Background: Hypoxemia is the most common complication during emergency tracheal intubation of critically ill adults and may increase the risk of cardiac arrest and death. Whether bag-mask ventilation during intubation of critically ill adults prevents hypoxemia without increasing the risk for aspiration remains controversial.
Methods: We conducted a multicenter, two-armed, parallel-group, unblinded randomized controlled trial at seven sites in the United States to compare bag-mask ventilation versus no ventilation between induction (administrative of a sedative agent) and laryngoscopy during rapid sequence intubation of critically-ill adults. By opening opaque envelopes immediately prior to induction, we randomized patients to receive either bag-mask ventilation between induction and laryngoscopy (experimental group) or no ventilation between induction and laryngoscopy (control group). Bag-mask ventilation could be used as a rescue technique in both groups. The primary outcome was the lowest oxygen saturation between induction and two minutes after intubation. The secondary outcome was the incidence of severe hypoxemia, defined as an oxygen saturation <80% between induction and two minutes after intubation. The main safety outcome was aspiration, which was ascertained by both operator report and new chest radiograph opacities within 48 hours.
Results: Among the 401 patients enrolled, median lowest oxygen saturation was 96% [IQR 87-99%] in the bag-mask ventilation group and 93% [IQR 81-99%] in the no ventilation group (P=0.01). Twenty-one patients (10.9%) in the bag-mask ventilation group experienced severe hypoxemia, compared with 45 patients (22.8%) in the no ventilation group (relative risk, 0.48; 95% CI, 0.30 to 0.77; P=0.002). Operator-reported aspiration occurred during 2.5% of intubations in the bag-mask ventilation group, compared to 4.0% in the no ventilation group (P=0.41). The incidence of new opacity on chest radiograph within 48 hours of intubation was 16.4% in the bag-mask ventilation group and 14.8% in the no ventilation group (P=0.73).
Conclusion: Among critically ill adults undergoing emergency tracheal intubation, bag-mask ventilation between induction and laryngoscopy increased oxygen saturation during the procedure without evidence of increasing the incidence of aspiration. (ClinicalTrials.gov number, NCT03026322)