Avaliação cardiorrespiratória e de sedação da associação de dexmedetomidina-butorfanol-midazolam ou detomidina-butorfanol-midazolam em catetos (Pecari tajacu) / Cardiorespiratory and sedation evaluation of the combination of dexmedetomidine-butorphanol-midazolam or detomidine butorphanol-midazolam in collared peccaries (Pecari tajacu)

A presente pesquisa comparou os efeitos cardiorrespiratórios, hemogasométricos e sedativos da associação midazolam (0,41mg/kg) e butorfanol (0,31mg/kg) acrescida de detomidina (157µg/kg) (DTMB) ou dexmedetomidina (36µg/kg) (DXMB) em catetos. Catetos adultos (n=20) foram distribuídos em dois grupos, DTMB ou DXMB. As variáveis (FC, f, PAM, SpO2, EtCO2 e TR) foram avaliadas após aplicação dos fármacos. A sedação foi avaliada por meio de escala analógica visual, relaxamento muscular, postura e resposta auditiva. Foi realizada ANOVA, seguida de teste t pareado (paramétricos) e teste de Mann-Whitney rank-sum test (não paramétricos), com P<0,05. Não foi observada diferença estatística entre os grupos para o período de latência. Observou-se diferença significativa entre grupos para as variáveis f, PAM e SpO2, com maiores valores para DTMB, e EtCO2, com maiores valores para DXMB. Os dois grupos apresentaram redução da FC e da concentração de lactato, bem como aumento da concentração de bicarbonato. A SpO2 permaneceu abaixo de 90%, durante todo o período experimental, nos dois grupos estudados. Os animais dos dois grupos apresentaram sedação profunda e relaxamento muscular máximo. Conclui-se que os dois protocolos testados proporcionaram adequada sedação, podendo ser indicados para contenção química de catetos adultos.(AU)

The study compared the cardiorespiratory, hemogasometric and sedative effects of the combination of midazolam (0.41mg/kg) and butorphanol (0.31mg/kg) plus detomidine (157µg/kg) (DTMB) or dexmedetomidine (36µg/kg) (DXMB) in collared peccaries. Collared peccaries (n= 20) were divided into two groups, either DTMB or DXMB. The variables (FC, f, PAM, SpO2, EtCO2 and TR) were evaluated after application of the drugs. Sedation was assessed by visual analogue scale, muscle relaxation, posture and auditory response. ANOVA followed by paired t-test (parametric) and Mann Whitney Rank Sum Test (non-parametric) with P< 0.05 were performed. No statistical difference was observed for the latency period. A significant increase was observed between groups for the variables f, PAM and SpO2 with higher values for DTMB and EtCO2 with higher values for DXMB. The two groups presented a reduction in HR and lactate concentration, and an increase in bicarbonate concentration. SpO2 remained below 90% throughout the experiment in both groups. The animals of the two groups presented deep sedation and maximum muscle relaxation. It is concluded that the two protocols tested provided adequate sedation and could be indicated for chemical containment of collared peccaries.(AU)

Mapeamento comparativo de nervos periféricos em caninos e bovinos / Comparative mapping of peripheral nerves in dogs and cattle

O estudo dos dados anatômicos é fundamental para possibilitar ao médico veterinário o reconhecimento de pequenas estruturas, como os nervos nos animais, oferecendo subsídio para construção do conhecimento do profissional principalmente em técnicas anestésicas e cirúrgicas. Para investigar e mapear os nervos do plexo braquial (nervo radial, nervo musculocutâneo, nervo ulnar, nervo mediano), nervo isquiático, nervo tibial, nervo femoral e os nervos para bloqueio paravertebral, foram utilizados um cadáver canino adulto, de peso aproximado de 8kg, e um cadáver de bezerro Holandês, de peso aproximado de 40kg. O mapeamento dos nervos é de grande importância, já que conhecer bem essas estruturas permite ao veterinário um bom desenvolvimento de suas atividades profissionais a fim de exercer funções mais complexas durante a anestesia e cirurgia veterinária, uma vez que, identificados os pontos de referência anatômicos, é possível trabalhar com mais clareza nas técnicas de bloqueios dos nervos periféricos.(AU)

