PAULA ALONSO QUINTELA (Spain)
Complejo Asistencial Universitario de León Neonatal Intensive Care UnitAuthor Of 1 Presentation
RESPIRATORY VARIATION IN AORTIC BLOOD FLOW PEAK VELOCITY AND RESPONSE TO A FLUID CHALLENGE IN VENTILATED NEONATES
Abstract
Background and Aims
Assessment of preload responsiveness by dynamic indexes has been recommended to guide fluid therapy in the critical care setting but this strategy has never been tested in neonates. Our aim was to assess respiratory variation in aortic blood flow peak velocity (ΔVpeak) as a predictor of preload responsiveness in mechanically ventilated and hemodynamically unstable neonates.
Methods
Prospective observational diagnostic accuracy study. Consecutive mechanically ventilated and hemodynamically unstable neonates who received a first fluid bolus (10 ml/kg of normal saline over 20 minutes) for suspected hypovolemia were eligible. ΔVpeak and superior vena cava flow (SVCf) were measured at baseline (T0), immediately upon completion of the fluid infusion (T1) and at one hour after fluid administration (T2). Preload responsiveness was defined as an increase in SVCf >10% at T1 (ΔSVCfT1-T0).
Results
Forty-six infants with a median (IQR) gestational age of 30.5 (28-36) weeks were included. Twenty-nine (63%) infants were fluid responders (F-R), and 17 (37%) were fluid non-responders (F-nR). FR had a higher baseline (T0) ΔVpeak than F-NR [9% (8.2-10.8) vs 5.5% (3.7-6.6); p<0.001]. Baseline ΔVpeak was correlated with ΔSVCfT1-T0 (rho=0.841, p<0.001). The area under the ROC curve of ΔVpeak to predict fluid responsiveness was 0.912 (95% CI: 0.82-1). An ΔVpeak cut-off point of 7.8% provided a 90% (95% CI: 71-97) sensitivity, 88% (95% CI: 62-98) specificity, 7.6 (95% CI: 2-28) positive likelihood ratio and 0.11 (95%CI: 0.03-0.34) negative likelihood ratio to predict fluid responsiveness.
Conclusions
ΔVpeak accurately predicted preload responsiveness in hemodynamically unstable neonates under mechanical ventilation.