Ventilatory aspects of sleep and activity in patients with neuromuscular disorders

Patients with cervical cord injuries (M) and slowly progressive neuromuscular diseases, such as prior polio and muscular dystrophy, often have decreased ventilatory capacity. This could affect both their daytime level of activity and sleep quality.

In CCI-patients, one question was whether they would benefit from trunk support in physical activity such as arm ergometry. Some patients exhibited desaturation in oximetry during arm ergometry, and a second question was whether they would also be at risk for nocturnal desaturations. Thirdly, we aimed at establishing the prevalence of nocturnal upper airway obstruction.

In patients with neuromuscular diseases the aims were to evaluate the treatment effect of nasal intermittent positive pressure ventilation (NIPPV) and to evaluate whether training in combination with assisted ventilation could improve respiratory muscle function and activities of daily living (ADL). During arm ergometry with use of trunk support oxygen uptake at steady state decreased and maximal performance time increased. Ear oximetry values tended to decrease during work and increased to resting values after work had stopped. When studying the same patients during both sleep and exercise, only one of nine showed desaturations in both conditions. In another patient group over night recordings showed an obstructive respiration in five of 33 (15%) CCI patients. There was an inverse correlation between oxygen desaturation index and motor score in a subgroup with complete CCI injury.

In patients with neuromuscular diseases whole night polysomnographic recordings showed that NIPPV ameliorated sleep fragmentation and blood gases and allowed rest of accessory muscles in a majority of the patients and relieved symptoms in all. In patients with prior polio, inspiratory muscle training in addition to assisted ventilation, improved inspiratory endurance and most patients improved in wellbeing and ADL.

In conclusion, trunk support should be considered when CCI patients are performing exercise affecting their postural balance. Lean and active CCI patients able to perform arm ergometry do not risk nocturnal hypoxemia. Obstructive sleep apnea was over-represented in patients with CCI in comparison to general Swedish population, not clearly related to daytime symptoms. NIPPV may relieve daytime symptoms by allowing nocturnal rest of accessory respiratory muscles and diminished sleep fragmentation. Inspiratory muscle training further increased the effect of assisted ventilation with respect to inspiratory muscle endurance and ADL in a selected group of prior polio patients.