INTRODUCTION

TheregulationspromulgatedtoimplementtheamendedAnimalWelfareActrequirethatallsurvivalsurgerybeperformedusingasepticprocedures.Thisincludestheuseofsurgicalgloves,masks,sterileinstrumentsandaseptictechnique.

Inthischapter,thePrinciplesofAsepticTechniquewillbediscussedwiththeemphasisonthepracticalapplicationoftheseprinciplesinthelaboratorysetting.Incentralizedexperimentalsurgeries,awell-trainedstaffshouldbeavailabletoadvisethosewhousesuchfacilitiesandoverseeitsoperationtoensurethemaintenanceofanasepticenvironmentforsurvivalsurgery.Whensurvivalsurgeryisconductedoutsidesuchanenvironment,itistheprincipalinvestigator"sresponsibilitytoensurethatappropriateasepticconditionsandpracticesaremaintained.Thischapterwillprovidethenecessaryinformationtocarryoutthisresponsibility.

Priortodiscussingthespecificprinciplesofasepticsurgeryabriefreviewofpertinentterminologyisnecessary.

TERMINOLOGY

Antimicrobial-Anagentoractionthatkillsorinhibitsthegrowthofmicro-organisms.

Antiseptic-Achemicalagentthatisappliedtopicallytoinhibitthegrowthofmicro-organisms.

Asepsis-Preventionofmicrobialcontaminationoflivingtissuesorsterilematerialsbyexcluding,removingorkillingmicro-organisms.

Autoclave-Asteamsterilizerconsistingofametalchamberconstructedtowithstandthepressurethatisrequiredtoraisethetemperatureofsteamtothelevelrequiredforsterilization.Earlymodelsweretermed"autoclaves"becausetheywerefittedwithaself-closingdoor.

Bactericide-Achemicalorphysicalagentthatkillsvegetative(non-sporeforming)bacteria.

Bacteriostat-Anagentthatpreventsmultiplicationofbacteria.

Commensals-Non-pathogenicmicro-organismsthatarelivingandreproducingashumanoranimalparasites.

Contamination-Introductionofmicro-organismstosterilearticles,materialsortissues.

Disinfectant-Anagentthatisintendedtokillorremovepathogenicmicro-organisms,withtheexceptionofbacterialspores.

Pasteurization-Aprocessthatkillsnonspore-formingmicro-organismsbyhotwaterorsteamat65-100oC.

Pathogenic-Aspeciesthatiscapableofcausingdiseasemicro-organisminasusceptIBLehost.

Sanitization-Aprocessthatreducesmicrobialcontaminationtoalowlevelbytheuseofcleaningsolutions,hotwaterorchemicaldisinfectants.

Sterilant-Anagentthatkillsalltypesofmicro-organisms.

Sterile-Freefrommicro-organisms.

Sterilization-Thecompletedestructionofmicro-organisms.

SincethepioneeringworkofsuchsurgeonsasJosephLister,whointroducedtheuseofcarbolicacidantisepticsin1865,andWilliamHalstead,whoadvocatedtheuseofsurgicalglovesin1898,surgeonshavestrivedtoeliminatesurgicalinfectionsthroughtheuseofaseptictechnique.Potentialsourcesofcontaminationarewelldefined.Theyincludethepatientandthesurgicalenvironment:thesurgeonandsupportstaff,theinstruments,sutures,drapesandallotherequipmentwhichcanhavecontactwiththesurgicalfield.

FACILITIES

ThebasisforthisdiscussionaboutfacilitieswillbetherecommendationsforAsepticSurgerycontainedintheGuidefortheCareandUseofLaboratoryAnimals.TheGuidestates:

"Functionalareasforasepticsurgeryshouldincludeaseparatesupportarea,apreparationarea,theoperatingroomorroomsandanareaforintensivecareandsupportivetreatmentofanimals.Theinteriorsurfacesofthisfacilityshouldbeconstructedofmaterialsthatareimpervioustomoistureandeasilycleaned.Thesurgicalsupportareashouldbedesignedforstoringinstrumentsandsuppliesforwashingandsterilizinginstruments.Itemsthatareusedonaregularbasis,suchasanestheticmachinesandsuturematerials,canbestoredintheoperatingroom."

