EFFECTS OF DETOMIDINE AND DEXMEDETOMIDINE ON PHYSIOLOGICAL PARAMETERS AND ANESTHETIC RECOVERY IN TAPIRUS TERRESTRIS ANESTHETIZED WITH KETAMINE, GLYCERYL GUAIACOL ETHER, AND MIDAZOLAM.

The aim of this study was to compare the effects of two anesthetic induction protocols for long procedures carried out in the field in Tapiridae. Sixteen tapirs were divided into two groups (n=8) receiving either detomidine (DET) or dexmedetomidine (DEX) for anesthetic induction. All animals were anesthetized by intramuscular administration of a combination of ketamine (1.5 mg/kg), midazolam (0.2 mg/kg), plus either DET (0.04 mg/kg) or DEX (0.007 mg/kg). Anesthetic maintenance was by continuous infusion of ketamine, midazolam, and glyceryl guaiacol ether at 2 mg/kg per hour, 0.1 mg/kg per hour, and 100 mg/kg per hour, respectively). The animals were kept anesthetized for a total of 50 min to allow physical examination and collection of biological material as part of a research program, and physiological variables (heart rate [HR], respiratory rate, oxyhemoglobin saturation [SpO2], rectal temperature [RT], mean arterial pressure [MAP], blood glucose [GLI], and cortisol) and electrocardiogram were recorded during anesthesia. Anesthetic recovery was monitored by two researchers who were not informed of the induction protocol group. The recorded results were statistically evaluated. In both groups there was an initial increase in MAP, which subsequently decreased; RT gradually decreased during anesthesia; HR and GLI increased throughout the procedure; SpO2 was below normal throughout the procedure. Cortisol levels were significantly higher in the DEX group than in the DET group. Also, the animals in the DEX group had a longer recovery time than those in the DET group. On the basis of the results, we conclude that the combination of alpha-2 agonists and midazolam, ketamine, and glyceryl guaicol ether is an appropriate protocol for the anesthesia of tapirs in the field. However, in moderately extended procedures oxygen supplementation is recommended. Additionally, DEX resulted in fewer cardiovascular effects and longer-lasting sedation than DET.

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)

Risk factors for inspiratory muscle weakness in chronic heart failure

BACKGROUND: Chronic heart failure is commonly associated with inspiratory muscle weakness. However, few studies have investigated the risk factors for inspiratory muscle weakness in individuals with chronic heart failure and systolic dysfunction (left-ventricular ejection fraction [LVEF] <40%). METHODS: Seventy subjects were recruited in a cardiac center. We assessed clinical parameters, smoking history, peripheral muscle strength, pulmonary function, echocardiographic variables, and brain natriuretic peptide. The subjects were classified with inspiratory muscle weakness when the maximum inspiratory pressure was <70% of predicted values. RESULTS: Thirty-six subjects (51%) had inspiratory muscle weakness. The subjects with inspiratory muscle weakness and the subjects with no inspiratory muscle weakness were similar in age, sex, body mass index, medication use, and physical activity. However, the subjects with inspiratory muscle weakness had lower LVEF (P = .003), systolic blood pressure (P = .01), diastolic blood pressure (P = .042), quadriceps muscle strength (P = .02), lung function (P = .035), increased brain natriuretic peptide (P = .02), smoking history (P = .01), and pulmonary hypertension incidence (P = .03). Multivariate logistic regression analysis found a lower LVEF, increased smoking history, and lower systolic blood pressure as significant independent predictors for inspiratory muscle weakness. CONCLUSIONS: The combination of lower LVEF, lower systolic blood pressure, and smoking history predicted inspiratory muscle weakness. Patients with suspected inspiratory muscle weakness should be examined and, if inspiratory muscle weakness exists, then inspiratory muscle training should be provided. Reducing inspiratory muscle weakness has the potential to improve many of the deleterious effects of chronic heart failure. (AU)

Risk Factors for Inspiratory Muscle Weakness in Chronic Heart Failure.

BACKGROUND: Chronic heart failure is commonly associated with inspiratory muscle weakness. However, few studies have investigated the risk factors for inspiratory muscle weakness in individuals with chronic heart failure and systolic dysfunction (left-ventricular ejection fraction [LVEF] <40%). METHODS: Seventy subjects were recruited in a cardiac center. We assessed clinical parameters, smoking history, peripheral muscle strength, pulmonary function, echocardiographic variables, and brain natriuretic peptide. The subjects were classified with inspiratory muscle weakness when the maximum inspiratory pressure was <70% of predicted values. RESULTS: Thirty-six subjects (51%) had inspiratory muscle weakness. The subjects with inspiratory muscle weakness and the subjects with no inspiratory muscle weakness were similar in age, sex, body mass index, medication use, and physical activity. However, the subjects with inspiratory muscle weakness had lower LVEF (P = .003), systolic blood pressure (P = .01), diastolic blood pressure (P = .042), quadriceps muscle strength (P = .02), lung function (P = .035), increased brain natriuretic peptide (P = .02), smoking history (P = .01), and pulmonary hypertension incidence (P = .03). Multivariate logistic regression analysis found a lower LVEF, increased smoking history, and lower systolic blood pressure as significant independent predictors for inspiratory muscle weakness. CONCLUSIONS: The combination of lower LVEF, lower systolic blood pressure, and smoking history predicted inspiratory muscle weakness. Patients with suspected inspiratory muscle weakness should be examined and, if inspiratory muscle weakness exists, then inspiratory muscle training should be provided. Reducing inspiratory muscle weakness has the potential to improve many of the deleterious effects of chronic heart failure.

