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AnaesthesiaforMedicalStudents‐ReviewQuestionsChapter3:Preoperativeassessment**Problemidentification

• Cardiovascular:ischemicheartdisease→riskformyocardialischaemia/infarctioninperiopperiod

o Hxforstabilityofangina,exercisetoleranceo Considerationofvalvularheartdisease,arrhythmias,hypertension

• Respirology:cigarette,(stopfor8weeks,butstoppingfor24hstillimpartsbenefits)o COPD→↑riskrespcomplications;asthma→bronchospasm;ensurenoacute

URTIo ExercisecapacitybyHx;restrictivelungdz,alteredcontrolofbreathing

• Neuromuscular:intracraniallesion→seeksignsof↑edICP(nausea,vomiting,confusion,papilledema)

o Pituitarylesions,TIAs/CVAs;SCI→riskofcomplicationsoffailureandothershit;lowermotorneuronlesions→documentnervedeficitsbeforeusingregionalanaesthesia

• Endocrine:DM,thyroid,phaeochromocytoma,adrenalsuppression,• GI‐Hepatic:hepaticdz,GERD• Renal:disordersoffluid/electrolytebalance,renalfailure• Haematologic:anemias,coagulopathies• Elderly:coexistingdiseaseanddiminishedorganfunction/organreserve• Meds/allergies:needlist!Generallyptscantakeondayofsurgery

o Exceptions;ASA,NSAIDs,insulin,oralhypoglycemics,antidepressants,MAOi• Previousanaesthetics:responsetoprevious;FamHxofmalignanthyperthermiaand

plasmacholinesterasedeficiency• Surgeryproblems:pt’sgeneralmedicalconditionandanticipatedintraoperative

problems• PhysEx:focusonairwayeval,CV,resp,othersystemswithsymptomsofdzfromHx

o General:physicalandmentalstatuso Upperairway:teeth,opening(2fingers),thyromentaldistance(3fingers),

TMJ(1finger)/c‐spinemobility(rememberthe3‐2‐1rule)o Lowerairway:resprate,thoraciccage,auscultation,peripheralsigns

(clubbing,cyanosis)o CV:rate,rhythm,pressure,apicalimpulse,JVP,peripheraledema,S1/2,

murmurs/S3/S4 Assessanatomyforarterialline/centralvenous/intravenousaccess

• Laboratorytesting:o Onlyifindicatedo CBCwheresignifbloodlossanticipated,suspectedhaemdisorder,recent

chemoo Lytesifptonantihypertensivemedications,ordiuretics,chemo,

renal/adrenal/thyroiddisorders

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o ECGforpts>50orHxofcardiacdz,HTN,periphvascdz,DM,renal/thyroid/metabolicdz

o X‐rayfordebilitatingCOPD,asthma,ΔinrespSxinpast6moso Urinalysisforptsw/DM,renaldz,recenturinarytractinfection

1) DefinetheASAphysicalstatusclassification.

I‐HealthyptII‐Mildsystemicdz;nofNallimitationIII‐Severesystemicdz;definitefNallimitationIV‐Severesystemicdz;aconstantthreattolifeV‐Moribundpt;notexpectedtosurvivew/orw/outanoperationfor24hours

2) Howlongshouldelectivesurgerybepostponedfollowingamyocardialinfarction?Whatisthebasisofthisrecommendation?

‐6months,accordingtobothGoldman’sCardiacRiskIndex,andDetsky’sMultifactorialIndex,andthreeothercardiacstudies**Planningtheanaesthetic(5questionstoaskaboutptcondition)1.Isthept’sconditionoptimal?2.Arethereanyprobswhichrequireconsultationorspecialtests?3.Isthereanalternativeprocedurewhichmaybemoreappropriate?4.Whataretheplansforpost‐opmanagementofthept?5.Whatpremedicationifanyisappropriate?

3) Whatinformationshouldbeobtainedintheanaesthetichistory?‐HPI,Meds,Allergies,PMH/SurgHx,pastanaestheticHx,FamHxofanaestheticprobs,functionalinquiry,focusingoncardiorespsystems,NPOstatus,specificquestionsaboutidentifiedproblemlist

4) Whatcommonanaesthetictechniquescanbeusedtoprovideanaesthesiaforlowerabdominalsurgery?(e.g.inguinalherniarepair)

‐general,spinal(avoidintubation→sympatheticstim[↑HR/BP],airwayreflexes[bronchospasm])

5) A)Whatanaestheticrisksmightbeassociatedinapatientwhosmokesregularly?B)Whatinformationobtainedfromhistory,physical,orlaboratoryexaminationmightbeusefulinassessingthisrisk?C)Aretheremeansofdecreasingtherisksofperioperativecomplicationsrelatedtosmoking?

A)airwaysecretions,asthma,COPD,infectionsB)smoker’scough,wheeze,medicationsforbreathing,limitstophysicalactivity/exercisetolerance,chronicinfections,asthma,COPD,CXR,PFTC)“optmizept”Chapter4:Premedication

1) Whyarepatientspremedicatedpriortosurgery?‐pt‐relatedreasons:sedation,amnesia,analgesia,antisialogogueeffect,↓gastricacidity/volume,facilitateanaesthesiainduction

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‐procedure‐relatedreasons:Abxprophylaxis,gastricprophylaxis,corticosteroidcoverage,avoidreflexes(vagal),anticholinergic‐coexistingdiseases:continuept’sownmeds,optimizept’sstatuspriortoprocedure(e.g.bronchodilators,nitroglycerine,β‐blockers,Abx)

2) Whatarethegeneralcontraindicationstotheuseofbenzodiazepineoropioidpremedications?(p.30generalcontraindicationstouseofpremedication)

‐allergyorhypersensitivitytodrug;upperairwaycompromise/respfailure;hemodynamicinstability/shock;decreasedlevelofconsciousnessor↑ICP;severeliver,renal,thyroiddz;obstetricalpts;elderlyordebilitatedptsChapter6:Intubationandanatomyoftheairway

1) Whatisthe“1‐2‐3”test?Usedtoassessseveralfactorsthatmayaffectdecisionsconcerningpt’sairwaymgmt.1)IDanyrestrictedmobilityoftheTMJ‐openmouthwideaspossibleandnotemobilityatmandibularcondyle/TMjoint→spacecreatedb/ttragusofearandmandibularcondyleis~1fingerbreadthinwidth2)Mouthopening:atleast2fingers;noteloose/capped/missingteeth,bridges;withtonguemaximallyprotruded,shouldvisualizepharyngealarches,uvula,softpalate,hardpalate,tonsillarbeds,posteriorpharyngealwall3)Thyromentaldistance‐thyroidnotchtomentum;≥3cmpreferable

2) WhatdoesaclassIhypopharyngealviewmean?WhatstructuresarevisualizedinaclassIhypopharyngealview?

