Recently, Wong et al. reported increased 28-day mortality among 328 children with pediatric acute respiratory distress syndrome (PARDS) managed with high-frequency oscillatory ventilation (HFOV) [1]. This study is an excellent example of gaining a better understanding of pediatric critical care through multicenter collaboration. Nonetheless, there are some nuances one should consider before interpreting the study results. Inherent to the study design, confounding by indication (i.e., the sickest patients are those most likely to receive a specific intervention) occurred albeit that the authors used advanced statistical techniques to address this. Furthermore, HFOV was largely employed as rescue without consistent criteria for its use and clinical management was done without a consistent protocol. Although HFOV has been available for several decades, we have no data demonstrating an optimal physiologic approach to HFOV management in the acute and weaning phase. Most pediatric HFOV papers make no mention of recruitment maneuvers (RMs) and reported frequencies (F) in the range of 5–8 Hz [2]. Yet, optimizing lung volume by means of a RM may be physiologically necessary to recruit collapsed, atelectatic lung units to improve oxygenation and prevent exposure to larger, potentially more injurious pressure swings [3]. Low F is not in line with the concept of the corner frequency (Fc) [4]. Fc is the F with the lowest pressure cost of ventilation and thus the least injurious to the lung. In disease conditions with reduced respiratory system compliance, such as PARDS, Fc is increased indicating that the highest oscillatory F that still allows for adequate ventilation might be preferable. Also, there are no data guiding the HFOV weaning process, possibly explaining the observed increased ventilation times seen in patients managed with the oscillator [5]. We are now enrolling pediatric patients in the Prone and Oscillation Pediatric Clinical Trial (PROSpect) to address the issue surrounding the uncertainty regarding the role and optimal management of HFOV for PARDS. In this adaptive randomized control trial, patients with high moderate-to-severe PARDS (OI > 12) are randomized to test the hypothesis that prone versus supine positioning and HFOV versus conventional mechanical ventilation (CMV) will result in a 2-day improvement in ventilator-free days. In this trial, CMV and HFOV are strictly protocolized, and the HFOV protocol makes use of staircase RMs, high F, and daily titration to improve the weaning process. From our perspective, until we have the results of this RCT, there is therefore no need to abandon HFOV.

中文翻译：

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PARDS 的高频振荡通气：等待 PROSPect

最近，Wong 等人。据报道，328 名儿童急性呼吸窘迫综合征 (PARDS) 使用高频振荡通气 (HFOV) 治疗后 28 天死亡率增加 [1]。这项研究是通过多中心合作更好地了解儿科重症监护的一个很好的例子。尽管如此，在解释研究结果之前，应该考虑一些细微差别。尽管作者使用了先进的统计技术来解决这个问题，但研究设计固有的混淆（即，病情最严重的患者是最有可能接受特定干预的患者）。此外，HFOV 主要用作救援，但没有一致的使用标准，临床管理也没有一致的协议。尽管 HFOV 已经可用了几十年，但我们没有数据证明急性期和断奶期 HFOV 管理的最佳生理方法。大多数儿科 HFOV 论文都没有提到复张操作 (RM) 和 5-8 Hz 范围内的频率 (F) [2]。然而，通过 RM 优化肺容量可能在生理上是必要的，以募集塌陷、肺不张的肺单位以改善氧合并防止暴露于更大、可能更有害的压力波动 [3]。低 F 不符合转角频率 (Fc) [4] 的概念。Fc 是通气压力成本最低的 F，因此对肺的伤害最小。在呼吸系统顺应性降低的疾病情况下，例如 PARDS，Fc 增加表明仍然允许足够通风的最高振荡 F 可能是可取的。此外，没有数据指导 HFOV 撤机过程，这可能解释了在使用振荡器管理的患者中观察到的通气时间增加 [5]。我们现在正在招募儿科患者参加俯卧和摆动儿科临床试验 (PROSpect)，以解决围绕 HFOV 对 PARDS 的作用和最佳管理的不确定性的问题。在这项适应性随机对照试验中，高度中度至重度 PARDS（OI > 12）的患者被随机化以测试俯卧位与仰卧位以及 HFOV 与传统机械通气 (CMV) 将导致 2 天改善的假设无呼吸机天数。在这个试验中，CMV 和 HFOV 是严格的协议化，HFOV 协议利用阶梯 RMs、高 F 和每日滴定来改进断奶过程。从我们的角度来看，在获得本 RCT 的结果之前，没有必要放弃 HFOV。