Short-term effect of inspiratory muscle training on pulmonary function after mitral valve replacement: Quasi-experimental study

BACKGROUND: After cardiac surgery, various pulmonary complications develop which require specific care. These complications affect pulmonary functions and can lengthen the hospital stay of patients, causing increased hospital costs and becoming an important cause of morbidity and mortality. OBJECTIVES: To investigate the short-term effect of inspiratory muscle training on pulmonary function after mitral valve replacement. METHODS: A sample of Thirty five patients (35.5±3.29 years) who underwent mitral valve replacement. Spirometric parameters were measured before and after intervention including forced vital capacity (FVC), forced expiratory volume in the first second (FEV1) and ratio of forced expiratory volume in the first second to forced vital capacity (FEV1/FVC). All participants had received postoperative Inspiratory muscle training (IMT) from the first day in the inpatient unit after discharge from intensive care unit till hospital discharge. Paired t-test was used to investigate differences between means of pulmonary function measures (P < 0.05). Effect size was calculated and post hoc power analysis was performed. RESULTS: After one week of postoperative IMT there was a statistically significant improvement in the studied spirometric parameters (FVC, FEV1, FEV1/FVC) (p = 0.01). All studied spirometric parameters showed very large effect size (d >0.8). The post hoc power analysis revealed that the study power was more than 90%. CONCLUSION: One week of post-operative IMT may have a beneficial short-term effect in improving pulmonary functions after mitral valve replacement.