Effects of intradialytic inspiratory muscle training at different intensities on diaphragm thickness and functional capacity: clinical trial protocol in patients undergoing haemodialysis

INTRODUCTION: Patients with end-stage renal disease (ESRD) undergoing haemodialysis (HD) commonly present with a sedentary behaviour and reduced functional capacity, factors that can compromise their prognosis. Intradialytic inspiratory muscle training (IMT) can increase respiratory muscle strength and, consequently, improve functional capacity, besides being easy to apply, cheap and performed in a supervised setting. However, few studies show the effects of this type of training applied at different intensities in this population. This study aims to compare the effects of IMT at different intensities in adults with ESRD undergoing HD. METHODS AND ANALYSIS: A randomised, double-blind, sham-controlled trial will be conducted on 36 subjects randomly allocated into three groups: IMT at intensities of 30% or 50% of maximal inspiratory pressure (intervention groups), or 10% of maximal inspiratory pressure (sham-IMT). All the interventions will be supervised and performed three times per week, for 12 weeks, totalling 36 sessions. The primary outcomes are the 6-minute walk test, diaphragm thickness and the response of VO(2)peak post-intervention. Respiratory muscle strength, 24-hour ambulatory blood pressure measurement and the Kidney Disease Quality of Life 36-item short form survey will be evaluated as secondary outcomes. ETHICS AND DISSEMINATION: This study has been approved by the Research Ethics Committee of the Hospital de Clínicas de Porto Alegre (ID: 2020-0458). The results of this study will be disseminated by conference presentations and peer-reviewed journal. TRIAL REGISTRATION NUMBER: NCT04660383.