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DigitalInstantDownload Author(s):RupenDattani,RidzuanFarouk
ISBN(s):9780521699037,0521699037
Edition:Kindle
FileDetails:PDF,2.32MB
Year:2007
Language:english
PrinciplesofSurgeryVivasfortheMRCS WrittenbyanexamineratboththeLondonandGlasgowCollegesof SurgeryandasuccessfulrecentMRCScandidate, PrinciplesofSurgery Vivas fortheMRCS providesreaderswithsamplevivaquestionsto enablethemtopreparefullyforthissectionoftheexaminations.
In A–Zformatforquickreference,thisbookwillbeinvaluableto MRCScandidates,undergraduatemedicalstudentsandthosesitting theFRCOGexaminations.Itwillalsoserveasavaluable‘aide m ´ emoire’fortrainingsurgeonsordoctorsatalllevelsofexperience, especiallythosetrainingjuniorstaff.
RupenDattani isaSpecialistRegistrarinTraumaandOrthopaedicsin theSouthWestThamesRotation.
RidzuanFarouk isaConsultantColorectalSurgeonatRoyalBerkshire Hospital,Reading.
Principlesof SurgeryVivasfor theMRCS RUPENDATTANI RIDZUANFAROUK cambridgeuniversitypress
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Thispublicationisincopyright.Subjecttostatutoryexception andtotheprovisionsofrelevantcollectivelicensingagreements, noreproductionofanypartmaytakeplacewithout thewrittenpermissionofCambridgeUniversityPress.
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PaediatricSurgery204
PerioperativeMonitoring212
PeripheralVascularDisease214
PhysiologicalResponsetoSurgery220
PositioningofPatients224
Post-operativeCare227
Post-operativeComplications230
Pre-admissionClinics233 Pregnancy235 Pre-medication238
Pre-operativeInvestigations240 PreparationforSurgery243
ProstateCancer245
Acknowledgements Iam eternallygratefultomyfamilywhosecontinuallove, supportandencouragementhavehelpedmeachieveallI haveinlife.IwouldliketodedicatethisbooktoSunny,atruly missedfriendwhoseenthusiasmandloveforliferemainmy constantsourceofinspiration.
R.D.
■ AbdominalAorticAneurysm (AAA) Defineanabdominalaorticaneurysm
It isanabnormalpermanentlocaliseddilatationoftheaorta havingatleasta50%increaseindiametercomparedwiththe expectednormaldiameter.Itisusuallyregardedasadiameter >3 cm.
WhatistheaetiologyofAAA? Hypertension
Peripheralvasculardisease
Hyperlipidaemia
Diabetesmellitus
Increasingage
Sex(M:F = 4:1)
Familyhistory
WhataretheclinicalfeaturesofAAA?
Asymptomatic(75%)
Symptomatic: pain:epigastricorback rupture distalembolus
fistula:aorto-caval;aorto-intestinal systemicillness(inflammatoryaneurysms)
WhatisthenaturalhistoryofAAA? Theriskofruptureincreasesasaneurysmexpands.Growth isusuallyat10%/yr.The5-yearriskofruptureis15%for aneurysms <4cm,thisincreasesto >75%foraneurysms >7 cm.Overall,onlyabout15%ofallAAAeverrupture,the remainderdiefromunrelatedcauses.Theoverallmortality fromaruptureis80%–90%.
WhatistheroleofscreeninginAAA? Pilotschemeshaveshownthatscreeningforasymptomatic AAAcanreducetherateofrupturebyalmost50%.Highrisk patients,e.g.hypertensivemales >65couldbetargetedfor suchscreeningprogrammes.Patientswithsmallaneurysms couldundergoregularUSSsurveillance.Amulticentre screeningprogrammestudyiscurrentlyunderwayto determinethefeasibilityofanationalscreeningprogramme.
