#GHTF/SG1/N41R9：2005FINALDOCUMENTTitle：EssentialPrinciplesofSafetyandPerformanceofMedicalDevicesAuthoringGroup：GHTFStudyGroup1Endorsedby：TheGlobalHarmonizationTaskForceDate:May20,2005AbraaoCarvalho，GHTFChairThisdocumentwasproducedbytheGlobalHarmonizationTaskForce,avoluntaryinternationalgroupofrepresentativesfrommedicaldeviceregulatoryauthoritiesandtradeassociationsfromEurope,theUnitedStatesofAmerica(USA)，Canada，JapanandAustralia.Thedocumentisintendedtoprovidenon—bindingguidancetoregulatoryauthoritiesforuseintheregulationofmedicaldevices,andhasbeensubjecttoconsultationthroughoutitsdevelopment。Therearenorestrictionsonthereproduction，distributionoruseofthisdocument；however,incorporationofthisdocument，inpartorinwhole，intoanyotherdocument，oritstranslationintolanguagesotherthanEnglish,doesnotconveyorrepresentanendorsementofanykindbytheGlobalHarmonizationTaskForce.Copyright?2000bytheGlobalHarmonizationTaskForceTableofContents121。Introduction12TOC\o"1-5"\h\z\o"CurrentDocument"Rationale.PurposeandScope13\o"CurrentDocument"2。1Rationale13\o"CurrentDocument"Purpose13\o"CurrentDocument"2。3Scope14\o"CurrentDocument"3。References14

4.Definitions154.Definitions15165。EssentialPrinciplesofSafetyandPerformanceofMedicalDevices16PrefaceThedocumenthereinwasproducedbytheGlobalHarmonizationTaskForce,avoluntarygroupofrepresentativesfrommedicaldeviceregulatoryauthoritiesandtheregulatedindustry。Thedocumentisintendedtoprovidenon-bindingguidanceforuseintheregulationofmedicaldevices，andhasbeensubjecttoconsultationthroughoutitsdevelopment.Therearenorestrictionsonthereproduction，distribution，translationoruseofthisdocumenthowever，incorporationofthisdocument,inpartorinwhole，intoanyotherdocumentdoesnotconveyorrepresentanendorsementofanykindbytheGlobalHarmonizationTaskForce.IntroductionTheprimarywayinwhichtheGHTFachievesitsgoalsisthroughtheproductionofaseriesofguidancedocumentsthattogetherdescribeaglobalregulatorymodelformedicaldevices.Thepurposeofsuchguidanceistoharmonizethedocumentationandproceduresthatareusedtoassesswhetheramedicaldeviceconformstotheregulationsthatapplyineachjurisdiction.Eliminatingdifferencesbetweenjurisdictionsdecreasesthecostofgainingregulatorycomplianceandallowspatientsearlieraccesstonewtechnologiesandtreatments。Thisdocumenthasbeendevelopedtoencourageandsupportglobalconvergenceofregulatorysystems.ItisintendedforusebyRegulatoryAuthorities,ConformityAssessmentBodiesandindustry，andwillprovidebenefitsinestablishing，inaconsistentway，aneconomicandeffectiveapproachtothecontrolofmedicaldevicesintheinterestofpublichealth。ItseekstostrikeabalancebetweentheresponsibilitiesofRegulatoryAuthoritiestosafeguardthehealthoftheircitizensandtheirobligationstoavoidplacingunnecessaryburdensupontheindustry。StudyGroup1oftheGHTFsupportsandencouragesregulatoryharmonizationbutrecognisesthatsomeRegulatoryAuthoritiesmayhavetoreflectdifferentlocalneedswhentheyintroducenewregulationsonconformityassessment。However,RegulatoryAuthoritiesthataredevelopingconformityassessmentschemesoramendingexistingonesareencouragedtoconsidertheadoptionofthesystemdescribedinthisdocument，asthiswillhelptoreducethediversityofschemesworldwideandfacilitatetheprocessofharmonization.TheGHTFhasidentifiedasaprioritytheneedtoharmonizeessentialsafetyandperformancecriteriaforamedicaldevicethatallowthemanufacturertodemonstrateitsproductissuitableforitsintendeduse。