In vivo evaluation of a polyester and fiberglass composite intramedullary nail for femoral osteosynthesis in calves.

The objective of this study was to test a composite of polyester resin and fiberglass in the form of an intramedullary nail for osteosynthesis of femoral fractures in calves. The methodology was established based on a previous study that used a bovine femur finite element model to simulate fractures, which were then stabilized by the same nails as proposed in this study. General anesthesia was induced in six calves followed by fracture creation via an oblique incision in the middle third of the femoral diaphysis, and osteosynthesis was immediately performed by retrograde insertion of the composite nail. Locking was achieved by drilling the bone and nail without using a jig and introducing two stainless steel screws proximal and two distal to the fracture line. Five of the six calves achieved complete fracture healing after 60 days. No signs of incompatibility or toxicity of the composite were observed. However, limitations were observed during the surgery, such as difficulty in drilling the nail and trimming the remainder portion of the nail that extended beyond the length of the bone. Small fragments produced by these maneuvers were considered irritating to soft tissues during the postoperative period. It was also found that small cracks in the nail tended to propagate in the form of longitudinal fractures. In conclusion, an intramedullary nail made of polyester resin and fiberglass (a low-cost and easy-to-acquire material) was considered biocompatible and capable of allowing bone healing of femoral fractures in young cattle. However, the development of solutions for the reported limitations is crucial prior to recommending the proposed composite for clinical use.

Administração seriada de salina hipertônica 7, 5% na terapia para sepse grave decorrente da síndrome da diarreia hemorrágica aguda em cães / Serial administration of 7. 5% hypertonic saline solution in the therapy of severe sepsis due to acute hemorrhagic diarrhea syndrome in dogs

Na clínica de animais de companhia é frequente cães com síndrome da diarreia hemorrágica aguda associada a quadros de sepse, o que acarreta alta mortalidade. Nesse contexto, objetivou-se, em um ensaio clínico controlado aleatorizado de centro único, estudar os efeitos tardios da solução salina hipertônica a 7,5% em aplicações seriadas, sobre variáveis hemodinâmicas, clínicas e laboratoriais em cães com quadro de sepse grave decorrente desta síndrome. Para tal, 12 cães foram aleatoriamente distribuídos em dois grupos de igual número, sendo um controle (CON) e o outro, solução salina hipertônica 7,5% (SSH). Variáveis clínicas e laboratoriais foram avaliadas imediatamente após a admissão do paciente (T0), 24 (T24), 48 (T48) e 72 (T72) horas após a admissão. O grupo SSH recebeu Ringer com lactato, antibioticoterapia, analgésico e SSH 7,5% em bolus (5mL kg-1 em 4 minutos) no T24 e no T48. O grupo CON recebeu a mesma terapia acima, porém ao invés da utilização de SSH a 7,5%, administrou-se bolus de solução de Ringer lactato na mesma dose e tempos utilizado. As avaliações em cada tempo foram realizadas anteriormente à administração dos bolus, nos dois grupos. Avaliaram-se hemograma completo e as variáveis clínicas (escala AVDN, grau de desidratação, frequência respiratória e temperatura retal), frequência cardíaca (FC), pressão arterial sistólica (PAS). Os dados paramétricos foram avaliados pelos testes Student Newman Keuls e teste t de Student, e os não paramétricos pelo teste de Friedman e Mann Whitney, com nível de significância de P≥0,05. Nas variáveis clínicas estudadas não se observou diferença entre os grupos e entre os momentos avaliados. Observou-se diferença significativa no grupo SSH no T72, com elevação da PAS e redução da FC, fato não observado no grupo CON, onde esses parâmetros não se alteraram. O hematócrito e a concentração de hemoglobina diminuíram em ambos os grupos com o tempo. As contagens dos leucócitos totais e dos monócitos apresentaram uma elevação significativa no grupo SSH, estando os leucócitos dentro da faixa de normalidade no T72. Não houve diferenças significativas em relação aos neutrófilos segmentados, porém no grupo SSH verificou-se aumento de 9,5 vezes no T72 comparado com o T24 (P=0,09), enquanto que este aumento foi de apenas 2,5 vezes no grupo CON (P=0,30). Observou-se ainda redução nas contagens de plaquetas e na concentração de globulinas no grupo COM, enquanto essas variáveis se mantiveram estáveis no grupo SSH. Conclui-se que a administração seriada de SSH 7,5% se mostrou promissora no tratamento de cães com síndrome da diarreia hemorrágica aguda, pois auxilia na estabilização dos leucócitos, plaquetas e globulinas de cães com sepse grave decorrente da síndrome da diarreia hemorrágica aguda.(AU)

