Wait J L, Nahormek P A, Yost W T, Rochester D P
Pulmonary Division, University of Texas Southwestern Medical Center, Dallas 75235.
J Appl Physiol (1985). 1989 Oct;67(4):1560-8. doi: 10.1152/jappl.1989.67.4.1560.
To characterize the relationship of changes in diaphragmatic thickness during contraction to changes in lung volume, we developed a technique to measure diaphragm thickness based on M-mode ultrasonography. First, diaphragmatic thickness was measured in situ at necropsy with ultrasound and verified by measuring the same resected segment of diaphragm by ruler (correlation coefficient = 0.93, slope = 0.97). The technique of imaging the diaphragm in living subjects was developed by using a 15-MHz transducer coupled to an M-mode echocardiograph. Ten normal male volunteers were studied while sitting. The ultrasound transducer was held between the ribs in the ninth lateral interspace, and tidal volume was measured by spirometry. The thickening fraction (TF) was calculated as TF = (thickness at peak inspiration - thickness at end expiration)/thickness at end expiration for each of a series of different sized breaths. The function, TF vs. lung volume, for a range of volumes was linear for each subject and had intrasubject reproducibility with intersubject variability. We conclude that diaphragmatic TF is related to function as determined by lung volume, and this may prove to be a useful technique for in vivo studies of diaphragmatic function.
为了描述膈肌收缩时厚度变化与肺容积变化之间的关系，我们开发了一种基于M型超声测量膈肌厚度的技术。首先，在尸检时用超声原位测量膈肌厚度，并通过用尺子测量同一切除的膈肌段进行验证（相关系数 = 0.93，斜率 = 0.97）。利用与M型超声心动图相连的15兆赫换能器开发了在活体中对膈肌成像的技术。对10名正常男性志愿者坐着时进行了研究。超声换能器置于第九肋间外侧的肋骨之间，用肺量计测量潮气量。对于一系列不同大小的呼吸，增厚分数（TF）计算为TF =（吸气峰值时的厚度 - 呼气末时的厚度）/呼气末时的厚度。对于每个受试者，在一定容积范围内，TF与肺容积的函数关系呈线性，且在受试者内具有可重复性，受试者间存在变异性。我们得出结论，膈肌TF与由肺容积决定的功能相关，这可能被证明是一种用于膈肌功能体内研究的有用技术。