ThisgoalwasachievedthroughthepublicationofguidanceonthesubjectentitledEssentialPrinciplesofSafetyandPerformanceofMedicalDevices(SG1/N020ofJune30,1999)thatappliedtothemajorityofmedicaldevicesbutnottoinvitrodiagnosticdevices.Thiscurrentdocumentsupersedesthatearlierone.Themajordifferencebetweenthemistheexpandedscope;thisdocumentnowincludesmedicaldevicesfortheinvitroexaminationofspecimensderivedfromthehumanbody.Theregulatoryrequirementsofsomecountriesdonot,atthistime,alignfullywiththisguidance.StudyGroup1oftheGlobalHarmonizationTaskForce(GHTF)haspreparedthisguidancedocument.CommentsorquestionsaboutitshouldbedirectedtoeithertheChairmanorSecretaryofGHTFStudyGroup1whosecontactdetailsmaybefoundontheGHTFwebpage1Rationale,PurposeandScopeRationaleConsistentidentification,selectionandapplicationofsafetyandperformanceprinciplestoamedicaldeviceofferssignificantbenefitstothemanufacturer，user，patientorconsumer，andtoRegulatoryAuthoritiessinceitallowsitsmanufacturertodesign,manufactureanddemonstratethedeviceissuitableforitsintendeduse。Moreover,eliminatingdifferencesbetweenjurisdictionsdecreasesthecostofgainingregulatorycomplianceandallowspatientsearlieraccesstonewtechnologiesandtreatments.PurposeTodescribesixgeneralrequirementsofsafetyandperformancethatapplytoallmedicaldevices.Toprovideacomprehensivelistofdesignandmanufacturingrequirementsofsafetyandperformance,someofwhicharerelevanttoeachmedicaldevice.Thesearegroupedas：Chemical,physicalandbiologicalproperties.Infectionandmicrobialcontamination.Manufacturingandenvironmentalproperties.Deviceswithadiagnosticormeasuringfunction。Protectionagainstradiation.Requirementsformedicaldevicesconnectedtoorequippedwithanenergysource.Protectionagainstmechanicalrisks。Protectionagainsttherisksposedtothepatientbysuppliedenergyorsubstances.Protectionagainsttherisksposedtothepatientfordevicesforself—testingorselfadministration.Informationsuppliedbythemanufacturer.Performanceevaluationincluding,whereappropriate,clinicalevaluation。Note：themanufacturerselectswhichofthedesignandmanufacturingrequirementsarerelevanttoaparticularmedicaldevice,documentingthereasonsforexcludingtheothers.TheRegulatoryAuthorityand/orConformityAssessmentBodymayverifythisdecisionduringtheconformityassessmentprocess.ScopeThisdocumentappliestoallproductsthatfallwithinthedefinitionofamedicaldevicethatappearswithintheGHTFdocumentInformationDocumentConcerningtheDefinitionoftheTerm“MedicalDevice”,includingthoseusedfortheinvitroexaminationofspecimensderivedfromthehumanbody。ReferencesGHTFfinaldocumentsSG1/N009LabellingforMedicalDevicesSG1/N012RoleofStandardsintheAssessmentofMedicalDevices.SG1/N020EssentialPrinciplesofSafetyandPerformanceofMedicalDevicesGHTFdocumentsavailableforpubliccommentSG1（PD）/N011SummaryTechnicalDocumentationforDemonstratingConformitytotheEssentialPrinciplesofSafetyandPerformanceofMedicalDevices.SG1（PD）/N029InformationDocumentConcerningtheDefinitionoftheTerm‘MedicalDevice'.SG1（PD）/N043LabellingforMedicalDevices（revised）.GHTFdocumentbeingpreparedforpubliccommentSG1(PD)/N040PrinciplesofConformityAssessmentforMedicalDevices。InternationalstandardISO14971：2001Medicaldevices—Applicationofriskmanagementtomedicaldevices.ISO/TR16142：2004MedicalDevices—GuidanceontheSelectionofStandardsinSupportoftheRecognizedEssentialPrinciplesofSafetyandPerformanceofMedicalDefinitionsClinicalevaluation：Thereviewofrelevantscientificliteratureand/orthereviewandassessmentofdatacollectedthroughclinicalinvestigation。