"Thereshouldbeaseparatesurgicalpreparationareaforanimals.Anareaequippedwithsurgicalsinksshouldbecloseto,butapartfrom,theoperatingroom.Adressingareashouldbeprovidedforpersonneltochangeintosurgicalattire."

Thesurgicalfacilityshouldbelocatedoutsidenormalfacilitytrafficpatterns.Thiscanhelptominimizethepotentialforsurgicalsuitecontaminationbythemovementofpersonnelandequipment.Personnelaccesstotheseareasshouldberestrictedtoessentialsurgicalsupportstaff.

Ideally,theoperatingroomventilationsystemshouldprovideanetpositivepressurewithrespecttothesurroundingfacilities.Thesystemshouldberegularlymonitored.Maintenanceworkshouldbeperformedwhenthesurgeryisidle.Ventilationfiltersshouldbeinspectedandcleanedorreplacedatregularintervals.Ifexplosiveanestheticsagentsaretobeused,theGuiderecommendsthatfloorsshouldbeconductiveandelectricaloutletsshouldbeexplosion-proofandlocatednotlessthan5feetoffthefloor.Dedicatedsurgicalfacilitiesshouldbeusedforasepticsurgeriesandthestorageofessentialsurgicalequipment,notasgeneralstoragespace.

EQUIPMENT

Theequipmentinareasusedforasepticsurgeryshouldbeeasytocleanandportabletosimplifysanitizationofthearea.TheoperatingtableshouldbeconstructedwithadurablesurfacematerialimpervioustomoisturewhichcanbereADIlycleaned.Plasticorstainlesssteelisfrequentlyusedforthispurpose.Otherusefultabledesignfeatureswhichassistpatientpositioningincludeheightandtiltadjustments,V-troughconfigurationandrestraintstrapcleats.Adisadvantageofstainlesssteelconstructionisthatitpredisposesanimalstohypothermia.Thiscanbecorrectedbytheroutineuseofaheatingpadplacedunderthesurgicalpatient.Reusable,easytocleanvinylheatingpadswhichrecirculatehotwaterarefrequentlyusedforthispurpose.Inexpensiveshort-termalternativesincludehotwaterbottlesorheatlamps.Anyheatsourceshouldbeusedwithcautiontopreventpatientburns.

Instrumenttablesprovidethesurgeonreadyaccesstothesurgicalinstrumentsandminimizetheriskofsterilizedinstrumentcontaminationbycontactwithnon-sterilefields.Commerciallyavailableinstrumenttables,suchasMayostands,consistofastainlesssteeltraysupportedbyapedestalbasewithafoot-operatedheightadjustmentdevice,butanytrayarrangementmaybeusedforthispurpose.Theunitshouldbeeasytocleanandsimpletooperate.Thedrapesinaninstrumentpackfrequentlyincludeimpervioustablecoverswhichcanminimizeinstrumentcontaminationandallowthesurgeontorepositionthetablewithoutbreakingaseptictechniqueduringtheprocedure.Surgicalbucketsonwheels(kickbuckets),whichcanbereadilypositionedwiththefeet,areanotherrecommendedpieceofequipment.Theyshouldbeeasytocleanandlinedwithaplasticbagwhichshouldbechangedattheendoftheprocedure.

Adequatelightingisessentialforperformingsurgicalprocedures.Avarietyoffixturescanbeusedtoprovidesufficientlight.Thecommerciallyavailablesurgicallightfixturesmaybeceilingorwall-mountedorfreestanding.Surgicallightsareoftenpositionedabovetheoperativeareaandshouldberegularlywipedwithamoisttowelpriortousetominimizepotentialcontaminationofthesterilefieldbelow.Lightfixturesdesignedwithdetachablesterilizablehandlesallowthesurgeontoadjustthebeamduringsurgery.Wheeled,height-adjustableintravenousdripstandsshouldbeavailablewhenconductingmajorsurgery.CareshouldbetakentoassurethattheI.V.tubingdoesnotcontaminatethesterilefields.PositioningtheI.V.tubingalongtheheatingblankethelpswarmI.V.solutionsbeforeinfusion.

