Neuromuscular Physiology Laboratory, Neuromuscular Investigation Center, Institute of Myology , Paris , France.
Service de Pneumologie, Médecine Intensive et Réanimation (Département "R3S"), Groupe Hospitalier Pitié-Salpêtrière Charles Foix, Assistance Publique-Hôpitaux de Paris, Paris , France.
J Appl Physiol (1985). 2019 Mar 1;126(3):699-707. doi: 10.1152/japplphysiol.01060.2018. Epub 2019 Feb 7.
The reference method for the assessment of diaphragm function relies on the measurement of transdiaphragmatic pressure (Pdi). Local muscle stiffness measured using ultrafast shear wave elastography (SWE) provides reliable estimates of muscle force in locomotor muscles. This study aimed at investigating whether SWE could be used as a surrogate of Pdi to evaluate diaphragm function. Fifteen healthy volunteers underwent a randomized stepwise inspiratory loading protocol of 0-60% of maximal isovolumetric inspiratory pressure during closed-airways maneuvers and 0-50% during ventilation against an external inspiratory threshold load. During all tasks, Pdi was measured and SWE was used to assess shear modulus of the right hemidiaphragm (SMdi) at the zone of apposition. Pearson correlation coefficients ( r) and repeated-measures correlation coefficients ( R) were computed to determine within-individual and overall relationships between Pdi and SMdi, respectively. During closed-airways maneuvers, mean Pdi correlated to mean SMdi in all participants [ r ranged from 0.77 to 0.96, all P < 0.01; R = 0.82, 95% confidence intervals (0.76, 0.86), P < 0.01]. During ventilation against inspiratory threshold loading, Pdi swing correlated to maximal SMdi in all participants [ r ranged from 0.40 to 0.90, all P < 0.01; R = 0.70, 95% confidence intervals (0.66, 0.73), P < 0.001]. Changes in diaphragm stiffness as assessed by SWE reflect changes in transdiaphragmatic pressure. SWE provides a new opportunity for direct and noninvasive assessment of diaphragm function. NEW & NOTEWORTHY Accurate and specific estimation of diaphragm effort is critical for evaluating and monitoring diaphragm dysfunction. The measurement of transdiaphragmatic pressure requires the use of invasive gastric and esophageal probes. In the present work, we demonstrate that changes in diaphragm stiffness assessed with ultrasound shear wave elastography reflect changes in transdiaphragmatic pressure, therefore offering a new noninvasive method for gauging diaphragm effort.
膈肌功能评估的参考方法依赖于跨膈压（Pdi）的测量。使用超快剪切波弹性成像（SWE）测量的局部肌肉僵硬度可可靠估计运动肌肉的肌肉力量。本研究旨在探讨 SWE 是否可作为 Pdi 的替代物来评估膈肌功能。15 名健康志愿者在闭合气道操作期间接受了逐步递增的吸气负荷方案（0-60%最大等容吸气压力）和通气期间接受了 0-50%的吸气外阈负荷，0-50%。在所有任务中，均测量了 Pdi，并使用 SWE 评估了附着区右侧横膈膜的剪切模量（SMdi）。计算了个体内和总体之间 Pdi 和 SMdi 之间的 Pearson 相关系数（r）和重复测量相关系数（R）。在闭合气道操作期间，所有参与者的平均 Pdi 与平均 SMdi 相关[ r 范围为 0.77 至 0.96，均 P < 0.01；R = 0.82，95%置信区间（0.76，0.86），P < 0.01]。在对抗吸气阈负荷通气期间，所有参与者的 Pdi 摆动与最大 SMdi 相关[r 范围为 0.40 至 0.90，均 P < 0.01；R = 0.70，95%置信区间（0.66，0.73），P < 0.001]。SWE 评估的膈肌僵硬度变化反映了跨膈压的变化。SWE 为直接和无创评估膈肌功能提供了新的机会。创新性和重要性 准确和具体地估计膈肌的努力对于评估和监测膈肌功能障碍至关重要。跨膈压的测量需要使用侵入性胃和食管探头。在本工作中，我们证明了超声剪切波弹性成像评估的膈肌僵硬度变化反映了跨膈压的变化，因此提供了一种新的无创方法来衡量膈肌的努力。
