ABSTRACT
High PIO2 has several physiological eects on the body. Although increased PIO2 has no direct eect on ventilation, there is a decrease in alveolar and arterial carbon dioxide (CO2) buering tension caused by the reduction in CO2-carrying capacity of haemoglobin. Other physiological responses to
high oxygen include vagally mediated bradycardia and vasoconstriction of intracranial and peripheral vessels. ere is a small rate-dependent fall in cardiac output.
