Comparison between respiratory changes in the inferior vena cava diameter and pulse pressure variation to predict fluid responsiveness in postoperative patients

Abstract

Purpose: The objective of our study was to assess the reliability of the distensibility index of the inferior vena cava (dIVC) as a predictor of fluid responsiveness in postoperative, mechanically ventilated patients and compare its accuracy with that of the pulse pressure variation (PPV) measurement. Materials and methods: We included postoperative mechanically ventilated and sedated patients who underwent volume expansion with 500 mL of crystalloids over 15 minutes. A response to fluid infusion was defined as a 15% increase in the left ventricular outflow tract velocity time integral according to transthoracic echocardiography. The inferior vena cava diameters were recorded by a subcostal view using the M-mode and the PPV by automatic calculation. The receiver operating characteristic (ROC) curves were generated for the baseline dIVC and PPV. Results: Twenty patients were included. The area under the ROC curve for dIVC was 0.84 (95% confidence interval, 0.63-1.0), and the best cutoff value was 16% (sensitivity, 67%

specificity, 100%). The area under the ROC curve for PPV was 0.92 (95% confidence interval, 0.76-1.0), and the best cutoff was 12.4% (sensitivity, 89%

specificity, 100%). A noninferiority test showed that dIVC cannot replace PPV to predict fluid responsiveness (P = .28). Conclusion: The individual PPV discriminative properties for predicting fluid responsiveness in postoperative patients seemed superior to those of dIVC. (C) 2016 Elsevier Inc. All rights reserved.