Epidural anesthesia with ropivacaine with or without clonidine and postoperative pain in hemorrhoidectomies

To determine the safety, pain intensity correlated with age and body mass index (BMI), epidural anesthesia with ropivacaine and clonidine in hemorrhoidectomy. METHODS: Eighty patients, both genders, 20-70 years old, ASA I or II, for hemorrhoidectomy were randomly divided into two groups: Control (n=38), epidural anesthesia with 14 mL of ropivacaine 0.75 % plus 0.0266 mL/kg of 0.9% saline solution; Experimental (n=42) epidural anesthesia with 14 mL of 0.75% ropivacaine plus 4.0 mcg/kg of clonidine. In preoperative and postoperative period were evaluated: systolic blood pressure (SBP), diastolic blood pressure (DBP ), heart rate (HR ), pulse oximetry (SpO2), electrocardiography (ECG), pain intensity (VAS ) in four, eight and, 12 hours and analgesic consumption. RESULTS: The VAS values differed between four, eight and 12 hours in the Experimental Group, where correlation of VAS 12h with age (p<0.05) occurred and not with BMI and more patients (p<0.05) did not receive analgesics. SBP, DBP, HR changed similarly in both groups at 15, 30 and 45 min. The ECG and SpO2 remained unchanged. CONCLUSIONS: Clonidine (4mcg/kg) in epidural anesthesia with ropivacaine 0.75% in hemorrhoidectomy showed safety and greater analgesia within four hours. The pain at 12 hours showed correlation with age and not with body mass index.(AU)

Spinal anesthesia for elective ceasarean section: use of different doses of hyperbaric bupivacaine associated with morphine and clonidine

PURPOSE: To comparatively study the efficacy and maternal and fetal side-effects of two doses of bupivacaine associated with morphine and clonidine, administered by the subarachnoid route for cesarean section. METHODS: The study included 66 pregnant women at term, distributed into two groups. GI: bupivacaine 8.0 mg (1.6mL) + clonidine 75µg (0.5mL) + morphine 100µg (1.0mL) and GII: bupivacaine 10mg (2.0mL) + clonidine 75µg (0.5mL) + morphine 100µg (1.0mL). The following parameters were assessed: onset and maximum level of sensory block; quality of intraoperative and postoperative analgesia; degree and duration of motor block; maternal repercussions and Apgar score. RESULTS: The onset of sensory block, quality of intraoperative analgesia and total duration of analgesia were similar in both groups; maximum extent of sensory block predominated in T4; maximum degree of motor block (Bromage 3); time motor block regression was significantly longer in GII; Hemodynamic, respiratory repercussions, adverse maternal effects and Apgar scores were similar between groups. In both groups, there was a predominance of drowsy or sleeping patients. CONCLUSION: The addition of morphine and clonidine to low doses of hyperbaric bupivacaine produced adequate anesthesia for cesarean section and good postoperative analgesia, without any maternal and fetal repercussions.(AU)

Participação da via alfa-2 adrenérgica no controle da secreção do hormônio do crescimento no período pré-púbere em novilhas da raça Nelore / Participation of the pathway alfa-2: adrenergic in the control of growth hormone secretion in the pre-puberty period of the Nellore heifers

O objetivo deste trabalho foi investigar a variação na secreção de GH em resposta ao tratamento com clonidina, agonista alfa-2 adrenérgico, no período pré-púbere de novilhas da raça Nelore, e desta forma obter informações neuroendócrinas envolvidas no processo de maturação sexual destes animais. A administração de clonidina (10 µg/kg, I.V., amostras 15 min por 4h) foi feita nas novilhas aos oito (n =4), 12(n = 5) e 15 meses de idade (n = 4). A concentração de GH foi quantificada por radioimunoensaio (sensibilidade = 0,25 ng/mL, CV = 16%). Aos oito meses, a administração do estimulador alfa-2 adrenérgico aumentou a concentração de GH, área total de picos, área total de secreção de GH e amplitude do maior pico e reduziu o tempo para aparecimento de pico (P < 0,05). A administração de clonidina aumentou a concentração de GH aos 15 meses, e aos 12 meses, em intervalos restritos (P < 0,05). O uso da clonidina estimulou a secreção de GH em novilhas Nelore pré-púberes. Este efeito foi mais evidente nas novilhas aos oito meses, comparado aos 12 e 15 meses de idade.(AU)

