Anesthesiology. 2021 May 1;134(5):748-759. doi: 10.1097/ALN.0000000000003736.
The lateral abdominal wall muscles are recruited with active expiration, as may occur with high breathing effort, inspiratory muscle weakness, or pulmonary hyperinflation. The effects of critical illness and mechanical ventilation on these muscles are unknown. This study aimed to assess the reproducibility of expiratory muscle (i.e., lateral abdominal wall muscles and rectus abdominis muscle) ultrasound and the impact of tidal volume on expiratory muscle thickness, to evaluate changes in expiratory muscle thickness during mechanical ventilation, and to compare this to changes in diaphragm thickness.
Two raters assessed the interrater and intrarater reproducibility of expiratory muscle ultrasound (n = 30) and the effect of delivered tidal volume on expiratory muscle thickness (n = 10). Changes in the thickness of the expiratory muscles and the diaphragm were assessed in 77 patients with at least two serial ultrasound measurements in the first week of mechanical ventilation.
The reproducibility of the measurements was excellent (interrater intraclass correlation coefficient: 0.994 [95% CI, 0.987 to 0.997]; intrarater intraclass correlation coefficient: 0.992 [95% CI, 0.957 to 0.998]). Expiratory muscle thickness decreased by 3.0 ± 1.7% (mean ± SD) with tidal volumes of 481 ± 64 ml (P < 0.001). The thickness of the expiratory muscles remained stable in 51 of 77 (66%), decreased in 17 of 77 (22%), and increased in 9 of 77 (12%) patients. Reduced thickness resulted from loss of muscular tissue, whereas increased thickness mainly resulted from increased interparietal fasciae thickness. Changes in thickness of the expiratory muscles were not associated with changes in the thickness of the diaphragm (R2 = 0.013; P = 0.332).
Thickness measurement of the expiratory muscles by ultrasound has excellent reproducibility. Changes in the thickness of the expiratory muscles occurred in 34% of patients and were unrelated to changes in diaphragm thickness. Increased expiratory muscle thickness resulted from increased thickness of the fasciae.
侧腹壁肌在主动呼气时被募集，这可能发生在高呼吸努力、吸气肌无力或肺过度充气时。危重病和机械通气对这些肌肉的影响尚不清楚。本研究旨在评估呼气肌（即侧腹壁肌和腹直肌）超声的可重复性，以及潮气量对呼气肌厚度的影响，评估机械通气过程中呼气肌厚度的变化，并将其与膈肌厚度的变化进行比较。
两名评估者评估呼气肌超声的组内和组间可重复性（n = 30），以及潮气量对呼气肌厚度的影响（n = 10）。在机械通气的第一周，对至少有两次连续超声测量的 77 名患者评估呼气肌和膈肌厚度的变化。
测量的可重复性非常好（组间组内相关系数：0.994 [95%置信区间，0.987 至 0.997]；组内组内相关系数：0.992 [95%置信区间，0.957 至 0.998]）。随着潮气量从 481 ± 64ml 增加，呼气肌厚度减少了 3.0 ± 1.7%（平均值 ± 标准差）（P < 0.001）。77 例患者中有 51 例（66%）呼气肌厚度保持稳定，17 例（22%）下降，9 例（12%）增加。厚度的减少是由于肌肉组织的丧失，而厚度的增加主要是由于间筋膜厚度的增加。呼气肌厚度的变化与膈肌厚度的变化无关（R2 = 0.013；P = 0.332）。
超声测量呼气肌厚度具有极好的可重复性。34%的患者呼气肌厚度发生变化，与膈肌厚度变化无关。呼气肌厚度的增加是由于筋膜厚度的增加。
