Department of Biomedical Technology, Faculty of Biomedical Engineering, Czech Technical University in Prague, nam. Sitna 3105, 272 01, Kladno, Czech Republic.
Institute of Physiology, First Faculty of Medicine, Charles University, Albertov 5, 128 00, Prague, Czech Republic.
Biomed Eng Online. 2022 Feb 13;21(1):14. doi: 10.1186/s12938-022-00984-x.
The role of high-frequency oscillatory ventilation (HFOV) has long been debated. Numerous studies documented its benefits, whereas several more recent studies did not prove superiority of HFOV over protective conventional mechanical ventilation (CV). One of the accepted explanations is that CV and HFOV act differently, including gas exchange.
To investigate a different level of coupling or decoupling between oxygenation and carbon dioxide elimination during CV and HFOV, we conducted a prospective crossover animal study in 11 healthy pigs. In each animal, we found a normocapnic tidal volume (V) after the lung recruitment maneuver. Then, V was repeatedly changed over a wide range while keeping constant the levels of PEEP during CV and mean airway pressure during HFOV. Arterial partial pressures of oxygen (PO) and carbon dioxide (PCO) were recorded. The same procedure was repeated for CV and HFOV in random order.
Changes in PCO intentionally induced by adjustment of V affected oxygenation more significantly during HFOV than during CV. Increasing V above its normocapnic value during HFOV caused a significant improvement in oxygenation, whereas improvement in oxygenation during CV hyperventilation was limited. Any decrease in V during HFOV caused a rapid worsening of oxygenation compared to CV.
A change in PCO induced by the manipulation of tidal volume inevitably brings with it a change in oxygenation, while this effect on oxygenation is significantly greater in HFOV compared to CV.
高频振荡通气（HFOV）的作用一直存在争议。许多研究证明了它的益处，而最近的几项研究则没有证明 HFOV 优于保护性常规机械通气（CV）。其中一个公认的解释是，CV 和 HFOV 的作用不同，包括气体交换。
为了研究 CV 和 HFOV 期间氧合和二氧化碳清除之间的不同程度的耦合或解耦，我们在 11 头健康猪中进行了一项前瞻性交叉动物研究。在每只动物中，我们在肺复张操作后发现了一个正常碳酸血症潮气量（V）。然后，在 CV 和 HFOV 期间保持 PEEP 水平恒定，在 HFOV 期间保持平均气道压力恒定的情况下，反复改变 V 的大小。记录动脉血氧分压（PO）和二氧化碳分压（PCO）。以随机顺序重复 CV 和 HFOV 的相同程序。
通过调整 V 故意引起的 PCO 变化在 HFOV 期间对氧合的影响比在 CV 期间更为显著。在 HFOV 期间将 V 增加到高于正常碳酸血症值会显著改善氧合，而 CV 过度通气时的氧合改善是有限的。在 HFOV 期间任何 V 的降低都会导致氧合迅速恶化，与 CV 相比。
由潮气量操作引起的 PCO 变化不可避免地会引起氧合的变化，而与 CV 相比，这种对氧合的影响在 HFOV 中更为显著。