Surgicalsuctionisanotherusefulaccessory.Sterilizedtubingandsuctiontipsareprovidedforuseintheasepticfield.Thetubingisconnectedtoanon-sterilesuctionbottlewhichinturnisconnectedtoabuilt-invacuumline.Ifbuilt-invacuumlinesarenotavailable,portableelectricvaccumpumpsarecommerciallyavailable.

Ancillaryequipmentsuchasrespirators,electrosurgicalunitsandECGmonitorsshouldbeportableandincludedwiththelightfixturesinaroutineequipmentcleaningschedule.Specificdetailsonsuchdevicescouldbeobtainedfromaninstitutionalveterinarianorsurgicalsupervisor.

Surgicalinstrumentationandpackpreparationwillvarywiththetypeandcomplexityofsurgerytobeperformed.Consultationwithaninstitutionalveterinarianorsurgicalsupervisorcouldbehelpfulwhenselectingtheappropriatesurgicalinstrumentsnecessarytoperformaproposedprocedure.Instrumentpacksshouldbedoublewrapped.Variouscommercialmaterialsareavailableforthispurpose.Althoughpackinstrumentpreparationwillbediscussedlater,asmanysterilizableitemsaspossibleshouldbeincluded.Thesemightincludeprepackagedsurgicalblades,sponges,salinebowlsandmiscellaneouscatheters.

Personnel

Aseptictechniquerequirescarefulattentiontoaseriesofstepswhichbeginswithpatientandinstrumentpreparationandendsatfinalwoundclosure.Failureatanyonestepmayresultinwoundinfectionwhichcouldcompromisetheanimal"shealthandtheexperimentaldataderivedfromtheanimal.Aseptictechniquedesignsallactionsandmotionstoprotectthesterilefieldfromcontamination.Thesurgeonandsurgicalsupportstaffmustbeadequatelytrainedtoperformeachstepcorrectly.Acquiringanddevelopingthenecessaryskillstomaintainaseptictechniquerequirespractice.Personnelshouldreceiveinstructionontheindicationsforaseptictechnique,thesourcesofpotentialcontamination,patient,instrumentandequipmentpreparation,sterilizationsystems,gowningandglovingtechniques,andintraoperativeasepticmanagement.Oncethistheoreticalknowledgeisgained,traineescanrapidlylearnbyobservingtheasepticmanagementtechniquesofawell-trainedsurgicalsupportstaff.Traineesshouldpracticeeachstepuntilcorrecttechniquesbecomesecondnature.

Assistancewithemployeetrainingmaybeavailablefromtheinstitutionalveterinarian,amemberoftheanimalcarestaffand/oramemberofahospitalsurgerystaff.

STERILIZATION

Sterilizationistheprocessthatisintendedtokillorremovealltypesofmicro-organisms.Therearetwoprincipalsterilizationmethods:

1)Physical(dryheatorsaturatedsteam)

2)Chemical(ethyleneoxidegasorchemicalliquids).

Factorswhichdeterminethemethodtobeusedarethetypeofmicro-organismsinvolved,thenatureofthearticletobesterilizedandthetimeavailableforsterilization.

PhysicalMethods(Steam)

Steamsterilization(frequentlyreferredtoasautoclaving)dependsontheuseofsteamabove100oC.Temperaturesrangingfrom121-134oCatpressuresof15-30psiaregenerallyrecommended.Thebiocidalactionofmoistheatisadenaturationofmajorcellconstituents.Manysterilizersaredesignedtoprovideanautomaticsterilizationcycle.Inthefirststageofthecycle,airisevacuatedandthechamberbroughttothepre-setsterilizingtemperature,whichismaintainedforaholdingperiodsufficienttokillallmicrobialcontaminants.Minimumholdingtimesforthesterilizationofmedicalequipmentare15minutesat121oC,10minutesat126oC,and3minutesat134oC.Thesteamisthenremovedandinstrumentpacksareallowedtodryorliquidscool.Thedryingstagemaybeadjustedtosuittheload.

