AVIAN RESTRAINT & ANESTHESIA · 2018-09-10 · AVIAN & ANESTHESIA Christine Fiorello, PhD,...

AVIAN RESTRAINT & ANESTHESIA

Christine Fiorello, DVM, PhD, Dipl. ACZM

OBJECTIVELearn to safely restrain, anesthetize,

and provide appropriate analgesia for a bird

Physical RestraintManual (bare-handed)GlovesTowelNet

Common in falconry�– Diurnal raptorsOther species�–Ostriches

�• (not emus or rheas)�–Waterfowl�–Cranes

Hoods

Passerines & Small Psittacines

Large Psittacines

RaptorsCover with towel, then control feetCan use glovesIn falconry, birds are trained to the glove

Pre-anesthetic PreparationDedicated AnesthetistFasting

2-4 hoursDraw up ER drugs, reversalsAnalgesic planBe prepared to cancel or abort

Anesthetic morbidity & mortality is directly

related to anesthetic duration

TIME=LIFE

AnalgesiaPoor analgesics:�– Isoflurane�– Sevoflurane�– Propofol�– Benzodiazepines

Analgesic planDissociative anestheticsLocal anesthetics�– Toxicity �– overdosageNitrous oxide�– Underutilized�– DECREASED FiO2�– Expands gas filled spaces

�• Not air sacs

ANALGESIA

OpioidsKappa agonists�–Butorphanol (0.5-2.0

mg/kg) reduced MACMu receptor agonists�–Poor to no

response

ANALGESIA

NSAIDSNephrotoxicity�– Species sensitivity�– Long-term useFlunixin meglumine (0.1-1.0 mg/kg)Ketoprofen (1-2 mg/kg bid)Meloxicam (0.3 mg/kg sid)�– Preferred by many

ANALGESIA

InductionInjectables�–Propofol�–Ketamine

combinationsInhalants�–Isoflurane�–Sevoflurane

PropofolRequires vascular access�– Large birdsRespiratory depressionHypotensionShort durationPoor analgesic4-10 mg/kg IV

Ketamine CombinationsIV or IMAnalgesia?Prolonged recoveryPoor muscle relaxation

InhalantsRapid control of airway�– Mask at high %�– No chamber induction�– Intubate ASAPTurn down gas once induced�– Efficient respiration�– OverdosageMinimize dead space

IsofluraneLow tissue/blood solubilityCardiopulmonary depression�– Dose-dependent�– ArrhythmogenicityPoor analgesia�– Premed for painful

procedures

Lower solubilitiesLower potency�– Higher MACExpensiveShorter inductions and recoveries�– Not always an advantage

Sevoflurane

Ventilatory SupportEndotracheal tubeAir sac cannulaVentilator

Endotracheal intubationEndotracheal tube�– Uncuffed tube�– Catheter for tiny birds�– Remember in

resistanceTrachea relatively larger than mammalsComplete tracheal rings

VENTILATORY SUPPORT

Endotracheal IntubationVENTILATORY SUPPORT

Intubated birdAlways disconnect before moving or repositioning birdCause of tracheal strictures not completely understoodUse extreme care when handling

VENTILATORY SUPPORT

Airsac CannulationVENTILATORY SUPPORT

Non-rebreathing systemsLower resistanceEasy to adjust depthHigh-flow�–Rapid heat loss�–Wasteful

VENTILATORY SUPPORT

VentilationIPPV is critical�–Spontaneous breath-

ing does NOT ensure adequate ventilation

�–Every 6-10 seconds�–Manual or mechanicalWatch chest excursions

VENTILATORY SUPPORT

Thermoregulatory support

Water blanketsHeat lampsBair hugger�–Forced air warmer�–Most effective

Fluid SupportCrystalloids�– ½ strength LRS or saline (0.045%) + ½

strength dextrose (2.5%)�– ~ 25% remains in vascular space in 30 min�– 10 ml/kg/hour during surgeryColloids�– Hetastarch�– 10-15 ml/kg IV or IO

over 15 minutes

Do not use hypertonic solutions

Vascular accessEmergency drugsFluid supportPros and cons�– Delicate veins

�• IO may be preferable�– Difficult to secure�– May take time to get in

�• TIME=LIFE

FLUID SUPPORT

Intraosseous catheterFLUID SUPPORT

Ulna (not pelicans) or tibiotarsusSpinal needle, 22 to 18 gaHalf length of boneLidocaine and/or general anesthesiaPlacement assessment�– Basilic vein clearance�– Radiograph�– No evidence of SQ

accumulation

Intraosseous catheterFLUID SUPPORT

Syringe pumps

MEDFUSION 2010i

FLUID SUPPORT

AccurateSmall volume infusion�– Fluids�– DrugsUse regular syringesCan pre-program infusions

Blood transfusionFLUID SUPPORT

Available blood donors�–Same species�–Same genus�–Same order?

OxyglobinExpensiveHypertonicHypertensionEasy to fluid-overload patients

FLUID SUPPORT

Advantages�– Convenient�– EasyDisadvantages�– Slow absorption�– What would you want in an emergency ?

Do not use hypertonic solutions

FLUID SUPPORT

Subcutaneous fluids

Monitoring

Clear drapesEsophageal stethescopeTemperature probeETCO2 �— underutilizedDoppler-ulnar, tibiotarsal a.Pulse ox less useful in birds

Anesthetic DepthMuscle relaxationResponse to pain�– Feather plucking very

painfulPalpebral & corneal responseHeart & respiration rate�– Careful-HR may just before

arousal

MONITORING

Ulnar a. Tibiotarsal a.

Doppler flow detection

MONITORING

ECGMonitor HRDx arrhythmiasChallenging�– Fast rates�– Low amplitudeUse small clips or needles

MONITORING

RespirationWatch chest excursionsAssume hypoventilation�– Anesthetic depression�– Positional�– DiseaseCO2 stimulates respiratory drive�– Use lower RR when recovering birds

MONITORING

MONITORING

Blood gas analysisPaO2 OxygenationPaCO2 VentilationpH & PaCO2 Acid-base statusUlnar or metatarsal arteries

Pulse oximetry

Not valid in birdsTrends may be useful�–Pulse rate�–Pulse wave -/=

perfusion

MONITORING

End-tidal CO2 (capnography)

Very useful toolNot perfect�– Dead-space�– Sampling rate�– VolumeAwaits validation

MONITORING

TemperatureMONITORING

Esophageal = coreCloacal -/= coreContinuousNormal bird 104rF

RecoveryWrap bird in towel until able to standRemove perches from cage until bird can perch steadilyBirds often arrest at or just after extubation�– Be prepared

Prolonged recovery?

Anesthetic overdoseHypothermiaHypoglycemiaHypercapniaHypovolemia