BrieflydescribetheUKsmallaneurysmtrial
Thistrialrandomised1090asymptomaticinfra-renalsmall aneurysms(4.0–5.5cm)inpatientsagedbetween60and76to operateorbekeptunderregularultrasoundsurveillance. Therewasnodifferenceinmortalityratesfromearlysurgical repaircomparedwith6-monthlyultrasoundsurveillance. Annualrupturerateinthisstudywas1%.Surgicalintervention wasusedwhenoneofthefollowingthreecriteriawasmet.
Rateofexpansion >1cm/yr
Aneurysmdiameterexpansion >5.5cm
Aneurysmbecamesymptomaticortenderonpalpation
Whataretheindicationsforsurgeryinpatients withAAA?
Emergencyrepair: Rupture
Rapidlyexpanding(>1cm/yr)aneurysmthatis symptomaticorclinicallytender
Electiverepair:
Aneurysms >5.5cmindiameter
Symptomaticaneurysm
Rateofexpansion >1cm/yrthatisasymptomaticand non-tender
Howshouldpatientswithsmalleraneurysms bemanaged?
Aneurysm <4 cm:yearlyUSSsurveillance
Aneurysm4–5.5cm:6-monthlyUSSsurveillance
WhatarethesurgicaloptionsinthetreatmentofAAAs?
Endoluminalrepair:trans-femoralortrans-iliacplacement ofprostheticgraftunderfluoroscopicguidance.Thethree maintypesofgraftare:aorto–aorto,aortobi–iliacand aortouni–iliacwithafemoral–femoralcrossover.Requires CTorIADSAtoevaluatethemorphologyoftheaneurysm priortotheprocedure.About1–1.5cmofhealthyaorta distaltotherenalarteriesand1cminthecommoniliac arteriesrequiredforsufficientclearance,thereforeonly about40%ofaneurysmssuitableforthistypeofrepair. Successfulstentingassociatedwithreducedaneurysm expansion.Patientsrequirepost-procedureCTtodetectfor endoleaks,whichcancauseruptures.Othercomplications includegraftmigrationanddisplacement,graftocclusion, infection,embolisationandgraftkinking.
Openrepair:durablesyntheticmaterials,e.g.Dacron® used forrepair.Mortalityratebetween2%and5%andrisesto 10%forpatientswithassociatedco-morbidity.Specific complicationsinclude: immediate:bleeding,embolism,arterialthrombosis early:acuterenalfailure,CVA,MI,mesentericinfarction, spinalcordischaemia late:graftinfection,falseaneurysm,aorto-entericfistula
■ AbdominalPain Whatarethecommoncausesofacuteabdominalpain?
Non-specificabdominalpain
Appendicitis
Intestinalobstruction
Biliarytractdisease:cholelithiasis,choledocholithiasis, calculus,cholecystitis,ascendingcholangitisandgallstone ileus
Diverticulardisease:painfuldiverticula,diverticulitis, perforateddiverticula
Pepticulcerdisease
Pancreatitis
Constipation
Inflammatoryboweldisease
Irritablebowelsyndrome
Bacterial/viralgastroenteritis
Irritablebowelsyndrome
Abdominalaorticaneurysm:seenmainlyinelderlypatients
Malignancy:highincidenceinelderly
Mesentericischemia
Urologicalcauses:UTI,calculi,testiculartorsion
Medicalcause: myocardialinfarction
pneumonia
Gynaecologicalcausesofabdominalpain
ectopicpregnancy
pelvicinflammatorydisease
endometriosis
rupturedovariancyst
Whichinvestigationsmaybeusefulinthediagnosisof abdominalpain/masses?
