The effect of abdominal functional electrical stimulation on blood pressure in people with high level spinal cord injury.

Study design: Single centre training study.

Objectives: To investigate, in a group of people with spinal cord injury (SCI), the effect of transcutaneous functional electrical stimulation of the abdominal muscles (abdominal FES) during cough training on blood pressure (BP), and how it is affected by injury characteristics and alters over time.

Setting: Laboratory and community.

Methods: Sixteen participants with SCI (C4-T5) underwent 25 of abdominal FES cough training (5 sets of 10 stimulated coughs) over 6 weeks as part of a previously published study on the effect of abdominal FES training on cough. Systolic BP (SBP), diastolic BP (DBP) and calculated mean arterial pressure (MAP) were measured at the completion of each set.

Results: Abdominal FES coughing resulted in an average ~30% acute increase in BP from initial resting BP across all sessions in almost all participants (p < 0.001). However, the increase in BP during abdominal FES coughs from rest reduced over the 25 sessions of training by ~35% for SBP, MAP and DBP (p = 0.024, p = 0.013 and p = 0.042, respectively). There was no meaningful change in resting BP over time (p = 0.935, p = 0.705 and p = 0.988, respectively). Overall, increases in BP during abdominal FES coughs were greatest for those with chronic injuries and cervical injuries.

Conclusions: Transcutaneous abdominal FES during cough training acutely increases BP. However, the magnitude of the increase is reduced after 25 sessions of training. Abdominal FES may offer a solution to combat orthostatic hypotension, but its effectiveness may diminish over time.