‐adequateexposureoftheglottisduringdirectlaryngoscopyshouldbeeasilyachieved‐canseetongue,hard/softplate,uvula,pharyngealarches,tonsilarbeds,posteriorpharyngealwall

3) WhatstructuresarevisualizedinagradeIIIlaryngealview?‐Onlyepiglottisandaportionofthearytenoids;possiblyahintofthespacebetweenthevocalcords**Trachealintubation

I. PositioningofpatientII. Openingpatient’smouthIII. PerforminglaryngoscopyIV. InsertionoftheETTthroughthevocalcordsandremovingthelaryngoscopeV. Confirmationofcorrectplacement,andsecuringtheETT

4) Whatistheoptimalpositionoftheheadandneckforintubationusingdirect

laryngoscopy?‐headandneckpositionedusingcombinationofbothcervicalflexionandatlanto‐occipitalextension(the“sniffingposition”).Enablesalignmentofaxesofmouth/pharynx/larynx→permitsdirectvisualizationoflarynxduringlaryngoscopy

5) Howistrachealintubationconfirmed?

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‐Immediateabsoluteproof→observingETTpassingthroughvocalcords;observingCO2returningwitheachrespiration;visualizingtracheallumenthroughETTusingafibreopticscope‐Indirectconfirmation→listeningoverepigastriumforabsenceofbreathsoundswithventilation,observingchesttorise/fallw/+pressureventilation,listeningtoapexofeachlungfieldforbreathsoundswithventilation**IFINDOUBT,TAKEITOUTIfunsureoftubeplacement,removeitandresumemaskventilationw/100%O2,stabilizeptandcallforhelp,ratherthanriskhypoxicinjuryandgastricaspiration.**IFINDOUBT,LEAVEITINwhenconsideringextubationafterptwasintubatedforatime,andthereareconcernsaboutsafeextubation,itissafertodelayextubation,continuetosupportventilation,ensuringhemodynamicstability,analgesia,andoxygenation,thanprematurelyextubatingpt.

6) Name4simplemanoeuvresthatcanbeusedtoovercomeanupperairwayobstruction.

‐clearingtheairwayofanyforeignmaterial‐usingachinliftmanoeuvre‐usingajawthrustmanoeuvre‐insertinganoraland/ornasalairway‐positioningtheptontheirsideinthesemi‐pronerecoverypositionChapter7:Intubationdecisions

1) Whatlaboratorycriteriashouldyouusetoassesstheobjectiveneedforintubationandventilation?

• Oxygenationo PaO2<70mmHgwithFiO2=70%o A‐aDO2gradient>350mmHg(normalis≤15mmHg,andincreasesupto37

withincreasingage;PAO2=(Patm–PH2O)xFiO2–PaCO2/0.8• Ventilation

o RR>35/mininadults(muscleswillfatigue)o PaCO2>60innormaladultso PaCO2>45instatusasthmaticus(andrising,despitemaximummedical

mgmt)o RespiratoryacidosiswithpH<7.20inCOPDpts

• Mechanicso VC<15mL/kg(normalvitalcapacity=70mL/kgorapprox.5L;aVCof

15ml/kgisneededtocougheffectivelyandclearsecretionso NIF>‐25cmH2O(normalnegativeinspiratoryforceis~‐80to‐100cmH2O)

2) Whataresomeimportanthistoricalandclinicalfactorsthatsuggesttheneedtointubateandventilateapatient?

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• Realorimpendingairwayobstruction(epiglottitis,thermalburns,mediastinaltumours…)

• Protectionofairway(↓LOC,drugoverdoseetc.)• Trachealbronchialtoilet‐ptswhoareunabletocleartheirsecretions,theETT

providesdirectaccessforsuctioningsecretions(e.g.,COPDw/pneumonia)• Positivepressureventilation‐duringgeneralanaesthesia;otherindicationsforETT

underGAinclude:longprocedure,difficultmaskventilation,operativesitenearpt’sairway,thoraciccavityopened,musclerelaxantsreq’d,andifptindifficultpositiontomaintainmaskanaesthesia

• Clinicalsignsofrespiratoryfailureandfatigue(diaphoresis,tachypnea,tachycardia,accessorymuscleuse,pulsusparadoxus,cyanosis…)

• Shocknotimmediatelyreversedwithmedicaltreatment(i.e.notrespondingtomedicalmgmtinfirst35‐45minutes)

Chapter8:Laryngealmaskairway

1) WhatisthedifferencebetweenaLMAandanendotrachealtube?‐LMA:wideborePVCtubingwithdistalinflatablenon‐latexlaryngealcuff;insertedw/ospecialequipment,inbackofpt’spharynxw/softlaryngealcuffrestingabovevocalcordsatjNoflarynxandesophagus‐ETT:genreq’slaryngoscopeforinsertionintotrachea;passesthroughvocalcordsw/tippositionedinmid‐trachea

2) Whywouldalaryngealmaskairwaybeusedratherthananendotrachealtube?‐pt’swhohavenoID’driskfactorsforaspirationandwhodonotreqintubationandcontrolledventilation‐makebedifficulttoobtainadequatesealw/facemaskinptsw/noteethorfullbeard,soLMAgoodforthosepts‐alsoLMAiseasytoinsert,canbepositionedw/minimalanaestheticdrugs(doesn’treqmusclerelaxants),doesn’tcauseasmuchtraumaandpositioningcomplicationsasETT,doesn’tcauseforeignbodyintracheareflexorlaryngospasm(whenremoved)Chapter9:Rapidsequenceinduction

1) WhatisthepurposeofaRSI?‐usedwhenaptreqGAwhohasbeenID’dashavingriskfactorsforgastricaspiration:↓LOC,trauma,mealw/in6hours,sphincterincompetencesuspected(GERD,hiatushernia,NGtube),↑edabdominalpressure(pregnancy,obesity,bowelobstruction,acuteabdomen)

