Research

Brachial artery peak velocity variation to predict fluid responsiveness in mechanically ventilated patients

Manuel Ignacio Monge García , Anselmo Gil Cano and Juan Carlos Díaz Monrové

Servicio de Cuidados Críticos y Urgencias, Unidad de Investigación Experimental, Hospital del SAS Jerez, C/Circunvalación s/n, 11407, Jerez de la Frontera, Spain

author email corresponding author email

Critical Care 2009, 13:R142doi:10.1186/cc8027

Published:	3 September 2009

See related commentary by Schmidt http://ccforum.com/content/13/5/195

Abstract

Introduction

Although several parameters have been proposed to predict the hemodynamic response to fluid expansion in critically ill patients, most of them are invasive or require the use of special monitoring devices. The aim of this study is to determine whether noninvasive evaluation of respiratory variation of brachial artery peak velocity flow measured using Doppler ultrasound could predict fluid responsiveness in mechanically ventilated patients.

Methods

We conducted a prospective clinical research in a 17-bed multidisciplinary ICU and included 38 mechanically ventilated patients for whom fluid administration was planned due to the presence of acute circulatory failure. Volume expansion (VE) was performed with 500 mL of a synthetic colloid. Patients were classified as responders if stroke volume index (SVi) increased ≥ 15% after VE. The respiratory variation in Vpeak_brach (ΔVpeak_brach) was calculated as the difference between maximum and minimum values of Vpeak_brach over a single respiratory cycle, divided by the mean of the two values and expressed as a percentage. Radial arterial pressure variation (ΔPP_rad) and stroke volume variation measured using the FloTrac/Vigileo system (ΔSV_Vigileo), were also calculated.

Results

VE increased SVi by ≥ 15% in 19 patients (responders). At baseline, ΔVpeak_brach, ΔPP_rad and ΔSV_Vigileo were significantly higher in responder than nonresponder patients [14 vs 8%; 18 vs. 5%; 13 vs 8%; P < 0.0001, respectively). A ΔVpeak_brach value >10% predicted fluid responsiveness with a sensitivity of 74% and a specificity of 95%. A ΔPP_rad value >10% and a ΔSV_Vigileo >11% predicted volume responsiveness with a sensitivity of 95% and 79%, and a specificity of 95% and 89%, respectively.

Conclusions

Respiratory variations in brachial artery peak velocity could be a feasible tool for the noninvasive assessment of fluid responsiveness in patients with mechanical ventilatory support and acute circulatory failure.

Trial Registration

ClinicalTrials.gov ID: NCT00890071