Efeitos cardiovasculares da medetomidina e cetamina em Puma concolor e tempo de recuperação após aplicação de ioimbina ou atipamezole / [Cardiovascular effects of medetomidine and cetamine in Puma concolor and recovery time after application of ioimbin or atipamezole]

O objetivo deste estudo foi avaliar as alterações cardiorrespiratórias causadas pela medetomidina associada à cetamina, e o tempo de recuperação após aplicação intramuscular de atipamezole ou ioimbina em Puma concolor. Para isso, foi realizada a aplicação de medetomidina (100µg/kg) associada à cetamina (5mg/kg) em 11 onças-pardas, sendo os parâmetros cardiorrespiratórios registrados a cada 15 minutos, durante 90 minutos de avaliação. Em seguida, a anestesia foi revertida com aplicação intramuscular de ioimbina (0,4mg/kg; n=5) ou atipamezole (0,25mg/kg; n=6), sendo analisado o tempo até a recuperação. Dos parâmetros cardiorrespiratórios avaliados, houve diferença apenas na frequência respiratória (entre os momentos 60 e 90 minutos), estando esta, todavia, dentro do intervalo de referência para a espécie. Além disso, verificou-se tempo para decúbito esternal significativamente menor nos animais do grupo atipamezole (18±7 minutos), quando comparado ao grupo ioimbina (36±17 minutos), entretanto o tempo de recuperação completa foi estatisticamente igual entre os dois reversores analisados. Assim, a associação anestésica promoveu anestesia eficiente, segura e de rápida indução em onças-pardas, permitindo a imobilização dos animais durante os 90 minutos de avaliação, sem a ocorrência de complicações. Ao se comparar a reversão anestésica com atipamezole e ioimbina, observou-se equivalência dos fármacos no tempo de recuperação completa dos animais.(AU)

The aim of this study was to evaluate the cardiorespiratory changes caused by ketamine-associated medetomidine, and the recovery time after intramuscular application of atipamezole or yohimbine in Puma concolor. For this, the application of medetomidine (100µg/kg) associated with ketamine (5mg/kg) was performed in eleven brown ounces, and the cardiorespiratory parameters were recorded every 15 minutes during 90 minutes of evaluation. Afterwards, anesthesia was reversed with intramuscular application of yohimbine (0.4mg/kg; n=5) or atipamezole (0.25mg/kg; n=6), and time to recovery was analyzed. Of the cardiorespiratory parameters evaluated, there was a difference only in respiratory rate (between 60 and 90 minutes), however, within the reference range for the species. In addition, there was a significantly shorter time for sternal decubitus in the animals of the atipamezole group (18±7 minutes) when compared to the yohimbine group (36±17 minutes), however the complete recovery time was statistically equal between the two reversers analyzed. Thus, the anesthetic association promoted efficient, safe and fast induction anesthesia in puma, allowing the animals to be immobilized during the 90 minutes of evaluation without complications. Comparing anesthetic reversal with atipamezole and yohimbine, drug equivalence was observed in the complete recovery time of the animals.(AU)

Colheita farmacológica de sêmen de onças-pardas (Puma concolor: Mammalia: Carnivora: Felidae) / Pharmacological semen collection in cougars (Puma concolor: Mammalia: Carnivora: Felidae)

Objetivou-se, por meio do presente estudo, avaliar o método de colheita farmacológica de sêmen com sondagem uretral, em machos de onças-pardas (Puma concolor) mantidos em cativeiro. A técnica proposta (Cat; N=3) foi comparada com a eletroejaculação (EE; N=4). Para a colheita farmacológica, utilizou-se medetomidina para induzir a liberação de sêmen na uretra e sonda uretral para gatos, sem janela lateral, para colheita do sêmen por capilaridade. O método foi eficaz em todos os animais usados. Por meio dessa técnica, colheram-se amostras com menor volume (106,7±30,5aµL) e maior concentração (524,1±54,3b x 106 espermatozoides/mL) em relação à EE (450,0±0,1bµL e 205,0±141,8a x 106 espermatozoides/mL). As avaliações de vigor, motilidade e patologia espermática demonstraram que a técnica não afeta a qualidade do sêmen em relação à EE (P>0,05). Dessa forma, o método proposto consiste em uma técnica mais prática e eficiente para a colheita de sêmen com boa qualidade, dispensando o eletroejaculador.(AU)

