Inspiratory muscle training improves muscle oxygenation and efficiency of extradiaphragmatic inspiratory muscles in difficult to wean (DTW) patients

Abstract

<b>Introduction:</b> Inspiratory muscle training (IMT) improves respiratory muscle function in DTW patients. It is unknown whether IMT affects extradiaphragmatic inspiratory muscle oxygenation and efficiency. <b>Aim:</b> to evaluate the effect of high-intensity IMT versus sham IMT on inspiratory muscle oxygenation and efficiency during a loaded breathing task at 30% of baseline Pimax in DTW patients. <b>Methods:</b> 48 patients (age:57±16y) performed daily IMT sessions (4 sets, 6–10 breaths) until weaning success or for 28 consecutive days. The IMT group trained at the highest possible load (30-50% Pimax) and sham group at 10%Pimax. Work of breathing (WoB) and power of breathing (PoB) were measured and scalene (SCA) and sternocleidomastoid (SCM) oxygen saturation responses were assessed by near-infrared spectroscopy. Muscle efficiency was expressed as change in muscle oxygenation&nbsp;per unit increase in PoB. <b>Results:</b> After the intervention period, both groups significantly improved WoB, and SCA muscle efficiency. Only the IMT group improved PoB, SCA and SCM muscle oxygenation. In addition, only the improvement in SCM muscle efficiency was significantly higher in the IMT group compared to the sham group (Table 1). <b>Conclusions:</b> High intensity IMT as compared to sham training induced greater improvements in SCM efficiency in DTW patients.