Thechamberisthenpressurebytheintroductionoffilteredair.

Therecommendedperiodsofexposurevarywiththenatureofthearticletobesterilizedandthemethodusedtowrapthearticle.Specificdetailsareavailablefromthereferencesattheendofthechapter.

Steamsterilizationhastheadvantageofrapidpenetrationofwrappedmaterialswiththedestructionofallvirusesandbacteria,includingthemostresistantspores.Thesterilizationofdifferentsuppliesismorereadilycontrolledthaninothertypesofsterilizers.Howeveroils,greaseandpowderedsubstancescannotbesterilizedbythismethod.Thesteamautoclavemustbemaintainedingoodrepairandoperatedcorrectlyinordertoperformtospecifications.Sterilizationfailurecanoccurwhenmachinesarenotregularlyserviced.

Steamautoclavefunctionshouldbemonitoredcontinuouslyusingoneormoreofseveralcommerciallyavailableindicatorsystems.Thecolorchangeonachemicaldyeimpregnatedindicatorstripplacedwithinthepackcanprovideaconvenientandrapidvisualcheckthattheappropriatesterilizationconditionswerereached.FunctionshouldalsobemonitoredonaregularbasisusingcommerciallyavailableBIOLOGicalindicators.SporestripsofBacillusstearoThermophilusareplacedwithinthewrappedarticlepriortosterilization.Aftersterilizationthestripisincubatedat57oCfor48hours.Theabsenceofgrowthindicateseffectivesporicidalautoclaveaction.

ChemicalMethods(Gas)

Ethyleneoxidegasiseffectiveagainstalltypesofmicro-organisms.Thebiocidalactionofthisgasisconsideredtobealkylationofnucleicacids.Itisnon-corrosiveandsafeformostplasticandpolyethylenematerials.However,itisnotapplicabletoliquidsortoarticlesinimperviouspackagingmaterial.Itcannotbeusedtosterilizeanimaldietsduetothepotentialtoxiceffectsofthisgas.Itcanalsobeatoxichazardforanimalsreceivingprostheticimplantswhichhavebeensterilizedbythisgas.Theoperatingpressuresandtemperatures(45-60oCand10-12psi)ofethyleneoxidesterilizersareconsiderablylessthanforsteamunits.Articlesshouldbewellaeratedpriortousetominimizethepotentialfortissuetoxicity.Aerationshouldbedoneinamannerwhichminimizesexposureofpersonnel.

Thiscanbeaccomplishedthroughtheuseofself-aeratingsterilizersorseparateaerationcABInets.

Ethyleneoxidegasisapotentialcarcinogenandmutagenandrepresentsapotentialoccupationalhealthhazardforpersonneloperatingsterilizers.Operationofgassterilizersandaeratorsshouldbeinstrictconformancewithmanufacturers"recommendationsandinstitutionalpolicies.Personnelexposureshouldbeminimizedbyappropriateventilationofexhaustgas.Aregularmonitoringprogramforpersonnelshouldbeinplace.

Gassterilizerfunctionshouldbemonitoredcontinuouslyusingoneofseveralcommerciallyavailableindicatorsystems.Thecolorchangeonachemicaldye-impregnatedindicatorstripplacedwithinthepackcanprovideaconvenientandrapidvisualcheckthattheappropriatesterilizationconditionswerereached.FunctionshouldalsobemonitoredonaregularbasisusingacommerciallyavailablebiologicalindicatorsuchassporestripsofBacillussubtiluswhichareplacedwithinthewrappedarticlepriortosterilization.Aftersterilizationthestripisincubatedat37oCfor24hours.Theabsenceofgrowthindicateseffectivesterilization.

