Since the mid-1960s, considerable research has been directed at evaluating the effects of exogenous electrical currents on healing of chronic wounds, which, unlike acute wounds, do not heal spontaneously within a predictable time frame and are frequently unresponsive to many standard treatment interventions. Currently, treatments available to patients with chronic wounds are mostly influenced by federal and regional insurance authorities who more and more base reimbursement decisions on treatment effectiveness, which they in turn establish by determining the strength of evidence derived from basic science and clinical research trials.
The objectives of this chapter are to (1) describe the endogenous bioelectric system of the integument and its influence on wound repair; (2) define basic terminology related to the use of exogenous, conductively (capacitively) coupled electrical currents (CCECs) for enhancing chronic wound healing; (3) review basic science research and discuss reputed mechanisms by which CCEC accelerates wound healing; (4) review clinical research evidence that supports the use of CCEC as an efficacious intervention for healing chronic wounds; (5) describe clinical methods of applying CCEC to facilitate wound healing; and (6) identify precautions and contraindications for the use of CCEC for wound healing.
Endogenous Electrical Currents
Several organs of the body that play vital roles in preserving or protecting life generate natural bioelectric currents that may be measured and analyzed to determine if the organ is functioning normally. Examples of these endogenous currents include the transmembrane voltages found in cell membranes and the action potentials and electrical impulses carried along peripheral nerves to synapses in skeletal muscle and along the vagus nerve to facilitate cardiac muscle contraction. Measurable currents are also found in the skin (the largest organ of the body) and wounds, as well as in the cells that facilitate wound repair. This section discusses the biologically inherent currents that are associated with healing.
Naturally Occurring Electric Fields in Wounds–Endogenous Wound Electric Fields
A Brief History of "Animal Electricity"
Animal electricity was among the most important scientific discoveries in the 18th and 19th centuries. In 1794 Luigi Galvani demonstrated that when the cut end of a frog sciatic nerve from one leg touched the muscles of the opposite leg, muscles in that leg contracted.1,2 In the same year, an anonymously written paper reported that when the excised leg of a frog was brought into contact with an exposed spinal cord, the other leg twitched.3 We now know that the muscular contraction occurred as a result of the electrical currents of injury from the damaged nerve and skinned leg. Galvani thus provided evidence for "animal electricity." In 1831, Carlo Matteucci was able to confirm Galvani's findings.4 He showed that an injured muscle released a small electric current and that, in Galvani's demonstration, it was this electric current that induced the muscle contraction in the ...