The effects of anesthesia on the clinical chemistry of New Zealand white rabbits

The effects of four anesthetics on various plasma biochemical parameters were investigated in the New Zealand White rabbit. Fifty animals were assigned to five treatment groups (n = 10 per group): control (1 ml normal saline intravenously [i.v.]); ketamine (10 mg/kg i.v.) with either xylazine (3 mg/kg i.v.) or diazepam (2 mg/kg i.v.); pentobarbitone (30 mg/kg i.v.); and thiopentone (20 mg/kg i.v.). Plasma cholesterol, triglycerides, lactate dehydrogenase (LDH), sodium, potassium, chloride, calcium and phosphorus concentrations were measured by an autoanalyzer. Blood samples were obtained at six time-points: before injection and at 10, 30, 60, and 120 min and 24 h after injection of the anesthetic or saline. Plasma biochemical levels were compared to control group and baseline (time 0) levels. Plasma cholesterol concentrations significantly increased in the ketamine-diazepam (P < 0.01) and pentobarbitone (P < 0.05) groups, whereas plasma triglycerides significantly increased in the ketamine-xylazine (P < 0.01) and ketamine-diazepam (P < 0.01) groups. Plasma LDH significantly increased in the ketamine-diazepam group (P < 0.001) and decreased in the pentobarbitone group (P < 0.01). Plasma sodium levels significantly increased after ketamine-xylazine (P < 0.05), ketamine-diazepam (P < 0.05), and thiopentone (P < 0.05) administration; plasma potassium significantly increased after ketamine-xylazine (P < 0.05) and decreased in the pentobarbitone group (P < 0.05); plasma chloride (P < 0.01) and phosphorus (P < 0.05) significantly increased after ketamine-diazepam treatment whereas plasma calcium levels increased (P < 0.05) after ketamine-xylazine injection. From the results observed so far, we concluded that plasma levels of some biochemical parameters significantly increased or decreased after anesthetic administration. Therefore, caution is required in interpreting data on plasma biochemical parameters from anesthetized rabbits, particularly during the recovery period.