Temperature-sensitiveadhesivetapeusedtosecurepackagespriortosterilizationonlyindicatesthatthepackagehasbeenexposedtothesterilizer;thistapedoesnotmonitorsterilizerfunction.

ChemicalMethods(Liquids)

Theuseofchemicalsolutionsasasterilizationtechniqueforsurgicalequipmentisfrequentlyemployed,butitshouldbestressedthatmostsolutionsonlydisinfectanddonotguaranteesterility.Whenthenecessityformaintainingsterilityisacriticalfactor,asintheimplantationofprostheticdevices,indwellingcathetersorvascularaccessports,disinfectioninchemicalsolutionsisnotrecommended.Suchprosthesesshouldbethoroughlysterilizedbyeithergasorsteam.Chemicalsolutions,however,offertheadvantagesofsafetyfordelicateandthermolabileplastics.

Otherlimitationsofchemicalsolutionsshouldalsobeappreciated.Equipmentmustbethoroughlycleanedbeforeimmersion,aschemicalactionisineffectiveinthepresenceofproteinsorfats.Therearecurrentlynoindicatorscommerciallyavailabletomonitortheeffectivenessofthissterilizationmethod.

Alcoholsareneithersporicidalnorviricidal.Theyarenotstableandloseeffectivenessthroughevaporation.Alcoholscannotbeusedforinstrumentsthathaveplasticorcementedparts.

Thechlorinecompoundsexerttheirbiocidalactionbyoxidization.Theformulationswhichrequirethemixingofacidandbasecomponentswithwatertogeneratechlorinedioxide,offertheadvantagesofwidespectrumbiocidalactionandasafealternativetothemorehazardousphenolsorformaldehydes.Theactiveshelflifeofmixedchemicalsisreportedtobe24-48hours.

Ifchemicalsterilizationofinstrumentsisthemethodtobeused,itcanbeperformedincoveredtrayscontainingfreshsolutions.Atwo-traysystem,oneeachforeven-numberedandodd-numbereddays,willensurethatinstrumentshaveafull24-hourcontacttime.

PREPARATIONOFTHEANIMAL

Theanimalsshouldbepreparedinanareaseparatefromwheresurgerywillbeperformed.Preparationisfacilitatedbyfirstinducinganesthesia.Thestomach,rectumandurinarybladdercanthenbeevacuatedasrequiredatthisstage.Hairisthenremovedfromthesurgicalsiteusingelectricclippersequippedwithafineblade.Aliberalareaisclippedtoanticipateanyenlargementoftheinitialsurgicalincisionandminimizewoundcontaminationfromadjacentunclippedareas.Inrodentstheneedtominimizethelossofheatduringsurgeryandrecoverymustbebalancedagainsttheneedtoprovideanadequateasepticfieldwhenclippingtheanimal.Animalhair,particularlyrabbithair,tendstoclogclipperblades.Thiscanbeminimizedbyfrequentcleaningofthebladesandregularlubricationwithacommercialaerosolproductbetweenuse.Avacuumcanbeusedtocleanupafterclipping.Depilatorycreamsmaybeappliedtothesurgicalsite,buttheymaycausecontactdermatitiswhichmayinterferewiththehealingprocess.

Initialskincleaningcanbedonepriortomovingtheanimaltotheoperatingarea.Whentheanimalismovedtotheoperatingarea,itshouldbepositionedonaheatingpadonthesurgicaltable.Toavoidburnsheatingpadsshouldbewrappedtopreventdirectcontactwiththeanimal.Inclinedpositioningwithatilttableisindicatedforsomeproceduresandsomespecies.Thesurgicalapproachwilldictateactualanimalposition;however,someguidelinestoconsiderare:

a.Theanimal"srespiratoryfunctionshouldnotbecompromisedbyoverextensionofforelegsstretchedtowardsthehead,orbyexcessivebodytiltwhichcausespressurefromtheaBDominalorgansonthediaphragm.