Selected ophthalmic and physiologic parameters in rabbits (Oryctolagus cuniculus) submitted to retrobulbar block with lidocaine, morphine or ketamine / Avaliação de parâmetros oftálmicos e fisiológicos em coelhos (Oryctolagus cuniculus) submetidos a bloqueio retrobulbar com lidocaína, morfina ou cetamina

The aim of the present study was to evaluate selected ophthalmic and physiologic parameters in rabbits submitted to retrobulbar blockade with lidocaine, morphine or ketamine. Eighteen adult rabbits, seven males and eleven females, New Zealand White breed, weighing 3.9 ± 0.7 kg were randomly assigned to perform the retrobulbar block according to the groups: LID (2% lidocaine without a vasoconstrictor - 7 mg kg-1); MOR (1% morphine - 1 mg kg-1) or KET (10% Ketamine - 5 mg kg-1). Ophthalmic and physiologic parameters were assessed, including lacrimal production using Schirmer tear test (STT), corneal touch threshold (CTT), pupillary diameter, intraocular pressure (IOP), pulse rate (PR), respiratory rate (RR), oxyhemoglobin saturation (SpO2), rectal temperature (RT) and systolic, mean and diastolic blood pressures (SAP, MAP and DAP) and were evaluated every 10 minutes for 70 minutes. All drugs used in the present study promoted central positioning of the eyeball for up to one minute later the retrobulbar administration in all cases. There was a significant increase of STT values in MOR and LID, when compared to baseline, while the CTT values had a significant decrease in all groups. KET kept the IOP values unaltered at the time points and there was a significant decrease of pupillary diameter in MOR. There was no significant change in PR, RR and SpO2; however, LID presented significantly lower values of SAP. MOR had increased values for RT when compared to the other two groups. The established parameters may help in ophthalmic procedures using retrobulbar nerve blocks.

Objetivou-se com o presente estudo estabelecer parâmetros oftálmicos e hemodinâmicos em coelhos submetidos ao bloqueio retrobulbar com lidocaína, morfina ou cetamina. Dezoito coelhos da raça Nova Zelândia, adultos, sete machos e onze fêmeas, com peso de 3,9 ± 0,7 kg foram aleatoriamente distribuídos para realização de bloqueio retrobulbar de acordo com os seguintes grupos: LID (lidocaína 2% sem vasoconstrictor ­ 7 mg/kg); MOR (morfina 1% - 1 mg/kg) ou KET (cetamina 10% ­ 5 mg/kg). Os seguintes parâmetros oftálmicos e hemodinâmicos foram avaliados: produção lacrimal através do teste lacrimal de Schirmer (TLS), limiar de sensibilidade corneana ao toque, diâmetro pupilar, pressão intraocular (PIO), frequência de pulso (FP) e respiratória (FR), saturação da oxihemoglobina (SpO2), temperatura retal (TR) e pressão arterial sistólica, diastólica e média (PAS, PAD e PAM). Todos os fármacos utilizados no presente estudo promoveram centralização do bulbo do olho em até um minuto após a sua administração retrobulbar em todos os casos. Houve um aumento significativo do TLS no grupo MOR e LID, quando comparados aos valores basais, enquanto o limiar de sensibilidade corneana reduziu significativamente em todos os grupos. O grupo KET manteve os valores da PIO inalterados em todos os tempos e houve uma redução significativa do diâmetro pupilar no grupo MOR. Não houve alteração significativa dos valores de FP, FR e SpO2. No entanto, o grupo LID apresentou valores significativamente menores de PAS. O grupo MOR apresentou maiores valores de TR quando comparado aos demais grupos. Os parâmetros estabelecidos no presente estudo podem servir como base para a realização de procedimentos oftálmicos que requerem o uso de bloqueio retrobulbar.

Parâmetros ventilométricos e hemogasométricos em cadelas submetidas à ovário-histerectomia, pré-medicadas com tramadol ou morfina e anestesiadas com isofluorano / Ventilometric parameters and arterial blood gases in bitches undergoing ovariohisterectomy, pre-medicated with morphine or tramadol and anesthetized with isoflurane

Avaliaram-se os efeitos nos parâmetros ventilométricos e hemogasométricos em cadelas submetidas à ovário-histerectomia (OHE), pré-medicadas com tramadol ou morfina e anestesiadas com isofluorano. Utilizaram-se 12 cadelas sem raça definida (SRD), divididas em dois grupos (n= 6 para cada grupo), todas com indução anestésica com propofol e manutenção com isofluorano em O2 a 100%, sendo que a diferença entre os grupos se deu pela pré-medicação com tramadol (GT ­ 4mg/kg IM) ou morfina (GM ­ 0,4 mg/kg IM). As observações das variáveis iniciaram-se 30 minutos após a administração do bolus de propofol (M0). As demais colheitas dos dados foram realizadas em intervalos de 15 minutos, por um período de 60 minutos (M15, M30, M45 e M60, respectivamente). Não foram encontradas diferenças significativas entre os grupos ou momentos para as variáveis hemogasométricas, entretanto, as médias de pH, déficit de base (DB) e pressão parcial de dióxido de carbono no sangue arterial (PaCO2 ) ficaram fora da faixa normal para a espécie canina. Foram encontradas diferenças significativas para as variáveis: volume corrente (GM > GT de M0 a M60), pico de fluxo inspiratório e expiratório (GM > GT) e pressão de pico inspiratório, sendo que GM foi maior que GT em M0. Concluiu-se que ambos os opioides são seguros, não causando alterações importantes na ventilometria quando utilizados na pré-medicação em cadelas anestesiadas com isofluorano e submetidas à OHE, porém, a anestesia inalatória com isofluorano deve ser utilizada com cautela em animais com propensão à acidemia.

