Respiratory biofeedback accuracy in chronic renal failure patients: a method comparison

OBJECTIVE: To analyse respiratory biofeedback effects on respiratory muscle strengthening in chronic renal failure patients. DESIGN: Randomized controlled study. SETTING: Nephrology and dialysis centre. SUBJECTS AND INTERVENTION: Forty-one end-stage renal patients on haemodialysis treatment were allocated into three groups: control (n = 10), G-1 (inspiratory muscle training using Threshold IMT device; n = 16) and G-2 (biofeedback; n = 15) and given respiratory muscle training (three sessions/week for six weeks). MAIN MEASURES: Forced vital capacity (FVC), expiratory volume in the first second (FEV(1)), FEV(1)/FVC ratio, maximal voluntary ventilation (MVV) and maximal inspiratory (MIP) and expiratory (MEP) pressures were measured before and after the respiratory muscle training programme. RESULTS: Both training methods were efficient since we found an increase after training in the FVC in the G-1 group (from 2.45 ± 0.17 to 2.85 ± 0.16; P = 0.001) and in the G-2 group (from 2.35 ± 0.19 to 2.55 ± 0.19; P = 0.007), in the FEV(1) in G-1 (from 2.18 ± 0.16 to 2.46 ± 0.14; P = 0.01) and in G-2 (from 1.97 ± 0.17 to 2.20 ± 0.15; P < 0.0001), MIP in G-1 (from 70.63 ± 4.03 to 108.75 ± 7.41; P < 0.0001) and in G-2 (from 67.67 ± 5.02 to 96.33 ± 8.30; P < 0.001) and MEP in G-1 (from 73.13 ± 5.10 to 82.50 ± 6.74; P = 0.007) and in G-2 (from 67.67 ± 5.41 to 76.00 ± 4.29; P = 0.002). CONCLUSIONS: Respiratory biofeedback is efficient as a respiratory muscle training modality for patients with chronic renal failure.