An Approach for Modeling of a Medical Equipment for the Estimation of Leakage Currents

An Approach for Modeling of a Medical Equipment for the Estimation of Leakage Currents

E. Zennaro G.L. Amicucci F. Fiamingo C. Mazzetti 

Department of Astronautics, Electrical and Energetics Engineering (DIAEE), Electrical Engineering Section, Università di Roma ‘La Sapienza’, Italy

Department of Safety Technology (DTS), Research, Certification and Verification Sector, INAIL – Istituto Nazionale per l’Assicurazione contro gli Infortuni sul Lavoro, Italy

31 December 2015
| Citation



In an operating theatre, electro medical equipment (EME) may fail and cause health hazards as the passing of a weak but hazardous current (leakage current) through the heart of the patient during surgical interventions. This occurs evidently during their use, when connected to the patient. The related values of leakage currents can be estimated by an electrical circuit model. To obtain the circuit of a surgical layout, the electrical models of medical location supply power system, human body and EME involved in a determined surgical intervention ought to be drawn. The present work focuses on the method to obtain the model of EME. The idea is to model by circuits each leakage current measurement set-up performed in accordance with the international standard IEC 60601-1. To assign the values to the model parameters, it is necessary to obtain also some information on the EME as the values of insulation impedances and the feasible leakage current paths inside it. The case of a commercial defibrillator is taken as an example to show the feasibility of the method. The comparison between the leakage currents simulated by the circuit and the ones measured is here presented. The agreement is satisfactory. An estimation of the model sensitivity due to the uncertainty in the knowledge of the parameters has been performed too, by using the Monte Carlo method. The extension of this approach to draw the model of other EME is also considered in view of the realization of a surgical layout circuit.


Applied part, defibrillator circuit model, electrical safety, medical equipment, microshock risk, leakage currents.


[1] Ferris, L.P., King, B.G., Spence, P.W. & Williams, H.B., Effect of electric shock on the heart. Transactions of the American Institute of Electrical Engineers, 55(5), pp. 498–515, 1936. doi:

[2] Dalziel, C.F. & Lee, W.R., Reevaluation of lethal electric currents. IEEE Transactions on Industry and General Applications, 5, pp. 467–476, 1968. doi: http://dx.doi. org/10.1109/TIGA.1968.4180929

[3] IEC/TS 60479-1, Effects of Current on Human Beings and Livestock – Part 1: General Aspects, International Electrotechnical Committee: Geneva, 2005.

[4] Friedlander, G.D., Electricity in hospitals: elimination of lethal hazards. IEEE Spectrum, 8(9), pp. 40–51, 1971. doi:

[5] Amicucci, G.L., Di Lollo, L., Fiamingo, F., Mazzocchi, V., Platania, G., Ranieri, D., Razzano, R., Camin, G., Sebastiani, G. & Gentile, P., Electrical safety during transplantation. Transplantation Proceedings, 42, pp. 2175–2180, 2010. doi: http://

[6] IEC EN 60601-1, Medical Electrical Equipment – General Requirements for Basic Safety and Essential Performance, 3rd edn, International Electrotechnical Committee: Geneva, 2007.

[7] Watson, A.B., Wright, J.S. & Loughman, J., Electrical thresholds for ventricular fibrillation in man. Medical Journal of Australia, 24(1), pp 1179–1182, 1973.

[8] Laks, M., Arzbaecher, R., Bailey, J., Berson, A., Briller, S. & Geselowitz, D., Will relaxing safe current limits for electromedical equipment increase hazards to patients? Circulation, 89(2), pp. 909–910, 1994. doi:

[9] Swerdlow, C.D., Olson, W.H., O’Connor, M.E., Gallik, D.M., Malkin, R.A. & Laks, M., Cardiovascular collapse caused by electrocardiographically silent 60-Hz intracardiac leakage current: implications for electrical safety. Circulation, 99, pp. 2559–2564, 1999. doi:

[10] Guidance for Industry and FDA Premarket and Design Control Reviewers; U.S Dept. of Health and Human Services, Food and Drug Administration, Medical Device UseSafety: Incorporating Human Factors Engineering into Risk Management, U.S Dept. of Health and Human Services, the  Food and Drug Administration: USA, 2000.

[11] Amicucci, G.L., Fiamingo, F. & Mazzetti, C., The Hospital Electrical Power Systems: Design and Operation Guidelines (in Italian Gli impianti elettrici ospedalieri: indicazioni costruttive e di utilizzo), “Gestire la sicurezza di impianti e tecnologie biomediche, Proposte per l’innovazione tecnologica in ambito sanitario”, Monografico ISPESL, Supplemento a Prevenzione Oggi n. 1, INAIL: Rome, 2008, ISBN 9788889415444.

[12] Amicucci, G.L., Fiamingo, F., Zennaro, E. & Poggi, L., Risk management for the protection and safety of electrical systems involving healthcare buildings (in Italian Gestione del rischio per la protezione e la sicurezza dei sistemi elettrici a servizio delle strutture ospedaliere), VGR 2012, Valutazione e Gestione del Rischio negli Insediamenti Civili ed Industriali, Pisa, October 3–5, 2012.

[13] IEC 60364-7-710, Electrical Installations of Buildings: Part 7–710, Requirements for Special Installations or Locations: Medical Locations, International Electrotechnical Committee: Geneva, 2002.

[14] EN ISO 14971, Medical Devices – Application of Risk Management to Medical Devices, 2nd edn., 2012. 

[15] Spalding, L., Carpes, W.Jr. & Batistela, N., A method to detect the microshock risk during a surgical procedure. IEEE Transactions on Instrumentation and Measurement, 

58(7), pp. 2335–2342, 2009. doi:

[16] IEC EN 62353, Medical Electrical Equipment – Recurrent Test and Test After Repair of Medical Electrical Equipment, International Electrotechnical Committee: Geneva 2008.

[17] Joint Committee for Guides in Metrology, Evaluation of measurement data – supplement 1 to the “guide to the expression of uncertainty in measurement” – propagation of distributions using a Monte Carlo method, Technical report, Joint Committee for Guides in Metrology, 2008.