Application of pressure of end-tidal carbon dioxide concentration in polysomnography / 中华耳鼻咽喉头颈外科杂志

<p><b>OBJECTIVE</b>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.</p><p><b>METHODS</b>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.</p><p><b>RESULTS</b>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).</p><p><b>CONCLUSIONS</b>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.</p>

Value of pulse transit time in detecting respiratory drive / 中华耳鼻咽喉头颈外科杂志

<p><b>OBJECTIVE</b>To assess the accuracy of pulse transit time (PTT) in classification of apnea events, and collect data for clinical application reference.</p><p><b>METHODS</b>Thirty-two obstructive sleep apnea-hypopnea syndrome (OSAHS) patients included in the research had Polysomnography (PSG), and 10 305 apnea events were recorded. All the events were analyzed by PTT and esophageal pressure (Pes) respectively. The results were analyzed to assess the accuracy of PTT and compare the accuracy of pulse transit time between REM stage and NREM stage, and analyze the correlation between age, body mass index (BMI), apnea hypopnea index (AHI) and concordance rate in every patient.</p><p><b>RESULTS</b>The total concordance rate between PTT and Pes in classification of apnea was 96.7% (9970/10305). The sensitivities of PTT in detecting central, mixed and obstructive apnea were 88.0%, 91.3% and 97.8% respectively and the specificities were 99.8%, 97.8% and 92.8% respectively. The false determinations of apnea events mainly concentrated on the false determinations between the obstructive and mixed apnea. There was no statistical significant between the accuracy of PTT in different sleep stages. There was a negative relationship between the age, BMI, Lowest SaO2, AHI and the concordance rate.</p><p><b>CONCLUSIONS</b>There was good concordance between PTT and Pes in classification of apnea. PTT had very high sensitivity and specificity in detecting all kinds of apnea. This study showed that PTT can detect respiratory drive noninvasively with high accuracy.</p>