Anestesia total intravenosa em cães e gatos com propofol e suas associações

Total intravenous anesthesia (TIVA) is a technique that has been used more frequently in small animals. Its use has been motivated by the introduction of new drugs with shorter and faster onset action, and by the improving of the infusion bombs. TIVA presents some advantages such as: no environment pollution; it does not demand great investment in the acquisition of specific equipment as for the accomplishment of inhalatory anesthesia; hemodynamic stability and a reduction in the adrenergic response by the surgical stimulation. On the other hand, it also presents some limitations such as: the need of a vein catheterization for the infusion; it’s contraindicated in animals that possess hepatic or renal failure; and it has the necessity of different infusion bombs for each drug used. This technique can be carried out using bombs or equips, in bolus or for continuous rate infusion (CRI) and more recently through modern techniques of targetcontrolled infusion (TCI). Propofol is the most used hypnotic agent drug, being associated with analgesic agents as opioids (extreme-shortness duration), ketamine and/or lidocaine. Differently of what happens with dogs, there is little information about the pharmacokinetic of propofol in cats, which have important differences regarding to the biotransformation of some drugs. Some studies have been carried out in dogs and cats aiming to evaluate the effects caused by propofol and the other agents in CRI, but more studies are still needed, so that these protocols can be used with security in anesthetic practice as an alternative to the inhalatory anesthesia.A anestesia total intravenosa (TIVA) é uma técnica que tem sido preconizada na prática anestésica em pequenos animais. Ela vem sendo empregada, motivada pela introdução de novos fármacos de ações mais curtas e rápidas, além do aperfeiçoamento das bombas de infusão. A TIVA possui algumas vantagens como ausência de poluição ambiental, não exige grande investimento na aquisição de aparelhagem específica como para a realização da anestesia inalatória, estabilidade hemodinâmica e redução na resposta adrenérgica ao estímulo cirúrgico. Por outro lado, apresenta limitações como: necessidade de cateterização de uma veia somente para a infusão, necessidade de diferentes bombas de infusão para cada fármaco utilizado; e contra-indicação em animais que possuam comprometimento hepático ou renal. Esta técnica pode ser realizada através de bombas ou equipo, em bolus ou por infusão contínua e mais recentemente através de modernas técnicas de infusão alvo-controlada. O propofol é o fármaco mais utilizado em Medicina Veterinária como agente hipnótico, estando associado a agentes analgésicos como opióides de ultra-curta duração, cetamina e lidocaína. Diferentemente do que ocorre no cão, há poucas informações relativas à farmacocinética do propofol em felinos, pois estes possuem diferenças importantes em relação à biotransformação dos fármacos. Temse demonstrado através de estudos que o uso isolado de propofol em infusão contínua causa maior depressão cardiorrespiratória. No entanto, quando associado com agentes analgésicos, é possível reduzir a taxa de infusão, minimizando assim estes efeitos colaterais. Essa técnica tem-se demonstrado segura e prática, apesar de ainda existirem controvérsias sobre os efeitos no sistema cardiovascular e respiratório

Seasonal variation of Boophilus microplus on the Santa Catarina Plateau

Durante o período de março de 1979 a fevereiro de 1982 um grupo de doze bovinos adultos da raça Flamenga foram mantidos em um mesmo potreiro com pastagem nativa, sem banhos carrapaticidas. A cada quinze dias foram contadas, de um lado do corpo de cada um dos bovinos, todas as partenóginas e teleóginas ingurgitadas. Ao mesmo tempo foram tomadas as médias mensais de temperaturas e umidade relativa do ar. As infestações nos bovinos apresentaram-se em baixos níveis de agosto a novembro sendo que as mais significantes intensidades de infestações foram verificadas de janeiro a abril. Esta flutuação estacional apresentou, através da análise de regressão linear simples, uma forte semelhança entre os três anos (superior a 76%). During the period from March 1979 to February 1982, a group of twelve adult Flemish cattle was maintained in the same padock with native pasture, without tick dipping. Every fifteen days, the young and engorged female stages on the right side of each animal were counted. At the same time, mean monthly temperatures and humidity were recorded. The infestations on the animal showed low levels in the months of August and November, while the most significant infestation intensities were recorded from January to April. This seasonal fluctuation showed, by simple linear regressive analysis a strong similarity between the three years (superior to 76%).

