Larouche Alexandrine, Massicotte Erika, Constantin Gabrielle, Ducharme-Crevier Laurence, Essouri Sandrine, Sinderby Christer, Beck Jennifer, Emeriaud Guillaume
Pediatric Intensive Care Unit, CHU Sainte-Justine, Université de Montréal, Montreal, Quebec, Canada.
Pediatric Intensive Care Unit, CHU Kremlin Bicêtre, Université Paris Sud, Le Kremlin Bicêtre, France.
Pediatr Pulmonol. 2015 Dec;50(12):1304-12. doi: 10.1002/ppul.23182. Epub 2015 May 4.
Infants have to actively maintain their end expiratory lung volume (EELV). In mechanically ventilated infants, the diaphragm stays activated until the end of expiration (tonic activity), contributing to EELV maintenance. It is unclear whether tonic activity compensates for the lack of laryngeal braking due to intubation or if it is normally present.
To determine if tonic diaphragm activity remains after extubation in infants, and if it can be observed in older children.
Prospective observational study of pediatric patients ventilated for >24 hr. Diaphragm electrical activity (EAdi) was recorded using a specific nasogastric catheter during four periods: (i) the acute phase, (ii) pre-extubation, (iii) post-extubation, and (iv) at PICU discharge. Tonic EAdi was defined as the EAdi in the last quartile of expiration.
Fifty-five patients, median age 10 months (Interquartile range: 1-48) were studied. In infants (<1 year, n = 28), tonic EAdi was always present, and represented 33% (22-43) of inspiratory EAdi at PICU discharge. No significant change was observed between pre- and post-extubation periods. In older patients (n = 27), tonic activity was negligible as a whole, but 10 patients exhibited significant tonic EAdi at one time-point during PICU stay. Bronchiolitis was the only independent factor associated with tonic EAdi.
In infants, tonic EAdi remains involved in ventilatory control after extubation and restoration of laryngeal braking. Tonic EAdi may play a pathophysiological role in bronchiolitis and it can be reactivated in older patients. The interest of tonic EAdi as a tool to titrate mechanical ventilation warrants further evaluation.
婴儿必须主动维持其呼气末肺容积（EELV）。在机械通气的婴儿中，膈肌在呼气结束前一直保持激活状态（紧张性活动），有助于维持EELV。目前尚不清楚紧张性活动是弥补了因插管导致的喉部制动缺失，还是其原本就存在。
确定婴儿拔管后紧张性膈肌活动是否依然存在，以及在大龄儿童中是否能观察到这种活动。
对通气时间超过24小时的儿科患者进行前瞻性观察研究。在四个阶段使用特定的鼻胃管记录膈肌电活动（EAdi）：（i）急性期，（ii）拔管前，（iii）拔管后，以及（iv）在儿科重症监护病房（PICU）出院时。紧张性EAdi定义为呼气最后四分位数期间的EAdi。
共研究了55例患者，中位年龄10个月（四分位间距：1 - 48个月）。在婴儿（<1岁，n = 28）中，紧张性EAdi始终存在，在PICU出院时占吸气EAdi的33%（22 - 43）。拔管前后未观察到显著变化。在大龄患者（n = 27）中，总体紧张性活动可忽略不计，但有10例患者在PICU住院期间的某个时间点表现出显著的紧张性EAdi。细支气管炎是与紧张性EAdi相关的唯一独立因素。
在婴儿中，紧张性EAdi在拔管和喉部制动恢复后仍参与通气控制。紧张性EAdi可能在细支气管炎中发挥病理生理作用，并且在大龄患者中可被重新激活。紧张性EAdi作为调整机械通气的工具的价值值得进一步评估。
