Can Brief Exposure to Hyperoxia Improve Function After Chronic Spinal Cord Injury?

This proof-of-principle study will include a small number of participants with subacute or chronic (>3 months post-injury), severe spinal cord injury (i.e., AIS A, B or C). After screening for potential contraindications, participants will attend 4 experimental sessions. In each session, their sensory or reflex function will be tested at regular intervals. Once baseline recordings are established, participants will be given either room air or 99% oxygen to breathe through a face mask for 2 minutes. It will be determined if breathing 99% oxygen results in a change in the sensory and motor functions recorded before and shortly after breathing oxygen.

Administration of a high concentration of oxygen at atmospheric pressure for a short duration has been completed without adverse effects in healthy individuals, and individuals with various forms of injury including chronic obstructive lung disease, traumatic brain injury, stroke, and spinal cord injury. Duration of administration has ranged from 3 min to 4 hours without adverse effects.

If this initial trial indicates that improvements in sensory and motor function are induced by this short exposure, exploration of therapeutic ways to increase blood flow to the spinal cord will be undertaken

Inclusion criteria

• Individuals with traumatic SCI with onset ≥3 months prior,
• Between 18 - 65 yr old,
• ASIA Impairment Scale at discharge classified as A, B or C,
• Injury level between C5 and T10,
• Able to give informed, written consent.

Exclusion criteria

• Frequent uncontrolled autonomic dysreflexia,
• Uncontrolled high blood pressure,
• Cardiac or cardiovascular disease,
• Cancer,
• Active urinary tract infection,
• Active pressure sores,
• Signs of deep vein thrombosis in the legs,
• Severe swelling of the feet and/or legs,
• Severe cognitive impairment,
• Pulmonary dysfunction such as chronic obstructive pulmonary disease or acute respiratory infection,
• Any condition which would be exacerbated by sitting or lying in one position for 2 hours, such as low back pain
• Pregnancy.