Influence of recumbency on the pulmonary shunt in sevoflurane-anaesthetised sheep / Influência do decúbito na ocorrência de shunt pulmonar em ovinos anestesiados com sevoflurano

This study assessed the impact of different recumbency on sevoflurane-anaesthetised sheep. Seven female sheep were premedicated with 0.1 mg.kg-1 butorfanol and subsequently administered a combination of 3 mg.kg-1 ketamine and 0.5 mg.kg-1 midazolam. Animals were maintained on sevoflurane anaesthesia with pressure-controlled ventilation (12 cm H2O peak inspiratory pressure) and ƒ of 10 mpm. During the anaesthetic procedure, animals underwent one out of three different recumbency: dorsal, left lateral, or right lateral positions. Treatments lasted 120 min with a 48-h washout period in between the treatments. Arterial and central venous blood samples were withdrawn for blood gas and electrolytes analysis and pulmonary shunt fraction (Qs/Qt) CaO2, CcvO2, and CcO2 were calculated accordingly. Results showed that Qs/Qt greatly decreased from 0 to 120 min in all the groups (dorsal: 69.3% to 27.3%; left lateral: 59.1% to 25.0%; right lateral: 67.2% to 32.4%). CaO2, CcvO2 and CcO2 improved over time points, with no difference among treatments. PaO2 and PAO2 showed higher values for 60 and 120 min compared to the 0 min value in all groups, with no differences among treatments as well. PaCO2 and ETCO2 in the lateral groups were higher than those in the dorsal group at 120 min. Pressure-controlled ventilation improved gas exchanges in sheep, thereby reducing pulmonary shunt. Recumbency did not interfere with pulmonary shunt, nevertheless, special attention must be paid to lateral recumbency.

O estudo avaliou o impacto de diferentes decúbitos em ovelhas anestesiadas com sevoflurano. Sete ovelhas foram pré-medicadas com 0,1 mg.kg-1 de butorfanol e induzidas à anestesia com 3 mg.kg-1 de cetamina e 0,5 mg.kg-1 de midazolam. Os animais foram mantidos em anestesia por sevofluorano, em ventilação mecânica controlada por pressão, com pico inspiratório em 12 cm H2O e f de 10 mpm, sendo mantidos por 120 minutos. Durante esse período os animais foram submetidos a um dos três tratamentos: decúbito dorsal, lateral esquerdo ou lateral direito, com intervalo de no mínimo 48 horas entre eles. Amostras de sangue arterial e venoso central foram colhidas para análise de gases sanguíneos e eletrólitos, bem como para cálculo da fração de shunt pulmonar (Qs/Qt), CaO2, CcvO2 e CcO2. Os resultados mostraram que Qs/Qt diminuiu expressivamente de 0 a 120 minutos em todos os grupos (dorsal: 69,3% para 27,3%; lateral esquerdo: 59,1% para 25,0%; lateral direito: 67,2% para 32,4%). Os índices de CaO2, CcvO2 e CcO2 melhoraram ao longo do tempo, sem diferença entre tratamentos. PaO2 e PAO2 apresentaram valores maiores, em todos os grupos, nos minutos 60 e 120 em comparação ao momento 0, não havendo diferenças entre tratamentos. PaCO2 e ETCO2 apresentaram maiores valores nos grupos laterais em comparação ao grupo dorsal ao final do procedimento. Conclui-se que a ventilação controlada por pressão melhorou as trocas gasosas em ovelhas anestesiadas com sevoflurano, reduzindo o shunt pulmonar. O decúbito não interferiu na formação de shunt pulmonar, porém, deve ser dada atenção especial aos decúbitos laterais.

Efeitos da PEEP na ventilação controlada a volume sobre parâmetros hemodinâmicos em suínos submetidos ao pneumoperitônio associado ao cefalodeclive / Effects of PEEP on hemodynamic variables in pigs submitted to volume-controlled ventilation under pneumoperitoneum associated to cephalodeclive

Videolaparoscopic procedures have gained prominence due to their low invasiveness, causing less surgical trauma and better post-surgical recovery. However, the increase in intra-abdominal pressure due to the institution of pneumoperitoneum can alter the patient's homeostasis. Therefore, volume-controlled ventilation, associated with positive end-expiratory pressure (PEEP), improves arterial oxygenation and prevents pulmonary collapse, but it can lead to important hemodynamic changes. The aim of this study was to evaluate, comparatively, the effects of positive end expiratorypressure (PEEP) on hemodynamic variables of pigs submitted to volume-controlled ventilation, during pneumoperitoneum and maintained in head-down tilt and determine which PEEP value promotes greater stability on hemodynamic variables. Twenty-four pigs were used, between 55 and 65-day-old, weighing between 15 and 25 kg, randomly divided into 3 distinct groups differentiated by positive end-expiratory pressure: PEEP 0 (volume-controlled ventilation and PEEP of 0 cmH2O), PEEP 5 (volume-controlled ventilation and PEEP of 5 cmH2O) and PEEP 10 (volume-controlled ventilation and PEEP of 10 cmH2O). Volume-controlled ventilation was adjusted to 8 mL/kg of tidal volume and a respiratory rate of 25 movements per min. Anesthesia was maintained with continuous infusion of propofol (0.2 mg/kg/min) and midazolam (1 mg/kg/h). Pneumoperitoneum was performed with carbon dioxide (CO2), keeping the intraabdominal pressure at 15 mmHg and the animals were positioned on a 30° head-down tilt. The evaluations of hemodynamic variables started 30 min after induction of anesthesia (M0), followed by measurements at 15-min intervals (from M15 to M90), completing a total of 7 evaluations. The variables of interest were collected over 90 min and submitted to analysis of variance followed by Tukey's post-hoc test, with P < 0.05. The PEEP 10 group had higher values of CVP and mCPP, while the PEEP 5 group, mPAP and PVR were higher. The PEEP 0 group, on the other hand, had higher means of CI. Regarding the moments, there were differences in HR, SAP, DAP, MAP, CO, IC and TPR. According to the literature, important hemodynamic effects due to pneumoperitoneum are reported, which can be caused by the pressure used in abdominal insufflation, CO2 accumulation, duration of the surgical procedure, hydration status and patient positioning. Mechanical ventilation associated with PEEP can also cause an increase in intrathoracic pressure and, therefore, reduce cardiac output. Cardiovascular changes are proportional to the PEEP used. Central venous pressure (PVC) measure the patient's preload, and intrathoracic pressure can interfere with this parameter. The peak pressure values in the PEEP 10 group were higher than the other groups, demonstrating that the increase in intrathoracic pressure results in higher PVC values. Regarding PAPm and PCPm, these variables can be influenced according to the PEEP values and the patient's position. In relation to CI, the increase in PEEP may reflect on intrathoracic pressure, resulting in greater compression of the heart, with a consequent reduction in cardiac output and cardiac index. Therefore, it is concluded that the PEEP effects of 0 cmH2O and 5 cmH2O on hemodynamics are discrete, under the proposed conditions.(AU)

