Prediction of Normal Spirometric Values for Adults Incapable of Standing

Predicting the normal values of pulmonary function for an individual to be compared with the individuals performance on a test is an important part of the process of pulmonary evaluation. The consensus among pulmonologists is that the most reliable predictors of pulmonary function are the individuals sex, age, and standing height. Prediction equations using these factors have been developed independently by different investigators; however, our patient population includes amputees, spinal cord injuries, and others who are unable or incapable of standing upright, for whom the generally available prediction equations do not apply.

While considering other physical characteristics that might be predictors of pulmonary function and also might be readily determined, we speculated that a persons sitting height should be proportional to his or her standing height and would therefore be a reasonable substitute when standing height could not be measured. We found the opportunity to test this hypothesis during a repeat study of pulmonary function in normal individuals after a 15-year interval.
Materials and Methods
A total of 208 of the original sample of 988 individuals studied in 1969 were still residing in the Willamette River Valley of western Oregon. Nine subjects were rejected on the basis of abnormal responses to questions on a pretest questionnaire. The remaining sample population consisted of 199 men and women. All subjects were healthy white lifelong nonsmokers with no history of cardiopulmonary disease or exposure to ambient or occupational air pollutants. Standing height (H) was measured in inches with the subject standing with the back of the head against a wall and without shoes, comparable to the method of Ferris and Stroudt. Sitting height (S), also in inches, was measured with a specially constructed gauge functionally similar to a caliper. It consisted of a base that serves as a seat for the subject, a back which is fastened perpendicularly to the base and supports the height scale, and a triangleshaped height transfer block which is held against the top of the subjects head and the height scale to measure the sitting height. Studies of pulmonary function were performed in the standing position. Standing-to-sitting height ratios (H/S) were calculated and analyzed for frequency distribution. Means and standard deviations were calculated for age (A) and for sitting and standing heights using standard methods. The relationships between standing and sitting heights, age, sex, and spirometric values were determined using regression analysis. The study was approved by the Oregon State University Human Studies Committee.

Category: Health

Tags: adults incapable of standing, physical characteristics, Pulmonary Function