CXR:helpfulinexcludingpneumoniaandfree intraperitonealairunderthediaphragminpatientswith rupturedviscus
AXR:itisoflimiteduseintheyoungpatientbutmayshow airwithinanabscessorasaresultofintestinalobstruction orperforation;calciumdepositionmaybeseeninchronic pancreatitisandcalculi(renalorbiliary);latefindingsof mesentericischaemiaoccasionallyobserved(i.e. pneumatosisintestinalis)
Ultrasound:doesnotinvolveradiationbutlimitationstouse include:obesity,poorimagesinthepresenceofgasandis operatordependent.Canbeusedto: identifynatureoflesion:cysticorsolid determinevascularityofamass(Doppler) guidebiopsyofamass identifylivermetastases
CT:significantradiationbutrapidresults,notoperator dependentandnotinfluencedbypresenceofgas.Uses include: differentiatingcystsfromabscesses stagingofcancers diagnosingintra-abdominallymphadenopathy highsensitivityfordiverticulitis instablepatientswithsuspectedAAA
CTwithangiography:forsuspectedmesenteric ischaemia
Doublecontrastbariumenema:indicatedifamassis thoughttoarisefromthelargebowel,e.g.cancers,polyps, diverticulardisease,inflammatoryboweldisease (‘cobblestoning’orskiplesions)
Instantenema:indicatedforacutelargebowelobstruction
Bariummealandsmallbowelenema:formassesarising fromthestomachorsmallbowel
IVU:forsomeurologicalcausesofabdominalpain
Radioisotopeimaging:usedwhenothermodalitieshavenot confirmeddiagnosis.
MRI:usedinpelvicmassesandliverlesions
■ Abscesses Whatisanabscess? Anabscessisaloculatedorlocalisedcollectionofpus surroundedbygranulationtissue.Itusuallycontainsbacteria orotherpathogens,inflammatorycells,necrotictissueand proteinexudates.Itcanbesuperficial(e.g.pilonidal,breast) ordeep(e.g.diverticular,subphrenic).
Whataretheclinicalfeaturesofanabscess? Localisedinflammation
‘Pointing’(thetrackingofanabscesstoanexternalsurface)
Dischargeofpus(purulent)orpusmixedwithblood (haemopurulent)
Onexamination:
locally:swelling,centraltenderness,fluctuantmass generally:pyrexia,tachycardia,sepsis
Whichgroupofpatientsareatparticularriskof abscessformation?
Immunocompromisedpatients
Sicklecell
Peripheralvasculardisease
Inflammatoryboweldisease
Severetrauma
Abscesscavitiesareimpervioustoantibioticsandinfact prolongedantibiotictreatmentcanresultinachronic
inflammatorymass(an‘antibioma’).Allabscessesshould thereforebedrained.
Howcanabscessesbedrained? Aspiration:abscessesfilledwithfluidcanbeaspiratedwitha largeboreneedleandtheprocessrepeatedifnecessary.This methodshouldonlybeusedifthereisnocontinuingcause found
Opendrainage:superficialabscessescanusuallybedrained throughacruciateincision;thepussentformicrobiology; loculibrokendownandnecrotictissueexcised.Thewound shouldbeleftopenandpackedwithanappropriatedressing Percutaneousdrainage:deepabscesscanbedrainedby fluoroscopic,ultrasoundorCTguidedaspiration.Atubecan beleft insitu toallowdrainageoffluid
■ AlcoholandSurgery Whichsurgicalspecialitiesmightbeinvolvedinthe managementofpatientswithexcessivealcohol consumption?
Generalsurgery:
Mallory–Weisstear oesophagealvarices
oesophagealcarcinoma
gastritis,gastricerosionsandulcers
gastriccarcinoma
acuteandchronicpancreatitis
pancreaticcarcinoma
livercirrhosis
hepatomegaly
splenomegaly,hypersplenism
hepatocellularcarcinoma
Traumaandorthopaedics: roadtrafficaccidents
fragilityfractures:alteredcalciummetabolismcauses osteoporosisthusincreasingtheriskoffractures
alcoholicmyopathy:characterisedbypainfulandswollen muscles
ENT: laryngealcarcinoma
pharyngealcarcinoma
Neurosurgery: headinjurywithintracranialbleeding
Urology: impotence
testicularatrophy
ObstetricsandGynaecology: irregularmenses
fetalalcoholsyndrome
Whatarethepotentialproblemsofsurgeryinpatients withexcessivealcoholconsumption?
