Bailes Stephanie A, Firestone Kimberly S, Dunn Diane K, McNinch Neil L, Brown Miraides F, Volsko Teresa A
Simulation Center of Safety and Reliability.
Neonatology Department.
Respir Care. 2016 Mar;61(3):333-9. doi: 10.4187/respcare.04251. Epub 2015 Nov 3.
Bubble CPAP, used for spontaneously breathing infants to avoid intubation or postextubation support, can be delivered with different interface types. This study compared the effect that interfaces had on CPAP delivery. We hypothesized that there would be no difference between set and measured levels between interface types.
A validated preterm infant nasal airway model was attached to the ASL 5000 breathing simulator. The simulator was programmed to deliver active breathing of a surfactant-deficient premature infant with breathing frequency at 70 breaths/min inspiratory time of 0.30 s, resistance of 150 cm H2O/L/s, compliance of 0.5 mL/cm H2O, tidal volume of 5 mL, and esophageal pressure of -10 cm H2O. Nasal CPAP prongs, size 4030, newborn and infant RAM cannulas were connected to a nasal airway model and a bubble CPAP system. CPAP levels were set at 4, 5, 6, 7, 8, and 9 cm H2O with flows of 6, 8, and 10 L/min each. Measurements were recorded after 1 min of stabilization. The analysis was performed using SAS 9.4. The Kolmogorov-Smirnov test assessed normality of the data. The Friedman test was used to compare non-normally distributed repeated measures. The Wilcoxon signed-rank test was used to conduct post hoc analysis. All tests were 2-sided, and P values of <.05 were considered as indicating significant differences unless otherwise indicated.
At lower set CPAP levels, 4-6 cm H2O, measured CPAP dropped precipitously with the nasal prongs with the highest flow setting. At higher CPAP levels, 7-9 cm H2O measured CPAP concomitantly increased as the flow setting increased. Statistically significant differences in set and measured CPAP occurred for all devices across all CPAP levels, with the measured CPAP less than set for all conditions, P < .001.
Set flow had a profound effect on measured CPAP. The concomitant drop in measured pressure with high and low flows could be attributed to increased resistance to spontaneous breathing or insufficient flow to meet inspiratory demand. Clinicians should be aware of the effect that the interface and flow have on CPAP delivery.
用于自主呼吸婴儿以避免插管或拔管后支持的气泡持续气道正压通气（Bubble CPAP），可通过不同的接口类型来提供。本研究比较了不同接口对持续气道正压通气输送的影响。我们假设不同接口类型之间设定水平和测量水平无差异。
将经过验证的早产儿鼻气道模型连接到ASL 5000呼吸模拟器上。对模拟器进行编程，使其模拟表面活性物质缺乏的早产儿的主动呼吸，呼吸频率为70次/分钟，吸气时间为0.30秒，阻力为150厘米水柱/升/秒，顺应性为0.5毫升/厘米水柱，潮气量为5毫升，食管压力为-10厘米水柱。将4030号鼻持续气道正压通气鼻塞、新生儿及婴儿RAM插管连接到鼻气道模型和气泡持续气道正压通气系统。持续气道正压通气水平设定为4、5、6、7、8和9厘米水柱，每种水平下的气流分别为6、8和10升/分钟。稳定1分钟后记录测量值。使用SAS 9.4进行分析。Kolmogorov-Smirnov检验评估数据的正态性。Friedman检验用于比较非正态分布的重复测量数据。Wilcoxon符号秩检验用于进行事后分析。所有检验均为双侧检验，除非另有说明，P值<.05被认为表明存在显著差异。
在较低的设定持续气道正压通气水平（4 - 6厘米水柱）时，使用最高气流设置的鼻鼻塞时，测量的持续气道正压通气急剧下降。在较高的持续气道正压通气水平（7 - 9厘米水柱）时，随着气流设置增加，测量的持续气道正压通气随之增加。在所有持续气道正压通气水平下，所有设备的设定和测量的持续气道正压通气均存在统计学显著差异，所有情况下测量的持续气道正压通气均低于设定值，P <.001。
设定气流对测量的持续气道正压通气有深远影响。高低气流下测量压力的相应下降可能归因于对自主呼吸的阻力增加或气流不足以满足吸气需求。临床医生应意识到接口和气流对持续气道正压通气输送的影响。