Knowledge of animal anatomy is essential for the veterinarian to identify small structures such as nerves, thus providing a solid background for the professional especially for surgical and anesthetic techniques. To investigate and map the nerves of the brachial plexus (radial, musculocutaneous, ulnar, median), sciatic, tibial, femoral and the nerves for paravertebral blocking in bovine, embalmed specimens were used. One adult male dog weighing approximately 8kg and one 40kg male calf were used. Nerve mapping is fundamental due to its interdisciplinary nature, thus providing the veterinarian with a major improvement in his/her professional activities which permits allows one to perform complex tasks in anesthesia and veterinary surgery. Knowledge ofanatomical reference points increases clarity and precision in techniques involving peripheral nerve blocks.(AU)

Efeitos de dois protocolos de sedação sobre as variáveis bioquímicas em gatos / Effects of two sedation protocols in biochemistry variables in cats

A utilização de protocolos de sedação como auxílio na contenção de felinos para realização de coletas de sangue é de grande importância, porém a utilização de alguns fármacos pode alterar resultados e a interpretação deles. Por outro lado, a contenção física pode gerar intenso estresse, especialmente em felinos, o que também pode interferir nos resultados. Este estudo teve como objetivo avaliar exames de bioquímica clínica sob o uso de contenção física e química em gatos submetidos a dois protocolos de sedação. Foram utilizados 50 gatos, 26 fêmeas e 24 machos, sem raça definida, submetidos a contenção física e, imediatamente após, a dois protocolos de sedação, DB (dexmedetomidina 5µg/kg e butorfanol 0,3mg/kg) e DBC (dexmedetomidina 5µg/kg, butorfanol 0,3mg/kg e cetamina 3mg/kg), aplicados por via intramuscular. Amostras de sangue foram coletadas após a contenção física e, em seguida, após o uso de um dos protocolos de sedação. Foram avaliados: ureia, creatinina, alaninoaminotransferase (ALT), fosfatase alcalina, proteína sérica total (PST), albumina, globulinas, colesterol, triglicérides, cálcio, magnésio e cloretos de amostras de soro, lactato e glicose de amostras de plasma fluoretado. Foi encontrada diferença estatística entre grupos para albumina, triglicérides, PST e colesterol, com maiores valores sendo encontrados no grupo DBC. Entre momentos, houve diferença para colesterol e fosfatase alcalina, com maiores valores no momento contenção física somente no grupo DBC. Já a glicose teve maiores valores após a sedação em ambos os grupos. O estudo revelou que o uso destes protocolos implica restrições para alguns parâmetros bioquímicos aqui estudados e que suas interpretações devem ser avaliadas cuidadosamente.(AU)

The use of sedation protocols to assist in the restraint of cats to perform blood collections is of great importance, but the use of some drugs can alter the results and interpretation. Moreover, the physical restraint may generate intense stress, especially in animals of the feline species, which may also interfere with the results. This study aimed to evaluate examinations of clinical biochemistry in the use of physical restraint and chemistry in cats subjected to two sedation protocols. We used 50 cats, 26 females and 24 males, of mixed-breed, who underwent physical restraint and immediately after underwent two sedation protocols, DB (dexmedetomidine 5µg / kg and 0.3mg butorphanol / kg) and DBC (dexmedetomidine 5µg / kg butorphanol 0.3mg / kg ketamine and 3mg / kg), applied intramuscularly. Blood samples were taken after physical restraint and then after the use of one of the sedation protocols. The following parameters were evaluated: urea, creatinine, alanine aminotransferase (ALT), alkaline phosphatase (ALP), total serum protein (TP), albumin, globulin, cholesterol, triglycerides, calcium, magnesium and chloride in serum samples, and lactate and glucose in fluoride plasma samples. Statistical difference was found between groups for albumin, triglycerides, TP and cholesterol with higher values being found in the DBC group. A statistical difference between moments was found for cholesterol, and ALP with higher values in physical restraint only in the DBC group. Glucose had greater values after sedation for both groups. The study revealed that the use of these protocols implies restrictions on some biochemical parameters studied here, and that their interpretations should be evaluated carefully.(AU)