Pre-operatively:
Obtainingadetailedhistorymaybedifficultduetomemory loss,confabulations,cerebellardegeneration,Korsakov’s psychosisorWernicke’sencephalopathy
Nutritionaldeficienciesarecommoneveninwell-nourished alcoholics: vitamins:thiamine,folate,pyridoxine,nicotinicacid, vitaminA
electrolyteimbalance:lowserumlevelsofpotassium, magnesium,zinc,calcium,phosphorus
Patientsaremorelikelytohavealcohol-inducedmedical problems:
cardiovascular:hypertension,arrhythmias(especially atrialfibrillation),cardiomyopathy,heartfailure, muralthrombusformation,cerebrovascular accidents
respiratory:bloodflowtothelungsmaybeimpededin chronicalcoholicswithcirrhosisoftheliverwhocanhave upto30%oftheircardiacoutputshuntingrighttoleft, therebydecreasingoxygenation;alcoholicsfrequently havepulmonaryaspirationduetocentralnervoussystem depressionwhenintoxicated,leadingtoaspiration pneumonitis
renal:alcoholexertsadiureticeffectbyinhibitingthe secretionofADH;serumsodiummaybeincreasedand potassiumdecreasedinchronicalcoholicswithincreased totalbodywatercontent
endocrine:glucoseintolerance,transienthypoglycaemia
haematological:macrocyticanaemia,thrombocytopenia, prolongedprothrombintimeandpartialthromboplastin time
Druginteractions: accelerationofhepaticmicrosomalmetabolismofcertain drugs,e.g.warfarin,hypnoticagents,antidepressants, antihistaminesandhypoglycaemicdrugs liverpathologymaydepressmetabolismandslowthe clearanceofdrugsfromtheliver,thusincreasingthe half-lifeofcertaindrugsadministeredtothepatient
Operatively:
Excessivebleedingdueto: alteredliverproductionofclottingfactorsII,V,VII,Xand XIII portalhypertension decreasedplateletaggregation inhibitedthromboxaneA2production,whichisrequired forclotting
Post-operatively:alcoholicshaveahigherincidenceof: pulmonaryinfection:alcoholinhibitsciliaryactivity, macrophagemobilisationandsurfactantproduction woundinfectionsduetodecreasedproductionofwhite bloodcellsandreducedgranulocytemobility anastomoticleakages
Whatisalcoholwithdrawalsyndrome? Alcoholwithdrawalsyndromeoccurswhenpatientswhohave ethanol-inducedcellulartolerancetoalcoholstopdrinking. ThesymptomsareduetothesuddenwithdrawaloftheCNS depressanteffectsofalcoholandcanrangefromamild hangovereffecttolife-threateningseizures.Clinicalfeatures ofwithdrawalincludeatremorofthehands,autonomic nervoussystemdysfunction(e.g.increasesinpulse, respiratoryrate,temperatureandbloodpressure,insomnia
andnightmares,anxietyorpanicattacks)andGIdisturbance. Symptomscommencewithin0to5hoursofreducingalcohol intake,peakinintensityonday2or3andusuallybeginto improvebythefourthorfifthdayofwithdrawal.About5%of patientsinwithdrawalexhibitseveresymptoms,e.g.delirium tremens(aconfusionalstateaccompaniedwith hallucinations)orgeneralisedseizures.
Preventionofalcoholwithdrawalisimportantinthepatient undergoingsurgeryandinthepost-operativeperiod.
Benzodiazepines(e.g.Chlordiazepozideordiazepam),alphaagonistsandcarbamazepinehavebeenshowntodecreasethe incidenceofwithdrawalincludingseizures.Betablockerscan beaddedtopreventautonomicdysfunction.
■ Amputation Whatarethemainindicationsforamputationsurgery?
3 Ds: dead,deadlyordisabled.
Dead(gangrene)
vasculardisease(arterialorvenous) diabetesmellitus infection
Deadly(tumour) Disabled trauma congenitaldeformity
Whatarethecontraindications?
Jointcontracturesaffectingthehipand/orknees
Severeosteoarthritis
Spasticityorparalysisofthelowerlimbs
Sensoryneuropathyaffectingtheskinofthefuture stump
Howcanamputationsbeclassified?
