Big Game Flashcards
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%
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
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
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
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
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
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
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
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
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
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
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
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
Other Features of Giraffes
Thick Skin
Potential for malignant hyperthermia like syndrome during anesthesia
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
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
