Strategy to Reduce Hypercapnia in Robot-Assisted Radical Prostatectomy Using Transcutaneous Carbon Dioxide Monitoring: A Prospective Observational Study

摘要

Purpose: Monitoring end-tidal carbon dioxide partial pressure (P ET CO 2 ) is a noninvasive, continuous method, but its accuracy is reduced by prolonged capnoperitoneum and the steep Trendelenburg position in robot-assisted radical prostatectomy (RARP). Transcutaneous carbon dioxide partial pressure (P TC CO 2 ) monitoring, which is not affected by ventilator–perfusion mismatch, has been suggested as a suitable alternative. We compared the agreement of noninvasive measurements with the arterial carbon dioxide partial pressure (PaCO 2 ) over a long period of capnoperitoneum, and investigated its sensitivity and predictive power for detecting hypercapnia. Patients and Methods: The patients who underwent RARP were enrolled in this study prospectively. Intraoperative measurements of P ET CO 2 , P TC CO 2 , and PaCO 2 were analyzed. The primary outcome was the agreement of noninvasive monitoring with PaCO 2 during prolonged capnoperitoneum. Bias and precision between noninvasive measurements and PaCO 2 were assessed using Bland–Altman analysis. The bias and mean absolute difference were compared using a two-tailed Wilcoxon signed-rank test for pairs. The secondary outcome was the sensitivity and predictive power for detecting hypercapnia. To assess this, the Yates corrected chi-square test and the area under the receiver operating characteristic curve were used. Results: The study analyzed 219 datasets from 46 patients. Compared with P ET CO 2 , P TC CO 2 had lower bias, greater precision, and better agreement with PaCO 2 throughout the RARP. The mean absolute difference in P ET CO 2 and PaCO 2 was larger than that of P TC CO 2 and PaCO 2, and continued to exceed the clinically acceptable range of 5 mmHg after 1 hour of capnoperitoneum. The sensitivity during capnoperitoneum and overall predictive power of P TC CO 2 for detecting hypercapnia were significantly higher than those of P ET CO 2 , suggesting a greater contribution to ventilator adjustment, to treat hypercapnia. Conclusion: P TC CO 2 monitoring measured PaCO 2 more accurately than P ET CO 2 monitoring during RARP requiring prolonged capnoperitoneum and a steep Trendelenburg position. P TC CO 2 monitoring also provides more sensitive measurements for ventilator adjustment and detects hypercapnia more effectively than P ET CO 2 monitoring. Keywords: intraoperative carbon dioxide monitoring, capnoperitoneum, robotic surgery, end-tidal carbon dioxide monitoring, general anesthesia