Clinicalinvestigation：Anydesignedandplannedsystematicstudyinhumansubjectsundertakentoverifythesafetyand/orperformanceofaspecificdevice。(Source—ISO/DIS14155—1)Deviceforself—testing/self—administration:Anydeviceintendedbythemanufacturertobeabletobeusedbylaypersonsinanon-clinicalenvironment。(Source—basedonEuropeanDirective98/79/EC)Harm:Physicalinjuryordamagetothehealthofpeopleordamagetopropertyortheenvironment.(Source—ISO/IECGuide51：1999)Hazard:Potentialsourceofharm.(Source—ISO/IECGuide51:1999)Intendeduse/purpose：Theobjectiveintentofthemanufacturerregardingtheuseofaproduct，processorserviceasreflectedinthespecifications，instructionsandinformationprovidedbythemanufacturer.(Source—21CFR801.4)Medicaldevice：RefertoGHTFguidancedocument：InformationConcerningtheDefinitionoftheTerm“MedicalDevice"(SG1/N029).Performanceevaluation：Reviewoftheperformanceofamedicaldevicebasedupondataalreadyavailable，scientificliteratureand,whereappropriate，laboratory，animalorclinicalinvestigations。RegulatoryAuthority(RA):Agovernmentagencyorotherentitythatexercisesalegalrighttocontroltheuseorsaleofmedicaldeviceswithinitsjurisdiction，andmaytakeenforcementactiontoensurethatmedicalproductsmarketedwithinitsjurisdictioncomplywithlegalrequirements。(Source—EU—CanadaMRA)Risk:Combinationoftheprobabilityofoccurrenceofharmandtheseverityofthatharm.(Source—ISO/IECGuide51:1999)Specimen：Thediscreteportionofabodyfluidortissueorothersampleassociatedwiththebodytakenforexamination，study,oranalysisofoneormorequantityorcharacteristictodeterminethecharacterofthewhole.EssentialPrinciplesofSafetyandPerformanceofMedicalDevicesGeneralRequirementsMedicaldevicesshouldbedesignedandmanufacturedinsuchawaythat，whenusedundertheconditionsandforthepurposesintendedand,whereapplicable,byvirtueofthetechnicalknowledge，experience，educationortrainingofintendedusers,theywillnotcompromisetheclinicalconditionorthesafetyofpatients，orthesafetyandhealthofusersor，whereapplicable,otherpersons,providedthatanyriskswhichmaybeassociatedwiththeiruseconstituteacceptableriskswhenweighedagainstthebenefitstothepatientandarecompatiblewithahighlevelofprotectionofhealthandsafety。Thesolutionsadoptedbythemanufacturerforthedesignandmanufactureofthedevicesshouldconformtosafetyprinciples，takingaccountofthegenerallyacknowledgedstateoftheart.Whenriskreductionisrequired，themanufacturershouldcontroltherisk(s)sothattheresidualrisk(s)associatedwitheachhazardisjudgedacceptable.Themanufacturershouldapplythefollowingprinciplesinthepriorityorderlisted:identifyknownorforeseeablehazardsandestimatetheassociatedrisksarisingfromtheintendeduseandforeseeablemisuse，eliminaterisksasfarasreasonablypracticablethroughinherentlysafedesignandmanufacture，reduceasfarasisreasonablypracticabletheremainingrisksbytakingadequateprotectionmeasures，includingalarms，informusersofanyresidualrisks.Devicesshouldachievetheperformanceintendedbythemanufacturerandbedesigned,manufacturedandpackagedinsuchawaythattheyaresuitableforoneormoreofthefunctionswithinthescopeofthedefinitionofamedicaldeviceapplicableineachjurisdiction.ThecharacteristicsandperformancesreferredtoinClauses5.1，5.2and5.3shouldnotbeadverselyaffectedtosuchadegreethatthehealthorsafetyofthepatientortheuserand，whereapplicable，ofotherpersonsarecompromisedduringthelifetimeofthedevice，asindicatedbythemanufacturer,whenthedeviceissubjectedtothestresseswhichcanoccurduringnormalconditionsofuseandhasbeenproperlymaintainedinaccordancewiththemanufacturer'sinstructions。