Measuring thoracic excursion: reliability of the cloth tape measure technique.

OBJECTIVE To assess the reliability of using a cloth tape measure to determine thoracic respiratory excursion as a measurement of chest expansion or mobility. METHODS Physicians and residents experienced in osteopathic manipulative treatment measured thoracic excursion with a cloth tape measure held around the circumference of healthy male subjects' chests at two levels. Upper thoracic excursion measurements were taken at the level of the fifth thoracic spinous process and the third intercostal space at the midclavicular line. Lower thoracic excursion measurements were taken at the level of the 10th thoracic spinous process and the xiphoid process. At peak inhalation and exhalation, three examiners measured thoracic excursion at both levels. In the first session (n=5), examiners measured the same subject inhalation and exhalation. In the second session (n=4), examiners measured separate respiratory cycles. For each session, interexaminer intraclass correlation coefficients (ICCs) were calculated for thoracic excursion, inhalation, and exhalation in the upper and lower positions using a two-way random-effects analysis of variance model. RESULTS Intraclass correlation coefficients for thoracic excursion ranged from 0.81 to 0.91 (95% confidence interval, 0.69-0.99) at both measurement levels in both sessions. When inhalation and exhalation were considered separately, interexaminer ICCs were 0.99 and greater. Standard deviations for measurements of each subject's thoracic excursion at both levels ranged from 0.5 cm to 0.8 cm with a mean of 0.6 cm. CONCLUSION The method of using a tape measure to assess thoracic excursion was highly reliable in men, resulting in ICCs of substantial reliability. The SDs at each level of measurement indicate that this method may be most useful in measuring changes in thoracic excursion that are expected to be 0.6 cm or greater.