Novel versus Traditional Inspiratory Muscle Training Regimens as Home-Based, Stand-Alone Therapies in COPD: Protocol for a Randomized Controlled Trial

Figures & data

Figure 1 Comparison of the maximal inspiratory effort slopes obtained via the TIRE method and traditional inspiratory muscle assessment utilizing a threshold device.

Notes: The TIRE method elicits significantly higher inspiratory pressures that last throughout the entire inspiration, from residual volume (RV) to total lung capacity (TLC), while traditional IMT provides a square-shaped curve with limited pressures and inspiratory duration. SMIP derives as the area under the pressure-time curve in the TIRE assessment.

Figure 2 Outline of study design. Subjects are assigned to one of three home-based inspiratory muscle training groups and expected to train for 8 weeks.

Table 1 Proposed Training Characteristics per Study Group

Group	Device	Training Load	Training Volume	Training Frequency
TIRE IMT	PrO2	On-screen training template set at 50% of the subject’s MIP and SMIP.	Six levels (A-F) with 6 inspirations per level for up to 36 efforts per session. Pre-set recovery times between breaths: 60 seconds at level A to 50, 40, 30, 20 and 10 seconds at levels B to F, respectively.	1/day, 8 weeks
Threshold IMT	Threshold	One-way spring-loaded valve set at 50% of the subject’s MIP.	36 inspirations performed using the device within a 30-minute period.	1/day, 8 weeks
Sham IMT	Threshold	One-way spring-loaded valve set to its minimal resistance (- 9 cmH2O).	36 inspirations performed using the device within a 30-minute period.	1/day, 8 weeks

Abbreviations: MIP, maximal inspiratory pressure; SMIP, sustained maximal inspiratory pressure; TIRE, test of incremental respiratory endurance.

Figure 3 Graphic presentation of a sustained maximal inspiratory effort performed using the PrO2 device and software. In this example, the user achieved a MIP of 90 cmH2O, a SMIP of 606 PTU reflecting the area under the pressure-time curve. The entire maneuver lasted 15 seconds.