preoperative medications goals of pre-op medication

Preoperative MedicationsPreoperative Medications

Goals of Pre-op MedicationGoals of Pre-op Medication Optimize physical conditionOptimize physical condition Relief of anxietyRelief of anxiety Relief of painRelief of pain AmnesiaAmnesia Facilitate induction Facilitate induction

Goals (con’t)Goals (con’t) Facilitate smooth operative Facilitate smooth operative

coursecourse Facilitate smooth wake-upFacilitate smooth wake-up Antiemetic effectAntiemetic effect Prophylaxis against aspirationProphylaxis against aspiration

Psychological PreparationPsychological Preparation Pre-op visit lays the foundationPre-op visit lays the foundation– Trust and confidence are Trust and confidence are

essentialessential– Be efficient, informative and Be efficient, informative and

reassuringreassuring– More effective than sedativesMore effective than sedatives

Psychological Prep (con’t)Psychological Prep (con’t) All patients have some anxietyAll patients have some anxiety– May be outwardly calm, inwardly May be outwardly calm, inwardly

terrified terrified Patients on sedatives have Patients on sedatives have

more anxietymore anxiety

Preoperative MedicationPreoperative Medication

Should be individualized Should be individualized

Give for specific indicationsGive for specific indications

Monitoring should be Monitoring should be

appropriateappropriate

Contraindications to SedationContraindications to Sedation

Poor physiologic reservePoor physiologic reserve

Extremes of ageExtremes of age

Head injuryHead injury

HypovolemiaHypovolemia

Routes of AdministrationRoutes of Administration Oral (60-90 minutes)Oral (60-90 minutes) Intramuscular (30-60 minutes)Intramuscular (30-60 minutes) IntravenousIntravenous RectalRectal NasalNasal DermalDermal

Specific Drugs and DosagesSpecific Drugs and Dosages

Know drugs in each classKnow drugs in each class

Know characteristics of classKnow characteristics of class

BenzodiazepinesBenzodiazepines AnxiolysisAnxiolysis AmnesiaAmnesia SedationSedation Anti-convulsantAnti-convulsant All effects are dose-dependentAll effects are dose-dependent

BenzodiazepinesBenzodiazepines Minimal respiratory depressionMinimal respiratory depression Minimal cardiovascular Minimal cardiovascular

depressiondepression Work well with opioidsWork well with opioids Few side effectsFew side effects

CNS ActionCNS Action SedationSedation

– Enhancement of GABAEnhancement of GABA AnxiolyticAnxiolytic

– Glycine mediated inhibition of brain Glycine mediated inhibition of brain stemstem

AmnesiaAmnesia– Unknown mechanismUnknown mechanism

Specific BenzodiazepinesSpecific Benzodiazepines Diazepam (standard)Diazepam (standard)– Pain on injectionPain on injection– Active metabolitesActive metabolites– Good anticonvulsantGood anticonvulsant– Used as P.O.. pre-opUsed as P.O.. pre-op

Specific Benzodiazepines (con’t)Specific Benzodiazepines (con’t)

LorazepamLorazepam

– Slow onset, long durationSlow onset, long duration

– ProfoundProfound amnesia amnesia

– Not good for outpatientsNot good for outpatients

Specific Benzodiazepines (con’t)Specific Benzodiazepines (con’t)

MidazolamMidazolam– No irritation or phlebitisNo irritation or phlebitis– 2-3x potent as diazepam2-3x potent as diazepam– Rapid onset, rapid metabolismRapid onset, rapid metabolism– Excellent short-term amnesiaExcellent short-term amnesia– Given IV prior to surgeryGiven IV prior to surgery– Given P.O.. to childrenGiven P.O.. to children

BarbituratesBarbiturates SedativeSedative Dose dependent respiratory Dose dependent respiratory

depressiondepression Less safe than benzodiazepinesLess safe than benzodiazepines Do notDo not give to patients with give to patients with

porphyriaporphyria

Butyrophenones (Droperidol)Butyrophenones (Droperidol) Dopamine antagonistDopamine antagonist Appear calm and tranquilAppear calm and tranquil

