1/7 #PREPAREII showed that a 500-ml fluid bolus does not prevent cardiovascular collapse during tracheal intubation in the ICU. I love efficient study designs - this trial had two features that in my opinion are worth replicating in future #criticalcare #RCTs (a thread 🧵): 2/7 Sample size: the authors calculated that 750 patients would be needed to detect a MCID with an 80% power. After a blinded interim analysis it became clear that the event rate is lower than expected. Smart study design feature no.1️⃣: adaptive sample size re-estimation.