We evaluated the effects on blood gas and ventilometric parameters in bitches undergoing ovariohysterectomy (OHE), pre-medicated with morphine or tramadol and anesthetized with isoflurane. We used 12 mongrel dogs, distributed into two groups (n = 6 for each group), all with induction of anesthesia with propofol and maintained with isoflurane in 100% O2, and the difference between groups was given by premedication with tramadol (GT - 4mg/kg IM) or morphine (GM - 0.4 mg / kg IM). The measurement of all variables was performed 30 minutes after propofol bolus (M0), and then, in intervals of 15 minutes, during 60 minutes (M15, M30, M45 and M60). No significant differences were found between groups or times for the gas variables, however pH, PaCO2 and DB were outside the normal range for dogs. Significant differences were found for the variables: tidal volume (GM> GT M0 to M60), peak inspiratory and expiratory flow (GM> GT) and peak inspiratory pressure (GM was higher than GT in M0). It was concluded that both opioids are safe and will not cause major changes in ventilometry when used in premedication in dogs anesthetized with isoflurane and submitted to OHE, however, inhalation anesthesia with isoflurane should be used with caution in animals with a tendency to acidemia. .

Parâmetros ventilométricos e hemogasométricos em cadelas submetidas à ovariohisterectomia, pré-medicadas com tramadol ou morfina e anestesiadas com isofluorano / Ventilometric parameters and arterial blood gases in bitches undergoingovariohisterectomy, pre-medicated with morphine or tramadol and anesthetized with isoflurane

Avaliaram-se os efeitos nos parâmetros ventilométricos e hemogasométricos em cadelas submetidas à ovário-histerectomia (OHE),pré-medicadas com tramadol ou morfina e anestesiadas com isofluorano. Utilizaram-se 12 cadelas sem raça definida (SRD), divididasem dois grupos (n= 6 para cada grupo), todas com indução anestésica com propofol e manutenção com isofluorano em O2 a 100%, sendo que a diferença entre os grupos se deu pela pré-medicação com tramadol (GT – 4mg/kg IM) ou morfina (GM – 0,4 mg/kg IM). As observações das variáveis iniciaram-se 30 minutos após a administração do bolus de propofol (M0). As demais colheitas dos dados foram realizadas em intervalos de 15 minutos, por um período de 60 minutos (M15, M30, M45 e M60, respectivamente). Não foram encontradas diferenças significativas entre os grupos ou momentos para as variáveis hemogasométricas, entretanto, as médias de pH, déficit de base (DB) e pressão parcial de dióxido de carbono no sangue arterial (PaCO2) ficaram fora da faixa normal para a espécie canina. Foram encontradas diferenças significativas para as variáveis: volume corrente (GM > GT de M0 a M60), pico de fluxo inspiratório e expiratório (GM > GT) e pressão de pico inspiratório, sendo que GM foi maior que GT em M0.Concluiu-se que ambos os opioides são seguros, não causando alterações importantes na ventilometria quando utilizados na pré-medicação em cadelas anestesiadas com isofluorano e submetidas à OHE, porém, a anestesia inalatória com isofluorano deve ser utilizada com cautela em animais com propensão à acidemia.

We evaluated the effects on blood gas and ventilometric parameters in bitches undergoing ovariohysterectomy (OHE), pre-medicatedwith morphine or tramadol and anesthetized with isoflurane. We used 12 mongrel dogs, distributed into two groups (n = 6 foreach group), all with induction of anesthesia with propofol and maintained with isoflurane in 100% O2, and the difference betweengroups was given by premedication with tramadol (GT - 4mg/kg IM) or morphine (GM - 0.4 mg / kg IM). The measurement of allvariables was performed 30 minutes after propofol bolus (M0), and then, in intervals of 15 minutes, during 60 minutes (M15, M30,M45 and M60). No significant differences were found between groups or times for the gas variables, however pH, PaCO2 and DBwere outside the normal range for dogs. Significant differences were found for the variables: tidal volume (GM> GT M0 to M60),peak inspiratory and expiratory flow (GM> GT) and peak inspiratory pressure (GM was higher than GT in M0). It was concludedthat both opioids are safe and will not cause major changes in ventilometry when used in premedication in dogs anesthetized withisoflurane and submitted to OHE, however, inhalation anesthesia with isoflurane should be used with caution in animals with atendency to acidemia.

Magnesium status and the physical performance of volleyball players: effects of magnesium supplementation.

The aim of this study was to test the hypothesis that magnesium supplementation influences the physical performance of volleyball players, as the efficacy of this approach remains questionable. Twenty-five professional male volleyball players were assigned randomly to experimental (350 mg Mg · d(-1), 4 weeks) and control groups (500 mg maltodextrin · d(-1), 4 weeks) maintaining inter-group homogeneity of urinary magnesium. Erythrocyte, plasma and urinary magnesium levels, plasma creatine kinase activity, lactate production, maximal oxygen uptake (VO2 max) and plyometric (squat jump, countermovement jump, countermovement jump with arm swing) and isokinetic (peak torque, potency and total work) performances were evaluated before (T0) and after (T1) supplementation. Levels of erythrocyte and urinary magnesium and creatine kinase activity and VO2 max remained within normal ranges in both groups. Plasma magnesium decreased significantly only within the experimental group. Significant decreases in lactate production and significant increases (of up to 3 cm) in countermovement jump and countermovement jump with arm swing values were detected in the experimental group following magnesium supplementation, but not in the control group at T1. It is concluded that magnesium supplementation improved alactic anaerobic metabolism, even though the players were not magnesium-deficient.

