Prediction of Fluid Responsiveness Using Pressure Record Analytical Method in Infants After Cardiopulmonary Bypass

Introduction: Volume expansion therapy is considered the first-line treatment in infants after cardiopulmonary bypass (CPB), but excessive volume is harmful. Pulse pressure variance (PPV) is derived from analysis of the arterial waveform and based on lung-heart interaction during mechanical ventilation. It has been used to guide volume treatment mostly in closed chest patients. The degree of lung compression might be different in different body position, potentially affecting heart-lung interaction. Hypothesis: PPV by pressure record analytical method (PRAM) could predict fluid responsiveness in infants after CPB in open chest conditions with supine or left lateral decubitus. Methods: Infants during CPB for ventricular septal defect repair with supine decubitus (n=24) and left lateral decubitus (n=29) were enrolled. After CPB, mechanical ventilation was set with tidal volume 10 ml/kg. 5% albumin or blood plasma routinely was given (150 ml/min) over 15 minutes. PPV was recorded using PRAM along with heart rate (HR), dicrotic pressure (DicP), stroke volume index (SVI), cardiac index (CI) and cardiac cycle efficiency (CCE) before and after loading changes. Patients were considered as responders to fluid loading when CI increased ≥15%. Results: In children with supine decubitus, 12 were responders and 14 non-responders. PPV in responders was higher than that in non-responders (25.7±6.4% vs. 16.6±5.0%, P<0.05). Area under the curve (AUC) was 0.85 and cutoff value 19% with a sensitivity of 92% and a specificity of 64%. In children with left lateral decubitus, 16 were responders) and 13 non-responders. PPV in responders were higher than that in non-responders (25.0±6.8% vs. 18.2±5.3%, P<0.05), AUC was 0.83 and cutoff value 18% with a sensitivity of 88% and a specificity of 70%. Responders in both groups had increased DicP, SVI, CI and CCE after fluid loading (P<0.05). Conclusions: PPV by PRAM can predict fluid responsiveness in infants immediately after CPB in open chest conditions both with supine and left lateral decubitus.