Determination of the Minimum Alveolar Concentration (MAC) of Isoflurane and Sevoflurane in Callithrix penicillata

Background: The minimum alveolar concentration (MAC) is a measure of quantitative anesthetic potency and has become the standard index for the evaluation and comparison of volatile anesthetics, in addition to guiding dose administration. Black-tufted marmosets (Callithrix penicillata) are primates present in the clinical and surgical routine of veterinary hospitals, as well as experimental models, especially in neuroscience. Few studies have evaluated the potency of the main volatile anesthetics in this species. This study aimed to determine the MAC of isoflurane and sevoflurane in C. penicillata using the up-and-down method and to evaluate the effects of these drugs on the quality of anesthetic induction, maintenance, and recovery. Materials, Methods & Results: Twenty-four animals of undetermined age were used. All marmosets were healthy according to hematological and physical evaluation. The animals were randomly divided into 2 groups: ISOMAC and SEVOMAC. Each animal was induced to general anesthesia in an anesthetic box with oxygen (5 L/min) and sevoflurane at 7% in the SEVOMAC group or isoflurane at 5% in the ISOMAC. Upon reaching lateral decubitus, orotracheal intubation was performed. General anesthesia was maintained with isoflurane or sevoflurane diluted in oxygen (0.8 L/min) using a non-rebreathing delivery system under spontaneous ventilation. As defined in the pilot study, the first animal from ISOMAC started the maintenance of anesthesia with 2.6% isoflurane, while the first animal in SEVOMAC received 4% sevoflurane. After finishing the instrumentation to assess heart rate, respiratory rate, systolic blood pressure, pulse oximeter oxygen saturation, end-tidal carbon dioxide concentration, and rectal temperature, a 15-min wait to reach anesthetic equilibrium was allowed, and then an electrical noxious stimulation (50 mA and 50 Hz) was performed on the lateral aspect of the thigh (a faradic current of 3 consecutive single stimuli, followed by 2 continuous stimuli). The animals' responses to the electrical stimulus were observed. The presence of a positive response (gross movement of the limbs, head, or vocalization) or a negative response (absence of gross movements) determined the increase or reduction, respectively, of the inhalation anesthetic concentration by 10% in the subsequent marmoset. The quality of anesthetic induction and recovery from anesthesia was evaluated using a scale that measured the intensity of agitation, coughing, nausea, and vomiting. Physiological variables were recorded before (M0) and after (M1) applying the nociceptive stimulus. Isoflurane and sevoflurane MAC values in C. penicillata were 2.29 ± 0.10% and 3.93 ± 0.61 % respectively. Physiological parameters, quality of anesthetic induction and recovery did not differ significantly between groups. However, isoflurane caused irritation of the airway and ocular mucous membranes, more coughing episodes, and tearing at induction. There was no difference between groups for time to extubation and recovery time to regain sternal position. Discussion: Previous studies in primates found lower MAC values for both anesthetics, except for Lemur catta. Those findings may be explained by the use of different nociceptive stimuli and the MAC determination method employed, although no differences in MAC values have been described between bracketing or up-and-down methods in human primates and dogs. It is unlikely that the stimulus and technique alone are the determining factors for the high concentration of isoflurane and sevoflurane observed in the present study since MAC was high with both halogenates, indicating that dose extrapolation from other species can lead to the wrong anesthetic dosage. Keywords: Callithrix penicillata, marmoset, isoflurane, sevoflurane, minimum alveolar concentration (MAC).Background: The minimum alveolar concentration (MAC) is a measure of quantitative anesthetic potency and has become the standard index for the evaluation and comparison of volatile anesthetics, in addition to guiding dose administration. Black-tufted marmosets (Callithrix penicillata) are primates present in the clinical and surgical routine of veterinary hospitals, as well as experimental models, especially in neuroscience. Few studies have evaluated the potency of the main volatile anesthetics in this species. This study aimed to determine the MAC of isoflurane and sevoflurane in C. penicillata using the up-and-down method and to evaluate the effects of these drugs on the quality of anesthetic induction, maintenance, and recovery. Materials, Methods & Results: Twenty-four animals of undetermined age were used. All marmosets were healthy according to hematological and physical evaluation. The animals were randomly divided into two groups: ISOMAC and SEVOMAC. Each animal was induced to general anesthesia in an anesthetic box with oxygen (5 L/min) and sevoflurane at 7% in the SEVOMAC group or isoflurane at 5% in the ISOMAC. Upon reaching lateral decubitus, orotracheal intubation was performed. General anesthesia was maintained with isoflurane or sevoflurane diluted in oxygen (0.8 L/min) using a non-rebreathing delivery system under spontaneous ventilation. As defined in the pilot study, the first animal from ISOMAC started the maintenance of anesthesia with 2.6% isoflurane, while the first animal in SEVOMAC received 4% sevoflurane. After finishing the instrumentation to assess heart rate, respiratory rate, systolic blood pressure, pulse oximeter oxygen saturation, end-tidal carbon dioxide concentration, and rectal temperature, a 15-minute wait to reach anesthetic equilibrium was allowed, and then an electrical noxious stimulation (50 mA and 50 Hz) was performed on the lateral aspect of the thigh (a faradic current of 3 consecutive single stimuli, followed by 2 continuous stimuli). The animals' responses to the electrical stimulus were observed. The presence of a positive response (gross movement of the limbs, head, or vocalization) or a negative response (absence of gross movements) determined the increase or reduction, respectively, of the inhalation anesthetic concentration by 10% in the subsequent marmoset. The quality of anesthetic induction and recovery from anesthesia was evaluated using a scale that measured the intensity of agitation, coughing, nausea, and vomiting. Physiological variables were recorded before (M0) and after (M1) applying the nociceptive stimulus. Isoflurane and sevoflurane MAC values in C. penicillata were 2.29 ± 0.10% and 3.93 ± 0.61% respectively. Physiological parameters, quality of anesthetic induction and recovery did not differ significantly between groups. However, isoflurane caused irritation of the airway and ocular mucous membranes, more coughing episodes, and tearing at induction. There was no difference between groups for time to extubation and recovery time to regain sternal position. Discussion: Previous studies in primates found lower MAC values for both anesthetics, except for Lemur catta. Those findings may be explained by the use of different nociceptive stimuli and the MAC determination method employed, although no differences in MAC values have been described between bracketing or up-and-down methods in human primates and dogs. It is unlikely that the stimulus and technique alone are the determining factors for the high concentration of isoflurane and sevoflurane observed in the present study since MAC was high with both halogenates, indicating that dose extrapolation from other species can lead to the wrong anesthetic dosage

