University of Chicago
Electrical Trauma Program

As applications of electric power increased, it became clear that electric forces can cause lethal tissue injury. The first human fatality from an industrial accident apparently occurred in 1879 in Lyon, France (2). 

According to the Bureau of Labor Statistics, for the last decade, electrical injury has been responsible for an average of 320 deaths and over 4,000 injuries involving days away from work annually in the United States. It is the second leading cause of fatality in construction industry, and it consistently makes 5 to 6% of all occupational fatalities (3). Out of injuries caused by contact with overhead powerlines, 26.4 to 60.3 percent of cases resulted in over 31 days away from work (versus 18 to 20% for all other occupational injury and illness). 

Electrical injuries are very costly, not only for the victims and their families but for the employers and the society in general.  In a study by Dr. Ronald Wyzga of the Electric Power Research Institute, Palo Alto, California, electrical injuries’ cost to employers has been approximated as $15.75 million per case in direct and indirect costs (4). 

Figure 1. Typical surface appearance of electrical shock victim demonstrating thermal damage to skin at contact points on arm and chest wall.

Major high-voltage electrical trauma can produce one of the most devastating of physical injuries. Repeated debridements, amputations, and extensive rehabilitation are common. It is not unusual for a surgeon to debride viable tissue and then return 48 hours later to find most of the forearm muscles necrotic and an above-elbow amputation necessary (Fig. 1). Additional debridements may be repeated over several days. The condition of devitalized muscle can be further complicated by acute infection. Limb amputation rates for victims who experience direct electrical contact can be as high as 75% (5). In general, most victims who survive high-voltage electrical shock are left permanently disabled.

Mechanisms of Injury

To understand the effect of electric forces on biological systems, it is helpful to think in terms of bioelectric circuits. The major portion of cellular energy, for example, is expended in maintaining the difference in electrolyte concentrations (and secondary transmembrane potentials) across cell membranes. Ions leaking across membranes by electrodiffusion are pumped back in by ATP-driven pumps. The cell membrane properties which limit this leakage include resistance to ion transport, which in turn serves to conserve energy.

Strong electric fields can damage biological tissues by at least two mechanisms: Joule heating and electroporation (Fig. 2). When contact is through an electric arc, thermoacoustic blast force can significantly add to the injury. All these mechanisms lead to increased cell membrane permeability and energy depletion. In Joule heating, the passage of electric current through tissues causes their temperature to rise, leading to disruption of cell membranes at temperatures greater than 42°C, disruption of intramolecular bonds in proteins, with loss of conformation (denaturation) at slightly higher temperatures (<45°C), and denaturation of DNA at temperatures above 65°C. Heat damage is related to duration of exposure: The higher the temperature, the shorter the exposure time required for adverse effects. In most cases of high-voltage electrical shock (<10 kV), heat damage occurs instantaneously at contact points but requires 1-3 seconds to injure deeper tissues (6). Thermoacoustic blast can also cause a significant blunt trauma and associated fall injuries.

Electroporation, the breakdown of cell membranes by strong electric fields, has been first identified as an electrical injury mechanism in the mid-1980s (7). The molecular physics of the process is not completely understood, but in effect, the strong electric fields established within the cell membrane by large, induced transmembrane potential attract water into the membrane until large pores or defects form. Electroporation occurs in less than one millisecond, and most cell membranes rupture when more than 0.8 to 1 V of transmembrane potential is imposed.
The pattern of tissue injury is also a consequence of the body's electrical properties. All tissues except the skin are relatively good conductors. When a victim comes into contact with a high-voltage power source (>200 V), the epidermis is usually destroyed by heat within milliseconds. Large currents can then pass and produce tissue damage, especially to skeletal muscle and nerve. 

