IN 1890 Trendelenburg described the position of head-down body tilt to improve surgical exposure of pelvic organs. During World War I, this position was suggested for the treatment of shock assuming that it would increase blood pressure, improve cerebral blood flow, and increase venous return from the legs. Despite lack of objective data supporting its efficacy, the Trendelenburg position has become a standard therapeutic maneuver in shock. Recently, evidence has been obtained that blood pressure is actually slightly decreased in the Trendelenburg position secondary to baroreceptor activity.1In addition, there is evidence that carotid blood flow in animals is not increased in this position.2Impaired pulmonary function results in man in the Trendelenburg position.3-4 However, since the blood pooled in the lower extremities may be as much as 1000 cc,5the advantage of returning this pool to the central circulation warrants consideration. In an attempt to