Association of Oxygen Mask Type With Incidence of Hypoxia During Emergency Tracheal Intubation: A Secondary Analysis of Two Multicenter Clinical Trials

Abstract RATIONALE: Hypoxemia is a common and life-threatening complication of emergency tracheal intubation. Preoxygenation with supplemental oxygen prior to induction of anesthesia decreases the risk of hypoxemia during intubation. An oxygen mask is the most common method of preoxygenation used in current clinical care. While preoxygenation using noninvasive ventilation has been shown to reduce hypoxemia during intubation compared to preoxygenation with an oxygen mask, noninvasive ventilation may not be suitable for all patients or settings. When an oxygen mask is used, whether the type of mask affects the incidence of hypoxemia is not known.METHODS: We conducted a secondary analysis of the Pragmatic Trial Examining Oxygenation Prior to Intubation (PREOXI) and Direct vs Video Laryngoscope (DEVICE) randomized controlled trials. We compared the incidence of hypoxemia, defined as a peripheral oxygen saturation <85% between induction and 2 minutes after tracheal intubation, between participants preoxygenated with facemask oxygen (either a nonrebreather or facemask without oxygen reservoir) versus a bag-mask device without manual ventilation. The primary analysis was a propensity weighted multivariate logistic regression adjusting for body mass index (BMI), APACHE II score, intubation location (ICU vs ED) and hypoxemic respiratory failure prior to intubation as covariates.RESULTS: Of the 2440 participants enrolled in the PREOXI and DEVICE trials, 1077 were preoxygenated using facemask oxygen and 148 were preoxygenated using a bag-mask device without manual ventilation. The median highest Fraction of Inspired Oxygen (FiO2) prior to intubation was 0.3 (interquartile range [IQR] 0.21 to 0.66) in both the facemask oxygen and bag-mask device groups. A total of 168/1077 (16%) of participants in the facemask oxygen group and 28/148 (19%) of participants in the bag-mask device groups received heated high flow nasal cannula oxygen in the hour prior to intubation. Hypoxemia occurred in 156/1034 (15.1%) participants in the facemask oxygen group and 20/139 (14.4%) participants in the bag-mask device group. In the multivariate analysis, participants preoxygenated with facemask oxygen had similar odds of hypoxemia to those preoxygenated with a bag-mask device (aOR:1.21, 95%CI:[0.70,2.09]). The median lowest oxygen saturation between induction and 2 minutes after tracheal intubation was 97 (IQR 91 to 100) in the facemask oxygen group and 98 (IQR 93 to 100), P=0.33 in the bag-mask device group.CONCLUSIONS: In this secondary analysis of two trials which enrolled critically ill adults undergoing emergency tracheal intubation, preoxygenation with facemask oxygen was not associated with decreased incidence of hypoxemia compared to preoxygenation with a bag-mask device.