The effects of different inspired oxygen fractions on gas exchange and Tei-index of myocardial performance in propofol-anesthetized dogs.

OBJECTIVE: To evaluate the influence of different inspired oxygen fractions (FiO2) on pulmonary oxygen exchange and Tei-index of myocardial performance in propofol-anesthetized dogs. STUDY DESIGN: Prospective crossover, randomized, experimental trial. ANIMALS: Eight adult dogs weighing 8.6 ± 1.8 kg. METHODS: The animals were anesthetized on five occasions, receiving either an FiO2 = 1.0 (F100), 0.8 (F80), 0.6 (F60), 0.4 (F40) or 0.21 (F21). Propofol was used for induction (6.45 ± 0.69 mgkg(-1) IV) followed by a continuous rate infusion (CRI, 0.7 mgkg(-1) minute(-1)). The dogs breathed spontaneously. The initial measurements of arterial partial pressures of oxygen (PaO2) and carbon dioxide (PaCO2), arterial hemoglobin saturation (SaO2), heart rate (HR), mean arterial pressure (MAP), cardiac index (CI), stroke index (SI), pre-ejection period (PEP) and left ventricular ejection time (LVET) were performed 30 minutes after beginning the CRI (T0) and then, at 15-minute intervals (T15-T60). From these measurements the following were calculated; alveolar oxygen partial pressure (PAO2), alveolar-arterial oxygen gradient (AaDO2), arterial oxygen partial pressure/inspired oxygen fraction ratio (PaO2/FiO2), arterial-to-alveolar oxygen tension ratio (PaO2/PAO2), respiratory index (RI), oxygen delivery (D·O2), PEP/LVET ratio, isovolumic relaxation time (IVRT) and Tei-index. RESULTS: At T30, PaCO2 in F100 was higher than in F21. The AaDO2 mean in F100 was greater than in other treatments. PaO2/FiO2 in F21 was lower than F100 and F80 at T0 and than in F80 and F60 at T15. At T15, PaO2/PAO2 and RI in F100 were higher than in F80, F60 and F21. At T30, PaO2/PAO2 in F21 was lower than in F100 and F60. At T30, PEP/LVET in F100 was higher than F80, F40 and F21, which was lower than F80 and F40. CONCLUSION: The Tei-index and cardiovascular parameters are not affected by different FiO2. CLINICAL RELEVANCE: An FiO2 of 1.0 and 0.21 impaired respiratory efficiency.

Efectos de la hipotermia moderada en los niveles de glucemia de caninos / Efeitos da hipotermia moderada nas concentrações de glicemia de caninos

Con el objetivo de evaluar las variaciones de la glucemia en caninos sometidos a hipotermia moderada se utilizaron ocho canes adultos, anestesiados con etomidato e isofluorano y sometidos a tres franjas de temperatura: 32-33°C, 34-35°C y normotermia 38,5± 1°C, durante 150 min. La glucosa sérica de estos animales fue evaluada en el periodo basal y cada 30 min durante el periodo experimental. La glucemia fue mayor durante los 60, 90 y 120 min, comparada con las concentraciones basales; fue similar en las franjas de temperatura estudiadas y se mantuvo siempre dentro de los rangos para la especie. La aplicación de hipotermia moderada no altera las concentraciones de glucosa, lo que se constituye en un aspecto relevante en la neuroprotección.

Effects of Moderate Hypothermia in Canine Blood Glucose Concentrations.

With the purpose of evaluating variations in the blood glucose of dogs subjected to moderate hypothermia, eight adult dogs were used, anesthetized with etomidate and isoflurane and subjected to three temperature ranges: 32-33°C, 34-35°C and 38.5 ± 1°C normothermia for 150 minutes. The serum glucose of these animals was assessed at baseline and every 30 min during the experimental period. Blood glucose was higher during 60, 90 and 120 min, compared with basal concentrations; it was similar in the temperature ranges studied and was always within the range for the species. The application of moderate hypothermia does not alter glucose concentrations, which constitutes an important aspect in neuroprotection.

Com o objetivo de avaliar as variações da glicemia em caninos submetidos à hipotermia moderada, se utilizaram oito cães adultos, anestesiados com etomidato e isoflurano e submetidos a três franjas de temperatura: 32-33°C, 34-35°C e normotermia 38,5± 1°C, durante 150 min. A glucose sérica destes animais foi avaliada no período basal e a cada 30 minutos durante o período experimental. A glicemia foi maior durante os 60, 90 e 120 minutos comparada com as concentrações basais; foi similar nas faixas de temperatura estudadas e se manteve sempre dentro dos níveis para a espécie. A aplicação de hipotermia moderada não altera as concentrações de glucose, o que se constitui em um aspecto relevante na neuroproteção.

Efectos cardiorespiratorios y requerimientos de isofluorano en conejos sometidos a cirugía oftalmológica tratados con tramadol pre, intra y postoperatorio / Cardiorespiratory effects and isoflurane requirements in rabbits subjected to ophthalmologic surgery treated with tramadol pre-, intra- or postoperatively