The association between acute hemorrhagic diarrhea syndrome and sepsis is frequent in dogs and causes high mortality. In this context we investigated in a randomized single-center controlled trial the late effects of 7.5% hypertonic saline solution in serial applications on hemodynamic, clinical and laboratory variables in dogs with severe sepsis due to the syndrome. Twelve dogs were randomly distributed into two groups of equal numbers, control (CON) and 7.5% hypertonic saline solution (SSH). Clinical and laboratory variables were evaluated immediately after admission of patients (T0), 24 (T24), 48 (T48) and 72 (T72) hours after the admission. The SSH group received Ringer with lactate, antibiotic therapy, analgesic and 5mL/kg-1 bolus of 7.5% SSH over 4 minutes on T24 and T48. The CON group received the same therapy, but instead of 7.5% SSH, Ringer with lactate bolus was given at the same dosis and times. All evaluations were performed prior to the administration of the bolus in both groups. Data collection included complete blood count and clinical variables (AVDN scale, degree of dehydration, respiratory rate and rectal temperature), heart rate (HR) and systolic blood pressure (SBP). Parametric data were evaluated by the Student Newman Keuls and Student t tests, and the nonparametric ones by the Friedman and Mann Whitney test, with a significance level of 0.05. There were no significant differences between the groups and moments in clinical variables. Nevertheless, the SSH group presented a significant elevation of SBP and HR reduction at T72. Hematocrit and hemoglobin concentration decreased in both groups over time. Total leukocyte and monocyte counts showed a significant elevation in the SSH group, however the leukocytes were within the normal range at T72. There were no significant differences in the segmental neutrophils, but a 9.5-fold increase in T72 compared to T24 (P=0.09) in the SSH group was observed, whereas this increase was only 2.5-fold in the CON group (P=0.30). A decrease in platelet counts and globulin concentration was observed in the CON group, while these variables remained stable in the SSH group. In conclusion, serial administration of 7.5% SSH is promising in the therapy of dogs with acute hemorrhagic diarrhea syndrome, since it assists in the stabilization of leukocytes, platelets and globulins in dogs with severe sepsis due to this syndrome.(AU)

Hematological and splenic Doppler ultrasonographic changes in dogs sedated with acepromazine or xylazine.

OBJECTIVE: To evaluate the onset and duration of hematological changes and the use of Doppler ultrasound (spleen) in dogs sedated with acepromazine or xylazine. STUDY DESIGN: Clinical study. ANIMALS: A total of 24 mixed breed dogs aged 1-4 years and weighing 15-25 kg. METHODS: Dogs were randomly distributed into two groups: acepromazine group (AG) which were administered acepromazine (0.05 mg kg-1) intramuscularly and xylazine group (XG) administered xylazine (0.5 mg kg-1) intramuscularly. Sonographic evaluations (morphologic and hemodynamic splenic vascularization) and hematologic tests were performed before drug administration (baseline) and 5, 15, 30, 60, 120, 240, 360, 480 and 720 minutes after drug administration. RESULTS: A significant reduction occurred in erythrogram variables in AG at 15-720 minutes corresponding with a significant enlargement of the spleen. In XG, a significant reduction was observed in the erythrogram variables at 30-60 minutes without a significant enlargement of the spleen. Hilar diameter did not change over time in either group. Flow alterations were found only in the splenic artery in AG, with a decreased final diastolic velocity observed at 60-120 minutes. CONCLUSIONS: Administration of acepromazine resulted in decreased red blood cell count, hemoglobin, packed cell volume and an increased diameter of the spleen. Xylazine administration resulted in similar hematologic changes but of smaller magnitude and duration and without splenic changes. The absence of significant changes in the Doppler flow parameters of the splenic artery and vein and the hilar diameter suggests that the splenomegaly that was observed in AG was not due to splenic vasodilation. No splenic sequestration occurred after xylazine administration. CLINICAL RELEVANCE: The results indicate that acepromazine decreases the erythrocyte concentrations by splenic erythrocyte sequestration and concomitant splenomegaly. Xylazine can cause slight hematologic changes, but without splenic changes.

