North Trent Critical Care Network

Written by Critical Care The human foetus develops in a profoundly hypoxic environment. Thus the foundations of our physiology are built in the most hypoxic conditions that we are likely to ever experience; within the womb. This magnitude of exposure to hypoxia in utero is rarely experienced in adult life, with few exceptions including severe pathophysiology in critical illness, and environmental hypobaric hypoxia at high altitude. Indeed, the lowest recorded levels of arterial oxygen in adult humans are similar to those of a foetus and were recorded just below the highest attainable elevation on the Earth's surface; the summit of Mount Everest. We propose that the hypoxic intra-uterine environment exerts a profound effect on human tolerance to hypoxia. Cellular mechanisms that facilitate foetal well being may be amenable to manipulation in adults to promote survival advantage in severe hypoxaemic stress. Many of these mechanisms act to modify the process of oxygen consumption rather than oxygen delivery in order to maintain adequate tissue oxygenation. The successful activation of such processes may provide a new chapter in the clinical management of hypoxaemia. Thus, strategies employed to endure the relative hypoxia in utero may provide insights for the management of severe hypoxaemia in adult life and ventures to high altitude the means by which to investigate them.

Authors: Daniel Martin

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