Is central venous - artery co2 difference effective in the prediction of postoperative complications in high risk operations?

Objective: The development of tissue hypoxia during major surgical intervention is the leading cause of organ failure and mortality in the postoperative period. In high-risk surgical patients, maintaining tissue perfusion at an adequate level during intervention reduces the risk of developing postoperative complications. For that reason, it is important that tissue hypoxia is identified early and oxygenation is ensured. The aim of this study was to assess the relevance of high values for ΔPCO2 in relation to clinical suitability and other markers of impaired tissue perfusion and oxygenation such as blood lactation. The primary purpose of our study was to observe the veno-arterial pCO2 differential values in the intraoperative period and its relation to the development of postoperative complications. Veno-arterial PCO2 difference values were also observed in the postoperative period and it was planned to examine the relationship between the values in the two periods with each other and the frequency of complication. Materials and Methods: Totally 138 patients who underwent surgical intervention between December 1, 2017 and May 1, 2018 in the Istanbul University Istanbul Medical School operating theaters by setting various exclusion criteria for the study were included. for study. The approval for the study was obtained from the Istanbul Medical Faculty Ethics Committee for Clinical Investigations and the patients were included in the study after consent was obtained. Standardized anesthesia monitoring was performed in the hospital room. Arterial and venous blood gas samples were taken at the end of the patient's anesthesia induction, at the 2nd hour and at the end ofta operation. After the surgical procedure was completed, the patient was removed to the intensive care unit in the orotracheal intubated and monitored. Results: The mean age of the patients was 66.7 ± 10.8 years. The mortality rate was found to be 4.3% and it was found that the difference between the groups with and without complication in terms of mortality was significant (p = 0.011). The results of univariate analysis revealed that there was a statistically significant difference between the mean intraoperative age, arterial oxygen pressure, ΔPCO2, ScvO2 and lactate values between the groups with and without complication (p <0.05). In the multivariate analysis for predicting the postoperative complication, age (Odds Ratio: 1.08 (95% Confidence Interval: 1.01-1.15), p = 0.014) and postoperative ΔPCO2 (Odds Ratio: 3.48 (95% Confidence Interval: 2.09-2.57) ) were found to be independent factors in terms of predicting postoperative complications. The difference between the predictive powers of postoperative ΔPCO2 and postoperative lactate values in terms of postoperative complication development was statistically significant (p <0.0001). In addition, the difference between the predictive values of postoperative ΔPCO2 and SOFA in terms of dicrimination of postoperative complication development was not statistically significant (p=0.18). Conclusions: The main outcome of our study is the necessity of resuscitation when the threshold of ΔPCO2 is 6.6 mmHg in the intraoperative period and 7.5 mmHg in the postoperative period in high risk surgical patients and should be alert to the complication development. Keywords:Veno-arterial PCO2 difference,tissue perfusion,postoperative complication