| Class | Vital ingredient of multicellular life |
|---|---|
| Chemistry |
Diatomic gas |
| Routes of administration |
Inhaled; also as intravenous or intra-arterial infusion of well-oxygenated blood (i.e. ECMO), and can be given externally (as in hyperbaric oxygen therapy) |
| Absorption |
Absorbs rapidly into the pulmonary circulation via the lungs (250ml/min with 21% FiO2, at rest) |
| Solubility |
Poor solubility in water |
| Distribution |
Widely distributed- total body oxygen content is 64% by weight. Highly protein-bound (to haemoglobin) |
| Metabolism |
Metabolised in all tissues (mainly brain, heart and skeletal muscle) |
| Elimination |
Rapidly eliminated by metabolism into CO2 and water |
| Time course of action |
Minutes |
| Target receptor |
Cytochrome c mitochondrial enzymes |
| Mechanism of action |
Increases ATP by acting a substrate for aerobic metabolism of glucose |
| Clinical effects |
Drying of mucous membranes and inspissation of secretions Inflammatory tracheobronchitis Decreased central respiratory drive (minimally) Hypecapnoea in "CO2 retainers" mainly by virtue of V/Q mismatch and Haldane effect \Absorption atelectasis Increased left-to-right shunting in ASDs Increased peripheral vascular resistance Cerebral and coronary vasoconstriction Euphoria Retrolental fibroplasia of the newborn Decreased erythropoiesis |
| Literature reference |
Haim Bitterman's 2009 article, "Bench-to-bedside review: oxygen as a drug" |
| CICM details of understanding | Level 1 |
| Mentioned around Deranged Physiology |
Pharmacology of oxygen (a monograph). Also, vaguely related, Physiological effects of hyperoxia and Causes and physiological effects of hypoxemia; possibly also The oxygen cascade? |
| Related SAQs |
Question 1 from the first paper of 2011 Question 6 from the first paper of 2009 Question 14 from the first paper of 2023 |