The aim of this study was to evaluate the pharmacological semen collection method with urethral catheterization (CT) in captive cougar (Puma concolor) males. The pharmacological method (CT; N= 3) was compared to the electroejaculation technique (EE; N= 4). For CT collection, medetomidine was administrated to induce semen release using a tomcat catheter inserted into the urethra to collect by capillarity. The proposed method was efficacious on all animals used. Through the CT method, semen collected yielded smaller volume (106,7±30,5aµL) and higher concentration (524,1±54,3b x 106sperm/mL) compared to EE (450,0±0,1bµL and 205,0±141,8a x 106 sperm /mL). Evaluations of vigor, motility and sperm pathology demonstrated that CT does not affect semen quality when compared to EE (P> 0.05). Thus, the proposed method consists of a more practical and efficient technique for semen collection with good quality, eliminating the need for eletroejaculation.(AU)

Medetomidine hydrochloride efficiency and safety in guinea pig (Cavia porcellus), in doses estimated through allometric extrapolation / Eficiência e segurança do cloridrato de medetomidina no cobaio (Cavia porcellus), em doses calculadas por extrapolação alométrica / Eficiencia y seguridad del clorhidrato de medetomidina en cobayo (Cavia porcellus), en dosis calculadas por extrapolación alométrica

In this study, medetomidine hydrochloride, an alfa2 adrenergic receptor agonist, was administered to five adult guinea pigs (three males and two females) to verify the efficiency and safety of using doses calculated by using an allometric scale. A surgical procedure was performed to insert a polyethylene cannula that advanced 2.0 to 2.5 cm into the left carotid artery until the aorta. A minimum recovery period of two days was observed before any other manipulation or pharmacological test were performed. The cannulas were washed every two days with heparinized saline flow and remained patent for two to three weeks after insertion. After surgery, each animal was placed in an open box measuring 45x25x20cm, in a quiet room with soft lighting. The “MS” group received exactly the allometrically calculated dose, while the “2MS” group received twice the allometric dose and the “½ MS” group received half the allometric dose. Parameters were measured and analyzed at 0, 5, 10, 20, 40, 60, 90 and 120 minutes after injection. Body mass was 709.6±169g, 742±172.87g and 710±160.2g for groups 1, 2 and 3, respectively. Body temperature was 101.68±0.19ºF; respiratory rate was 85.2±4.54 strokes per minute; heart rate was 297.13±3.46 beats per minute; PaO2 at 81.7±9.43mmHg; PaCO2 at 34.49±1.59mmHg; pH was measured at 7.41±0.07; hematocrit at 38.4±1.31%; total protein was 4.33±0.29g/dL, glucose was measured at 97.13±3.75mg/dL; systolic blood pressure was 85.53±2.50mmHg; diastolic pressure at 7.,40±3.74mmHg; and mean blood pressure was 78.73±1.13mmHg. Straightening postural reaction was lost at 7.20±2.05, 12.80±3.56 and 8.67±3.06 minutes for groups “2MS, MS and ½ MS”, respectively...

