Division of Neonatology, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania.
Department of Pediatrics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania.
Pediatr Pulmonol. 2019 Nov;54(11):1860-1865. doi: 10.1002/ppul.24459. Epub 2019 Jul 24.
This study describes the effect of high-frequency oscillation on airway pressure generated by high flow nasal cannula (HFNC) in a premature infant lung model.
DESIGN/METHODS: A premature in 0.5 or 1.0 mL/cmH O, respiratory rate (RR) of 40 or 60 breaths per min, and tidal volume of 6 mL. Oscillation was achieved by passing the HFNC supply flow through a 3-way solenoid valve operating at 4, 6, 8, or 10 Hz. Airway pressure at the simulated trachea was recorded following equilibration of end-tidal CO both with and without oscillation.
Superimposing high-frequency oscillations onto HFNC resulted in an average decrease in mean airway pressure of 17.9% (P = .011). The difference between the maximum and minimum airway pressures, ∆ P significantly increased as oscillation frequency decreased ( P < .001). Airway pressure during oscillation was 12.8% greater with the 1.0 vs the 0.5 mL/cmH O compliance at flows > 4 L/min ( P = .031). CO clearance was 13.1% greater with the 1.0 vs 0.5 mL/cmH O compliance at oscillation frequencies less than 8 Hz ( P = .015).
In this in-vitro study we demonstrate that delivered mean airway pressure decreases when applying high-frequency oscillation to HFNC, while still improving CO clearance. The combination of improved CO clearance and reduced pressure delivery of this novel noninvasive modality may prove to be a useful improvement in the respiratory care of infants in respiratory distress.
本研究描述高频振荡对高流量鼻导管（HFNC）在早产儿肺模型中产生的气道压力的影响。
方法/设计：在 0.5 或 1.0ml/cmH2O、呼吸频率（RR）为 40 或 60 次/分钟和潮气量为 6ml 的情况下，对早产儿进行研究。通过将 HFNC 供应流量通过操作频率为 4、6、8 或 10Hz 的三通电磁阀来实现振荡。在没有和有振荡的情况下，使呼气末 CO2 达到平衡后，记录模拟气管中的气道压力。
在 HFNC 上叠加高频振荡会导致平均气道压力平均降低 17.9%（P=0.011）。随着振荡频率的降低，最大和最小气道压力之间的差异，ΔP显著增加（P<0.001）。在流量大于 4L/min 时，1.0ml/cmH2O 顺应性比 0.5ml/cmH2O 顺应性的气道压力在振荡时高 12.8%（P=0.031）。在振荡频率小于 8Hz 时，1.0ml/cmH2O 顺应性比 0.5ml/cmH2O 顺应性的 CO2 清除率高 13.1%（P=0.015）。
在这项体外研究中，我们证明在 HFNC 上应用高频振荡会降低输送的平均气道压力，同时仍能提高 CO2 清除率。这种新型非侵入性治疗方式改善 CO2 清除率和降低压力输送的结合，可能会成为改善呼吸窘迫婴儿呼吸治疗的有用方法。