Hemodynamic effects of target-controlled infusion of propofol alone or in combination with a constant-rate infusion of remifentanil in dogs.

The objective of this study was to evaluate the hemodynamic effects of target-controlled infusion (TCI) of propofol alone or in combination with a constant-rate infusion (CRI) of remifentanil. Six adult dogs were given 2 treatments in a randomized crossover study with a 7-day interval between treatments. Treatment 1 was propofol (P) and treatment 2 was propofol and remifentanil (P-Rem), without any premedication. Propofol was induced using a TCI system with a predicted plasma concentration (Cp) of 6.0 µg/mL. Anesthesia was maintained within the Cp range (0.65 to 3.0 µg/mL) for 120 min and remifentanil was administered at a rate of 0.3 µg/kg body weight (BW) per minute, CRI. Cardiopulmonary variables were recorded before (baseline), during, and 120 min after drug administration. Heart rate (HR) decreased significantly in the P-Rem group (46%) compared with baseline values. In the P-Rem group, the cardiac index (CI) decreased significantly (49% to 58%) and the stroke volume (SV) decreased compared with baseline values. The systemic vascular resistance index (SVRI) increased significantly in the P-Rem group compared with baseline values. There was no difference in mean arterial pressure (MAP) between the groups. Central venous pressure (CVP) and pulmonary artery occlusion pressure (PAOP) significantly increased in the P-Rem group compared with baseline values. In conclusion, the hemodynamic changes observed in this study indicate a compromise of the cardiovascular system, although the dogs in this study were healthy/euvolemic and there was no change in preload. More studies are required in order to evaluate the actual safety of the combination of propofol and remifentanil in patients with reduced cardiac reserve.

L'objectif de la présente étude était d'évaluer les effets hémodynamiques d'une infusion à objectif de concentration (IOC) de propofol uniquement ou en combinaison avec une infusion à débit constant (IDC) de remifentanyl. Six chiens adultes reçurent deux traitements dans un essai aléatoire croisé avec un intervalle de sept jours entre les traitements. Le traitement 1 consistait en du propofol (P) et le traitement 2 était du propofol et du remifentanyl (P-Rem), sans aucune prémédication. Le propofol fut induit à l'aide d'un système d'IOC avec une concentration plasmatique prédéterminée (Cp) de 6,0 mg/mL. L'anesthésie fut maintenue à l'intérieur de l'écart de Cp (0,65 à 3,0 µg/mL) pendant 120 min et du remifentanyl administré à un taux de 0,3 µg/kg de poids corporel (PC) par minute, IDC. Les variables cardiopulmonaires furent enregistrées avant (valeurs de base), pendant, et 120 min après l'administration des médicaments. Le rythme cardiaque (RC) a diminué significativement dans le groupe P-Rem (46 %) comparativement aux valeurs de base. Dans le groupe P-Rem, l'index cardiaque (IC) a diminué significativement (49 % à 58 %) et le volume du débit systolique (VDS) a diminué comparativement aux valeurs de base. L'index de résistance vasculaire systémique (IRVS) a augmenté de manière significative dans le groupe P-Rem comparativement aux valeurs de base. Il n'y avait aucune différence entre les groupes pour la pression artérielle moyenne (PAM). La pression veineuse centrale (PVC) et la pression d'occlusion de l'artère pulmonaire (POAP) ont augmenté significativement dans le groupe P-Rem comparativement aux valeurs de base. En conclusion, les changements hémodynamiques observés dans cette étude indiquent un compromis du système cardio-vasculaire, bien que les chiens utilisés étaient en santé/euvolémiques et qu'il n'y avait pas de changement dans la précharge. Des études supplémentaires sont requises afin d'évaluer la sécurité de la combinaison de propofol et de remifentanyl chez des patients avec une réserve cardiaque diminuée.(Traduit par Docteur Serge Messier).