– Inner terror is reportedInner terror is reported– High rate for refusing surgeryHigh rate for refusing surgery

Alpha blockadeAlpha blockade Excellent anti-emeticExcellent anti-emetic

Other SedativesOther Sedatives HydroxyzineHydroxyzine– Used to augment opioidsUsed to augment opioids

DiphenhydramineDiphenhydramine– Histamine blockerHistamine blocker– Sedative and anticholiergicSedative and anticholiergic

Other Sedatives (con’t)Other Sedatives (con’t)

PhenothiazinesPhenothiazines

– Used to augment opioidsUsed to augment opioids

Chloral hydrateChloral hydrate

– P.O.. pre-op for elderly patientsP.O.. pre-op for elderly patients

OpioidsOpioids Produce analgesiaProduce analgesia Useful prior to painful procedureUseful prior to painful procedure Establish baseline analgesiaEstablish baseline analgesia Reduce anesthetic requirementsReduce anesthetic requirements Comfort upon awakeningComfort upon awakening Work well with sedativesWork well with sedatives

Problems with OpioidsProblems with Opioids

Respiratory depressionRespiratory depression

Orthostatic hypertensionOrthostatic hypertension

Histamine release (morphine)Histamine release (morphine)

Shift in COShift in CO2 2 response curve response curve

Problems with Opioids (con’t)Problems with Opioids (con’t)

Occasional dysphoriaOccasional dysphoria

Nausea and vomitingNausea and vomiting

PruritusPruritus

Sphincter of Oddi spasmSphincter of Oddi spasm

Opioid PremedicationOpioid Premedication Usually given IV in holding Usually given IV in holding

areaarea– Monitor pulse oximetryMonitor pulse oximetry

Fentanyl lollipopFentanyl lollipop Nasal sufentanilNasal sufentanil Oral codeineOral codeine

Prophylaxis for AspirationProphylaxis for Aspiration

Who is at risk?Who is at risk? Full stomach (all emergencies)Full stomach (all emergencies) PregnancyPregnancy ObesityObesity DiabetesDiabetes Hiatal hernia / refluxHiatal hernia / reflux

Prophylaxis / Aspiration (con’t)Prophylaxis / Aspiration (con’t)

Critical valuesCritical values

– Volume > 25 ml.Volume > 25 ml.

– pH < 2.5pH < 2.5

Prophylaxis / Aspiration (con’t)Prophylaxis / Aspiration (con’t) NPO GuidelinesNPO Guidelines– NPO after midnightNPO after midnight» Tradition of strict enforcementTradition of strict enforcement»Now being challengedNow being challenged»Clear liquids may be o.k.Clear liquids may be o.k.»Dehydration and hypoglycemiaDehydration and hypoglycemia

Pharmacologic PreparationPharmacologic Preparation

Reduce gastric volumeReduce gastric volume

Increase gastric pHIncrease gastric pH

Increase gastric motilityIncrease gastric motility

AnticholinergicsAnticholinergics

Atropine / RobinulAtropine / Robinul

Probably not effectiveProbably not effective

Relax lower esophageal toneRelax lower esophageal tone

Have CV side effectsHave CV side effects

Histamine-Receptor AntagonistsHistamine-Receptor Antagonists Cimetidine / RanitidineCimetidine / Ranitidine Reduce gastric acid secretionReduce gastric acid secretion– Increase gastric pHIncrease gastric pH

Few side effectsFew side effects Give H.S. and A.M..Give H.S. and A.M..