Efeito de frações inspiradas de oxigênio e modalidades ventilatórias diferentes sobre a idade de cães / [Effects of oxygeninspired fractions and different ventilatory modalities on the age of dogs]

Objetivou-se avaliar diferentes modalidades ventilatórias em cães de diferentes idades submetidos à fração inspirada de oxigênio (FiO2) de 40% e 100%. Foram utilizados 36 cães de três grupos etários (GJ: 0-5; GA: 5-10 e GG: 10-15 anos), sem padronização de peso, sexo, raça e procedimento cirúrgico. Foram pré-medicados com acepromazina e morfina (0,02 e 0,5mg/kg), induzidos à anestesia geral com propofol dose-efeito, manutenção do plano anestésico com isoflurano em 1,3 V% e fornecimento de oxigênio conforme a FiO2 estabelecida para o grupo. Os animais foram submetidos a quatro diferentes modalidades ventilatórias: ventilação espontânea (VE), ventilação ciclada a volume (VCV), ventilação ciclada a pressão (VCP) e ventilação ciclada a pressão com PEEP (VCPP), e permaneceram 30 minutos em cada modalidade. Os parâmetros cardiovasculares mantiveram-se estáveis para todas as FiO2, modalidades ventilatórias e idades. Com relação aos parâmetros ventilatórios, na FiO2 100%, foram observados PaCO2 de 45mmHge e 29% de shunt, enquanto a FiO2 40% apresentou PaCO2 de 43 mmHg e 13% de shunt. Em relação às diferentes idades, os animais adultos e geriátricos apresentaram maiores valores de shunt (26% e 22%) e PaCO2 (44mm/Hg e 46mm/Hg). Conclui-se que a fração inspirada de 40% e a modalidade ventilatória ciclada a volume mostraram-se mais eficientes.(AU)

The objective was to evaluate different ventilatory modalities in dogs of different ages submitted to the inspired fraction of oxygen (FiO2) of 40% and 100%. Thirty-six dogs from three age groups (GJ 0-5, GA 5-10 and GG 10-15 years) were used, without standardization of weight, gender, race and surgical procedure. They were premedicated with acepromazine and morphine (0.02 and 0.5mg/kg), induced to general anesthesia with propofol dose/effect, maintenance of the anesthetic plane with isoflurane in 1.3V% and oxygen supply according to FiO2 established for the group. The animals were submitted to 4 different ventilation modalities, spontaneous ventilation (VS), volume-cycled ventilation (VCV), pressure-cycled ventilation (VCP) and pressure-cycled ventilation with PEEP (VCPP) and remained 30 minutes in each modality. The cardiovascular parameters remained stable for all FiO2, ventilatory modalities and ages. Regarding ventilatory parameters, in FiO2 and PaCO2 of 45mmHg and 29% of shunt, in FiO2 100%, PaCO2 of 43mmHg and 13% of shunt were observed. Regarding the different ages, adult and geriatric animals presented higher values of Shunt (26 and 22%) and PaCO2 (44 and 46mmHg). It was concluded that the inspired fraction of 40% and the volume-cycled ventilatory modality were more efficient.(AU)

Efeito de frações inspiradas de oxigênio e modalidades ventilatórias diferentes sobre a idade de cães / [Effects of oxygen inspired fractions and different ventilatory modalities on the age of dogs]

Objetivou-se avaliar diferentes modalidades ventilatórias em cães de diferentes idades submetidos à fração inspirada de oxigênio (FiO2) de 40% e 100%. Foram utilizados 36 cães de três grupos etários (GJ: 0-5; GA: 5-10 e GG: 10-15 anos), sem padronização de peso, sexo, raça e procedimento cirúrgico. Foram pré-medicados com acepromazina e morfina (0,02 e 0,5mg/kg), induzidos à anestesia geral com propofol dose-efeito, manutenção do plano anestésico com isoflurano em 1,3 V% e fornecimento de oxigênio conforme a FiO2 estabelecida para o grupo. Os animais foram submetidos a quatro diferentes modalidades ventilatórias: ventilação espontânea (VE), ventilação ciclada a volume (VCV), ventilação ciclada a pressão (VCP) e ventilação ciclada a pressão com PEEP (VCPP), e permaneceram 30 minutos em cada modalidade. Os parâmetros cardiovasculares mantiveram-se estáveis para todas as FiO2, modalidades ventilatórias e idades. Com relação aos parâmetros ventilatórios, na FiO2 100%, foram observados PaCO2 de 45mmHge e 29% de shunt, enquanto a FiO2 40% apresentou PaCO2 de 43 mmHg e 13% de shunt. Em relação às diferentes idades, os animais adultos e geriátricos apresentaram maiores valores de shunt (26% e 22%) e PaCO2 (44mm/Hg e 46mm/Hg). Conclui-se que a fração inspirada de 40% e a modalidade ventilatória ciclada a volume mostraram-se mais eficientes.(AU)

The objective was to evaluate different ventilatory modalities in dogs of different ages submitted to the inspired fraction of oxygen (FiO2) of 40% and 100%. Thirty-six dogs from three age groups (GJ 0-5, GA 5-10 and GG 10-15 years) were used, without standardization of weight, gender, race and surgical procedure. They were premedicated with acepromazine and morphine (0.02 and 0.5mg/kg), induced to general anesthesia with propofol dose/effect, maintenance of the anesthetic plane with isoflurane in 1.3V% and oxygen supply according to FiO2 established for the group. The animals were submitted to 4 different ventilation modalities, spontaneous ventilation (VS), volume-cycled ventilation (VCV), pressure-cycled ventilation (VCP) and pressure-cycled ventilation with PEEP (VCPP) and remained 30 minutes in each modality. The cardiovascular parameters remained stable for all FiO2, ventilatory modalities and ages. Regarding ventilatory parameters, in FiO2 and PaCO2 of 45mmHg and 29% of shunt, in FiO2 100%, PaCO2 of 43mmHg and 13% of shunt were observed. Regarding the different ages, adult and geriatric animals presented higher values of Shunt (26 and 22%) and PaCO2 (44 and 46mmHg). It was concluded that the inspired fraction of 40% and the volume-cycled ventilatory modality were more efficient.(AU)

