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Updated: May 11, 2026

Expired CO2 Measurement in Intubated or Spontaneously Breathing Patients from the Emergency Department
Published on: January 29, 2011
[Application of pressure of end-tidal carbon dioxide concentration in polysomnography]
Wei-hu Chen1, Jing-ying Ye, Yu-huan Zhang
1Department of Otorhinolaryngology Head and Neck Surgery, Beijing Tongren Hospital, Capital Medical University, Key Laboratory of Otorhinolaryngology Head and Neck Surgery, Ministry of Education (Capital Medical University), Beijing 100073, China.
Objective:
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.
Methods:
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.
Results:
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).
Conclusions:
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.
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