2) DescribethesequenceofmanoeuvresusedinaRSI.1.SetupIVaccess,cardiacmonitor,oximetry,andpossiblycapnography.2.Planprocedureincorporatingassessmentofphysiologicstatusandairwaydifficulty.3.Prepareequipment,suction,andpotentialrescuedevices.4.Preoxygenate/denitrogenate:ptbreathes100%O2for3‐5minutesorfor4vitalcapacitybreathspriortoinductionofanaesthesia(doNOTbagventilate)5.Considerpretreatmentagentsbasedonunderlyingconditions.*(e.g.Lidocaine,fentanyl,atropine)

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6.Inducewithpotentsedativeagent.7.Giveneuromuscularblockingagentimmediatelyafterinduction.(=fast‐actingmusclerelaxant,e.g.SCh)8.Bag‐maskventilateONLYifhypoxic,considercricoidpressure.(Sellick’smanoeuvre:pressureoncricoidcartilagetocompressesophaguseagainstC6)9.Intubatetracheaaftermusclerelaxationhasbeenachieved.(45‐60saftermusclerelaxantgiven).MustusecuffedETTtopreventaspirationofgastriccontents10.Confirmplacementandsecuretube.11.Providepostintubationsedationandpostintubationmanagement.(ventilatewhenETTinplaceandcuffinflated)

3) Whatisthepurposeofpre‐oxygenation?‐Getridofnitrogenandfloodalveoliw/oxygen,tobuymoretimebeforeaptdesats<90%,ifyoucandoyourshitright;e.g.takes2minutesforahealthypttodesatnormally,buttakes6minutesifyoupreoxygenatefirst

4) Whichpatientsshouldberegardedasbeingatriskofpulmonaryaspirationofgastriccontents?

‐↓LOC(drugoverdose,anaesthesia,headinjury,CNSpathology,traumaorshock)‐impairedairwayreflexes(prolongedtrachealintubation,localanaesthetictoairway,myopathies,CVA,↓LOC‐abnormalanatomy(Zenker’sdiverticulum,esophagealstricture)‐↓GEcompetence(NGtube,elderly,pregnant,hiatushernia,obesity,curare)‐↑intragastricpressure(preggo,obese,bowelobstruction,largeabdotumours,ascites)‐delayedgastricemptying(narcotics,anticholinergics,fear,pain,labour,trauma,preggo,renalfailure,diabetes)

5) Whatmeasurescanbetakentodecreasetheriskofaspiration?‐preopfasting,H2antagonists/antacids(↓acidity),metoclopramide(↓motility),antiemetics,regional/localanaesthesiaratherthanGA,NGtubetoemptystomach,cricoidpressureoninductionofGA,extubationawakeonsideChapter10:monitoringinanaesthesia

1) Whatinformationdoestheanaesthetistusetoassessdepthofanaesthesia?‐GA→lackofresponsetoverbalcommands,lossofblinkreflex(ifinadequate→facialgrimacingtopainfulstimulus,ormovementofarmorleg)‐w/fullparalysisw/musclerelaxants→inadequateanaesthesiashownbyHTN,tachycardia,tearingorsweating‐excessiveanaestheticdepth→cardiacdepression(bradycardia,hypotension),orifexcessivemusclerelaxant→hypoventilationandhypercapnia,hypoxemia

2) Whatinformationcanbeobtainedbymonitoringthecapnograph?‐CapnometryisthemeasurementoftheCO2concentrationduringinspirationandexpiration‐capnogramisthecontinuousdisplayofthe[CO2]waveformsampledfromthept’sairwayduringventilation

• Confirmationoftrachealintubation• Recognitionofaninadvertentesophagealintubation

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• Recogofaninadvertentextubationordisconnection• AssessmentoftheadequacyofventilationandanindirectestimateofPaCO2• Aidsthediagnosisofapulmonaryembolism(airorclot)• Aidstherecogofapartialairwayobstruction(e.g.kinkedETT)• Indirectmeasurementofairwayreactivity(e.g.bronchospasm)• Assessmentoftheeffectofcardiopulmonaryresuscitationefforts3) WhatrelationshipdoestheETCO2valuehavetothePaCO2?• DuringGA,thePaCO2toETCO2gradientistypicallyabout5mmHg(PaCO25mmHg

higher);increasesordecreasesinETCO2valuesmaybetheresultofeitherincreasedCO2productionordecreasedCO2elimination

WhatconditionsmightresultinanETCO2measurementof20mmHgw/aPaCO2measurementof40mmHg?(Seerightcolumn)

↑edETCO2 ↓edETCO2ChangesinCO2production

HyperthermiaSepsis,thyroidstorm

MalignanthyperthermiaMuscularactivity

HypothermiaHypometabolism

ChangesinCO2elimination

HypoventilationRebreathing

HyperventilationHypoperfusionEmbolism

Chapter11:intravenousanaestheticagents

1) Whydoptsawakenfromasleepdoseofthiopentalwithin5to10minutesofitsadministrationwhentheeliminationhalf‐lifeisoftheorderof5‐12hours?

‐b/cthethiopentalhasmovedawayfromthebrainandisenteringthemoreslowlyperfusedorgans,its‘redistribution’fromthebraintoothertissues/organs

2) Whywouldonechoosepropofoloverthiopentalasanintravenousinductionagent?‐ifptallergictothiopental,hasstatusasthmaticusorporphyria,liverdz,myxedema

3) Whenwouldonechooseketamineovereitherthiopentalorpropofolastheintravenousinductiondrug?

‐ketaminepreserveslaryngealandpharyngealairwayreflexes‐producesbothcentralsympatheticstimulationanddirectnegativeionotropiceffectontheheart→↑HR,BP,SVR,pulmartpressure,coronarybloodflow,myocardialoxygenuptake‐∴goodforanaestheticinductioninthesevereasthmaticptortheptwithcardiovascularcollapserequiringemergencysurgery

4) Whataretheconcentrationsandinductiondosesofthiopentalandpropofol?• Thiopental

o Concentration:2.5%(25mg/mL)o Inductiondose:3‐5mg/kg

• Propofolo Concentration:1%(10mg/mL)

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o Inductiondose:2.5‐3.0mg/kgforhealthy,unpremedicatedpt Whenpremedicationgiven,reduceto2.5‐2.0mg/kg Elderly→≤1mg/kg

Chapter12:Musclerelaxants

1) Whatisthedifferencebetweenadepolarizingandnon‐depolarizingmusclerelaxant?Giveexamplesofeach.