Para evaluar los efectos cardiorespiratorios y los requerimientos de isofluorano en conejos sometidos a cirugía oftálmica tratados en diferentes momentos con tramadol, fue realizado un estudio prospectivo experimental de tipo ciego en 24 conejos distribuidos aleatoriamente en tres grupos de ocho individuos cada uno: grupo tramadol preoperatorio (Tpre), grupo tramadol transoperatorio (Ttrans) y grupo tramadol postoperatorio (Tpos). Cada animal recibió tres inyecciones intramusculares de igual volumen en los periodos pre, intra y postoperatorio, conteniendo tramadol (4mg/kg) o NaCl 0,9%, de acuerdo al momento indicado para cada grupo. La inducción y mantenimiento anestésico fueron realizados con isofluorano en FiO2 1,0. Una vez estabilizado el plano anestésico, fue iniciado el procedimiento quirúrgico. Se evaluaron: frecuencia cardíaca (FC), presión arterial media (PAM), frecuencia respiratoria (f), presión de CO2 al final de la expiración (EtCO2), saturación parcial de oxihemoglobina (SpO2) y concentración de isofluorano al final de la expiración (EtISO). Las variables fueron medidas después de la estabilización anestésica (m1) y cada 10 min desde el inicio de la cirugía, hasta el final del experimento (m10 a m40). La FC, SpO2, f , EtCO2 y EtISO fueron similares entre grupos durante todo el tiempo. La PAM fue significativamente mayor (p<0,01) durante m1 comparada con el resto del tiempo y el grupo Tpre mostró valores inferiores (p=0,04) de este parámetro durante m1 con relación a los demás grupos. El clorhidrato de tramadol promueve la reducción transitoria de la presión arterial en conejos anestesiados con isofluorano y sometidos a cirugía oftálmica. La administración preoperatoria del fármaco no disminuye el requerimiento anestésico y resulta en hipotensión más pronunciada. Adicionalmente, la anestesia con isofluorano, asociada al reflejo óculo-cardiaco, generan hipotensión arterial, fenómeno que debe tenerse en cuenta durante cirugías oftalmológicas.

To evaluate the cardiorespiratory effects and isoflurane requirements of tramadol applied at different times during ophthalmic surgery, a blind prospective study was made in 24 rabbits, randomly divided into three groups of eight subjects each: pre-operatory tramadol group (Tpre), trans-operatory tramadol group (Ttrans) and post-operatory tramadol group (Tpos), which received three intramuscular injections of equal volume, in the pre, intra and post-operative period, containing tramadol hydrochloride (4 mg/kg) or NaCl 0,9%, according to each group. Anesthetic induction and maintenance was made with isoflurane diluted FiO2 1.0. Once the anesthetic plane was stabilized, surgical procedure was started. Were evaluated heart rate (HR), medium arterial presseure (MAP), respiratory rate (f), end tidal CO2 (EtCO2), Oxihemoglobin saturation (SpO2) and end tidal isoflurane (EtISO). Variables were measured after anesthesia stabilization (m1) and every 10 min after onset of surgery, until the end of experimental protocol (m10 to m40). HR, SpO2, f, EtCO2 and EtISO were similar among groups at all times. MAP were significantly higher (p<0.01) in m1 than in other moments and Tpre group showed lower (p=0.04) values than the other groups at this moment. Tramadol hydrochloride promotes transient reduction of blood pressure in isoflurane anesthetized rabbits subjected to ophthalmic surgery. The preoperative administration of the drug does not reduce the anesthetic requirement and results in a more pronounced hypotension. Additionally, isoflurane anesthesia, associated to oculocardiac reflex generates a hypotension phenomenon that must be taken in to considertation during ophthalmologic surgeries.

Diferentes frações inspiradas de oxigênio em coelhos hipovolêmicos anestesiados com propofol e submetidos à ventilação mecânica / Different fractions of inspired oxygen in hypovolemic rabbits anesthetized with propofol and maintained in mechanic ventilation

Avaliaram-se os efeitos do fornecimento de diferentes frações inspiradas de oxigênio (FiO²) em coelhos hipovolêmicos, anestesiados com infusão contínua de propofol e mantidos em ventilação controlada sobre os parâmetros respiratórios, hemogasométricos e hemodinâmicos. Foram utilizados 50 coelhos (Nova Zelândia), pesando 3,5±0,3kg, distribuídos em 5 grupos: G100 (FiO²=1), G80 (FiO²=0,8), G60 (FiO²=0,6), G40 (FiO²=0,4) e G21 (FiO²=0,21), os quais receberam xilazina (1mg kg-1) e cetamina (15mg kg-1) pela via intramuscular. Transcorridos 20 minutos, foi administrado propofol (8mg kg-1 bolus e 0,5mg kg-1 min-1) e rocurônio (0,6mg kg-1 bolus e 0,6mg kg-1 h-1). Iniciou-se então, a ventilação mecânica no modo pressão controlada. Após 30 minutos, os animais foram submetidos à hipovolemia aguda, retirando-se sangue arterial (12mL kg-1). Os parâmetros foram mensurados 30 minutos após a indução anestésica (M0) e a cada dez minutos depois da exsanguinação (M1- M7). As variáveis foram submetidas à análise de variância seguida pelo teste de Tukey (P<0,05). Os valores de PaO², SaO², P A O², AaDO² diminuíram quanto mais baixas foram as FiO². Após a indução da hipovolemia, as variáveis DC, PAM, PaO², SaO², Vt, AaDO² diminuíram significativamente. Nenhuma alteração foi notada nos parâmetros FC e PaCO². As FiO² de 0,8 e 1,0 mostraram-se as mais indicadas por manter melhor estabilidade ventilatória e adequada troca gasosa.

