Introduction: Studies suggest that adherence to pulmonary rehabilitation (PR) is low among veterans with COPD. This can be explained in part because PR programs are typically hospital-based, which limits accessibility. Home-based therapies are then a promising approach that might produce equivalent benefits to PR.
Case Report: A 74-year-old male veteran with moderate COPD (height= 175.26cm, weight= 97.52kg, former smoker with 53 pack-years) unable to attend PR underwent an alternative 8-week home-based inspiratory muscle training (IMT) protocol using the Test of Incremental Respiratory Endurance (TIRE), a novel method which has not been previously studied in COPD. Unlike most traditional protocols based solely on the maximal inspiratory pressure (MIP), TIRE training is targeted to enhance the sustained maximal inspiratory pressure (SMIP) and inspiratory duration (ID) which are obtained during a forceful inspiration from residual volume to total lung capacity. The veteran received a tablet with the TIRE software installed through which he trained using an electronic manometer (PrO2®, Design Net, Smithfield, USA) connected via wireless technology. Training consisted of six levels (A-F) with six inspirations at each level for a total of 36 breaths daily.
Recovery times between breaths decreased from 60 to 10 seconds as the subject advanced each level. Training data were stored in the tablet and retrieved for interrogation. After 8 weeks of training with a 62.5% compliance rate, the veteran improved all inspiratory muscle measures (pre- vs. post-intervention MIP= 59 vs. 86cmH2O, Δ= 45.7%; SMIP= 380 vs. 612PTU, Δ= 61.1%; ID= 12.5 vs. 18seconds, Δ= 44%), FEV1 and FVC (61 vs. 68%predicted, Δ= 11.5%; 70 vs. 75%predicted, Δ= 7.1%), CAT score (9 vs. 8), mMRC dyspnea scale (1 vs. 0), 6-minute walk distance (462.1 vs. 509.0meters, Δ= 10.1%), St. George’s Respiratory Questionnaire Total, Activity and Symptom scores (26.6 vs. 20.5, Δ= -22.6%; 36.3 vs. 12.1, Δ= -66.6%; 38.2 vs. 27.8, Δ= -27.1%, respectively) and the depression component of the Hospital Anxiety and Depression scale (4 vs. 2).
Discussion: The subject’s observed gains in inspiratory muscle strength and endurance seem to have translated into better lung function, lower impact of COPD on health status, reduced dyspnea, improved functional exercise capacity, better quality of life and lower depressive symptoms. This case highlights the value of an alternative rehabilitative modality in COPD implemented when our team was confronted with the dilemma of either providing a rather motivated patient with some or no training option, since he was unable to attend PR.