Big Game Flashcards by Ella Pittman

Zubinator

demand ventilator for megavertebrate anesthesia

o Portable, compressed O2 powered, venturi enhanced, manually triggered demand ventilator
o Can deliver large TV for animals 350-5500 kg
o Delivers FiO2 42%

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Large ETTs

Available in 35 mm ID x 1.6 meter length for intubation of animals 2000 -4000 kg, 45 mm ID x 1.8 meter length for animals > 4000 kg

Larger 52 mm ID x 1.8 meter length for animals > 5000

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Felids

General protocol: DA + a2
o Risk of hyperkalemia with 2

Can be trained for injection

Tigers: adverse reactions to Telazol – prolonged m rigidity, inability to stand for days

Laryngospasm

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Bears

Frequently captured in field
o Helicopter or ground darting (snared first)
o Can suffer physiologic derangements in snares

Fat deposits
o Consider time of year, relationship to hibernation

Hyperthermia

Sudden recoveries, esp with ketamine

General protocol: oral carfentanil mixed with honey

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Marsupials

Lower metabolic rate, higher doses of drugs vs eutherians of similar size

Thermoregulation slow to develop
o No brown fat
o Cooling, panting via licking

Venipuncture sites: ventral/lateral coccygeal, others similar to carnivores

Intubation: narrow oral cavity, small gape

General protocol: mask induction or a2+DA

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Rhinos

Anesthetized in captivity or field
o Field: pursued by helicopter

Protocol: etorphine +/- azaperone (reduce opioid-induced excitement, vasodilate)
o Alternatively: carfent + thiafentanyl
o Hyaluronidase
o Butorphanol: keeps patient standing, improved ventilation
 Walked into crate
 20mg torb/mg etorphine

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Complications with Rhinos

Worse in White Rhinos

Tachycardia, Hypertension

Severe hypoventilation, hypoxemia – L shifted O2 curve with P50 ~17mm Hg
–PaO2 better in sternal recumbency
–Lateral recumbency prevents myopathy, increases dead space ventilation

Lactic acidemia, Hyperthermia, Tremors

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Etorphine in White Rhinos

sympathetic outflow
o Tachycardia – increased CO – increased PAP, PAOP, systemic hypertension
o Tremors increase VO2
o Partial antagonism with torb improves oxygen supply and demand balance

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Giraffes: size

Large size, cumbersome shape limits physical control during induction, recovery and limits manipulation once down
 Males can weigh almost 2000kg
 Long legs prone to stumbling, splaying –> fractures, nerve injuries

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Giraffes: CV Stream

To maintain cerebral circulation, maintain highest mean arterial pressure at level of heart compared to any animal studied
 MAP 200mm Hg in the heart, 400mm Hg in hind legs

Heart may be more prone to injury from oxygen during hypoxemia

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Giraffes: Edema Prevention in Dependent Areas

 Leg capillaries impermeable to protein:
 Pericapillary VC in legs
 Arterial/arteriolar wall hypertrophy in legs
 Prominent lymphatic system
 One way valves in veins, lymphatics
 Tight skin, fascia – antigravity suit

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Giraffes: Edema Prevention in Dependent Areas

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Giraffes Respiratory System

Large respiratory dead space due to long trachea, compensated by smaller than expected tracheal diameter, slow deep respirations, large tidal volume

Elongated skulls, narrow interdental spaces, caudal larynx
 Potential for difficult intubation
 Accumulation of pharyngeal fluid in larynx

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Other Features of Giraffes

Thick Skin

Potential for malignant hyperthermia like syndrome during anesthesia

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Giraffes + Long Neck

Long neck: acts as lever arm during inductions, recoveries if not controlled
 Mispositioning: airway obstruction, cramping, focal myopathies of neck muscles
 Must be massaged, moved during GA to prevent myopathies

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Drug Delivery, Protocols

IV access: jugular vein +/- auricular, facial veins

Free-Ranging
 Etorphine (M-99) +/- thiafentnail (A-3080) +/- hyaluronidase
 Azaperone not used if being transported
 Diprenorphine IV immediately upon recumbency

