The effect of epidurally administered dexamethasone with lignocaine for post-operative analgesia in dogs undergoing ovariohysterectomy. A dose-response study

Abstract Purpose: To evaluate the postoperative analgesic and adverse effects of three doses of dexamethasone, administered epidurally in combination with lignocaine, in dogs undergoing ovariohysterectomy (OVH). Methods: Twenty-four female dogs undergoing ovariohysterectomy were pre-medicated with acepromazine and general anaesthesia was induced and maintained with propofol. Animals were randomly allocated into four groups of six. The control group was given lignocaine 2% (LI) and the treatment groups were given lignocaine with either 2 mg dexamethasone (LIDEX2), 4 mg dexamethasone (LIDEX4) or 8 mg dexamethasone (LIDEX8) administered at the lumbosacral epidural space. Duration of postoperative analgesia, first analgesic rescue, motor blockade, heart rate, blood pressure, respiratory rate, and rectal temperature were evaluated. Results: The duration of postoperative analgesia was 19.5 (SD 6) hours for LIDEX8 (p=0.001), 10 (SD 2) hours for LIDEX4 (p=0.002), 4 (SD 2) hours for LIDEX2 (p=0.074) treatments compared with values for the LI control treatment 2.2 (SD 1.6) hours. All treatments had significant cardiovascular and respiratory alterations but they were within acceptable range in these clinically healthy female dogs. Conclusion: Dexamethasone added to epidural lignocaine significantly extends the postoperative analgesia after ovariohysterectomy in female dogs.

Dexmedetomidina epidural em gatas submetidas à ovariosalpingohisterectomia sob anestesia total intravenosa com propofol e pré-medicadas com cetamina S(+) e midazolam / Epidural dexmedetomidine in cats submitted to ovariosalpingohisterectomy under intravenous total anesthesia with propofol and pre medicated with ketamine (S) and midazolam

O objetivo deste estudo foi avaliar os efeitos da administração epidural de dexmedetomidina em gatas submetidas à ovariosalpingohisterectomia (OSH), sob infusão contínua de propofol. Para tanto, foram utilizadas 12 gatas adultas, hígidas, com peso médio de 3,3±0,4kg, e entre um e quatro anos de idade. Como medicação pré-anestésica, os animais receberam cetamina S(+) (5mg kg-1) e midazolam(0,5mg kg-1), pela via intramuscular, e propofol como agente indutor (4mg kg-1), pela via intravenosa. Em seguida, os animais foram intubados para receber oxigênio a 100 por cento , por meio de sistema sem reinalação de gases, e a infusão contínua de propofol (0,3mg kg-1 min-1) foi iniciada. Os animais foram alocados em dois grupos, nos quais foram administrados dexmedetomidina (2µg kg-1) por via epidural (GDEX, n=06) e, no grupo controle (GSAL, n=06), solução salina 0,9 por cento pela mesma via. O volume total da solução para administração epidural foi completado com solução salina e ajustado para 0,26ml kg-1 em ambos os grupos. No GSAL, houve necessidade de administração de fentanil imediatamente após o início da cirurgia (T10) em 33,33 por cento dos pacientes. Durante a infusão contínua de propofol, o reflexo palpebral medial esteve presente em 66,6 por cento dos animais do GSAL e em 16,6 por cento dos animais do GDEX. O globo ocular permaneceu centralizado em todos os animais do GSAL e rotacionado em 83,4 por cento dos animais do GDEX. Foi observada redução da freqüência cardíaca após a indução anestésica em ambos os grupos. A pressão arterial média foi menor no T0 e no T5, no GDEX, e maior no T10, no GSAL, em relação ao basal. A freqüência respiratória foi menor no GDEX nos tempos T20 e T30 em relação a GSAL. A SaO2 e a PaO2 foram maiores de T5 até T40 para ambos os grupos em comparação ao basal. Para a PaCO2, foram observados valores maiores de T5 até T40 para o GDEX e maiores no T5, T10 e T20, no GSAL, em relação aos valores basais. Na recuperação...