Thedevicesshouldbedesigned,manufacturedandpackedinsuchawaythattheircharacteristicsandperformancesduringtheirintendedusewillnotbeadverselyaffectedundertransportandstorageconditions(forexample,fluctuationsoftemperatureandhumidity)takingaccountoftheinstructionsandinformationprovidedbythemanufacturer。Thebenefitsmustbedeterminedtooutweighanyundesirablesideeffectsfortheperformancesintended。DesignandManufacturingRequirementsChemical,physicalandbiologicalpropertiesThedevicesshouldbedesignedandmanufacturedinsuchawayastoensurethecharacteristicsandperformancereferredtoinClauses5.1to5.6ofthe'GenerRaelquirements'。Particularattentionshouldbepaidto:?thechoiceofmaterialsused,particularlyasregardstoxicityand，whereappropriate，flammability，?thecompatibilitybetweenthematerialsusedandbiologicaltissues，cells，bodyfluids,andspecimens，takingaccountoftheintendedpurposeofthedevice。?thechoiceofmaterialsusedshouldreflect,whereappropriate,matterssuchashardness,wearandfatiguestrength。Thedevicesshouldbedesigned,manufacturedandpackedinsuchawayastominimizetheriskposedbycontaminantsandresiduestothepersonsinvolvedinthetransport,storageanduseofthedevicesandtopatients，takingaccountoftheintendedpurposeoftheproduct.Particularattentionshouldbepaidtotissuesexposedandtothedurationandfrequencyofexposure。Thedevicesshouldbedesignedandmanufacturedinsuchawaythattheycanbeusedsafelywiththematerials,substancesandgaseswithwhichtheyenterintocontactduringtheirnormaluseorduringroutineprocedures;ifthedevicesareintendedtoadministermedicinalproductstheyshouldbedesignedandmanufacturedinsuchawayastobecompatiblewiththemedicinalproductsconcernedaccordingtotheprovisionsandrestrictionsgoverningtheseproductsandthattheirperformanceismaintainedinaccordancewiththeintendeduse。Whereadeviceincorporates，asanintegralpart,asubstancewhich,ifusedseparately,maybeconsideredtobeamedicinalproduct/drugasdefinedintherelevantlegislationthatapplieswithinthatjurisdictionandwhichisliabletoactuponthebodywithactionancillarytothatofthedevice，thesafety,qualityandusefulnessofthesubstanceshouldbeverified，takingaccountoftheintendedpurposeofthedevice.Thedevicesshouldbedesignedandmanufacturedinsuchawayastoreduceasfarasreasonablypracticableandappropriatetherisksposedbysubstancesthatmayleachorleakfromthedevice。Devicesshouldbedesignedandmanufacturedinsuchawayastoreduceasfarasreasonablypracticableandappropriaterisksposedbytheunintentionalingressoregressofsubstancesintoorfromthedevicetakingintoaccountthedeviceandthenatureoftheenvironmentinwhichitisintendedtobeused.InfectionandmicrobialcontaminationThedevicesandmanufacturingprocessesshouldbedesignedinsuchawayastoeliminateortoreduceasfarasreasonablypracticableandappropriatetheriskofinfectiontopatients，usersand,whereapplicable,otherpersons.Thedesignshould:?alloweasyhandling,and，wherenecessary：?reduceasfarasreasonablypracticableandappropriateanymicrobialleakagefromthedeviceand/ormicrobialexposureduringuse，?preventmicrobialcontaminationofthedevice，orspecimenwhereapplicable,bythepatient,userorotherperson.Whereadeviceincorporatessubstancesofbiologicalorigin,theriskofinfectionmustbereducedasfarasreasonablypracticableandappropriatebyselectingappropriatesources,donorsandsubstancesandbyusing，asappropriate，validatedinactivation,conservation,testandcontrolprocedures.Insomejurisdictionsproductsincorporatingtissues,cellsandsubstancesofnonhumanoriginmaybeconsideredmedicaldevices.Inthiscase，suchtissues，cellsandsubstancesshouldoriginatefromanimalsthathavebeensubjectedtoveterinarycontrolsandsurveillanceadaptedtotheintendeduseofthetissues。