Efeitos sedativos da associação de Cetamina e Midazolam administrados pela via intranasal ou intramuscular em papagaio (Amazona aestiva e Amazona vinacea) / Sedative effects of the association Ketamine and Midazolam administered intranasally or intramuscular in parrots (Amazona aestiva and Amazona vinacea)

A falta de protocolos de sedação seguros para uso em papagaios na literatura demonstra a necessidade de conhecer os anestésicos que são eficazes nestes animais. Devido a pouca massa muscular desta espécie, notou-se a necessidade de estudar outra via de administração, menos invasiva e dolorosa ao animal, como a via intranasal. O objetivo deste estudo foi avaliar os efeitos sedativos e a viabilidade da administração intranasal, em comparação à via intramuscular, de 15mg/kg de Cetamina e 1mg/kg de Midazolam. Foram utilizados 14 papagaios das espécies Amazona aestiva e Amazona vinacea, de ambos os sexos, adultos, peso médio de 388,5±29,1g. Os animais foram distribuídos aleatoriamente em dois grupos: intramuscular (IM, n=7) e intranasal (IN, n=7). No grupo intramuscular, a administração dos anestésicos foi realizada nos músculos peitorais, utilizando seringas de insulina e no grupo intranasal, com auxílio de uma micropipeta. Avaliou-se o período de latência, tempo de duração, qualidade de sedação, e o tempo de recuperação total. A média para o período de latência no grupo IM foi de 6,13±2,02 minutos e no grupo IN de 4,84±2,37 minutos. Já para o tempo de duração da sedação no grupo IM a média foi de 35,81±29,56 e no grupo IN de 24,52±14,83 minutos. Ambas as vias promoveram sedação adequada, pois a média do escore da qualidade de sedação obtida pelo grupo IM foi 2±1,5 e pelo grupo IN 1,28±1,1. O tempo de recuperação total no grupo IM foi de 27,04±11,69 e no grupo IN de 17,67±11,64 minutos. Apesar do grupo IN ter apresentado os menores tempos de período de latência, duração e de recuperação total e ter obtido melhor escore na qualidade de sedação, não houve diferença estatística significativa entre os grupos. Os resultados obtidos neste estudo indicam que a administração de 15 mg/kg de cetamina e 1mg/kg de midazolam pela via intranasal ou intramuscular em papagaios (Amazona aestiva e Amazona vinacea) produzem sedação adequada para pequenos procedimentos como colocação de anilha, coleta de sangue e radiografias; porém a via intranasal mostrou ser uma alternativa menos invasiva quando comparado à via intramuscular.

The lack of safe sedation protocols for use in parrots in the literature, demonstrate the need to know that the anesthetics are effective in these animals. Due to low muscle mass this bird, it was noted the need to consider other routes of administration, less invasive and painful to the animal, such as intranasal. The aim of this study was to evaluate sedative effects of intranasal administration compared to intramuscular 15mg.kg-1 of Ketamine and Midazolam 1mg.kg-1. We used 14 parrots (Amazona aestiva and Amazona vinacea), adults, and mean weight of 388.5±29.1g. The animals were randomly into two groups: intramuscular (IM, n=7) and intranasal (IN, n=7). In group intramuscular, administration of anesthetics was performed in the pectoral muscles, using insulin syringes and intranasal group with a micropipette. We evaluated the latency period, duration, quality of sedation, and the total recovery time. The average for the period of latency in the IM group was 6.13±2.02 and IN group 4.84±2.37 minutes. As for the duration of sedation in the IM group was 35.81±29.56 and in IN group 24.52±14.83 minutes. Both pathways promoted adequate sedation, the mean score for the quality of sedation obtained by the IM group was 2±1.5 and 1.28±1.1 in the IN group. The total recovery time in the IM group was 27.04±11.69 and 17.67±11.64 minutes in the IN group. Although the IN group the lowest times of onset, duration and full recovery and have better scores on quality of sedation, there was no statistically significant difference between groups. The results of this study indicate that administration of ketamine (15mg.kg-1) and midazolam (1mg.kg-1) intranasal or intramuscular in parrots (Amazona aestiva/Amazona vinacea) produce adequate sedation for minor procedures, but the intranasal route could be an alternative less invasive when compared to intramuscular injection.

