Bond D M, McAloon J, Froese A B
Department of Anaesthesia, Queen's University, Kingston, ON, Canada.
Crit Care Med. 1994 Aug;22(8):1269-77. doi: 10.1097/00003246-199408000-00011.
To determine whether volume recruitment maneuvers that induce significant lung reexpansion during high-frequency oscillatory ventilation are also of value during conventional positive-pressure ventilation.
Crossover comparison of volume recruitment maneuvers administered during high-frequency oscillatory ventilation and positive-pressure ventilation in normal and surfactant-deficient adult rabbits.
Laboratory.
Nineteen adult New Zealand white rabbits (weight 2.3 to 3.3 kg).
Respiratory system compliance was measured plethysmographically before and after sustained inflations in six normal and five saline-lavaged anesthetized rabbits, using both ventilators over a range of mean and end-expiratory pressures.
Under conditions where sustained inflations during high-frequency oscillatory ventilation at 15 Hz increased respiratory system compliance 50 +/- 28%, sustained inflations during conventional positive-pressure ventilation at a rate of 30 to 40 breaths/min and tidal volumes of 14 to 17 mL/kg did not change respiratory system compliance (mean change 3 +/- 9%). Sustained inflations during conventional positive-pressure ventilation could not be made effective by increasing the positive end-expiratory pressure level to equal the mean pressure during high-frequency oscillatory ventilation. Sustained inflations on conventional positive-pressure ventilation remained ineffective up to positive end-expiratory pressure levels of 17.5 cm H2O. In lavaged rabbits, sustained inflations increased respiratory system compliance 49 +/- 14% during high-frequency oscillatory ventilation and 0 +/- 3% during conventional positive-pressure ventilation. Sustained inflations increased compliance significantly during conventional positive-pressure ventilation only when ventilating with tidal volumes of 7 mL/kg and low end-expiratory pressure.
Active recruitment of lung volume during high-frequency oscillatory ventilation appears necessary, because small pressure/volume cycles adequate to support high-frequency gas transport are not able to reexpand atelectatic lung units without the aid of a sustained inflation. We conclude that volume recruitment maneuvers improve respiratory system compliance substantially during high-frequency oscillatory ventilation at 15 Hz, but these maneuvers offer potential risk and no benefit during conventional positive-pressure ventilation with large tidal volumes or when using smaller tidal volumes and high levels of positive end-expiratory pressure.
确定在高频振荡通气期间能引起显著肺复张的肺容积复张手法在传统正压通气期间是否也有价值。
对正常及缺乏表面活性物质的成年兔在高频振荡通气和正压通气期间实施的肺容积复张手法进行交叉比较。
实验室。
19只成年新西兰白兔（体重2.3至3.3千克）。
在6只正常和5只盐水灌洗麻醉的兔子中，使用两种通气机在一系列平均压力和呼气末压力下，通过体积描记法测量持续充气前后的呼吸系统顺应性。
在15赫兹高频振荡通气期间持续充气使呼吸系统顺应性增加50±28%的情况下，以30至40次/分钟的频率和14至17毫升/千克的潮气量进行传统正压通气时，持续充气并未改变呼吸系统顺应性（平均变化3±9%）。将呼气末正压水平提高到等于高频振荡通气期间的平均压力，也无法使传统正压通气期间的持续充气有效。在呼气末正压水平达到17.5厘米水柱之前，传统正压通气的持续充气仍然无效。在灌洗兔中，高频振荡通气期间持续充气使呼吸系统顺应性增加49±14%，而传统正压通气期间增加0±3%。仅在以7毫升/千克的潮气量和低呼气末压力通气时，传统正压通气期间的持续充气才显著增加顺应性。
高频振荡通气期间主动复张肺容积似乎是必要的，因为在没有持续充气辅助的情况下，足以支持高频气体传输的小压力/容积周期无法使肺不张的肺单位复张。我们得出结论，肺容积复张手法在15赫兹高频振荡通气期间能显著改善呼吸系统顺应性，但在大潮气量的传统正压通气期间或使用小潮气量和高水平呼气末正压时，这些手法存在潜在风险且无益处。
