Background and Aims Prediction of fluid response is of paramount importance when managing shock. The aim of the present study was to test the hypothesis that pre-infusion values of several hemodynamic and perfusion parameters could help to predict fluid responsiveness in an infant animal model of hemorrhagic shock.
Methods Prospective, observational study in 20 two month-old piglets (9.9±2kg). Following mechanical ventilation, hypovolemia was induced by controlled 30 ml/kg bleed. After 30′ pigs received Normal Saline (NS) 30 ml/kg, n=10 or Albumin 5% plus Hypertonic 3% Saline (AHS) 15 ml/kg, n=10, over 30 min. Hemodynamic parameters determined by femoral arterial thermodilution calibrated pulse contour analysis, central venous saturation (SvO2), and intramucosal gastric pH (pHi) were recorded before and after fluid load. Non-parametric correlations between pre-infusion parameters and post-infusion changes with cardiac index increase (ΔCI) were analyzed.
Results CI (median; IQR) increased from 2.1 (1.7–2.7) to 4.1 (3.6–4.6) L/min/m2. There were no correlations between ΔCI and pre-infusion parameters or post-infusion changes in most parameters. Only pre-infusion stroke volume index (SVI) and global end diastolic volume index (GEDVI) showed strong negative correlation (SVI r: –0.61, p: 0.009; GEDVI r: –0.75, p: 0.001). ΔCI showed also strong correlation with SVI increase (r: 0.89, p: 0.000) and GEDVI increase (r: 0.88, p: 0.000).
Conclusion Pre-infusion SVI and GEDVI were predictor parameters of fluid response in this model of hemorrhagic shock. Other parameters previously proposed as predictors of fluid response as SvO2, PPV and SVV were not able to predict changes in cardiac index.