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Electrical Safety During Transplantation

G.L. Amicucci, L. Di Lollo, F. Fiamingo, V. Mazzocchi, G. Platania, D. Ranieri, R. Razzano, G. Camin,G. Sebastiani, and P. Gentile

ABSTRACT

Technologic innovations enable management of medical equipment and power supplysystems, with improvements that can affect the technical aspects, economics, and quality ofmedical service. Herein are outlined some technical guidelines, proposed by IstitutoSuperiore per la Prevenzione e la Sicurezza del Lavoro, for increasing the effectiveness ofthe power supply system and the safety of patients and surgeons in the operating room,

with particular focus on transplantation. The dependence of diagnoses and therapies onoperation of the electrical equipment can potentially cause great risk to patients.Moreover, it is possible that faulty electrical equipment could produce current that mayflow through the patient. Because patients are particularly vulnerable when their naturalprotection is considerably decreased, as during transplantation or other surgery, powersupply systems must operate with a high degree of reliability and quality to prevent risk,and must be designed to reduce hazards from direct and indirect contact. Reliability of thepower supply system is closely related to the quality of the project, choice of materials, andmanagement of the system (eg, quality and frequency of servicing). Among the proposedguidelines, other than normal referencing, are (1) adoption of a monitoring system toimprove the quality of the electrical parameters in the operating room, (2) institution ofemergency procedures for management of electrical faults, (3) a procedure for manage-ment of fires in the operating room, (4) and maintenance interventions and inspections ofmedical devices to maintain minimal requirements of safety and performance.

DURING TRANSPLANTATION, electrical safety is

fundamental, and each member of the operating staffmust be able to recognize and manage the associatedspecific risks.1 In some medical procedures, low current issufficient to cause respiratory paralysis (10 mA) or poten-tially fatal ventricular fibrillation (20 mA). The low-

resistance pathway via skin penetration and decreasedpatient defenses because of medication or anesthesia in-crease the risk of electric shock under faulty conditions. Thegreatest danger is associated with interrupted equipment-

to-earth connections.During open heart surgery and when catheters are in use,the risk is increased. It is necessary to minimize leakage ofcurrent that may flow into the patient. Current as low as 10A through the heart to the earth may be fatal, and the riskincreases considerably at 50 A (microshock).

During transplantation, major risks to patient safety due

to electrical hazards include (1) macroshock and micro-shock due to direct or indirect contact; (2) voltage inter-ruption that affects life-supporting medical equipment; (3)

deterioration in performance of medical equipment be-cause of a poor power supply; and (4) fire or explosion dueto electrical ignition. The first risk can be decreased bydesigning the power supply system to avoid direct orindirect contact; the second risk is suppressed by designingthe power supply system to have a high level of reliability,not comparable to that of common systems; the third risk isresolved if the power supply is of high quality, with limited

From Istituto Superiore per la Prevenzione e la Sicurezza del

Lavoro, Dipartimento Tecnologie di Sicurezza, Rome (G.L.A.,L.D.L, F.F., V.M., G.P., D.R., R.R.), Azienda Provinciale per i

Servizi Sanitari Trento, Trento (G.C.), Azienda Sanitaria della

Provincia Autonoma di Bolzano, Comprensorio Sanitario di Bres-

sanone, Ripartizione Tecnica, Bressanone (G.S.), and Comando

Nazionale Vigili del Fuoco, Rome (P.G.), Italy.

Address reprint requests to Giovanni Luca Amicucci, Istituto

Superiore per la Prevenzione e la Sicurezza del Lavoro, Diparti-

mento Tecnologie di Sicurezza, Via Fontana Candida 1,00040

Monteporzio Catone, Rome, Italy. E-mail: giovanniluca.amicucci@

ispesl.it

2010 by Elsevier Inc. All rights reserved. 0041-1345/see front matter360 Park Avenue South, New York, NY 10010-1710 doi:10.1016/j.transproceed.2010.05.133

Transplantation Proceedings, 42, 21752180 (2010) 2175

mailto:giovanniluca.amicucci@ispesl.itmailto:giovanniluca.amicucci@ispesl.itmailto:giovanniluca.amicucci@ispesl.itmailto:giovanniluca.amicucci@ispesl.it

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variability in voltage and frequency, and negligible distor-tion of the current waveform; and the fourth risk requiresapplication of electrical components that are compliantwith the ATEX Directive (from the French ATmospheresEXplosible).

