The importance of the peripheral circulation in critical illnesses

The purpose of this review was to highlight the importance of the peripheral circulation in the regulation of cardiac output and to identify some mechanisms by which this regulation may be disrupted in critical illness. Unfortunately, no easily performed tests are available to measure the mean circulatory filling pressure, venous resistance or the fractions of unstressed and stressed venous volume. However, understanding of the relationship among these factors provides useful insight into the nature of circulatory disturbances and untoward responses to interventions in critically ill patients.