Continuous positive airway pressure treatment does not normalize the prolonged reflex inhibition to inspiratory loading in obstructive sleep apnea.

In obstructive sleep apnea (OSA), the short-latency inhibitory reflex (IR) of inspiratory muscles to airway occlusion is prolonged in proportion to the severity of the OSA. The mechanism underlying the prolongation may relate to chronic inspiratory muscle loading due to upper airway obstruction or sensory changes due to chronic OSA-mediated inflammation. Continuous positive airway pressure (CPAP) therapy prevents upper airway obstruction and reverses inflammation.

Effect of airway inflammation on short-latency reflex inhibition to inspiratory loading in human scalene muscles.

The short-latency reflex inhibition of human inspiratory muscles produced by loading is prolonged in asthma and obstructive sleep apnoea, both diseases involving airway and systemic inflammation. Both diseases also involve repetitive inspiratory loading. Although airway mucosal afferents are not critical components of the normal reflex arc, during airway inflammation, prolongation of the reflex may be caused by altered mucosal afferent sensitivity, or altered central processing of their inputs.

Respiratory care of patients with cervical spinal cord injury: a review.

Respiratory complications following cervical spinal cord injury are common and are the leading cause of morbidity and mortality after this type of injury. Impaired mechanics of ventilation, poor cough, increased secretions and bronchospasm predispose to atelectasis, pneumonia and exacerbations of respiratory failure. Prolonged mechanical ventilation and tracheostomy are often required.

Differential effects of low-intensity motor cortical stimulation on the inspiratory activity in scalene muscles during voluntary and involuntary breathing.

To assess the cortical contribution to breathing, low-intensity transcranial magnetic stimulation (TMS) was delivered over the motor cortex in 10 subjects during: (i) voluntary static inspiratory efforts, (ii) hypocapnic voluntary ventilation (end-tidal CO(2), 2.7±0.4% mean±SD), and (iii) hypercapnic involuntary ventilation (end-tidal CO(2), 6.

Reproducibility of the short-latency reflex inhibition to loading of human inspiratory muscles.

Loading of inspiratory muscles produces a profound short-latency inhibitory response (IR) of the electromyogram (EMG), followed by an excitatory response (ER). Duration of IR correlates positively with the apnoea hypopnoea index in obstructive sleep apnoea (OSA) patients, for whom measurement of this reflex may allow the assessment of a physiological response to therapy. To test the reliability of reflex measurement, we studied 11 human subjects on 4 separate days.