Imanaka Hideaki, Takeuchi Muneyuki, Tachibana Kazuya, Takauchi Yuji, Inamori Noriko, Nishimura Masaji
Department of Surgical Intensive Care Unit, National Cardiovascular Center, Suita.
Masui. 2005 Mar;54(3):254-9.
We investigated effects of cardiogenic oscillation on overestimation of tidal volume using a lung model, with three ventilators and two ventilatory modes.
We simulated cardiogenic oscillation at a rate of 90 breaths x min(-1) by ventilating one bellow of a two-bellow-type lung model. The magnitude of cardiogenic oscillation was defined as peak expiratory flow fluctuation when the airway was opened to the atmosphere. The lung model was mechanically ventilated with three ventilators (Bird 8400 STi, Servo-300, and Nellcor Puritan-Bennett 840), two ventilatory modes (volume- and pressure-controlled ventilation), and two respiratory rates (5 and 10 breaths x min(-1)) in random order. We recorded tidal volume on a ventilator monitor and calculated the discrepancy from the set tidal volume.
With Bird 8400 STi, monitored tidal volume exceeded set tidal volume, regardless of volume- or pressure-controlled ventilation. The overestimation in tidal volume was larger with smaller respiratory rate and with larger cardiogenic oscillation. In contrast, with the other ventilators, the discrepancy was small.
Exhaled tidal volume is overestimated during mechanical ventilation when cardiogenic oscillation is large.
我们使用一个肺模型、三台呼吸机和两种通气模式，研究了心源性振荡对潮气量高估的影响。
通过对双腔式肺模型的一个腔进行通气，我们以90次呼吸×分钟⁻¹的频率模拟心源性振荡。心源性振荡的幅度定义为气道向大气开放时的呼气峰值流量波动。肺模型使用三台呼吸机（Bird 8400 STi、Servo - 300和Nellcor Puritan - Bennett 840）、两种通气模式（容量控制通气和压力控制通气）以及两种呼吸频率（5次和10次呼吸×分钟⁻¹）进行随机顺序的机械通气。我们在呼吸机监测器上记录潮气量，并计算与设定潮气量的差异。
使用Bird 8400 STi时，无论采用容量控制通气还是压力控制通气，监测到的潮气量均超过设定潮气量。呼吸频率越小且心源性振荡越大，潮气量的高估就越明显。相比之下，使用其他呼吸机时，差异较小。
当心源性振荡较大时，机械通气过程中呼出的潮气量会被高估。
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