Spinal cord injury (SCI) results in the loss of function to not only voluntary motor control, but also to the regulatory systems that control bodily processes. Orthostatic (postural) hypotension (OH) is a common clinical feature in SCI patients, affecting up to 73% of patients with cervical spine and upper thoracic spine injuries during mobilisation and postural changes. This often results in symptoms of dizziness, light-headedness, fatigue and confusion, in turn limiting individual participation in physical rehabilitation and restricting progress towards regaining function and independence.
Therapeutic interventions are centred around ameliorating symptoms of OH; however, options for patients remain limited. Non-pharmacological treatments have had little success at treating hypotension in the long-term, while pharmacological interventions are used only when necessary as they may contribute to hypertension and even worsen episodes of autonomic dysreflexia, a life-threatening condition.
Functional Electrical Stimulation (FES) is one of the only interventions that has been shown to display some benefit in improving OH. Recently, stimulation of the lower limbs has been shown to acutely increase blood pressure in patients with SCI. Our recent projects have involved the use of FES applied over the abdominal muscles, termed abdominal FES, for SCI patients at risk of respiratory complications with promising results. As this same population is at risk of orthostatic hypotension, this study aims to determine whether abdominal stimulation can also be used to help this condition.
Based on our previous research, we believe that abdominal FES will increase blood pressure acutely during an orthostatic challenge in individuals with acute spinal cord injury, allowing for a longer time spent in a standing position. This will facilitate more effective rehabilitation, therefore improving quality of life and decreasing associated medical complications.
While tetraplegia is commonly associated with paralysis of all four limbs, paralysis also affects the major respiratory muscles, namely the diaphragm, abdominal and intercostal muscles. The reduction in respiratory function results in approximately 40% of tetraplegic patients requiring mechanical ventilation in the acute stage (first six weeks) of injury to support respiration. The use of mechanical ventilation increases lifelong morbidity and mortality, delays rehabilitation, results in longer hospital stays and costs the health care provider an additional $2,000 per patient per day.
Surface electrical stimulation of the abdominal muscles, termed Abdominal Functional Electrical Stimulation (FES), can contract the abdominal muscles, even when paralysed. We have shown that surface FES of the abdominal muscles, termed Abdominal FES, improves respiratory function in tetraplegia, and respiratory function is a known predictor of mechanical ventilation time. Dr McCaughey’s pilot work also shows that eight weeks of abdominal FES is a feasible method to reduce mechanical ventilation time in acute tetraplegia.
Despite these positive results, a lack of data from randomised control trials, and lack of a standard Abdominal FES protocol, has prevented this technology from being adopted as a standard clinical treatment.
This project will provide the first information on the effectiveness and cost-effectiveness of Abdominal FES to reduce mechanical ventilation duration in tetraplegia. In addition, it will provide detailed information about respiratory function and its impact on quality of life in tetraplegia.
This is an international collaboration brings together leading research and medical teams from: Neuroscience Research Australia, the Prince of Wales Hospital, Royal North Shore Hospital, Austin Health and Fiona Stanley Hospital in Australia; The Indian Spinal Cord Injury Centre and the Christian Medical College, Vellore, in India; The Queen Elizabeth National Spinal Injuries Unit and the University of Glasgow in Scotland; Middlemore Hospital in Auckland, New Zealand, and the University of Alberta and McMaster University in Canada.