Major:
lowerlimb:hindquarter,hipdisarticulation,above-knee, throughknee,below-knee
upperlimb:forequarter,shoulderdisarticulation,upper arm,forearm
Minor:
lowerlimb:toe,Ray,transmetatarsal,midfoot,ankle upperlimb:digit,Ray
Whatfactorsinfluencethelevelofamputationto beperformed?
Viabilityofsofttissues
Vascularviability:thiscanbeassessedclinically(skin colour,atrophicchanges,temperature)orusingspecific investigations,i.e.Dopplerscans,transcutaneousPO 2 measurementorisotopemeasurementofskinblood flow
Viabilityofunderlyingbone:X-raysshouldbetakeninat leasttwoplanes
Underlyingpathology
Functionalrequirement
Abilityofthepatienttorehabilitate
Comfort
Cosmeticappearance
Whatarethegeneralprinciplesofamputationsurgery? Pre-operative:
Multidisciplinaryapproachwithinputfromthesurgeon, anaesthetist,physicianinrehabilitationmedicine,nursing staff,physiotherapists,occupationaltherapists,prosthetic specialistsandpsychologists
Assessmentofthelevelofamputationtobeperformed: comprisesclinicalassessmentandadjunctiveinvestigations Considerepiduralanalgesiapre-operatively(whichcanbe continuedtothepost-operativeperiod)asitsignificantly reducespost-operativephantompain
Antibioticprophylaxis
Avoidtheuseoftourniquetsinvasculardisease
Operative:
Thetotallengthoftheflapshouldbeapproximatelyoneand a halftimesthediameterofthelegatthelevelofbone resection
Bloodvesselsshouldbedissectedandseparatelyligatedto preventthedevelopmentofarteriovenousfistulasand aneurysms
Nervesshouldbedividedundertensionandproximaltothe bonesectiontoavoidneuromaformation
Removeanybonyprominencesarounddisarticulations
Muscle(assessviability)shouldbeusedtocoverthecutend ofbones
Avoidexcessivesofttissuewithinthestump Tension-freeclosure
Considertheuseofadrainespeciallyformajoramputations
Post-operative:
Stronganalgesiaisessentialastheseproceduresare painful
Earlyphysiotherapy:topreventflexioncontractures,build musclepower,preventstumpoedemaandtocommence earlymobilisation
Useof earlywalkingaids(prosthesis):allowsthepatientto standandcommencewalkingwiththephysiotherapist
Supportgroupscanbebeneficial
Whatarethepostoperativecomplicationsof amputationsurgery?
Early: infectionofthesofttissues
haematomaatstumpsite
woundbreakdown
flexioncontractures
DVT/PE
Late: phantomlimbpain causalgia
infection(includingosteomyelitis) ischaemia ulceration
boneerosionthroughtheskin
■ AnaemiaandSurgery Defineanaemia
Hbconcentration <14g/dlinmenand <12g/dlinwomen.
Whatistheidealperioperativehaemoglobin concentrationinanaemicpatientsundergoingsurgery?
For optimaltissueoxygendeliveryanHbof10–11g/dlis required.
Whymightitbeimportanttocorrectchronicanaemia priortosurgery?
Anaemicpatientshavereducedcapacitytocompensatefor intra-operativebloodloss
Anaemiareducestissueoxygenationdueto: shiftingofHbdissociationcurvetotheright reductioninplasmaviscosity
localtissueacidosis
peripheralvasodilation
Whenshouldpatientsbetransfusedinthe preoperativeperiod?
Thereisnotasinglefigureatwhichtransfusionshouldbe commenced.Adecisiontotransfuseshouldbemadeby determiningtheminimalHbconcentrationthatwillprovide adequatetissueoxygenationforthatindividual.
Howmuchwillthehaemoglobinconcentrationrise aftertransfusionofoneunitofredcells?
In anaverage70kgadult,Hbconcentrationwillriseby 1.1g/dl.