Neste estudo administrou-se cloridrato de medetomidina, um agonista de receptores adrenérgicos alfa2 , a cinco cobaios adultos (três machos e duas fêmeas) para verificar a eficiência e segurança do uso de doses calculadas por meio de extrapolação alométrica. Um procedimento cirúrgico foi realizado para inserir uma cânula de polietileno que avançou 2,0 a 2,5 cm no interior da artéria carótida esquerda, até a aorta. Um período mínimo de recuperação de dois dias foi respeitado antes de qualquer outra manipulação ou teste farmacológico. As cânulas eram lavadas a cada dois dias com fluxo de solução salina heparinizada e permaneceram patentes por duas a três semanas após sua inserção. Após a cirurgia, cada animal foi colocado em uma caixa aberta medindo 45x25x20cm, em uma sala silenciosa com iluminação suave. O grupo “MS” recebeu exatamente a dose alometricamente calculada, enquanto o grupo “2MS” recebeu o dobro da dose alométrica, e o grupo “½ MS” recebeu a metade da dose alométrica. Parâmetros foram mensurados e avaliados aos 0, 5, 10, 20, 40, 60, 90 e 120 minutos após a injeção. A massa corporal foi 709,6±169g, 742±172,87g e 710±160,2g para os grupos 1, 2 e 3 respectivamente, a temperatura corporal foi 101,68±0,19ºF, a frequência respiratória foi 85,2±4,54 movimentos por minuto, a frequência cardía ca foi 297,13±3,46 batimentos per minute, a PaO2 foi 81,7±9,43mmHg, a PaCO2 foi 34,49±1,59mmHg, o pH foi 7,41±0,07, o hematócrito foi 38,4±1,31%, a proteína total foi 4,33±0,29g/dL, a glucose foi 97,13±3,75mg/dL, a pressão sistólica foi 85,53±2,50mmHg, a pressão diastólica foi 71,40±3,74mmHg, e a pressão sanguínea média foi 78,73±1,13mmHg...

En esta investigación se ha administrado clorhidrato de medetomidina, un agonista de receptores adrenérgicos alfa2 , a cinco cobayos adultos (tres machos y dos hembras) para verificar la eficacia y seguridad del uso de dosis calculadas por extrapolación alométrica. Se realizó un procedimiento quirúrgico para introducir una cánula de polietileno penetrando 2,0 a 2,5 cm en la arteria carótida izquierda, hasta la aorta. Se ha respetado un período mínimo de recuperación de dos días antes de cualquier otra manipulación o teste farmacológico. Las cánulas eran lavadas a cada dos días con flujo de solución salina heparinizada, y permanecieron patentes por dos a tres semanas después de la inserción. Después de la cirugía, cada animal fue acomodado en una caja abierta con medida de 45x25x20cm, en una sala silenciosa con iluminación suave. El grupo “MS” recibió exactamente la dosis alométricamente calculada, mientras el grupo “2MS” recibió el doble de la dosis alométrica, y el grupo “½ MS” recibió la mitad de la dosis alométrica. Parámetros fueron mensurados y evaluados a los 0, 5, 10, 20, 40, 60, 90 y 120 minutos después de la inyección. El peso corporal fue 709,6±169g, 742±172,87g y 710±160,2g para los grupos 1, 2 y 3 respectivamente, la temperatura corporal fue 101,68±0,19ºF, la frecuencia respiratoria fue 85,2±4,54 movimientos por minuto, la frecuencia cardíaca fue 297,13±3,46 batimientos por minuto, la PaO2 fue 81,7±9,43mmHg, la PaCO2 fue 34,49±1,59mmHg, el pH fue 7,41±0,07, el hematocrito fue 38,4±1,31%, la proteína total fue 4,33±0,29g/dL, la glucosa fue 97,13±3,75mg/dL, la presión sistólica fue 85,53±2,50mmHg, la presión diastólica fue 71,40±3,74mmHg, y la presión sanguínea promedia fue 78,73±1,13mmHg. La reacción postural de enderezamiento fue perdida en 7.20±2,05, 12,80±3,56 y 8,67±3,06 minutos, para los grupos “2MS, MS y ½ MS”, respectivamente...

Anestesia epidural com associação medetomidina e lidocaína, em gatos pré-medicados com acepromazina e midazolam / Epidural anesthesia with lidocaine and association medetomidine in cats pre-medicated with acepromazine and midazolam

