avian restraint & anesthesia · 2018-09-10 · avian & anesthesia christine fiorello, phd,...
TRANSCRIPT
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