Captive
 Medet + keta +/- thiafentanil (more rapid onset, shorter DOA, slightly less resp depression)

Giraffe Anesthesia

o Mortality: 30-50% to <5%
o Fasting: other ruminants if captive, max 24 hrs – prone to regurgitate

Induction Environment for Giraffes

Zoo
 Induction shoot if possible
 Catwalk
 Halter with rope, pulley system
 Secure footing, no hazards

Field: darted, cast with ropes

Anesthetic Management of Giraffes

o Control/support head, neck
o Intubation: laryngoscopy with long blade, use of bougie vs digital intubation
o ETT 24-30mm ID, cuffed
o Demand valve

Giraffe Recovery

o Head, neck held down until giraffe can lift three strong men off
o Require good footing, sufficient room to be able to rock forward with neck to get legs under them

Analgesia in Giraffes

o NSAIDS: banamine, bute, ketoprofen
o Gabapentin

Hippos

Aggressive, large
o Nile (common) hippo weighs up to 2500kg

Retreat to water when threatened

Skin important for thermoregulation: think epidermis over thick dermis
o Viscous, alkaline secretions

Veins = difficult to locate
o Options for access include ventral tail, cephalic, median, palmer digital

Auscultation difficult

Mortality Rate in Hippos

35%

Protocols for Ax in Hippos

Etorphine + azaperone – can take up to an hr
 Diprenorphine or naltrexone for antagonism

Butorphanol-azaperone-medetomidine followed by sublingual ketamine

Intubation in Hippos

Fleshy tongue, redundant pharyngeal tissue, long soft palate o Laryngoscopy or digital intubation o 24-30mm ETT

Complications Assoc with Hippo Ax

o Drowning o Severe hypoventilation, hypoxemia

Elephant CV Physiology

 Large erythrocytes, fewer in number – comparable O2 carrying capacity  P 50 = 23-24 mm Hg, left shifted curve (similar to horses)  HR 25-30bpm  MAP ~100mm Hg

Elephant Resp Physiology

 RR 4-6bpm, fractional airway dead space 25-30%  Semi obligate nasal breathers, approximately 70%  Pleural adhesions, no pleural space – evolution for snorkeling

IV Access - Elephants

o IV access: auricular arteries, veins

Positioning following Immobilization in Elephants

Following darting, usually sit in sternal: important to find as quickly as possible as widely believed that do not ventilate adequately in sternal  Tolerate sternal recumbency for 15-20’  Roll into lateral with head pointed uphill Protect airway by extending trunk Palpate pulse on auricular artery: etorphine-immobilized elephants regardless of species have HR 50bpm, respiratory rate 5-7bpm

Hypoxemia Management in Elephants

 Respirator device developed to provide oxygen, IPPV to immobilized elephants in field  Driven off single MM oxygen cylinder, achieve partial pressures >400mm Hg O2 when oxygen delivered in synchrony with breathing pattern via 35mm ETT  Two demand valves

Intubation in Elephants

--Baseball bat gag --Blind technique, with hand guided insertion of tip into dorsal opening of glottis --Imperative that mouth opened wide enough to allow insertion of arm *Large molars, very narrow intermandibular space --Large fleshy epiglottis that free of cartilage: allows for tight seal formed between the trachea, opening to nares on roof of pharyngeal cavity *Easily pulled forward to allow access to glottis **Potential for challenge: very thick vocal cords that occlude entrance to trachea** *In coordination with breathing manually guide end of ETT into dorsal space of glottis where vocal folds thinner, more easily separated

Complications with Elephants

Pink Foam Syndrome Myopathy Severe hypoxemia, hypoventilation

Pink Foam Syndrome

 Opioids can cause pulmonary hypertension with pulmonary hemorrhage as a common sequelae  Pulmonary edema, bleeding manifest as pink foam  Commonly reported in South Africa where perform helicopter chase * Not seen with approach on foot  Potentially less problematic with lower doses of etorpine