Roesthuis L H, van der Hoeven J G, van Hees H W H, Schellekens W-J M, Doorduin J, Heunks L M A
Department of Intensive Care Medicine, Radboud University Medical Center, Nijmegen, The Netherlands.
Department of Pulmonary Diseases, Radboud University Medical Center, Nijmegen, The Netherlands.
Ann Intensive Care. 2020 May 29;10(1):67. doi: 10.1186/s13613-020-00684-6.
Inappropriate ventilator assist plays an important role in the development of diaphragm dysfunction. Ventilator under-assist may lead to muscle injury, while over-assist may result in muscle atrophy. This provides a good rationale to monitor respiratory drive in ventilated patients. Respiratory drive can be monitored by a nasogastric catheter, either with esophageal balloon to determine muscular pressure (gold standard) or with electrodes to measure electrical activity of the diaphragm. A disadvantage is that both techniques are invasive. Therefore, it is interesting to investigate the role of surrogate markers for respiratory dive, such as extradiaphragmatic inspiratory muscle activity. The aim of the current study was to investigate the effect of different inspiratory support levels on the recruitment pattern of extradiaphragmatic inspiratory muscles with respect to the diaphragm and to evaluate agreement between activity of extradiaphragmatic inspiratory muscles and the diaphragm.
Activity from the alae nasi, genioglossus, scalene, sternocleidomastoid and parasternal intercostals was recorded using surface electrodes. Electrical activity of the diaphragm was measured using a multi-electrode nasogastric catheter. Pressure support (PS) levels were reduced from 15 to 3 cmHO every 5 min with steps of 3 cmHO. The magnitude and timing of respiratory muscle activity were assessed.
We included 17 ventilated patients. Diaphragm and extradiaphragmatic inspiratory muscle activity increased in response to lower PS levels (36 ± 6% increase for the diaphragm, 30 ± 6% parasternal intercostals, 41 ± 6% scalene, 40 ± 8% sternocleidomastoid, 43 ± 6% alae nasi and 30 ± 6% genioglossus). Changes in diaphragm activity correlated best with changes in alae nasi activity (r = 0.49; P < 0.001), while there was no correlation between diaphragm and sternocleidomastoid activity. The agreement between diaphragm and extradiaphragmatic inspiratory muscle activity was low due to a high individual variability. Onset of alae nasi activity preceded the onset of all other muscles.
Extradiaphragmatic inspiratory muscle activity increases in response to lower inspiratory support levels. However, there is a poor correlation and agreement with the change in diaphragm activity, limiting the use of surface electromyography (EMG) recordings of extradiaphragmatic inspiratory muscles as a surrogate for electrical activity of the diaphragm.
不适当的通气辅助在膈肌功能障碍的发生发展中起重要作用。通气不足可能导致肌肉损伤，而过度辅助可能导致肌肉萎缩。这为监测机械通气患者的呼吸驱动提供了充分的理论依据。呼吸驱动可通过鼻胃管进行监测，可使用食管气囊测定肌肉压力（金标准）或使用电极测量膈肌的电活动。缺点是这两种技术都具有侵入性。因此，研究呼吸驱动替代标志物的作用很有意义，比如膈外吸气肌活动。本研究的目的是探讨不同吸气支持水平对膈外吸气肌相对于膈肌的募集模式的影响，并评估膈外吸气肌与膈肌活动之间的一致性。
使用表面电极记录鼻翼、颏舌肌、斜角肌、胸锁乳突肌和胸骨旁肋间肌的活动。使用多电极鼻胃管测量膈肌的电活动。压力支持（PS）水平以3 cmH₂O为步长，每5分钟从15 cmH₂O降至3 cmH₂O。评估呼吸肌活动的幅度和时间。
我们纳入了17例机械通气患者。随着PS水平降低，膈肌和膈外吸气肌活动增加（膈肌增加36±6%，胸骨旁肋间肌增加30±6%，斜角肌增加41±6%，胸锁乳突肌增加40±8%，鼻翼增加43±6%，颏舌肌增加30±6%）。膈肌活动的变化与鼻翼活动的变化相关性最好（r = 0.49；P < 0.001），而膈肌与胸锁乳突肌活动之间无相关性。由于个体差异较大，膈肌与膈外吸气肌活动之间的一致性较低。鼻翼活动的起始先于所有其他肌肉。
膈外吸气肌活动随着吸气支持水平降低而增加。然而，与膈肌活动的变化相关性和一致性较差，限制了将膈外吸气肌的表面肌电图（EMG）记录用作膈肌电活动替代指标的应用。
