CHOP Newborn Care at Pennsylvania Hospital, Philadelphia, Pennsylvania.
Division of Neonatology, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania.
Pediatr Pulmonol. 2019 Apr;54(4):436-443. doi: 10.1002/ppul.24216. Epub 2018 Dec 14.
This study compared CO clearance in a premature infant lung model connected to a high flow nasal cannula (HFNC) system supplied with oscillatory versus non-oscillatory flow.
DESIGN/METHODS: The lung model was set to compliance 1.0 mL/cmH O, RR 60 breaths/min, and 6 mL tidal volume. A 100% CO was injected at a constant 15 mL/min. To create oscillation, HFNC flow was interrupted at rates of 4-6-8 and 10 Hz. equilibrated end-tidal CO (ETCO ) was recorded with and without oscillation at set flows of 2-8 L/min and repeated for each oscillation frequency.
Overall ETCO decreased significantly (P < 0.001) during both non-oscillatory and oscillatory HFNC as set flow increased from 2 to 8 L/min by 26.3% and 60.8%, respectively. Oscillatory ETCO levels decreased linearly compared to non-oscillatory HFNC with negligible difference at 2 L/min and a 48.4% difference at 8 L/min (P < 0.001). There were no differences in ETCO levels between oscillation frequencies at any flow except at 6 Hz for which ETCO was significantly lower (P < 0.01) than at 4, 8, and 10 Hz for 5-8 L/min HFNC flows. Amplitude of volume oscillations increased with increasing flow from 0.5 mL at 2 L/min to 4.0 mL at 8 L/min (P < 0.001), and decreased with increasing oscillation frequency.
Oscillatory HFNC as compared to non-oscillatory was associated with significantly improved CO clearance in this premature infant lung model. This simple modification of the HFNC system may prove to be a useful enhancement to this mode of non-invasive respiratory support for preterm infants at high risk for respiratory failure.
本研究比较了在连接高流量鼻导管（HFNC）系统的早产儿肺模型中，使用振荡和非振荡气流时 CO 的清除率。
方法/设计：将肺模型设置为顺应性 1.0 mL/cmH 2 O、RR 每分钟 60 次呼吸和 6 mL 潮气量。以 15 mL/min 的恒定速度注入 100% CO。为了产生振荡，HFNC 气流以 4-6-8 和 10 Hz 的速率中断。在设定流速为 2-8 L/min 时，记录有和没有振荡时的平衡呼气末 CO（ETCO），并为每个振荡频率重复记录。
在设定流速从 2 增加到 8 L/min 时，非振荡和振荡 HFNC 期间的 ETCO 均显著降低（P < 0.001），分别降低了 26.3%和 60.8%。与非振荡 HFNC 相比，振荡 ETCO 水平呈线性下降，在 2 L/min 时差异可以忽略不计，而在 8 L/min 时差异为 48.4%（P < 0.001）。除了在 6 Hz 时 ETCO 明显更低（P < 0.01）外，在任何流速下，振荡频率之间的 ETCO 水平均无差异，在 5-8 L/min HFNC 流速下，ETCO 水平明显低于 4、8 和 10 Hz。体积振荡的幅度随着流速的增加而增加，从 2 L/min 的 0.5 mL 增加到 8 L/min 的 4.0 mL（P < 0.001），并且随着振荡频率的增加而降低。
与非振荡 HFNC 相比，这种早产儿肺模型中振荡 HFNC 与 CO 清除率显著提高相关。HFNC 系统的这种简单改进可能会成为高危呼吸衰竭早产儿的这种非侵入性呼吸支持模式的有用增强。
