Division of Pulmonary Diseases, Geneva University Hospitals, Geneva, Switzerland.
Eur Respir J. 2013 Feb;41(2):346-53. doi: 10.1183/09031936.00193911. Epub 2012 Apr 20.
Among the respiratory events that may occur during nocturnal noninvasive ventilation (NIV), differentiating between central and obstructive events requires appropriate indicators of respiratory effort. The aim of the present study was to assess pulse transit time (PTT) as an indicator of respiratory effort under NIV in comparison with oesophageal pressure (P(oes)). During wakefulness, PTT was compared to P(oes) during spontaneous breathing and under NIV with or without induced leaks in 11 healthy individuals. In addition, the contribution of PTT versus P(oes) to differentiation of central from obstructive respiratory events occurring under NIV during sleep was evaluated in 10 patients with obesity hypoventilation syndrome (OHS). From spontaneous breathing to NIV without leaks, respiratory effort decreased significantly whereas, with increasing level of leaks, there was a significant increase in respiratory effort. Changes in PTT accurately reflected changes in P(oes). In OHS patients during nocturnal NIV, intraclass correlation coefficients between P(oes) and PTT were 0.970 for total number of events and 0.970 for percentage of central events. PTT accurately reflects the unloading of respiratory muscles induced by NIV and the increase in respiratory effort during leaks. PTT during sleep is also useful to differentiate central from obstructive respiratory events occurring under NIV.
在夜间无创通气（NIV）期间可能发生的呼吸事件中，区分中枢性和阻塞性事件需要有适当的呼吸努力指标。本研究的目的是评估脉搏传输时间（PTT）作为 NIV 下呼吸努力的指标，并与食管压力（P（oes））进行比较。在清醒状态下，在 11 名健康个体中比较了自主呼吸期间和在 NIV 下（有无诱导漏气）的 PTT 与 P（oes）。此外，还评估了 PTT 与 P（oes）在区分肥胖低通气综合征（OHS）患者睡眠期间 NIV 下发生的中枢性和阻塞性呼吸事件中的作用。从自主呼吸到无漏气的 NIV，呼吸努力显著降低，而随着漏气水平的增加，呼吸努力显著增加。PTT 的变化准确反映了 P（oes）的变化。在 OHS 患者夜间 NIV 期间，P（oes）和 PTT 之间的组内相关系数对于总事件数为 0.970，对于中枢性事件的百分比为 0.970。PTT 准确反映了 NIV 引起的呼吸肌卸载和漏气期间呼吸努力的增加。睡眠期间的 PTT 也有助于区分 NIV 下发生的中枢性和阻塞性呼吸事件。
