The Ability of Carbon Dioxide-Derived Indices to Predict Adverse Outcome After Cardiac Surgery

J Cardiothorac Vasc Anesth. 2021 Dec;35(12):3604-3611. doi: 10.1053/j.jvca.2021.04.039. Epub 2021 May 3.

Abstract

Objective: The objective of this study was to assess whether the central venous-to-arterial carbon dioxide partial-pressure difference (ΔPCO2) and the ratio of the ΔPCO2 to the arterial-venous difference in oxygen content (ΔPCO2/Ca-vO2) predict postoperative complications (PC) after cardiac surgery.

Design: Prospective, observational, noninterventional study.

Participants: The study comprised 60 patients undergoing cardiac surgery with cardiopulmonary bypass.

Interventions: The primary endpoint was the occurrence of PC. Data were first analyzed in two groups based on the occurrence of PC. Then, receiver operating characteristic curves of the ΔPCO2 and the ΔPCO2/Ca-vO2 ratio were analyzed for the prediction of PC.

Measurements and main results: Among the study participants, 22 (36.7%) experienced PC. The death rate was 18.3%. The present study found that the ΔPCO2 and the ΔPCO2/Ca-vO2 ratio predicted the occurrence of PC with areas under the curve of 0.702 and 0.666, respectively. The best thresholds of these markers were 8.3 mmHg for the ΔPCO2 and 2.16 mmHg/mL for the ΔPCO2/Ca-vO2 ratio. A significant difference was found for these indicators between the groups with and without PC. The ΔPCO2 and the ΔPCO2/Ca-vO2 ratio were significantly correlated to EuroSCORE II, duration of aortic clamping, majority of prognostic scores the first two days postoperatively, and the lactate level. The ΔPCO2/Ca-vO2 ratio is predictive of hyperlactatemia >2 mmol/L, with an area under the curve of 0.787.

Conclusion: The ΔPCO2 and the ΔPCO2/Ca-vO2 ratio predict the occurrence of complications in cardiac surgery.

Keywords: cardiac surgery; cardiopulmonary bypass; central venous-to-arterial carbon dioxide partial- pressure difference; central venous-to-arterial carbon dioxide partial-pressure difference to arterial-venous difference in oxygen content ratio; postoperative complications.

MeSH terms

  • Blood Gas Analysis
  • Carbon Dioxide*
  • Cardiac Surgical Procedures* / adverse effects
  • Cardiopulmonary Bypass / adverse effects
  • Humans
  • Oxygen
  • Prospective Studies

Substances

  • Carbon Dioxide
  • Oxygen