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Guidelines– monitoring,evacuationandequipment

DanielRoberts(seniorradiographer)KristopherKnott(CMRfellow) EffectiveMonitoring

Whydoweneedmonitoring?

• CMRisreliantonECGgating

• DirectmonitoringofpatientECGisanadditionalnecessitywhenscanningdevicepatients

• Ofprimaryconcernisanydeviationfromexpectedheartrhythm/rate• Dependentonchosenpre-scandevicesettings• Tobediscussedwithallrelevantteammemberspre-scan(cardiologist/s,cardiacphysiologist/sandradiographer/s)

• Furtherteamdiscussion:Typeofdevice(PPM/ICD,conditional/non-conditional),leads,underlyingrhythm,expectedresponsetostress…etc

BHCSOP:ScanningofPatientswithPPM• TwoformsofmonitoringviaECGandpulseoximetry

• Typical4leadECGusedforclinicalCMRissufficientforpurpose• Tobesetupassoonafterre-programmingofdeviceaspossible• CanbedoneoutsidescanroomitselfwherewirelessECGprobesareutilised

• Pulseoximetryusedasasurrogateforrhythmanalysisinsituationswhenelectrocardiographyexhibitsartefact

• RealtimemonitoringofO2saturationlevels

FactorseffectingECGtrace

• Vectorcardiographic (VCG)techniquesarethemostcommonclinicalnormforECGmonitoring/gating:• Overcomesthemagnetohydrodynamiceffect• Higherfieldstrength=greatereffect

• RFandGradients• LowSARmodeormanualreductionofgradientsifabsolutelynecessary

• Movementofpatientwithinstaticfield:• CloselymonitorECGwhenmovingthepatientintothescanner• Watchforrhythmpausingandadjustdevicesettingsifnecessary

ObtainingastrongECGtrace

• Adequateskinpreparation:• Removalofnaturallyoccurringoilsandbodyhair• Mildlyabrasivepreparationgel

• ECGelectrodepositioning:• CreativeelectrodeplacementmaybenecessaryforastrongECGtracedependingonbodyhabitusanddeviceposition

• Trialanderrorapproachmayneedtobeadoptedregardingelectrodepositioningandchannelselection

• Excessivepatientmovementmayalsoillicitartefact

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ObtainingastrongPulseOximetrytrace• MostclinicalCMRscannerswillallowforpulseoximetry,however:

• ForECGgatingonly• Dedicatedpulseoximetryrequiredtomeasureoxygenation• Audiblealarmwhenoxygensaturationdropsbelowgiventhreshold

• Signaldropoutmayrequirestrialanderrorwithalternativefingersorprobetype:• Peripheralvasoconstriction(coldextremities)• Poorcardiacoutput• Excessivemovement;tremors• Nailpolish(darklypigmented)

EvacuationProcedures

BHCEvacuationProcedure

1. OnlyauthorisedCMRstaffaretoenterthescanroomintheeventofanemergency

2. CMRstaffmustremovepatientfromwithintheboreandtransferpatientontoaCMRcompatibletrolley(tobekeptinthescanroom)

3. 2222iscalledbyamemberofstaff4. Patientisremovedfromscanroomandtakentorecoverybay

wherecrashteamwilladministeremergencymeasures

1.CMRauthorisedstaffonlyinthescanroom• Authorisedmeans:

• CertifiedtoenteranMRcontrolledarea• AmemberofMRcentrepersonnel• MusthavereadandunderstoodlocalrulesregardingMRsafety• Completedasafetyscreeningquestionnaireannually

• Keepalltraininguptodateandwelldocumented

• Asalways,itistheresponsibilityofauthorised/responsiblestaffmemberstoensurenounauthorisedpersonsenterthescanroom

2.PatientremovedfromscannertoCMRcompatibletrolley• MRcompatibletrolleytobepresentatalltimesandwithoutfail• Keeptrolleyclearofclutter• Trolleybreakstobekeptunlockedinordertofacilitateswiftevacuation• Evacuationsheetisofparticularimportance

• For‘highrisk’patients– earlyECGmonitoringandexternalpacingequipmentinpreparationroom

• Allinvolvedstafftobefullytrainedinsafemanualhandlingtechniques• Evacuationroutesshouldbeclearofobstructions/triphazards

3.Callingforappropriatesupport

• StandardBLSprocedureincaseofcardiacarrest• Crashcall:2222orequivalent• Informsupervisingconsultant/s

• Staffwhoshouldalreadybepresent:• Radiographer(ALSqualified)• Cardiologist(ALSqualified)ifnon-conditionaldevice• Cardiacphysiologist• +/- MRPhysicistifgreatdealofartefactencountered

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Evacuationsupportinpractice

• Ensurethatrequiredlevelsoflifesupporttrainingaremaintained:• Mandatorytraininguptodate• Supplementarytrainingifrequired• Documentation

• Thescanningofdevicesrequirestheattentionofallinvolvedmembersofstaff• Minimumstaffinglevelsmaintainedatalltimesincaseofemergency• Allinvolvedstaffmemberstobeinimmediatevicinityoreasilyandreliablycontactable

• 1deviceCMRperteam

4.Evacuationfromscanroom

• Incaseofemergency,patienttobemovedtoZone3asquicklyaspossible• Zone4– Synonymouswithscanroomitself• Zone3– Outsidescanroomdoor.Accessforsafetyscreenedpatientsandstaffonly.Oftencontrolroom/anteroom.

