Effects of subanesthetic doses of ketamine on hemodynamic and immunologic variables in dogs with experimentally induced endotoxemia.
OBJECTIVE
To determine the effects of ketamine hydrochloride on hemodynamic and immunologic alterations associated with experimentally induced endotoxemia in dogs.


METHODS
9 mixed-breed dogs.


METHODS
In a crossover study, dogs were randomly allocated to receive ketamine (0.5 mg/kg, IV, followed by IV infusion at a rate of 0.12 mg/kg/h for 2.5 hours) or control solution (saline [0.9% NaCl] solution, 0.25 mL, IV, followed by IV infusion at a rate of 0.5 mL/h for 2.5 hours). Onset of infusion was time 0. At 30 minutes, lipopolysaccharide (LPS; 1 microg/kg, IV) was administered. Heart rate (HR), systolic arterial blood pressure (SAP), plasma tumor necrosis factor (TNF)-alpha activity, and a CBC were evaluated.


RESULTS
Mean SAP was significantly reduced in dogs administered ketamine or saline solution at 2 and 2.5 hours, compared with values at time 0. However, there was no significant difference between treatments. At 1, 2, and 2.5 hours, dogs administered ketamine had a significantly lower HR than dogs administered saline solution. Although plasma TNF-alpha activity significantly increased, compared with values at time 0 for both groups, ketamine-treated dogs had significantly lower peak plasma TNF-alpha activity 1.5 hours after LPS administration. All dogs had significant leukopenia and neutropenia after LPS administration, with no differences detected between ketamine and saline solution treatments.


CONCLUSIONS
Administration of a subanesthetic dose of ketamine had immunomodulating effects in dogs with experimentally induced endotoxemia (namely, blunting of plasma TNF-alpha activity). However, it had little effect on hemodynamic stability and no effect on WBC counts.
DeClue
Amy E
AE
Department of Veterinary Medicine and Surgery, College of Veterinary Medicine, University of Missouri, Columbia, MO 65211, USA.
Cohn
Leah A
LA
Lechner
Elizabeth S
ES
Bryan
Margaret E
ME
Dodam
John R
JR
D000777:Anesthetics / Q000494:pharmacology*; D000818:Animals; D001794:Blood Pressure / Q000187:drug effects*; D018592:Cross-Over Studies; D004285:Dogs; D004305:Dose-Response Relationship, Drug; D019446:Endotoxemia / Q000139:chemically induced / Q000188:drug therapy / Q000662:veterinary*; D006339:Heart Rate / Q000187:drug effects*; D007649:Ketamine / Q000494:pharmacology*; D007962:Leukocytes / Q000187:drug effects; D009504:Neutrophils / Q000187:drug effects; D013997:Time Factors; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism
D000777:Anesthetics; D014409:Tumor Necrosis Factor-alpha; D007649:Ketamine