C55-23 Effect Modification by Pulmonary Comorbidity: A Secondary Analysis of the PREOXI Trial

Abstract Rationale The PREOXI trial (NEJM 2024) demonstrated that preoxygenation with noninvasive ventilation (NIV) decreased the incidence of hypoxemia during emergency tracheal intubation compared to oxygen mask in critically ill adults. In patients with acute pulmonary insults (API), including pneumonia, shunting and increased dead space may limit the effectiveness of NIV. In contrast, NIV is well-supported for treatment of acute hypercapnic respiratory failure due to obstructive lung disease (OLD). The effectiveness of NIV as a preoxygenation strategy in patients with API or OLD remains uncertain. Methods We conducted two effect modification (subgroup) analyses of the PREOXI randomized controlled trial evaluating whether (1) the presence of API (defined as pneumonia, aspiration, COVID-19, or ARDS) or (2) chronic OLD (defined as COPD or asthma) modified the effect of preoxygenation with NIV versus oxygen mask. The primary outcome was incidence of hypoxemia during intubation, defined as peripheral oxygen saturation