Division of Pulmonary Diseases, Geneva University Hospital, Geneva, Switzerland.
Intensive Care Unit, and CRC & Division of Cinical-Epidemiology, Geneva University Hospital, Geneva, Switzerland.
Chest. 2012 Feb;141(2):469-476. doi: 10.1378/chest.11-0485. Epub 2011 Jul 21.
Current bilevel positive-pressure ventilators for home noninvasive ventilation (NIV) provide physicians with software that records items important for patient monitoring, such as compliance, tidal volume (Vt), and leaks. However, to our knowledge, the validity of this information has not yet been independently assessed.
Testing was done for seven home ventilators on a bench model adapted to simulate NIV and generate unintentional leaks (ie, other than of the mask exhalation valve). Five levels of leaks were simulated using a computer-driven solenoid valve (0-60 L/min) at different levels of inspiratory pressure (15 and 25 cm H(2)O) and at a fixed expiratory pressure (5 cm H(2)O), for a total of 10 conditions. Bench data were compared with results retrieved from ventilator software for leaks and Vt.
For assessing leaks, three of the devices tested were highly reliable, with a small bias (0.3-0.9 L/min), narrow limits of agreement (LA), and high correlations (R(2), 0.993-0.997) when comparing ventilator software and bench results; conversely, for four ventilators, bias ranged from -6.0 L/min to -25.9 L/min, exceeding -10 L/min for two devices, with wide LA and lower correlations (R(2), 0.70-0.98). Bias for leaks increased markedly with the importance of leaks in three devices. Vt was underestimated by all devices, and bias (range, 66-236 mL) increased with higher insufflation pressures. Only two devices had a bias < 100 mL, with all testing conditions considered.
Physicians monitoring patients who use home ventilation must be aware of differences in the estimation of leaks and Vt by ventilator software. Also, leaks are reported in different ways according to the device used.
目前用于家庭无创通气（NIV）的双水平正压通气机能为医生提供记录患者监测相关重要项目的软件，如顺应性、潮气量（Vt）和漏气。然而，据我们所知，这些信息的准确性尚未得到独立评估。
在一个经改装以模拟 NIV 并产生非故意漏气（即面罩呼气活瓣以外的漏气）的床旁模型上对 7 台家用通气机进行了测试。在不同吸气压力（15 和 25 cm H2O）和固定呼气压力（5 cm H2O）下，使用计算机驱动的电磁阀模拟了 5 个漏气水平（0-60 L/min），总共有 10 种条件。将床旁数据与通气机软件中获取的漏气和 Vt 结果进行了比较。
在评估漏气时，所测试的 3 台设备高度可靠，偏差较小（0.3-0.9 L/min），一致性界限较窄（LA），并且相关性较高（R2，0.993-0.997），通气机软件和床旁结果之间；相反，对于 4 台通气机，偏差范围从-6.0 L/min 到-25.9 L/min，有两台设备偏差超过-10 L/min，LA 较宽，相关性较低（R2，0.70-0.98）。在 3 台设备中，漏气的重要性越大，漏气的偏差越大。所有设备均低估了 Vt，并且随着充气压力的升高，偏差（范围，66-236 mL）增大。仅两台设备在所有测试条件下的偏差都<100 mL。
监测使用家庭通气的患者的医生必须意识到通气机软件在估计漏气和 Vt 方面的差异。此外，根据使用的设备，漏气的报告方式也不同。
