loss, on the respiratory comorbidities associated with obesity, and on the need for non-invasive positive pressure ventilation.
Methods: We followed a sample of patients with respiratory co-morbidity scheduled for open Capella Roux-en-Y gastric bypass (RYGBP) over 5-years. Patients who were positive for polysomnographic studies and required continous positive airway pressure (CPAP) before surgery were included. All patients were subjected to the same anesthetic and surgical protocols. At 1 year after surgery, polysomnographic studies were performed and arterial blood gases and pulmonary function were tested.
Results: Of the 209 patients scheduled for bariatric surgery during the study period, 105 had respiratory co-morbidity. Of these, 30 required CPAP-BiPAP treatment before surgery and were included in our study. Surgery took 128 minutes (range 70 to 210 minutes). Tracheal extubation in the operating theater was possible for 26 patients (86.7%). During the early postoperative period, 7 patients (23.3%) presented respiratory complications. Length of hospitalization was 6.87 days (range 4 to 11 days). At 1 year after RYGBP, patients presented significant weight loss and improvement of hypoxemia (from 73.3 +/- 10.6 to 90.5 +/- 11.5, P = 0.000), hypercarbia (from 44.5 +/- 5.7 to 40.6 +/- 4.9, P = 0.005), and in spirometric (P = 0.004) and polysomnographic results (P = 0.001). CPAP-BiPAP treatment after weight loss was necessary in only 14% of patients (P = 0.001).
Conclusions: Weight loss after RYGBP improved arterial blood gases, respiratory tests and polysomnographic studies. CPAP treatment can be withdrawn in most patients.