METHODS

Health care locations are categorized as group 0, 1, or 2 by the IEC

60364-7-710 (International Electrotechnical Commission, Geneva,Switzerland).2 Group 0 includes locations in which no medicalelectrical equipment with applied parts are used. Group 1 includes

locations in which medical electrical equipment with applied partsmay be used outside or inside any part of the body except thecardiac area. In group 1 locations, discontinuity of supply is not athreat to human life. Group 2 includes locations for performance of

intracardiac procedures, operations, or vital treatment in whichdiscontinuity (failure) of the supply can cause danger to life ornecessary repetition of the examination or treatment. In group 1

and 2 medical locations, the patient area is defined as any place in

which a patient could come into contact, intentionally or not, withanother electrical equipment or conductive element, bringing the

ground reference voltage, or other persons touching such elements.

Reduction of Risk of Macroshock or Microshock

To reduce the risk of direct or indirect contact and to preventuntimely voltage interruption due to the action of residual-current

devices, 2 special safety requirements should be applied:13 (1) ingroup 2 locations, connection of the electrical equipment to amedical IT system (isolated power supply) in the patient area, and

(2) in group 1 and 2 locations, installation of a supplementaryequipotential bonding to eliminate even small but potentiallydangerous voltage due to current leakage or faults at the main

isolation.

In the event of an earth fault at the isolated power supply, thefault current is negligible, minimizing the hazards from touch

voltage. The power system may continue to function without an

unannounced trip, which is dangerous to patients on life-supportequipment. A second fault would be dangerous because high faultcurrent passing through the circuits will cause opening of the

protection; thus, patients are potentially endangered first by thehigh current and second by the voltage interruption. Thus, aninsulation monitoring device that emits audible and visual alarms

for the first fault, and for its disconnection from the isolated powersupply and for overload and high temperature of the insulationtransformer, is placed either within or adjacent to the group 2location.

Reduction of Risk of Voltage Interruption

To avert untimely voltage interruption due to lack of the electricgrid, it is necessary to have a standby independent power system

(safety power supply service), taking into account the permissiblechangeover time according to standard IEC 60364-7-710,2 asfollows: (1) Safety power supply service with changeover time no

more than 1.5 seconds (short interruption) that is energized to feedthe equipment of interest for a minimum of 3 hours, for example,operating table lights and other essential lights such as on endo-

scopes, and for vitally important equipment. The 1.5-secondchangeover time also applies to no-break supplies required when a

vital treatment involves use of medical equipment. (2) Safety powersupply service with changeover time of 1.5 to 15 seconds (medium

interruption time) that is energized to feed the equipment of

interest for a minimum of 24 hours. This includes electricalequipment for the gas supply, compressed air, vacuum supply,anesthetic exhaust, medical devices of vital importance in group 2locations, and fire alarms, fire-extinguishing systems, ventilating

systems for smoke extraction, and selected lifts for firefighters. (3)

Safety power supply service with changeover time of more than 15seconds (long interruption) that is energized to feed the equipment

of interest for a minimum of 24 hours. This includes sterilizationequipment, and technical building installations such as air condi-tioning and ventilation systems, building services, waste disposal

systems, and storage battery chargers.

Reduction of Risk From Poor Quality of Power Supply

When the voltage of one or more line conductors at the maindistribution board has decreased by more than 12% of the nominal

value of supply voltage for longer than 3 seconds, a safety powersupply source should be connected within 15 seconds to thoseservices that need it. However, it is not sufficient to intervene when

there are dips in voltage. In addition, variations in frequency anddistortion of absorption must be avoided. High-frequency surgicalequipment includes switching power suppliers, transformers, and

diodes to raise the voltage and high-frequency oscillators, allcomponents that introduce current distortion and voltage spikes.For such kinds of disturbances, potentially capable of compromis-ing the functioning of other medical equipment connected to the

same circuit without sufficient immunity, it is possible to adapt forthe emitting equipment dedicated socket-outlets with suitablefilters.