The effects of several inspired oxygen fractions (FiO²) on the blood gases, respiratory and hemodynamic parameters in mechanical ventilation hypovolemic rabbits anesthetized with continuous infusion of propofol were evaluated. A total of 50 rabbits (New Zealand), weighing 3.5±0.3kg, were divided into five groups: G100 (FiO²=1), G80 (FiO²=0.8), G60 (FiO²=0.6), G40 (FiO²=0.4) and G21 (FiO²=0.21), which received xylazine (1mg kg-1) and ketamine (15mg kg-1) intramuscularly. Exactly after 20 minutes, it was administered propofol (8mg kg-1 bolus and 0.5mg kg-1 min-1) and rocuronium (0.6mg kg-1 bolus and 0.6mg kg-1 h-1. Then, the mechanical ventilation by controlled pressure mode began. After 30 minutes, the animals underwent acute hypovolemia, withdrawing arterial blood (12mL kg-1). The parameters were measured 30 minutes after anesthetic induction (M0) and every ten minutes after exsanguination (M1-M7). The variables were subjected to analysis of variance followed by Tukey test (P<0.05). The values of PaO², SaO², PAO², AaDO² decreased as lower were the FiO². After the induction of hypovolemia, the variables CO, MAP, PaO², SaO², Vt, AaDO² decreased significantly. No change was noted in the parameters HR and PaCO². The FiO² of 0.8 and 1.0 proved to be the most suitable for maintaining stability, better ventilation and adequate gas exchange.

Hemodynamic effects of butorphanol in desflurane-anesthetized dogs.

OBJECTIVE: To evaluate the effects of butorphanol on cardiopulmonary parameters in dogs anesthetized with desflurane and breathing spontaneously. STUDY DESIGN: Prospective, randomized experimental trial. ANIMALS: Twenty dogs weighing 12 ± 3 kg. METHODS: Animals were distributed into two groups: a control group (CG) and butorphanol group (BG). Propofol was used for induction and anesthesia was maintained with desflurane (10%). Forty minutes after induction, the dogs in the CG received sodium chloride 0.9% (0.05 mL kg(-1) IM), and dogs in the BG received butorphanol (0.4 mg kg(-1) IM). The first measurements of body temperature (BT), heart rate (HR), arterial pressures (AP), cardiac output (CO), cardiac index (CI), central venous pressure (CVP), stroke volume index (SVI), pulmonary arterial occlusion pressure (PAOP), mean pulmonary arterial pressure (mPAP), left ventricular stroke work (LVSW), systemic (SVR) and pulmonary (PVR) vascular resistances, respiratory rate (f(R) ), and arterial oxygen (PaO(2) ) and carbon dioxide (PaCO(2) ) partial pressures were taken immediately before the administration of butorphanol or sodium chloride solution (T0) and then at 15-minute intervals (T15-T75). RESULTS: In the BG, HR, AP, mPAP and SVR decreased significantly from T15 to T75 compared to baseline. f(R) was lower at T30 than at T0 in the BG. AP and f(R) were significantly lower than in the CG from T15 to T75. PVR was lower in the BG than in the CG at T30, while PaCO(2) was higher compared with T0 from T30 to T75 in the BG and significantly higher than in the CG at T30 to T75. CONCLUSIONS AND CLINICAL RELEVANCE: At the studied dose, butorphanol caused hypotension and decreased ventilation during desflurane anesthesia in dogs. The hypotension (from 86 ± 10 to 64 ± 10 mmHg) is clinically relevant, despite the maintenance of cardiac index.

Ovário-histerectomia vídeo-assistida com único portal em cadelas: estudo retrospectivo de 20 casos / Single-port video-assisted ovariohysterectomy in bitches: retrospective study of 20 cases

O objetivo do presente estudo foi avaliar retrospectivamente as 20 primeiras ovário-histerectomias vídeo-assistidas com único portal (SPVA-OSH), realizadas por um cirurgião não proficiente nessa técnica. Vinte cadelas foram submetidas à laparoscopia para SPVA-OSH, com o auxílio de um endoscópio de 10mm, com canal de trabalho de 5mm, inserido por um trocarte, posicionado na região pré-púbica, e coagulação bipolar. O tempo cirúrgico médio foi de 22,95±5,17 minutos. Os cinco primeiros procedimentos consumiram mais tempo cirúrgico do que os demais. A abordagem aos pedículos ovarianos direito e esquerdo foram as etapas que apresentaram maior tempo de execução. Houve complicação leve ou moderada em seis (30 por cento) das 20 cadelas operadas. As complicações foram: hemorragia leve ou moderada em um dos pedículos ovarianos em quatro (20 por cento) cadelas e hemorragia grave, devido à punção do baço com agulha de Veress em dois (10 por cento) animais. A SPVA-OSH foi realizada em cadelas por um cirurgião no início da curva de aprendizado, sem complicações maiores.

The aim of the present study was to evaluate retrospectively the first 20 cases of single-port video-assisted ovariohysterectomy (SPVA-OSH) performed by an inexperienced surgeon. Twenty bitches submitted to SPVA-OSH were assessed. A 10mm operative rigid endoscope with one 5 mm working channel and bipolar coagulation was used. The trocar was positioned in the prepubic area of the abdomen. Surgical time and complication rates were assessed descriptively. Mean surgical time was of 22.95±5.17 minutes. Mild or moderate complications were present in six (30 percent) out of 20 bitches that were operated. The first five surgical procedures spent more time to be performed than the others. The longest transoperative momentum time of execution was spent in the approach to the left and right ovarian pedicles. The complications were: mild or moderate hemorrhage from one of the ovarian pedicles in four bitches (20 percent) and severe hemorrhage due to accidental puncture of the spleen with Veress needle in two animals (10 percent). SPVA-OSH was performed in bitches by an inexperienced surgeon, without severe complications.

