Continuous monitoring of gastric intraluminal carbon dioxide pressure, cardiac output, and end-tidal carbon dioxide pressure in the perioperative period in patients receiving cardiovascular surgery using cardiopulmonary bypass

Objective: To verify the hypothesis that the gastric intraluminal Pco(2) (Pgco(2)) changes independently of the change in cardiac output (CO) during and after cardiovascular surgery using cardiopulmonary bypass (CPB), and that the elevation Of Pgco(2) affects the patients' morbidity. Design: Prospective, noninterventional study. Setting: Medical/surgical intensive care unit and operating theater of a university hospital. Patients: Sixteen adults patients receiving elective cardiovascular surgery using CPB. Interventions: None. Measurements and Main Results: After induction of anesthesia, the patients were fitted with a gastric tube equipped at the tip with a CO2 sensor (ion-selective field effect transistor) that can continuously measure real-time Pgco(2), and a pulmonary artery catheter capable of monitoring continuous CO (CCO) and end-tidal CO2 Data from the devices was uploaded to a personal computer every 2 mins until the catheter was pulled off based on clinical judgment (Pgco(2) values were blinded to everyone except the investigator). One patient expired as a result of multiple organ failure subsequent to sepsis, and postoperative morbidity assessed by the peak SOFA (sequential organ failure assessment) score (mean +/- SD 6.9 +/- 3.5; range, 2-13) was correlated with the peak Pgco(2) during intensive care unit stay (mean +/- SD 74.1 +/- 30.7 mm Hg; range, 45-169 mm Hg) (p < .01, by regression analysis). The peak Pgco(2) during surgery (mean +/- SD 71.1 +/- 18.1 mm Hg; range, 44-115 mm Hg) had no correlation with the postoperative morbidity. From analysis of CCO before, during, and after returning from the above 60 mm Hg of Pgco(2), Pgco(2) changed independently of CCO. Conclusions: Pgco(2) changed independently of CCO, and its postoperative elevation was related to morbidity, even in the group of patients with a good outcome. Continuous monitoring of Pgco(2) is useful for the detection of morbidity and can be expected to help elucidate the pathophysiology of change of Pgco(2).