Determining the contribution of ventilation and insulation of broiler breeding houses in production performance using Analytic Hierarchy Process (AHP)

This study was conducted using Analytic Hierarchy Process (AHP) in order to rank broiler breeding farms in Zanjan province, Iran, regarding buildings, installations, and equipment to determine their effects on production factors. Data on 108 farms were collected using designed forms. This data was analyzed based on the effectiveness of each parameter in the production and management category according to experts opinion. The results indicated that ventilation systems (fans, inlets, and damper) as well as wall and roof insulation in poultry houses, constituted 66% of the technology coefficient. The stocking density increased through improvement of the mechanization coefficient. Most of these farms used longitudinal or tunnel ventilation and a combination of small and large fans. Roof insulation was mostly done using glass wool, and corrugated plastic while installing the heaters outside the poultry house. In these farms, the use of nipple drinkers and plate feeders was more prevalent. Moreover, the results showed that feed conversion and production indices have a significant correlation with mechanization coefficient so that farms with better mechanization coefficients had lower conversion ratio (p=0.04) and higher production indices (p=0.015). In general, the results indicated that ventilation and air inlet systems, as well as wall and roof building technologies have the greatest influence on the mechanization coefficient, while better mechanization coefficients translated into improvements in production efficiency and economic performance of poultry farms.(AU)

Determining the contribution of ventilation and insulation of broiler breeding houses in production performance using Analytic Hierarchy Process (AHP)

This study was conducted using Analytic Hierarchy Process (AHP) in order to rank broiler breeding farms in Zanjan province, Iran, regarding buildings, installations, and equipment to determine their effects on production factors. Data on 108 farms were collected using designed forms. This data was analyzed based on the effectiveness of each parameter in the production and management category according to experts opinion. The results indicated that ventilation systems (fans, inlets, and damper) as well as wall and roof insulation in poultry houses, constituted 66% of the technology coefficient. The stocking density increased through improvement of the mechanization coefficient. Most of these farms used longitudinal or tunnel ventilation and a combination of small and large fans. Roof insulation was mostly done using glass wool, and corrugated plastic while installing the heaters outside the poultry house. In these farms, the use of nipple drinkers and plate feeders was more prevalent. Moreover, the results showed that feed conversion and production indices have a significant correlation with mechanization coefficient so that farms with better mechanization coefficients had lower conversion ratio (p=0.04) and higher production indices (p=0.015). In general, the results indicated that ventilation and air inlet systems, as well as wall and roof building technologies have the greatest influence on the mechanization coefficient, while better mechanization coefficients translated into improvements in production efficiency and economic performance of poultry farms.

Avaliação metabólica e hemodinâmica de dois protocolos de sedação prolongada em cães / Metabolic and hemodynamic evaluation of two long term sedation protocols in dogs

Objetivou-se determinar a viabilidade de dois protocolos de sedação para ventilação prolongada em cães e seus efeitos hemodinâmicos e metabólicos. Doze cães, alocados aleatoriamente em dois grupos (n=6), receberam infusão contínua de midazolam (0,5mg/kg/h), fentanil (10µg/kg/h) e propofol (18mg/kg/h) no GMF ou cetamina (0,6mg/kg/h), morfina (0,26mg/kg/h) e propofol (18mg/kg/h) no GCM, durante 24 horas. Os cães foram ventilados mecanicamente com FiO2 de 40%, mantendo-se a normocapnia. A FC diminuiu 32% no GMF e 34% no GCM ao longo do tempo, reduzindo o IC em 24% no GMF e em 29% no GCM. A CaO2, o CvmO2, a DO2 e o VO2 diminuíram no GCM (5%, 16%, 31% e 7%) e no GMF (4%, 19%, 26% e 15%), respectivamente. A TEO2 aumentou 32% no GMF e 36% no GCM, sem diferenças entre grupos, porém a calorimetria indireta demonstrou diminuição do VO2, minimizando a redução da DO2. Não houve diferença entre os tempos para extubação, deambulação e recuperação total, com médias globais (minutos) de 33,8±15,9, 134,8±60,7 e 208±77,5, respectivamente. Conclui-se que ambos os protocolos permitiram a ventilação mecânica, com redução do IC e da DO2, porém sem prejuízos hemodinâmicos e metabólicos, podendo ser utilizados com segurança em cães hígidos.(AU)

We aimed to determine the hemodynamic and metabolic parameters of two sedative protocols for long-term ventilation in dogs. Twelve dogs, were randomly allocated in two groups (n=6) who received constant rate infusion (CRI) of midazolam (0,5mg/kg/h), fentanyl (10µg/kg/h) and propofol (18mg/kg/h) in GMF or ketamine (0,6 mg/kg/h), morphine (0,26mg/kg/h) and propofol (18mg/kg/h) in GCM, during 24 hours. The dogs were mechanically ventilated to normocapnia with FiO2 of 40%. Heart rate decreased 32% in GMF and 34% in GCM during infusion time reducing CI in 24% at GMF and 29% at GCM. CaO2, CmvO2, DO2 and VO2 decreased in GCM (5%, 16%, 31% and 7% respectively) and GMF (4%, 19%, 26% and 15% respectively). Extraction ratio increased 32% in GMF and 36% in GCM without differences between groups; however, decreased VO2, evaluated for indirect calorimetry, suggests minimization of DO2 reduction. No differences between time to extubation, sternal recumbency and total recovery time were observed between groups, with an average of 33,8±15,9, 134,8±60,7 e 208±77,5 minutes respectively. We conclude that both protocols allowed mechanical ventilation with IC and DO2 reduction without metabolic and hemodynamic impairment, and can be safely used in healthy dogs.(AU)

Hemodynamic, ventilatory and gasometric evaluation of an experimental bronchopleural fistula1

