Uncalibrated Stroke Volume Variations Are Able to Predict the Hemodynamic Effects of Positive End-Expiratory Pressure in Patients with Acute Lung Injury or Acute Respiratory Distress Syndrome after Liver Transplantation

Background: Positive end-expiratory pressure (PEEP) may reduce cardiac output and total hepatic blood flow after liver transplantation. Pulse pressure variation is useful in predicting the PEEP-induced decrease in cardiac output. The aim of the study was to examine the relationships between stroke volume variations (SVV) obtained with the Vigileo monitor (Edwards Lifesciences, Irvine, CA), and the hemodynamic effects of PEEP. Methods: Over 2 yr, patients presenting an acute lung injury or an acute respiratory distress syndrome in the 72 h after liver transplantation were prospectively enrolled. Patients were monitored with a pulmonary artery catheter (stroke volume) and with the Vigileo system (stroke volume and SVV). Measurements were performed in duplicate, first during zero end-expiratory pressure and then 10 min after the addition of 10 cm H2O PEEP. Results: Twenty-six patients were included. Six patients were excluded from analysis. On PEEP, SVV and pulse pressure variation increased significantly and stroke volume decreased significantly. PEEP-induced changes in stroke volume measured by pulmonary artery catheter were significantly correlated with SVV (r 2 0.69; P 15% was predicted by an SVV > 7% (sensitivity 100%, specificity 80%) and by a pulse pressure variation > 8% (sensitivity 80%, specificity 100%). PEEP-induced changes in stroke volume measured by pulmonary artery catheter and Vigileo device were correlated (r 2 0.51, P < 0.005). Conclusions: SVV obtained with Vigileo monitor is useful to predict decrease in stroke volume induced by PEEP. Moreover, this device is able to track changes in stroke volume induced by PEEP.