AVIAN ANESTHESIA & SURGERYKim HealyVETS 247 Exotic Animal Medicine and NursingDr. MeckelSpring 2008

Anesthetic ProceduresSurgical sexingNot as commonly done now DNA testingAbscess/Wound repairRepair bone fracturesForeign body removalGrowth removals

Anesthetic ProceduresRadiographyEndoscopyRepair beak abnormalitiesScissor beakReproductive problemsEgg-boundMany more

Preanesthetic PeriodComplete HistoryPhysical ExamDiagnosticsCBC/Chem+/- Radiographs or UltrasoundStabilization for critical patientsFasting: 0-2 hours prior to procedure

PremedicationRarely usedStress from handlingUnpredictability of injectable drugs Anticholinergics (Atropine, Glycopyrrolate)If history of bradycradiaOpioids (Butorphanol)Reversible

InductionInhalants preferred methodIsoflurane or SevofluraneIso: less cardiac s/e

BenefitsRapid induction and recoveryRapid adjustments to anesthetic depthsLow organ toxicity

InductionInjectablesUnpredictable effectsSide effectsExtended recovery times

Ketamine +/- BenzodiazepinesLong & stormy recoveryPropofolRespiratory depressionStormy recovery

InductionMask

Commercially madeHome madePlastic bottles or syringe cases

Smaller patientsWhole head inside mask

IntubationCan use mask for very short procedures

Intubation provides:Manual ventilationPrevents aspiration

Non-rebreathing systemLess than 7kg

IntubationConcentric (complete) tracheal ringsLess flexible

Dont inflate cuff of endotracheal tubeOr, use uncuffed tubes Cole

Inflated cuff can cause pressure necrosis of trachea and sloughing of mucosa

Intubation

IntubationAir sac cannulaHead/beak proceduresClearing tracheal obstructionCaudal thoracic air sacThrough lateral body wallTypically left side larger air sacCan be left in for several daysE-collar

Air Sac Cannulation

Local AnesthesiaExample LidocaineNot recommendedNecessary dose higher than toxic dose, especially in smaller birdsRestraint of an awake bird is difficult

Surgical PrepAvoid heat loss!High surface area to volume ratio = lose heat quicklyPluck only necessary feathersPluck in opposite directionChlorexidine or Betadine scrubSalineAlcohol will cause heat lossTransparent sterile drapeRetains heatEasier to monitor patient

Transparent Drape

MonitoringManualAuscult heart rateStethoscope, esophageal stethoscopeObserve breathingCan be difficult to visualizeLungs rigid, no diaphragmMuscular movement of ribs/sternumRelaxed when anesthetizedShivering = too light

MonitoringECG Heart activityLarger birdsSmaller birdsMachine that can register rapid heart rateDoppler Blood pressureMedial metatarsal arteryRadial arteryPulse Oximeter Oxygen saturationFemur, foot, toe, radiusCan be difficult to get a readingCloacal or esophageal thermometer

Monitoring Blood Pressure

CatheterizationReplace fluids lostMaintain blood pressureBlood TransfusionIV Dextrose

Not often doneDifficult to monitor blood pressureAvoid overhydration

CatheterizationIntravenous (IV)Fragile veins: long-term is difficultJugular, basilic, medial metatarsal veins

Intraosseous (IO)BoneDistal ulna

Intraosseous Catheter

Anesthetized Patient a/b- et tube c- IVC d- IVF e- pulse ox

Thermal SupportHigh surface area to volume ratio = lose heat quicklyHeated surgery tableWater circulating blanketForced air blankets (Bair hugger)NO Heat lamps/heating pads NOT RECOMMENDED! thermal burns even on low setting

Heat Support

IPPVIntermittent Partial Pressure VentilationBaggingMechanical VentilatorInflates and circulates air through air sacs1-4 times per minuteDo not exceed 15mm H2OOverinflation, rupture of air sacs

IPPV - Bagging

RecoveryIncubatorStabilize temperatureOxygen supportWrapped in towelRemove endotracheal tubeChewing/swallowing, head shaking, flapping wingsFeed small amount of food or few drops 50% dextrosehypoglycemia

Incubator

Instruments & EquipmentSmall specialized surgical instrumentsOphthalmology instrumentsDelicate and preciseLaserCauterizes for hemostasisShorter surgical/anesthesia timesEndoscope

EquipmentOptical MagnificationBinocular head setsmicroscope

SutureFine suture for thin skin4-0 to 8-0Tapered needleTissue glue

Suture

Sources CitedBallard, B., & Cheek, R. (2003). Exotic Animal Medicine for the Veterinary Technician. Iowa: Blackwell Publishing.Tully, Jr., T.N., & Mitchell, MA. (2001). A Technicians Guide to Exotic Animal Care. Colorado: AAHA Press.Nielsen, L. (1999). Chemical Immobilization of Wild and Exotic Animals. Iowa: Iowa State University Press.Tseng, F.S., & Kaufman, G. Avian Anesthesia and Surgery. Retrieved March 15, 2008, from Tufts University Open Courseware. Web site: http://ocw.tufts.edu/Content /5/ lecturenotes/215768Gunkel, C., & Lafortune, M. (2005). Current Techniques in Avian Anesthesia. Seminars in Avian and Exotic Pet Medicine, 14,4, 263-276. Retrieved March 15, 2008, from Science Direct Database.Avian Surgery: To Cut is to Cure. (2006). Exotic Pet Veterinarian. Retrieved March 15, 2008, from http://www.exoticpetvet.net/avian/surgery.htmlExotic Animal Anesthesia, Perioperative Support, and Surgical Instrumentation. Michigan Veterinary Medical Association. Retrieved March 15, 2008, from http://www.michvma.org/

Fasting depends on size of birdHigh metabolic rate prevent hypoglycemiaMost avian speciesCole tube smaller and no cuffInstead of endotracheal intubationAir sac cannulation indicatedHole made through lat body wall into c.t. air sacLocal anesthetics, such as lidocainenot recomm b/c the necess dose is usually higher than what considered toxic dose, esp in small birds Awake restraint - stressfulDifficult to visualize inspiration & expiration b/c lungs are rigid/no diaphragmrely on movement of the ribs and sternum for ventilation relaxed when anesthetized medial metatarsal artery on the leg or radial artery on the wing Jugular, basilic vein on the wing, medial metatarsal vein on the leg

An anesthetized blue and gold macaw. Note the ET tube and Ayres T-Piece system (A), the mouth gag made of rolled gauzes (B), intravenous catheter (C) and continuous fluid infusion via a fluid pump (D), and pulse oximeter probe (E). A Doppler flow detector is also commonly used in birds but is not shown in this picture. forced air blankets (Bair hugger) - cumbersomeheat lamps/heating pads not recommended (in any P) thermal burns even on low setting remove et tube when starts to awaken Attempting to flap wings