PURPOSE: To investigate the hemodynamic and ventilatory changes associated with the creation of an experimental bronchopleural fistula (BPF) treated by mechanical ventilation and thoracic drainage with or without a water seal.7 METHODS: Six large white pigs weighing 25 kg each which, after general anesthesia, underwent endotracheal intubation (6mm), and 7mechanically ventilation. Through a left thoracotomy, a resection of the lingula was performed in order to create a BPF with an output exceeding 50% of the inspired volume. The chest cavity was closed and drained into the water sealed system for initial observation of the high output BPF. RESULTS: Significant reduction in BPF output and PaCO2 was related after insertion of a water-sealed thoracic drain, p< 0.05. CONCLUSION: Insertion of a water-sealed thoracic drain resulted in reduction in bronchopleural fistula output and better CO2 clearance without any drop in cardiac output or significant changes in mean arterial pressure.(AU)

DIFERENTES VALORES DE PRESSÃO POSITIVA AO FINAL DA EXPIRAÇÃO, EM SUÍNOS SUBMETIDOS À VENTILAÇÃO CONTROLADA A VOLUME DURANTE O PNEUMOPERITÔNIO E CEFALODECLIVE

Com o delineamento proposto, objetivou-se avaliar a ventilação controlada a volume com diferentes pressões positivas ao final da expiração (PEEP), em suínos submetidos ao pneumoperitônio e posicionados em cefalodeclive. Foram utilizados 24 suínos da raça Large White, com cerca de 55 a 65 dias de idade, pesando entre 15 e 25 kg, distribuídos em 3 grupos (n = 8), o qual diferenciaram-se pela pressão positiva ao final da expiração: PEEP 0 (ventilação controlada a volume e PEEP 0 cmH2O), PEEP 5 (ventilação controlada a volume e PEEP 5 cmH2O) e PEEP 10 (ventilação controlada a volume e PEEP 10 cmH2O). A manutenção da anestesia foi realizada com infusão contínua de propofol (0,2 mg/kg/min) e midazolan (1 mg/kg/h). A ventilação controlada a volume foi ajustada em 8 mL/kg de volume corrente e frequência respiratória de 25 movimentos por minutos. A PEEP foi estabelecida de acordo com cada grupo experimental. Em seguida, os animais foram posicionados em cefalodeclive de 30° e submetidos ao pneumoperitônio com pressão de 15 mmHg. Submeteram-se os dados à análise de variância e o teste de separação de médias (Tukey) foi realizado ao nível de 5% de significância utilizando o programa SAS. O grupo PEEP 10 apresentou maiores valores de Ppico, Cdyn, SO2, IO, PVC e PCPm, enquanto no grupo PEEP 5, [P(a-ET)CO2], IR, PAPm e RVP foram maiores. Já o grupo PEEP 0, apresentou médias mais altas da Rdyn, PvCO2 e IC. Com relação aos momentos, houve diferenças na PaO2, PaCO2, pH, PCO2, ETCO2, Ppico, Pmédia, PAO2, Qs/Qt, IO, VO2, FC, PAS, PAD, PAM, DC, IC, RPT e IRPT. Conclui-se que a PEEP de 10 cmH2O promove melhor estabilidade ventilatória e o pneumoperitônio de 15 mmHg associado ao cefalodeclive aumentam os shunts pulmonares e os níveis da PaCO2.

The aim of the present studuy was to evaluate volume-controlled ventilation with different positive end-expiratory pressures (PEEP), in pigs submitted to pneumoperitoneum and maintained in head-down tilt. Twenty-four Large White pigs were used, between 55 and 65 days old, weighing between 15 and 25 kg, divided into three distinct groups differentiated by positive end-expiratory pressure: PEEP 0 (volume-controlled ventilation and PEEP 0 cmH2O), PEEP 5 (volume-controlled ventilation and PEEP 5 cmH2O) and PEEP 10 (volume-controlled ventilation and PEEP 10 cmH2O) were included in the study. Anesthesia was maintained with continuous infusion of propofol (0.2 mg/kg/min) and midazolam (1 mg/kg/h). Volume-controlled ventilation was adjusted to 8 mL/kg of tidal volume and a respiratory rate of 25 movements per minute. The animals were positioned on a 30 ° head-down tilt and submitted to pneumoperitoneum of 15 mmHg. Numeric data were submitted to analysis of variance followed by Tukey´s post-hoc test, with p < 0.05. The PEEP 10 group showed higher values of Ppico, Cdyn, SO2, IO, PVC and PCPm, while in the PEEP 5 group, [P (a-ET) CO2], IR, PAPm and RVP were higher. The PEEP 0 group had higher means of Rdyn, PvCO2 and IC. Differences between groups were found in PaO2, PaCO2, pH, PCO2, ETCO2, Ppico, Pmédia, PAO2, Qs/Qt, IO,VO2, FC, PAS, PAD, PAM, DC, IC, RPT e IRPT. It is concluded that the 10 cmH2O PEEP provides better ventilatory stability and the 15 mmHg pneumoperitoneum associated with the cephalodeclive increases pulmonary shunts and PaCO2 levels.

Cardiorespiratory dynamics of sedated pigs submitted to different inspired oxygen fractions under controlled mechanical ventilation

Background: Individuals submitted to situations of deep sedation have a marked decrease in their ventilatory capacity.The provision of adequate ventilation and oxygenation in critically ill patients submitted to sedation in intensive therapyhas been the subject of special care. In such cases, exposure to low inspired oxygen fractions (FIO2) is a factor that caninfl uence alveolar perfusion and respiratory performance. The aim of this study is to evaluate the effects of three inspiredoxygen fractions (80%, 60% or 40%) on the cardiorespiratory dynamics of pigs submitted to mechanical ventilation byintermittent positive pressure in deep sedation with propofol-remifentanil.Material, Methods & Results: Twenty crossbred pigs weighing between 17 and 25 kg and aged between 60 and 90 dayswere used. Each animal was submitted to deep sedation for 2h in randomly assigned FIO2 (80%, 60% or 40%). Scores suchas heart and respiratory rate, blood pressure, respirometry (PaO2, P(A-a)O2, PIP, Vmin), physiological dead space, pulmonaryshunt and blood gas analysis (pH, PaO2, PaCO2, HCO3) were observed, evaluated and compared. Patients were evaluatedafter sedation was induced with propofol (12 mg.kg-1) and remifentanil (1 mcg.kg-1). To maintain the level of sedation weused propofol (an average of 18 mg.kg-1.h-1) and remifentanil (0.5 mcg.kg-1.min-1). Intubation was preceded after the onsetof sedation to mechanical ventilation - volume-cycled, intermittent positive pressure. Patients received a tidal volume of10 mL.kg-1 and an I:E ratio of 1:2, positive end-expiratory pressure of 4 cmH2O with three inspired oxygen fractions. Patients respiratory rate was adjusted so as to maintain end-tidal carbon dioxide pressure between 35 and 45 mmHg. Datawere subjected to analysis of variance for repeated measures followed by a Tukey test. Patients receiving a 40% oxygenconcentration showed an average heart rate higher than the others. Shunt levels...(AU)