• Zone2– Nodetectiblemagneticfieldbutrestrictedtostaff,patientandfamilies

• Zone1– Norestriction

• Therefore,ensureallthoseresponsibleforfirstresponseinanemergencyhavebeensafetyscreened

Recoveryareaindetail

• Zone3• Dedicated/aptforpurpose:

• Appropriatesize• Unoccupied• Clearofobstruction• Allowsforprivacy

• Withineasyreachofcrashtrolley:• AEDwithexternalpacingcapacity• Atropineandadrenaline

• Deviceprogrammerforrelevantmanufacturers• Devicemagnet

Pre-scan– knowyourpatient

• Whatdevicedoesyourpatienthave?

• Terminology:• PPM,CRT-P,CRT-D,ICD,S-ICD

• Arealldevicesthesame?

• Whywasthedeviceputin?

Pre-scan– knowyourpatient

• Whatisthedevicedoinginthispatient?

• Whatdomagnetsdotothedevice?

• Whatcangowronginthescanner?

• IsthedeviceMRconditional?

• Howhasthedevicebeenprogrammedpre-scan?

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Terminology

• PPM– permanentpacemaker• ICD– implantablecardioverterdefibrillator• CRT-P- Cardiacresynchronisationtherapy– pacemaker• CRT-D- Cardiacresynchronisationtherapy– defibrillator• S-ICD– subcutaneousICD

Pre-scan– settinguptheequipment

• MRIsafetrolley• Patslide/sheet• Resuscitationtrolley• Defibrillator

Pre-scan– whoishighrisk?

• Pacingdependent

• Highthresholdsinleadspre-scan

• Oldorbrokenleads

• Historyofrecentventriculararrhythmia

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Pre-scan– whoneedstobethere?

• Radiographer

• Physiologist– deviceprogramming,monitoringinhighrisk

• Cardiologist– non-conditional,highriskpatients

Pacemakers

• Isthepatient“pacingdependent”?• Whathappensifyouturnoffthepacemaker?!

• Thepacemakeriseithera“back-up”,incasetheheart’sconductionsystemfails….

…..Orthethepacemakerispacingmost/allofthetime.

Scenario1

Keypoint:knowwhatratethepacemakerwasprogrammedtopre-scan

Scenario1– bradycardiaduringthescan

• Ifpacinginhibitionisobservedduringthescan1. Abortthescan2. Movethepatienttozone33. Checkifpacinghasresumed4. Applyamagnettothepacemaker&/orprogramtoasynchronous

pacing5. Applyexternaldefibrillationpadsfortranscutaneouspacing6. ALS

Whatdoesamagnetdotoapacemaker?

• Typicallyasynchronouspacing• Paceatmagnetrate(forexample100bpm,90bpmor85bpm– dependentonmanufacturer,model,batterylifeetc)

• DOO,VOO,AOO

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Scenario2

Scenario2– ventriculararrhythmias

• Ifsustainedventriculararrhythmiaorhaemodynamiccompromise1. Abortthescan2. Movethepatienttozone33. Re-activatetheICD4. Applyexternaldefibrillationpads5. ALS

Whatdoesamagnetdotoadefibrillator?

• Typicallyinhibitsarrhythmiadetection/therapydelivery• Noasynchronouspacing• Willnotre-activatethedefibrillatorinsomeonehavingVT• Willnotresumepacinginsomeoneasystolic

Resuscitation

• ABC• (CPR)• Applytheexternaldefibrillatorpads• Physiologistinterrogatesthedeviceconcurrently

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Lessobviouscases Pragmaticapproach– whentocutshortthescan?• Infrequent,fewbeatsofVT

• Thisisahighriskpatient– havethingssetupaccordingly(physiologist/cardiologistpresent)

• Scanquicklyanddothepoint• Abortifmoresustainedrunsoccur

• Patientsmaydevelopsymptomsduetoincreasedoutput/diaphragmaticpacing.• Thisisoftenwelltoleratedbutmaynotbe.

Summary

1. Knowyourpatient2. Knowyourpatient’sdevice3. Ensuretheresuscitationequipmentissetupcorrectlyandyou

knowwhereitis4. Haveanevacuationprocedureinplace5. Knowhowtotreatbrady andtachyarrhythmias inpatientswith

devices

Thanksforyourattention

• Anyquestions?