부산대학교 도서관

Objective To evaluate the ability of aPP/aP [pulse pressure variations (aPP) adjusted by alveolar pressure variations (aP = Pplat-PEEPtot)] in predicting fluid responsiveness, to compare its accuracy to that of aPP used alone and to evaluate the influence of tidal volume (Vt) on these two indices. Design Prospective study. Setting A 22-bed general intensive care unit (ICU). Patients Eighty-four surgical or medical ventilated patients requiring fluid challenge. Intervention A 6 ml/kg colloid fluid challenge in 30 min. Measurements and results Hemodynamic measurements taken before and after fluid challenge. Patients separated into responders and nonresponders according to a 15% increase in their cardiac output. Thirty-nine patients found to be responders and 45 nonresponders. aPP/aP and aPP were both higher in responders than in nonresponders. aPP/aP was a better predictor of fluid responsiveness than aPP, especially for patients ventilated with Vt aY= 8 ml/kg [area under the curve (AUC) 0.88 (0.77--0.98) versus 0.75 (0.60--0.89), P < 0.01)]. In this population aPP/aP higher than 0.9 predicted fluid response with positive predictive value of 87% and negative predictive value of 78%. Overall aPP and aPP/aP reliability was poor for patients ventilated with Vt < 8 ml/kg [AUC 0.63 (0.45--0.81) and 0.72 (0.55--0.88), respectively]. Conclusion In this mixed ICU population aPP adjusted by aP is a simple index which outperforms aPP for patients ventilated with Vt aY= 8 ml/kg. However, correcting aPP by aP still fails to predict fluid response reliably in patients ventilated with low tidal volume.