Cardiorespiratory dynamics of sedated pigs submitted to different inspired oxygen fractions under controlled mechanical ventilation

Background: Individuals submitted to situations of deep sedation have a marked decrease in their ventilatory capacity.The provision of adequate ventilation and oxygenation in critically ill patients submitted to sedation in intensive therapyhas been the subject of special care. In such cases, exposure to low inspired oxygen fractions (FIO2) is a factor that caninfl uence alveolar perfusion and respiratory performance. The aim of this study is to evaluate the effects of three inspiredoxygen fractions (80%, 60% or 40%) on the cardiorespiratory dynamics of pigs submitted to mechanical ventilation byintermittent positive pressure in deep sedation with propofol-remifentanil.Material, Methods & Results: Twenty crossbred pigs weighing between 17 and 25 kg and aged between 60 and 90 dayswere used. Each animal was submitted to deep sedation for 2h in randomly assigned FIO2 (80%, 60% or 40%). Scores suchas heart and respiratory rate, blood pressure, respirometry (PaO2, P(A-a)O2, PIP, Vmin), physiological dead space, pulmonaryshunt and blood gas analysis (pH, PaO2, PaCO2, HCO3) were observed, evaluated and compared. Patients were evaluatedafter sedation was induced with propofol (12 mg.kg-1) and remifentanil (1 mcg.kg-1). To maintain the level of sedation weused propofol (an average of 18 mg.kg-1.h-1) and remifentanil (0.5 mcg.kg-1.min-1). Intubation was preceded after the onsetof sedation to mechanical ventilation - volume-cycled, intermittent positive pressure. Patients received a tidal volume of10 mL.kg-1 and an I:E ratio of 1:2, positive end-expiratory pressure of 4 cmH2O with three inspired oxygen fractions. Patients’ respiratory rate was adjusted so as to maintain end-tidal carbon dioxide pressure between 35 and 45 mmHg. Datawere subjected to analysis of variance for repeated measures followed by a Tukey test. Patients receiving a 40% oxygenconcentration showed an average heart rate higher than the others. Shunt levels...

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...

Feeding behavior and physiological responses of sheep grazing in the semi-arid / Comportamento ingestivo e respostas fisiológicas de ovinos em pastejo no semiárido

Sheep farming is an important social and economic support for the population living in semi-arid zones. These climatic conditions in these regions - a high radiant heat load, especially - may require adjustments in physiology and behavior of the animal to enable their survival. The increased respiratory rate and rectal temperature, with seeking behavioral patterns reduced grazing time and increased idle time are recurrent in the literature as the main physiological and behavioral responses of sheep grazing in high radiant heat load environments. The presence of shadow, natural or artificial, can encourage and facilitate thermolysis physiological adjustments sheep without harm, predominantly, your metabolism. Thus, the objective of compiling information on the main patterns of behavior, as well as major physiological responses of sheep grazing in semi-arid zones.(AU)

A criação de ovinos representa importante suporte social e econômico para as populações instaladas em zonas semiáridas do globo. A condição climática presente nessas regiões elevada carga térmica radiante, principalmente pode exigir ajustes profundos na fisiologia e no comportamento do animal a fim de possibilitar sua sobrevivência. O aumento da frequência respiratória e da temperatura retal, somado a padrões de comportamento buscando redução do tempo de pastejo e elevações do tempo de ócio são recorrentes na literatura como principais respostas fisiológicas e comportamentais dos ovinos pastejando em ambientes de elevada carga térmica radiante. A presença de sombra, seja natural ou artificial, pode favorecer a termólise e facilitar os ajustes fisiológicos dos ovinos, sem prejudicar, preponderantemente, o seu metabolismo. Dessa forma, objetivou-se compilar informações sobre os principais padrões de comportamento, bem como as principais respostas fisiológicas, de ovinos pastejando em zonas semiáridas.(AU)

Feeding behavior and physiological responses of sheep grazing in the semi-arid / Comportamento ingestivo e respostas fisiológicas de ovinos em pastejo no semiárido

Sheep farming is an important social and economic support for the population living in semi-arid zones. These climatic conditions in these regions - a high radiant heat load, especially - may require adjustments in physiology and behavior of the animal to enable their survival. The increased respiratory rate and rectal temperature, with seeking behavioral patterns reduced grazing time and increased idle time are recurrent in the literature as the main physiological and behavioral responses of sheep grazing in high radiant heat load environments. The presence of shadow, natural or artificial, can encourage and facilitate thermolysis physiological adjustments sheep without harm, predominantly, your metabolism. Thus, the objective of compiling information on the main patterns of behavior, as well as major physiological responses of sheep grazing in semi-arid zones.

A criação de ovinos representa importante suporte social e econômico para as populações instaladas em zonas semiáridas do globo. A condição climática presente nessas regiões – elevada carga térmica radiante, principalmente – pode exigir ajustes profundos na fisiologia e no comportamento do animal a fim de possibilitar sua sobrevivência. O aumento da frequência respiratória e da temperatura retal, somado a padrões de comportamento buscando redução do tempo de pastejo e elevações do tempo de ócio são recorrentes na literatura como principais respostas fisiológicas e comportamentais dos ovinos pastejando em ambientes de elevada carga térmica radiante. A presença de sombra, seja natural ou artificial, pode favorecer a termólise e facilitar os ajustes fisiológicos dos ovinos, sem prejudicar, preponderantemente, o seu metabolismo. Dessa forma, objetivou-se compilar informações sobre os principais padrões de comportamento, bem como as principais respostas fisiológicas, de ovinos pastejando em zonas semiáridas.