Avaliaram-se os efeitos anestésicos promovidos pela associação medetomidina e lidocaína por via epidural, em gatos pré-tratados com acepromazina e midazolam. Foram utilizados 10 gatos adultos, machos e fêmeas, hígidos e com média de peso de 2,5±0,6kg, distribuídos em dois grupos (GM e GL) de igual número (n=5). Administraram-se, como medicação pré-anestésica, acepromazina, 0,2mg/kg, e midazolam, 0,5mg/kg, via intramuscular, e 20 minutos depois, nos animais do GM, por via epidural, lidocaína, 4,4mg/kg, associada à medetomidina, 0,02mg/kg. Os gatos do GL receberam lidocaína, 4,4mg/kg, associada à solução de NaCl a 0,9 por cento. As avaliações ocorreram antes da pré-anestesia (MPA), 20 minutos após a MPA e antes da anestesia epidural, e aos 10, 20, 30 e 40 minutos após a anestesia epidural, respectivamente, T-20, T0, T10, T20, T30 e T40. Foram avaliados: frequência cardíaca (FC) e respiratória (FR), temperatura do corpo, saturação de oxiemoglobina, analgesia, miorrelaxamento e período de recuperação. No GM, a FC diminuiu em T20, T30 e T40 em relação ao T-20 e T10 e foi mais baixa que a FC do GL em T20, T30 e T40, respectivamente, 86, 91 e 88 bat/min e 194, 205 e 177 bat/min. A FR variou entre o T-20 e os outros momentos de avaliação nos animais do GL. Nas variáveis eletrocardiográficas, houve diferenças entre T20, T30 e T40 e T-20 e T0, valores de 235, 238 e 240ms e 156 e 161ms, respectivamente, somente no GM. Este grupo diferiu do GL nas avaliações em T20, T30 e T40, valores de 147, 132 e 150ms para os gatos do GL. Oitenta por cento dos gatos tiveram analgesia intensa, e em todos os animais ocorreu relaxamento da mandíbula e da língua. O tempo de recuperação foi de 40 e 15min no GM e no GL, respectivamente. Concluiu-se que a associação lidocaína com medetomidina promoveu plano anestésico estável com grau de anestesia e recuperação anestésica de boa qualidade.

The anesthetic effects due to the association of medetomidine and epidural lidocaine in cats pretreated with acepromazine and midazolam were evaluated. Ten adult cats were used, male and female, healthy and weighing 2.5±0.6kg. They were divided into two groups (GM and GL) of equal numbers (n=5). Premedication with acepromazine, 0.2mg/kg, and midazolam, 0.5mg/kg, intramuscular was administered. Twenty minutes later, GM animals were given epidural lidocaine, 4.4mg/kg, associated with medetomidine, 0.02mg/kg. GL cats received lidocaine, 4.4mg/kg, associated with NaCl 0.9 percent. Assessments occurred before the pre-anesthesia (MPA), 20 minutes after premedication and before the epidural block, and 10, 20, 30 and 40 minutes after epidural anesthesia, respectively, T-20, T0, T10, T20, T30 and T40. Heart rate, respiratory rate, body temperature, oxyhemoglobin saturation, analgesia, muscle relaxation and recovery period were evaluated. In GM cats the heart rate decreased at T20, T30 and T40 as compared to T-20 and T10 and was lower than the heart rate in the GL cats at T20, T30 and T40, values being, respectively, 86, 91 and 88 beats/min and 194, 205 and 177 beats/min. The respiratory rate ranged from T-20 and the other time points in GL animals. Concerning electrocardiographic variables, in GM cats significant differences between T20, T30 and T40 and T0 and T-20, were observed, values being 235, 238 and 156 and 161ms and 240ms, respectively. GM animals differed from GL in T20, T30 and T40, values being 147, 132 and 150ms for GL cats. Eighty percent of the cats had severe pain and in all animals there was a relaxation of the jaw and tongue. The recovery time was 40 and 15 min at GM and GL, respectively. It was concluded that the association promoted lidocaine with medetomidine anesthesia with a stable level of anesthesia and anesthetic recovery of good quality.

Hemodynamics and bispectral index (BIS) of dogs anesthetized with midazolam and ketamine associated with medetomidine or dexmedetomidine and submitted to ovariohysterectomy / Avaliação hemodinâmica e do índice bispectral (BIS) de cadelas anestesiadas com midazolam e cetamina associados à medetomidina ou dexmedetomidina e submetidas a ovário-salpingo-histerectomia

