Rationale: Although noninvasive ventilation (NIV) may prevent reintubation in patients at high risk of extubation failure in ICUs, this oxygenation strategy has not been specifically assessed in obese patients. Objectives: We hypothesized that NIV may decrease the risk of reintubation in obese patients compared with high-flow nasal oxygen. Methods:Post hoc analysis of a multicenter randomized controlled trial (not prespecified) comparing NIV alternating with high-flow nasal oxygen versus high-flow nasal oxygen alone after extubation, with the aim of assessing NIV effects according to patient body mass index (BMI). Measurements and Main Results: Among 623 patients at high risk of extubation failure, 206 (33%) were obese (BMI ⩾ 30 kg/m2), 204 (33%) were overweight (25 kg/m2 ⩽ BMI < 30 kg/m2), and 213 (34%) were normal or underweight (BMI < 25 kg/m2). Significant heterogeneity of NIV effects on the rate of reintubation was found according to BMI (Pinteraction = 0.007). Reintubation rates at Day 7 were significantly lower with NIV alternating with high-flow nasal oxygen than with high-flow nasal oxygen alone in obese or overweight patients: 7% (15/204) versus 20% (41/206) (difference, -13% [95% confidence interval, -19 to -6]; P = 0.0002), whereas it did not significantly differ in normal or underweight patients. In-ICU mortality was significantly lower with NIV than with high-flow nasal oxygen alone in obese or overweight patients (2% vs. 9%; difference, -6% [95% confidence interval, -11 to -2]; P = 0.006). Conclusions: Prophylactic NIV alternating with high-flow nasal oxygen immediately after extubation significantly decreased the risk of reintubation and death compared with high-flow nasal oxygen alone in obese or overweight patients at high risk of extubation failure. By contrast, NIV was not effective in normal or underweight patients. Clinical trial registered with www.clinicaltrials.gov (NCT03121482).
Keywords: ICU; airway extubation; high-flow nasal oxygen; noninvasive ventilation; ventilator weaning.