Purpose: This study aimed to investigate the effects of inspired oxygen fraction (FiO2) and positive end-expiratory pressure (PEEP) on gas exchange in mechanically ventilated patients with COVID-19.

Introduction Hypoxic challenge test consisting of breathing 15% FiO2 for 20 min with blood gas measurements is recommended by BTS guidelines for the assessment of the requirement for in-flight oxygen.

Background: A major contributor to unfavorable outcome after traumatic brain injury (TBI) is secondary brain injury. Low brain tissue oxygen tension (PbtO2) has shown to be an independent predictor of ...