Bayesian Analysis of the Pragmatic Airway Resuscitation Trial.

STUDY OBJECTIVE: Intubation and laryngeal tube insertion are common airway management strategies in out-of-hospital cardiac arrest. Bayesian analysis offers an alternate statistical approach to assess the results of a trial. We use Bayesian analysis to compare the effectiveness of initial laryngeal tube versus initial intubation strategies on outcomes after out-of-hospital cardiac arrest in the Pragmatic Airway Resuscitation Trial.

METHODS: We performed a post hoc Bayesian analysis of the Pragmatic Airway Resuscitation Trial. We defined prior distributions representing neutral or skeptical estimates of laryngeal tube benefit. Using Bayesian log binomial models, we fit models for 72-hour survival, hospital survival, and hospital survival with favorable neurologic status. We estimated the posterior probability (the probability of observing an effect difference between treatment groups) of the benefit of laryngeal tube over intubation on out-of-hospital cardiac arrest outcomes.

RESULTS: The parent trial enrolled 3,004 patients (1,505 laryngeal tube, 1,499 intubation). Under a neutral prior distribution (relative risk 1.0), laryngeal tube was better than intubation (72-hour survival risk difference 1.8% [95% credible interval {CrI} -0.9% to 4.5%], posterior probability 91%; hospital survival 1.4% [95% CrI -0.4% to 3.4%], posterior probability 93%; and hospital survival with favorable neurologic status 0.7% [95% CrI -0.5% to 2.1%], posterior probability 86%). Under a skeptical prior distribution (relative risk 0.83 to 0.92), laryngeal tube was also better than intubation (72-hour survival risk difference 1.7% [95% CrI -0.9% to 4.3%], posterior probability 89%; hospital survival 1.3% [95% CrI -0.5% to 3.3%], posterior probability 91%; and hospital survival with favorable neurologic status 0.6% [95% CrI -0.5% to 2.0%], posterior probability 82%).

CONCLUSION: Under various prior assumptions, post hoc Bayesian analysis of the Pragmatic Airway Resuscitation Trial confirmed better out-of-hospital cardiac arrest outcomes with a strategy of initial laryngeal tube than initial intubation.