Anaesthesia in reptiles Zdenek Knotek, DVM, PhD Avian and Exotic Animal Clinic University of Veterinary and Pharmaceutical Sciences Brno Czech Republic
Sedation
big tranquillisers (chlorpromazine 10 mg/kg IM) small tranquillisers (diazepam 0.20 – 0.60 mg/kg IM) tiletamine/zolazepam
efficient
Tiletamine
2 (ethylamino)-2-(2thienyl)cyclohexanon
phencyclidine derivat (50 % of the phenc. effect) 2 - 3x stronger than ketamine dissociative anaesthetics
Dissociative anaesthetics + induce diminished tone and reduced impulse transmission - without muscle relaxation - have a limited capacity of inducing visceral analgesia - are not appropriate for use as stand-alone anaesthetic in larger and abdominal surgeries
Zolazepam
4 - (-o- Fluorophenyl)-6, 8-dihydro-1,3,8, trimethyl-pyrazolo(3,4e)(1,4)diazepin-7(1H)-one) benzodiazepin-family
Tiletamine - zolazepam + safety analgesia and myorelaxation free of side effects
- dependence on metabolism eliminated by liver + kidneys Tilest, Telazol, Zoletil
1:1
Indications for tiletamine-zolazepam anaesthesia in reptiles safe handling and transportation of aggressive lizards sedation and immobilization during some examinations (radiography, MRI, endoscopy, USG, biopsy) preparing intubation before inhalation anaesthesia (crocodiles, chelonians aggressive lizards, poisonous snakes)
Anaesthesia Injection or inhalation anaesthesia for reptiles? Injection optimal site ? active metabolism (kidney, liver) !!! recovery (long-lasting) !!! antidote regulation !!! BW influence price (drug, equipment) Inhalant metabolism + equipment !!! price ? technique (intubation in agressive - dangerous animals)
Isoflurane only 0.3% is metabolised in the body fast onset of deep surgical anaesthesia fast recovery - free of complications excellent myorelaxation in patients with renal or hepatic damage does not irritate the myocardium
Isoflurane
Lizards < 1 kg > 1 kg
Premed.
Form
+
mask 5% 1,5 - 2,5% intubation 4 - 5% 1,5 - 2,5%
Snakes +/Turtles + Crocodiles +
Induction
intubation int./mask intubation
5% 5% 4%
Surgery
1,5 - 2% 3–4% 1–2%
Crocodiles Trachea
closed with the valve
Introduction
tiletamine/zolazepam
Surgery
isoflurane
Tiletamine - zolazepam Crocodiles Crocodiles
5 - 10 mg/kg IM sedative 10 – 40 mg/kg IM surgery 1 - 2 mg/kg IM
Crocodiles
4 - 8 mg/kg IM
Crocodiles
5 mg/kg IM
Crocodiles
induction immobilization
2 - 8 mg/kg IM induction
Lloyd (1999) Lloyd (2003) Fleming (2001) Haagner and Reynolds (1992)
Turtles, tortoises, terrapins Glottis
base of the tongue
Introduction
tiletamine/zolazepam
Surgery
isoflurane
Patient monitoring and control - chelonians reflexes head, neck, and leg/tail reflex jaw tone - turtles and terrapins skin sensitivity - disappear in deep palpebral reflex anaesthesia pulse oximetry
Tiletamine - zolazepam Chelonians
5 - 10 mg/kg IM
Raphael (2003)
good muscle relaxation
Chelonians
3 - 14 mg/kg IM
Chelonians
10 - 30 mg/kg IM
not enough
good muscle relaxation
4 - 88 mg/kg IM
Chelonians
not enough for surgery
Chelonians
3 - 5 mg/kg IM induction
45 mg/kg IM intubation 90 mg/kg IM minor surgery 15 - 20 mg/kg IM Chelonians Chelonians
restraint, intubation
Schobert (1987) Frye (1991) Boever and Caputo (1982) Heard (2001) Apelt (1993)
60 - 90 mg/kg IM Risk – kidneys/liver
Snakes Glottis opens in the floor of the mouth cavity Direct intubation easy Mask Introduction Surgery
tiletamine/zolazepam isoflurane
Patient monitoring and control - snakes reflexes head, neck, and frontal body lifting reflex righting reflex - fast correction of position skin sensitivity - disappears in deep anaesthesia pulse oximetry
Tiletamine - zolazepam Snakes
3 - 5 mg/kg IM
Mitchell (2003)
minor surgery
Snakes
25 mg/kg IM rapid and safe sedation
Snakes
15 mg/kg IM
Snakes
15 - 29 mg/kg IM
Snakes
3 - 5 mg/kg IM
Snakes
5 - 10 mg/kg IM
Snakes
15 - 30 mg/kg IM
minor surgery
induction
immobilization
minor surgery
Stirl (1997) Schobert (1997) Gray et al. (1974) Heard (2001)
Lizards Glottis Direct intubation Mask Introduction Surgery
floor of the mouth cavity easy - difficult
tiletamine/zolazepam isoflurane
Patient monitoring and control - lizards reflexes head, neck, and frontal body lifting reflex skin sensitivity - disappears in deep anaesthesia pulse oximetry
Patient monitoring and control temperature blood pressure SpO2 heart frequence ventilation TCO2
Tiletamine - zolazepam Lizards
4 - 8 mg/kg IM
Heard (2001)
handling
Lizards
4 - 6 mg/kg IM immobilization
Lizards
10 - 15 mg/kg IM
Lizards
25 - 40 mg/kg IM
restraint, induction
surgery
Schumacher (2003)
Propofol short-lasting effect (20 minutes) IV turtles and tortoises 5 -10 mg/kg snakes 5 mg/kg lizards 5 - 10 mg/kg