Noninvasive Ventilation for Preoxygenation during Emergency Intubation

Abstract

Background: Among critically ill adults undergoing tracheal intubation, hypoxemia increases the risk of cardiac arrest and death. The effect of preoxygenation with noninvasive ventilation, as compared with preoxygenation with an oxygen mask, on the incidence of hypoxemia during tracheal intubation is uncertain.

Methods: In a multicenter, randomized trial conducted at 24 emergency departments and intensive care units in the United States, we randomly assigned critically ill adults (age, ≥18 years) undergoing tracheal intubation to receive preoxygenation with either noninvasive ventilation or an oxygen mask. The primary outcome was hypoxemia during intubation, defined by an oxygen saturation of less than 85% during the interval between induction of anesthesia and 2 minutes after tracheal intubation.

Results: Among the 1301 patients enrolled, hypoxemia occurred in 57 of 624 patients (9.1%) in the noninvasive-ventilation group and in 118 of 637 patients (18.5%) in the oxygen-mask group (difference, -9.4 percentage points; 95% confidence interval [CI], -13.2 to -5.6; P<0.001). Cardiac arrest occurred in 1 patient (0.2%) in the noninvasive-ventilation group and in 7 patients (1.1%) in the oxygen-mask group (difference, -0.9 percentage points; 95% CI, -1.8 to -0.1). Aspiration occurred in 6 patients (0.9%) in the noninvasive-ventilation group and in 9 patients (1.4%) in the oxygen-mask group (difference, -0.4 percentage points; 95% CI, -1.6 to 0.7).

Conclusions: Among critically ill adults undergoing tracheal intubation, preoxygenation with noninvasive ventilation resulted in a lower incidence of hypoxemia during intubation than preoxygenation with an oxygen mask. (Funded by the U.S. Department of Defense; PREOXI ClinicalTrials.gov number, NCT05267652.).

Figure 1.. Screening, Randomization, and Analysis.

A total of 4567 patients underwent screening for eligibility, of whom 3266 were excluded. The most common reasons for exclusion were that the intubation was too urgent to complete trial procedures (20.2% of the patients), the patient was already receiving positive-pressure ventilation (18.4% of the patients), and the patient had vomiting, hematemesis, hemoptysis, or epistaxis (8.5% of the patients). Of the 1301 patients who were enrolled and underwent randomization, 645 were assigned to the noninvasive-ventilation group and 656 were assigned to the oxygen-mask group. All the patients who had undergone randomization were included in the intention-to-treat analysis. Other conditions precluding the use of noninvasive ventilation and other reasons for eligible patients not being enrolled are presented in Table S1 in the Supplementary Appendix.

Figure 2.. Subgroup Analyses of the Risk of Hypoxemia during Intubation.

Shown are the absolute risk differences and 95% confidence intervals for the primary outcome (hypoxemia during intubation, defined by an oxygen saturation of <85% during the interval between induction of anesthesia and 2 minutes after tracheal intubation) in prespecified subgroups. Absolute risk differences in the noninvasive-ventilation group as compared with the oxygen-mask group were calculated with the use of a logistic-regression model with independent variables of trial group, the proposed effect modifier, and the interaction between the trial group and the proposed effect modifier. Absolute risk differences of less than 0 indicate a lower likelihood of hypoxemia with the use of noninvasive ventilation for preoxygenation. The body-mass index is the weight in kilograms divided by the square of the height in meters. Scores on the Acute Physiology and Chronic Health Evaluation (APACHE) II range from 0 to 71, with higher scores indicating a greater severity of illness. Fio₂ denotes fraction of inspired oxygen.