b.Limbsshouldnotbeextendedbeyondtheirnormalrangeofmotionandrestraintstrapsshouldbepaddedasneededtopreventimpairedvenousreturninextremities.

c.Aftertheanimalhasbeensecured,anymonitoringdevicessuchasECGelectrodesandesophagealstethoscopesshouldbeplacedandtheirfunctiontested.

d.Ruminantsarefrequentlypositionedonaslightinclinewiththeheaddependent,tominimizethepotentialforaspirationofrumenfluids.Afterintubationwithacuffedendotrachealtube,alargeborestomachtubeisalsofrequentlyplaceddowntheesophagustoremoverumenfluidsandgas.

Theanimalisnowreadyforfinalpreparationofthesurgicalsite.Personnelwhoperformthepresurgicalskinpreparationshouldwearacapandmaskwhenpreparingthesurgicalscrubsuppliesandwhenopeningpre-sterilizedspongeanddrapepacks.Skinpreparationsolutionsmaybeappliedwithasterilespongeheldbyapairofsterileforcepsorbyahandwearingasterileglove.Asterilesurgicalgloveisputononehand,whiletheotherhandisusedtoholdandmanipulatenon-sterilebottlesofsurgicalscrubsolution.Asterilespongeheldintheglovedhandissaturatedwithsurgicalscrubsolutionandthesurgicalareaisscrubbedbeginningwiththecentralincisionsiteandworkingprogressivelyinacircularfashiontothemarginsoftheshavedarea(seeFigure1).Thespongeisthendiscardedandtheprocessrepeated,workingfromthecentertotheoutsidetominimizecontaminationofthesurgicalsite.

Someofthemostfrequentlyusedchemicalsolutionsforpreoperativesurgicalskinpreparationare:chlorhexidine,iodophorsandpovidone-iodinesurgicalscrubs.Recommendedcontacttimesvaryfrom2to4minutes.

Followingremovalofthescrubsolutionwitha70percentalcoholsolutionusingthesametechnique,aniodineskinsolutionispaintedonthesiteusingtheabovetechniqueandlefttodry.

Drapesservetoisolatethesurgicalsiteandminimizewoundcontamination.Drapesshouldbepositionedwithoutthefabricdraggingacrossanon-sterilesurface.Therearetwobasictypesofdrapesystemsused:fenestratedandfourcorner.

Fenestrateddrapeshaveaholeinthemwhichisplacedoverthesurgicalsite.Frequentlyusedforsmallerspecies,thesedrapesareutilizedforroutineelectiveprocedures.Thefenestrationshouldbejustslightlylargerthantheintendedincision.

Thesecondalternativeisthefourcornerdrapesysteminwhichadrapeisplacedateachofthefourmarginsofthesurgicalsite.Fourcornerdrapesareappliedonebyoneinaclockwiseorcounterclockwisedirection.Eachdrapeshouldbecarefullypositionedwitha6to8inchedgefoldedunderneathattheincisionsite(seeFigure2AtoD).Smalladjustmentsinpositioncanthenbemadewithoutcontaminatingtheundersideofthedrape.Drapescanbesecuredinplacewithtowelclampsatthefourcornersoraerosoladhesiveappliedtothemarginsofthesurgicalsitepriortodraping.

Somesurgeonsprefertosecurefourcornerdrapes,thenapplyafenestrateddrapeasasecondlayerofprotection(seeFigure2,EandF).Ideally,thepatientandentiresurgicaltableshouldbedraped,andthedrapeextendedtotheinstrumenttable.Theneedtomonitorthedrapedpatientshouldalwaysbeconsidered.Thesurgeonwhohastoworkaloneoftenhastoassesseyeandjawreflexes,mucousmembraneortonguecolor;thereforetheheadshouldnotbeentirelycoveredbydrapematerial.

Self-adhesivebackedpaperdrapesandclearplasticdrapematerialwithoneadhesivesurfacearealsocommerciallyavailable.

