A Novel Mainstream Capnometer System for Non-invasive Positive Pressure Ventilation.

Abstract

Capnometry is a method to measure carbon dioxide (CO2) in exhaled gas and it has been used to monitor patient respiratory status. CO2 monitoring is also used for patients receiving non-invasive positive pressure ventilation (NPPV) therapy during mechanical ventilation. Ventilators actively dilute exhaled gas during non-invasive ventilation. In order to accurately measure end-tidal CO2, an adequate amount of expired gas needs to be filled in a CO2 measurement cell before expiratory positive airway pressure (EPAP) gas from the ventilator arrives to the cell. This is the reason why it is difficult to measure CO2 stably during non-invasive ventilation using the conventional CO2 measurement method. Therefore, we developed NPPV cap-ONE mask, which accurately measures CO2 in exhaled gas during non-invasive ventilation. In this study, we evaluated the basic performance of the NPPV cap-ONE mask system. The NPPV cap-ONE mask system could accurately measure CO2 in exhaled gas comparing to the conventional device in this study.