‐NON‐depolarizingneuromuscularblockingagents• CompetewithAChforthecholinergicnicotinicreceptor• As[]ofmusclerelaxant↑attheNMJ,theintensityofmuscleparalysis↑• Anticholinesteraseagents(neostigmine,edrophonium)inhibitthebreakdownof

ACh→↑ACh[]attheNMJ→competitivelyreversetheeffectsofanon‐depolarizingneuromuscularblockade

‐Depolarizingneuromuscularblockingagents• Succinylcholine(SCh)ismostfrequentlymusedmusclerelaxantusedbynon‐

anaesthetists,andistheonlydrugofthisclassthatisclinicallyused• Depolarizingmusclerelaxantsbindanddepolarizetheend‐platecholinergic

receptors• Theinitialdepolarizationcanbeobservedasirregular,generalizedfasciculations

occurringintheskeletalmuscles2) WhataretheabsolutecontraindicationstotheuseofSCh?• Inabilitytomaintainanairway• Lackofresuscitativeequipment• Knownhypersensitivityorallergy• Positivehistoryofmalignanthyperthermia• Myotonia(M.Congenita,M.Dystrophyica…)• PtsID’dasbeingatriskofahyperkalemicresponsetoSCh3) Whichpt’saresusceptibletohyperkalemiafollowingSCh?• CholinergicreceptorslocatedonskeletalmusclemembranesoutsideofNMJcanbe

dramaticallyincreasedinnumberovera24hrperiodwhenevernerveimpulseactivitytothemuscleisinterrupted

• Ptswhohavesustained3rd‐degreeburnsortraumaticparalysis,neuromusculardiseaseslikemusculardystrophy,severeintra‐abdominalinfections,severeclosedheadinjury,UMNlesions,ptsinrenalfailure

• GivingSCh→abnormallyhighfluxofK(dueto↑edreceptors)→acuteriseinpotassiumtolevelsashighas13meq/L→suddencardiacarrest

4) WhatistheconcentrationatwhichSChissupplied?Whatisthedoseforintubation?‐Formulatedat20mg/mL‐Intubationdose:(withcurarepretreatment)1.5‐2mg/kgIV→NOTE:Initialdoseofsuccinylcholinemustbeincreasedwhennondepolarizingagentpretreatmentusedbecauseoftheantagonismbetweensuccinylcholineandnondepolarizingneuromuscular‐blockingagents. ‐withoutcurarepretreatment→1.1.5mg/kgIV

5) Whichdrugscanbeusedtoantagonizeaneuromuscularblock?

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• Musclerelaxationproducedbynon‐depolarizingneuromuscularagentsmaybereversedbyanticholinesteraseagentslikeedrophonium,neostigmine

o PreventbreakdownofAChinNMJ→competeswithdrugtoallowreceptortobecomeresponsivetoreleaseofAChfromnerves

o The↑ed[]sofAChalsostimulatethemuscariniccholinergicreceptors,resultinginbradycardia,salivation,andincreasedbowelperistalsis

o Anti‐cholinergicagentssuchasatropineandglycopyrrolateareadministeredpriortoreversal,toblocktheseunwantedmuscariniceffects

Chapter13:Inhalationalanaestheticagents

1) WhatisMAC?‐SimilartoED50,theminimumalveolarconcentrationisthealveolarconcentrationinoxygenatoneatmospherethatwillprevent50%ofthesubjectsfrommakingapurposefulmovementinresponsetoapainfulstimulussuchasasurgicalincision‐itisnecessarytoestablishananaestheticdepthequivalentto1.2to1.3oftheMACvaluetopreventmovementin95%ofpts

2) Whatistherelationshipbetweentheanaestheticconcentrationthatissetontheanaestheticvaporizerandtheanaestheticconcentrationinthept’sbrain?

‐theanaesthetictensioncascadeovertime‐thedelivered[]tendstobe>inspired>alveolar>brain‐increasingeitherthefreshgasflowrateoranaestheticconcentrationwillresultinafasterdeliveryoftheinhaledanaestheticagenttothebrain(duetoafasterriseinthealveolarconcentration)‐amountofalveolarventilation(VA=respratextidalvolume)‐intermsofalveoli→braintime,thiswillbefasterwith: ‐rateofbloodflowtobrain ‐solubilityoftheinhalationalagentinthebrain ‐differenceinthearterialandvenous[]softheinhalationalagent

3) Whatisdiffusionhypoxia?‐mayresultatendofanaesthetic‐asnitrousoxideisdiscontinued,thebodystoresofitarereleasedandfloodthealveoli,dilutingtheO2presentinthealveoli‐whenonlyroomairisadministeredattheendoftheanaesthetic,thedilutionofO2maybesufficienttocreateahypoxicmixture,andresultinhypoxemia‐othercausesofhypoxemiaincludeanaestheticagents,neuromuscularblockade,painwithsplintedrespirations‐∴administer100%O2attheendofananaesthetictoavoidthis

4) WhataretheMACvaluesofisoflurane,enfluraneandhalothaneinoxygen?Isoflurane:1.16%Enflurane:1.68%Halothane:0.75%Desflurane:6%Sevoflurane:2%

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Chapter14:Narcoticagonistsandantagonists

1) Whatundesirableeffectsdoopioidshave?‐maycausedysphoricrxnswhenadministeredtoptswhoarenotexperiencingpain‐nausea,emesis‐respdepression(↓rate,minuteventilation;↑tidalvolume)→slow,deepbreatihing‐vasodilation→↓BP/SVR,bradycardia‐slowGImotility→constipation/postopileus;↑biliarytracttone→pptbiliarycolic;↑urinarybladdersphinctertone→postopurinaryretention‐anaphylaxis,bronchospasm,chestwallrigidity,pruritis

2) Nameanopioidantagonist.Whatdoseofthisdrugwouldbeappropriatetoreverseopioidinducedrespiratorydepression?What,ifany,areanypotentialproblemsofgivingtoomuchofthisantagonist?