This study investigated GH secretion after clonidine (alpha-2 adrenergic agonist) treatmentin pre-pubertal Nelore heifers. Clonidine (10mg/kg, IV, 15 min samples for 4h) was administrated in the same Nelore heifers at eight (n = 4), 12 (n = 5) and 15 (n = 4) months of age. The GH concentration was measured by radioimmunoassay (sensivity = 0.25 ng/mL, CV = 16%). At eight months, clonidine increased GH average concentration, total area of peaks, the total area of GH secretion and increased peak amplitude and reduced time to onset of peak (P < 0.05). At 15 months, the administration of clonidine increased the GH average concentration and at 12 months the increased occurred only in restricted intervals (P <0.05). Clonidine injection stimulated GH secretion in prepubertal heifers and this effect was more evident in Nelore heifers at eight months compared to 12 and 15 months of age.(AU)

Analgesia epidural com clonidina ou sufentanil epidural em cadelas submetidas à ovariosalpingohisterectomia sob anestesia geral inalatória / Epidural analgesia with clonidine or sufentanil in dogs submitted to ovariohysterectomy under general anesthesia

Background: Epidural administration of opioids and a2-adrenergic agonists allows the use of smaller doses when administered by other routes, providing analgesia during trans and post-anesthetic periods, reducing side effects and postoperative stress. Sufentanil in higher doses caused minimal hemodynamic changes in dogs. When given epidurally, clonidine produces analgesia without motor block by a non-opioid mechanism of action. The aim of this study was to evaluate the quality and duration of analgesia as well the cardiorespiratory changes resulting from administration of epidural clonidine or sufentanil in dogs anesthetized with halothane. Materials, Methods & Results: Twenty adult health dogs were used divided into two groups, clonidine (CLO) group and sufentanil (SUF) receiving 150 µg and 50 µg respectively epidural. After induction with thiopental and propofol in a mixture of equal parts (0.8 mg/kg), general anesthesia was maintained with halothane in a Bain circuit for further epidural administration of drugs. Heart rate and cardiac rhythm, respiratory rate, tidal volume, min volume, systolic arterial pressure, body temperature, oxygen saturation of oxyhemoglobin, halothane vaporization were evaluated at times T0 (baseline) and every 15 min until the end of the procedure (T1, T2, T3, T4). The arterial blood gas analysis was performed at T0G (baseline) and 30 min and 2 h after epidural (T1G, T2G) evaluating pH, PaO2 , PaCO2 , BE, HCO3 - and TCO2 . Postoperative analgesia was assessed by the scale of Firth & Haldane (1999) every hour for five hours, starting one hour after the surgery. All parametric variables were analyzed by use of a 1-way ANOVA for repeated measures, followed by a Dunnet test to compare all sample collection times with baseline data (0 min). For comparisons among groups, for each time, test t was used. Differences were considered significant when P < 0.05. The results showed a significant reduction in heart rate after 15 min lasting for 60 min with a reduction in SAP, but no signs of hypotension. A reduction in respiratory rate was also observed in the SUF group and vaporization of halothane in both groups with increase in SpO2 . There was no difference in cardiac rhythm and tidal volume, there was only an increase in minute volume at 60 min in the SUF group. Body temperature also decreases at all times. Discussion: The reduction in heart rate was observed since sufentanil have discrete sympatholytic and vagotonic activity and a2-adrenergic agonists may also cause bradycardia by vagomimetic effect. The drugs used can also cause a reduction in blood pressure, but hypotension was not observed in this study, corroborating with several authors. The lipophilic opioids suffer greater absorption by the blood vessels in the epidural region resulting in peak plasma concentration and early respiratory depression, while the a2-adrenergic agonists cause respiratory depression secondary to central nervous system depression. The observed reduction in vaporization is due to potentiation of drugs used. Analgesia in the intraoperative period can be proved since tachycardia, tachypnea, or hypertension during clamping of the ovarian pedicles was not observed and in the immediate postoperative period, both drugs proved effective with Firth & Haldane numerical scale. The doses employed by epidural reduced the need for halothane demonstrating intra-operative analgesic effect. Furthermore, sufentanil caused severe respiratory depression, however it is suggested greater efficacy when compared to clonidine in the immediate postoperative period.(AU)