Purpose: To evaluate hemodynamics and bispectral index (BIS) in bitches anesthetized with ketamine and midazolam in combination with dexmedetomidine or medetomidine and submitted to ovariohysterectomy. Methods: Twenty bitches pretreated with levomedetomidine and buprenorphine were anesthetized with 5 mg.kg-1 ketamine and 0.2 mg.kg-1 midazolam i.v. Continuous infusion of 0.4 mg.kg-1.h-1 midazolam and 20 mg.kg-1.h-1 ketamine was initiated in combination with DEX (n=10): 20 µg.kg-1.h-1 dexmedetomidine or MED (n=10): 30 µg.kg-1.h-1 medetomidine over 30 minutes. A pharmacokinetic study provided dexmedetomidine plasma concentration, set to be 3.0 ng.mL-1. Results: BIS decreased in both groups (P<0.05), but it was lower in DEX (P<0.05) as compared to MED. No differences were found in hemodynamic parameters (heart rate, systolic, diastolic and mean arterial pressure) between groups (P>0.05), but heart rate decreased in both groups, as compared to control values (P<0.05). Respiratory rate decreased (P<0.05) and expired end tidal CO2 increased progressively (P<0.05) and similarly in both groups. Anesthetic recovery period was similar between groups (P<0.05) with no adverse effects. Conclusion: Continuous administration of dexmedetomidine with calculated plasma concentration equal to 3 ng.mL-1 in combination with midazolam and ketamine provides suitable anesthesia for spay surgery in bitches, hemodynamic stability and calm awakening with no adverse effects.

Objetivo: Verificar o comportamento hemodinâmico e o índice bispectral de cadelas anestesiadas com cetamina e midazolam associados à dexmedetomidina ou medetomidina. Métodos: Vinte cadelas receberam pré-tratamento com levomepromazina e buprenorfina e foram anestesiadas com cetamina, 5 mg.kg-1 i.v., e midazolam, 0,2 mg.kg-1 i.v., seguidos da administração contínua de midazolam, 0,4 mg.kg-1.h-1, e cetamina, 20 mg.kg-1.h-1, associados, conforme o grupo, à: DEX (n=10): dexmedetomidina 20 µg.kg-1.h-1 ou MED (n=10): medetomidina 30 µg.kg-1.h-1, mantidos por 30 minutos. A dose de dexmedetomidina foi obtida por meio de estudo farmacocinético planejando-se concentração plasmática de 3,0 ng.mL-1. Resultados: Os valores do BIS diminuíram em ambos os grupos (P<0,05), mas foram menores no grupo DEX (P<0,05), em comparação com o grupo MED. Não houve diferença significativa nos atributos hemodinâmicos (frequência cardíaca, pressão arterial sistólica, diastólica e média) entre os grupos, mas a frequência cardíaca diminuiu em ambos os grupos em relação ao momento controle (P<0,05). A frequência respiratória diminuiu (P<0,05) e o CO2 expirado aumentou progressivamente em ambos os grupos (P<0,05). O tempo de recuperação anestésica foi semelhante entre os grupos (P>0,05), sem a presença de efeitos adversos. Conclusão: A administração contínua de dexmedetomidina em concentração plasmática calculada de 3 ng.mL-1, em combinação com midazolam e cetamina, resulta em plano anestésico adequado para castração de cadelas, estabilidade hemodinâmica e despertar tranquilo, sem efeitos adversos.

Effect of dexmedetomidine on bispectral index and auditory evoked potential index during anesthesia with target controlled infusion of propofol and remifentanyl / 浙江大学学报·医学版

<p><b>OBJECTIVE</b>To evaluate the effect of dexmedetomidine (Dex) on bispectral index (BIS) and auditory evoked potential index (AAI) during anesthesia with target controlled infusion (TCI) of propofol and remifentanyl.</p><p><b>METHODS</b>Thirty adult patients (ASA I approximate, equalsII) who were scheduled for elective thyroidectomy were monitored with BIS, AAI, ECG, blood pressure, end-tidal CO(2), and pulse oximeter before and during anesthesia. Anesthesia was induced by TCI with propofol 4 mg/L and remifentanyl 1 mu g/kg. After loss of consciousness the patients were intubated after rocuronium 0.6 mg/kg intravenous injection, remifentanyl was then infused at 0.2 microg/(kg x min)(-1) and propofol infusion (Ct) was titrated to maintain a BIS value at 50 +/- 3. At 10 min after stabilization of anesthesia the patients were randomly and double-blindly divided into 2 groups: Group D (n=15) received Dex 0.4 mu g/kg iv administered over 5 min and Group C (n=15) received equal volume of normal saline. Values of BIS, AAI, MAP, HR were recorded every 2 min within 20 min after the administration of the drugs.</p><p><b>RESULTS</b>Before anesthesia the BIS index was 90 +/- 2 in Group D and 92 +/- 2 in Group C, AAI was 81 +/- 1 in Group D and 78 +/- 1 in Group C. In anesthesia with target controlled infusion of propofol, BIS index showed a significant decrease with the i.v. administration of Dex 0.4 microg/kg, while AAI remained unchanged. In Group C, both of BIS and AAI remained unchanged after saline injection.</p><p><b>CONCLUSION</b>During propofol and remifentanyl anesthesia, after the administration of Dex, BIS value demonstrates a predominant decrease, whereas AAI shows no changes.</p>

