Isoflurane anaesthesia in four sea lions (Otaria byronia and Zalophus californianus).
OBJECTIVE
To (1) evaluate a purpose-built chamber for inducing isoflurane anaesthesia in sea lions and (2) assess isoflurane as an anaesthetic for dental surgery in these species.


METHODS
Prospective case study.


METHODS
Four sea lions, aged between 5 and 12 years and weighing 74-110 kg, with dental disease.


METHODS
Sea lions were restrained in a custom-built acrylic chamber into which 5% isoflurane (vapourizer setting) was delivered in O(2) (30 L minute(-1)) from three anaesthetic machines. When the animals were recumbent, the chamber was opened and induction completed using a face mask. Anaesthesia was maintained with 1.5-3.0% isoflurane (vapourizer setting) for 10-15 minutes and after tracheal intubation, was maintained with 1.0-3.0% isoflurane (end-tidal) for 41-255 minutes, using a partial rebreathing system with CO(2) absorption.


RESULTS
During induction, the sea lions attempted to support their weight on their thoracic limbs before slipping into sternal or lateral recumbency. Sea lions underwent either root canal surgery, 'crowning' or canine tooth extraction. The animals were completely unresponsive during these operations and apnoea was never encountered at any point during anaesthesia. After surgery, the sea lions were placed into transport cages and their tracheae extubated once they began to move their heads. Thereafter, recovery from anaesthesia was smooth and no signs of distress were observed. Animals were able to raise their forequarters using their flippers within 1 hour of the operation and were returned to the aquarium about 2 hours after surgery.


CONCLUSIONS
The purpose-built induction chamber is safe for inducing isoflurane anaesthesia in spontaneously breathing sea lions and isoflurane is an effective anaesthetic in this species.
Yamaya
Yoshiki
Y
Animal Medical Center, Nihon University, Fujisawa, Kanagawa, Japan. yamaya@brs.nihon-u.ac.jp
Ohba
Shigeo
S
Koie
Hiroshi
H
Watari
Toshihiro
T
Tokuriki
Mikihiko
M
Tanaka
Shigeo
S
D000769:Anesthesia, Inhalation / Q000295:instrumentation / Q000662:veterinary*; D018685:Anesthetics, Inhalation / Q000494:pharmacology*; D000818:Animals; D005260:Female; D007530:Isoflurane / Q000494:pharmacology*; D008297:Male; D046070:Sea Lions / Q000502:physiology*
D018685:Anesthetics, Inhalation; D007530:Isoflurane