Assessment of Fluid Responsiveness by Changes in End Tidal Carbon Dioxide During Passive Leg Raising Test and Fluid...

It is rationale to predict fluid responsiveness for optimum hemodynamic management. Passive Leg Raising (PLR) causes reversible increase in cardiac output (CO) and changes in end-tidal CO2& pressure (ETCO2 ) can be considered surrogate for CO variations. We aimed to assess the variations in EtCO2 with PLR and fluid challenge (FC) and also compared it with systolic arterial pressure (SAP), mean arterial pressure (MAP), heart rate (HR) and central venous pressure (CVP).

This Prospective study was conducted in the ICU of a tertiary care teaching public hospital. PLR was performed before FC in patients of circulatory failure on mechanical ventilation. ETCO2 and hemodynamics were monitored and compared and correlated after PLR and FC. ROC curve of parameters, based on their Area under the Curve (AUC) was compared. MS Excel, PSPP version 1.0.1 was used for analysis.

Among hundred patients studied, 74 showed ETCO2 change≥ 2 mmHg (>5%) and were fluid responders. Increase in Etco2 after PLR at 1minute and FC at 30 minutes was statistically significant (p=2.73×10-73) so is SAP(p=4.02×10-75) and MAP(p=1.75×10-75). AUC of predictive performance of parameters showed change in ETCO2 (AUC ROC 0.985 [0.938 to 0.999]) had significantly outperformed CVP (AUCROC 0.822 [0.733-0.892]), SAP (AUCROC 0.793 [0.701-0.868]), MAP (AUCROC 0.810 [0.719-0.881]), HR (AUCROC 0.574 [0.471-0.673]).

Conclusion: Variations in ETCO2 >5% induced by PLR can predict fluid responsiveness and is a reliable, non-invasive, easy, quick, and reversible method. ETCO2 is better predictor than SAP, MAP, CVP, and HR during PLR and FC. We may recommend PLR-induced changes in ETCO2 to predict fluid responsiveness in mechanically ventilated patients.