Jean-Luc Hanouz1, Stéphane Lammens, Marine Tasle, Anne Lesage, Jean-Louis Gérard, Benoit Plaud. 1. From the Department of Anaesthesia and Intensive Care Medicine, CHU de Caen (J-LH, AL, J-LG), Department of Anaesthesia, CHP Saint Martin, Caen (SL), Department of Anaesthesia, Hôpitaux du Leman, Thonon-les-Bains (MT), and Department of Anaesthesia and Intensive Care, CHU Saint-Louis Lariboisière Fernand Widal, Assistance Publique - Hôpitaux de Paris, Paris, France (BP).
Abstract
BACKGROUND: In emergency situations requiring rapid airway control, shortening preoxygenate time is desirable. OBJECTIVES: 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 in, 47, 60 and 74% of patients achieved an FeO2 of 90% or more in the spontaneous breathing, positive pressure ventilation without and with PEEP groups, respectively (P = 0.01). Cox proportional-hazards regression showed that positive pressure ventilation with PEEP [hazard ratio 2.18; 95% confidence interval (95% CI) 1.42 to 3.36); P < 0.001] and without PEEP (hazard ratio 1.62; 95% CI 1.05 to 2.50; P = 0.03) were associated with a shorter time to an FeO2 90%. The time until SpO2 93% was not significantly different between spontaneous breathing [305 (263 to 383) s], positive pressure ventilation without PEEP [370 (300 to 450) s] and with PEEP [345 (245 to 435) s; P = 0.08]. The discomfort reported was 0 (0 to 18) mm and was comparable between groups (P = 0.22). CONCLUSION: Compared with spontaneous breathing, positive pressure ventilation with and without PEEP shortened preoxygenation time. TRIAL REGISTRATION: Clinicaltrials.gov identifier: NCT02313766.
RCT Entities:
BACKGROUND: In emergency situations requiring rapid airway control, shortening preoxygenate time is desirable. OBJECTIVES: 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 in, 47, 60 and 74% of patients achieved an FeO2 of 90% or more in the spontaneous breathing, positive pressure ventilation without and with PEEP groups, respectively (P = 0.01). Cox proportional-hazards regression showed that positive pressure ventilation with PEEP [hazard ratio 2.18; 95% confidence interval (95% CI) 1.42 to 3.36); P < 0.001] and without PEEP (hazard ratio 1.62; 95% CI 1.05 to 2.50; P = 0.03) were associated with a shorter time to an FeO2 90%. The time until SpO2 93% was not significantly different between spontaneous breathing [305 (263 to 383) s], positive pressure ventilation without PEEP [370 (300 to 450) s] and with PEEP [345 (245 to 435) s; P = 0.08]. The discomfort reported was 0 (0 to 18) mm and was comparable between groups (P = 0.22). CONCLUSION: Compared with spontaneous breathing, positive pressure ventilation with and without PEEP shortened preoxygenation time. TRIAL REGISTRATION: Clinicaltrials.gov identifier: NCT02313766.