Inspiratory muscle training to enhance recovery from invasive mechanical ventilation

Abstract

Inspiratory muscle weakness is a consequence of prolonged mechanical ventilation and may contribute to the residual physical disability which has been observed in intensive care survivors. Inspiratory muscle weakness is associated with duration of mechanical ventilation, with those ventilated for 7 days or longer most at risk of developing both strength and endurance deficits.Specific resistance training of the inspiratory muscles (inspiratory muscle training) improves inspiratory muscle strength and endurance in normal people, athletes and patients with a wide variety of underlying pathologies. Mechanisms of improvement include proliferation of both Type 1 and Type 2 inspiratory muscle fibres, enhanced metabolism resulting in reduced lactate production, attenuation of a fatigue-induced metaboreflex, adaptations to neural pathways and modulation of the perception of dyspnoea.Furthermore, inspiratory muscle training enhances exercise tolerance and reduces dyspnoea in both patients and athletes, while improving quality of life for patients with chronic lung or heart disease.There is a lack of evidence for inspiratory muscle training in intensive care patients, despite the potential benefits of training in this group. This project explores the feasibility, safety and efficacy of inspiratory muscle training in intensive care patients who have been mechanically ventilated for 7 days or longer, as this subset of patients is most likely to demonstrate inspiratory muscle weakness and therefore benefit from specific training. This project includes patient-centred outcome measures, as most studies of inspiratory muscle training to date have focused solely on impairments, rather than the patient experiences of quality of life, physical function or dyspnoea.Study 1 establishes the safety and feasibility of high-intensity interval-based inspiratory muscle training in selected ventilator-dependent patients. Across 195 inspiratory muscle training sessions, there were no adverse events recorded during or immediately following the treatment. No significant changes were observed in heart rate, blood pressure, respiratory rate or oxygen saturation. Furthermore, mean training pressures increased by a mean difference of 18.6 cm H2O across the 10 patients studied. Thus Study 1 confirms that inspiratory muscle training is safe in selected ventilator-dependent patients.-ii- (mean difference 11%), but not endurance, while quality of life improved more in the experimental group than the control (mean difference 12%). Improvements in physical function and dyspnoea were equivalent. Thus 2 weeks of inspiratory muscle training improves inspiratory muscle strength and quality of life in the post-weaning period.-iiiFinally, Study 5 is a protocol for a randomised trial of inspiratory muscle training performed by patients while mechanically-ventilated. Study 5 measures the impact of inspiratory muscle training on duration of mechanical ventilation, as well as residual inspiratory muscle strength and endurance, quality of life, physical f...

The effects of inspiratory muscle training on cardiorespiratory functions in juvenile idiopathic arthritis: A randomized controlled trial

“…These adaptations may include increased perfusion/muscle metabolism in inspiratory muscles, transformation of muscle fiber type and/or neural plasticity at respiratory synapses in the central nervous system. 38 Although there was an increase of approximately 12% in the PE max before and after the treatment in the exercise group, no between-group difference was detected for PE max at the time of post-treatment assessment.…”

“…Although there is no confirmed mechanism, it is highly possible that this significant increase in PI max is a result of adaptations in the musculoskeletal and peripheral nervous systems following long‐term IMT. These adaptations may include increased perfusion/muscle metabolism in inspiratory muscles, transformation of muscle fiber type and/or neural plasticity at respiratory synapses in the central nervous system 38 . Although there was an increase of approximately 12% in the PE max before and after the treatment in the exercise group, no between‐group difference was detected for PE max at the time of post‐treatment assessment.…”

“…IMT was found effective on improving functional status, enhancing aerobic exercise capacity, decreasing disease activity, increasing respiratory muscle strength and vital capacity in adult patients with rheumatic disease 17,18 . Furthermore, IMT was demonstrated beneficial for increasing oxygen perfusion and muscle metabolism in both respiratory and extremity muscles, and inducing neural plasticity at respiratory synapses in different populations 19 . However, no previous studies utilized IMT in children with JIA.…”

“…17,18 Furthermore, IMT was demonstrated beneficial for increasing oxygen perfusion and muscle metabolism in both respiratory and extremity muscles, and inducing neural plasticity at respiratory synapses in different populations. 19 However, no previous studies utilized IMT in children with JIA. Therefore, the present study aimed to investigate the effects of IMT primarily on respiratory muscle strength, and secondarily on pulmonary functions, aerobic exercise capacity, functional capacity, and QoL in children with JIA.…”