Evaluation on Efficacy and Safety of Tribromoethanol and Tribromoethanol plus alpha2-Adrenergic Agonists in Different Mouse Strains / 한국실험동물학회지

The present study was carried out to provide a guideline for injecting tribromoethanol (TBE) as the main anesthetic agent, while adjusting the doses of xylazine (X) and medetomidine (M) according to different strains of mice (male ICR, C57BL/6, and BALB/c). Seven intraperitoneal injection anesthesia protocols using TBE and mixtures of TBE and alpha2-adrenergic agonists (TBE/X and TBE/M) were compared in terms of their efficacy and safety (anesthetic duration, death rate, and the development of pathological lesions of abdominal organs). All animals that were injected with a low dose of TBE (200 mg/kg) displayed clear signs of light anesthesia with a strong pedal withdrawal reflex. Despite the good anesthetic effect, a high dose of TBE (400 mg/kg) was not a suitable anesthetic for major surgery in all mouse strains because of the risk of pathologic changes in the abdominal organs, such as retention of the digestive tract, peritonitis, and fibrinoid adhesion. TBE200/X10 and TBE200/M0.5 (TBE, 200 mg/kg; X, 10 mg/kg; M, 0.5 mg/kg) appeared to be safe and provided satisfactory anesthesia in ICR mice. Finally, there were clear differences in anesthetic efficacy among ICR, C57BL/6, and BALB/c strains. TBE/M and TBE/X did not anesthetize BALB/c mice, and it anesthetized C57BL/6 mice for a short time. When administered with TBE/X and TBE/M maintained the sedation of ICR mice. We were able to establish different regimes for each strain (TBE200/X20 for C57BL/6, TBE300/X10 and TBE200/M1 for BALB/c). Our results showed that TBE/X and TBE/M could be recommended as an anesthetic mixture, with the dose appropriately adjusted according to mouse strain.

Evaluation on Efficacy and Safety of Tribromoethanol and Tribromoethanol plus alpha2-Adrenergic Agonists in Different Mouse Strains / 한국실험동물학회지

The present study was carried out to provide a guideline for injecting tribromoethanol (TBE) as the main anesthetic agent, while adjusting the doses of xylazine (X) and medetomidine (M) according to different strains of mice (male ICR, C57BL/6, and BALB/c). Seven intraperitoneal injection anesthesia protocols using TBE and mixtures of TBE and alpha2-adrenergic agonists (TBE/X and TBE/M) were compared in terms of their efficacy and safety (anesthetic duration, death rate, and the development of pathological lesions of abdominal organs). All animals that were injected with a low dose of TBE (200 mg/kg) displayed clear signs of light anesthesia with a strong pedal withdrawal reflex. Despite the good anesthetic effect, a high dose of TBE (400 mg/kg) was not a suitable anesthetic for major surgery in all mouse strains because of the risk of pathologic changes in the abdominal organs, such as retention of the digestive tract, peritonitis, and fibrinoid adhesion. TBE200/X10 and TBE200/M0.5 (TBE, 200 mg/kg; X, 10 mg/kg; M, 0.5 mg/kg) appeared to be safe and provided satisfactory anesthesia in ICR mice. Finally, there were clear differences in anesthetic efficacy among ICR, C57BL/6, and BALB/c strains. TBE/M and TBE/X did not anesthetize BALB/c mice, and it anesthetized C57BL/6 mice for a short time. When administered with TBE/X and TBE/M maintained the sedation of ICR mice. We were able to establish different regimes for each strain (TBE200/X20 for C57BL/6, TBE300/X10 and TBE200/M1 for BALB/c). Our results showed that TBE/X and TBE/M could be recommended as an anesthetic mixture, with the dose appropriately adjusted according to mouse strain.

