The Effects of IMT on Exercise Capacity, Dyspnea and Lung Functions in LTx

Overview

Inspiratory Muscle Training (IMT), which is used to strengthen the respiratory muscles, is one of the techniques used in PR. It is mostly used in patients with chronic obstructive pulmonary disease, and has been shown to be beneficial for functionality and also for relieving dyspnea perception. It is reported in the guidelines that IMT has additional benefit for endurance in COPD patients. However, there are no studies related to its use and effectiveness in lung transplantation. In this study, we hoped to increase these known benefits by adding IMT to the standard Pulmonary Rehabilitation. There are two main objectives of this study: 1. to examine the effect of respiratory muscle training on exercise capacity in lung transplantation candidates, 2. to compare dyspnea perception and lung function changes between the IMT+PR group and the PR group.

The patients in the lung transplantation waiting list were included the study. These patients were with severe lung disease requiring transplantation, and that the intervention was undertaken before any lung transplantation. The patients were eligible for inclusion if they have: a diagnosis of terminally severe lung disease, being listed for lung transplantation, medically stable, had no orthopedic or cardiac problems that would prevent them from exercising and had no transfer problem to the PR centre. Participants who meet the study inclusion criteria and complete the baseline assessments were randomly allocated into one of the two groups: namely Pulmonary Rehabilitation plus Inspiratory Muscle Training Group (IMT+PR) or Pulmonary Rehabilitation Group (PR) using a numbered series of 34 prefilled envelops specifying group assignment generated by a computer-based program. All patients underwent supervised PR program on 2 days per week for 3 months. Apart from that, they were asked to perform the home exercise program which was scheduled as 3 days per week and fill out the exercise follow-up form. The study group was provided with IMT in addition to the standard program. Statistical analysis was conducted using SPSS (version 15, USA). The Shapiro-Wilk statistic was used to test the normality of the distribution of all variables. Nonparametric tests were used in comparison, because the number of samples and the standard deviations of in-group chance (∆) were very large. The Wilcoxon Signed Rank Test was used to compare the pre- and post-treatment data of the groups, and the Mann-Whitney U test was used in the group-wise comparison. Nonparametric variables were expressed as median (minimum-maximum), and descriptive variables as percent. The chi-square test was used for categorical variables. Significance level was accepted as p \<0.05 in all tests. We estimated that a sample size of 19 patients for each group to have 80% power with 5% type 1 error level to detect a minimum clinically significant differences of 54 meters of the 6-min walk test with the highest standard deviation of the study parameters.