A Comparison of Transcutaneous and End-tidal Measurements of CO2 in One Lung Ventilation / 대한마취과학회지

ABSTRACT

BACKGROUND: In thoracic anesthesia with one lung ventilation (OLV), end-tidal CO2 (PeTCO2) monitoring may not be accurate to estimate PaCO2 mainly due to ventilation/perfusion mismatching.This study aimed to asses the clinical usefulness and accuracy of a transcutaneous CO2 (PtCCO2) monitoring in thoracic anesthesia, compared with PeTCO2. METHODS: 18 patients of ASA physical status 1 or 2, required a long period of OLV were researched.The lungs were mechanically ventilated in the lateral decubitus position.We measured PaCO2, PeTCO2, PtCCO2 during two lung ventilation (TLV) and 15 min, 30 min, 60 min after OLV.For comparing the differences of PtCCO2/PaCO2 and PtCCO2/PaCO2, we figured out bias (mean difference between values) and precision (standard deviation of bias) by using Bland-Altman plot.We compared the differences of each value, PeTCO2/PaCO2, PtCCO2/PaCO2, using the student's t-test. RESULTS: The bias +/- precision of PeTCO2/PaCO2 and PtCCO2/PaCO2 was each 7.82 mmHg +/- 3.98 mmHg, 1.95 mmHg +/- 2.66 mmHg during TLV and that of mean value of PeTCO2/PaCO2 and PtCCO2/PaCO2 was each 6.93 mmHg +/- 2.6 mmHg, 2.35 mmHg +/- 1.66 mmHg during OLV.PtCCO2/PaCO2 differences were significantly less than PeTCO2/PaCO2 differences (P < 0.05). CONCLUSIONS: During one lung ventilation, PtCCO2 monitoring is more useful and accurate than PeTCO2 monitoring for assessing PaCO2 levels.