Neonatal Intensive Care Centre, King's College Hospital NHS Foundation Trust, London, United Kingdom.
Women and Children's Health, School of Life Course Sciences, Faculty of Life Sciences and Medicine, King's College London, London, United Kingdom.
Respir Care. 2019 Mar;64(3):285-291. doi: 10.4187/respcare.06354. Epub 2018 Nov 6.
CPAP improves respiratory function in prematurely born infants by establishing and maintaining functional residual capacity, but the level of CPAP that optimizes respiratory function has not been adequately described. We compared ventilation efficiency and respiratory muscle function at different levels of CPAP.
We studied spontaneously breathing, intubated convalescent premature infants at King's College Hospital NHS Foundation Trust and calculated the ventilation efficiency index and the respiratory muscle time constant of relaxation (τ) at the end of 3 consecutive 5-min periods at 4, 6, and 8 cm HO of CPAP delivered in random order.
Between February 2016 and August 2016, 38 infants with a median gestational age of 27 (interquartile range [IQR], 25-30) weeks and a median birthweight of 0.88 (IQR, 0.73-1.02) kg were studied. At a CPAP level of 6 cm HO, the median ventilation efficiency index was higher (1.52 [IQR, 1.02-2.27]) and median τ was lower (15.6 [IQR, 10.1-21.3]) s/cm HO] compared with the median ventilation efficiency index (0.75 [IQR, 0.56-1.03]) and median τ (23.3 [IQR, 15.4-35.2] sec/cm HO) at CPAP of 4 cm HO ( < .001 for both). At a CPAP level of 8 cm HO, median ventilation efficiency index was significantly lower (1.27 [IQR, 1.04-1.91]) and median τ was not significantly different (11.2 [IQR, 8.3-18.9] s/cm HO) compared with ventilation efficiency index and τ at CPAP of 6 cm HO ( < .001 and = .12, respectively). After multiple logistic regression, the level of CPAP was independently associated with the ventilation efficiency index (adjusted < .001) and τ (adjusted = .003).
Increasing the level of CPAP from 4 to 6 cm HO was associated with enhanced ventilation efficiency and respiratory muscle function in convalescent premature infants on ventilation, but there was no further benefit from increasing the pressure >6 cm HO.
CPAP 通过建立和维持功能残气量来改善早产儿的呼吸功能，但优化呼吸功能的 CPAP 水平尚未得到充分描述。我们比较了不同 CPAP 水平下的通气效率和呼吸肌功能。
我们在 King's College Hospital NHS Foundation Trust 研究了自主呼吸、插管恢复期的早产儿，并在随机顺序下连续 3 个 5 分钟周期的结束时计算了 CPAP 为 4、6 和 8 cm H2O 时的通气效率指数和呼吸肌松弛时间常数（τ）。
2016 年 2 月至 2016 年 8 月，研究了 38 名中位胎龄为 27（四分位距[IQR]，25-30）周、中位出生体重为 0.88（IQR，0.73-1.02）kg 的婴儿。在 CPAP 水平为 6 cm HO 时，通气效率指数中位数较高（1.52[IQR，1.02-2.27]），τ 中位数较低（15.6[IQR，10.1-21.3]）s/cm HO]与 CPAP 为 4 cm HO 时的通气效率指数中位数（0.75[IQR，0.56-1.03]）和τ 中位数（23.3[IQR，15.4-35.2] sec/cm HO]相比（均<.001）。CPAP 水平为 8 cm HO 时，通气效率指数中位数显著降低（1.27[IQR，1.04-1.91]），τ 中位数差异无统计学意义（11.2[IQR，8.3-18.9] s/cm HO）与 CPAP 为 6 cm HO 时的通气效率指数和 τ（均<.001 和=0.12）。多因素逻辑回归后，CPAP 水平与通气效率指数（校正<.001）和 τ（校正=0.003）独立相关。
在接受通气的恢复期早产儿中，CPAP 水平从 4 增加到 6 cm HO 与通气效率和呼吸肌功能增强相关，但增加压力>6 cm HO 没有进一步的益处。
