Evaluation of a compact device for capnometry of main-stream type compared with one of side-stream type in a postoperative care unit

摘要

BACKGROUND: Pulse oximetry is insufficient for postoperative respiratory monitoring. It is better to use capnometry for postoperative patients because it is easy to use and useful to monitor patients' breathing. However, capnometry must be improved in its wearability and detection capability. Therefore it is not used often for postoperative patients as a respiratory monitor. METHODS: We have examined a side-stream type capnometer and an improved main-stream type capnometer in a post-anesthesia care unit (PACU) to determine which is better as a monitor for detection of breathing. A total of 55 patients participated in this study. Patients wore a device including a main-stream capnometer and a side-stream capnometer. Capnograms were recorded while patients were staying in the PACU. RESULTS: The main-stream system could detect breathing in all the patients, but the side-stream system failed to detect breathing in five patients. The side-stream device showed a warning of "apnea" for five patients, even though these patients were breathing normally. CONCLUSIONS: We conclude that the main-stream system is a better monitor of postoperative respiratory condition.