End-tidal carbon dioxide concentration monitoring in obstructive sleep apnea patients

ArticleinAmerican journal of otolaryngology 32(3):190-3 · May 2010with57 Reads
DOI: 10.1016/j.amjoto.2010.01.006 · Source: PubMed
The objective of this study was to investigate the end-tidal carbon dioxide concentration (ETco(2)) monitoring in obstructive sleep apnea (OSA) patients during sleep and to explore whether the ETco(2) value may explain a significant portion of the relationship between ETco(2) value and apnea/hypopnea index (AHI) and nocturnal oxygenation indices. Thirty-eight consecutive patients underwent overnight polysomnography and were synchronously monitored for ETco(2) using an microstream capnometer. Mean and maximum values during wake time and different sleep stages were recorded. We grouped 38 OSA patients into 2 subgroups on the basis of their difference of mean total sleep time and wake time ETco(2) [(T - W) ETco(2)]; one group, 20 patients with (T - W) ETco(2) less than 0, and the other group,18 patients with (T - W) ETco(2) greater than 0. Group with (T - W) ETco(2) less than 0 patients exhibited higher AHI (mean ± SD, 68.58 ± 22.78 vs. 27.61 ± 19.44 events/h) and lower nocturnal oxygenation indices (minimum Sao(2), 67.85 ± 10.08 vs. 82.61% ± 6.07%; mean Sao(2), 91.29 ± 3.31 vs. 95.15% ± 1.88%) compared with the other group. In summary, the study provides preliminary data showing that ETco(2) potentially can be used in continuous monitoring of OSA patients. And, (T - W) ETco(2) can indicate the severity of OSA.
    • "In addition to abnormal anatomical structures, weak or absence of the neural control on respiration is also an important factor. Many studies have confirmed the important role of muscle excitability on respiration123456789 . With the help of polysomnography , it can be found that neuromuscular myoelectricity around upper airway is higher for OSAS patients than normal person in the daytime while drops sharply during sleep especially rapid eye movement sleep. "
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