PREPARATIONOFASURGICALPACK

Awell-organizedandconsistentsurgicalpackpreparationsystemcanavoiderrorsandfacilitatesurgery.Instrumentscanbecleanedbyhandorwithanultrasoniccleaningunit.Aftercleaning,eachinstrumentshouldbeinspectedtoensurethatalldebrishasbeenremoved.Afterphysicalcleaning,instrumentscanbedippedinacommercialprotectivelubricantsolutionandallowedtodraindry.Itemsshouldbeassembledonatrayandarrangedinaconsistentorder.Materialsshouldbeplacedinsequentialordersothatitemsusedfirstareplacedontop(seeFigure3).Packsshouldnotbetoodenselypackedintheautoclavetoallowforadequatesteamorgaspenetration.Indicatorteststripscanbeplaceddeepwithinthepack.Packsshouldbedoublewrapped,andtheouterwrapshouldbesecuredwithadhesiveindicatortapeonwhichisrecordedthedateofsterilization.Whenapplicable,thetypeorcontentsofpack(e.g.,laparotomy,thorocotomy)canalsobenotedonthetape.

Notethefollowingpointswhenopeningasterilizedsurgicalpack.Thesterilizationdateshouldbechecked;theshelflifeofwrappedinstrumentsisgenerallyconsideredtobeupto6months.Theadhesiveindicatortapeshouldbenotedfortheappropriatecolorchangeandthepackdescriptionshouldbechecked,whenapplicable.Packsshouldbeplacedonadryinstrumenttrayandtheouterwrappingcarefullyunfoldedbytouchingonlythecornersoftheoutsidedrapesurface.Theoperatorshouldavoidreachingoverthepack.Thepacksshouldnotbeopenedtooearly.Thesurgeonworkingwithoutassistanceshouldopenthepackimmediatelybeforescrubbing.Anyothersterilizedsupplieswhichcanbeopenedontoasterilefieldshouldbemadereadyatthistime.

PREPARATIONOFTHESURGEON

Inalaboratorysetting,theextentofsurgeonpreparationwilldependonthefacilitiesandtheneedforstrictattentiontoaseptictechnique.Well-equippedsurgicalfacilities,inwhichsophisticatedsurvivalproceduresareperformed,generallyrequiresurgeonstowearappropriatesurgicalclothingandtoscrub,gownandglove.Instructioninsuchproceduresshouldbedoneonaone-to-oneorsmallgroupbasisinappropriatelydesignedscrubrooms.Toaugmenttheactualhands-onapproachorwhennecessaryavideotapedemonstrationorpictorialdiagramscanbeused.Readersareadvisedtoconsultthereferencesquotedattheendofthechapterforinstructionaldetails.

Tominimizewoundcontaminationpotential,thesurgeonshouldchangeintosurgicalscrubsandshoesorwearshoecovers.Headcoversandfacemasksshouldcoverallfacialhair.Removeallrings,jewelryandwristwatchesbeforescrubbing.Finger-nailsshouldbetrimmedshortandcleanedwithadisposablenailcleaner.Scrubsinksequippedwithlegorfoot-operatedfaucetsareideal.Regularfaucetsmustbeturnedon,adjustedandnottouchedagain.Thehandsandforearmsarewashedfor30to60secondswithasurgicalscrubsoap.Thenasterilebrushisusedtomethodicallyscruballsurfacesofthehands,fingersandforearmsdowntotheelbows.Botharmsarerinsedandtheprocessrepeatedstartingwithfingertipsworkingdowntotheelbows.Thedefinitionofa"completesurgicalscrub"iscontroversial.However,contacttimesof3to15minutesand/or5to20strokespersurfacearefrequentlyrecommended.

Afterrinsing,thehandsareheldtogetherhighandrinsewaterallowedtodripfromtheelbows.Thisminimizesthecontaminationofhandsbywaterdrippingfromthenon-sterileupperarmareas.Thesurgeonshouldavoidtouchinganythingatthisstageexcepttodrythehandswithasteriletowel.Nextthesterilegowniscarefullyremovedfromthepacktoavoidtouchingtheoutsideofthegown.Itisheldawayfromthebodyandshakenout.Thesleeveholeislocatedandeacharminsertedinturn.Correctgowningrequiresanassistanttotiethebackofthegownattheneckandwaist(beingcarefultotouchonlytheinnergownsurface).

