Pressor Effects of Ephedrine in Cows with Segmental Lumbar Epidural Analgesia Induced by a Combination of Xylazine/Lidocaine

Abstract

Segmental lumbar epidural analgesia (SLEA) was performed in 17 Holstein cows (three cows were used twice at weekly intervals) by administration of a combination of xylazine/lidocaine (XL) through indwelling epidural catheters. The cows were divided into 5 groups, a control group and 4 treatment groups (n=4; 3 cows were used twice) . The cows of each group were given ephedrine hydrochloride 10 min before XL epidural injection at 0.2 mg/kg intravenously, 0.2 mg/kg epidurally, 0.5 mg/kg subcutaneously and 1.0 mg/kg subcutaneously, respectively. Control group, with no ephedrine treatment, showed about 20% decrease in mean arterial blood pressuae (MABP) at 30, 60, 90 and 120 min after XL epidural injection. MABP decreased about 10 and 15% in groups with epidural and intravenous ephedrine administration, respectively, and increased more than 20% with shorter duration of sedative effect in the group where 1.0 mg/kg ephedrine was administered subcutaneously. The group administered 0.5 mg/kg ephedrine subcutaneously maintained MABP at baseline level without affecting the analgesic and sedative effects of SLEA induced by XL.