THE ABILITY OF CARBON DIOXYDE-DERIVED INDICES TO PREDICT ADVERSE OUTCOME AFTER CARDIAC SURGERY

ABSTRACT Objective : The objective of this study was to assess the interest of central venous-to- arterial CO2 partial pressure difference (ΔPCO2) and the ratio between central venous-to- arterial CO2 partial pressure difference and arterial-venous difference in oxygen content (ΔPCO2/Ca-vO2) in prediction of postoperative complications (PC) after cardiac surgery. Design : a prospective, observational, non interventional study. Participants : 60 patients undergoing cardiac surgery with cardiopulmonary bypass (CBP). Interventions : The primary endpoint was the occurrence of PC. Data were first analyzed according to 2 groups based on the occurrence of PC. Then, we analyzed the ROC curves of ΔPCO2 and ΔPCO2/Ca-vO2 ratio for prediction of PC. Measurements and main results : Among our patients, 22 (36.7%) presented PC. The death rate was 18.3%. We found that ΔPCO2 and ΔPCO2/Ca-vO2 ratio predict the occurrence of PC with areas under the curve (AUC) at 0.702 and 0.666 respectively. The best thresholds of these markers were 8.3mmHg for ΔPCO2 and 2.16mmHg / ml for the ΔPCO2/Ca-vO2 ratio. A significant difference was found for these indicators between the groups with and without PC. ΔPCO2 and ΔPCO2 / Ca-vO2 ratio were significantly correlated to Euroscore 2, duration of aortic clamping, majority of prognostic scores on the first two days postoperatively and lactate level. ΔPCO2 / Ca-vO2 ratio is predictive of hyperlactatemia> 2mmol / l with an AUC at 0.787. Conclusion : We conclude that ΔPCO2 and ΔPCO2/Ca-vO2 ratio predict the occurrence of complications in cardiac surgery.