Cardiovascular pathology possibly associated with ketamine/xylazine anesthesia in Dutch belted rabbits.
OBJECTIVE
After myocardial necrosis and fibrosis was observed in five rabbits which had been anesthetized a variable number of times, the potential relationship of these lesions and anesthesia was evaluated in 35 other rabbits.


METHODS
Anesthesia was induced by intramuscular administration of ketamine and xylazine followed by infusion of lactated Ringer's solution also containing ketamine and xylazine. Group A rabbits (n = 9) were subjected to multiple anesthesias and were evaluated by echocardiography, thoracic radiography, electrocardiography, determination of serum coronavirus titer, vitamin E concentration, and complete necropsy. Prior to a single acute procedure followed by necropsy, group B rabbits (n = 11) were evaluated by echocardiography only. Group C rabbits (n = 10) had never been anesthetized and were necropsied after euthanasia. Group D rabbits (n = 5) had intermediate anesthesia exposure history and were evaluated by echocardiography only. Myocardial fibrosis was scored semi-quantitatively on a scale of 0 to 4.


RESULTS
Canine coronavirus test results were negative; hypovitaminosis E was evident, and fibrosis scores were significantly increased in group A, compared with group B or group C, rabbits.


CONCLUSIONS
Etiologic differentials included alpha2-agonist-mediated coronary vasoconstriction with associated myocardial hypoperfusion, hypovitaminosis E and free radical injury, and other anesthetic-induced physiologic trespass.
Marini
R P
RP
Division of Comparative Medicine, Massachusetts Institute of Technology, Cambridge, USA.
Li
X
X
Harpster
N K
NK
Dangler
C
C
D000758:Anesthesia; D000777:Anesthetics / Q000009:adverse effects*; D000818:Animals; D000914:Antibodies, Viral / Q000097:blood; D002318:Cardiovascular Diseases / Q000139:chemically induced / Q000662:veterinary*; D017934:Coronavirus / Q000276:immunology; D004452:Echocardiography; D005355:Fibrosis; D007649:Ketamine / Q000009:adverse effects*; D009205:Myocarditis / Q000139:chemically induced / Q000473:pathology / Q000662:veterinary; D009206:Myocardium / Q000473:pathology; D009929:Organ Size; D011817:Rabbits; D013047:Specific Pathogen-Free Organisms; D014810:Vitamin E / Q000097:blood; D014991:Xylazine / Q000009:adverse effects*
D000777:Anesthetics; D000914:Antibodies, Viral; D014810:Vitamin E; D014991:Xylazine; D007649:Ketamine