Formenti Paolo, Miori Sara, Galimberti Andrea, Umbrello Michele
SC Anestesia e Rianimazione I, ASST Santi Paolo e Carlo-Polo Universitario, Ospedale San Paolo, 20142 Milan, Italy.
SC Anestesia e Rianimazione I, Ospedale Santa Chiara, APSS, 30014 Trento, Italy.
Diagnostics (Basel). 2023 Mar 17;13(6):1157. doi: 10.3390/diagnostics13061157.
: Diaphragm dysfunction is common in patients undergoing mechanical ventilation. The application of positive end-expiratory pressure (PEEP) and the varying end-expiratory lung volume cause changes in diaphragm geometry. We aimed to assess the impact of the level of PEEP and lung inflation on diaphragm thickness, thickening fraction and displacement. : An observational study in a mixed medical and surgical ICU was conducted. The patients underwent a PEEP-titration trial with the application of three random levels of PEEP: 0 cmHO (PEEP0), 8 cmHO (PEEP8) and 15 cmHO (PEEP15). At each step, the indices of respiratory effort were assessed, together with arterial blood and diaphragm ultrasound; end-expiratory lung volume was measured. : 14 patients were enrolled. The tidal volume, diaphragm displacement and thickening fraction were significantly lower with higher levels of PEEP, while both the expiratory and inspiratory thickness increased with higher PEEP levels. The inspiratory effort, as evaluated by the esophageal pressure swing, was unchanged. Both the diaphragm thickening fraction and displacement were significantly correlated with inspiratory effort in the whole dataset. For both measurements, the correlation was stronger at lower levels of PEEP. The difference in the diaphragm thickening fraction during tidal breathing between PEEP 15 and PEEP 0 was negatively related to the change in the functional residual capacity and the change in alveolar dead space. : Different levels of PEEP significantly modified the diaphragmatic thickness and thickening fraction, showing a PEEP-induced decrease in the diaphragm contractile efficiency. When using ultrasound to assess diaphragm size and function, the potential effect of lung inflation should be taken into account.
膈肌功能障碍在接受机械通气的患者中很常见。呼气末正压（PEEP）的应用以及呼气末肺容积的变化会导致膈肌形态改变。我们旨在评估PEEP水平和肺充气对膈肌厚度、增厚分数和位移的影响。
在一所综合内科和外科重症监护病房进行了一项观察性研究。患者接受了PEEP滴定试验，应用了三个随机的PEEP水平：0 cmH₂O（PEEP0）、8 cmH₂O（PEEP8）和15 cmH₂O（PEEP15）。在每个步骤中，评估呼吸努力指标，同时进行动脉血气分析和膈肌超声检查；测量呼气末肺容积。
共纳入14例患者。较高水平的PEEP时，潮气量、膈肌位移和增厚分数显著降低，而呼气和吸气时的膈肌厚度均随PEEP水平升高而增加。通过食管压力波动评估的吸气努力没有变化。在整个数据集中，膈肌增厚分数和位移均与吸气努力显著相关。对于这两项测量，在较低的PEEP水平时相关性更强。PEEP 15和PEEP 0时潮气呼吸期间膈肌增厚分数的差异与功能残气量的变化和肺泡死腔的变化呈负相关。
不同水平的PEEP显著改变了膈肌厚度和增厚分数，表明PEEP导致膈肌收缩效率降低。在使用超声评估膈肌大小和功能时，应考虑肺充气的潜在影响。