Efeitos anestésicos da administração intranasal ou intramuscular de cetamina S+ e midazolam em pomba-rola (Streptotelia sp) / Anesthetic effects of intranasal or intramuscular administration of S+ Ketamine and Midazolam in ring necked dove (Streptotelia sp)

A via intranasal é uma boa alternativa por ser indolor e de fácil aplicação em aves. O objetivo deste estudo foi avaliar os efeitos anestésicos da associação de cetamina S+ e midazolam pela via intranasal (IN) em comparação com a via intramuscular (IM) em pombos. Foram utilizados 12 pombos alocados em dois grupos com 15 dias de intervalo, os quais receberam: grupo IM: 20 mg/kg de cetamina S+ associada a 3,5 mg/kg de midazolam pela via intramuscular (musculatura do peito); e grupo IN, mesmo protocolo, porém, pela via intranasal. Os parâmetros avaliados foram: período de latência, tempo de duração em decúbito dorsal, tempo total de anestesia, tempo de recuperação e efeitos adversos. Para a análise estatística, empregou-se o teste de Wilcoxon, com as diferenças consideradas significativas quando P<0,05. O período de latência obtido foi de 30 [30-47,5] e 40 [30-50] segundos para IM e IN, respectivamente. O tempo de duração de decúbito dorsal foi de 59 [53,25-65] e 63 [37-71,25] minutos para IM e IN, respectivamente, sem diferenças significativas entre os grupos. Com relação à duração total de anestesia, foi observada diferença significativa, com 88 [86,25-94,5] e 68 [53,5-93] minutos para os grupos IM e IN, respectivamente. O tempo de recuperação foi mais curto no grupo IN (15 [4,25-19,5]) comparado ao IM (32 [28,25-38,25] minutos). Dois animais de cada grupo apresentaram regurgitação na fase de recuperação. Conclui-se que a administração de cetamina S+ e midazolam pela via intranasal é um método aceitável de administração de fármacos e produz anestesia rápida e eficaz em pombos.

The intranasal route is a good alternative because is painless and easy to perform in birds. The objective of this study was to evaluate the anesthetic effects of S+ ketamine and midazolam administered by intranasal or intramuscular route in pigeons. Twelve animals were used in a randomized and crossover design. Animals received two treatments with 2-weeks interval. IM group: animals received 20mg/kg of S+ ketamine and 3.5mg/kg of midazolam by intramuscular route (pectoral muscles); IN group: animals received the same protocol by intranasal route. Parameters evaluated were: onset of action, time of duration in dorsal recumbency; total time of anesthesia and side effects. Statistical analysis was performed using Wilcoxon test and the differences were considered significant when P<0.05. Onset of action was 30 [30-47.5] and 40 [30-50] seconds for IM and IN respectively. Time of duration in dorsal recumbency was 59 [53.25-65] and 63 [37-71.25] minutes for IM and IN respectively, without significant differences between treatments. Total time of anesthesia was 88 [86.25-94.5] and 68 [53.5-93] minutes for IM and IN, respectively, with significant difference between groups. The recovery time was lower for IN (15[4.25-19.5] minutes) compared with IM (32 [28.25-38.25] minutes). Two animals of each group presented regurgitation in the recovery period. It was concluded that S+ ketamine and midazolam administered intranasal is an acceptable method of drug delivery and can be used to promote anesthesia in pigeons.

Hematologic, serum biochemistry and urinary values for captive Crab-eating Fox (Cerdocyon thous) in São Paulo state, Brazil / Valores hematologicos, de bioquímica sérica e urinários para Cachorro-do-mato (Cerdocyon thous) de cativeiro no estado de São Paulo

The importance of studies with hematological, serum biochemistry and urinary values of Crab-eating Fox (Cerdocyon thous) is based on the need for health care and maintenance of those populations. This paper has the objective to investigate hematological, serum biochemistry and urinary physiological parameters of the Crab-eating fox, comparing gender and age differences. Blood samples were collected in 2003 from 52 animals of different Zoos in São Paulo state, Brazil; 7mL of blood was used to obtain a complete blood cell count (CBC) and the profile of the serum biochemistry. Moreover, 5mL of urine were collected for analysis. There was no difference in values for male and female animals, as for the CBC and serum biochemistry. Some hematological and serum biochemical parameters were influenced by age, showing significant differences. Urinalysis results were just demonstrated in a descriptive form. The studied values were, RBC 4.35±0.73 x 10(6) /µL, WBC 7.72±3.66 x 10³ /µL (predominance of segmented neutrophils), platelets 227.06±111.58 x 10³ /µL, urea 43.06±14.28mg/dL and creatinine 1.03±0.24mg/dL. Hematological, serum biochemistry and urinary values obtained in this study can be used as physiological values of the captive Crab-eating Fox. It is possible to conclude that wild species need their own reference values, differentiating animals in captivity from free-ranging animals.

