Evaluation of a device to improve respiratory muscle strength in people with lung diseases

INTERVENTION: This is a randomized, controlled, multicenter, superiority clinical trial with two parallel groups, a 1:1 allocation ratio, and blinded outcome assessors, designed to compare the effects of isolated inspiratory muscle training with the effects of combined respiratory muscle training in patients with respiratory muscle dysfunction associated with pulmonary diseases. A total of 76 participants will be included, with 38 participants allocated to the control group and 38 participants allocated to the intervention group. Randomization will be performed by an independent researcher using a computer‐generated random sequence with variable block sizes of four and si Xparticipants and stratification according to recruitment setting. Allocation concealment will be ensured using opaque, sealed, sequentially numbered, and tamper‐proof envelopes prepared in advance and opened only after confirmation of eligibility criteria, signing of the Informed Consent Form, and completion of baseline assessments. Due to the characteristics of the intervention, blinding of participants and physical therapists responsible for delivering the training will not be possible. Outcome assessors will remain blinded to group allocation throughout the study and, whenever possible, statistical analysis will be performed using coded groups to preserve blinding of the researcher responsible for data analysis. The intervention protocol will last si Xweeks, with one training session per day, seven days per week. Each session will consist of 30 respiratory cycles organized into five sets of si Xbreaths, with an approximately one‐minute rest interval between sets and an average total duration of 15 to 20 minutes. Before beginning the training protocol, each participant will perform five respiratory cycles to become familiar with the device, using no load or a minimal load. The 38 participants in the control group will perform inspiratory muscle training using a conventional pressure‐threshold device, with an initial load corresponding to 50% of the maximal inspiratory pressure measured at baseline. The 38 participants in the intervention group will perform combined respiratory muscle training using the Bidirectional Integrated Respiratory Training System, operated through a multidirectional pneumomechanical device, with initial loads corresponding to 50% of the maximal inspiratory pressure and 50% of the maximal expiratory pressure measured at baseline. In the third week, maximal inspiratory pressure and maximal expiratory pressure will be reassessed, and training loads will be readjusted to 50% of the new maximal inspiratory pressure in the control group and to 50% of the new maximal inspiratory pressure combined with 50% of the new maximal expiratory pressure in the intervention group. In the sixth week, the final outcome assessment will be performed without further load adjustment. Participants recruited in the hospital setting will initially perform training under direct supervision of the research team and, if discharged before completing the six‐week intervention, will continue the CONDITION: Muscle Weakness ; Respiratory Tract Diseases PRIMARY OUTCOME: Maximal inspiratory pressure (MIP), expressed in cmH2O, as a measure of inspiratory muscle strength. It will be assessed at baseline (S0), at week 3 (S3), and at the end of week 6 (S6). The primary outcome will be the change in MIP over time and its comparison between groups. SECONDARY OUTCOME: Adherence to the training protocol, expressed as the percentage of completed sessions relative to the number of planned sessions during the six‐week intervention. Adherence will be compared between groups at the end of the intervention period (week 6). Inspiratory muscle endurance, assessed using a sustained‐load test corresponding to 30% of maximal inspiratory pressure (MIP). It will be assessed at baseline (S0), at week 3 (S3), and at the end of week 6 (S6), comparing changes in performance between groups. Maximal expiratory pressure (MEP), expressed in cmH2O, as a measure of expiratory muscle strength. It will be assessed at baseline (S0), at week 3 (S3), and at the end of week 6 (S6). The outcome will be the change in MEP over time and its comparison between groups. Perceived exertion assessed using the Borg Scale during the respiratory muscle training protocol. It will be recorded throughout the intervention to assess training tolerance and for comparison between groups. Ventilatory parameters obtained by ventilometry, including tidal volume (VT, mL), respiratory rate (RR, breaths/min), and minute ventilation (VE, L/min). They will be assessed at baseline (S0), at week 3 (S3), and at the end of week 6 (S6), with changes compared between groups. INCLUSION CRITERIA: Age 18 years or older and 65 years or younger; clinical diagnosis of pulmonary disease confirmed by medical evaluation and documented in the medical record; presence of respiratory muscle dysfunction associated with pulmonary disease, characterized by maximal inspiratory pressure (MIP) below 80% of the predicted value for se Xand age, according to reference equations validated for the Brazilian population; clinical stability at enrollment, without acute exacerbation of pulmonary disease or any other condition contraindicating the assessments or respiratory muscle training; adequate clinical and cognitive ability to understand the instructions and properly perform the assessment maneuvers and training protocol; and voluntary agreement to participate in the study by signing the Informed Consent Form.