Effects of controlled and pressure support mechanical ventilation on rat diaphragm muscle / Efeitos da ventilação mecânica controlada e por pressão de suporte no músculo diafragma de ratos

PURPOSE: The objective of this study was to analyze the effects of Pressure Controlled Ventilation mode (PCV-C) and PSV mode in diaphragm muscle of rats. METHODS: Wistar rats (n=18) were randomly assigned to the control group or to receive 6 hours of PCV and PSV. After this period, animals were euthanized and their diaphragms were excised, frozen in liquid nitrogen and stored in at -80º C for further histomorphometric analysis. RESULTS: Results showed a 15 percent decrease in cross-sectional area of muscle fibers on the PCV-C group when compared to the control group (p<0.001) and by 10 percent when compared to the PSV group (p<0.05). Minor diameter was decreased in PCV-C group by 9 percent when compared with the control group (p<0.001) and by 6 percent when compared to the PSV group (p<0.05). When myonuclear area was analyzed, a 16 percent decrease was observed in the PCV-C group when compared to the PSV group (p<0.05). No significant difference between the groups was observed in myonuclear perimeter (p>0.05). CONCLUSION: Short-term controlled mechanical ventilation seems to lead to muscular atrophy in diaphragm fibers. The PSV mode may attenuate the effects of VIDD.(AU)

OBJETIVO: Avaliar os efeitos do modo ventilatório controlado por pressão controlada (PCV-C) e do modo PSV sobre o músculo diafragma de ratos. MÉTODOS: Ratos (n = 18) da linhagem Wistar foram distribuídos no grupo controle (RE) ou para receber AVM por 6 horas no modo PCV-C e no modo PSV. Após esse período, os animais foram eutanasiados, o diafragma retirado e encaminhado para a análise histológica e morfométrica. RESULTADOS: Os resultados revelaram uma redução da área das fibras musculares de 15 por cento no grupo PCV-C em comparação ao controle (p<0,001) e de 10 por cento quando comparado ao grupo PSV (p<0,05). Já com relação ao diâmetro menor observou-se uma redução de 9 por cento do grupo PCV-C em comparação ao controle (p<0,001) e de 6 por cento em relação ao grupo PSV (p<0,05). Quando avaliada a área dos mionúcleos, notou-se uma redução de 16 por cento desse parâmetro no grupo PCV-C, comparado ao PSV (p<0,05). Não houve diferença significativa no perímetro dos mionúcleos entre os grupos estudados (p>0,05). CONCLUSÃO: O grupo PCV-C apresentou atrofia muscular em um período curto de ventilação mecânica. O modo PSV parece atenuar os efeitos da DDIV.(AU)

SOLUÇÕES IÔNICAS E NÃO IÔNICAS EMPREGADAS NA ATIVAÇÃO ESPERMÁTICA E NA FERTILIZAÇÃO ARTIFICIAL DE OVÓCITOS COM SÊMEN CRIOPRESERVADO DE JUNDIÁ (Rhamdia quelen)

O objetivo deste estudo foi ativar o sêmen criopreservado de jundiá (Rhamdia quelen) com diferentes soluções iônicas e não iônicas e, avaliar os efeitos sobre o movimento espermático e sobre as taxas de fertilização artificial. Amostras de sêmen de 24 reprodutores, submetidos à manipulação hormonal com extrato pituitário de carpa, deram origem a quatro amostras compostas ou pools de sêmen. Amostras provenientes de cada pool de sêmen foram diluídas em solução contendo 5% de frutose, 5% de leite em pó e 10% de metanol, envasadas em palhetes de 0,25mL e submetidas à criopreservação. Após o descongelamento, o sêmen foi ativado água destilada e em soluções à base de bicarbonato de sódio (0,20; 0,40; 0,60; 0,80 e 1,00%), cloreto de sódio (0,14; 0,28; 0,56; 0,70; 1,05%);cloreto de potássio (0,17; 0,35; 0,53; 0,71; 0,89%); cafeína (0,23; 0,46; 0,69; 0,93; 1,16%); frutose (0,72; 1,44; 2,16; 2,88; 3,60%); glicose (0,72; 1,44; 2,16; 2,88; 3,60%); L-carnitina (0,77; 1,55; 2,33; 3,10; 3,88%); Sacarose (1,36; 2,73; 4,10; 5,47; 6,84%). As taxas de motilidade, as velocidades e os tempos de ativação espermática foram avaliados por meio do modelo de superfície de resposta. Posteriormente, as amostras de sêmen de outros 24 machos, originaram outros quatro pools de sêmen. Estas amostras foram ativadas com as duas melhores concentrações de cada solução, exceto a cafeína e, utilizadas na fertilização artificial de ovócitos de Rhamdia quelen, empregando-se 70.000 espermatozoides móveis:ovócito. As taxas de fertilização foram avaliadas pela ANOVA, seguida pelo teste de Tukey. Todas as soluções empregadas na ativação espermática influenciaram o movimento dos espermatozóides. As maiores taxas de motilidade e velocidades espermáticas, além das maiores taxas de fertilização foram alcançadas com o emprego de soluções contendo 3,6% de glicose. Estes resultados possivelmente estão associados ao importante papel que a glicose tem no processo de respiração celular e produção de ATP. Portanto o uso da solução contendo 3,6% de glicose maximiza o movimento espermático e consequentemente as taxas de fertilização artificial dos ovócitos de jundiá (Rhamdia quelen).

The objective of this study was to activate the cryopreserved semen of jundia (Rhamdia quelen) with different ionic and nonionic solutions and to evaluate the effects on sperm movement and artificial fertilization rates. Semen samples from 24 breeding herds submitted to hormonal manipulation with pituitary carp extract gave rise to four composite samples or semen pools. Samples from each semen pool were diluted in a solution containing 5% fructose, 5% milk powder and 10% methanol, filled in 0.25 mL straw and submitted to cryopreservation. After thawing, the semen was activated distilled water and in sodium bicarbonate solutions (0.20, 0.40, 0.60, 0.80 and 1.00%), sodium chloride (0.14; 0.28, 0.56, 0.70, 1.05%), potassium chloride (0.17, 0.35, 0.53, 0.71, 0.89%); Caffeine (0.23, 0.46, 0.69, 0.93, 1.16%); Fructose (0.72, 1.44, 2.16, 2.88, 3.60%); Glucose (0.72, 1.44, 2.16, 2.88, 3.60%); L-carnitine (0.77, 1.55, 2.33, 3.10, 3.88%); Sucrose (1.36, 2.73, 4.10, 5.47, 6.84%). Motility rates, velocities and sperm activation times were assessed using the response surface model. Subsequently, semen samples from 24 other males gave rise to four other semen pools. These samples were activated with the two best concentrations of each solution, except caffeine and, used in the artificial fertilization of oocytes of Rhamdia quelen, using 70,000 mobile spermatozoa: oocyte. Fertilization rates were evaluated by ANOVA, followed by the Tukey test. All solutions employed in sperm activation influenced the movement of spermatozoa. The highest rates of motility and sperm velocity, in addition to higher fertilization rates, were achieved with solutions containing 3.6% glucose. These results are possibly associated with the important role that glucose has in the process of cellular respiration and ATP production. Therefore, the use of the solution containing 3.6% glucose maximizes the sperm movement and, consequently, the artificial fertilization rates of jundia ova (Rhamdia quelen).