The most challenging aspect of acute treatment is that the tissue in the electric current path—unless there has been significant heating—may appear grossly normal. Typically, it is at least 1 to 3 days before the true extent of damage can be recognized. Furthermore, healthy skin and fat often conceal injured muscles, nerves, and bone. Thus, it is very difficult to accurately diagnose and localize tissue damage scattered throughout the current path before irreversible cellular degeneration has occurred. This is why it is so critically important to develop new imaging techniques that would allow surgeons to immediately recognize the full extent of tissue injury and take appropriate steps at clinical management.
Because normal physiology involves so many applications of electrical forces, ranging from neuromuscular signaling to coordination of wound healing, biological systems are very vulnerable to application of supraphysiologic electric fields. Therefore, even when the injury doesn't involve any visible tissue damage, electrical shock survivors may be left with significant consequences. 

It is very important that families and co-workers of injured persons understand that even with no visible burn, survivors may be faced with long-term muscular pain and discomfort, fatigue, problems with peripheral nerve conduction and sensation, inadequate balance and coordination, and other symptoms. 

Electrical injury often leads to problems with neurocognitive function, affecting speed of mental processing, attention, concentration, and memory. In addition, as any traumatic experience in a life-threatening situation, electrical injury may result in post traumatic psychiatric disorders which can be as life-changing as a major physical deformity. It does require a supportive environment for the victims to return to productive life and normal family and social functioning.
 
 

Figure 2. Structural damage to cell membranes, particularly of muscle and nerve, is a principal mechanism of tissue destruction in electrical shock.

A Center for Electrical Injury Treatment and Clinical Research

To advance the care of electrically injured patients, the University of Chicago Hospitals have established a clinical and research program for electrical shock victims. The Electrical Trauma Program, directed by Raphael C. Lee, MD, ScD, is dedicated to understanding the mechanisms and manifestations of electrical injuries and to developing therapeutic interventions.

To date, ETP researchers have determined the biophysical mechanisms of tissue damage in electrical shock; obtained FDA approval for clinical testing of a drug which promises to reduce tissue loss; published a controlled study of neuropsychological symptoms after electrical shock; correlated accident parameters with injury patterns; and identified accident parameters associated with the development of psychiatric disorders. Further studies are underway.

Electrical injury patients admitted to the University of Chicago Hospitals undergo rapid and thorough diagnostic imaging studies to guide standard clinical therapy. As in other burn units, spine fractures and severe electrolyte disorders are treated as first priorities. Muscle compartment fluid dynamics are assessed during resuscitation. Rapid medical and surgical intervention to reduce elevated pressures (to restore blood perfusion) and achieve timely debridement and wound coverage are the mainstay of initial therapy.  In June 2000, Electrical Trauma Program has established a collaboration with St. Mary Medical Center, Hobart, IN, which will serve as a primary referral center for electrical injury victims in Indiana and Michigan in vertical integration with the University of Chicago ETP program.

Advanced Diagnostic Methods: To diagnose occult damage to muscle, nerve and bone - which may later be aggressively treated surgically - Electrical Trauma Program collaborators from the Department of Radiology are employing new strategies in magnetic resonance (MR) imaging to locate and quantify tissue injury and monitor response to therapy. A very low field Instrumentarium MEGA-4 (0.1 T) unit has been installed in the emergency ward to permit rapid study before a patient is transported to the intensive care unit. The 0.1 T unit permits higher sensitivity to tissue protein - water interactions (thus, edema), and it allows simultaneous use of resuscitation equipment during imaging. In the laboratory, more advanced strategies are being developed: MR angiography can both detect damage to vasculature and monitor tissue perfusion; and MR sodium imaging, by distinguishing changes in extra-cellular and intra-cellular ion concentrations, can locate and quantify cell membrane damage in tissues. MR facilities are located within the emergency ward.

The National Institutes of Health have funded research by Dr. Lee and Dr. Gregory Karczmar (Department of Radiology) to determine relative contributions of direct electrical and thermal damage in electrical injury using MR spectroscopy.

Figure 3. SPECT image of patient in Fig. 1 showing damaged deltoid muscle hidden beneath undamaged skin.

Positron emission tomography (PET) and single photoelectron emission computed tomography (SPECT) are also being employed (Fig. 3) to map and monitor tissue injury. Richard Reba, MD, Malcolm Cooper, MD, and Chin-Tu Chen, PhD, of the University's Franklin Memorial Research Institute, have implemented protocols for measuring tissue perfusion, muscle membrane integrity, and glucose metabolism. Soon to be routinely performed at the bedside, these techniques employ radiotracers to reflect physiological conditions including cellular metabolism, blood flow, and cell membrane integrity.