Anestesia por isofluorano em eqüinos submetidos à infusão contínua de medetomidina ou xilazina / Isoflurane anesthesia in horses during medetomidine or xilazine continuous infusion

Avaliaram-se oito eqüinos sob anestesia geral inalatória com isofluorano (1CAM) e infusão contínua de xilazina (0,35mg kg-1h-1) ou medetomidina (3,5µg kg-1h-1), em relação à freqüência cardíaca, ritmo cardíaco, freqüência respiratória, pressão arterial, hemogasometria arterial e temperatura, nos tempos T0 (imediatamente antes do início da infusão contínua) e T10 ao T60 (intervalos de 10 minutos, após início da infusão contínua). Houve redução da freqüência cardíaca e da temperatura e elevação da pressão arterial média. A paCO2 (no GM) elevou-se e a paO2 mostrou-se maior no GM que no GX. Conclui-se que a infusão contínua de doses equipotentes de xilazina e medetomidina, durante anestesia geral inalatória, com isofluorano, em eqüinos, promove alterações cardiocirculatórias, respiratórias, térmicas e hemogasométricas discretas e equivalentes.

Eight horses under inhalant general anesthesia with isoflurane (1MAC) and continuous infusion of xylazine (0.35mg kg-1h-1) or medetomidine (3.5µg kg-1h-1) were evaluated for heart rate and rhythm, respiratory rate, arterial blood pressure, arterial blood gas analysis and temperature immediately before the beginning of the continuous infusion (T0) and in intervals of 10 minutes after the beginning of the continuous infusion (T10 to T60). Heart rate and temperature decreased and mean arterial pressure increased. PaCO2 (in GM) increased and GM showed a higher paO2 than GX. We conclude that equipotent doses of continuous infusion of medetomidine and xylazine during inhalant general anesthesia with isoflurane in horses promote slight and equivalent cardiocirculatory, respiratory, thermic and arterial blood gases changes.

Continuous infusion in adult females dogs submitted to ovariohysterectomy with midazolam-xylazine and/or medetomidine pre-treated with methotrimeprazine and buprenorphine

PURPOSE: To compare, by continuous infusion of ketamine or medetomidine combined to methotrimeprazine and buprenorphine, ketamine and midazolam, the degree of hypnosis, myorelaxation, anesthetic quality and surgical feasibility through evaluation of possible parametric alterations and recovery quality. METHODS: 20 healthy adult females dogs, aged 3 to 5 years, body weight between 7 and 15 kg, were assigned randomly and homogenously to 2 groups of 10 animals each (n=10), group 1 (G1) and group 2 (G2), respectively. Animals of G1 were subjected to a pre-treatment with intravenous 1.0 mg/kg methotrimeprazine and or 3ì/kg. After 15 minutes, a 5.0 mg/kg ketamine and 0.2 mg/kg midazolam were intravenously injected. Immediately after induction, an anesthetic combination of 0.4 mg/kg/h midazolam, 20 mg/kg/h ketamine and 1.0 mg/kg/h xylazine, was continuously and intravenously administered for 30 minutes. The same techniques were used in G2 except for the substitution of xylazine for 30ìg/kg/h medetomidine. RESULTS: In G1 there was a 1st and 2nd degree atrioventricular heart block, a longer recovery period and lower quality. In G2 a 1st degree atrioventricular heart block occurred but isolated and ephemeral. CONCLUSIONS: The continuous infusion method, besides reducing drugs utilization, prevented collateral effects allowing a more tranquil recovery with no excitations, both protocols permitted the surgical procedure (ovary-hysterectomy) bringing about a reduction in hypnosis and an accentuated myorelaxation. Xylazine and medetomidine showed a similar pharmacodynamic behavior but with different clinical aspects. The electrocardiographic alterations observed in G2 and in a lower degree in G1 must be well studied. Describers: dogs, ketamine, methotrimeprazine, medetomidine, midazolam and xylazine.

