Respiratory Physiology Laboratory, Department of Neurology, Institute for Translational Neurology, University Hospital Münster, Münster, Germany,
Institute of Life Sciences, Scuola Superiore Sant´Anna, Pisa, Italy,
Respiration. 2020;99(5):369-381. doi: 10.1159/000506016. Epub 2020 May 12.
Reference values derived from existing diaphragm ultrasound protocols are inconsistent, and the association between sonographic measures of diaphragm function and volitional tests of respiratory muscle strength is still ambiguous.
To propose a standardized and comprehensive protocol for diaphragm ultrasound in order to determine lower limits of normal (LLN) for both diaphragm excursion and thickness in healthy subjects and to explore the association between volitional tests of respiratory muscle strength and diaphragm ultrasound parameters.
Seventy healthy adult subjects (25 men, 45 women; age 34 ± 13 years) underwent spirometric lung function testing, determination of maximal inspiratory and expiratory pressure along with ultrasound evaluation of diaphragm excursion and thickness during tidal breathing, deep breathing, and maximum voluntary sniff. Excursion data were collected for amplitude and velocity of diaphragm displacement. Diaphragm thickness was measured in the zone of apposition at total lung capacity (TLC) and functional residual capacity (FRC). All participants underwent invasive measurement of transdiaphragmatic pressure (Pdi) during different voluntary breathing maneuvers.
Ultrasound data were successfully obtained in all participants (procedure duration 12 ± 3 min). LLNs (defined as the 5th percentile) for diaphragm excursion were as follows: (a) during tidal breathing: 1.2 cm (males; M) and 1.2 cm (females; F) for amplitude, and 0.8 cm/s (M) and 0.8 cm/s (F) for velocity, (b) during maximum voluntary sniff: 2.0 cm (M) and 1.5 cm (F) for amplitude, and 6.7 (M) cm/s and 5.2 cm/s (F) for velocity, and (c) at TLC: 7.9 cm (M) and 6.4 cm (F) for amplitude. LLN for diaphragm thickness was 0.17 cm (M) and 0.15 cm (F) at FRC, and 0.46 cm (M) and 0.35 cm (F) at TLC. Values for males were consistently higher than for females, independent of age. LLN for diaphragmatic thickening ratio was 2.2 with no difference between genders. LLN for invasively measured Pdi during different breathing maneuvers are presented. Voluntary Pdi showed only weak correlation with both diaphragm excursion velocity and amplitude during forced inspiration.
Diaphragm ultrasound is an easy-to-perform and reproducible diagnostic tool for noninvasive assessment of diaphragm excursion and thickness. It supplements but does not replace respiratory muscle strength testing.
现有膈肌超声协议得出的参考值不一致，膈肌功能的超声测量与呼吸肌力量的随意测试之间的关联仍不明确。
提出一种标准化和全面的膈肌超声协议，以确定健康受试者膈肌活动度和厚度的下限正常值（LLN），并探讨呼吸肌力量的随意测试与膈肌超声参数之间的关系。
70 名健康成年受试者（25 名男性，45 名女性；年龄 34±13 岁）接受了肺功能通气检查、最大吸气和呼气压力的测定，以及在潮式呼吸、深吸气和最大自主吸气时进行膈肌活动度和厚度的超声评估。活动度数据用于测量膈肌位移的幅度和速度。在总肺容量（TLC）和功能残气量（FRC）时测量膈肌厚度。所有参与者在不同的自主呼吸动作期间接受了膈肌跨膈压（Pdi）的有创测量。
所有参与者均成功获得了超声数据（程序持续时间 12±3 分钟）。膈肌活动度的 LLN（定义为第 5 个百分位数）如下：（a）在潮式呼吸时：幅度为 1.2cm（男性；M）和 1.2cm（女性；F），速度为 0.8cm/s（M）和 0.8cm/s（F）；（b）在最大自主吸气时：幅度为 2.0cm（M）和 1.5cm（F），速度为 6.7cm/s（M）和 5.2cm/s（F）；（c）在 TLC 时：幅度为 7.9cm（M）和 6.4cm（F）。膈肌厚度的 LLN 在 FRC 时为 0.17cm（M）和 0.15cm（F），在 TLC 时为 0.46cm（M）和 0.35cm（F）。男性的值始终高于女性，与年龄无关。膈肌增厚率的 LLN 为 2.2，性别之间无差异。不同呼吸动作时的有创测量 Pdi 的 LLN 也有介绍。自主 Pdi 仅与强制吸气时的膈肌活动度速度和幅度有微弱的相关性。
膈肌超声是一种易于进行和可重复的诊断工具，可用于非侵入性评估膈肌活动度和厚度。它补充但不替代呼吸肌力量测试。
