Effect of Noninvasive Ventilation on Tracheal Reintubation Among Patients With Hypoxemic Respiratory Failure Following Abdominal Surgery. A Bayesian post-hoc analysis of the NIVAS trial

Background Clinicians’ decision-making regarding the use of noninvasive ventilation (NIV) after abdominal surgery requires evaluating the probability of clinically meaningful benefit. The Bayesian framework may help caregivers interpret the findings of a randomized controlled trial (NIVAS) assessing curative NIV after abdominal surgery by incorporating their own beliefs and providing better estimates of treatment effects. This study aimed to use a Bayesian framework to estimate posterior probabilities of NIV effect under various prior assumptions, reflecting diverse clinicians’ beliefs. Method A prospectively registered, post-hoc Bayesian reanalysis of the NIVAS multicenter trial was conducted. The study included 293 patients with acute respiratory failure following abdominal surgery who were randomly assigned to receive either conventional oxygen therapy or NIV. Four statistical priors were defined: minimally informative, skeptical, enthusiastic, and pessimistic, reflecting a range of clinical beliefs. The primary outcome was day-7 reintubation. Secondary outcomes included day-30 mortality. Effect sizes were presented as odds ratios (OR) and absolute risk reduction (ARR) with 95% credible intervals (CrI). Results The minimally informative prior resulted in a posterior median OR for day-7 reintubation of 0.59 (95% CrI 0.37 to 0.95) in favor of NIV. Under the pessimistic prior, the posterior median OR was 0.64 (95% CrI 0.40 to 1.00). The posterior probability of NIV being superior to oxygen therapy varied from 96 to 99% when considering various priors from pessimistic to enthusiastic. The probability of benefit beyond an ARR ≥ 5% ranged from 77 to 93%. Regarding day-30 mortality, the posterior median OR was 0.63 (95% CrI 0.32 to 1.31) under minimally informative prior and 0.79 (95% CrI 0.48 to 1.29) under the skeptical prior. The probability of NIV superiority ranged from 82 to 90%. Conclusion This pre-registered Bayesian analysis indicates that NIV consistently reduces day-7 reintubation, with a high probability of achieving a clinically meaningful effect, even under pessimistic prior beliefs. These results provide compelling evidence for its broad use to treat respiratory failure after abdominal surgery. There was a high probability of mortality reduction with NIV, though the effect magnitude was imprecise.