Analgesia epidural com clonidina ou sufentanil epidural em cadelas submetidas à ovariosalpingohisterectomia sob anestesia geral inalatória / Epidural analgesia with clonidine or sufentanil in dogs submitted to ovariohysterectomy under general anesthesia

Background: Epidural administration of opioids and a2-adrenergic agonists allows the use of smaller doses when administered by other routes, providing analgesia during trans and post-anesthetic periods, reducing side effects and postoperative stress. Sufentanil in higher doses caused minimal hemodynamic changes in dogs. When given epidurally, clonidine produces analgesia without motor block by a non-opioid mechanism of action. The aim of this study was to evaluate the quality and duration of analgesia as well the cardiorespiratory changes resulting from administration of epidural clonidine or sufentanil in dogs anesthetized with halothane. Materials, Methods & Results: Twenty adult health dogs were used divided into two groups, clonidine (CLO) group and sufentanil (SUF) receiving 150 µg and 50 µg respectively epidural. After induction with thiopental and propofol in a mixture of equal parts (0.8 mg/kg), general anesthesia was maintained with halothane in a Bain circuit for further epidural administration of drugs. Heart rate and cardiac rhythm, respiratory rate, tidal volume, min volume, systolic arterial pressure, body temperature, oxygen saturation of oxyhemoglobin, halothane vaporization were evaluated at times T0 (baseline) and every 15 min until the end of the procedure (T1, T2, T3, T4). The arterial blood gas analysis was performed at T0G (baseline) and 30 min and 2 h after epidural (T1G, T2G) evaluating pH, PaO2 , PaCO2 , BE, HCO3 - and TCO2 . Postoperative analgesia was assessed by the scale of Firth & Haldane (1999) every hour for five hours, starting one hour after the surgery. All parametric variables were analyzed by use of a 1-way ANOVA for repeated measures, followed by a Dunnet test to compare all sample collection times with baseline data (0 min). For comparisons among groups, for each time, test t was used. Differences were considered significant when P < 0.05. The results showed a significant reduction in heart rate after 15 min lasting for 60 min with a reduction in SAP, but no signs of hypotension. A reduction in respiratory rate was also observed in the SUF group and vaporization of halothane in both groups with increase in SpO2 . There was no difference in cardiac rhythm and tidal volume, there was only an increase in minute volume at 60 min in the SUF group. Body temperature also decreases at all times. Discussion: The reduction in heart rate was observed since sufentanil have discrete sympatholytic and vagotonic activity and a2-adrenergic agonists may also cause bradycardia by vagomimetic effect. The drugs used can also cause a reduction in blood pressure, but hypotension was not observed in this study, corroborating with several authors. The lipophilic opioids suffer greater absorption by the blood vessels in the epidural region resulting in peak plasma concentration and early respiratory depression, while the a2-adrenergic agonists cause respiratory depression secondary to central nervous system depression. The observed reduction in vaporization is due to potentiation of drugs used. Analgesia in the intraoperative period can be proved since tachycardia, tachypnea, or hypertension during clamping of the ovarian pedicles was not observed and in the immediate postoperative period, both drugs proved effective with Firth & Haldane numerical scale. The doses employed by epidural reduced the need for halothane demonstrating intra-operative analgesic effect. Furthermore, sufentanil caused severe respiratory depression, however it is suggested greater efficacy when compared to clonidine in the immediate postoperative period.

