Hemodynamic and respiratory effects of positive end-expiratory pressure during a pulmonary distress model in isoflurane anesthetized swine

Background: Several pulmonary and hemodynamic complications may occur during mechanical ventilation of the lungs. The use of a positive end-expiratory pressure (PEEP) can improve oxygenation and prevent atelectasis, although this method can cause important hemodynamic side effects. Mostly, these hemodynamic effects are due to increased airway pressure that is transferred to the intrapleural space, increasing the intrathoracic pressure, which decreases venous return to the heart. Cardiac output is significantly reduced with high PEEP levels which in turn precludes the improvement effects on blood oxygenation. The aim of this study was to evaluate hemodynamic and respiratory effects of different levels of carbon dioxide insufflations associated with different levels of PEEP under conventional two-lung ventilation in isoflurane anesthetized pigs.Materials, Methods & Results: Twelve juvenile pigs were anesthetized with ketamine and midazolam, and end tidal isoflurane 2.0 V% for maintenance. Animals were submitted to tension pneumothorax through an acute intrathoracic insufflation with carbon dioxide at 0, 5, and 10 mmHg. Mechanical lung ventilation with 100% oxygen was started with zero PEEP then increased to 5 and 10 cmH2 O. Ventilatory, respiratory and hemodynamic parameters were measured, as well as blood gases. Tension pneumothorax of 10 mmHg, with both PEEP levels, induced...(AU)

Hemodynamic and respiratory effects of positive end-expiratory pressure during a pulmonary distress model in isoflurane anesthetized swine

Background: Several pulmonary and hemodynamic complications may occur during mechanical ventilation of the lungs. The use of a positive end-expiratory pressure (PEEP) can improve oxygenation and prevent atelectasis, although this method can cause important hemodynamic side effects. Mostly, these hemodynamic effects are due to increased airway pressure that is transferred to the intrapleural space, increasing the intrathoracic pressure, which decreases venous return to the heart. Cardiac output is significantly reduced with high PEEP levels which in turn precludes the improvement effects on blood oxygenation. The aim of this study was to evaluate hemodynamic and respiratory effects of different levels of carbon dioxide insufflations associated with different levels of PEEP under conventional two-lung ventilation in isoflurane anesthetized pigs.Materials, Methods & Results: Twelve juvenile pigs were anesthetized with ketamine and midazolam, and end tidal isoflurane 2.0 V% for maintenance. Animals were submitted to tension pneumothorax through an acute intrathoracic insufflation with carbon dioxide at 0, 5, and 10 mmHg. Mechanical lung ventilation with 100% oxygen was started with zero PEEP then increased to 5 and 10 cmH2 O. Ventilatory, respiratory and hemodynamic parameters were measured, as well as blood gases. Tension pneumothorax of 10 mmHg, with both PEEP levels, induced...

Effects of detomidine constant rate infusion on blood glucose and lactate in devoflurane anesthetized horses

Background: The drugs that promote sedation, analgesia, and anesthesia, as inhalatory agents, phenothiazines, benzodiazepines, alpha-2 adrenergic agonists, and opioids, can promote different kinds of side effects. The concept of a balanced anesthesia in equine was developed in order to minimize adverse effects inherent to anesthesia, creating a combination of lower doses of these drugs in comparison with the doses of each one used alone. Alpha-2-adrenoceptor agonists such as xylazine, detomidine, and others, are drugs used for standing sedation, analgesia, and reduction of volatile anesthetic requirement in the equine as well as an agent used to maintenance of arterial blood pressure during anesthesia. Alpha-2 agonists works stimulating receptors of autonomic neurons inducing reduction of heart rate, cardiac output and vascular resistance, hypertension, behavioral changes, and inhibition of insulin secretion. This reduction in insulin levels increases blood glucose concentration in horses due to its lower utilization in insulin-dependent tissues, as muscular and adipose tissues. Muscular tissue is capable to maintain a constant lactate production even in a well oxygenated environment in order to maintain its cellular activity, especially in cases when glucose is not available. To evaluate the effect on blood glucose and lactate, horses were submitted to one hour of detomidine constant rate infusion during sevoflurane inhalatory anesthesia with controlled ventilation, in order to assess blood concentration of glucose and lactate. Materials, Methods & Results: Four adult horses were studied. Detomidine 20 µg.kg-¹ was used as premedication followed by an association of ketamine and diazepam intravenously as anesthetic induction. After intubation, sevoflurane was vaporized at approximately 2.3 V%. Mechanical ventilation was established. After stabilization, an intravenous continuous rate infusion (CRI) of detomidine 5 µg.kg.h-¹ was started. Venous blood samples were collected before premedication, prior to detomidine continuous infusion, 20, 40, and 60 min after beginning of infusion, in order to determination of glucose and lactate serum concentrations. After 60 min of detomidine infusion, the horses were allowed to recovery. There was statistical significant hyperglycemia in the horses under CRI of detomidine. There was no significant increase in blood lactate, despite of the hyperlactatemia in some animals. Discussion: Detomidine CRI of 5 µg.kg.h-¹ does increase blood glucose levels over normal values but not to levels that could be toxic to tissues, mainly CNS. With low levels of serum insulin, body tissues, mainly muscular and adipose tissues, are unable to capture this available blood glucose and these cells depend on lactate metabolism. The lactate serum concentrations below normal range observed in studied horses suggest that all lactate produced by the tissues is being utilized in the energetic metabolism. In according to many authors, lactate is produced and utilized for mitochondrias as energetic source even in fully oxygenated tissues, which seems to be what happened in this experiment. The present study helps to understand energetic metabolism in horses under general inhaled anesthesia with detomidine CRI, a selective alpha-2-adrenoceptor agonist. In order to better evaluate energetic metabolism during inhaled anesthesia under detomidine influence, other studies are suggested, as prolonged anesthesia duration to evaluate a longer adrenergic stimulus induced by detomidine. Besides, other investigations with detomidine CRI in horses submitted to surgical procedures could provide different responses in energetic metabolism.