• Naloxone(Narcan)• Givesmallincrementaldosesof40mcg• Suddenreversaloftheanalgesiceffectsofopioidsmayresultifhighdosesof

naloxonearegiven→abruptreturnofpaincanresultinHTN,tachycardia,pulmedema,ventriculardysrhythmiasandcardiacarrest

• Continuousinfusionsof3‐10mcg/kg/hrcanbeusedifsedationorrespdepressionrecur

Chapter15:Localandregionalanaesthesia

1) Name2classesoflocalanaestheticagents,angiveexamplesofeachAmides:lidocaine(maxdose4mg/kg,7withepi),bupivicane(2.5mg/kg,3withepi)Esters:chlorprocaine(11mg/kg,14withepi)

2) WhatisPABA,andwhatroledoesithaveinlocalanaesthesia?• Para‐aminobenzoicacid,usedasapreservativeinlocalanaestheticsolutions,and

mayincreaseaLA’spotentialneuro‐andmyo‐toxicities3) Name4techniquesofadministeringalocalanaestheticdrug.• Topical,infiltrative,intravenousregional,peripheralneuralblockade,centralneural

blockade4) Whyisavasoconstrictoroftenusedwithalocalanaesthetic?Giveanexampleofa

LAvasoconstrictoranditsconcentration.Whenwouldtheuseofavasoconstrictorbecontraindicated?

• Vasoconstrictor(e.g.epinephrine,phenylephrine)usedtoretardvascularabsorptiontoreducesystemicsideeffectsofLA

• Epinephrine[]stypically1:100000to1:200000o 1:200000has5mcg/mLofepinephrine

• Vasoconstrictorscontraindicatedinfingers,toesandpenis5) Whichregionalblockresultsinthehighest[]oflocalanaestheticintheblood?

‐intercostalnerveblocksresultinthehighestpeaklocalanaestheticbloodconcentrations6) Whatisthemaxrecommendeddoesofplainlidocaine,andoflidocainewitha

vasoconstrictor?‐4mg/kg;withepi→7mg/kg

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7) Whymightaregionalanaestheticbegivenaswellasageneralanaesthetic?‐forpost‐oppainmgmt

8) Describesomeofthesignsandsymptomsoflocalanaesthetictoxicity.‐neurotoxicity→immediateandseverepain→pathologicdamagetonerve‐myotoxicity→histologicalchangesinthetissues,buttransientandreversible

9) Describethestepsintreatinganacutelocalanaesthetictoxicity.‐ensureclearairway(suction,chinlift/jawthrust,airways,positioninginlatdecub)‐ensureadequateventilation(bag/mask,avoidhypoventilation→↑LAuptake,considerintubation)‐providesupplementalO2(8‐10L/minforambubagoxflow)‐AssesstheHRandrhythm,applymonitors(treatbradyw/atropine;useepiforprofoundCVcollapse;considerearlyelectricalcardioversionforarrhythmias)‐AssesstheBPandperfusion‐determineresponsiveness(ifpthypotensive→Trendelenburgposition;administerbolusofringer’slactate;supportBPw/ephedrineorphenylephrine)‐stopseizures(protectptfrominjuryduringseizure;considerdiazepamorsodiumthiopentaltostopseizure)

10) Whatisthedifferenceb/taspinalandanepiduralanaesthetic?‐botharecentralneuralblockade‐epiduralanaesthesiaisinjectingdrugsintotheepiduralspace(b/tligamentumflavumandduramater,exteriortospinalfluid);drugmustpassthroughmyelinsheathscoveringthenerveroots ‐duraactsasbarriertoepiduralLAmovingintotheCSFspace ‐sloweronsetb/cnervesareinsulated;produceslessintenseblock ‐req5‐10timestheamountofLAthatwouldbeusedforspinalanaesthesia‐spinalanaesthesiainvolvespassinganeedlethroughepiduralspace,throughduraandintotheCSFspace‐thesubarachnoidspace,directlyincontactwiththebarenerveroots ‐drugsproduceaveryrapidandintensenerveblock

11) Howmanymilligramsoflidocainearein20mLofa2%solution?400mgChapter16:Acutepainmanagement

1) Listthephysiologicaleffectsofacutepain.• E.g.chest/abdoincisionw/outpainmgmt→musclesplinting,Ø

coughing→atelectasisandpneumonia• Barrageofnociceptivestimuli→↑sympathetictone→HTN,tachycardia,

↑contractility/worko Ifinsettingof↓O2supply→myocardialischemia,CHF,MI

• ↑symptonealso→↑intestinalsecretions,slowsgutmotility,↑smoothmuscletone→gastricstasisw/nausea,emesis,ileus,urinaryretention

• pain→stressresponse→hypercoagulablestate→PE,MIo also→↓immunocompetence,hypermetabolism,mobilizationofenergy

stores→hyperglycemia,largenetproteinlosses→delayedwoundhealing

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2) ContrastintramuscularandPCAopioidadministration• IntermittentIMadministration→widefluctuationsinserumopioidconcentrations

→periodsofover‐sedationalternatingwithperiodsofpoorpaincontrol• IVPCAopioidadministration→rapidlyadjustedbypt→analgesic[]sofopioidsin

serummaintainedforlongperiodsoftime3) Whataretheadverseeffectsresultingfromtheadministrationofexcessiveopioid

analgesics?• Sedation,respiratorydepression,pruritis,↑edincidenceofnausea/vomiting4) Whatnon‐opioidanalgesicagentsareavailableforthecontrolofacutepain?• Aspirin,ibuprofen,indomethacin,naproxen,ketorolac(toradol),[gabapentin,

acetaminophen)5) Whatarethecontraindicationstoadministeringanon‐steroidalanti‐inflammatory

drug?• AllergytoASAorotherNSAID;relativecontraindicationwhenthereisahxof

asthma,nasalpolypsorangioedema• Renalinsufficiency,CHF,pepticulcerdz,activeIBD,pregnancy/lactation,bleeding

disorders6) ListanappropriatedoseandschedulefortwocommonNSAIDsusedtocontrol

acutepain.• Ibuprofen400‐800mgPOq6‐8h• Ketorolac10mgPOq4‐6h,maxpo40mg/day

o 10‐30mgIMq4‐6h,maxIM120mg/dayChapter17:Chronicpain

1) Whatisthedifferenceb/tacuteandchronicpain?• Acutepainisthenociceptionduetotissueinjuryandreleaseofnociceptiveagents• Chronicpainisan“unpleasantsensoryandemotionalexperienceassociatedwith

actualorpotentialtissuedamage,ordescribedintermsofsuchdamage”o So,doesn’tactuallyrequirepresenceoftissuedmg,andtendstolastwell

beyondthehealingperiodoftissueinjury2) WhatisRSD?WhatconditionsmayleadtothedevelopmentofRSD?• ReflexSympatheticDystrophy

o Varietyofconditionsincludingminorcausalgia,posttraumaticpainsyndrome,Sudeck’satrophy,shoulderhandsyndrome

