Effects of Progressive Inspiratory Muscle Training on Lung Volume and Respiratory Strength in Patients With...

Chronic kidney disease can present changes in thoracic cavity volume and respiratory muscle weakness, even in the pre-dialysis stage. However, there is little evidence on the effects of inspiratory muscle training in these patients.

This was a randomized clinical trial which comprised patients with Chronic Kidney Disease in stages 3, 4, and 5 undergoing conservative treatment, allocated experimental group (EG) with progressive loading (up to 50% of maximal inspiratory pressure [MIP]) and control group (CG) with a fixed load (5 cmH₂O) and no load progression performed daily for 8 weeks. The outcomes assessed were thoracic cavity volumes, as measured by optoelectronic plethysmography, and inspiratory and expiratory respiratory muscle strength.

A total of 30 patients completed the study. All volumes significantly increased at the end of the protocol with a large effect size, but only the pulmonary thoracic cavity volume showed a significant interaction (F = 3.698; p = 0.042). There was an increase in inspiratory muscle strength in the EG (73.88-90.35 cmH₂O; p < 0.001) and in the CG (70.85-86.92 cmH₂O; p = 0.001), as well as in expiratory muscle strength in the EG (97.71-108.53 cmH₂O; p = 0.001) and in the CG (80.69-94.77 cmH₂O; p = 0.004).

Daily IMT increased thoracoabdominal volumes, particularly pulmonary rib cage volume in the progressive-load group, as well as respiratory muscle strength in patients with pre-dialysis CKD. However, progressive-load IMT was not superior to minimal-load training.