Respiratory variations in aortic blood flow predict fluid responsiveness in ventilated children
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To investigate whether respiratory variations in aortic blood flow velocity (ΔVpeak ao), systolic arterial pressure (ΔPS) and pulse pressure (ΔPP) could accurately predict fluid responsiveness in ventilated children.
Design and setting
Prospective study in a 18-bed pediatric intensive care unit.
Twenty-six children [median age 28.5 (16–44) months] with preserved left ventricular (LV) function.
Standardized volume expansion (VE).
Measurements and main results
Analysis of aortic blood flow by transthoracic pulsed-Doppler allowed LV stroke volume measurement and on-line ΔVpeak ao calculation. The VE-induced increase in LV stroke volume was > 15% in 18 patients (responders) and < 15% in 8 (non-responders). Before VE, the ΔVpeak ao in responders was higher than that in non-responders [19% (12.1–26.3) vs. 9% (7.3–11.8), p = 0.001], whereas ΔPP and ΔPS did not significantly differ between groups. The prediction of fluid responsiveness was higher with ΔVpeak ao [ROC curve area 0.85 (95% IC 0.99–1.8), p = 0.001] than with ΔPS (0.64) or ΔPP (0.59). The best cut-off for ΔVpeak ao was 12%, with sensitivity, specificity, and positive and negative predictive values of 81.2%, 85.7%, 93% and 66.6%, respectively. A positive linear correlation was found between baseline ΔVpeak ao and VE-induced gain in stroke volume (rho = 0.68, p = 0.001).
While respiratory variations in aortic blood flow velocity measured by pulsed Doppler before VE accurately predict the effects of VE, ΔPS and ΔPP are of little value in ventilated children.
KeywordsAortic blood flow velocity Cardiac output Septic shock Mechanical ventilation Fluid responsiveness Children
central venous pressure
diastolic arterial pressure, ΔPS respiratory changes in systolic arterial pressure
respiratory changes in arterial pulse pressure
ao respiratory changes in aortic peak velocity
left ventricular ejection time index
mean arterial pressure
norepinephrine, NR non-responders to VE
responders to VE
systolic arterial pressure
pulmonary artery occlusion pressure
aortic velocity time integral