The objective of this study was to evaluate the effect of the epidural administration of dexmedetomidine in cats submitted to ovariohisterectomy, under continuous infusion of propofol. The cats received S(+) ketamine (5mg kg-1) and midazolan (0.5mg kg-1) as premedication by intramuscular injection, and propofol as induction agent (4mg kg-1), by intravenous injection. After that, the cats were intubated and kept on oxygen 100 percent. Subsequently the continuous infusion of propofol was initiated (0.3mg kg-1 min-1). The animals were divided into two groups, in the dexmedetomidine group (DEXG, n=6,2µg kg-1) dexmedetomidine was administered by epidural injection, and in the control group (SALG, n=6) saline solution was administered by the same way. In both groups the final volume was 0.26 mL kg-1 completed with NaCl 0.9 percent. Fentanyl administration was necessary at T10 in 33.3 percent of the patients. During the continuous infusion of propofol, the medial palpebral reflex was present in 66.6 percent of the animals of SALG and in 16.6 percent of the animals of DEXG. The eyeball was centralized in all the animals of SALG and 83.4 percent of the animals of DEXG the eyeball were with ventral rotation. Reduction of the heart rate was observed after anesthesia induction in both groups. The mean arterial pressure was significantly lesser at T0 and T5 in the DEXG and greater at T10 in the SALG when compared to the basal values. The respiratory rate was lesser in the DEXG at T20 and T30 when compared to SALG. The SaO2 and PaO2 were bigger from T5 to T40. The PaCO2 bigger values were observed at T5, T10, T20, T30 and T40 for the DEXG and at T5, T10 and T20 in the SALG when compared to the basal values. In the anesthetic recovery, 50 percent and 16.6 percent of the animals presented aggressiveness in the SALG and DEXG, respectively. To the wound pain threshold, it was observed that 33.3 percent of animals of SALG and 66.7 percent of the animals...

Injeção epidural preventiva de xilazina ou amitraz em eqüinos: efeitos clínicos e comportamentais / Pre-emptive epidural injection of xylazine or amitraz, in horses: clinical and behavioral effects

A xilazina é o fármaco agonista adrenérgico α2 mais utilizado pela via epidural de eqüinos e sabe-se que o amitraz tem ação sobre esses receptores. Assim, foram avaliados os efeitos clínicos e comportamentais causados pela injeção epidural de 0,17mg kg-1 de xilazina (GX) ou de 0,1mg kg-1 de amitraz diluído em emulsão lipídica (GA) durante 24 horas, em doze eqüinos. A freqüência cardíaca e a altura de cabeça mantiveram-se inalteradas; a freqüência respiratória aumentou de T105 a T360 no GX; a temperatura retal elevou-se de T120 a T720 em GA e de T360 a T720 em GX. Não houve diferença no tempo de latência para urinar ou defecar em ambos os grupos. Em relação às alterações comportamentais, o amitraz provocou sedação (50 por cento), ptose labial (33,4 por cento) e palpebral (16,7 por cento), enquanto que a xilazina promoveu ataxia (50 por cento), sudorese perineal (33,4 por cento), ptose palpebral (16,6 por cento) e relaxamento do esfíncter anal (16,6 por cento). Considera-se segura a injeção epidural de xilazina ou amitraz em eqüinos, pois as alterações clínicas e comportamentais promovidas são leves e não limitam seu uso.

Xylazine is the α2-adrenergic agonist more employed by epidural route in horses and it is known that amitraz acts on these receptors. So, clinical and behavioral effects caused by epidural injection of 0.17mg kg-1 xylazine (GX) or 0.1mg.kg-1 amitraz diluted in lipidic emulsion (GA) were evaluated in 12 horses. Heart rate and height of the head didn't change; respiratory rate increased from T105 to T360 in GX; rectal temperature increased from T120 to T720 in GA and from T360 to T720 in GX. There is no difference in latency to urine or defecate in both groups. Concerning behavioral changes, amitraz promoted sedation (50 percent), lip (33.4 percent) and eye (16.6 percent) dropping, while xylazine caused ataxia (50 percent), perineal sweating (33.4 percent), eye dropping (16.6 percent) and anal sphincter relaxation (16.6 percent). So, epidural injection of xylazine or amitraz was considered safe because the clinical and behavioral changes observed are subtle and don't limit its application.