Avaliação hemogasométrica em cadelas com piometra / Hemogasometric evaluation in bitches with pyometra

A piometra é uma afecção comum em cadelas com uma etiologia hormonal associada à infecção bacteriana, levando ao acúmulo de exsudato uterino. Desequilíbrios ácido-base e hidroeletrolíticos são complicações que contribuem para a progressão da doença, o que piora o estado geral da paciente e pode levá-la ao óbito. O objetivo do presente trabalho foi caracterizar os distúrbios ácido-base e eletrolíticos em cadelas com piometra, além de avaliar se a terapia hídrica pré-cirúrgica (Ringer lactato) é efetiva na correção desses desequilíbrios. Vinte cadelas com piometra foram submetidas à hemogasometria em oito tempos preestabelecidos. Concluiu-se que o distúrbio ácido-base mais frequente foi a alcalose respiratória e que a terapia hídrica no pré-cirúrgico com solução Ringer lactato foi efetiva na correção da acidose metabólica e proporcionou melhora na alcalose respiratória, embora não tenha corrigido quadros de alcalose metabólica.

Pyometra is a common disease in dogs with a hormonal etiology associated with a bacterial infection and leading to accumulation of uterine exudates. Acid-base and electrolyte disturbances are complications that contribute to disease progression, worsening the condition of the patient, possibly leading death. The aim of this study was to characterize the acid-base and electrolyte disturbances in dogs with pyometra, and to evaluate whether preoperative fluid therapy (Ringer's lactate) is effective in correcting these imbalances. Twenty bitches with pyometra were subjected to blood gas analysis in eight pre-set times. It was concluded that the acid-base disorder was the most frequent respiratory alkalosis and fluid therapy in the preoperative Ringer 's lactate solution was effective in the correction of metabolic acidosis, although this has not corrected metabolic alkalosis frames and has provided improved alkalosis breathing .

Avaliação da analgesia pós-operatória da metadona, da cetamina ou da sua associação em gatas submetidas a ovariossalpingo-histerectomia / Evaluation of postoperative analgesia of methadone, ketamine or their associations in cats undergoing ovariohysterectomy

A prevenção e o controle da dor são componentes básicos para um procedimento anestésico adequado. Objetivou-se com este estudo avaliar a analgesia pós-operatória da cetamina, em dose subanestésica, da metadona e da associação de ambas pela via intramuscular em felinos. Foram utilizadas 24 gatas, hígidas, submetidas à ovariossalpingo-histerectomia eletiva. No dia anterior ao início do estudo, os animais foram anestesiados para colocação de cateter na veia jugular, para posterior coleta de sangue para mensuração da concentração sérica do cortisol. No dia do experimento, os animais foram alocados aleatoriamente em três grupos (n=oito), os quais receberam cetamina (GC), na dose de 0,5mg/kg; ou metadona (GM), na dose de 0,3mg/kg; ou cetamina e metadona (GCM), nas doses de 0,5mg/kg e 0,3mg/kg, respectivamente, todos pela via intramuscular. Todos os grupos receberam os fármacos 20 minutos antes da indução anestésica, a qual foi realizada com propofol, e a manutenção com isoflurano. Os parâmetros avaliados foram a mensuração do cortisol nos momentos M0 (basal - antes da cirurgia), M1(transoperatório), M2, M3, M4, M8, M12 e M24 (duas, três, quatro, oito, 12 e 24 horas após o término da cirurgia),e a do escore de dor por meio da escala multidimensional de dor aguda em felinos nos momentos M0, M2, M3, M4, M8, M12 e M24. Os valores de cortisol foram maiores no GC em comparação ao GM e ao GCM em M2 e M3. Os escores de dor foram maiores no GC nos momentos M2 e M3 em comparação ao GM e ao GCM, respectivamente. No somatório de pontos, no M2, o GC apresentou valores maiores que o GM e o GCM, e, no M4, o GC obteve valores maiores que o GCM. Em relação ao número de resgates no pós-operatório no GC, 8/8 dos animais necessitaram de resgate, no GM 5/8 e no GCM 3/8. Conclui-se que a associação de metadona e cetamina em gatas submetidas à OSH eletiva promove analgesia pós-operatória adequada e, assim, reduz o requerimento de analgésicos no período pós-operatório.(AU)

