High Flow Oxygen Therapy After Spinal Cord Injury

In the UK, the annual incidence of acute spinal cord injury (SCI) is 19 new cases per million population, contributing to an estimated 50,000 people who are currently living with SCI1. Trauma is the most common cause of SCI, predominantly from falls and road traffic accidents. Damage to the spinal cord occurs both at the time of injury (primary) and in its aftermath (secondary). Effectively treating and preventing secondary cord injury, and managing complications associated with SCI, can make a significant improvement to patient outcomes.

Respiratory dysfunction is one of the most common medical complications, as well as the leading cause of reduced Quality of Life (QoL) and mortality, with literature indicating that 67% of individuals with a spinal cord injury present with respiratory complications in the acute stage.

The most common respiratory complications are: 1) atelectasis; 2) pneumonia; and 3) respiratory failure. A retrospective review of the patients with acute traumatic spinal cord injuries at C5-T5 level showed a higher prevalence of respiratory complications during the initial hospitalisation just after the injury and suggests the presence of previous respiratory disease, complete motor impairment

(AISA A-B) and coexistent thoracic trauma are a predictor of respiratory complications. Individuals with cervical and higher thoracic spinal cord injuries are more likely to develop respiratory complications, primarily due to diaphragm impairment.

Due to the above, patients have increased rates of infection, poor sputum clearance and inadequate humidification. These complications lead to prolonged admissions, admission to intensive care and considerable healthcare related costs. As such it is essential to develop new management protocols to reduce the occurrence of pulmonary complications

AIRVOTM (a form of non-invasive high flow oxygen therapy, HFOT), which delivers high flow heated and humidified oxygen and air via nasal cannula at a prescribed fraction of inspired oxygen and a maximum flow of 60 L/min, is an attractive alternative to conventional oxygen therapy. Previous studies have shown that HFOT therapy generates a flow-dependent positive airway pressure and improves oxygenation by increasing end-expiratory lung volume, thus suggesting a possible alveolar recruitment associated with high-flow therapy. Although widely used in other clinical areas across the NHS, HFOT delivered via the AIRVOTM system has yet to be evaluated in the spinal cord injury population.

Furthermore, HFNC oxygen therapy has been shown to improved swallowing function in a patient with dysphagia associated with respiratory-muscle paralysis following a SCI, further reducing the risk of aspiration and subsequent infection. It has been hypothesised that the use of HFNC prolongs the patient's apnoea tolerance time during swallowing and hence improves the timing of swallowing.

This study aims to explore the feasibility of using HFOT (delivered via AIRVOTM) therapy and compare to current treatment (conventional oxygen and humidification administration) for patients who have a spinal cord injury. The secondary outcomes will explore any provisional impacts on length of stay, requirement of admission to intensive care, antibiotic use, and physiotherapy requirements including use of cough augmentation e.g., Mechanical Insufflation - Exsufflation.

The results of this proof-of-concept study will be used to further develop local protocols and develop a multi-site research protocol for grant application.

Inclusion criteria

• Spinal cord injury between C4 and T4 (Include ASIA A-D)
• Admitted to spinal injury ward within 24-48hours of injury

Exclusion criteria

• Aged under 18 years
• 3 or more rib fractures or flail
• Sternal fracture
• Concomitant lung injury
• Unable to gain informed consent from participant
• Contra-indication to using high flow therapy e.g., undrained pneumothorax, facial fractures, nasal obstruction, CSF leak, suspected or confirmed base of skull fracture, active epistaxis or recent functional endoscopic sinus surgery.