Nationalregulationsmayrequirethatthemanufacturerand/ortheRegulatoryAuthorityretaininformationonthegeographicaloriginoftheanimals。Processing,preservation,testingandhandlingoftissues，cellsandsubstancesofanimaloriginshouldbecarriedoutsoastoprovideoptimalsafety.Inparticular，safetywithregardtovirusesandothertransmissibleagentsshouldbeaddressedbyimplementationofvalidatedmethodsofp???????T?eliminationorinactivationinthecourseofthemanufacturingprocess。Insomejurisdictionsproductsincorporatinghumantissues,cellsandsubstancesmaybeconsideredmedicaldevices.Inthiscase，theselectionofsources,donorsand/orsubstancesofhumanorigin,theprocessing，preservation,testingandhandlingoftissues，cellsandsubstancesofsuchoriginshouldbecarriedoutsoastoprovideoptimalsafety.Inparticular,safetywithregardtovirusesandothertransmissibleagentsshouldbeaddressedbyimplementationofvalidatedmethodsofeliminationorinactivationinthecourseofthemanufacturingprocess。Deviceslabelledashavingaspecialmicrobiologicalstateshouldbedesigned，manufacturedandpackedtoensuretheyremainsowhenplacedonthemarketandremainsounderthetransportandstorageconditionsspecifiedbythemanufacturer.Devicesdeliveredinasterilestateshouldbedesigned,manufacturedandpackedinanon-reusablepack，and/oraccordingtoappropriateprocedures,toensurethattheyaresterilewhenplacedonthemarketandremainsterile，underthetransportandstorageconditionsindicatedbythemanufacturer,untiltheprotectivepackagingisdamagedoropened。Deviceslabelledeitherassterileorashavingaspecialmicrobiologicalstateshouldhavebeenprocessed,manufacturedand，ifapplicable,sterilizedbyappropriate,validatedmethods.Devicesintendedtobesterilizedshouldbemanufacturedinappropriatelycontrolled（e.g。environmental）conditions.Packagingsystemsfornon—steriledevicesshouldkeeptheproductwithoutdeteriorationatthelevelofcleanlinessstipulatedand，ifthedevicesaretobesterilizedpriortouse，minimizetheriskofmicrobialcontamination;thepackagingsystemshouldbesuitabletakingaccountofthemethodofsterilizationindicatedbythemanufacturer.Thepackagingand/orlabelofthedeviceshoulddistinguishbetweenidenticalorsimilarproductsplacedonthemarketinbothsterileandnon—sterilecondition。5.9ManufacturingandenvironmentalpropertiesIfthedeviceisintendedforuseincombinationwithotherdevicesorequipment，thewholecombination，includingtheconnectionsystemshouldbesafeandshouldnotimpairthespecifiedperformanceofthedevices。Anyrestrictionsonuseapplyingtosuchcombinationsshouldbeindicatedonthelabeland/orintheinstructionsforuse。Devicesshouldbedesignedandmanufacturedinsuchawayastoremoveorreduceasfarasreasonablypracticableandappropriate:?theriskofinjury，inconnectionwiththeirphysicalfeatures，includingthevolume/pressureratio,dimensionalandwhereappropriateergonomicfeatures;?risksconnectedwithreasonablyforeseeableexternalinfluencesorenvironmentalconditions，suchasmagneticfields，externalelectricalandelectromagneticeffects，electrostaticdischarge，pressure，humidity，temperatureorvariationsinpressureandacceleration;?herisksconnectedtotheiruseinconjunctionwithmaterials，substancesandgaseswithwhichtheymaycomeintocontactduringnormalconditionsofuse;?therisksofaccidentalpenetrationofsubstancesintothedevice；?theriskofincorrectidentificationofspecimens；?therisksofreciprocalinterferencewithotherdevicesnormallyusedintheinvestigationsorforthetreatmentgiven；?risksarisingwheremaintenanceorcalibrationarenotpossible(aswithimplants),fromageingofmaterialsusedorlossofaccuracyofanymeasuringorcontrolmechanism.Devicesshouldbedesignedandmanufacturedinsuchawayastominimizetherisksoffireorexplosionduringnormaluseandinsinglefaultcondition。