• Pptfactorsincludeaccidental/surgicaltrauma,diseasestates• Characterizedbypain,vasomotorchanges,autonomicdisturbances,delayed

recoveryoffN,trophicchanges• Commonoutcomeoforthopaedicinjuriesandindustrialaccidents(butno

correlationb/tseverityofinjuryanddevelopmentofRSD;mustbepromptlyrecog’dandtreated

3) WhatmodalitiesarecommonlyusedtotreatRSD?• Earlytxwithsympatheticinterruptionresultsinpainreliefandreversesthe

pathophysiologicalabnormalities

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o Treatoriginalinjuriesproperlyandrapidly(removeforeignbodies,immobilize,repairshit,relievepain)

o Txmodalitiesincludeearlyuseofsympatheticblocks,physio,psychotherapy,medicaltherapyandifthesefail,surgicalsympathectomy

4) HowisadxofRSDmade?• Criteriaare

o Hxofrecentorremoteaccidentaloriatrogenictraumaordzo Ptcomplainsofpersistentpainthatisburning,achingorthrobbingo Oneormoreof:

Vasomotor/sudomotorchanges Trophicchanges,edema,hypersensitivitytocold Muscleweaknessoratrophy

o ReliefofSxobtainedafterregionalsympatheticblockade5) Whataretriggerpoints?• Inmyofascialpainsyndrome,triggerpointsarehypersensitivepointsproducing

pain,musclespasm,tenderness,stiffness,andweakness• Inaffectedareas,tautmusclebandsmaybepalpable,arecalledTPs

o Painfromtheseisdescribedassteady,deepandaching,andmaybeexacerbatedbystretch,cold,stress,fatigue,viralillnessesordirectpressure

6) Name2surgicalconditionsthatmaypresentw/backpainandrequireemergencysurgicalintervention.

• CaudaEquinaSyndromeo Discherniation,tumourmass,abscesso Signs:neurodeficitinlowerextremities(paralysis,lossofsensation),lossof

bowelorbladdercontinence,weakness,depressedreflexes,saddleanaesthesia

• Aorticaneurysmo Leaking,dissecting,ruptured

Chapter18:Obstetricalanaesthesia

1) Whatissupinehypotensivesyndrome?Howcanitbeprevented?• WhenthegraviduteruscompressestheIVCand/oraortawhentheparturientliesin

thesupineposition(about15%ofptsasearlyas20tweek,↑freqin3rdtrimester)• IVCcompressioncauses↓venousreturntoheart→signsofshock:hypotension,

pallor,sweating,nausea/vomiting,Δsinmentationo ↑venouspressureinlowerextremitiesanduterus∴↓uterinebloodflow

• aortacompression→arterialhypotensioninuterus→↓uterinebloodflow→fetaldistress/asphyxia

• Prevention:avoidsupineposition;liesonside;judicioususeoflumbarregionalanaesthetics,whichcanexaggeratehypotensiveeffects

2) Whatfactorsmayinfluenceapt’sexperienceofpainduringlabouranddelivery?

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• Psychologicalstate,mentalpreparation,familysupport,medicalsupport,culturalbackground,primivsmultipara,sizeandpresentationoffetus,sizeandanatomyofpelvis,useofmedicationstoaugmentlabour(e.g.oxytocin),durationoflabour

3) Whatoptionsareavailablefordealingwiththepainoflabouranddelivery?• Nothing,psychologicalsupport(coaches,partner,familymembers),behavioural

modification(psychoprophylaxis‐Lamaze),hypnotherapy,education(expectations,classes),massage,walking,sedatives,opioidanalgesics(+/‐antiemetics),epiduralanalgesia,spinalanaesthesia,generalanaesthesia

4) Whatarethemajorrisksofgeneralanaesthesiaintheparturientundergoingacaesareansection?

• AllparturientsconsideredtohavefullstomachandgastricprecautionsincludingRSIareindicatedwithGA

• Upperairwayedemaoccursinpregnancy;allparturientsconsideredtohavepotentiallydifficultairwaytointubate

• GAintroducesrisksoffailedintubation,andriskofhypoxemiaand/orpulmonaryaspirationofgastricacid

• GAcreatespotentialofhavingmaternaldrugstransferredtoneonate→neonataldepressionandneedforresuscitation

Chapter19:Basicneonatalresuscitation

1) WhatistheApgarscoreofababythatislimp,blue,hasnoresponsetooropharyngealsuctioning,aheartrateof60bpm,andirregulargaspingrespiratoryefforts?

• APGAR:Appearance(colour),Pulse(HR),Grimace(reflexirritability),Activity(Muscletone),Respiration

• Muscletone‐0,Colour‐0,Reflexirritability‐0,HR<100‐1,Respiration‐1=22) Describethebasicstepsinneonatalresuscitation.• Opentheairway

o Positioning,suctionmouththennose,monitorheartrateforbradycardia,considerspecialendotrachealsuctioningindepressedinfant.

• Keeptheinfantwarmanddryo Overheadradiantheater,drytheinfant;thegentlestimulationwillalsohelp

initiateandmaintainbreathing• Physicalstimulation

o Ifdrying/suctioningdonotinduceeffectivebreathing→gentleslapping/flickingofsolesoffeet,orrubbinginfant’sbackmaybeuseful

o Donotwastetimecontinuingtactilestimifnoresponseafter10‐15s• Evaluatetheinfant

o Respirations:apneicorgaspinginfants(despitebriefstim)shouldreceivepositivepressureventilation(PPV)

o Heartrate:monitorbyauscultationorpalpation;if<100bpm,beginPPV,evenifinfantmakingsomerespiratoryefforts

o Colour:presenceofcentralcyanosismeansinfantnotwelloxygenated;providefacemaskw/O2at5L/minuntilinfantbecomespink

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3) Whenispositivepressureventilation(PPV)indicatedinthenewborninfant?DescribethetechniqueofPPV.

