Comprehensive review: is it better to use the Trendelenburg position or passive leg raising for the initial treatment of hypovolemia?

Hypovolemia is a common clinical problem. The Trendelenburg position and passive leg raising (PLR) are routinely used in the initial treatment while awaiting fluid resuscitation. In this meta-analysis, we evaluated the hemodynamic effects of PLR and Trendelenburg positioning to determine which position had the most optimal effect on cardiac output (CO). Databases were searched for prospective studies published between 1960 and 2010 in normovolemic or hypovolemic humans; these studies had to investigate the hemodynamic effects within 10 minutes of a postural change from supine. Twenty-one studies were included for PLR (n=431) and 13 studies for Trendelenburg position (n=246). Trendelenburg position increased mean arterial pressure (MAP). Cardiac output increased 9%, or 0.35 L/min, at one minute of head-down tilt. Between 2 and 10 minutes, this increase in CO decreased to 4%, or 0.14 L/min, from baseline. Cardiac output increased at one minute of leg elevation by 6%, or 0.19 L/min. The effect persisted after this period by 6%, or 0.17 L/min. Both Trendelenburg and PLR significantly increased CO, but only PLR seemed to sustain this effect after one minute. Although the Trendelenberg position is a common maneuver for nurses and doctors, PLR may be the better intervention in the initial treatment of hypovolemia.