OBJETIVO: Comparar através de infusão contínua de xilazina ou medetomidina associada à metotrimeprazina e buprenorfina, cetamina e midazolam, o grau de hipnose, miorrelaxamento e qualidade anestésica e a viabilidade cirúrgica, avaliando eventuais alterações paramétricas e qualidade de recuperação. MÉTODOS: Foram utilizados 20 cães fêmeas, adultas, hígidas (3 a 5 anos de idade) com peso corporal entre 7 e 15 quilos, escolhidas e distribuídas aleatoriamente de forma homogênea em 2 grupos de 10 animais cada, (n=10) sendo estes designados por Grupo 1 (G1), e Grupo 2 (G 2). Em G1, os animais foram submetidos a um pré-tratamento com metotrimeprazina na dose de 1,0 mg/kg e buprenorfina na dose de 0,003mg/kg ou 3 µg/kg intravenoso. Decorridos 15 minutos, administrou-se cetamina na dose de 5,0 mg/kg e midazolam na dose de 0,2 mg/kg intravenoso. Imediatamente após a indução iniciou-se administração contínua, por um período de 30 minutos, da associação anestésica de midazolam 0,4 mg/kg/h, cetamina 20mg/kg/h e xilazina 1,0 mg/kg/h IV. Em G 2 utilizou-se a mesma técnica empregada em G1 substituindo-se, a xilazina pela medetomidina na dose de 30µg/kg/h. RESULTADOS: Verificou-se em G1 bloqueio átrio-ventricular de primeiro e segundo grau, período de recuperação mais longo além de menor qualidade. Em G 2 observou-se bloqueio átrio-ventricular de primeiro grau isolado e de ação fugaz. CONCLUSÕES: Ao se aplicar o método de infusão contínua, além da redução dos fármacos aplicados, evitaram-se efeitos colaterais permitindo uma recuperação mais tranqüila e isenta de excitações, ambos os protocolos permitiram a realização do ato cirúrgico (ovário-salpingo-histerectomia), causando uma redução da hipnose e um miorrelaxamento acentuado. A xilazina e a medetomidina apresentam um comportamento farmacodinâmico semelhante, porém com aspectos clínicos diferentes, as alterações eletrocardiográficas observadas em G 2 e em menor grau em G1 devem ser melhor estudadas.

Efeitos sedativos das associações xilazina/midazolam e medetomidina/midazolan no gato (Felis catus) / Sedative effects of xylazine/midazolam and medetomidine/midazolam in cats

Vinte gatos, machos, sem raça definida, com 1 a 2 anos de idade, hígidos, foram divididos em dois grupos iguais. Em ambos os grupos utilizou-se como medicação pré-anestésica o sulfato de atropina, na dose de 0,03 mg/k, por via intramuscular, 20 minutos antes da administração da associação dos alfa-2 agonistas e do midazolam. O primeiro grupo (x/m) foi submetido à administração intramuscular da associação xilazinal midazolam, nas doses de 1 mg/kg e 0,2 mg/kg e o segundo grupo (m/m) à associação medetomidinal midazolam, nas doses de 0,08 mg/kg, e 0,2 mg/kg, respectivamente. A administração simultânea de alfa-2 agonistas e midazolam induziu a uma rápida e profunda depressão do SNC, que foi mais rápida com a combinação medetomidina/midazolam. O efeito sedativo máximo ocorreu entre 20-30 min. com ambas as combinações. A recuperação foi tranquila sem alterações expressivas.

Twenty healthy tom cats, from 1 to 2 years of age and weighting between 3,5 and 5 kg were used in the study. The animais were divided into two groups and were premedicated with 0,03mg/kg of atropine sulfate i.m. 20 min prior to the administration of 1 mg/kg xykazine and 0,2 mg/kg midazolam (group m/m - n = 1 O) i.m .. The combination of alfa2 agonists and midazolam induced a rapid CNS depression. The onset of sedation was earlier with m/m than x/m. The maximal sedative effect occurred at 20 to 30 min with the two combinations and recovery was uneventful.