Emeriaud Guillaume, Beck Jennifer, Tucci Marisa, Lacroix Jacques, Sinderby Christer
Department of Pediatrics, Hôpital Sainte-Justine, Quebec, Canada, H3T 1C5.
Pediatr Res. 2006 May;59(5):705-10. doi: 10.1203/01.pdr.0000214986.82862.57.
The presence of diaphragm electrical activity (EAdi) during expiration is believed to be involved in the maintenance of end-expiratory lung volume (EELV) and has never been studied in intubated and mechanically ventilated infants. The aim of this study was to quantify the amplitude of diaphragm electrical activity present during expiration in mechanically ventilated infants and to measure the impact of removing positive end-expiratory pressure (PEEP) on this activity. We studied the EAdi in 16 ready-to-be weaned intubated infants who were breathing on their prescribed ventilator and PEEP settings. In all 16 patients, 5 min of data were collected on the prescribed ventilator settings. In a subset of eight patients, the PEEP was briefly reduced to zero PEEP (ZEEP). EAdi was recorded with miniaturized sensors placed on a conventional nasogastric feeding tube. Airway pressure (Paw) was also measured. For each spontaneous breath, we identified the neural inspiration and neural expiration. Neural expiration was divided into quartiles (Q1, Q2, Q3, and Q4), and the amplitude of EAdi calculated for each Q1-Q4 represented 95 +/- 29%, 31 +/- 15%, 15 +/- 8%, and 12 +/- 7%, respectively, of the inspiratory EAdi amplitude. EAdi for Q3-Q4 significantly increased during ZEEP, and decreased after reapplication of PEEP. These findings confirm that the diaphragm remains partially active during expiration in intubated and mechanically ventilated infants and that removal of PEEP affects this tonic activity. This could have potential implications on the management of PEEP in intubated infants.
呼气时膈肌电活动（EAdi）的存在被认为与呼气末肺容积（EELV）的维持有关，且从未在插管并机械通气的婴儿中进行过研究。本研究的目的是量化机械通气婴儿呼气时膈肌电活动的幅度，并测量去除呼气末正压（PEEP）对该活动的影响。我们研究了16名准备撤机的插管婴儿，这些婴儿按照规定的呼吸机设置和PEEP进行呼吸。在所有16名患者中，按照规定的呼吸机设置收集了5分钟的数据。在8名患者的子集中，将PEEP短暂降至零PEEP（ZEEP）。使用放置在传统鼻胃饲管上的小型传感器记录EAdi。还测量了气道压力（Paw）。对于每一次自主呼吸，我们确定了神经吸气和神经呼气。神经呼气被分为四分位数（Q1、Q2、Q3和Q4），每个Q1-Q4的EAdi幅度分别占吸气EAdi幅度的95±29%、31±15%、15±8%和12±7%。在ZEEP期间，Q3-Q4的EAdi显著增加，重新应用PEEP后降低。这些发现证实，在插管并机械通气的婴儿中，呼气时膈肌仍部分活跃，且去除PEEP会影响这种张力性活动。这可能对插管婴儿的PEEP管理有潜在影响。
