Correlation between Changes in End-Tidal Carbon Dioxide and Stroke Volume Variation Detected by Electrical Cardiometry as a Predictor of Fluid Volume Responsiveness in Hemodynamically Unstable Patients in the Intensive Care

Background: The requirement for cardiac output (CO) measurements typically restricts the widely used passive leg raising (PLR) test for a set of patients because they need costly or intrusive hemodynamic surveillance equipment. This trial aimed to evaluate the role of end-tidal CO2 pressure (EtCO2) monitoring in the prediction of the fluid responsiveness in connection to stroke volume variation (SVV) observed in unstable hemodynamic patients in electrical cardiometry (EC).

Methods: This prospective observational study was carried out on 60 cases aged 18 years or above with hypotension and mechanically ventilated patients in critical care. Patients were classified into two groups according to the SVV:a) Responder group (SVV≥10%) and b) non-responder group. All patients were mechanically ventilated and received sedation and muscle relaxation with no spontaneous respiratory effort.

Results: EtCO2 was significantly increased in responder group than non-responder group at the end (P value = 0.002). SVV was significantly higher in responder group than non-responder group at the baseline (P <0.001). There was a significant negative correlation between SVV and EtCo2 (r = -0.456, P <0.001) and a significant positive correlation between cardiac index and EtCO2 (r = -0.456, P = 0.005). Ä EtCO2 can predict fluid responsiveness significantly (P <0.001) at cut-off > 3 mmHg with 81.4% sensitivity, 88.24% specificity.

Conclusion: EtCO2 existed as a simple, inexpensive, and non-invasive alternative for the CO in the evaluation of various shock conditions. Ä EtCO2 can also predict fluid responsiveness significantly (P <0.001) at cut-off > 3 mmHg with 81.4% sensitivity, 88.24% specificity.