• Ventilatorysupportrequiredwhenapneaorgaspingrespirationsarepresent,theHRis<100bpm,orcentralcyanosispersistsdespite100%O2

• Mostneonatescanbeadequatelyventilatedw/abag‐masko Theassistedventilatoryrateshouldbeb/t40‐60breathsperminuteo Initiallunginflationpressuresmaybeashighas30‐40cmH2Otoovercome

theelasticforcesofthelungsiftheinfanthasnottakeitsfirstbreatho Subsequentventilationshouldbeachievedwithairwaypressuresof15‐20

cmH2O**Adequateventilationisassessedby:‐Observingchestwallmotionandhearingbreathsoundsbilaterally**WhenshouldIstartchestcompressions?‐whenHRremains<80bpmdespitePPVwith100%O2‐chestcompressionscanbediscontinuedwhentheHRis≥80bpm**Whatisthepropertechniqueforadministeringchestcompressionstoaninfant?

• 2methodso thumbmethod:fingersaroundback,thumbssidebysideoversternum,with

downwarddisplacementofsternumo Twofingerapproach:middleandringfingersofonehandperpendicularto

chestasfingertipsapplypressuretosternum;otherhandsupportsbackbelow

o Pressureenoughtoachieve1.5cmofdisplacemento 120compressionsperminute(2/sec)

**The4commondrugsusedinresuscitationofthedepressedneonate:

1. Oxygen2. Intravenousfluids3. Epinephrine4. Naloxone

4) Assuminganewborninfantweighs3kg,whatisthe[]anddoseofepinephrine,and

howoughtitbeadministered?• Epinephrine[]inneonateresuscitationissuppliedas0.1mg/mLdilution• IVdoseis0.01to0.03mg/kg• Ina3kginfant,0.25mLto0.75mLofepinephrinewouldbeanappropriatestarting

dose• IfIVrouteunavailable,epicanbegiventhroughETT

o Shouldbedilutedw/1‐2mLofsalineo IfinfantdoesnotrespondtoinitialETTdose,increasebyafactorof10(0.1‐

0.2mg/kg)

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Chapter20:Intravenousfluidandbloodcomponenttherapy

1) Howarethehourlyanddailymaintenancefluidrequirementscalculated?Maintenancewaterrequirements

Perhour Perday1stto10thkg 4ml/kg 100ml/kg11thto20thkg 2ml/kg 50ml/kg21sttonthkg 1ml/kg 20ml/kg

2) Listconditionsthatmaybeassociatedwithasignificantpreoperativefluiddeficit.• Fracturedhip,femur,pelvis;bowelobstruction;preoperativebowelprep;trauma;

protractedvomitinganddiarrhea;burns;sepsis;pancreatitis3) Whatisthedifferenceb/tacrystalloidandacolloid?Giveexamplesofeach.• Crystalloidsolutionsaresaltcontainingsolutionsthataresemipermeabletocellular

membraneso E.g.NS,RL,“2/3,1/3”IVsolutions

• ColloidIVsolutionscontainaggregatesofmoleculesthatresistdiffusionacrosscellularmembranes

o Maybesynthetic,e.g.pentaspan,hetaspan(?sp),dextrano Maybecollectedfromdonorbloodpool,e.g.albumen,plasma,wholeblood

4) Whichptsshouldconsiderautologousblooddonation?Forwhichpatientsisthisnotsuitable?

• Preopcollectionofbloodfromaptwhoisscheduledtohavesurgery,andforwhomoneanticipatestheneedforaperioperativebloodtransfusion

• Notsuitableforptsw/bacterialorviralinfections,ptswithHb<110g/Landptswithunstableanginaorcriticalaorticstenosis

5) Calculatetheacceptableamountofbloodthatcanbelostin70kgmaleifhisinitialhemoglobinis140g/dL,andtheacceptedminimalhemoglobinaftersurgeryis80g/dL.

• ABL=(Hbi‐Hbf)/HbixEBVo =(140‐80)/140x(70ml/kgx70kg=4900ml)=2100mL

6) WhatisthemostcommoncauseofanABOincompatiblebloodtransfusion?‐clericalerrorinpatientandbloodidentification

7) Name3differentbloodcomponentsthatmaybetransfused.• Wholeblood:autologous• Freshfrozenplasma:indicatedtoreplacecertainfactordeficiencies• Platelets:aftermassivetransfusion,associatedwithabnormalbleedingand

dilutionalthrombocytopenia**Potentialcomplicationsofbloodtransfusions

• Air(embolism)• Volume(circulatoryoverload)• Cold(hypothermia)• RBCs(major/minorreactions)• WBCs(febrilereaction)

• Plasma(Allergicrxn,dilutionalcoagulopathy)

• Platelets(dilutionalcoagulopathy)• Biochem.(citratetoxicity,

hyperkalemia,hypoCa)

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• Microaggreg.(Dyspnea)• Infections(bacterial,viral,

parasitic)

• Immune(immunesuppression)

Chapter21:Commonperioperativeproblems**Severebradycardiamustbeassumedtobesecondarytohypoxemiauntilprovenotherwise

1) Defineshock.Classifythedifferenttypesofshockandgiveexamplesofeach.Shock(Tintinalli’s)Type CommentHypovolemicCausedbyinadequatecirculatingvolumeCardiogenic CausedbyinadequatecardiacpumpfunctionObstructive CausedbyextracardiacobstructiontobloodflowDistributive Metabolicderangementsthatimpaircellularrespirationsuchascyanide

toxicity,sepsis.• Hypovolemicshock‐themostcommontypeofshock,withlowcentralvenous

pressureandlowpulmonarycapillarywedgepressure• Distributiveshockischaracterizedbysystemicvasodilation,relativehypovolemia,

andanincreaseincardiacoutputo Mostcommonformofthistypeissepticshock,whereateriovenousshunting

atthetissuelevelresultsinanaccumulationoflacticacidandtissueanoxia• Cardiogenicshockwhenheartfailstoperformitspumpingfunction,asaresultofa

myocardial,valvularorelectricalproblemo Myocardialinfarctionisthemostcommoncause,wherecharacteristic

findingsincludeanincreaseinCVP,PCWPandSVR• Obstructiveshockoccurswhenthereisanobstructionpreventingcardiacfillingor

emptyingo Twoimmediatelytreatablecausesofitincludeatensionpneumothoraxand

cardiactamponade**Nauseaandvomitingperioperativelymustbeassumedtobesecondarytobradycardiaandhypotensionuntilprovenotherwise

2) Whataresometreatablecausesofanagitatedpostopstate?• Upperairwayobstruction,residualparalysis,hypercarbia,andhypoxemiaareall

potentstimulantswhichcanproduceanagitatedstate• Commoncausesofagitationinelderlyptsarepainandbladderorboweldistension• Excessivesedationcanbetreatedwithreversingagents,dependingonthecause

Chapter22:Managingthecirculation

1) Whatarethebroadgoalsincontrollingthecirculation?• Theprinciplegoalofcirculatorysupportistooptimizetissueperfusionwith

oxygenatedblood

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o Toachievethis,onemustassessandoptimizethepreload,afterload,heartrate,contractility,oxygentransportandorganperfusion

2) Whatarethedifferencesb/tanalpha‐1andbeta‐1adrenergicagonist?Giveexamplesofeach.