The prevention and control of pain are basic components to have an adequate anesthesia. The aim of this study was to investigate the postoperative analgesia of ketamine in subanestesica dose, of methadone and the association of both intramuscularly in cats. A total of 24 cats proven healthy were referred for elective ovariossalpingohisterectomia. The day before the beginning of the experiment animals were anesthetized for placing a catheter in the jugular vein for subsequent blood sampling for measurement of serum concentration of cortisol. The next day, animals were randomly allocated to three groups (n = 8), which received ketamine (GC) at a dose of 0.5mg/kg; methadone (GM) at a dose of 0.3mg/kg; methadone and ketamine (GCM) at doses of 0.5mg/kg and 0.3mg/kg, respectively, all in the intramuscular route. All groups received the drug 20 minutes before induction of anesthesia, which was performed with propofol and maintained with isoflurane. The parameters evaluated were the measurement of cortisol in moments M0 (baseline-before surgery), M1(intraoperative), M2, M3, M4, M8, M12 and M24 (2,3,4,8,12 and 24 hours after the end of surgery) and evaluation of pain score by multidimensional scale of acute pain in cats in the moments M0, M2, M3, M4, M8, M12 and M24. The cortisol levels were higher in GC compared to GM and GCM in M2 and M3. Pain scores were higher in GC in moments M2 and M3 compared to GM and GCM, respectively. In summation of points in M2, GC showed higher values than GM and GCM, and M4, GC obtained values greater than GCM. Comparing the number of rescues postoperatively in GC 8/8 of animals required rescue, in GM /8 and in GCM 3/8. It was concluded that the combination of methadone and ketamine in cats undergoing elective OSH provides adequate postoperative analgesia, reducing the requirement for analgesics in the postoperative period.(AU)

Confiabilidade e pontuação mínima relacionada à intervenção analgésica de uma escala multidimensional para avaliação de dor pós-operatória em gatos / Reliability and cut-off point related to the analgesic intervention of a multidimensional composite scale to assess postoperative pain in cats

Avaliou-se a confiabilidade e determinou-se a pontuação mínima relacionada à necessidade de intervenção analgésica de uma escala multidimensional para avaliação de dor pós-operatória em gatas submetidas à ovário-histerectomia. Trinta gatas foram filmadas em quatro momentos predeterminados: pré-operatório, pós-operatório antes e depois da analgesia de resgate e às 24 horas após a cirurgia. Quatro observadores, não cientes dos momentos de avaliação, e um observador, considerado padrão-ouro - pesquisador que desenvolveu a escala - , avaliaram os vídeos em ordem aleatória, a partir da aplicação da escala, e determinaram a suficiência ou não de analgesia, baseando-se na experiência clínica. Os vídeos foram reavaliados dois meses após a primeira análise. O grau de concordância entre as avaliações dos diferentes observadores e das avaliações feitas pelo mesmo observador em diferentes ocasiões foi verificado pelo coeficiente de correlação intraclasse, que variou entre bom e muito bom para todos os itens da escala, exceto atividade, atitude e miscelânea de comportamentos que apresentaram confiabilidade moderada. O ponto de corte ótimo (> 7) foi selecionado pela análise descritiva e da curva Receiver Operating Characteristic. Os resultados suportam a confiabilidade em termos de reprodutibilidade e estabilidade e indicam que a terapia analgésica deve ser considerada em pontuações >8.

