Effect on pulse rate and blood pressure of premedication and epidural anaesthesia in the sow

Abstract

Three groups of adult, healthy sows were given (i) azaperone 2 mg/kg intramuscularly (im), (ii) azaperone 2 mg/kg with atropine 0.02 mg/kg im, and (iii) azaperone 4 mg/kg im, while a fourth group was given epidural anaesthesia (lignocaine 2% with adrenaline) after premedication with azaperone 2 - 4mg/kg with or without atropine 0.02 mg/kg im. Pulse rate (P) and systolic (SBP), mean (MBP) and diastolic (DBP) arterial blood pressures were measured using an automatic oscillometric method. Systolic (SBP), mean (MBP) and diastolic (DBP) blood pressures were reduced to 65–70% of control values in all the first three premedication groups, but there was a marked individual variation; the larger azaperone dose seemed to give a faster decline, and atropine did not prevent the fall. Pulse rate (P) showed a transitory rise in the two groups not given atropine. There were no other significant differences between these three groups. Epidural anaesthesia had no significant additional effect on any of the parameters measured.