Uncovered stent does not provoke reactions in renal arteries and renal parenchyma in swines

OBJECTIVE: To assess the histological changes of the aorta, the renal arteries and the renal parenchyma in swine, induced by a metalic uncovered stent implanted in transrenal position in the abdominal aorta. METHODS: Ten pigs with a mean weight of 86.6 kg and mean age of 6 months underwent implantation of metal stent graft placed in the aorta at the level of the renal arteries after 100 days of implantation. The self-expanding stents were released by laparotomy. Anatomic and histological analyses of the abdominal aorta, the renal arteries and the renal parenchyma were performed. Histological slices were performed in the following sites: 1) transitional zone between the aorta with and without stent graft; 2) portion of the renal arteries ostia; 3) renal parenchyma. The slices were stained through the hematoxylin and eosin stain technique and analyzed according the protocol of histological analyses applied in the clinical practice of pathology labs. RESULTS: The macroscopic findings showed thickening of the aortic wall; patent renal arteries; and normal anatomic renal structures. Microscopic analyses, close to the stents, showed thickening of the vascular wall, renal arteries without changes, and preserved renal parenchyma. CONCLUSION: The uncovered stainless steel stent caused a significant inflammatory reaction with thickening of the aortic wall. However, the renal arteries remained patent and the renal parenchyma did not present embolic or ischemic changes.OBJETIVO: Avaliar as alterações histológicas da aorta, artéria renal e parênquima renal, em suínos, induzidos pelo stent metálico descoberto implantado em localização transrenal na aorta abdominal. MÉTODOS: Foram utilizados 10 suínos com peso médio de 86,6 quilos e idade média de 6 meses, submetidos a implante de stent metálico posicionado na aorta, no nível das artérias renais, após 100 dias do implante. Os stents foram liberados por auto-expansão com laparotomia. Foram realizadas análises anatômicas e histológicas da aorta abdominal, artérias renais e parênquima renal. Os cortes histológicos foram realizados nos seguintes locais: 1) transição entre a aorta normal e aorta contendo stent; 2) porção contendo os óstios das artérias renais, 3) parênquima renal. As lâminas foram coradas pela técnica da hematoxilina e eosina e analisadas conforme protocolo de análise histológica aplicada na prática clínica dos laboratórios de patologia. RESULTADOS: Os achados macroscópicos revelaram espessamento da parede aórtica; artérias renais pérvias; estrutura anatômica renal normal. Análises microscópicas, próximas aos stents, evidenciaram espessamento da parede vascular, artérias renais sem alterações e parênquima renal preservado. CONCLUSÃO: O stent de aço inoxidável descoberto produziu importante reação inflamatória com espessamento da parede da aorta. No entanto, as artérias renais permaneceram pérvias e o parênquima renal sem alterações isquêmicas ou embólicas.INCOR Hospital Maternidade Marieta Konder BonhausemUNIFESPUNIFESP - Escola Paulista de Medicina São PauloUniversidade do Estado de Santa Catarina Hospital VeterinárioLaboratório RochaHospital São JoséSanta CasaUNIFESP, EPMSciEL

