RESUMO

Dez cães receberam administração epidural da associação de cloridrato de tiletamina e zolazepam, entre as vértebras L7 e S1, avaliando-se a analgesia pela observação dos padrões respiratório e comportamental, e pela aplicação dos filamentos de von Frey nos coxins plantares e ao redor do esfíncter anal externo. Não foram observadas as manifestações sistêmicas características da administração parenteral de anestésicos dissociativos, e todos os animais manifestaram completa analgesia, sendo que o emprego dos filamentos de von Frey permitiu testes de sensibilidade cutânea sem causar lesões teciduais. A técnica empregada promoveu ataxia e paresia, que perduraram por 41,25 (± 2,18) minutos, acompanhadas por relaxamento do esfíncter anal externo dos cães. Outros estudos sobre os efeitos da administração epidural da associação de cloridrato de tiletamina e zolazepam deverão ser efetuados, no que diz respeito a quantificar e qualificar a analgesia nesse período, bem como avaliar a possibilidade de realização de intervenções cirúrgicas cruentas, com essa técnica.

Ten dogs received an epidural administration of tiletamine HCl and zolazepam, between vertebrae L7 and S1. The analgesia was evaluated by observation breathing and behavioral patterns, and by the use of von Frey filaments applied to the external anal sphincter and footpads. Systemic manifestations from parenteral administration of dissociative anesthetics were not observed, and all the animals showed complete analgesia. The technique promoted ataxia and paresis which persisted for 41.25 (±2.18) minutes, followed by external anal sphincter myorelaxation. The von Frey filaments allowed cutaneous sensibility tests without causing any tissue lesion. Other investigations searching the tiletamine HCL and zolazepam effects should be performed in order to quantify and qualify the analgesia in that period, as well as to evaluate the possibility of accomplishment of painful surgical procedures with this technique.

Diez perros recibieron administración epidural de la asociación de clorhidrato de tiletamina y zolazepam, entre las vértebras L7 y S1, evaluándose la analgesia por observación de los estándares respiratorio y de comportamiento, y por la aplicación de los filamentos de von Frey en los asientos plantares y alrededor del esfínter anal externo. No fueron observadas las manifestaciones sistémicas características de la administración parenteral de anestésicos disociativos, y todos los animales manifestaron completa analgesia, siendo que el empleo de filamentos de von Frey permitió testes de sensibilidad cutánea sin causar lesiones en tejidos. La técnica empleada promovió ataxia y paresia, que perduraron por 41,25 (±2,18) minutos, acompañadas por relajamiento del esfínter anal externo de los perros. Otros estudios sobre los efectos de la administración epidural de la asociación de clorhidrato de tiletamina y zolazepam deberán ser efectuados, por lo que respecta a cuantificar y calificar la analgesia en ese período, bien como evaluar la posibilidad de realización de procedimientos quirúrgicos cruentos, con esa técnica.

Assuntos

RESUMO

OBJECTIVE: To evaluate the pre-emptive analgesic effect of pre-incisional epidural ketamine. STUDY DESIGN: A blinded, randomized experimental study. ANIMALS: Sixteen mixed breed mares, 7.6 ± 2.8 years old, weighing 352 ± 32 kg. METHODS: In a pilot study, an incision was made on one lateral thigh using a lidocaine block and no further analgesics, and it was verified that the nociceptive threshold was lower on the incised side than nonincised side (p ≤ 0.05), and that von Frey filaments evoked a pain response. The 16 animals were divided into group A (ketamine, n = 9) and B (saline, n = 7). An epidural catheter was inserted 24 hours before the trials. The thigh was shaved bilaterally, and the right side was blocked (incised side) using lidocaine. Twenty-five minutes later, ketamine (A) or saline (B) was administered epidurally. Five minutes later, a 10-cm skin incision was made on the right side, and then sutured. Nociceptive threshold was determined with von Frey filaments at 1, 3, and 5 cm around the incision at 15-minute intervals for 2 hours, then at 4, 6, and 8 hours. Behavioral alterations, heart and respiratory rates were recorded. Nociceptive thresholds from these points were averaged to obtain mean values at each time, converted to a logarithmic scale, and submitted to a nonparametric analysis (Mann-Whitney and one-way repeated measures anova test, p ≤ 0.05). RESULTS: After 8 hours, the global range score revealed reduced hyperalgesia (p < 0.01) around the incision in 92% (4.65-4.27) of evaluated intervals in group A (ketamine). There were no significant changes in behavior, heart and respiratory rates. CONCLUSIONS: It was concluded that pre-emptive epidural ketamine reduced post-incisional pain in the horse, and that von Frey filaments were able to quantify cutaneous sensitivity after tissue damage. CLINICAL RELEVANCE: Epidural ketamine injection can reduce post-incisional sensitivity in the horse.

RESUMO

Pre-emptive analgesic effects of epidural ketamine or morphine were compared using the von Frey filaments (VF). Fourteen mixed breed male or female dogs, weighing 12.5kg, divided into G1 (morphine, 0.1mg/kg; n=7) and G2 (ketamine, 0.2mg/kg; n=7) groups were used. Under sevoflurane anesthesia epidural injections were made by spinal needle inserted at lombo-sacral space. Subsequently, a 1.5cm cushion incision was made and immediately closed with a simple interrupted nylon suture and the inhalatory anesthesia was closed. Thirty minutes after the suture, the postincisional pain was measured by VF filaments at 0.3cm around the incision. These procedures were repeated every 30 min until 120 min and at 3, 4, 5, 6 and 24 hours after suturing. The VF filaments force expressed in grams were analyzed by non-parametric tests (Kruskal-Wallis or Mann-Whitney, P =0.05). No response to VF filaments was observed in G1 dogs. The VF force was reduced progressively in the G2 dogs, from 90 min to 24 hours. It was concluded that VF filaments evaluation showed that pre-emptive epidural morphine produced more effective and lasting postincisional analgesia than ketamine.

Utilizaram-se 14 cães mestiços, com idade inferior a cinco anos e peso médio de 12,5kg, com o objetivo de se avaliar os efeitos da injeção epidural de morfina ou cetamina sobre a dor pós-operatória. Os cães foram anestesiados com sevoflurano por meio de máscara facial, e em ato contínuo, receberam injeção epidural de morfina (0,1mg/kg; G1) ou cetamina (0,2mg/kg; G2) diluídas em 0,3ml/kg de solução salina. A incisão experimental de 1,5cm foi realizada no coxim plantar e suturada com fio de náilon. Interrompida a anestesia inalatória e decorridos 30 minutos iniciou-se a avaliação da dor peri-incisional, aplicando-se os filamentos de von Frey a 0,3cm equidistantes da incisão. O procedimento foi repetido a intervalos de 30 minutos até 120 minutos, e posteriormente às 3, 4, 5, 6 e 24 horas do período pós-incisional. Os animais de G1 não responderam à estimulação com os filamentos e apoiaram o membro incindido normalmente durante todo o período de avaliação. No G2 observou-se aumento progressivo da resposta à estimulação pelos filamentos de von Frey desde os 90 minutos até 24 horas. A morfina reduziu a dor pós-incisional por 24 horas, mostrando-se mais efetiva do que a cetamina para o controle da dor.