Whataretheproblemswithpreoperativeallogenic bloodtransfusion?
ElevationofHbconcentrationsto‘normal’levelscan worsenheartfailureandcausecardiacfailure
Bloodtransfusedimmediatelypriortosurgeryhasreduced O2 carryingcapacity
Pre-operativetransfusionmayinduceimmunosuppression
Increasedriskofpost-operativeinfectionespeciallyin orthopaedicpatients
Increasedriskoftumourrecurrenceanddeath
Increasedhospitalstay
Iftransfusionisrequiredwhenshoulditbegiven? Ideally,itshouldbegivenatleast2daysbeforesurgery.
Whatarethealternativestoallogenicblood transfusion?
Drugtherapy:
haematinics,i.e.ferroussulphateorrecombinanthuman erythropoietin(EPO)administeredafewweekspriorto surgerycanincreasetheredcellmassandhaematocrit withareductionintheneedforintra-operative transfusion
anti-fibrinolytics(e.g.tranexamicacid)haveprovento reducebloodlossduringcardiacandlivertransplantation surgery
Pre-operativeautologousblooddonation(PAD):shouldbe consideredifthereisalikelihoodofatleast2unitsofred cellsbeingrequiredforintraoperativetransfusion.Average donationis1unit/wkthereforenotsuitableforemergency surgery
Acutenormovolaemichaemodilution:atthestartofsurgery bloodisremovedfromthepatientandthevolumereplaced withintravenousfluid.Thecollectedbloodcanbe
transfusedattheendofsurgeryorasrequiredintraoperatively
Intra-operativecellsalvage:batchedorcontinuous processingofbloodcollectedduringsurgerywhichcanbe transfusedbackintothepatient
■ Anastomoses Whatarethebasicprinciplesinperformingany gastrointestinalanastomoses?
Pre-operatively:
Optimisationofanyco-existingmedicalconditions
Bowelpreparation:toreduceintraoperativeperitoneal contamination
Nutritionalsupplementation
Prophylacticantibiotics
Operatively:
Adequateexposure
Carefulassessmentoftheextentofresectionrequired: ensurebothendsoftheboweltobejoinedhaveagood vascularity
Minimiseriskofinfection: isolatethecutendsofbowelwithantiseptic-soakedswabs useofpolythenewoundprotectorsmayhelpprevent contaminationofwoundedges cleanopenendsofthebowelwithantiseptic-soaked swabs afterinstrumentshavebeenusedforananastomosis,they shouldnotbeusedagain,e.g.forwoundclosure
Suturingduringformationofananastomosisshouldbe suchthat: thebowelisnotrenderedischaemic(nottoomany sutures!) theknotsarenotover-tightened thesuturesareequallyspaced theboweledgesareapproximatedandinverted
Anastomosesshouldbe: tensionfree watertight freeofforeignmaterial
At theendoftheprocedureensurethat: thebowelislyinguntwistedandwithouttension thereisanadequatelumen anymesentericdefectisrepaired Consideraproximaldefunctioningstomaespeciallyifa highriskofanastomoticleakageisanticipated.Thisis particularlyrelevantifalow,colo-rectalorcolo-anal anastomosishasbeenperformed.Insuchcases,formation ofaloopileostomycanbeconsidered(integrityof anastomosisisconfirmedwithacontraststudy,6–8weeks post-surgery,beforethestomaisreversed)
Post-operatively:
Anastomosishealingcanbeoptimisedby: ensuringoptimisationofthepatient’sgeneralcondition preventinggeneralisedhypoxia(thiswillcausetissue hypoxia) preventinghypovolaemia(thiswillreducesplanchnic bloodflowandinturn,willleadtoanastomoticfailure)
Afteranoesophago-gastricoroesophago-jejunal anastomosis,manysurgeonswillperformwater-soluble contraststudiespriortocommencingoralintake Alwaysbevigilantforsignsofananastomoticleak
Whatarethedifferenttechniquesofperforminga gastrointestinalanastomosis?