Tempo de sobrevida de cães com imagemradiográfica compatível com neoplasia ósseano esqueleto apendicular, sem o usode quimioterapia / Survival times of dogs with compatible image of bone neoplasms from appendicular skeleton by the radiographic examination

O osteossarcoma é a neoplasia maligna óssea primária mais diagnosticada no cão, correspondendo a mais de 85% dos tumores ósseos. O tratamento preconizado é a cirurgia radical de amputação do membro acometido, associada à quimioterapia. No Hospital de Clíni¬cas Veterinárias da Universidade Federal do Rio Grande do Sul (HCV-UFRGS) foram analisa¬dos 23 cães que apresentavam imagem radiográfica compatível com neoplasia óssea no esque¬leto apendicular. Avaliou-se a evolução destes animais, cujos proprietários optaram por não realizar quimioterapia. Destes, 16 optaram por não realizar a amputação, utilizando somente analgésicos, 5 optaram pela cirurgia e 2 por eutanásia no momento do diagnóstico. A sobrevida média foi de 3,8 meses, sendo 3,4 meses para os cães tratados apenas com analgésicos e 4,9 meses para os cães tratados apenas com a amputação

Osteosarcoma is the most common primary bone tumor in dogs accounting for up to 85% of malignancies originating in the skeleton. The main treatment is amputation associated with chemotherapy. At Veterinary Hospital of Federal University of Rio Grande do Sul were analyzed 23 dogs with compatible image of bone neoplasms by the radiographic examination from appendicular skeleton. Through telephone contacts it was possible to evaluate these animals evolution, whose owners chose not to use the chemotherapy. Sixteen owners opted to treat just with analgesics, five opted for the surgery and two dogs were euthanized at the moment of the diagnostic. The mean survival times was 3,8 months, being 3,4 months of the dogs without surgery and 4,9 months of the dogs treated with surgery alone

Tempo de sobrevida de cães com imagemradiográfica compatível com neoplasia ósseano esqueleto apendicular, sem o usode quimioterapia / Survival times of dogs with compatible image of bone neoplasms from appendicular skeleton by the radiographic examination

O osteossarcoma é a neoplasia maligna óssea primária mais diagnosticada no cão, correspondendo a mais de 85% dos tumores ósseos. O tratamento preconizado é a cirurgia radical de amputação do membro acometido, associada à quimioterapia. No Hospital de Clíni¬cas Veterinárias da Universidade Federal do Rio Grande do Sul (HCV-UFRGS) foram analisa¬dos 23 cães que apresentavam imagem radiográfica compatível com neoplasia óssea no esque¬leto apendicular. Avaliou-se a evolução destes animais, cujos proprietários optaram por não realizar quimioterapia. Destes, 16 optaram por não realizar a amputação, utilizando somente analgésicos, 5 optaram pela cirurgia e 2 por eutanásia no momento do diagnóstico. A sobrevida média foi de 3,8 meses, sendo 3,4 meses para os cães tratados apenas com analgésicos e 4,9 meses para os cães tratados apenas com a amputação(AU)

Osteosarcoma is the most common primary bone tumor in dogs accounting for up to 85% of malignancies originating in the skeleton. The main treatment is amputation associated with chemotherapy. At Veterinary Hospital of Federal University of Rio Grande do Sul were analyzed 23 dogs with compatible image of bone neoplasms by the radiographic examination from appendicular skeleton. Through telephone contacts it was possible to evaluate these animals evolution, whose owners chose not to use the chemotherapy. Sixteen owners opted to treat just with analgesics, five opted for the surgery and two dogs were euthanized at the moment of the diagnostic. The mean survival times was 3,8 months, being 3,4 months of the dogs without surgery and 4,9 months of the dogs treated with surgery alone(AU)