Effect of general anesthesia and minor surgical trauma on urine and serum measurements in horses.
OBJECTIVE
To characterize the effect of general anesthesia and minor surgery on renal function in horses.


METHODS
9 mares with a mean (+/- SE) age and body weight of 9+/-2 years and 492+/-17 kg, respectively.


METHODS
The day before anesthesia, urine was collected (catheterization) for 3 hours to quantitate baseline values, and serum biochemical analysis was performed. The following day, xylazine (1.1 mg/kg, IV) was administered, and general anesthesia was induced 5 minutes later with diazepam (0.04 mg/kg, IV) and ketamine (2.2 mg/kg, IV). During 2 hours of anesthesia with isoflurane, Paco2 was maintained between 48 and 52 mm Hg, and mean arterial blood pressure was between 70 and 80 mm Hg. Blood and urine were collected at 30, 60, and 120 minutes during and at 1 hour after anesthesia.


RESULTS
Baseline urine flow was 0.92+/-0.17 ml/kg/h and significantly increased at 30 and 60 minutes after xylazine administration (2.14+/-0.59 and 2.86+/-0.97 ml/kg/h respectively) but returned to baseline values by the end of anesthesia. Serum glucose concentration increased from 12+/-4 to 167+/-8 mg/dl at 30 minutes. Glucosuria was not observed.


CONCLUSIONS
Transient hyperglycemia and an increase in rine production accompanies a commonly used anesthetic technique for horses. The increase in urine flow is not trivial and should be considered in anesthetic management decisions. With the exception of serum glucose concentration and urine production, the effect of general anesthesia on indices of renal function in clinically normal horses is likely of little consequence in most horses admitted for elective surgical procedures.
Department of Surgical and Radiological Sciences, School of Veterinary Medicine, University of California, Davis 95616, USA.
Zara E
ZE
Watson
Eugene P
EP
Steffey
Linda M
LM
VanHoogmoed
Jack R
JR
Snyder
D000316:Adrenergic alpha-Agonists / Q000494:pharmacology; D000768:Anesthesia, General / Q000662:veterinary*; D018685:Anesthetics, Inhalation / Q000494:pharmacology; D018686:Anesthetics, Intravenous / Q000494:pharmacology; D000818:Animals; D001774:Blood Chemical Analysis / Q000662:veterinary; D001786:Blood Glucose / Q000187:drug effects; D001794:Blood Pressure / Q000187:drug effects; D003975:Diazepam / Q000494:pharmacology; D005260:Female; D006736:Horses / Q000097:blood* / Q000601:surgery / Q000652:urine*; D007530:Isoflurane / Q000494:pharmacology; D007668:Kidney / Q000378:metabolism*; D013511:Minor Surgical Procedures / Q000662:veterinary*; D016482:Urinalysis / Q000662:veterinary; D014991:Xylazine / Q000494:pharmacology
D000316:Adrenergic alpha-Agonists; D018685:Anesthetics, Inhalation; D018686:Anesthetics, Intravenous; D001786:Blood Glucose; D014991:Xylazine; D007530:Isoflurane; D003975:Diazepam