Passive leg raising (PLR) is a great ‘free reversible fluid challenge’ to see if a shocked or hypotensive patient is likely to respond to volume therapy. A new study assesses its applicability in children.
PLR predicted fluid responders with 85% specificity but a lack of response did not rule out fluid responsiveness. Also, the effect of the PLR on cardiac index measured by echocardiography was the only way of predicting response – there was no relation to the more easily monitored effects of PLR on systolic blood pressure or heart rate.
Want to learn how to measure cardiac output using ultrasound? Mike Mallin from the Emergency Ultrasound Podcast shows you how here
OBJECTIVE: Fluid challenge is often used to predict fluid responsiveness in critically ill patients. Inappropriate fluid expansion can lead to some unwanted side effects; therefore, we need a noninvasive predictive parameter to assess fluid responsiveness. We want to assess the hemodynamic parameter changes after passive leg raising, which can mimic fluid expansion, to predict fluid responsiveness in pediatric intensive care unit patients and to get a cutoff value of cardiac index in predicting fluid responsiveness in pediatric patients.
DESIGN: Nonrandomized experimental study.
SETTING: Tertiary academic pediatric intensive care.
PATIENTS: Children admitted to pediatric intensive care.
INTERVENTION: Hemodynamic parameters were assessed at baseline, after passive leg raising, at second baseline, and after volume expansion (10 mL/kg normal saline infusion over 15 mins).
MEASUREMENTS AND MAIN RESULTS: We measured the heart rate, systolic blood pressure, and stroke volume and cardiac index using Doppler echocardiography. The hemodynamic parameter changes induced by passive leg raising were monitored. Among 40 patients included in the study, 20 patients had a cardiac index increase of ≥10% after volume expansion (responders). Changes in heart rate, systolic blood pressure, and stroke volume after passive leg raising did not significantly relate to the response to volume expansion. There was significant relation between changes in cardiac index to predict fluid responsiveness (p = .012, r = .22, 95% confidence interval 1.529 to 31.37). A cardiac index increase by ≥10% induced by passive leg raising predicted preload-dependent status with sensitivity of 55% and specificity of 85% (area under the curve 0.71 ± 0.084, 95% confidence interval 0.546-0.874).
CONCLUSION: The concomitant measurements in cardiac index changes after the passive leg raising maneuver can be helpful in predicting who might have an increase in cardiac index with subsequent fluid resuscitation.
The role of passive leg raising to predict fluid responsiveness in pediatric intensive care unit patients.
Pediatric Critical Care Medicine. 13(3):e155-e160, May 2012