Determinação da variação da pressão de pulso em equinos anestesiados com isofluorano e mecanicamente ventilados submetidos à reposição volêmica

Objetivo: Determinar a relação entre a PP e a responsividade à expansão volêmica em equinos anestesiados com isoflurano e mecanicamente ventilados. Método: Em estudo prospectivo, oito cavalos Árabes saudáveis (366,5 ± 22,7kg) foram anestesiados. Todos os animais foram aleatoriamente alocados em dois grupos: (I) restrição hídrica de 14h; (II) restrição hídrica de 14h mais pneumoperitôneo de 12mmHg. Anestesia foi induzida com detomidina, diazepam e cetamina e mantida com isoflurano a 1,6% (I) e 1,3 % (II) em todos os animais mecanicamente ventilados (VTexp 14mL/kg) e posicionados em decúbito dorsal. I - Após 30 minutos da indução anestésica foi coletado os parâmetros basais (TBasal) e os animais submetidos a desafio volêmico (DV) com Ringer com Lactato de sódio (15 mL/kg, 15 min) (T1). Animais responsivos (DC > 15%) receberam até dois DV adicionais (T2 e T3, respectivamente). Caso considerado não responsivo, foi administrada dobutamina titulada para PAM 65-75 mmHg por 15 minutos (T4) e após foi realizado novo DV (T5). II Ídem acima, porém após TBasal foi instituído pneumoperitônio (12mmHg) por 15 minutos (PNP) e os desafios realizados com pneumoperitônio. Após (T5), foi descontinuada a hiperdistenção abdominal e coletado os valores (T6). Resultados: FaseI: Não houve aumento significativo no IC em T1 e T4. Porém, houve aumento de 16,5% após novo DV (T5). Não houve aumento significativo na PAM em T1. Porém houve aumento em T4, sem aumento adicional após novo DV (T5). Os valores de PP e PS reduziram em T4, T5 e em T1, T4 e T5, respectivamente, em relação ao valor basal. Porém não houve diferença estatística quando comparados animais responsivos dos não responsivos. Houve aumento de 293% da PVC em T1, mantendo se acima do valor basal por todos os demais momentos. A AUC obtida através da curva ROC foi de 0,83, 0,83 e 0,40 para PP, PAM e PVC, respectivamente para T1 e T2; e 0,55, 0,69 e 0,65 incluíndo T5. FaseII: Não houve alteração significativa no IC e PP em todos os tempos observados. Houve aumento significativo na PAM em relação a Tbasal após DV sob pneumoperitônio (T1). Aumento adicional foi observado após novo desafio volêmico (T5). Os valores de PS reduziram somente após descontinuado pneumoperitônio (T6). Porém não houve diferença estatística quando comparados animais responsivos dos não responsivos. Houve aumento de 363% da PVC após pneumoperitônio (PNP), com aumento adicional de 189% após DV em T1, mantendo se acima do valor basal por todos os demais momentos. Novo aumento foi observado em T5, retornando para valores similares a PNP em T6. A AUC obtida através da curva ROC foi de 0,64, 0,50 e 0,29 para PP, PAM e PVC, respectivamente para T1 e T2; e 0,71, 0,64 e 0,61 incluíndo T5. Conclusão: Utilizando a metodologia empregada, o PP não mostrou ser índice preditivo de responsividade volêmica em equinos anestesiados com isoflurano e mecanicamente ventilados, ocorrendo piora quando empregado pneumoperitônio de 12 mmHg. O emprego da dobutamina também reduziu a sensibilidade/especificidade deste índice. Portanto, acredita-se que o uso desta ferramenta seja limitado na espécie equina.

Objective: To determine the relationship between PP and fluid responsiveness in mechanically ventilated isoflurane anesthetizes horses. Method: In a prospective study, 8 adult healthy Arabian horses (366.5 ± 22.7kg) were anesthetized. All animals were randomly submitted in two groups: (I) 14h of water restriction; (II) 14 h of water restriction associated with 12mmHg of pneumoperitoneum. Anesthesia was induced with detomidine, diazepam and ketamine and maintained with 1.6% (I) or 1.3% (II) end-tidal concentration of isoflurane and all animals were placed dorsal recubency and mechanically ventilated (VTexp 14mL / kg). I - Baseline parameters was collected (TBasal) after 30 minutes of anesthetic induction and animals subjected to blood fluid challenge (VE) with lactate Ringer solution (15 mL / kg, 15 min) (T1). Responsive animals (DC> 15%) received up to two additional VE (T2 and T3, respectively). Dobutamine was given titrated to achieve PAM 65-75 mmHg for 15 minutes (T4) if animals were considered unresponsive. After was submitted to a new VE (T5). II - As described above, with difference after TBasal was established pneumoperitoneum (12 mmHg) for 15 minutes (PNP) and the challenges were realized in animals with pneumoperitoneum. After (T5) abdominal distension was discontinued and collected all values (T6). Results: Phase I: There was no significant increase in CI at T1 and T4. However an increase of 16.5% after new VE (T5). There was no significant increase in MAP at T1. But there was an increase at T4 with no further increase after new VE (T5). PP and PS values decreased compared to TBasal at T4, T5 and T1, T4 and T5, respectively. But there was no statistical difference when compared responsive with unresponsive animals. There was an 293% increase of PVC at T1, keeping above the baseline for all other times. The AUC obtained from ROC curve was 0.83, 0.83 and 0.40 for PP, PVC and CVP respectively for T1 and T2; and 0.55, 0.69 and 0.65 including T5. Phase II: No significant change in CI and PP in all observed times. Significant increase in MAP compared with Tbasal after DV under pneumoperitoneum (T1) was observed. With additional increase after new VE (T5). PS values reduced only after discontinued pneumoperitoneum (T6). However there was no statistical difference when compared responsive with unresponsive animals. There was an 363% increase of PVC after pneumoperitoneum (PNP), with an additional increase of 189% after DV at T1, keeping above the baseline for all other times. Further increase was observed in T5, returning to values similar to PNP at T6. The AUC obtained from the ROC curve was 0.64, 0.50 and 0.29 for PP, PVC and PS respectively for T1 and T2; and 0.71, 0.64 and 0.61 including T5. Conclusion: With the methodology employed, the PP not shown to be a predictor of responsiveness volume in horses anesthetized with isoflurane and mechanically ventilated, occurring worsening when used pneumoperitoneum 12 mmHg. The use of dobutamine also reduced the sensitivity / specificity of this index. Therefore the use of this this tool appears limited in horses.

