Inter-electrode tissue resistance is not affected by tissue oedema when electrically stimulating the lower limb of sepsis patients

William K. Durfee, Joseph R. Young, Hans F. Ginz

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Abstract

ICU patients typically are given large amounts of fluid and often develop oedema. The purpose of this study was to evaluate whether the oedema would change inter-electrode resistance and, thus, require a different approach to using non-invasive electrical stimulation of nerves to assess muscle force. Inter-electrode tissue resistance in the lower leg was measured by applying a 300 μs constant current pulse and measuring the current through and voltage across the stimulating electrodes. The protocol was administered to nine ICU patients with oedema, eight surgical patients without oedema and eight healthy controls. No significant difference in inter-electrode resistance was found between the three groups. For all groups, resistance decreased as stimulation current increased. In conclusion, inter-electrode resistance in ICU patients with severe oedema is the same as the resistance in regular surgical patients and healthy controls. This means that non-invasive nerve stimulation devices do not need to be designed to accommodate different resistances when used with oedema patients; however, surface stimulation does require higher current levels with oedema patients because of the increased distance between the skin surface and the targeted nerve or muscle.

Original languageEnglish (US)
Pages (from-to)227-231
Number of pages5
JournalJournal of Medical Engineering and Technology
Volume38
Issue number4
DOIs
StatePublished - May 2014

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Keywords

  • Electrical stimulation
  • Oedema
  • Tissue resistance

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