Section of Pulmonary and Critical Care Medicine, Department of Medicine, University of Chicago, Chicago, Illinois.
Department of Pulmonary Medicine, University of Texas MD Anderson Cancer Center, Houston, Texas; and.
Ann Am Thorac Soc. 2022 Sep;19(9):1543-1550. doi: 10.1513/AnnalsATS.202111-1280OC.
In patients who are mechanically ventilated, diaphragm thinning on ultrasound is thought to correlate with diaphragm atrophy and has been associated with prolonged intubation. Factors other than atrophy, however, may cause changes in diaphragm thickness, which may confound studies examining changes in diaphragm thickness over time. To determine if changes in the mode of mechanical ventilation or an interruption of sedatives have immediate effects on diaphragm thickness measurements in adult patients in the intensive care unit who are mechanically ventilated. Adult patients receiving invasive mechanical ventilation for less than 48 hours were included. Diaphragm thickness was measured at end-expiration and peak inspiration using ultrasound while patients were receiving both volume assist-control and pressure-support modes in a randomized crossover fashion. In patients receiving sedatives, additional measurements were taken after an interruption of sedatives. Measurements were compared between modes and on assist-control before and after an interruption of sedatives. Of 85 patients enrolled, 66 had measurements on assist-control and spontaneous modes, and 40 had measurements before and after an interruption of sedatives. End-expiratory diaphragm thickness increased by a median of 0.08 mm after an interruption of sedatives (95% confidence interval [CI], 0.002 mm to 0.164 mm; = 0.017), corresponding to a median increase of 6.5%. No difference was seen when comparing measurements taken on volume assist-control and pressure support (median difference, 0 mm; 95% CI, -0.07 mm to 0.08 mm; = 0.98). End-expiratory diaphragm thickness increased by 6.5% after an interruption of sedatives. The effect of sedatives on measured diaphragm thickness should be considered in future studies examining changes in diaphragm thickness over time. Clinical trial registered with Clinicaltrials.gov (NCT04319939).
在接受机械通气的患者中，超声检查发现的膈肌变薄被认为与膈肌萎缩有关，并与长时间插管有关。然而，除了萎缩之外，其他因素也可能导致膈肌厚度发生变化，这可能会混淆研究中随着时间的推移观察膈肌厚度变化的结果。为了确定在接受机械通气的重症监护病房成年患者中，机械通气模式的改变或镇静剂的中断是否会对膈肌厚度测量值产生即时影响。
纳入接受机械通气时间少于 48 小时的成年患者。在患者接受容量辅助控制和压力支持模式的随机交叉方式时，使用超声在呼气末和吸气峰时测量膈肌厚度。在接受镇静剂的患者中，在镇静剂中断后进行额外的测量。在模式之间以及在镇静剂中断前后的辅助控制模式下比较测量值。
在纳入的 85 名患者中，有 66 名患者在辅助控制和自主通气模式下进行了测量，有 40 名患者在镇静剂中断前后进行了测量。镇静剂中断后，膈肌厚度在呼气末增加了中位数 0.08 毫米（95%置信区间 [CI]，0.002 毫米至 0.164 毫米； = 0.017），中位数增加了 6.5%。在比较容量辅助控制和压力支持时，测量值没有差异（中位数差值 0 毫米；95% CI，-0.07 毫米至 0.08 毫米； = 0.98）。
镇静剂中断后，膈肌厚度增加了 6.5%。在未来研究中，应该考虑镇静剂对测量膈肌厚度的影响，这些研究旨在研究随着时间的推移膈肌厚度的变化。该临床试验已在 ClinicalTrials.gov 注册（NCT04319939）。