A importância do estudo dos valores hematológicos, de bioquímica sérica e urinários de Cachorro-do-mato (Cerdocyon thous) baseia-se na necessidade de cuidados e manutenção da sanidade destas populações. Este estudo visou investigar os parâmetros fisiológicos hematológicos, de bioquímica sérica e urinários dos Cachorros-do-mato de cativeiro, comparando as possíveis diferenças sexuais e de faixa etária. Foram colhidas amostras de sangue de 52 animais, pertencentes a diversos Zoológicos do Estado de São Paulo, Brasil. Foram colhidos cerca de 7mL de sangue, que foram utilizados para se obter os valores hematológicos e o perfil de bioquímica sérica. Também foram colhidos 5mL de urina para realização da urinálise. Não se encontraram diferenças entre os valores obtidos para machos e fêmeas tanto na hematologia, quanto na bioquímica sérica. Alguns parâmetros hematológicos e de bioquímica sérica foram afetados pela idade, mostrando diferenças significativas. Os resultados da urinálise foram demonstrados apenas em forma descritiva. Os principais valores encontrados foram, hemácias 4,35+0,73 x 106 células /µL, leucócitos totais 7,72+3,66 x 103 células /µL (predomínio de neutrófilos segmentados), plaquetas 227,06+111,58 x 103 células /µL, ureia 43,06+14,28mg/dL e creatinina 1,03+0,24mg/dL. Os valores hematológicos, de bioquímica sérica e urinários obtidos neste estudo podem ser utilizados como valores fisiológicos de Cachorros-do-mato de cativeiro. Pode-se concluir que as espécies silvestres necessitam de seus próprios valores de referência com necessidade de se diferenciar animais em cativeiro de animais de vida livre.

Minimum infusion rate and hemodynamic effects of propofol, propofol-lidocaine and propofol-lidocaine-ketamine in dogs.

OBJECTIVE: To evaluate the effects of a constant rate infusion (CRI) of lidocaine alone or in combination with ketamine on the minimum infusion rate (MIR) of propofol in dogs and to compare the hemodynamic effects produced by propofol, propofol-lidocaine or propofol-lidocaine-ketamine anesthesia. STUDY DESIGN: Prospective, randomized cross-over experimental design. ANIMALS: Fourteen adult mixed-breed dogs weighing 15.8 ± 3.5 kg. METHODS: Eight dogs were anesthetized on different occasions to determine the MIR of propofol alone and propofol in combination with lidocaine (loading dose [LD] 1.5 mg kg(-1), CRI 0.25 mg kg(-1) minute(-1)) or lidocaine (LD 1.5 mg kg(-1), CRI 0.25 mg kg(-1) minute(-1)) and ketamine (LD 1 mg kg(-1), CRI 0.1 mg kg(-1) minute(-1)). In six other dogs, the hemodynamic effects and bispectral index (BIS) were investigated. Each animal received each treatment (propofol, propofol-lidocaine or propofol-lidocaine-ketamine) on the basis of the MIR of propofol determined in the first set of experiments. RESULTS: Mean ± SD MIR of propofol was 0.51 ± 0.08 mg kg(-1) minute(-1). Lidocaine-ketamine significantly decreased the MIR of propofol to 0.31 ± 0.07 mg kg(-1) minute(-1) (37 ± 18% reduction), although lidocaine alone did not (0.42 ± 0.08 mg kg(-1) minute(-1), 18 ± 7% reduction). Hemodynamic effects were similar in all treatments. Compared with the conscious state, in all treatments, heart rate, cardiac index, mean arterial blood pressure, stroke index and oxygen delivery index decreased significantly, whereas systemic vascular resistance index increased. Stroke index was lower in dogs treated with propofol-lidocaine-ketamine at 30 minutes compared with propofol alone. The BIS was lower during anesthesia with propofol-lidocaine-ketamine compared to propofol alone. CONCLUSIONS AND CLINICAL RELEVANCE: Lidocaine-ketamine, but not lidocaine alone, reduced the MIR of propofol in dogs. Neither lidocaine nor lidocaine in combination with ketamine attenuated cardiovascular depression produced by a continuous rate infusion of propofol.