Histamine Receptor Antagonists (con’t)Histamine Receptor Antagonists (con’t)

CimetidineCimetidine– Slows metabolism of other drugsSlows metabolism of other drugs

RanitidineRanitidine– More effectiveMore effective– Does not alter hepatic functionDoes not alter hepatic function

AntacidsAntacids Neutralize stomach acidsNeutralize stomach acids Onset is rapidOnset is rapid Increase gastric volumeIncrease gastric volume

– Antacid can be aspiratedAntacid can be aspirated

Use Use onlyonly non-particulate non-particulate antacidsantacids

MetoclopramideMetoclopramide

Gastrokinetic agentGastrokinetic agent

– Increases upper GI motilityIncreases upper GI motility

– Increases G.E. sphincter toneIncreases G.E. sphincter tone

– Relaxes pyloris and duodenumRelaxes pyloris and duodenum

Metoclopramide (con’t)Metoclopramide (con’t) Has antiemetic propertiesHas antiemetic properties May be offset by atropine or May be offset by atropine or

opioidsopioids Combine with HCombine with H22 antagonist antagonist Do notDo not use on bowel cases use on bowel cases

AntiemeticsAntiemetics Emesis is cause for admissionEmesis is cause for admission– Treatment is cost effectiveTreatment is cost effective

Treat high risk patientsTreat high risk patients– History of N and VHistory of N and V– Ophthalmologic surgeryOphthalmologic surgery– Gyn proceduresGyn procedures– ObesityObesity

Antiemetics (con’t)Antiemetics (con’t)

DroperidolDroperidol

– Effective in low doseEffective in low dose

MetoclopramideMetoclopramide

– Antiemetic effect in addition to Antiemetic effect in addition to

reduction in gastric volumereduction in gastric volume

Antiemetics (con’t)Antiemetics (con’t)

OndansetronOndansetron

– Highly effective new drugHighly effective new drug

– Very expensiveVery expensive

– Good rescue drugGood rescue drug

AnticholinergicsAnticholinergics AntisialagogueAntisialagogue– GlycopyrrolateGlycopyrrolate– Ophthalmic proceduresOphthalmic procedures– ENT proceduresENT procedures

Vagolytic effectVagolytic effect– AtropineAtropine

Anticholinergics (con’t)Anticholinergics (con’t)

Sedation and amnesiaSedation and amnesia

– ScopolamineScopolamine

See Barash for side effectsSee Barash for side effects

ClonidineClonidine

AntihypertensiveAntihypertensive

– Alpha-2 blockerAlpha-2 blocker

Produces sedationProduces sedation

Reduces anesthetic requirementsReduces anesthetic requirements

Acute withdrawal causes reboundAcute withdrawal causes rebound

Other Pre-op MedicationsOther Pre-op Medications

AntibioticsAntibiotics

– Ordered by surgeonOrdered by surgeon

– Protocol for valvular heart Protocol for valvular heart

diseasedisease

– Give slowlyGive slowly

Other Preop Medications (con’t)Other Preop Medications (con’t)

SteroidsSteroids

– Adrenals may be suppressed up Adrenals may be suppressed up

to one year after taking steroidsto one year after taking steroids

– Hydrocortisone 100 mg IVHydrocortisone 100 mg IV

Other Preop Medications (con’t)Other Preop Medications (con’t)

InsulinInsulin

– Agree on plan prior to surgeryAgree on plan prior to surgery

– AlwaysAlways start IV with dextrose start IV with dextrose

prior to giving insulinprior to giving insulin

Other Preop Medications (con’t)Other Preop Medications (con’t) Insulin (con’t)Insulin (con’t)– Treatment plansTreatment plans»No insulinNo insulin»1/2 dose of insulin1/2 dose of insulin» Insulin infusionInsulin infusion

Pediatric ConsiderationsPediatric Considerations Always approach a child as if Always approach a child as if

you will have to do him/her you will have to do him/her againagain

Use oral medication where Use oral medication where possiblepossible

Consider needs of the parentConsider needs of the parent

Small InfantsSmall Infants

Separation not a problemSeparation not a problem

High vagal toneHigh vagal tone

– Consider anticholinergicConsider anticholinergic

Preschool ChildrenPreschool Children Separation extremely traumaticSeparation extremely traumatic Use oral premedicationUse oral premedication– VersedVersed– FentanylFentanyl

Anticholinergic after asleepAnticholinergic after asleep Avoid cyclobrutaneAvoid cyclobrutane

Older ChildrenOlder Children Assess level of anxietyAssess level of anxiety Include in decision makingInclude in decision making Premedicate as appropriatePremedicate as appropriate Pre-op visit extremely Pre-op visit extremely

importantimportant