Estudo comparativo de duas doses de lidocaína 2% para bloqueio do nervo pudendo em gatos.

Abstract

Comparative study of two doses of lidocaine 2% for pudendal nerve block in cats. Feline Lower Urinary Tract Disease is a pathological syndrome of complex etiology with several predisposing factors, which can lead the animal to urethral obstruction. Once diagnosed, its treatment is of emergency, especially in cases where there is obstruction, proceeding to the patient's urethral examination. Among the types of anesthesia used for this, the locoregional anesthesia stands out for its safety, simplicity and effectiveness. The objective of this study was to compare the effects of two doses of lidocaine for pudendal nerve block in healthy cats. The experiment was carried out in the premises of the Biotério belonging to the Center for Health and Rural Technology of the Federal University of Campina Grande, Campus de Patos - PB. Nine male cats, healthy, weighing on average 3.5 ± 0.5 kg were used. Each animal was weighed before anesthetic procedure, restrained, submitted to general inhalation anesthesia and soon after the anesthetic technique for pudendal nerve block was performed. Each animal was subjected to two blocking protocols with a interval of 15 days between each anesthesia: 0.05mL/kg (Group A) and 0.1mL/kg (Group B), bilaterally. Were evaluated: latency, extent and duration of the anesthetic block; lateral and medial reflexes interdigital; anal reflex; and posture/gait. The pudendal nerve block occurred in only two animals in the Group A and five animals in the Group B. Regarding the period of latency, there was no difference between the groups, and it was one minute. In the group A, anesthetic period of 31 ± 2 minutes was observed and in the group B 33 ± 15 minutes, with no statistical difference. As to the extent of the blockade assessed by urethral catheter, in the animals of the group A and B in which the perineural block was effective, the catheter was allowed to pass through the urethral ostium, external urethral sphincter, penile urethra and pelvic urethra. There was no statistical difference between the groups regarding the interdigital reflexes analyzed. There was a significant difference regarding the anal reflex at some moments in the group B and between groups. In two animals of the group A there was concomitant blockade of the sciatic nerve while in the Group B this occurred in four animals. It can be concluded, the results of the experiment, that the use of lidocaine in the dose of 0.1 mL/kg/nerve to pudendal nerve block, is effective in most animals, and reducing the dose to 0.05 mL/kg/nerve decreases this effectiveness and does not avoid the concomitant blockade of the sciatic nerve.