Noninvasive assessment of cardiac output.

Improved outcome from shock depends on early detection and correction of circulatory abnormalities. Global cardiac output and oxygen delivery must be adequate and distributed appropriately to meet metabolic demands to prevent the development of multiple organ system dysfunction, prolonged morbidity, and death. Circulatory assessment using standard monitors gives incomplete and sometimes misleading information. This article focuses on the available and emerging technologies that emphasize assessment of blood flow and regional tissue oxygenation.