TY - JOUR T1 - Evaluation of an Oxygen Mask-Based Capnometry Device in Subjects Extubated After Abdominal Surgery JF - Respiratory Care SP - 705 LP - 710 DO - 10.4187/respcare.03557 VL - 60 IS - 5 AU - Shunsuke Takaki AU - Takahiro Mihara AU - Kenji Mizutani AU - Osamu Yamaguchi AU - Takahisa Goto Y1 - 2015/05/01 UR - http://rc.rcjournal.com/content/60/5/705.abstract N2 - BACKGROUND: For early detection of respiratory and hemodynamic changes during anesthesia, continuous end-tidal carbon dioxide concentration (PETCO2) is monitored by capnometry. However, the accuracy of CO2 monitoring during spontaneous breathing in extubated patients remains undetermined. Therefore, we aimed to compare PETCO2 measured by capnometry using an oxygen mask with a carbon dioxide sampling port (capnometry-type oxygen mask) and PCO2 in extubated subjects who had undergone abdominal surgery. Furthermore, we investigated whether spontaneous deep breathing affected dissociation between PaCO2 and PETCO2. METHODS: Adult post-abdominal surgery subjects admitted to the ICU were enrolled in this study. After extubation, oxygen was supplied at 6 L/min using the capnometry-type oxygen mask. After 30 min of oxygen supply, PaCO2 blood gas analysis was performed, and PETCO2 was measured under resting and deep-breathing conditions. For both resting and deep-breathing conditions, the correlation between PaCO2 and PETCO2 was analyzed. Furthermore, bias, precision, and limits of agreement were calculated using the Bland-Altman method. RESULTS: Twenty-five subjects (15 men, 10 women) with a mean age of 62 y (interquartile range of 57–76 y) and body mass index of 20–24 kg/m2 were studied. The correlation (r) between PaCO2 and PETCO2 under resting and deep-breathing conditions was 0.50 and 0.56, respectively. Compared with PaCO2, the bias and limits of agreement were −12.6 (−20.6 to −4.6) for resting PETCO2 and −9.1 (−16.0 to −2.1) for deep-breathing PETCO2. The association between PaCO2 and deep-breathing PETCO2 was significantly smaller compared with resting PETCO2 (P = .002). CONCLUSIONS: It is possible to measure the PETCO2 under varying breathing conditions with the capnometry-type oxygen mask in subjects receiving oxygen supplementation after extubation following upper abdominal surgery to determine whether they are properly ventilating. (ClinicalTrials.gov registration UMIN000011925.) ER -