Preoxygenation by spontaneous breathing or noninvasive positive pressure ventilation with and without positive end-expiratory pressure: A randomised controlled trial

The objective of this study is to compare the time to achieve an expired O2 fraction FeO2 of 90% (FeO2 90%) during preoxygenation with spontaneous breathing and positive pressure ventilation with and without positive end-expiratory pressure (PEEP). DESIGN: A randomised controlled trial. SETTING: Primary care in a university hospital in France from October 2006 to January 2008. PATIENTS: Adults patients scheduled for elective surgery. Exclusion criteria were rapid sequence induction, anticipated difficult airway management and refusal to provide consent. INTERVENTION: Patients were randomly allocated to preoxygenation with spontaneous breathing or positive pressure ventilation (positive inspiratory pressure: 12 cmH2O) without PEEP and with PEEP (positive inspiratory pressure: 12 cmH2O, PEEP: 6 cmH2O). MAIN OUTCOME MEASURES: Time to achieve an expired O2 fraction of 90% measured from positioning the face mask, and the time it took after endotracheal intubation for the SpO2 to fall to 93% (SpO2 93%) while the patient was apnoeic. Patient discomfort was recorded (visual analogue scale). Data are median (quartile 25th to 75). RESULTS: The time to achieve an FeO2 90% was shorter with positive pressure ventilation, with PEEP [140 (100 to 200) s] and without PEEP [153 (120 to 218) s], than with spontaneous breathing [190 (130 to 264) s; P = 0.002]. At 3 min, 47, 60 and 74% of patients achieved an FeO2 of 90% or more in the spontaneous breathing, positive pressure ventilat...
Source: European Journal of Anaesthesiology - Category: Anesthesiology Tags: Ventilation Source Type: research