Efeitos comportamental, clínico e analgésico promovidos pela injeção epidural preventiva de morfina, xilazina ou clonidina, em equinos

Opioids and 2-agonists have analgesic effect and preventive administration by epidural route can minimize undesirable and clinical effects. So, behavioral, clinical and analgesic effects were evaluated for 24 hours after preventive epidural injection of morphine (0,1mg kg-1), xylazine (0,17mg kg-1) or clonidine (3µg kg-1) in 18 horses subjected to incisional model of inflammatory pain evaluated by von Frey filaments. Behavioral changes and changes in heart rate, respiratory rate, rectal temperature and height of head were minimum and transitory. Cutaneous sensivity in injured skin was similar to complete skin for 24, 8 and 12 hours after preventive epidural injection of morphine, xylazine and clonidine, respectively. Moreover, clinical and behavioral changes were not severe along 24 hours.

Os agonistas dos receptores adrenérgicos 2 e os opioides tem ação analgésica e a aplicação preventiva pela via epidural pode minimizar os efeitos clínicos e comportamentais indesejáveis. Assim, avaliaram-se os efeitos comportamental, clínico e analgésico promovidos pela injeção epidural preventiva de morfina (0,1mg kg-1), xilazina (0,17mg kg-1) ou clonidina (3µg kg-1) durante 24 horas, em 18 equinos submetidos a um modelo incisional de dor inflamatória e avaliados pelos filamentos de von Frey. As alterações comportamentais, de frequência cardíaca, frequência respiratória, temperatura retal e altura de cabeça em relação ao solo foram mínimas e transitórias. A sensibilidade cutânea em pele incisada foi semelhante à sensibilidade da pele íntegra por 24, 8 e 12 horas após a administração epidural preventiva de morfina, xilazina ou clonidina, respectivamente, em equinos submetidos ao modelo incisional de dor inflamatória e avaliados com filamentos de von Frey. Além disso, não ocorreram alterações clínicas ou comportamentais importantes ao longo de 24 horas.

Efeitos comportamental, clínico e analgésico promovidos pela injeção epidural preventiva de morfina, xilazina ou clonidina, em equinos

Opioids and 2-agonists have analgesic effect and preventive administration by epidural route can minimize undesirable and clinical effects. So, behavioral, clinical and analgesic effects were evaluated for 24 hours after preventive epidural injection of morphine (0,1mg kg-1), xylazine (0,17mg kg-1) or clonidine (3µg kg-1) in 18 horses subjected to incisional model of inflammatory pain evaluated by von Frey filaments. Behavioral changes and changes in heart rate, respiratory rate, rectal temperature and height of head were minimum and transitory. Cutaneous sensivity in injured skin was similar to complete skin for 24, 8 and 12 hours after preventive epidural injection of morphine, xylazine and clonidine, respectively. Moreover, clinical and behavioral changes were not severe along 24 hours.

Os agonistas dos receptores adrenérgicos 2 e os opioides tem ação analgésica e a aplicação preventiva pela via epidural pode minimizar os efeitos clínicos e comportamentais indesejáveis. Assim, avaliaram-se os efeitos comportamental, clínico e analgésico promovidos pela injeção epidural preventiva de morfina (0,1mg kg-1), xilazina (0,17mg kg-1) ou clonidina (3µg kg-1) durante 24 horas, em 18 equinos submetidos a um modelo incisional de dor inflamatória e avaliados pelos filamentos de von Frey. As alterações comportamentais, de frequência cardíaca, frequência respiratória, temperatura retal e altura de cabeça em relação ao solo foram mínimas e transitórias. A sensibilidade cutânea em pele incisada foi semelhante à sensibilidade da pele íntegra por 24, 8 e 12 horas após a administração epidural preventiva de morfina, xilazina ou clonidina, respectivamente, em equinos submetidos ao modelo incisional de dor inflamatória e avaliados com filamentos de von Frey. Além disso, não ocorreram alterações clínicas ou comportamentais importantes ao longo de 24 horas.