Reduction of Risk of Fire From Electrical Ignition

During transplantation, in the operating room, the 3 elements ofthe fire triangle are combustible materials, a heat or ignition

source, and an oxidizer-enriched environment. Operating roomscontain combustible materials of all types including patient andstaff linens, preparation agents and solutions, skin degreasers,tinctures, aerosols, ointments, collodion, petrolatum, paraffin,

white wax, plastic and rubber products, blood pressure and tour-niquet cuffs, gloves, stethoscope tubing, anesthesia components,breathing circuits, masks, airway and endotracheal tubes, and

patient body tissues and hair. The oxygen-enriched environment isdue to inhalation anesthesia (oxygen or nitrous oxide) or in thecase of regional or local anesthesia, supplemental oxygen to

counteract the respiratory-depressant effects of sedation.According to the ATEX Directive, if there is the possibility of

creating an explosive atmosphere, the electrical components andpower supply system should be used such that the atmosphere is

not ignited. When the electrical components and the power supplysystem are in compliance with the relevant directive, the risk of fireor a blast is dramatically decreased. There remains only the

possibility of ignition due to equipment that requires high energy tooperate, which cannot be avoided. Recourse to specific procedurescan reduce the risk.

RESULTS

Increase in Quality of Power Supply Using a

Monitoring System

To reduce the risk of deterioration in the performance ofmedical electrical equipment due to poor quality of thepower supply, it is possible to adapt information technology

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to build automated solutions for a monitoring system thathelps, in real time, to supervise and check the performanceof the more important components of the power supplysystem. Monitoring of such components to find anomaliesor failures in real time facilitates management of ordinary

and extraordinary maintenance, thus reducing unexpectedcosts and unplanned stops due to malfunction.This is possible because many components of the power

supply system (eg, UPS [uninterrupted power supply] anddiesel generator) have standard ports (RS 232, IEEE 488, andUSB) through which data can be obtained about the mostimportant parameters of the component. For older compo-nents or those that do not have a communication port, anacquisition system board with sensors can be used for the inputand communication ports for the output. For the simplepurposes and performances that they serve, such boards mayalso be inexpensive. Moreover, it is possible to adapt networkanalyzers such as those used for building automation applica-

tions to measure the quality of the electrical parameters in thekey points of the power supply system.The monitoring system is divided into 2 subsystems con-

nected by a LAN (local area network). One subsystem iscomposed of a set of sensors interconnected to the maincomponents, which acquire electrical parameters and otherimportant data such as the residual charge of the UPS batterypack, the level in the fuel tank of the electric generator, andthe open/closed status of the circuit breakers. The othersubsystem is composed of the central unit for data acquisitionand elaboration, and alarm notification, which is placed ineither the operating room or an adjacent location.

The monitoring system should also have actuation capa-bility, in which switches and interrupters are used viaremote control, representing a complete control system.Thus, the central unit would be able to change the topologyof the power supply system, choosing the safety powersupply services and seeking temporary solutions, such asredirection of circuits, insertion of filters, or disconnectionof the part of the main board where a fault is located, tomanage possible electrical failure.

Electrical Emergency Procedures for failure of Power

Supply System in Operating Room

Notwithstanding the adopted applications, it is still possiblethat a fault in the power supply circuits will cause voltageinterruptions. When this happens during transplantation orany other surgery, it is necessary to fix the status of thepatient as best as possible and to quickly restore the voltage.To be successful in restoring the voltage, adequate knowl-edge of the power supply system is necessary including thespecific response of each subsystem to failure. Reliability ofthe power supply system is assessed by weighting its com-patibility with the requirements of essential medical ser-vices. As compared with normal electrical failures that donot require special urgency or actions beyond ordinarymaintenance, suspension of power to an operating room,especially during transplantation, is an electrical emer-gency.

Reduction of the risk during emergencies is possible in 2ways, either by decreasing the probability that the unwantedevent will happen or reducing its harmful effects. Thus,suitable emergency procedures can be prepared to reduceto a minimum the hazard created by power faults, either

interruption of the external power source or failure of theelectrical circuits internal to the medical institution. Suchprocedures together constitute the Risk and EmergencyManagement Program of the medical institution. Any pro-cedure shall characterize unequivocally the emergencysituation, beginning with the identifiable signs, and fore-see a coherent use of existing resources to obtain optimalbenefits.

The following lists the steps common to each emergencyprocedure: (l) locate and recognize the fault so that it ispossible to choose the relevant emergency procedure; (2)check availability of the safety power supply services; (3)make power provisions for the duration of the emergency

condition; (4) have a suitable alarm procedure to alert forthe need for external assistance (eg, to firefighters foradditional diesel generators); (5) repair the fault; and (6)restore the normal power supply. Insofar as these steps, thefollowing considerations are proposed: careful managementof an emergency reduces its harmful effects; emergencymanagement is based on immediate recognition of theevent; and personnel who operate the power supply must behighly qualified.

