The Effect of Abdominal Functional Electrical Stimulation on Blood Pressure Control in Spinal Cord Injury

There are over 200,000 new cases of spinal cord injury globally each year, with more than 70% of these injuries occurring at the level of the cervical spine and upper thoracic spine (C1-T5). Injuries to these levels result in alteration to the sympathetic nervous system which causes dysregulation to blood pressure control, can lead to swings in blood pressure, and most commonly hypotension especially when seated upright or standing. We have shown that surface Functional Electrical Stimulation (FES) of the abdominal muscles, termed Abdominal FES, can improve respiratory function and may assist weaning from mechanical ventilation in spinal cord injury. During these studies we also observed an increase in systolic blood pressure. Eighteen participants will be recruited to this single centre randomised, placebo controlled, trial. Participants with a spinal cord injury in the region C1-T5 will be recruited between 6 weeks and 6 months post injury. Nine participants will be randomly allocated to receive Abdominal FES and 9 will receive a placebo. In the Abdominal FES group, Abdominal FES will be applied for 45 minutes per day, 5 days per week, for 2 weeks. Specifically, Abdominal FES will be delivered, via electrodes placed over the posterolateral surface of the abdomen. The stimulation amplitude will be set to cause a strong visible muscle contraction (usually 30-60 mA) at a frequency of 50Hz and 350 microseconds pulsewidth. Stimulation amplitude will be evaluated every 5 minutes to ensure that stimulation is still tolerable and causing a suitable muscle contraction. Stimulation will be applied by a local physiotherapist. A daily training diary will be kept to monitor compliance.