Trendelenburg position: "put to bed" or angled toward use in your unit?

In the mid-19th century, Friedrich Trendelenburg— pioneering German surgeon (1844-1924)— popularized the technique known in the Middle Ages as the “head-down position.” In his surgical text of 1873, Trendelenburg recognized that raising a patient’s hips caused the bulk of abdominal viscera to slide toward the diaphragm, providing a less cluttered operative field for lower abdominal and pelvic procedures. Later in the early-20th century, American physiologist Walter Cannon promoted the Trendelenburg position to displace blood from the lower extremities to enhance venous return in the treatment of hemorrhagic shock. This action was thought to cause an “autotransfusion” to the central circulation, increasing right and left ventricular preloads, stroke volume, and cardiac output (CO)/cardiac index (CI). Despite surgeons questioning the position’s effectiveness in the 1950s because of adverse consequences, use of the Trendelenburg position continued as a mainstay of resuscitation. Although current Advanced Cardiac Life Support and first aid guidelines from the American Red Cross (ARC)/American Heart Association (AHA) state that patients with evidence of shock should be positioned supine, use of the Trendelenburg position may remain a ritualistic practice in response to hypotension. Thus, the following question was prompted: Does use of the Trendelenburg position (head-down or passive leg raising) cause clinically significant increases in blood pressure and CO/CI in hypotensive patients?