Noninvasive bilevel positive airway pressure for preoxygenation of the critically ill morbidly obese patient

Abstract

Purpose: We describe the use of noninvasive bilevel positive airway pressure (BiPAP) in a critically ill, hypoxemic and morbidly obese patient for preoxygenation prior to rapid sequence induction of anesthesia. Clinical features: A critically ill morbidly obese patient (body mass index: 49 kg·m-2) was scheduled for urgent laparoscopic cholecystectomy. Preoxygenation with 5 L·min-1 oxygen flow resulted in a moderate increase in oxygen saturation (SpO2) from 79percent to 90percent. Prior to rapid sequence induction of anesthesia, a trial of noninvasive BiPAP with oxygen delivery at 5 L·min-1 increased his S pO2 to 95percent initially, with full saturation of 99percent achieved when oxygen flow was increased to 10 L·min-1. Bilevel positive airway pressure with an inspiratory and expiratory pressures of 17 cm H2O and 7 cm H2O, respectively, was applied using a full face mask to achieve a tidal volume of 8 mL·kg-1. Rapid sequence induction proceeded uneventfully. Conclusions: Prior to rapid sequence induction of anesthesia in patients with respiratory compromise secondary to factors which reduce FRC, noninvasive BiPAP in combination with supplemental oxygen may be indicated whenever traditional preoxygenation does not provide adequate oxyhemoglobin saturation. Improved oxygenation is most likely attributable to improved ventilation and alveolar recruitment.