Efeito da clonidina e hialuronidase associada à lidocaína na anestesia peribulbar em cães submetidos à cirurgia de catarata

Abstract

Among the regional anesthesia techniques, peribulbar block is becoming increasingly used for providing akinesia, with less risk of complications. Clonidine is a α₂ adrenoceptor agonist, commonly used as an adjuvant in retrobulbar, peribulbar and subtenon block in medicine, extending akinesia and analgesia. Hyaluronidase is an enzyme widely used as an adjuvant in orbital, which purpose is to facilitate the spreading of local anesthetic in the eye space. The objective of this study was to evaluate if the addition of clonidine and hyaluronidase associated with lidocaine 2% in peribulbar anesthesia, promotes sufficient block for accomplishment of cataract surgery. In the prospective study included 14 patients of both sexes, who were administered 1 ml of lidocaine 2% more hyaluronidase 25 UTR/ml, associated with 1,5 μg /kg of clonidine diluted in 0,5 ml of solution sodium chloride 0,9%. They were assessed before, during and after anesthesia: pupillary diameter, bulbar centralization period (PCB), motor block duration (PDM), mean arterial pressure, heart rate, respiratory rate, peripheral arterial oxygen saturation and dosage of glucose. It was observed that the PCB was 51 ± 12 seconds with PDM 108 ± 24 minutes with duration of surgery of 58,7 ± 16,4 minutes. In relation to the pupil diameter, statistically significant differences was observed when compared this parameter at the time before blocking with time after the block. It is concluded that clonidine (1,5 μg/kg) more hyaluronidase (25 UTR/ml), added with lidocaine 2% in peribulbar anesthesia in cataract surgery, promoted efficiently eyeball centralization on a short time, and cause increased pupil diameter and length of bulbar akinesia sufientes for performing cataract surgery, with IOP values within normal limits and with few adverse events.