Targeted resistive ventilatory muscle training in chronic obstructive pulmonary disease

Abstract

To overcome the problem of altered breathing strategy during resistive ventilatory muscle training (VMT), we used a single-orifice inspiratory resistance together with a target feedback device (TFD) in patients with chronic obstructive pulmonary disease (COPD). In a preliminary study (study A), we showed that the resistance plus TFD was effective in controlling breathing strategy. We subsequently used the resistor plus TFD in a 5-wk study (study B) of VMT in 17 COPD patients who were randomized into high-intensity (HI) and low-intensity (LI) training groups. Compared with the LI group, the HI group showed significant increases in static maximal inspiratory pressure (21.3 vs. 5.0 cmH2O), maximal sustained ventilatory capacity (MSVC, 3.2 vs -0.1 l/min, sustained maximal mouth pressure (12.1 vs. 0.6 cmH2O), mean mouth pressure (6.9 vs. 3.9 cmH2O), peak inspiratory flow rate (12.3 vs. 4.0 l/min), and maximal sustained work rate (12.2 vs. 4.2 cmH2O.l-1.min-1). We conclude that targeted VMT with control of breathing strategy improves both ventilatory muscle strength and endurance.

Inspiratory muscle training in chronic airflow limitation: comparison of two different training loads with a threshold device

“…In Group 2 only 3 patients increased their IMPO and it was due to an increment in both factors. These results are in agreement with those reported by BELMAN and SHADMEHR [10], who also showed that IMT increases Vmax.…”

“…In agreement with previous reports [9][10][11][12][13][14], our study confirms that the magnitude of the load used for inspiratory muscle training is a critical determinant of the results in patients with CAL; with an adequate load, IMT has a favourable effect on inspiratory muscle function, dyspnoea and physical capacity. Our study also shows that maximal inspiratory muscle power output is useful for evaluating the effects of training, and that patients can develop a strategy to cope with respiratory loads without reaching the critical area of inspiratory muscle fatigue [18].…”

“…In the present study, we used 30% PImax as a target load, based on the report of LARSON et al [9], who studies using a sufficient target load [9][10][11]13]. Results for endurance cannot be compared, since we used SIP, whilst most of the other studies have evaluated Tlim (endurance time).…”

“…This problem can be solved if the patient uses a system to control the pressure or flow developed during training or uses a threshold pressure device, which is independent of the flow rate [9][10][11][12][13][14]. Whilst studies in which the load is not controlled are controversial, the results of those in which a target load is achieved and maintained have demonstrated that IMT improves inspiratory muscle strength and/or endurance in patients with CAL [9][10][11][12][13][14].…”

“…BELMAN and SHADMEHR used over 50% PImax [10]; HARVER et al employed around 30% [11]; DEKHUIJZEN et al [14] trained with a load of 70%; and PATESSIO et al [13] used 50% PImax. With threshold inspiratory trainers, on the other hand, the loads used have been between 30-43% PImax [9,12].…”