In the emergency procedures, the following factors areimportant. A synthetic board with the steps outlined forqualified operators must be in place before the detailedprocedure; unambiguous description of particular emer-gency situations should make it impossible to execute stepsthat are relevant to unrelated faults; all possible conse-quences of involved medical services and locations must belisted so that the health staff and patient at risk are warnedand informed about each action to be taken; and possibledifficulties that can arise during restoration of normalpower must be described.

Management of Fire in Operating Room During

Transplantation

If a fire occurs, different layers of in-depth defense providea response proportionate to the magnitude of the incident.Fires are extinguished by separating combustible materialsfrom the oxidizer and, to a lesser extent, by cooling thereactants. After prevention, the first step in defense is theportable fire extinguisher. Various types of fire extinguish-ers are intended for different types of fires. Proper selec-tion, maintenance, and training in their use are essential.Operating rooms are equipped with class A, B, and Cextinguishers (carbon dioxide), which can be used in all 3types of fire (Fig 1).

Delay in making a decision about fighting the fire orevacuation may put the patient at extreme risk. Dependingon what is burning, toxic products such as carbon monoxide,ammonia, cyanide, isocyanates, and hydrogen chloride canbe released by combustion of various materials.

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To manage fires in the operating room during transplanta-

tion, the following procedure is suggested. First, recognize the

signs of fire early. Second, halt the procedure, sound the

alarm, and, if possible, remove the burning material from

contact with the patient. Third, make appropriate attempts to

extinguish the fire. Burning drapes or other materials shouldbe placed on the floor or in another location where they

cannot ignite other materials. If any burning materials cannot

be removed from contact with the patient or if the fire is not

quickly extinguished or continues to spread, a fire extinguisher

should be used. Fourth, follow an evacuation protocol when

medically appropriate. If the decision is made to evacuate the

operating room, the gas supply valves for the room should be

turned off. If the decision is made to remain in the operating

room, at least the sources of supplemental oxygen directed at

the fire should be turned off. Fifth, provide post-fire care to the

patient.

Safety of Medical Devices Used During Transplantation

Basic safety and essential performance of medical, active

implantable, and in vitro diagnostic medical devices must be

guaranteed. Satisfactory performance of such equipment is

in the interest of patient and operator safety. The CE mark

(Conformit Europenne [European Conformity]) guaran-tees compliance of suitable essential requirements of per-

formance and safety standards, which are listed in the

appendices to the relevant directive: Directive 93/42/EEC,4

amended by Directive 2007/47/EC,5 concerning medical

devices; Directive 90/385/EEC,6 amended by Directive

2007/47/EC,5 concerning active implantable medical de-

vices; and Directive 98/79/EC,7 concerning in vitro diagnos-

tic medical devices.

The devices must be designed and manufactured so that

when used under the appropriate conditions and for the

intended purpose, they will not compromise the clinical

Fig 1. Fire extinguisher suitability and effectiveness in the operating room. Faces indicate the effectiveness of an extinguisher in

various classes of fire: black, suitable; gray, unsuitable.

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condition or safety of the patient or the safety and health ofthe users or other persons. The manufacturer must ensure

that any risk associated with use of a device is acceptablewhen weighed against the benefits to the patient. Thedevices must conform to a high degree of health and safety

protection. The end user must be informed by the manu-facturer of any residual risk. Devices with a measurementfunction must be designed and manufactured so as toprovide sufficient accuracy and reliability within appro-priate limits, taking into account the intended purpose.According to cited Directives, Member States of theEuropean Union are directed to take the necessary stepsto record and evaluate information about incidents in-

volving devices.Characteristics and performance must not be adversely

affected to such degree that the clinical condition and safetyof patients and other persons are compromised during thelifetime of the device when it is subjected to the stresses

that can occur during normal use, as indicated by themanufacturer. Maintenance is fundamental and compul-sory for preservation of device characteristics and perfor-mance. Each device must be accompanied by the informa-tion needed to use it, taking into account the training andknowledge of potential users. Moreover, the manufacturermust provide all information needed to verify whether

the device is properly installed and can operate correctlyand safely, and details of the nature and frequency ofmaintenance and calibration needed to ensure that thedevice always operates properly and safely. If mainte-nance is not performed correctly, the keeper is liable forany eventual malfunction. To preserve characteristics,

performance, and safety, adequate servicing is necessary.Controls and periodic checks serve to establish whenmaintenance is needed and if a maintenance interventionhas been performed, to verify the restoration of safetyand standards performance.8