Anastomosescanbefashionedinthreeways: endtoend endtoside sidetoside
Handsewn:
single-layered:strongsubmucosallayerwithminimal damagetosubmucosalbloodvessels;interrupted seromuscularabsorbablesuture
two-layered:serosalappositionandmucosalinversion; innercontinuousandouterinterruptedsuture
Stapled: side-to-sideanastomoseswithlinearstaples end-to-endanastomoseswithcirculardevices
Howdoanastomosesheal? Lagphase(day0–4):inflammatoryphase;anastomoses haveminimalstrength
Fibroplasiaphase(day4–14):immaturecollagenlaiddown; anastomosesstillweak
Maturationphase(afterday10):collagenremodels; anastomosesstrengthen
Whydogastrointestinalanastomosesfail? Poorpatientselection:
immunocompromisedpatients,e.g.malnutrition, corticosteroidtherapy,jaundice,sepsis,uraemia
Poorpreparationoftheintestinefortheanastomosis: bowelendswereofpoorvascularity therewasdistalobstruction
Poorsurgicaltechnique: bowelendsundertensionduringanastomoses suturesnottiedcorrectlyorknotstiedtootightly renderingthebowelischaemic mesentericdefectsnotrepaired peri-anastomotichaematomaformation
Poorpost-operativecare: hypoxiaorhypotensionleadingtotissueischaemia
Whatarethesignsofanastomoticleakage? Intra-luminalcontentsinadrain
Sepsis
Peritonitis
Fistulaformation
Unexplainedpyrexiaorelevatedwhitebloodcount
Prolongedileusorachestinfectiondevelopingatalater thanusualstage
Progressisslowerthanexpected
Howdoesvascularanastomosisdifferfrom gastrointestinalanastomosis?
In ordertoapposetheinnerendotheliallayers,vascular anastomosismustbeperformedbyeversionandnot inversionasisthecaseforintestinalanastomosis.Failureto dothiswillallowclotstoformattheanastomosisandocclude thelumen.Forverysmallvessels,eversionisnotpossibleand sotheanastomosisisperformedsuchthattheendsare united,edge-to-edgeusingaseriesofinterruptedsutures.
■ AntibioticProphylaxis Whatistheaimofantibioticprophylaxis?
It istopreventbacteriafrommultiplyingwithoutalteringthe normaltissueflora.
Whataretheindicationsforantibioticprophylaxis?
Generalindications:
whenaprocedurecommonlyleadstoinfection,e.g. colectomy
whenantibioticprophylaxishasbeenshowntobeofproven valueinreducingpost-operativeinfectionsfrom endogenoussources
whenresultsofinfectionwouldbedevastatingdespitethe lowriskofoccurrence,e.g.insertionofmetallicprosthesis immunocompromisedpatients
urinarycatheterisationinpatientswithprostheticjoint implantsorheartvalves
removalofaurinarycatheterinallpatients
surgeryinpatientswithvalvularheartdiseaseorprosthetic heartvalvestopreventendocarditis
Urologicalsurgeryinpatients:
requiringinstrumentationoftheupperurinarytract withknownurinarytractinfection withpotentiallyinfectedurine(urinarycalculidiseaseor catheterisedpatients)whoareatgreaterriskofinfection withurinarytractinfectionandwhoareknowntohave valvularheartdiseaseorprostheticheartvalves athigherriskofsystemicinfection,e.g.diabetics,patients withcongenitalcardiacdisorders,patientswithacardiac pacemakerormetallicorthopaedicimplants
Whenandhowshouldantibioticprophylaxis beadministered?
Intravenously,usually1hbeforesurgeryoratinductionof anaesthesiaandatleast5minutesbeforeinflationofa tourniquet.Seconddoseshouldbegivenifsurgerylasts >4h orifthereissignificantbloodlossorhaemodilution,to maintainadequatetissuelevels.Itcanbegivenasasingle dose(ifpost-operativeinfectionrateis3%–6%)ormultiple doses(ifpost-operativeinfectionrate > 6%).
Whatfactorsinfluencethechoiceofantibioticused?
