Hyperoxia reversibly alters oxygen consumption and metabolism.

Aim: Ventilation with pure oxygen (hyperoxic ventilation: HV) is thought to decrease whole body oxygen consumption (VO(2)). However, the validity and impact of this phenomenon remain ambiguous; until now, under hyperoxic conditions, VO(2) has only been determined by the reverse Fick principle, a method with inherent methodological problems. The goal of this study was to determine changes of VO(2), carbon dioxide production (VCO(2)), and the respiratory quotient (RQ) during normoxic and hyperoxic ventilation, using a metabolic monitor.

Effects of alterations of inspiratory oxygen fractions on heart rate variability.

Background: Changes in heart rate variability (HRV) during anaesthesia depend on multiple influences such as hypnosis, analgesia, surgical stress, and interacting drugs. Several recent studies have aimed to establish HRV-based monitoring tools to measure perioperative stress or anaesthetic depth. Although hyperoxic ventilation (HV) is known to alter autonomic cardiovascular regulation, there have been no studies investigating its influence on time- and frequency-domain analysis during general anaesthesia.