Q: Passive Leg Raise (PLR) testing gives more reliable result when initial hemodynamic data {Cardiac Output (CO) or Pulse-Pressure-Variation (PPV) } is obtained by putting patient at 45 degrees, and obtain hemodynamic data again by

A) Lowering the patient's head to the horizontal position and raise the legs at 45 degrees for about 60-90 seconds

B) Lowering the patient's head to the horizontal position and raise the legs at 90 degrees for about 60-90 seconds

C) Lowering the patient's head to the horizontal position and raise the legs at 45 degrees for about 10-15 seconds.

D) Keep the patient's body to 45 degrees and lower the legs at 90 degrees for about 60-90 seconds

E) PLR testing should be preceded by 500 cc Albumin bolus over 15 minutes, otherwise data is not reliable

Answer: A

PLR test, though easy to perform but is a complex hemodynamic maneuver. It requires proper testing. Answer A is correct as maximal effect occurs at 30-90 seconds. If performed incorrectly, it may lead to erroneous conclusion and may harm the patient. Also, it should be read in conjunction with other maneuver like Pulmonary artery catheter (PAC) data, PPV on arterial line or bedside point of care echo-cardiogram. Also, it should be understand that PLR is more about predicting patient responsiveness to fluid, rather total volume status or ventricular function, though they may important roles. Answer E is wrong as PLR better be performed before IVF bolus.

By definition, a 10 percent increase in CO or decrease in PPV predicts volume responsiveness.

Références and further reading: 

1.  Préau S, Saulnier F, Dewavrin F, Durocher A, Chagnon JL. Passive leg raising is predictive of fluid responsiveness in spontaneously breathing patients with severe sepsis or acute pancreatitis. Crit Care Med. 2010 Mar;38(3):819-25

2. Marik PE, Monnet X, Teboul JL. Hemodynamic parameters to guide fluid therapy. Ann Intensive Care 2011; 1:1. 

3. Mandeville JC, Colebourn CL. Can transthoracic echocardiography be used to predict fluid responsiveness in the critically ill patient? A systematic review. Crit Care Res Pract 2012; 2012:513480. 

4. Cherpanath TG, Hirsch A, Geerts BF, et al. Predicting Fluid Responsiveness by Passive Leg Raising: A Systematic Review and Meta-Analysis of 23 Clinical Trials. Crit Care Med 2016; 44:981. 

5. Bentzer P, Griesdale DE, Boyd J, et al. Will This Hemodynamically Unstable Patient Respond to a Bolus of Intravenous Fluids? JAMA 2016; 316:1298.