Discussion
cerebral TOI, desaturation, hypoxia, apnea, non-obese
HYPOXIA, OBESE
This study assessed the effect of OThe benefits of COObese patients represent a population particularly vulnerable to hypoxia as they have a reduced oxygen reserve due to a lower FRC. Indeed, even after pre-oxygenation, obese patients present with a clinically relevant desaturation to 90% in less than three minutes, which is much faster compared to non-obese patients [A strength of our study was the crossover study design, which increases the precision of the treatment effect measurement and minimizes confounding, as each patient acts as their control.Our study, however, has some limitations. The primary outcome, the length of the apnea phase until TOI decreased by a relative 20% from baseline, could not be reached due to safety reasons. Changing a primary endpoint after the start of a clinical trial is only justifiable if the reasons for doing so are based on new information unrelated to the study conducted, for example, from another independent study [For this study, we defined our primary endpoint as a relative 20% cerebral TOI reduction from baseline. A larger decrease has a negative predictive value in carotid surgery [The safety abortion criterion was chosen so that a clinically relevant level of hypoxia was reached while ensuring the patient’s safety, based on previous data. While data on anesthetized patients are scarce, hypoxia studies in awake probands exposed to SaO