MAXIMAL INSPIRATORY PRESSURE - LEARNING EFFECT AND TEST-RETEST RELIABILITY IN PATIENTS WITH CHRONIC OBSTRUCTIVE PULMONARY-DISEASE

Reliability of the maximal inspiratory pressure (PImax) was examined b y measuring PImax once a week for 4 weeks in 91 patients with chronic obstructive pulmonary disease using an aneroid pressure gauge. Five Pi max trials were conducted at each test. From the first to the fourth t est, the PImax increased by a mean of 9 cm H2O (SD = 10). From the thi rd to the fourth test, PImax increased by a mean of 2 cm H2O and perfo rmance appeared to be plateauing. The test-retest reliability coeffici ent was r = 0.97 for PImax measured at the third and fourth test sessi on. The 95 percent confidence interval for the absolute difference in PImax at the third and fourth test was 3 to 5 cm H2O. We conclude that performance of PImax improves with practice in naive COPD patients an d PImax is reliable when measured with an aneroid gauge by experienced data collectors if patients are given sufficient practice.