Técnicas de acesso cirúrgico vascular destinadas à monitoração invasiva em cães / Técnicas de acceso quirúrgico vascular para el monitoreo invasivo en perros / Surgical vascular access techniques for the dog invasive monitoring

A monitoração é essencial durante os procedimentos anestésicos, e pode ser realizada por métodos invasivos ou não-invasivos. A monitoração invasiva é obtida mediante a colocação de instrumentos no interior do corpo do animal, principalmente em vasos sanguíneos. Desse modo, objetivou-se com este estudo apresentar técnicas de abordagem cirúrgica vascular destinadas a monitoração invasiva em cães, descrever os acessos dos principais vasos sanguíneos, como as artérias femoral, safena medial, carótida comum, metatársica e sublingual e das veias jugular externa, femoral e safena medial e revisar os materiais necessários para a canulação destes vasos, bem como, as principais complicações dessas técnicas de abordagem cirúrgica.

Monitoring is essencial during anhestesic procedures, and can be performed by invasive or non-invasive methods. Invasive monitoring is anchieved with the insert of instruments inside the animal body, mainly in blood vessels. Thus, it was aimed with this study to present techniques of vascular surgical approach for invasive monitoring of dogs, describe the access of the main blood vessels, as the femoral artery, medial saphenous artery, carotid artery, metatarsal artery and sublingual artery, and the extern jugular vein, femoral and saphenous veins. Besides, the materials needed for vessel canulation are revised, and also the main complications of these surgical approach techniques.

El monitoreo es esencial durante los procedimientos anestésicos, y puede realizarse por métodos invasivos o no-invasivos. El monitoreo invasivo se logra mediante la colocación de instrumentos en el interior del cuerpo del animal, principalmente en vasos sanguíneos. Así, se buscó con este estudio presentar técnicas de abordaje quirúrgica vascular destinadas al monitoreo invasivo en perros, describir los accesos de los principales vasos sanguíneos, como las arterias femoral, safena medial, carótida común, metatársica y sublingual y de las venas yugular externa, femoral y safena medial, también revisar los materiales necesarios para canulación de estos vasos, así como las principales complicaciones de esas técnicas de abordaje quirúrgica.

Comparison between two methods for cardiac output measurement in propofol-anesthetized dogs: thermodilution and Doppler.

OBJECTIVE: To compare cardiac output (CO) measured by Doppler echocardiography and thermodilution techniques in spontaneously breathing dogs during continuous infusion of propofol. To do so, CO was obtained using the thermodilution method (CO(TD)) and Doppler evaluation of pulmonary flow (CO(DP)) and aortic flow (CO(DA)). STUDY DESIGN: Prospective cohort study. ANIMALS: Eight adult dogs weighing 8.3 +/- 2.0 kg. METHODS: Propofol was used for induction (7.5 +/- 1.9 mg kg(-1) IV) followed by a continuous rate infusion at 0.7 mg kg(-1) minute(-1). The animals were positioned in left lateral recumbency on an echocardiography table that allowed for positioning of the transducer at the 3rd and 5th intercostal spaces of the left hemithorax for Doppler evaluation of pulmonary and aortic valves, respectively. CO(DP) and CO(DA) were calculated from pulmonary and aortic velocity spectra, respectively. A pulmonary artery catheter was inserted via the jugular vein and positioned inside the lumen of the pulmonary artery in order to evaluate CO(TD). The first measurement of CO(TD), CO(DP) and CO(DA) was performed 30 minutes after beginning continuous infusion (T0) and then at 15-minute intervals (T15, T30, T45 and T60). Numeric data were submitted to two-way anova for repeated measurements, Pearson's correlation coefficient and Bland & Altman analysis. Data are presented as mean +/- SD. RESULTS: At T0, CO(TD) was lower than CO(DA). CO(DA) was higher than CO(TD) and CO(DP) at T30, T45 and T60. The difference between the CO(TD) and CO(DP), when all data were included, was -0.04 +/- 0.22 L minute(-1) and Pearson's correlation coefficient (r) was 0.86. The difference between the CO(TD) and CO(DA) was -0.87 +/- 0.54 L minute(-1) and r = 0.69. For CO(TD) and CO(DP), the difference was -0.82 +/- 0.59 L minute(-1) and r = 0.61. CONCLUSION: Doppler evaluation of pulmonary flow was a clinically acceptable method for assessing the CO in propofol-anesthetized dogs.

Atelectasia pulmonar em cães durante anestesia geral / Pulmonary atelectasis in dogs during general anesthesia

A pressão intrapleural normalmente é menor que a pressão intrapulmonar. Consequentemente , os pulmões tendem ao colapso e se retraem, afastando-se da parede torácica. No início do século XX, Pasteur descreveu a atelectasia pulmonar, que ocorre com frequência durante a indução anestésica, persiste no período pós-operatório e pode contribuir de maneira significativa para a morbidade e o aumento nos gastos com medicamentos. Em medicina veterinária, no entanto, a atelectasia não é frequentemente diagnosticada, apesar de que isso não implica afirmar que tal afecção não ocorra, visto que existem relatos do desenvolvimento desse quadro em cães e em outras espécies. No contexto da anestesia geral, essa complicação pulmonar pode ser encontrada em animais que respiram 80 a 100 por cento de oxigênio. A partir dessas informações, torna-se necessário que o profissional da anestesiologia veterinária obtenha conhecimentos complementares sobre o tema. Com este trabalho, objetivou-se descrever alguns dos mecanismos da atelectasia e seus pontos relevantes, de modo a familiarizar os profissionais quanto aos pormenores dessa importante, e nem sempre bem compreendida, alteração fisiológica respiratória.

