Mols G, von Ungern-Sternberg B, Rohr E, Haberthür C, Geiger K, Guttmann J
Section of Experimental Anesthesiology, the University of Freiburg, Germany.
Crit Care Med. 2000 Jun;28(6):1940-6. doi: 10.1097/00003246-200006000-00042.
To assess respiratory comfort and associated breathing pattern during volume assist (VA) as a component of proportional assist ventilation and during pressure support ventilation (PSV).
Prospective, double-blind, interventional study.
Laboratory.
A total of 15 healthy volunteers (11 females, 4 males) aged 21-31 yrs.
Decreased respiratory system compliance was simulated by banding of the thorax and abdomen. Volunteers breathed via a mouthpiece with VA and PSV each applied at two levels (VA, 8 cm H2O/L and 12 cm H2O/L; PSV, 10 cm H2O and 15 cm H2O) using a positive end-expiratory pressure of 5 cm H2O throughout. The study was subdivided into two parts. In Part 1, volunteers breathed three times with each of the four settings for 2 mins in random order. In Part 2, the first breath effects of multiple, randomly applied mode, and level shifts were studied.
In Part 1, the volunteers were asked to estimate respiratory comfort in comparison with normal breathing using a visual analog scale. In Part 2, they were asked to estimate the change of respiratory comfort as increased, decreased, or unchanged immediately after a mode shift. Concomitantly, the respiratory pattern (change) was characterized with continuously measured tidal volume, respiratory rate, pressure, and gas flow. Respiratory comfort during VA was higher than during PSV. The higher support level was less important during VA but had a major negative influence on comfort during PSV. Both modes differed with respect to the associated breathing pattern. Variability of breathing was higher during VA than during PSV (Part 1). Changes in respiratory variables were associated with changes in respiratory comfort (Part 2).
For volunteers breathing with artificially reduced respiratory system compliance, respiratory comfort is higher with VA than with PSV. This is probably caused by a better adaptation of the ventilatory support to the volunteer's need with VA.
评估在作为比例辅助通气组成部分的容积辅助（VA）期间以及压力支持通气（PSV）期间的呼吸舒适度及相关呼吸模式。
前瞻性、双盲、干预性研究。
实验室。
共15名年龄在21 - 31岁的健康志愿者（11名女性，4名男性）。
通过束缚胸部和腹部来模拟呼吸系统顺应性降低。志愿者通过咬嘴呼吸，在整个过程中呼气末正压为5 cm H₂O，VA和PSV均采用两个水平（VA，8 cm H₂O/L和12 cm H₂O/L；PSV，10 cm H₂O和15 cm H₂O）。研究分为两部分。在第1部分中，志愿者以随机顺序对四种设置中的每一种进行3次2分钟的呼吸。在第2部分中，研究了多种随机应用模式和水平转换的首次呼吸效应。
在第1部分中，要求志愿者使用视觉模拟量表与正常呼吸相比评估呼吸舒适度。在第2部分中，要求他们在模式转换后立即评估呼吸舒适度的变化是增加、减少还是不变。同时，通过连续测量潮气量、呼吸频率、压力和气流来表征呼吸模式（变化）。VA期间的呼吸舒适度高于PSV期间。在VA期间较高的支持水平不太重要，但对PSV期间的舒适度有重大负面影响。两种模式在相关呼吸模式方面存在差异。VA期间的呼吸变异性高于PSV期间（第1部分）。呼吸变量的变化与呼吸舒适度的变化相关（第2部分）。
对于呼吸系统顺应性人为降低的志愿者，VA的呼吸舒适度高于PSV。这可能是由于VA的通气支持更好地适应了志愿者的需求。