Embriões bovinos PIV vitrificados em diferentes soluções crioprotetoras com ou em o uso de nitrogênio super-resfriado

O total aproveitamento de embriões PIV ainda depende de uma metodologia eficiente de criopreservação. Este estudo avaliou a taxa de eclosão de embriões bovinos PIV, vitrificados em OPS usando três diferentes soluções crioprotetoras (Experimento 1) e o emprego de nitrogênio normal (-196°C) ou super-resfriado (-210°C) (Experimento 2). No primeiro experimento (12 repetições) 576 blastocistos expandidos (Bx) PIV foram aleatoriamente alocados em 4 grupos: G1 (20% EG + 20% DMSO), G2 (25% EG + 25% GLI), G3 (20% EG + 20% PRO) e G4 (controle não vitrificado). Após 72 horas de cultivo in vitro, a taxa de eclosão do grupo controle (84,0%) foi superior às observadas nos grupos vitrificados (

Arterial, Mixed Venous or Central Venous Hemogasometry and End Tidal CO2 in Dogs under Different Hemodynamic States

Background: Hemogasometric analysis is used in the interpretation of acid-base balance (ABB) and to access pulmonary ventilation. Already mixed venous oxygen saturation obtained at pulmonary artery correlates with tissue oxygenation. However, both samples can be difficult to access because of the difficulties in arterial and pulmonary catheterization. The aim of this study was to evaluate the feasibility of replacing the arterial and mixed venous bloods, the end tidal pressure of carbon dioxide (EtCO2) and central venous blood in the analysis of pulmonary ventilation, tissue oxygenation and ABB in dogs under different hemodynamic states.Material, Methods & Results: Nine dogs were used with an average weight of 19.6 ± 1.3 kg, anesthetized with isoflurane at 1.4 V% diluted on oxygen 60% (Baseline), and subsequently undergoing mechanical ventilation (MV) and the hypodinamic state (Hypo) with isoflurane at 3.5V% and mean arterial pressure (MAP) lower than 50 mmHg and hyperdynamic state (Hyper) by dobutamine infusion at 5 μg/kg/min and with MAP 30% higher than baseline. For each time allowed a 15 min of stabilization by each hemodynamic status. Simultaneously were collected samples of 0.6 mL of arterial blood by metatarsal artery, mixed and central venous blood by pulmonary artery and right atrium for hemogasometric analysis. To access lung function we correlated and compared the EtCO2 values obtained by gas analyzer with expired carbon dioxide pressure in the arterial blood (PaCO2), mixed venous blood (PmvCO2) and central venous blood (PcvCO2). For the interpretation of tissue oxygenation we correlated and compared the values of mixed (SmvO2) and central (ScvO2) venous oxygen saturation. For the acid-base balance we used the correlation of potencial hydrogen (pH); carbon dioxide pressure (PCO2); bicarbonate ion (HCO3-); base excess (BE); anion GAP (AG); sodium ions (Na+), chlorine ions (Cl-), potassium ions (K+) and ionized calcium (iCa) of arterial (a) mixed venous (mv) and central venous (CV) bloods. Statistical analysis was performed using ANOVA-RM followed by Dunnet test for differences between times and Tukey’s test for differences among the samples (P ≤ 0.05). Pearson correlation analysis was performed using linear regression and for comparison methods we used the Bland-Altman analysis The EtCO2 values correlated (r = 0.87) and were according to Bland-Altman analysis with PaCO2 values (mean difference of -1.6 ± 2,9 mmHg for PaCO2. There were no differences (P ≤ 0.05) from SmvO2 and ScvO2. ScvO2 correlated (r = 0.91) with SmvO2 at different hemodynamic states and with a mean difference of -0.4 ± 2.5%. Both venous bloods were correlated with the analysis of arterial blood acid-base balance and electrolytes in different hemodynamic states. However, the ionized calcium levels were 40% lower in arterial blood.Discussion: EtCO2 measurement depends of monitor technology and proper pulmonar ventilation and perfusion. In this study the limiting factor in replacing the PaCO2 hair EtCO2 was spontaneous ventilation because in this state pulmonary ventilation is compromissed. With the use of MV was possible get up similar results in the pulmonar function analysis using the EtCO2 and PaCO2. The use of central venous blood instead mixed venous blood at oxygen saturation analysis provided adequate estimate this parameter. This being easier and less invasive technique. ABB was possible with all samples with own reference values for venous and arterial samples. This is an interesting result for critical patients where the arterial sample is difficult. In electrolytes the sample was indifferent except for calcium because pH interfere in this values. It was conclude that the values of EtCO2 and central venous blood are correlated and can replace arterial and mixed venous bloods in the analysis of lung function, tissue oxygenation and acid base balance