Mukerji A, Belik J, Sanchez-Luna M
Division of Neonatology, Department of Pediatrics, Hospital for Sick Children, University of Toronto, Toronto, ON, Canada.
Division of Neonatology, Instituto de Investigación Sanitaria Gregorio Marañón, Hospital General Universitario "Gregorio Marañón", University Complutense of Madrid, Madrid, Spain.
J Perinatol. 2014 Jun;34(6):464-7. doi: 10.1038/jp.2014.39. Epub 2014 Mar 13.
To examine the role of frequency in high-frequency ventilation (HFV) on carbon-dioxide (CO2) elimination and lung injury, independent of its effect on tidal volume.
An anatomically representative lung model was attached to a mechanical ventilator capable of providing HFV with a constant volume. CO2 was infused directly into the lung, and a commercially available end-tidal CO2 detector was used to determine CO2 elimination. CO2 elimination and amplitude of pressure transmissions were evaluated using frequencies ranging from 5 to 15 Hz. The pressure-volume index (PVI) was described as the product of the volume and pressures delivered to the lung, a surrogate for lung injury.
The use of increasing frequencies directly correlated with improved CO2 clearance when keeping the tidal volume fixed, expressed as percent CO2 remaining in the lung at 25 s (66.5 (±1.1)%, 50.5 (±0.1)% and 37.8 (±0.3)% at 5, 10 and 15 Hz, respectively, P<0.05). With a fixed tidal volume, there was a decrease in pressure amplitudes transmitted to the lung with a decline in the PVI (53.9 (±2.7) mmHg ml(-1), 41.1 (±0.9) mmHg ml(-1) and 23.4 (±3.6) mmHg ml(-1), at 5, 10 and 15 Hz, respectively, P<0.05).
Frequency has a direct relationship with CO2 elimination when tidal volume is fixed. Using low delivered tidal volumes and high frequencies may allow for improved ventilation efficacy, while minimizing lung injury.
研究在高频通气（HFV）中频率对二氧化碳（CO₂）清除及肺损伤的作用，排除其对潮气量的影响。
将一个具有解剖学代表性的肺模型连接到一台能够提供恒容高频通气的机械通气机上。将CO₂直接注入肺内，并使用市售的呼气末CO₂探测器来测定CO₂清除情况。使用5至15赫兹的频率评估CO₂清除及压力传递幅度。压力-容积指数（PVI）定义为输送至肺的容积与压力的乘积，作为肺损伤的替代指标。
在潮气量固定时，频率增加与CO₂清除改善直接相关，以25秒时肺内剩余CO₂百分比表示（5赫兹时为66.5（±1.1）%，10赫兹时为50.5（±0.1）%，15赫兹时为37.8（±0.3）%，P<0.05）。在潮气量固定的情况下，随着PVI下降，传递至肺的压力幅度降低（5赫兹时为53.9（±2.7）mmHg/ml，10赫兹时为41.1（±0.9）mmHg/ml，15赫兹时为23.4（±3.6）mmHg/ml，P<0.05）。
潮气量固定时，频率与CO₂清除直接相关。使用低输送潮气量和高频率可能会提高通气效率，同时使肺损伤最小化。