Usually, a certain amount of visual inspection, measure-ment, and functional tests must be performed to ensuresafety of the device. After such testing, measured datashould be recorded on a suitable board that also containsthe previous test results. Comparison of the latest resultswith past results enables determination of whether thedevice is still usable. According to IEC EN 62353,9 visualinspection should include attention to damage or contam-ination; integrity of mechanical parts; relevant accessories(eg, detachable or fixed power supply cords, patient leads,and tubing), which should be assessed along with themedical device; required documentation that reflects thecurrent revision of the device; safety-related markings andlabeling, which should be legible and complete; and allfuses, which should be compliant with the data provided bythe manufacturer (eg, rated current and characteristics). Inaddition, visual inspection should include attention to theconditions of any existing protective device; cleanliness ofany filters; condition of coupling and supply cables includ-ing any appliance coupler, plug, and socket-outlet; condi-

tion of the protective earth conductor; and functional status

of indicator lights and of audible and visual alarms.

If testing is performed before the equipment is put into

service, attention should be ensured that the equipment

delivered is that which was purchased, including markings;

that it is compatible with the available power, hydraulic, andpneumatic supplies; that installation is in accord with

accompanying documents; that a technician, qualified by

the manufacturer, is present during installation of complex

systems; that training of operators is completed, according

to the purchase order; that protection against electrical

hazards is verified according to IEC EN 60601-1;8 that

safety requirements according to the relevant standard are

verified; and that functional tests comply with the accom-

panying documents or relevant guidelines.

Measurements are established using the following tests:

protective earth resistance; insulation resistance; and device-

earth leakage current, applied part leakage current, patient

leakage current, and patient auxiliary current.

Measurements must be accomplished under normal con-

ditions and under single-fault conditions. As a result of

testing, equipment should be labeled as usable, tempo-

rarily usable with restrictions (waiting for upgrading orrepair), or not usable (waiting for upgrading, repair, orreplacement).

Frequency of testing, as stipulated by the manufacturer,should be every 6 to 36 months. However, for testing ofequipment and systems used in the operating room, theminimum period should not exceed 24 months.

DISCUSSION

Electrical safety is required during transplantation or anyother surgical procedure. When their natural protection isconsiderably decreased, patients are particularly vulnerableto electrical hazards. Even low current may be sufficient tocause respiratory paralysis or potentially fatal ventricularfibrillation (microshock). The reliability of the power supplysystem is closely related to patient health because of thedependence of diagnoses and therapies on the functioningof the electrical equipment. Voltage interruptions and poorquality of the power supply can affect life-supporting equip-

ment and cause deterioration of the performance of elec-

trical devices. The hospital administrator is responsible forpreservation of the characteristics and performance ofmedical devices. This must be accomplished via adequateservicing, maintenance checks, and so forth.

In addition to normative references, the following guide-lines have been proposed: adoption of a monitoring systemto improve the quality of electrical parameters in theoperating room; institution of emergency procedures formanagement of electrical faults; development of a proce-dure to manage fires in the operating room; and mainte-nance interventions and inspections of medical devices to

maintain minimal requirements of safety and performance.

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REFERENCES

1. Carrescia V: Fundamentals of electrical safety [in Italian].TNE Ed, 2009

2. IEC 60364-7-710 Ed 1.0 b:2002: Electrical installations ofbuildings: part 7710, Requirements for special installations or

locations:medical locations. 20023. Holme C: Healthcare interpretation of IEE guidance note 7

(chapter 10) and IEC 60364-7-710 for Electrical Installations inMedical Locations. The Engineering Team, Quarry House, 2005

4. Council Directive 93/42/EEC of 14 June 1993 concerningmedical devices (with amendments).

5. Directive 2007/47/EC of the European Parliament and of theCouncil of 5 September 2007 amending Council Directive 90/385/EEC, Council Directive 93/42/EEC, and Directive 98/8/EC.

6. Council Directive 90/385/EEC of 20 June 1990 on the approx-imation of the laws of the Member States relating to activeimplantable medical devices (with amendments).

7. Directive 98/79/EC of the European Parliament and of theCouncil of 27 October 1998 on in vitro diagnostic medicaldevices.

8. IEC EN 60601-1:2006: Medical Electrical Equipment: part 1;General requirements for basic safety and essential performance.

9. IEC EN 62353: 2008. Medical Electrical Equipment: recur-rent test and test after repair of medical electrical equipment.

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