Perioperative hypoxia. The clinical spectrum and current oxygen monitoring methodology

When searching for the source of hypoxia, the anesthesiologist and intensivist one served best by treating the patient in an organized approach--beginning with the environmental and pulmonary sources, searching for anemic and circulatory sources, and finally ruling out the less common histocytic causes. When treating hypoxia, the first maneuver should be to administer oxygen, ensure airway, ventilation, and circulation (the ABCs of basic life support). Further monitoring is addressed at global assessments and specific organ systems (especially in high-risk patients or during high-risk procedures). The ability to directly measure the oxygenation, blood flow, and function in each individual organ of the body is not yet available. Efforts are advancing in the ability to measure the function of important tissue beds, such as the brain and splanchnic circulation. In this regard, Table 5 provides a summary of the spectrum of monitoring technology available for various organs.