Assessment of changes in cardiac index with calibrated pulse contour analysis in cardiac surgery: A prospective observational study

Abstract Objectives To assess the trending ability of calibrated pulse contour cardiac index (CI PC ) monitoring during haemodynamic changes (passive leg raising [PLR] and fluid loading) compared with transpulmonary thermodilution CI (CI TD ). Method Seventy-eight mechanically-ventilated patients admitted to intensive care with calibrated pulse contour following cardiac surgery were prospectively included and investigated during PLR, and after fluid loading. Fluid responsiveness was defined as a ≥ 15% CI TD increase after a 500 ml bolus. Areas under the empiric receiver operating characteristic curves (ROC AUC ) for changes in CI PC (ΔCI PC ) during PLR to predict fluid responsiveness and after fluid challenge to predict an increase at least 15% in CI TD after fluid loading were calculated. Results Fifty-five patients (71%) were classified as responders, 23 (29%) as non-responders. ROC AUC for ΔCI PC during PLR in predicting fluid responsiveness, its sensitivity, specificity, and percentage of patients within the inconclusive class of response were 0.67 (95% CI = 0.55–0.77), 0.76 (95% CI = 0.63–0.87), 0.57 (95% CI = 0.34–0.77) and 68%, respectively. Bias, precision and limits of agreements and percentage error between CI PC and CI TD after fluid challenge were 0.14 (95% CI: 0.08–0.20), 0.26, –0.37 to 0.64 l min −1  m −2 , and 20%, respectively. The concordance rate was 97% and the polar concordance at 30° was 91%. ROC AUC for ΔCI PC in predicting an increase of at least 15% in CI TD after fluid loading was 0.85 (95% CI: 0.76–0.92). Conclusion Although ΔCI PC after fluid loading could track the direction of changes of CI TD and was interchangeable with bolus transpulmonary thermodilution, PLR could not predict fluid responsiveness in cardiac surgery patients.