Nerve injuries are practically unavoidable following electrical shock. Because of the complex composition of nerve tissue, the pattern of injury that often results from electrical shock is more complex than commonly used neurological tests allow to detect. To more accurately describe the electrical nerve injury we have adapted more sophisticated spectral analysis techniques. We have found that these studies are very helpful in making diagnosis and planning therapy.

Another aspect of the multidisciplinary clinical research program is the complete neuropsychologic, psychiatric, and social-emotional evaluation of the patients. Kathleen Kelley, MD, Neil Pliskin, PhD, Joseph Fink, PhD, and Gregory Meyer, PhD, from the Department of Psychiatry, have begun a longitudinal study of acute psychiatric ET patients. Their assessments are integrated with findings of the peripheral nervous system evaluation, in-depth chart review to clarify the degree and functional consequences of CNS damage, its correlates, and predisposing factors. The rigorous neuropsychological evaluation of electrical injury patients admitted in the program has provided important insight into effective strategies for rehabilitation of patients with CNS injury.  The first article by N. Pliskin et al describing neuropsychological symptom presentation after electrical injury was published in 1998 in the Journal of Trauma (8).  To understand the risk factors for development a psychiatric disorder following electrical injury (such as depression or posttraumatic stress disorder), Dr. Kathleen Kelley and Tatiana Tkachenko began to analyze which injury circumstances are statistically associated with the increased likelihood of subsequent emotional illness (9), the information that will allow to develop more effective early intervention strategies to prevent or mitigate psychiatric pathology.

Figure 4.

Research: Ultimately, however, the problem of electrical trauma will not be addressed meaningfully until effective techniques to seal membranes and recharge cells with ATP are developed. For this reason, clinical research is tightly coupled to a multidisciplinary experimental and theoretical research effort coordinated by Jurgen Hannig, PhD. Practical strategies (Fig. 4) to reverse electrically produced tissue damage under controlled laboratory conditions have yielded promising results involving the use of membrane-active polymers which stabilize membranes and initiate sealing (10).

Rehabilitation: The electrical injury has more than one victim. Co-workers and family members are often affected as well. Successful therapy has multiple components including successful re-integration into the workplace. Dr. Mary Capelli-Schellpfeffer has led the ETRP efforts to find most effective strategies for the occupational and social rehabilitation of electrical trauma survivors and facilitate their return to full productive lives. Dr. Mary Lawler provides consultation and treatment concerning the patients' physical rehabilitation.

In 1999, Dr. Kathleen Kelley and other ETP researchers in collaboration with Peter Campbell and John Christiansen of Argonne National Laboratory have received a grant from the U.S. Department of Energy to develop a virtual reality treatment for patients with posttraumatic stress disorder after electrical injury that is known to prevent electricians from successful returning to work. A survey of typical electrical injury scenarios has been conducted, and the ANL computer scientists are currently working on the VR software development. Once the software is developed, clinical trials will be conducted to evaluate the effectiveness of this new treatment in electrical injury rehabilitation. 

Prevention: Electrical Trauma Program researchers have been exploring the ways to prevent injuries from occurring as well as to reduce long-term effects of injuries. 

Dr. Mary Capelli-Schellpfeffer is investigating electric arc mediated exposures and thermoacoustic blast injury. Her project "Electric Arc Injury Parameters and Prevention" has been funded by the National Institute for Occupational Safety and Health. Dr. Capelli-Schellpfeffer also collaborates with the IBEW-NECA National Joint Apprenticeship and Training Committee for the Electrical Industry (NJATC) and the IEEE electrical safety community. 

In collaboration with local IBEW chapters 176 and 15, Tatiana Tkachenko and Dr. Kathleen Kelley have started attitudinal studies of electrical workers in order to learn how electricians understand electrical injury and their occupational risks, as well as to describe any cultural patterns of their coping with injuries that may affect rehabilitation success (11).