Particularattentionshouldbepaidtodeviceswhoseintendeduseincludesexposuretooruseinassociationwithflammablesubstancesorsubstanceswhichcouldcausecombustion.Devicesmustbedesignedandmanufacturedinsuchawayastofacilitatethesafedisposalofanywastesubstances。DeviceswithadiagnosticormeasuringfunctionDeviceswithameasuringfunction，whereinaccuracycouldhaveasignificantadverseeffectonthepatient,shouldbedesignedandmanufacturedinsuchawayastoprovidesufficientaccuracy,precisionandstabilityfortheirintendedpurposeofthedevice。Thelimitsofaccuracyshouldbeindicatedbythemanufacturer。Diagnosticdevicesshouldbedesignedandmanufacturedinsuchawayastoprovidesufficientaccuracy,precisionandstabilityfortheirintendeduse,basedonappropriatescientificandtechnicalmethods。Inparticularthedesignshouldaddresssensitivity，specificity,trueness,repeatability,reproducibility，controlofknownrelevantinterferenceandlimitsofdetection,asappropriate。Wheretheperformanceofdevicesdependsontheuseofcalibratorsand/orcontrolmaterials，thetraceabilityofvaluesassignedtosuchcalibratorsand/orcontrolmaterialsshouldbeassuredthroughaqualitymanagementsystem。Anymeasurement,monitoringordisplayscaleshouldbedesignedinlinewithergonomicprinciples，takingaccountoftheintendedpurposeofthedevice.Whereverpossiblevaluesexpressednumericallyshouldbeincommonlyaccepted,standardisedunits,andunderstoodbytheusersofthedevice.Note：WhileSG1generallysupportsconvergenceontheglobaluseofinternationallystandardisedmeasurementunits，considerationsofsafety，userfamiliarity，andestablishedclinicalpracticemayjustifytheuseofotherrecognisedmeasurementunits。ProtectionagainstradiationGeneralDevicesshouldbedesignedandmanufacturedandpackagedinsuchawaythatexposureofpatients,usersandotherpersonstoanyemittedradiationshouldbereducedasfaraspracticableandappropriate,compatiblewiththeintendedpurpose，whilstnotrestrictingtheapplicationofappropriatespecifiedlevelsfortherapeuticanddiagnosticpurposes。5.11.2IntendedradiationWheredevicesaredesignedtoemithazardous,orpotentiallyhazardous,levelsofvisibleand/orinvisibleradiationnecessaryforaspecificmedicalpurposethebenefitofwhichisconsideredtooutweightherisksinherentintheemission,itshouldbepossiblefortheusertocontroltheemissions.Suchdevicesshouldbedesignedandmanufacturedtoensurereproducibilityofrelevantvariableparameterswithinanacceptabletolerance.Wheredevicesareintendedtoemitpotentiallyhazardous,visibleand/orinvisibleradiation,theyshouldbefitted,wherepracticable,withvisualdisplaysand/oraudiblewarningsofsuchemissions。UnintendedradiationDevicesshouldbedesignedandmanufacturedinsuchawaythatexposureofpatients,usersandotherpersonstotheemissionofunintended,strayorscatteredradiationisreducedasfaraspracticableandappropriate。