Sterilesurgicalglovesarepackagedwiththecuffofeachgloveturneddown.Thisallowstheglovestobeputonwithoutthebarehandsevertouchingtheoutsidesurfaceoftheglove.Onegloveispickedupbytheturned-downcuffandpulledontothehandwiththecuffleftturneddown(seeFigure4-1and2).Usingtheglovedhand,pickuptheremainingglovebyinsertingthefingersintothecuffandpullingitontotheoppositehand(seeFigure4-3).Thentheglovecuffisliftedoverandontothegowncuffandtheprocessrepeatedontheotherhand(seeFigure4-4,-5,-6).Thistechniqueisknownas"opengloving."Analternativeandmoredifficultmethodisclosedgloving,descriptionsofwhichcanbefoundingeneralsurgicaltexts.Removethepowderontheouterglovesurfacebywipingtheglovedhandswithadampsterilegauze.Armsandhandsshouldbeheldabovethewaistatalltimes.Aseptictechniqueismaintainedwhenthegownedandglovedsurgicalteamonlytouchessterilizedequipmentwithinthesterilefield.

Thesurgeonworkingalonefaceslogisticalproblemswhenattemptingrigidasepticprotocolasdefinedabove.Aproposedpracticalsequenceofstepstominimizeerrorsispresentedasfollows:

1.Assembleallsterilizedsupplies.

2.Changeintoscrubs.

3.Setuptable,heatpadsandgasmachines,checkequipment.

4.Weighanimal,induceanesthesia.Prepareanimalbyhairclipandshave,cathetersplacedasrequired.

5.Positionandsecureanimalonthetable.

6.Connecttogasmachine,connectaccessorymonitors.StartI.V.linesasrequired.

7.Makecertainthatastableanestheticplaneisattained.

8.Putoncap,mask.Opensterileinstrumentandpreppacks.

9.Usingonesterileglove,preparesurgicalsitewithscrubsolutions.

10.Putonnewsterilegloveanddrapepatient.

11.Removegloves.Recheckstableanestheticstate.Opengloveandgownpacksifnotincludedininstrumentpack.

12.Performsurgicalscrub.

13.Putongownandgloves.

14.Startsurgery.

SUMMARY

Thepracticeofaseptictechnique,whenperformingsurvivalsurgicalprocedures,minimizesthechancesthatanimalhealthorexperimentaldatawillbecompromisedbypost-surgicalinfections.Aseptictechniquesrequirethatappropriatefacilitiesandequipmentbeavailableandthatthepersonnelinvolvedbeadequatelytrained.Thekeyelementinmaintaininganasepticenvironmentiswell-trainedpersonnelwhounderstandtheprinciplesofaseptictechniqueandutilizethisknowledgeonanongoingbasis.

REFERENCES

AnimalWelfareAct(Title7U.S.C.2131-2156)asamendedbyPL99-198,December23,1980.

Lang,C.M.AnimalPhysiologicSurgery.Springer-Verlag,NewYork,1976.

Leonard,E.P.FundamentalsofSmallAnimalSurgery.W.B.Sanders,Philadelphia,1968.

Knecht,C.D.,Allen,A.R.,Williams,D.J.,etal.FundamentalTechniquesinVeterinarySurgery.W.B.Sanders,Philadelphia,1981.

Gardner,J.F.andPeel,M.M.IntroductiontoSterilizationandDisinfection.ChurchillLivingstone,Melbourne,1986.

McCredie,J.A.andBurns,G.P.(eds.),BasicSurgery.MacMillanPub.Co.,NewYork,1986.

Banerjee,K.andCheremisinoff,P.N.SterilizationSystems.TechnomicPublishingCompanyInc.,Lancaster,PA;1985.

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