The aim with this study was to evaluate the reliability, and to establish the minimum score relating to the analgesic intervention of a multidimensional scale for use in assessing postoperative pain in cats undergoing ovariohysterectomy. Thirty cats were video recorded at 4 predetermined moments: prior to surgery, before and after rescue analgesia postoperatively, and 24 hours after surgery. Four observers blind to the times of assessment, and a gold standard observer (researcher who developed the scale) evaluated the video segments in random order using the scale, and determined the adequacy or not of analgesia based on clinical experience. The videos were reassessed two months after the first analysis. The agreement between the assessment of different observers, and the assessment made by the same observer on different occasions has been verified by the intra-class correlation coefficient that ranged from good to very good for all scale items, except activity, attitude and miscellaneous behaviors, which showed moderate reliability. The optimal cutoff point (> 7) was selected based on descriptive analysis and Receiver Operating Characteristic curve. The findings support the reliability in terms of reproducibility and stability, and indicate that analgesic therapy should be considered in scores >8.

Evaluation of von Willebrand factor during pregnancy, lactation and oestrous cycle in bitches affected and unaffected by von Willebrand disease.

Plasmatic concentrations of von Willebrand Factor (vWF) increase during pregnancy in humans and dogs; however the mechanism of such increase is still not well defined. The aims of this study were: (i) to evaluate changes in vWF concentration during pregnancy and during the subsequent oestrous cycle in bitches affected and unaffected by von Willebrand Disease (vWD); (ii) to correlate the vWF levels and cortisol levels in both groups. Seven vWD affected (GI) and nine unaffected (GII) bitches were used. The animals were assessed during pregnancy, parturition, lactation and non-gestational oestrous cycle in 11 moments (Pregnancy 1, Pregnancy 2, Parturition, Lactation 1, Lactation 2, Lactation 3, Anestrus, Proestrus, Oestrus, Diestrus 1, and Diestrus 2). The following tests were performed; measurement of von Willebrand factor antigen (vWF:Ag), albumin and cortisol. In both groups, vWF concentration remained stable during the non-gestational oestrous cycle, but increased during pregnancy, with the highest value observed at parturition. Increases of 70% and 124% in vWF were seen in GI and GII, respectively, compared to anestrus. No correlation was found between vWF and cortisol. Values of vWF:Ag changed during pregnancy, with a peak at parturition, both in vWD affected and unaffected animals. Values of vWF were not altered in the different phases of the oestrous cycle following pregnancy in both groups. Evaluation of vWF during pregnancy can cause false negative results for vWD, but assessment can be performed at any point in the oestrous cycle of non-pregnant bitches.

Validade e responsividade de uma escala multidimensional para avaliação de dor pós-operatória em gatos / Validity and responsiveness of a multidimensional composite scale to assess postoperative pain in cats

O manejo adequado da dor depende de métodos de avaliação acurados. O objetivo deste estudo foi avaliar a validade e a responsividade de uma escala multidimensional para avaliação de dor pós-operatória em gatas submetidas à ovário-histerectomia. Trinta gatas foram filmadas no período perioperatório em quatro momentos predeterminados: pré-operatório, pós-operatório antes e depois da analgesia de resgate e às 24 horas após o término da cirurgia. Cinco observadores não cientes dos momentos de avaliação e um observador considerado padrão-ouro (pesquisador que desenvolveu a escala) avaliaram os vídeos em ordem aleatória e determinaram os escores de dor dos animais, utilizando a escala a ser validada. A responsividade e a validade de conteúdo e constructo foram estabelecidas pelo aumento e pela redução significativa nos escores de dor, em resposta ao procedimento cirúrgico e à administração de analgesia de resgate, respectivamente, avaliados pelo teste de Wilcoxon (P<0,001). A validade de critério foi atestada pela concordância alta entre as avaliações do padrão-ouro com os demais observadores, analisada pela porcentagem de absoluta concordância e coeficiente Kappa ponderado. Os resultados suportam a validade e a responsividade de uma escala multidimensional para avaliação de dor aguda pós-operatória em gatas submetidas à ovário-histerectomia, quando utilizada por veterinários formados e com experiência clínica.

