Electrical stimulation of abdominal muscles for control of blood pressure and augmentation of cough in a C3/4 level tetraplegic
Authors: Taylor, P.N., Tromans, A.M., Harris, K.R. and Swain, I.D.
Journal: Spinal Cord
Objectives: Evaluation of a FES (Functional Electrical Stimulation) device for the relief of postural hypertension and augmentation of cough in a C3 ventilator-dependent tetraplegic.
Study design: A single case study.
Setting: A supra regional spinal unit in the UK.
Method: A dual channel stimulator was designed that allowed selection and initiation of two predetermined stimulation intensities using a chin controlled joystick. Two sets of 70 mm diameter electrodes were placed either side of the abdomen. Approximately 80 mA, 300 s, 40 Hz was required for assisted cough while about 40 mA was required for maintenance of blood pressure. After eating, the lower level stimulus is self-administered every 3 to 5 min gradually increasing the time between groups of burst to once every hour after 90 min.
Results: Following eating, a blood pressure of 60/45 mmHg was recorded. After five 1 s bursts of stimulation in quick repetition, this was increased to 133/92 mmHg. After 2 min blood pressure had fallen to 124/86 mmHg and to 93/66 after a further 4 min. The electrical stimulation was then repeated, returning the blood pressure to the previous higher level. Measurement of peak expiratory flow showed an increase from 275 l/min for an unassisted cough to 425 l/min when using the device.
Conclusion: The device is used every day. The user is now independent in coughing function and no longer requires suction or manual assistance. Maintenance of blood pressure has significantly improved his quality of life.
Preferred by: Ian Swain