2000 OPEN FORUM Abstracts
THE EFFECTS OF INSPIRATORY MUSCLE TRAINING IN OUTPATIENT PULMONARY REHABILITATION
Hoberty PD, EdD RRT, Hastwell W, Clanton TL, PhD, Rittinger M, BS RRT and Diaz PT, MD. The Ohio State University, Columbus, Ohio
Background: Inspiratory muscle training (IMT) is a common component in outpatient pulmonary rehabilitation; however, the physiological benefits of IMT and its contribution to the outcomes of rehabilitation services have not been determined. The purpose of this study was to determine the effects of IMT on breathing and general physical function. Method: The sample consisted of 25 patients with chronic obstructive pulmonary disease that were referred to an 8-week multidisciplinary outpatient pulmonary rehabilitation program at a comprehensive wellness center. These patients were randomly assigned either to a control group (10 patients, 7 males and 3 females) to receive IMT at 10% maximal inspiratory pressure (MIP) or to a test group (15 patients, 9 males and 6 females) to receive IMT starting at 40% MIP and increasing as tolerated. Both groups used a commercially-available, single-patient use, spring-loaded threshold IMT trainer. Instruction and practice were provided at the beginning of rehabilitation. Training was conducted on-site three days per week and independently at home on other days. Patients kept a written log of home sessions. Subjects were tested at the beginning and at the end of the program using a discontinuous incremental threshold loading test (DITLT) which required breathing at 2-minute intervals at 6 levels of inspiratory resistance beginning at 30% of measured MIP and concluding at 80% or until symptom limited. Patients rated their perceived dyspnea and breathing effort on a 10-point modified BORG scale at each level completed. The six-minute walk distance was also determined pre- and post-program. Independent t-tests demonstrated that the groups were similar as to age, diagnosis, and severity of obstruction. The groups were not different on pre-program testing on the DITLT, MIP or the six-minute walk distance. Data were tabulated and an ANOVA with repeated measures was performed to make pre- to post-comparisons.
Results: For all 25 subjects combined, there were significant pre- to post-program improvements in MIP, maximal level completed during the DITLT, perceived dyspnea and exertion at the maximal level, and in six-minute walk distance (p < .05). However, there was no significant difference between the control and test groups on any of these measures. Conclusion: The results indicate that comprehensive pulmonary rehabilitation leads to improvements in breathing and physical function. However, IMT at the conventional training level (>30% MIP) does not appear to produce better outcomes than training at only 10% MIP.
Supported by Respironics, Inc.