Ropivacaína isolada e associada ao fentanil ou ao tramadol administrados pela via peridural em cães / Ropivacaine individually and in combination with fentanyl or tramadol, administered by peridural via in dogs

A anestesia peridural é amplamente difundida no meio veterinário, utilizando-se o anestésico local isolado ou associado aos opióides, capazes de promover aumento do efeito analgésico. O objetivo deste estudo foi avaliar a função cardiorrespiratória e analgésica da ropivacaína isolada ou associada ao fentanil ou tramadol. Para tanto, oito cães foram tranqüilizados com acepromazina, submetidos à anestesia peridural com um dos seguintes protocolos: GR (ropivacaína), GRF (ropivacaína + fentanil), GRT (ropivacaína + tramadol), em volume total de 0,25ml kg-1, e foram avaliados os parâmetros: freqüência cardíaca e respiratória, temperatura retal, pressão arterial sistólica, e gasometria do sangue arterial, os bloqueios sensitivo e motor, o grau de sedação e a ocorrência de possíveis efeitos indesejáveis. A diminuição da freqüência cardíaca nos grupos GRF e GRT foi mais intensa e ocorreu hipotermia significativa no GRF. Foi evidenciada sedação severa em GRF e GRT. O período de recuperação foi mais curto nos animais de GRT. O GRT foi o grupo que apresentou bloqueio mais cranial. Foram observadas bradicardia, hipotermia e síndrome de Shiff-Sherrington no período trans-anestésico em animais de todos os grupos. Nas 24 horas de período pós-anestésico, não foram evidenciados efeitos indesejáveis nos grupos. O GRF apresentou maior duração de anestesia e analgesia, enquanto que o GRT apresentou a menor duração de anestesia com analgesia intermediária e o GR apresentou duração intermediária, com menor analgesia. Não foram encontradas alterações respiratórias e hemogasométricas, porém, bradicardia, hipotermia e síndrome de Schiff-Sherrington, alterações trans-anestésicas comuns na anestesia peridural foram encontradas.

Peridural anesthesia is broadly applied in the Veterinary field, using the isolated local anesthetic or in combination with opiates capable to increase the analgesic effect. This research compared analgesia and cardiorespiratory effects of epidural anaesthesia produced by ropivacaine alone or combined with fentanyl or tramadol in eight mixed breed adult dogs after sedation with acepromazina. Drugs were administered on the following protocols: GR (ropivacaine), GRF (ropivacaine + fentanyl), GRT (ropivacaine + tramadol), in 0.25ml kg-1 of total volume. Heart and respiratory rate, rectal temperature, blood pressure and, gasometry of atrial blood were mensured, as well the sensory and motor blockade (latency and period of action), degree of sedation and side effects. The most important decrease of the heart rate occurred in GRF and GRT. Also significant hypothermia in GRF. Intense degree of sedation was observed in GRF and GRT. The period of recovery was shorter in GRT. The most cranial region of blockade occurred in GRT. Bradicardia, hypothermia and Shiff-Sherrington syndrom were observed in the transanesthetic period in animal from all of the groups. During 24 hours after the anaesthesia no side effects were observed. The GRF had the longer period of anesthesia and analgesia, GRT presented the shorter period of anesthesia with intermediate analgesia and, GR presented intermediate period of anesthesia with lower degree of analgesia. Respiratory and hemogasometrics change were not found, but hipotermy, bradicardy and Schiff-Sherrington syndrome, side effects usually seen in peridural anesthesia, were observed in this study.

Analgesic effect of caudal epidural ketamine in cattle

This study was performed to clarify the analgesic effect of ketamine injected into the first intercoccygeal (Co1-Co2) epidural space in standing cattle. Five adult cows were randomly received 3 treatments at least 1 week interval: 5, 10 and 20 mL of 5% ketamine. Sedation, analgesia, ataxia and other effects on cardiopulmonary and rumen functions were assessed before ketamine administration and until 120 min. The analgesia without sedation was shown at tail and perineum about 5 min after all three treatments. The duration of analgesia was significantly increased according to the volume of ketamine (p < 0.01). There was a similar tendency of ataxia with individual variation. There were minimal effects on cardiopulmonary and rumen functions. The present study showed that caudal epidural ketamine administration induced analgesia without sedation in cows, and the duration of analgesia was dose dependent with ataxia. However, the duration of analgesia after 5 and 10 mL ketamine administration is short for common surgical procedures and pain relief of perineum. Further studies are needed to prolong the duration of analgesia without side effects.

Epidural xylazine analgesia in some domesticated animals

Caudal epidural analgesia was successfully conducted in domesticated animals using xylazine hydrochloride in a dose of 0.1 -0.15 mg/kg body weight. It provided good analgesia, posterior muscle slackening and variable degree of surgical interferences and obstetrical manipulations in the posterior regions were performed under the influence of caudal epidural xylazine analgesis. Clinical manifestations were fully described and no complications were observed