International Collaborations: A significant aspect of the Electrical Trauma Program mission has always been the development of international cooperation in electrical injury prevention and research.  Over the past decade, the ETP has enjoyed a productive working relationship with Shanghai Power Hospital, a premier electrical trauma treatment center in the People's Republic of China.  This collaboration culminated in the gathering of the 3rd International Conference on Occupational Electrical Injury and Safety in October of 1998 in Shanghai.  The Conference Proceedings have been published in the Annals of the New York Academy of Sciences, Volume 888, 1999.

Other important international collaborators have included University of Alberta Burn Center, Canada;  Lin Kou Burn Center, Taipei;  The Ministry of Health of the Republic of Belarus; and Charles University Burn Center, Prague, Czech Republic.

Sponsors:  The electrical injury research project at the University of Chicago has been sponsored by the National Institutes of Health, Electric Power Research Institute, the United States Department of Energy, the National Institute for Occupational Safety and Health, as well as major industrial sponsors including Commonwealth Edison, The Empire State Electric Energy Research Corporation, New York State Electric and Gas, Niagara Mohawk Power Corporation, Northeast Utilities, Public Service Electric & Gas, Public Service of Oklahoma, the Amoco Foundation, the Shell Foundation, and Wisconsin Electric Power Company.

Referral Information:  The services of Electrical Trauma center are available to electrical shock survivors and referring physicians. Severely injured victims should be evaluated and stabilized at the nearest trauma center first. For patients in Indiana, St. Mary Medical Center in Hobart, IN, has been designated by the ETP as a primary referral center.  Because timing is critical in treating these patients, the Electrical Trauma Program relies on transport coordination by the University of Chicago Aeromedical Network (UCAN), which can be reached at 800-621-7827.

To refer a patient for an ETP evaluation please contact Mary Ann Payton, RN, University of Chicago ETP Clinical Coordinator, at 773-834-2816 or at mpayton@surgery.bsd.uchicago.edu or by fax at 773-702-0661.  At St. Mary Medical Center please contact Tatiana Tkachenko, ETP Coordinator, at 219-947-6023 or ttkachenko@ancilla.org or by fax at 219-947-6052.

For additional research information on the Electrical Trauma Program, or if you wish to consider making a tax-deductible contribution to support the Electrical Trauma Program please contact Dr. Raphael C. Lee at 773-834-2816 or 219-947-6023.

References

1. Faraday M. Experimental Researches in Electricity. London: R Taylor & Francis; 1839, 1855; Vols. 1,3.
2. Jex-Blake AJ. The Goulstonian lectures on death by electric currents and by lightning. BMJ 1913;11:425-552.
3. United States Department of Labor. Bureau of Labor Statistics. Census of Fatal Occupational Injuries, 1992-99.
4. Wyzga RE, Lindroos W.  Health implications of global electrification. Annals of the NYAS, Volume 888, pp.1-7.
5. Rouse RG, Dimick AR. The treatment of electrical injury compared to burn injury: a review of pathophysiology and comparison of patient management protocols. J Trauma 1978; 18; 43-47.
6. Tropea BI, Lee RC. Thermal injury kinetics in electrical trauma. J Biomech Engr 1992; 114:241-250.
7. Lee RC, et al. Role of cell membrane rupture in the pathogenesis of electrical trauma. J Surg Res 1988; 44: 670-682.
8. Pliskin NH, Capelli-Schellpfeffer M, Law R, Malina A, Kelley K, and Lee RC. Neuropsychological symptom presentation after electrical injury. The Journal of Trauma, Vol. 44, No. 4, pp. 709-715.
9. Kelley KM, Tkachenko TA, Pliskin NH, Fink JW, Lee RC. Life after electrical injury: Risk factors for psychiatric sequelae. Annals of the NYAS, Volume 888, pp. 356-363.
10. Lee RC, River LP, Pan F-S, Ji L, Wollman RL. Surfactant-induced sealing of electropermeabilized skeletal muscle membranes in vivo. Proc Natl Acad Sci USA 1992; 89: 4524-4528.
11. Tkachenko TA, Kelley KM, Pliskin NH, Fink JW. Electrical injury through the eyes of professional electricians. Annals of the NYAS, Volume 888, pp. 42-59.