Adequate pain management depends on accurate assessment methods. The aim of this study was to evaluate the validity and responsiveness of a multidimensional composite scale for use in assessing postoperative pain in cats undergoing ovariohysterectomy. Thirty cats were video recorded in four predetermined moments during the perioperative period: prior to surgery, before and after rescue analgesia postoperatively, and 24 hours after the end of surgery. Five observers blind to the times of assessment, and a gold standard observer (researcher who developed the scale) viewed the video segments in a random order, and the cat's pain scores were registered using the scale to be validated. The content and construct validity, and the responsiveness were established based on significant increase and reduction in the pain scores, in response to surgery and analgesics administration, respectively (Wilcoxon signed rank test, P<0.001). Criterion validity was determined by high agreement between the evaluations of the gold standard with the other observers, assessed by the percentage of absolute agreement and weighted Kappa coefficient. The findings support the validity and the responsiveness of a multidimensional composite scale to assess postoperative acute pain in cats undergoing ovariohysterectomy, when used by veterinarians with clinical experience.

Effects of feeding a multivalent polyclonal antibody preparation on feedlot performance, carcass characteristics, rumenitis, and blood gas profile in Bos indicus biotype yearling bulls.

The objective of this study was to evaluate effects of feeding monensin (MON) or a multivalent polyclonal antibody preparation (PAP) against several rumen microorganisms on feedlot performance, carcass characteristics, blood gas profile, and rumenitis of Bos indicus biotype (BT) yearling bulls. The study was designed as a completely randomized design with a 3 × 2 factorial arrangement, replicated 4 times, in which 32 yearling bulls of each of 3 BT evaluated (3-way-cross, TC; Canchim, CC; and Nellore, NE) were fed diets containing either MON at 300 mg·d(-1) or PAP at 10 mL·d(-1) across 3 different periods. No significant (P > 0.10) feed additive (FA) main effects were observed for any of the feedlot performance variables and carcass characteristics with the exception of dressing percentage. Yearling bulls receiving PAP had a decreased (P = 0.047) dressing percentage when compared with yearling bulls receiving MON. Significant (P < 0.05) BT main effects were observed for all feedlot performance variables and carcass characteristics with the exception of kidney-pelvic fat expressed in kilograms (P = 0.49) and LM lipids content (P = 0.45). Crossbred yearling bulls (TC and CC) had greater (P < 0.001) ADG, DMI in kilograms, DMI as % of BW, and improved (P = 0.001) G:F when compared with NE yearling bulls. A tendency (P = 0.072) for a FA main effect was observed for rumenitis scores, in which yearling bulls receiving PAP had lesser rumenitis scores than those receiving MON. When the data were disposed as frequency percentage, 55.6% and 45.7% of the rumens from yearling bulls fed PAP and MON were scored between 0 and 1, respectively (0 = no lesions, 10 = severe lesions). Likewise, a significant BT main effect was observed (P = 0.008), where NE yearling bulls had greater rumenitis scores than those of crossbred yearling bulls (TC and CC). No significant FA main effects were observed (P > 0.10) for any of the fatty acids measured in the subcutaneous adipose tissue, with the exception that yearling bulls receiving MON had greater (P < 0.05) concentrations of palmitic acid (16:0), margaric acid (17:0), docosapentaenoic acid (22:5), and docosahexaenoic acid (22:6) than those yearling bulls receiving PAP. Feeding PAP tended to decrease incidence of rumen lesions and led to similar feedlot performance compared with feeding MON. Thus, PAP is a new technology that presents a possible alternative for ionophores.