Efeito sedativo e alterações fisiológicas da administração de clonidina por via intramuscular em cães intramuscular em cães / Physiologic alterations and sedative effect of intramuscular administration of clonidine in dogs

Background: α2-adrenergic agonists stand out for their intense acting in the respiratory and hemodynamic parameters, which sometimes aggravates the already compromised patient. Clonidine is widely used in humans due to its sedation, minimal hemodynamic and respiratory changes and for analgesia. In veterinary medicine, clonidine has been studied recently specially for epidural analgesia. The study aimed to evaluate the physiological changes and the sedative effect of the intramuscular administration of clonidine in dogs, once there are no reports of intramuscularly use of clonidine. Materials, Methods & Results: Six adult healthy mongrel dogs (5 females and 1 male) were used, after hematological evaluation (complete hemogram) with an average weight of 12 ± 2.5 kg. The animals were randomly divided into four groups with a minimum interval of 10 days, where: control group (GC) received 5 mL of saline IM with the other three groups receiving different doses of clonidine, 5 µg/kg (CLO5), 15 ìg/kg (CLO15) and 30 µg/kg (CLO30) intramuscularly. Heart and respiratory rate, oxygen saturation, systolic arterial pressure, rectal temperature and sedation by analogical descriptive scale were evaluated before administration (baseline), after 5 and 15 min and at 15 min intervals for a period of 90 min. For each group, all parametric variables were analyzed by use of a 1-way ANOVA for repeated measures, followed by a Dunnet test to compare all sample collection times with baseline data (0 min). For comparisons among groups, for each time, 1-way ANOVA was performed, followed by a Tukey test. Score sedation non parametrical variable were analyzed by Friedman test, followed by Dunn’s. Differences were considered significant at P < 0.05. The results showed that clonidine caused a reduction in heart rate 5 min after administration lasting for 90 min with the three doses studied, with a reduction in systolic arterial pressure but with no signs of hypotension. There were respiratory reduction, but between normal values and decreased rectal temperature was observed, with no changes in oxygen saturation. Sedation scores were higher with the higher doses of clonidine. Discussion: The cardiovascular and respiratory effects of administration of α2-adrenergic agonists are characteristic, noting reduction in heart rate which is due mostly to decrease in sympathetic nervous system tonus, which was observed in all treated groups where a significant reduction in heart rate in a gradual manner and tending to be dose dependent since lower values were observed with higher doses, reaching bradycardia (HR <60 bpm) in group CLO30. Another common alteration of α2- adrenergic agonists are the changes in blood pressure, such as hypertension and subsequent hypotension and respiratory depression, frames not observed in this study. Reduction in body temperature is especially due to decrease in muscular activity as well interfering with thermoregulatory mechanisms. Another factor that may contribute is the room temperature, which remained close to 25o C. Intramuscular administration of clonidine caused light and mild sedation with the studies doses and cardiorrespiratory changes should be used in healthy animals. Further studies should be conducted with associations of other pharmacological class to promote a more pronounced level of sedation.

Efeito sedativo e alterações fisiológicas da administração de clonidina por via intramuscular em cães intramuscular em cães / Physiologic alterations and sedative effect of intramuscular administration of clonidine in dogs

