cis-Atracurium in dogs with and without porto-systemic shunts.
OBJECTIVE
To evaluate the non-depolarizing neuromuscular blocking drug cis-atracurium in dogs with porto-systemic shunts, and to compare it in clinically normal animals.


METHODS
Thirteen dogs of mixed breed and sex, aged between 3 and 31 months old, weighing 2.2-25.5 kg, with ASA physical status II-IV, and undergoing surgical attenuation of porto-systemic shunt. A control group of 11 bitches of mixed breed, between 8 and 60 months old, and weighing 4.5-41.0 kg, all ASA physical status I, undergoing routine ovarohysterectomy were also studied.


METHODS
Pre-anaesthetic medication was an opioid analgesic, given either alone or in combination with acepromazine. Following induction of general anaesthesia with intravenous (IV) propofol and oro-tracheal intubation, anaesthesia was maintained using isoflurane in either oxygen or oxygen and nitrous oxide. Ventilation was controlled. The train of four (TOF) technique was used to monitor neuromuscular blockade. An initial dose of 0.1 mg kg(-1)cis-atracurium was given IV and additional doses of 0.03 mg kg(-1)cis-atracurium were administered when at least one twitch of the TOF was present.


RESULTS
Except for one dog that was killed during surgery because its anomaly was inoperable, all animals recovered satisfactorily from anaesthesia and surgery. In dogs with porto-systemic shunt, onset of neuromuscular blockade was 3.1 +/- 1.1 minutes (mean +/- SD) and in control dogs was 3.4 +/- 0.7 minutes (not significantly different). Neuromuscular blockade lasted 34 +/- 13 minutes in dogs with porto-systemic shunt and 29 +/- 17 minutes in control dogs (not significantly different).


CONCLUSIONS
The presence of porto-systemic shunt did not affect the rate of onset or duration of action of cis-atracurium.


CONCLUSIONS
cis-Atracurium may have a use in veterinary anaesthesia for producing neuromuscular blockade in dogs with hepatic insufficiency, including those with porto-systemic shunt.
Adams
Wendy A
WA
University Department of Anaesthesia, University Clinical Departments, Liverpool, UK. wendyadams5@hotmail.com
Mark Senior
Jonathan
J
Jones
Ronald S
RS
Williams
John M
JM
Gleed
Robin D
RD
D000768:Anesthesia, General / Q000662:veterinary; D000818:Animals; D001279:Atracurium / Q000378:metabolism / Q000627:therapeutic use*; D004283:Dog Diseases / Q000601:surgery*; D004285:Dogs; D005260:Female; D008297:Male; D003473:Neuromuscular Nondepolarizing Agents / Q000378:metabolism / Q000627:therapeutic use*; D011170:Portasystemic Shunt, Surgical / Q000662:veterinary*
D003473:Neuromuscular Nondepolarizing Agents; D001279:Atracurium