Application of pressure of end-tidal carbon dioxide concentration in polysomnography

Abstract

The purpose of this study was to investigate the end-tidal carbon dioxide concentration (PETCO2) monitoring coupling in polysomnography for patients with obstructive sleep apnea hypopnea syndrome (OSAHS) during sleep. PETCO2 was sampled through a Oral-Nasal Cannula and measured using micro-stream capnometer. Capnometer was calibrated according to the manufacturer instructions and integrated into the standard polysomnographic recordings. Thirty-eight consecutive patients underwent overnight polysomnography (PSG) were synchronously monitored PETCO2. All variables were recorded continuously and transferred to a computer for analysis. PETCO2 numeric values and waveform were displayed in real time on the PSG epoch. The mean PETCO2 of wake, non-rapid eye movement, rapid eye movement and TST(?) were negatively correlated with apnea-hypopnea index and arousal index (r were -0.458 ∼ -0.688, P < 0.01), were positively correlated with mean arterial oxygen saturation (SaO2) and lowest SaO2, (r were 0.604 ∼ 0.674, P < 0.01). The study provides preliminary data showing that PETCO2 potentially can be used in continuous monitoring of OSAHS patients. And PETCO2 can indicate the severity of OSAHS.