Inspiratory muscle training for diaphragm dysfunction after cardiac surgery.

Abstract

Diaphragm dysfunction is a complication of cardiac surgery with partial or absent spontaneous recovery in most cases. Surgical diaphragm plication represents the only option when symptoms persist. Because training improves functional nerve recovery after a nerve lesion, we hypothesized that early diaphragm muscle training may be beneficial. A prospective, randomized at 2:1 ratio, controlled trial of diaphragm training using an adjustable pressure device (Threshold; Philips Respironics Inc, Murrysville, Pa) versus no training (sham device) was performed in patients with diaphragm paralysis after major cardiac surgery. This 1-year study recruited consecutive adult patients with sniff fluoroscopy-defined diaphragm paralysis after coronary bypass, valve replacement, or both. The outcome measures were diaphragm function recovery assessed by sniff fluoroscopy, maximum inspiratory and expiratory pressures, and lung function tests. A total of 69 patients were randomized. At 12 months, 52 patients completed the study assessments, 36 in the treatment group and 16 in the control group. Inspiratory muscle training produced a significant improvement of diaphragm mobility after 12 months (P < .001). Most patients in the training group (77.78%) experienced a partial improvement (41.67%) or achieved a complete improvement (36.11%) versus no improvement (87.5%) or partial recovery (12.5%) among controls. Inspiratory muscle training may improve inspiratory muscle strength and increases paralyzed diaphragm mobility.