Anestesia e obesidade canina - revisão de literatura / Anesthesia and canine obesity - review / Anestesia y obesidad canina - revisión de la literatura

A obesidade canina é uma enfermidade que acomete cerca de 40% da população canina mundial, de modo que a chance de um paciente obeso ser submetido a um procedimento cirúrgico e consequentemente ser anestesiado é muito grande. Assim como nos seres humanos, nos cães, o excesso de gordura pode afetar a maioria dos órgãos vitais, e por isso o anestesista tem que estar preparado para se deparar com uma série de desafios, tais como alterações nos sistemas cardiovascular, respiratório e metabólico. Essas alterações podem influenciar a farmacocinética e a farmacodinâmica dos anestésicos e, consequentemente, dificultar a indução e a manutenção do plano anestésico. Em seres humanos, os agentes anestésicos são administrados de acordo com o peso de massa magra, com o intuito de evitar sobre ou subdosagens. Quando se trata de cães, existem poucas informações sobre o assunto, mas recomenda-se o uso de fármacos de curta duração, e a utilização da ventilação mecânica é considerada indispensável.

Canine obesity is a disorder that affects 30% of the canine world population, which increases the chances of an obese patient needing to undergo general anesthesia. As in obese humans, weight excess affects most vital organs of the obese dog and that poses significant challenges to anesthesiologists. Changes in cardiovascular, respiratory and metabolic systems may occur. The obese patient has metabolic disorders that may alter the pharmacokinetics and the pharmacodynamics of the anesthetics, which can in turn lead to difficulties in inducing and maintaining the anesthesia. In human medicine, anesthetic drugs are administered according to lean body weight to avoid over- or under- dosing. Although little information is available as regards canine anesthesia, one recommends the use of short-acting drugs. Furthermore, the use of mechanical ventilation in these patients is indispensable.

La obesidad canina es una enfermedad que afecta a cerca del 40% de la población canina mundial, de manera que siempre existe la posibilidad de que un paciente obeso sea sometido a un procedimiento quirúrgico y, consecuentemente, deba ser anestesiado. Así como en seres humanos, el exceso de grasa en los perros puede afectar a la mayor parte de los órganos vitales; es por eso que el anestesista debe estar preparado para enfrentar una serie de desafíos, como alteraciones de los sistemas cardiovascular, respiratorio y metabólico. Esas alteraciones pueden influir en la farmacocinética y la farmacodinámica de los anestésicos, dificultando la inducción y mantenimiento del plano anestésico. En seres humanos, los agentes anestésicos se administran de acuerdo con el peso de la masa magra, con el objetivo de evitar sobre o sub dosificaciones. En el caso de los perros, existe poca información sobre este asunto, pero se recomienda el uso de fármacos de corta duración, y el uso de ventilación mecánica es considerado indispensable.

Anestesia e obesidade canina - revisão de literatura / Anesthesia and canine obesity - review / Anestesia y obesidad canina - revisión de la literatura

A obesidade canina é uma enfermidade que acomete cerca de 40% da população canina mundial, de modo que a chance de um paciente obeso ser submetido a um procedimento cirúrgico e consequentemente ser anestesiado é muito grande. Assim como nos seres humanos, nos cães, o excesso de gordura pode afetar a maioria dos órgãos vitais, e por isso o anestesista tem que estar preparado para se deparar com uma série de desafios, tais como alterações nos sistemas cardiovascular, respiratório e metabólico. Essas alterações podem influenciar a farmacocinética e a farmacodinâmica dos anestésicos e, consequentemente, dificultar a indução e a manutenção do plano anestésico. Em seres humanos, os agentes anestésicos são administrados de acordo com o peso de massa magra, com o intuito de evitar sobre ou subdosagens. Quando se trata de cães, existem poucas informações sobre o assunto, mas recomenda-se o uso de fármacos de curta duração, e a utilização da ventilação mecânica é considerada indispensável.(AU)

Canine obesity is a disorder that affects 30% of the canine world population, which increases the chances of an obese patient needing to undergo general anesthesia. As in obese humans, weight excess affects most vital organs of the obese dog and that poses significant challenges to anesthesiologists. Changes in cardiovascular, respiratory and metabolic systems may occur. The obese patient has metabolic disorders that may alter the pharmacokinetics and the pharmacodynamics of the anesthetics, which can in turn lead to difficulties in inducing and maintaining the anesthesia. In human medicine, anesthetic drugs are administered according to lean body weight to avoid over- or under- dosing. Although little information is available as regards canine anesthesia, one recommends the use of short-acting drugs. Furthermore, the use of mechanical ventilation in these patients is indispensable.(AU)

La obesidad canina es una enfermedad que afecta a cerca del 40% de la población canina mundial, de manera que siempre existe la posibilidad de que un paciente obeso sea sometido a un procedimiento quirúrgico y, consecuentemente, deba ser anestesiado. Así como en seres humanos, el exceso de grasa en los perros puede afectar a la mayor parte de los órganos vitales; es por eso que el anestesista debe estar preparado para enfrentar una serie de desafíos, como alteraciones de los sistemas cardiovascular, respiratorio y metabólico. Esas alteraciones pueden influir en la farmacocinética y la farmacodinámica de los anestésicos, dificultando la inducción y mantenimiento del plano anestésico. En seres humanos, los agentes anestésicos se administran de acuerdo con el peso de la masa magra, con el objetivo de evitar sobre o sub dosificaciones. En el caso de los perros, existe poca información sobre este asunto, pero se recomienda el uso de fármacos de corta duración, y el uso de ventilación mecánica es considerado indispensable.(AU)