Background: α2-adrenergic agonists stand out for their intense acting in the respiratory and hemodynamic parameters, which sometimes aggravates the already compromised patient. Clonidine is widely used in humans due to its sedation, minimal hemodynamic and respiratory changes and for analgesia. In veterinary medicine, clonidine has been studied recently specially for epidural analgesia. The study aimed to evaluate the physiological changes and the sedative effect of the intramuscular administration of clonidine in dogs, once there are no reports of intramuscularly use of clonidine. Materials, Methods & Results: Six adult healthy mongrel dogs (5 females and 1 male) were used, after hematological evaluation (complete hemogram) with an average weight of 12 ± 2.5 kg. The animals were randomly divided into four groups with a minimum interval of 10 days, where: control group (GC) received 5 mL of saline IM with the other three groups receiving different doses of clonidine, 5 µg/kg (CLO5), 15 ìg/kg (CLO15) and 30 µg/kg (CLO30) intramuscularly. Heart and respiratory rate, oxygen saturation, systolic arterial pressure, rectal temperature and sedation by analogical descriptive scale were evaluated before administration (baseline), after 5 and 15 min and at 15 min intervals for a period of 90 min. For each group, all parametric variables were analyzed by use of a 1-way ANOVA for repeated measures, followed by a Dunnet test to compare all sample collection times with baseline data (0 min). For comparisons among groups, for each time, 1-way ANOVA was performed, followed by a Tukey test. Score sedation non parametrical variable were analyzed by Friedman test, followed by Dunns. Differences were considered significant at P < 0.05. The results showed that clonidine caused a reduction in heart rate 5 min after administration lasting for 90 min with the three doses studied, with a reduction in systolic arterial pressure but with no signs of hypotension. There were respiratory reduction, but between normal values and decreased rectal temperature was observed, with no changes in oxygen saturation. Sedation scores were higher with the higher doses of clonidine. Discussion: The cardiovascular and respiratory effects of administration of α2-adrenergic agonists are characteristic, noting reduction in heart rate which is due mostly to decrease in sympathetic nervous system tonus, which was observed in all treated groups where a significant reduction in heart rate in a gradual manner and tending to be dose dependent since lower values were observed with higher doses, reaching bradycardia (HR <60 bpm) in group CLO30. Another common alteration of α2- adrenergic agonists are the changes in blood pressure, such as hypertension and subsequent hypotension and respiratory depression, frames not observed in this study. Reduction in body temperature is especially due to decrease in muscular activity as well interfering with thermoregulatory mechanisms. Another factor that may contribute is the room temperature, which remained close to 25o C. Intramuscular administration of clonidine caused light and mild sedation with the studies doses and cardiorrespiratory changes should be used in healthy animals. Further studies should be conducted with associations of other pharmacological class to promote a more pronounced level of sedation.(AU)

Epidural anesthesia using a 0, 75 percent ropivacaine and subarachnoid anesthesia with a 0, 5 percent bupivacaine associated or not with clonidine in hemorroidectomies / Anestesia peridural com ropivacaína a 0, 75 por cento e anestesia subaracnóidea com bupivacaína a 0, 5 por cento associadas ou não à clonidina em hemorroidectomias

PURPOSE: To study the safety and efficiency of two anesthetic blockages in hemorroidectomy and the effect of clonidine on analgesia. METHODS: 80 patients were studied, randomly divided into four groups: l (n=19)- peridural with a 0,75 percent ropivacaine; 2 (n=21)-peridural with a 0,75 percent ropivacaine and 150 µg of clonidine; 3 (n=19)- subarachnoid with a 0,5 percent bupivacaine; 4 (n=21)- subarachnoid with a 0,5 percent bupivacaine and 50 µg of clonidine. The intensity of pain was evaluated by the visual analogical scale 8, 12 and 24 hours after surgery. The use of vasoconstrictors on the transoperatory and the amount of analgesics within the 24 hours were registered. RESULTS: The intensity of pain, 8 hours after surgery, was lesser on group 4, and much lesser on group 4 comparing with groups 1 and 2, 12 hours (p=0,022; p=0,001) and 24 hours (p=0,03; p=0,003). The frequency of vasoconstrictors usage on the transoperatory and the analgesics on the post-operatory showed no difference among the groups. There were no anesthetic complications. CONCLUSIONS: The subarachnoid anesthesia with a 0,5 percent bupivacaine with clonidine, showed better analgesia comparing with the peridural anesthesia with a 0,75 percent ropivacaine with or without clonidine, however all were safe and efficient. The clonidine aided on the decreasing of pain when subarachnoid anesthesia was used.(AU)