Avaliação dos parâmetros cardiorrespiratórios, hemogasométricos e da concentração plasmática de cortisol em bovinos submetidos à imobilização eletromagnética / Evaluation of the cardiorrespiratory and hemogasometrics effects and cortisol plasmatic concentration in bovine submitted of electromagnetic immobilization

As formas de imobilização em bovinos mais utilizadas levam a uma manipulação excessiva e consequentemente estressante para o animal. A dor é uma experiência emocional de sensação desagradável que vem associada a um prejuízo tecidual. Surge no mercado um método de contenção física para bovinos que propõe a utilização de um aparelho que funciona com ondas eletromagnéticas de baixa intensidade promovendo imobilização sem estresse e ou estímulo doloroso para o animal. O objetivo deste projeto foi avaliar os parâmetros cardiorrespiratórios e hemogasométricos bem como os níveis de cortisol de bovinos submetidos à imobilização eletromagnética, a fim de observar se tal método é eficaz na diminuição do estresse e/ou estímulo doloroso. Foram utilizados 6 bovinos, mestiços, peso médio de 300,3 kg (±85,76). Os animais foram alocados aleatoriamente em dois grupos (controle dele mesmo): grupo controle (GC), introdução da sonda via retal (desligada); grupo Imobilizador (GI) introdução da sonda e permanência desta ligada por 5 minutos. Análise estatística utilizou o Teste T pareado entre os grupos (P<0,05) e a avaliação entre tempos dentro de cada grupo análise de variância de uma única via com repetições múltiplas (ANOVA - RM). Momentos avaliados M0: basal; M1: imediatamente após a retirada da sonda; M2 e M3 (30 e 60 minutos após M1 respectivamente). Houve um aumento significativo nas variáveis: frequências cardíaca e respiratória em (M1), na Pressão arterial média (M1, M2, M3) e níveis de cortisol nos momentos M1 e M2 no grupo imobilizador quando comparado ao grupo controle. Com relação à resposta ao estímulo, o GI teve resposta negativa no momento da estimulação, comparado ao GC (resposta máxima). De acordo com os resultados obtidos, podemos concluir que o imobilizador eletromagnético é um método, exclusivamente, de contenção física, não oferecendo nenhum suporte anestésico, para o conforto ou bem estar ao animal.

The ways of immobilization generally used in cattle provide excessive manipulation and stress for the animal. The pain is an emotional experience and unpleasant sensation in combination with tissue damage. The new method of physical restraint for cattle uses low intensity electromagnetic waves, promising immobilization without stress or painful stimulation for the animals. The aim of this study is to evaluate of cardiorespiratory effects and plasmatic cortisol concentration of cattle submitted to electromagnetic immobilization. Six healthy cows with average weight of 300.3 ± 85.76 kg (mean ± SD) were assigned to two treatments in a randomized design with a 15-day interval between experiments GC (control group) and GI (immobilization group). Data are presented as mean + SD. The statistical analyses used the t-Test between groups, and ANOVA random block design between times into same group. All statistical analyses were performed using P<0.05 as a significant level. Evaluation moments: M1 (basal); M1: after withdrawal probe, M2 and M3 (30 and 60 minutes after M1 respectively). There was a significant increase of FC and f in M1, PAM in the moments (M1, M2, M3) and in the levels of plasmatic cortisol concentration in M1 e M2 in the immobilization group when to compared with the control group. It could be concluded that this electromagnetic immobilization is a method of physic restraint only, offers no anesthetic support and favors comfort and animal welfare.

Effect of remifentanil on requirements for propofol administered by use of a target-controlled infusion system for maintaining anesthesia in dogs.

