Precision and consistency of the passive leg raising maneuver for determining fluid responsiveness with bioreactance non-invasive cardiac output monitoring in critically ill patients and healthy volunteers.

Sahil Chopra,Chris Gasho,Shahab Shahangian,Jordan Thompson,Suman Thapamagar,Avi Cohen,H Bryant Nguyen,Dafne Moretta,Ehab Farag

doi:10.1371/journal.pone.0222956

Sahil Chopra, Chris Gasho + Show 7 more

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https://doi.org/10.1371/journal.pone.0222956

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Abstract

ObjectiveThe passive leg raising (PLR) maneuver has become standard practice in fluid resuscitation. We aim to investigate the precision and consistency of the PLR for determining fluid responsiveness in critically ill patients and healthy volunteers using bioreactance non-invasive cardiac output monitoring (NiCOM™, Cheetah Medical, Inc., Newton Center, Massachusetts, USA).MethodsThis study is prospective, single-center, observational cohort with repeated measures in critically ill patients admitted to the medical intensive care unit and healthy volunteers at a tertiary academic medical center. Three cycles of PLR were performed, each at 20–30 minutes apart. Fluid responsiveness was defined as a change in stroke volume index (ΔSVI) > 10% with each PLR as determined by NiCOM™. Precision was the variability in ΔSVI after the 3 PLR’s, and determined by range, average deviation and standard deviation. Consistency was the same fluid responsiveness determination of “Yes” (ΔSVI > 10%) or “No” (ΔSVI ≤ 10%) for all 3 PLR’s.ResultsSeventy-five patients and 25 volunteers were enrolled. In patients, the precision was range of 17.2±13.3%, average deviation 6.5±4.0% and standard deviation 9.0±5.2%; and for volunteers, 17.4±10.3%, 6.6±3.8% and 9.0±6.7%, respectively. There was no statistical difference in the precision measurements between patients and volunteers. Forty-nine (65.3%) patients vs. twenty-four (96.0%) volunteers had consistent results, p < 0.01. Among those with consistent results, twenty-four (49.0%) patients and 24 (100%) volunteers were fluid responsive.ConclusionsThe precision and consistency of determining ΔSVI with NiCOM™ after PLR may have clinical implication if ΔSVI > 10% is the absolute cutoff to determine fluid responsiveness.

Highlights

Fluid management decisions are a difficult but integral part of daily patient care
There was no statistical difference in the precision measurements between patients and volunteers
We showed that the percent change in stroke volume index (SVI) measured by the NiCOMTM after a passive leg raising (PLR) has a precision of approximately ±9% in both critically ill patients and healthy volunteers

Summary

Introduction

Fluid management decisions are a difficult but integral part of daily patient care. With the growing consensus that extremes of fluid balance may be detrimental, an accurate assessment of a patient’s volume status is paramount [1,2,3,4]. Screening patients who are fluid responsive can appropriately identify those who would likely benefit from fluid resuscitation. Fluid responsiveness as an increase in cardiac output (CO) in response to augmentation of preload is fundamentally based on the classical Frank-Starling curve [5, 6]. If preload augmentation does not increase CO, further intravenous fluids serve no purpose and may potentially be harmful. Clinicians often face the challenge of accurately recognizing when a patient has reached this plateau on the Frank-Starling curve. One maneuver, which has gained acceptance in standard practice to predict fluid responsiveness, without possibly inappropriate fluid administration, is passive leg raising (PLR) [7,8,9]

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