Predicting fluid responsiveness in mechanically ventilated children under general anaesthesia using dynamic parameters and transthoracic echocardiography.

Pereira de Souza Neto, E; Grousson, S; Duflo, F; Ducreux, C; Joly, H; Convert, J; Mottolese, C; Dailler, F; Cannesson, M

BACKGROUND Dynamic variables are accurate predictors of fluid responsiveness in adults undergoing mechanical ventilation. They can be determined using respiratory variation in aortic flow peak velocity (â–µVpeak), arterial pulse pressure [â–µPP and pulse pressure variation (PPV)], or plethysmographic waveform amplitude [â–µPOP and pleth variability index (PVI)]. These indices have not been validated in children. We studied the ability of these variables to predict fluid responsiveness in mechanically ventilated children. METHODS All results are expressed as median [median absolute deviation (MAD)]. Thirty mechanically ventilated children were studied after undergoing general anaesthesia. Mechanical ventilation was maintained with a tidal volume of 10 ml kg(-1) of body weight. â–µPP, PPV, â–µPOP, PVI, â–µVpeak, and aortic velocity-time integral were recorded before and after volume expansion (VE). Patients were considered to be responders to VE when the aortic velocity-time integral increased more than 15% after VE. RESULTS VE induced significant changes in â–µPP [13 (MAD 4) to 9 (5)%], PPV [15 (5) to 9 (5)%], â–µPOP [15 (10) to 10 (6)%], PVI [13 (6) to 8 (5)%], and â–µVpeak [16 (9) to 8 (3)%] (P<0.05 for all). Differences in â–µPP, â–µPOP, PPV, and PVI did not reach statistical significance. Only â–µVpeak was significantly different between responders (R) and non-responders (NR) to VE [22 (3) vs 7 (1)%, respectively; P<0.001]. The threshold â–µVpeak value of 10% allowed discrimination between R and NR. CONCLUSIONS In this study, â–µVpeak was the most appropriate variable to predict fluid responsiveness.