OBJECTIVE: To evaluate the effect of remifentanil administered by use of a constant rate infusion on the predicted plasma concentration (Cp(predicted)) of propofol required to prevent awareness in 50% of anesthetized dogs (Cp50(predicted)). ANIMALS: 6 healthy dogs. PROCEDURES: Each dog received 2 treatments (1-week interval): induction and maintenance of anesthesia with propofol alone and induction of anesthesia with propofol and maintenance of anesthesia by use of propofol and a constant rate infusion of remifentanil (0.3 microg/kg/min). To induce anesthesia, propofol was administered by use of a target-controlled infusion system to achieve Cp(predicted) of 6.0 microg/mL. Propofol Cp(predicted) was adjusted in 0.5 microg/mL increments or decrements; the motor response to a supramaximal electrical nociceptive stimulus was assessed after each change to determine Cp50(predicted) (mean of the highest Cp(predicted) at which gross purposeful movement was detected in response to stimulation and the lowest Cp(predicted) at which such movement was not detected). RESULTS: Mean +/- SD duration of anesthesia for dogs receiving propofol (148 +/- 35 minutes) and dogs receiving propofol-remifentanil treatment (141 +/- 28 minutes) did not differ. Overall mean propofol Cp(predicted) for induction of anesthesia was 6.0 +/- 0.5 microg/mL. For maintenance of anesthesia, propofol Cp50(predicted) was significantly reduced following addition of remifentanil to the protocol (2.0 +/- 0.5 microg/mL vs 0.9 +/- 0.4 microg/mL; 55% decrease). CONCLUSIONS AND CLINICAL RELEVANCE: In nonpremedicated dogs, propofol Cp50(predicted) of 6.0 microg/mL may be recommended for induction of anesthesia. Propofol requirements for maintaining target-controlled infusion system-based anesthesia were reduced via infusion of remifentanil at a rate of 0.3 microg/kg/min.

Use of bispectral index to monitor depth of anesthesia in isoflurane-anesthetized dogs.

OBJECTIVE: To evaluate the correlation between the bispectral index (BIS) and end-tidal isoflurane (ET(ISO)) concentration and compare the use of 3 BIS sensor positions in dogs. ANIMALS: 6 adult dogs. PROCEDURES: Mechanically ventilated dogs received pancuronium, and depth of anesthesia was altered by increasing ET(ISO) concentration from 1.5% to 2.3% and 3.0%. The BIS, suppression ratio (relative percentage of isoelectric electroencephalographic waveforms), and signal quality index (SQI) were recorded at each ET(ISO) concentration for each of 3 BIS sensor positions (frontal-occipital, bifrontal, and frontal-temporal positions). RESULTS: The BIS and ET(ISO) concentration were poorly correlated; regardless of sensor positioning, mean BIS values did not change significantly as ET(ISO) was increased. At 3% isoflurane, regardless of sensor positioning, there was an increase in suppression ratio coincident with BIS < 40 in some dogs, whereas paradoxic increases in BIS (> 60) were recorded in others. Furthermore, at 3.0% isoflurane, the SQI was significantly lower for the bifrontal sensor position (compared with values for the other positions), but low SQI values prevented recording of BIS values from the frontal-occipital sensor position in 2 dogs. Overall, BIS values derived from the 3 sensor positions did not differ. CONCLUSIONS AND CLINICAL RELEVANCE: In dogs, BIS values may not reflect changes in depth of isoflurane anesthesia in the absence of noxious stimulation. Of the 3 sensor positions, frontal-temporal positioning provided better correlation with changes in depth of anesthesia induced via changes in isoflurane concentrations. However, the sensor placements yielded similar results at SQI values > 50.

Cardiopulmonary effects of buprenorphine in horses.

OBJECTIVE: To investigate the effects of buprenorphine on cardiopulmonary variables and on abdominal auscultation scores in horses. ANIMALS: 6 healthy adult horses. PROCEDURES: Horses were restrained in stocks and allocated to 2 treatments in a randomized crossover design, with 1-week intervals between each treatment. Saline (0.9% NaCl) solution was administered IV as a control, whereas buprenorphine (10 mug/kg, IV) was administered to the experimental group. Cardiopulmonary data were collected for 120 minutes after buprenorphine or saline solution administration. Abdominal auscultation scores were monitored for 2 and 12 hours after drug administration in the control and experimental groups, respectively. RESULTS: Following control treatment, horses remained calm while restrained in the stocks and no significant changes in cardiopulmonary variables were observed throughout the study. Buprenorphine administration caused excitatory phenomena (restlessness and head shaking). Heart rate, cardiac index, and arterial blood pressure were significantly increased after buprenorphine administration until the end of the observational period (120 minutes). Minimal changes were found in arterial blood gas tensions. Abdominal auscultation scores decreased significantly from baseline for 4 hours after buprenorphine administration. CONCLUSIONS AND CLINICAL RELEVANCE: Buprenorphine induced excitement and hemodynamic stimulation with minimal changes in arterial blood gas tensions. These effects may impact the clinical use of buprenorphine in horses. Further studies are indicated to investigate the effects of buprenorphine on gastrointestinal motility and fecal output.