Anestesia epidural com diferentes doses de lidocaína em ovinos.

Abstract

Epidural anesthesia with different doses of lidocaine in sheep. This research was developed with the aim of comparatively evaluating the effects of two doses of lidocaine, in sheep, regarding the anesthetized area obtained and effects on some physiological variables. The study was carried out on the premises of the Veterinary Hospital of the Blood and Rural Technology Center of the Federal University of Campina Grande, Campus Patos - PB. Six non-pregnant, healthy sheep, two males and four females, aged 8.3≠1.2 months and weighing 22.9≠1.8 kg were used. Each animal was weighed and, after 15 minutes of rest, it was restrained to measure the physiological parameters that were analyzed. Then the animals were sedated with acepromazine at a dose of 0.05 mg/kg intravenously (IV). Each of the animals was submitted to two protocols, with an interval of days between each anesthesia: Group 1 - administration of 2% lidocaine - same procedure as in group 1, but in a volume of 0.4 mL/kg. Heart rate, electrocardiography, respiratory rate, body temperature and rumen motility were evaluated. All parameters were measured immediately before administration of acepromazine (T-15) and epidural anesthesia (T0) and at 15 (T15), 30 (T30), 45 (T45), 60 (T60), 90 (T90) and 120 (T120) minutes after this. Anesthesia (latency, duration, and extent of the desensitized area) was assessed using cutaneous pinching with a 30x7 needle. Ataxia was evaluated according to a scale: 0 - absent taxi; 1 - moderate ataxia and able to walk; 2 - ataxia was assessed as severe with new recumbency. In none of the parameters referring to anesthetic induction there was a significant difference between the groups. The maximum height of anesthesia reached was up to the sixth rib (T6) laterally and up to half of the sternum ventrally in group 1, and up to the fourth rib (T4) laterally and half of the sternum ventrally in group 2, which were obtained before 15 minutes and lasted an average of 60 minutes after administration of lidocaine. There was a reduction in respiratory rate and body temperature. Decubitus occurred at 1.5 ≠ 2.3 minutes and lasted 118.7 ≠ 19.8 minutes in Group 1. In Group 2, decubitus started immediately under anesthesia and lasted 151.8 ≠ 47.1 minutes. When reassuming the quadrupedal position, the animals presented ataxia grade 1 (moderate ataxia). It is concluded that epidural anesthesia with both volumes does not promote changes in cardiac physiology and rumen motility; that the association acepromazine-epidural anesthesia decreases respiratory rate and body temperature; and that the volume of 0.4 mL/kg does not increase the area or duration of anesthesia and causes transient muscle spasticity in 33% of the animals. kg.