• Alpha‐1,e.g.phenylephrineo Vasoconstrictionoftheskin,gut,kidney,liverandheart

• Beta‐1,e.g.isoproterenolo Increasedheartrate,myocardialconductionandcontractility

3) Whatarethefactorswhichdeterminecardiacoutput?• CO=HRxSV• Thedeterminantsofcardiacoutputarepreload(theend‐diastolicstretchoftheleft

ventricle),theheartrate,thecontractility(themyocardium’sintrinsicabilitytoperformworkatanygivenlevelofend‐diastolicfibrelength[preload]),andtheafterload(themyocardialwallstressoftheleftventricleduringejection)

Chapter23;Oxygentherapyandhypoxia

1) Listsomedevicesthatarecommonlyusedtodeliveroxygentospontaneouslybreathingpatients.

• Nasalprongs,simplefacemaskoxygen,Venturifacemask,non‐rebreathingfacemaskwithreservoirbag

2) Whenshouldapuritanfacemaskbeused?Whenshouldoneuseamanualresuscitationdevice,suchasanambubagandmaskunit?

• Thepuritanmaskdeliversthehighestlevelofhumidifiedoxygeno Oxygenflowratesof>30L/mincanbeachieved,ensuringaconsistent

inspiredoxygenconcentrationo Shoulduseadoubleflowsetuporanon‐rebreathingfacemaskw/reservoir

bagwhen>50%inspiredO2[]isrequired• Theambubagandmaskunitisusedforprovidingprimaryairwaymgmtinpts

requiringpositivepressureventilationandoxygenationo Canbeusedastheprimarysystemforairwaymgmtintheptrequiring

ventilatorysupport3) Listthefivecategoriesofconditionscausinghypoxemia.

Hypoxemia:lowlevelofO2intheblood• DecreasedFiO2

o ↓edinspiredO2concentrationor↓edbarometricpressure(altitude)• Decreasedalveolarventilation

o Hypoventilation(2°tosedativedrugsorpainiscommon)• Increaseddeadspaceventilation(ventilation‐perfusioninequality)

o RespondstosupplementalO2therapyo CausesincludehypovolemiaandhighairwaypressureswithPPVo Pulmonaryembolism,emphysema,bronchitis

• Increasedshunto Perfusionofalveoliwithoutventilation,e.g.atelectasis,aspiration,CHF,

pneumoniaandendobronchialintubationwithlobarcollapse

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• Decreaseddiffusiono Highaltitude,anemia,severeexerciseo Pulmonaryfibrosis,emphysema,interstitialpulmonarypathology(e.g.

sarcoidosis)4) Listthefourcategoriesofconditionscausinghypoxia.

Hypoxia:lowlevelofO2intheair,blood,ortissues• Decreasedfunctionalhemoglobin

o Anemia,hemoglobinopathies• DecreasedPaO2

o Hypoxemia• Decreasedtissueperfusion

o Shockstates(hypovolemic,cardiogenic,distributive,obstructive)• Cellularhypoxia

o Histotoxicpoisoning(e.g.cyanide)Chapter24:Unusualanaestheticcomplications

1) WhatisMH?• ArareclinicalsyndromethathasbeenobservedduringGA

o Acutefulminantform,triggeredbycertainanaestheticdrugs→hypermetabolicstateduetoacuteuncontrolledskeletalmusclemetabolism

o RapidincreasesinO2consumption,carbondioxideproductionandheatresultindesaturationorcyanosis,elevatedend‐tidalCO2valuesandrapidincreasesintemperature

2) List2anaestheticagentsthatmaytriggeranMHreaction.• SCh(depolarizingmusclerelaxant)andanyofthevolatileanaestheticagents

(isoflurane,halothane,enflurane,sevoflurane)3) WhichdrugisusedspecificallytotreatanMHreaction?• Dantrolene‐skeletalmusclerelaxant(everyhospitalthatprovidesGAservicesis

req’dtokeepacurrentstock[minimum36vials]ofdantroleneavailableintheirpharmacydepartment)

4) Whatstrategiesareusefulinreducingtheperioperativeriskofpulmonaryaspirationofgastriccontents?

• Avoidimpairingairwayreflexes(chooselocalorregionalanaesthetic)• Reducegastricvolumeandacidity

o Fasting,gastricmotilityagents,H2blockers,antacids(sodiumcitrate),gastricemptyingbyNGtube

• Inptswithanticipateddifficultintubation,topicalizationandlocalanaestheticblocksoftheupperairwayreduceschanceoffailedintubation,difficultmaskventilationandsubsequentgastricaspiration

• Ptsw/ID’driskfactorsforgastricaspirationwhorequireGAmusthaveRSI(seeabove)

5) Describethestepsusedtotreatananaphylacticreaction.• TheABCsforanaphylaxis:

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o Airway,andadrenalineo Breathing,andBenadrylo Cyrstalloidsandcimetidineo Steroids

• Mgmtofanaphylaxisduringanaesthesiao Stopdrugorallergenadministrationo Provide100%O2o Discontinuesurgeryandanaesthesiaassoonasfeasibleo Giveepi50‐100mcgIVwithhypotension,0.5‐1.0mgIVwithCVcollapseo Epiinfusion0.05‐0.2mcg/kg/mino Crystalloids(NS,RL)IV,mayreq2‐4Lfora70kgadult,i.e.25‐50ml/kgo Diphenhydramine50mgivo Cimetidine300mgIV,orranitidine50mgIVo Hydrocortisone100mgIV,ormethylprednisolone1mg/kgIVq6hx24ho Inhaledsalbutamolforbronchospasmo Avoidbetablockers