The need for peri-operative supplemental oxygen

Molecular oxygen is a colourless and odourless gas which is essential to life. It accounts for 21% of the atmospheric air. Apart from its central role in oxidative phosphorylation to produce biological energy in the form of adenosine triphosphate (ATP), molecular oxygen is used as substrate by two other enzyme systems for the killing of bacteria in the phagocytes and for collagen synthesis by the fibroblast during wound healing. In the immediate post operative period atmospheric oxygen might become inadequate for a number of reasons including hypoventilation due to central pharmacological depression, diffusion hypoxia and increased metabolic rate due to shivering (the so called halothane shakes).