EVALUATION OF THE CARDIOCIRCULATORY EFFECTS IN MARES SUBMITED TO PERINEAL INCISION AFTER EPIDURAL INJECTION OF LIDOCAINE PLUS NaCl 0,9%, MORPHINE OR BUTORPHANOL. / AVALIAÇÃO DOS EFEITOS CARDIOCIRCULATÓRIOS EM ÉGUAS SUBMETIDAS A ESTÍMULO CIRÚRGICO PERINEAL APÓS INJEÇÃO EPIDURAL DE LIDOCAÍNA ASSSOCIADA À SOLUÇÃO DE CLORETO DE SÓDIO 0,9%, À MORFINA OU AO BUTORFANOL.

ABSTRACT

The epidural administration of analgesics has been used as an alternative to prevent nociceptive stimuli and in equine analgesia. This study was aimed at evaluating the behavior, cardiocirculatory parameters (heart rate-HR, respiratory rate-RR and average arterial pressure-AAP) and rectal temperature after epidural injection of lidocaine plus NaCl 0.9% (L+S - 2.5 mg/kg), lidocaine plus butorphanol (L+B - 2.5 mg/Kg and 0.04 mg/Kg), or lidocaine plus morphine (L+M - 2.5 mg/kg) in 21 mares undergoing perineal incision. Each parameter was measured before (T0) and at five minutes (F5), at 10-minute intervals up to 60 minutes (T60), and at 15-minute intervals up to 180 minutes (T180) after the drugs were administered epidurally and perineal incision was performed. After these moments, HR, RR and RT were also measured at T360, T720 and T1440. Using such doses and associations of analgesics, no behavior changes, such as euphoria, excitement or ataxia, were observed. Regarding HR, there was no statistical differences (P < 0.05 in the Student-N-Keuls test) among treatments. The group that was given the L+M association showed a milder decrease in respiration, which differed significantly in relation to the L+S group at T20 and T1440. Regarding the rectal temperature at T360 and T1440, L+B and L+M groups showed a significant variation ( P £ 0 of SNK Test) in relation to L+S, being signi