Pleural pressure is usually lower than pulmonary pressure. Therefore, the lungs tend to collapse and increase its distance from thoracic walls. At the beginning of 20th century, Pasteur described the pulmonary atelectasis, which develops during induction of anesthesia and persists to the postoperative period. It can contribute significantly to morbidity and to increase the medical expenses. In veterinary medicine, pulmonary atelectasis is not frequently diagnosed, which doesn't rule out the occurrence of this disease, since there are reports of atelectsasis in dogs. This pulmonary complication can be found in animals that breathe 80 percent to 100 percent oxygen in anesthetic procedures. Based on this information, the veterinary anesthesiologist is required to search for complementary knowledge regarding to pulmonary atelectasis. This study, therefore, aimed to describe some of the mechanisms involved in the development of atelectasis. It aimed also to familiarize the anesthesiologist to this not always well- understood physiological breathing change.

Alterações em variáveis cardiovasculares e intracranianas induzidas pela associação de buprenorfina e sevoflurano em cães

Objetivou-se, com este experimento, estudar possíveis alterações nas variáveis cardiovasculares e intracranianas promovidas pela buprenorfina, em cães anestesiados. Utilizaram-se oito cães adultos, clinicamente saudáveis. Aanestesia foi induzida com propofol (8 mg/kg IV) e eAi $~g.uida ·os ànimais foram erittJbados ~com sonda orotraqueal de Magill,a qual foi conectada ao aparelho de anestesia volátii4Jara,administração de sevoflurano {1,3 CAM). Os animais foram mantidossob ventilação controlada durante o período experimental. Após 20 minutos do posicionamento do cateter de pressãointracraniana (PIC), foi aplicada buprenorfina {0,02 mg/kg IV}. Avaliou-se: PIC; temperatura intracraniana (TIC); pressão deperfusão cerebral (PPC); freqüência cardíaca (FC); pressões arteriais sistólica, média e diastólica (PAS, PAM e PAD, respectivamente);débito cardíaco (DC); pressão venosa central (PVC); pressão da artéria pulmonar (PAP); e temperatura corporal(TC). As colheitas foram feitas nos seguintes momentos: M1 -" 20 minutos após o posicionamento do cateter de PIC; M2 - 15minutos após a administração do opióide; M3, M4 e M5- de 15 em 15 minutos após M2. A avaliação estatística dos dados foiefetuada por meio do Teste de Tukey (P 0,05). A PIC permaneceu estável durante todo o período experimental, sendoobservada discreta elevação em M2, mas sem significado clínico ou estatístico. Entretant

Some cardiopulmonary effects of sevoflurane in crested caracara (Caracara plancus).

OBJECTIVE: To evaluate the cardiorespiratory changes induced by sevoflurane (SEV) anesthesia in the crested caracara (Caracara plancus). STUDY DESIGN: Prospective experimental trial. ANIMALS: Eight crested caracaras (Caracara plancus) weighing 1.0 (0.9-1.1) kg were used for the study. METHODS: The birds were anesthetized by face mask with isoflurane for brachial artery catheterization. After recovery, anesthesia was re-induced with 6% SEV via face mask. After induction, a noncuffed endotracheal tube was placed and anesthesia was maintained with SEV (3.5% end-tidal) in oxygen (1 L minute(-1)) using an Ayre's T-piece nonrebreathing circuit, with spontaneous ventilation. Electrocardiography (ECG), direct systolic, diastolic and mean arterial blood pressure (SAP, DAP, and MAP), respiratory rate (f(R)), end-tidal carbon dioxide (Pe'CO(2)), and cloacal temperature (T degrees C) were measured before induction (baseline - under physical restraint) and after 5, 10, 15, 20, 25, 30, 35 and 40 minutes of SEV anesthesia. Arterial blood samples were collected for gas analysis at baseline and then at 10, 25 and 40 minutes. RESULTS: No ventricular arrhythmias were observed in the present study. Respiratory rate, SAP, DAP, MAP, T degrees C and pH decreased from pre-induction values, while arterial partial pressures of oxygen and carbon dioxide, bicarbonate concentration, and Pe'CO(2) were significantly higher than baseline. None of the birds were apneic. CONCLUSION AND CLINICAL RELEVANCE: Sevoflurane anesthesia is suitable for use in healthy members of this species, despite the moderate cardiovascular and respiratory depression produced.

The effects of 2 levels of the inspired oxygen fraction on blood gas variables in propofol-anesthetized dogs with high intracranial pressure.

The influence of 2 different levels of the inspired oxygen fraction (FiO2) on blood gas variables was evaluated in dogs with high intracranial pressure (ICP) during propofol anesthesia (induction followed by a continuous rate infusion [CRI] of 0.6 mg/kg/min) and intermittent positive pressure ventilation (IPPV). Eight adult mongrel dogs were anesthetized on 2 occasions, 21 d apart, and received oxygen at an FiO2 of 1.0 (G100) or 0.6 (G60) in a randomized crossover fashion. A fiberoptic catheter was implanted on the surface of the right cerebral cortex for assessment of the ICP. An increase in the ICP was induced by temporary ligation of the jugular vein 50 min after induction of anesthesia and immediately after baseline measurement of the ICP. Blood gas measurements were taken 20 min later and then at 15-min intervals for 1 h. Numerical data were submitted to Morrison's multivariate statistical methods. The ICP, the cerebral perfusion pressure and the mean arterial pressure did not differ significantly between FiO2 levels or measurement times after jugular ligation. The only blood gas values that differed significantly (P < 0.05) were the arterial oxygen partial pressure, which was greater with G100 than with G60 throughout the procedure, and the venous haemoglobin saturation, that was greater with G100 than with G60 at M0. There were no significant differences between FiO2 levels or measurement times in the following blood gas variables: arterial carbon dioxide partial pressure, arterial hemoglobin saturation, base deficit, bicarbonate concentration, pH, venous oxygen partial pressure, venous carbon dioxide partial pressure and the arterial-to-end-tidal carbon dioxide difference.