Comparação entre a lidocaína e a acupuntura no tratamento da taquicardia ventricular induzida com dopamina em equinos anestesiados com halotano / Comparative study between lidocaine and acupunture in the treatment of ventricular tachycardia induced by dopamine in horses anesthetized with halothane

Os efeitos da lidocaina e da acupuntura nos pontos bilaterais associados ao pericárdio 6 (Pc6-Neiguan) e ao coração 7 (C7-Shenmen), no tratamento da taquicardia ventricular (TV) induzida por dopamina em equinos anestesiados com halotano, foram avaliados e comparados. Seis equinos, distribuídos em três grupos: grupo-controle (GC), grupo tratado com acupuntura (GA) e grupo tratado com lidocaína (GL), foram anestesiados três vezes cada, com intervalo de uma semana entre cada anestesia. Avaliaram-se os parâmetros cardiovasculares (frequência cardíaca, pressão arterial e eletrocardiografia), os respiratórios (frequência respiratória, capnografía, saturação de hemoglobina e hemogasometria) e o escore de recuperação. A dose arritmogênica da dopamina (DAD) foi determinada a partir da infusão de 70µg/kg/min IV durante 10 minutos, sem interrupção, preenchendo o critério arritmogênico: quatro ou mais complexos ventriculares prematuros seguidos, com duração de pelo menos 15 segundos ou TV sustentada. O tempo médio de aparecimento da DAD ou da TV foi de 6,05±0,45 minutos nos animais não tratados, e a TV se reverteu espontaneamente aos 2,7±0,2 minutos. O grupo tratado com acupuntura reverteu a TV no tempo médio de 1,8±0,2 (P<0,05) em relação ao grupo tratado com lidocaina 1,3±0,2 (P<0,01). Os tratamentos mostraram-se eficientes na reversão TV.

The effects of lidocaine and acupuncture in the associated bilateral points, i.e. pericardium 6 (Pc 6- Neiguan) and heart 7 (H7 - Shenmen), on the ventricular tachycardia (VT) induced by dopamine were evaluated in horses anesthetized with halothane. Six horses were distributed in three groups: control group (CG), acupuncture treated group (AG), and lidocaine treated group (LG). They were anesthetized three times each one using halothane with one week interval between each anesthesic procedure. Cardiovascular (heart rate, arterial pressure, and ECG) and respiratory (respiratory rate, capnometry, hemoglobin saturation, and blood gas analysis) parameters and recovery score were evaluated. The arrhythmogenic dose of dopamine (ADD) was determined by the infusion of 70mg/kg/min during 10 minutes without interruption fulfilling the arrhythmogenic criterion by the presence of four or more ectopic ventricular contractions during at least 15 seconds or maintained VT. The mean time for the occurrence of ADD or VT was 6.05 ± 0.45 minutes in no treated animals and the VT reverted spontaneously in 2.7 ± 0.2 minutes. The group treated with acupuncture reverted the VT in a mean time of 1.8 ± 0.2 (P<0.05) compared to the group treated with lidocaine 1.3±0.2 (P<0.01), both of them were efficacious for the treatment of VT.

Comparison of the cardio-respiratory effects of methadone and morphine in conscious dogs.

The effects of methadone and morphine were compared in conscious dogs. Six animals received morphine sulfate (1 mg/kg) or methadone hydrochloride (0.5 mg/kg [MET0.5] or 1.0 mg/kg [MET1.0]) intravenously (i.v.) in a randomized complete block design. Cardiopulmonary variables were recorded before (baseline), and for 120 min after drug administration. One outlier was not included in the statistical analysis for hemodynamic data. Morphine decreased heart rate (HR) compared to baseline from 30 to 120 min (-15% to -26%), while cardiac index (CI) was reduced only at 120 min (-19%). Greater and more prolonged reductions in HR (-32% to -46%) and in CI (-24% to -52%) were observed after MET1.0, while intermediate reductions were recorded after MET0.5 (-19 to -28% for HR and -17% to -27% for CI). The systemic vascular resistance index (SVRI) was increased after methadone; MET1.0 produced higher SVRI values than MET0.5 (maximum increases: 57% and 165% for MET0.5 and MET1.0, respectively). Compared to morphine, oxygen partial pressure (PaO(2)) was lower (-12% to -13%) at 5 min of methadone (0.5 and 1.0 mg/kg), while carbon dioxide partial pressure (PaCO(2)) did not change significantly. It was concluded that methadone induces cardiovascular changes that are dose-related and is a more potent cardiovascular depressant agent than morphine in conscious dogs.