Physiological effects of acute hypoxaemia and hyperoxaemia
| Hypoxaemia | Hyperoxaemia | |||
|---|---|---|---|---|
| Effects | Risks | Effects | Risks | |
| Respiratory system | Increased ventilation Pulmonary vasoconstriction | Pulmonary hypertension | Decreased ventilation (minimal) | Worsened ventilation/perfusion matching Absorption atelectasis |
| Cardiovascular system | Coronary vasodilation Decreased systemic vascular resistance (transient) Increased cardiac output Tachycardia | Myocardial Ischaemia/infarction Ischaemia/infarction of other critically perfused organs Hypotension Arrhythmias | Myocardial ischaemia (in context of decreased haematocrit) Reduced cardiac output Reduced coronary blood flow Increased blood pressure Increased peripheral resistance | |
| Metabolic system | Increased 2,3-DPG Increased CO2 carriage (Haldane effect) | Lactic acidosis | Decreased 2,3-DPG Decreased CO2 carriage (Haldane effect) | Increased reactive oxygen species |
| Neurological system | Increased cerebral blood flow due to vasodilation | Confusion Delirium Coma | Decreased cerebral blood flow | |
| Renal system | Renin–angiotensin axis activation Increased erythropoietin production | Acute tubular necrosis | Reduced renal blood flow | |
2,3-DFG, 2,3-diphosphoglycerate.