Effect of various lithotomy positions on lower-extremity blood pressure

Background: Compartment syndrome of a lower extremity from hypoperfusion is a rare but potentially devastating complication of the lithotomy position during surgery. The aim of this study is to determine the effects of variou s lithotomy positions on lower-extremity blood pressures. Methods: Blood pressure in eight young, healthy people was studied for 10 l ithotomy positions. Blood pressure measurements were taken in both the uppe r arm (brachial artery) and the lower extremity (dorsalis pedis). The heart -to-ankle height gradient in each position was measured, and a predicted lo wer-extremity systolic pressure was calculated. The measured and predicted lower-extremity systolic blood pressures were compared with repeated measur es analysis of variance, Results: As a group, the mean systolic blood pressures in the lower extremi ties correlated closely with the predicted values. However, the difference between measured and predicted pressures varied among the 10 positions (P < 0.05). Conclusions: Although lower-extremity systolic blood pressures In the young , healthy volunteers correlated with predicted values, there was an additio nal reduction in pressure associated with the Lithotomy position. This surp rising finding suggests that a lengthy procedure necessitating the use of a lithotomy position for only a portion should be planned so the remainder o f the procedure can take place before establishing the position or so the p osition can be changed to an alternative position when it Is no longer need ed.