The Particulars: Previous studies suggest that applying positive pressure to the airways can help restore lung volume and capacity and help prevent respiratory complications from abdominal surgery. Little is known about the use of bi-level positive airway pressure (BIPAP) in morbidly obese patients before and after bariatric surgery.

Data Breakdown: For a study, bariatric surgery patients were randomized to receive BIPAP for 1 hour prior to surgery (group 1), 1 hour immediately after surgery (group 2), or 1 hour immediately postoperatively and for 1 hour on the first postoperative day (group 3). All groups experienced significant reductions in slow vital capacity (SVC) scores and inspiratory reserve volume after surgery. Expiratory reserve volume (ERV) was steady in groups 1 and 2, whereas tidal volume (TV) was steady for all groups. The smallest decrease in SVC was in group 2.

Take Home Pearls: Regardless of when it is applied, BIPAP appears to effectively preserve TV following bariatric surgery in morbidly obese patients. BIPAP after surgery appears to promote the smallest reductions in SVC as ERV and TV are restored.