Changes in superficial pressure and tissue oxygenation levels due to contractions elicited by intermittent electrical stimulation for the pre- vention of deep tissue injury

Deep tissue injury (DTI) is a severe type of pressure ulcer that commonly affects people with spinal cord injury (SCI). We have proposed the use of intermittent electrical stimulation (IES) as a novel preventative technique for DTI. The main goal of this study was to compare the changes in superficial pressure and tissue oxygenation generated by two different IES protocols: Continuous or Bursting IES. Experiments were performed in intact volunteers whose gluteus maximus muscles were stimulated bilaterally through surface electrodes. The volunteers sat in either a regular chair or a wheelchair with a specialized cushion. Surface pressure profiles were acquired with a pressure sensing mattress and magnetic resonance imaging was utilized to quantify the changes in oxygenation levels throughout the muscles. The results show that both Continuous and Bursting IES generate a significant reduction in pressure over the ischial tuberosities during stimulation when seated on a regular chair. Oxygenation levels were also significantly higher after the use of both protocols.