end-tidal capnography /end″tīdəl/ , the process of continuously recording the level of carbon dioxide in expired air. The percentage of carbon dioxide at the end of expiration can be estimated and gives a close approximation of the alveolar carbon dioxide concentration. The process, which requires the use of infrared spectroscopy, is used to monitor critically ill patients and in pulmonary function testing. The data are typically recorded automatically on a strip of graph paper on a bedside patient monitor.