Allhospitalsshouldhaveantibioticprophylaxisprotocolsin placethatmustbereviewedandupdatedregularly.Factors thatinfluencethechoiceofantibioticusedare:
siteofsurgery:differentbodysiteshavedifferentbacterial flora
sensitivitytoencounteredorganisms sideeffects geographicalresistancetoorganisms
■ AnticoagulationTherapy andSurgery Whenisitsafetoperformsurgeryinpatients onwarfarin?
SurgeryisnormallysafewhentheINRislessthan1.2.
Howshouldpatientsonwarfarinbemanagedpriorto electivesurgery?
Warfarinshouldbestopped4–5daysbeforesurgery
IntravenousheparininfusioncommencedoncetheINRis <2or24 hoursafterthelastdoseofwarfarinforpatientsin whomanticoagulationiscritical(e.g.patientswith mechanicalheartvalves)
APTTmeasuredregularlyandbekeptinthetherapeutic range(2–3)
Heparinshouldbestopped6hoursbeforesurgery,atwhich timetheAPTTratioshouldbe <1.5
Immediatelyaftersurgery,heparininfusionshouldbe restartedandwarfarincommencedoncethepatientis eatingnormally.HeparinisstoppedoncetheINRis >2
Howshouldpatientsonwarfarinbemanagedduring emergencysurgery?
Pre-operatively,10mgintravenousphytomenadione (vitaminK1 )is givenfollowedby15ml/kgfreshfrozen plasma
Coagulationprofileshouldbemeasuredduringsurgeryand FFPinfusionrepeated
Whatistheproblemwithphytomenadione (vitaminK1 )treatment?
Patientsmayberesistanttore-warfarinisationforupto 4weeksfollowingadministration
Isitimportanttomeasuretheactivityoflowmolecular weightheparintreatment(LMWH)?
No. AlthoughLMWHactivitycanbeassessedbymeasuring FactorXalevels,thisisnotrequiredasthebioavailabilityof thesedrugsismorepredictablethanthatofunfractionated heparin.LMWHshouldbestopped12hoursbeforesurgery.
Whatistheeffectofantiplateletagentsonsurgery? Antiplateletagentssuchasaspirinanddipyridamolewilllead toprolongedbleedingwhichcanbeseenupto2weeksafter cessationoftreatment.Insometypesofsurgery,i.e. neurosurgery,theseagentsarestoppedroutinelypriorto operation.
■ AssessmentforFitness for Anaesthesia Whatisthesinglemostimportantfactorwhich influencespost-operativemortalityrates?
TheNationalConfidentialEnquiryintoPerioperativeDeath (NCEPOD)identifiedsub-optimalpre-operativepreparation ofpatientsastheleadingfactor.
Whatarethemostcommonreasonsforcancellationof anoperationonthedayofsurgery?
Onsetofnewmedicalcondition
Insufficientoptimisationofco-existingconditions
Inadequateinvestigationsofco-existingconditions
Lackofcriticalcarebeds(lesscommonthanabovethree factors)
Howcancancellationratesbereduced?
Pre-operativeassessmentclinicsrunbyanaesthetists todealwithpatientswithcomplicatedmedical histories
Earlyreferraltomedicalspecialiststoassessifthepatient’s conditioncanbeoptimisedpriortosurgery
Whichmedicalconditionsarecommonlysub-optimally controlledpriortosurgery?
Cardiac
Respiratory
Renalfailure
WhatistheASAgradingsystem? TheAmericanSocietyofAnesthesiologists(ASA)gradeisthe mostcommonlyusedgradingsystem,whichaccurately predictsmorbidityandmortalityassociatedwithanaesthesia andsurgery.
ASAGradeDefinitionMortality(%)
INormalhealthyindividual0.05
IIMildsystemicdiseasewithnofunctional limitation
IIISeveresystemicdiseasewithfunctional limitation
IVSeveresystemicdiseasewhichisa constantthreattolife
VMoribundpatient,notexpectedto survive24hourswithorwithoutsurgery
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