OBJETIVO: Verificar a segurança e a eficácia de dois bloqueios anestésicos na hemorroidectomia e o efeito da clonidina na analgesia. MÉTODOS: Foram estudados oitenta pacientes, distribuídos aleatoriamente em quatro grupos: 1 (n=19)- peridural com ropivacaína a 0,75 por cento; 2 (n=21)-peridural com ropivacaína a 0,75 por cento e 150 µg de clonidina; 3 (n=19)-subaranóidea com bupivacaína a 0,5 por cento; 4 (n=21)- subaracnóidea com bupivacaína a 0,5 por cento e 50 µg de clonidina. A intensidade da dor foi avaliada pela escala analógica visual 8, 12 e 24 horas após a cirurgia. O uso de vasoconstritores no transoperatório, o consumo de analgésicos em 24 horas foram anotados. RESULTADOS: A intensidade da dor, 8 horas após a cirurgia, foi menor no grupo 4, e significantemente menor no grupo 4 em relação aos grupos 1 e 2, 12 horas (p=0,022; p=0,001) e 24 horas (p=0,03; p=0,003). A freqüência do uso de vasoconstritores no transoperatório e de analgésicos no pós-operatório não diferiu entre os grupos. Não houve complicações anestésicas. CONCLUSÕES: A anestesia subaracnóidea com bupivacaína a 0,5 por cento, com clonidina, apresentou melhor analgesia que a anestesia peridural com ropivacaína a 0,75 por cento com ou sem clonidina, porém todas foram seguras e eficazes. A clonidina contribuiu para diminuir a dor na anestesia subracnóidea.(AU)

Analgesia epidural com clonidina ou romifidina em cães submetidos à cirurgia coxofemoral / Epidural analgesia with clonidine or romifidine in dogs submitted to coxofemoral surgery

Avaliaram-se as alterações cardiorrespiratórias e a analgesia da administração epidural de clonidina ou romifidina em cães submetidos à cirurgia coxofemural. Foram utilizados 14 cães distribuídos em dois grupos: o grupo Cloni recebeu 150µg de clonidina e o grupo Romi, 20µg/kg de romifidina. A indução anestésica foi realizada com propofol e a anestesia cirúrgica mantida com halotano e O2 em respiração espontânea. A punção do espaço epidural foi feita logo após a indução. Antes da indução e a cada 10 minutos foram avaliadas as freqüências cardíaca e respiratória, a pressão arterial sistólica, a saturação de oxigênio da hemoglobina e a concentração de halotano. Após indução e ao término do procedimento cirúrgico coletou-se sangue arterial para avaliação gasométrica de pH, PaCO2, PaO2, SaO2, BE e HCO3-. Foi realizada avaliação pós-operatória do grau de analgesia (intensa, pouco intensa e inadequada) nas primeiras duas horas após término da cirurgia. Os animais do grupo Romi apresentaram bradicardia, bradiarritmias e hipertensão. A freqüência cardíaca e a pressão arterial sistólica no grupo Cloni mantiveram-se dentro da faixa de variação fisiológica para a espécie. A analgesia trans-operatória foi considerada intensa nos dois grupos. A administração epidural de clonidina ou romifidina produziu intensa analgesia transcirúrgica sem depressão respiratória e pouco intensa analgesia pós-operatória por duas horas. (AU)

Cardiovascular alterations and analgesia in 14 dogs submitted to epidural administration of clonidine or romifidine to enable coxofemoral surgery were evaluated. Dogs were separated in two groups: Cloni group received 150µg of clonidine and Romi group, 20µg/kg of romifidine. Anesthetic induction was performed using propofol (8mg/kg) and maintenance using halothane and O2 in spontaneous breathing. The puncture of epidural space was performed just after anesthetic induction. Heart rate and respiratory rate, systolic arterial rate, hemoglobin oxygen saturation and halothane concentration were assessed before anesthetic induction, and at each 10 minutes until the end of the surgery. Samples of arterial blood were collected after anesthesic induction and at the end of the surgical procedure in order to assess pH, PaCO2, PaO2, SaO2, BE and HCO3- levels. The analgesia degree (intense, middle or inadequated) was evaluated for two postoperative hours. Numerical data were analysed with ANOVA and Bonferroni's test (P< 0.05). Dogs of Romi group had bradycardia, bradyarrhrytmia, and hypertension. The heart rate and systolic arterial pressure in the Cloni group were within the physiologic variation parameter to dogs. In conclusion epidural administration of clonidine or romifidine produce intense intraoperative analgesia, with no respiratory depression, and middle analgesia for two postoperative hours. Bradycardia and hypotension were not observed with epidural clonidine, however, bradyarrhytmia and hypertension ocurred with epidural romifidine.(AU)