InstructionsforuseTheoperatinginstructionsfordevicesemittingradiationshouldgivedetailedinformationastothenatureoftheemittedradiation,meansofprotectingthepatientandtheuserandonwaysofavoidingmisuseandofeliminatingtherisksinherentininstallation.IonizingradiationDevicesintendedtoemitionizingradiationshouldbedesignedandmanufacturedinsuchawayastoensurethat,wherepracticable,thequantity，geometryandenergydistribution(orquality)ofradiationemittedcanbevariedandcontrolledtakingintoaccounttheintendeduse。Devicesemittingionizingradiationintendedfordiagnosticradiologyshouldbedesignedandmanufacturedinsuchawayastoachieveappropriateimageand/oroutputqualityfortheintendedmedicalpurposewhilstminimisingradiationexposureofthepatientanduser。Devicesemittingionizingradiation,intendedfortherapeuticradiologyshouldbedesignedandmanufacturedinsuchawayastoenablereliablemonitoringandcontrolofthedelivereddose,thebeamtypeandenergyandwhereappropriatetheenergydistributionoftheradiationbeam.RequirementsformedicaldevicesconnectedtoorequippedwithanenergysourceDevicesincorporatingelectronicprogrammablesystems,includingsoftware，shouldbedesignedtoensuretherepeatability，reliabilityandperformanceofthesesystemsaccordingtotheintendeduse.Intheeventofasinglefaultconditioninthesystem,appropriatemeansshouldbeadoptedtoeliminateorreduceasfaraspracticableandappropriateconsequentrisks.Deviceswherethesafetyofthepatientsdependsonaninternalpowersupplyshouldbeequippedwithameansofdeterminingthestateofthepowersupply.Deviceswherethesafetyofthepatientsdependsonanexternalpowersupplyshouldincludeanalarmsystemtosignalanypowerfailure。Devicesintendedtomonitoroneormoreclinicalparametersofapatientshouldbeequippedwithappropriatealarmsystemstoalerttheuserofsituationswhichcouldleadtodeathorseveredeteriorationofthepatient'sstateofhealthDevicesshouldbedesignedandmanufacturedinsuchawayastoreduceasfaraspracticableandappropriatetherisksofcreatingelectromagneticinterferencewhichcouldimpairtheoperationofthisorotherdevicesorequipmentintheusualenvironment。Devicesshouldbedesignedandmanufacturedinsuchawayastoprovideanadequatelevelofintrinsicimmunitytoelectromagneticdisturbancetoenablethemtooperateasintended.ProtectionagainstelectricalrisksDevicesshouldbedesignedandmanufacturedinsuchawayastoavoid,asfaraspossible，theriskofaccidentalelectricshocksduringnormaluseandinsinglefaultcondition，providedthedevicesareinstalledandmaintainedasindicatedbythemanufacturer。ProtectionagainstmechanicalrisksDevicesshouldbedesignedandmanufacturedinsuchawayastoprotectthepatientanduseragainstmechanicalrisksconnectedwith,forexample,resistancetomovement,instabilityandmovingparts.Devicesshouldbedesignedandmanufacturedinsuchawayastoreducetothelowestpracticableleveltherisksarisingfromvibrationgeneratedbythedevices，takingaccountoftechnicalprogressandofthemeansavailableforlimitingvibrations，particularlyatsource，unlessthevibrationsarepartofthespecifiedperformance.Devicesshouldbedesignedandmanufacturedinsuchawayastoreducetothelowestpracticableleveltherisksarisingfromthenoiseemitted,takingaccountoftechnicalprogressandofthemeansavailabletoreducenoise,particularlyatsource,unlessthenoiseemittedispartofthespecifiedperformance。Terminalsandconnectorstotheelectricity,gasorhydraulicandpneumaticenergysupplieswhichtheuserhastohandleshouldbedesignedandconstructedinsuchawayastominimizeallpossiblerisks.Accessiblepartsofthedevices(excludingthepartsorareasintendedtosupplyheatorreachgiventemperatures)andtheirsurroundingsshouldnotattainpotentiallydangeroustemperaturesundernormaluse。Protectionagainsttherisksposedtothepatien