Bispectral index assessment in calves subjected to the continuous infusion of propofol combined with fentanyl administration / Indice biespectral em bezerros submetidos à infusão contínua de propofol associado ao fentanil

The aim of this study was to evaluate the bispectral index (BIS) effects in calves through continuous infusion of propofol with or without fentanyl. Eight Holstein male calves (ages from six to twelve months old) with an average weight of 123±18kg were used. All animals participated in both groups, always keeping a minimum interval of one week between the anesthetic procedures; the calves were randomly distributed between groups. Anesthesia was induced with an intravenous (IV) dose of propofol of 5mg kg-1 in control group (GP) or with propofol (4mg kg-1) associated with IV fentanyl 0.001mg kg-1(GF). All the calves were positioned in right lateral recumbency and were allowed to spontaneously breathe room air. Subsequently, the anesthesia was maintained by continuous infusion of propofol at the rate of 0.6mg kg-1 min-1 IV in GP, and associated with the infusion of fentanyl 0.001mg kg-1 hour-1 in GF. Measurements of BIS, signal quality index (SQI) and electromyography (EMG) were evaluated before anesthesia induction (TB), and at 15, 30, 45 and 60 minutes after the beginning of continuous drugs infusion (T15, T30, T45 and T60, respectively). The heart rate (HR), respiratory rate (f), end-tidal carbon dioxide tension (ETCO2) and recovery times were evaluated as well. No significant differences were observed between the groups in the BIS variables and the recovery time was longer in GF. Co-administration of propofol and fentanyl infusions, at the doses reported here, did not change the values of BIS in cattle, but delayed the recovery time.(AU)

O estudo teve por objetivo avaliar o índice biespectral (BIS) durante a infusão contínua de propofol associado ou não ao fentanil em bezerros. Foram utilizados oito animais machos entre seis e doze meses de idade, holandeses, com massa corporal média de 123±18kg. Todos os animais participaram de ambos os grupos, respeitando-se sempre um intervalo mínimo de uma semana entre uma anestesia e outra, sendo aleatoriamente distribuídos entre os grupos. A anestesia nos bezerros foi induzida com propofol na dose de 5mg kg-1; intravenoso (IV), grupo controle (GP) ou propofol 4mg kg-1 associado ao fentanil 0,001mg kg-1; IV, grupo fentanil (GF) e posicionados em decúbito lateral direito, onde permaneceram respirando espontaneamente ar ambiente. Ato contínuo, a manutenção anestésica foi realizada pela infusão contínua de propofol na taxa de 0,6mg kg-1 min-1; IV GP, associado ou não à infusão de fentanil 0.001mg kg-1 hora-1 GF. A mensuração das variáveis do BIS, índice de qualidade de sinal (IQS) eletromiografia (EMG), frequência cardíaca (FC), frequência respiratória (f) e dióxido de carbono ao final da expiração (ETCO2)foram avaliadas antes da indução anestésica no momento basal (MB), e 15, 30, 45 e 60 minutos após o início da infusão contínua dos fármacos (M15, M30, M45 e M60, respectivamente); o tempo de recuperação também foi avaliado. Não foram observadas diferenças significativas entre os grupos nas variáveis do BIS e o tempo de recuperação foi maior no GF. A co-administração das infusões de propofol e fentanil, nas doses utilizadas nesse estudo, não alterou os valores do BIS em bezerros, porém, prolongou o tempo de recuperação.(AU)

Bispectral index in calves anesthetized with xylazine, midazolam, ketamine, isoflurane and subjected to continuous rate infusion of lidocaine

PURPOSE: To assess the bispectral index (BIS) and recovery in calves anesthetized with xylazine, midazolam, ketamine and isoflurane and subjected to CRI of lidocaine. METHODS: Xilazine was administered followed by ketamine and midazolam, orotracheal intubation and maintenance on isoflurane using mechanical ventilation. Lidocaine (2 mg kg-1 bolus) or saline (0.9%) was administered IV followed by a CRI (100 µg kg-1 minute-1) of lidocaine (L) or saline (C). Were recorded BIS, heart rate (HR), mean arterial pressure (MAP) and rectal temperature (RT) before administration of premedication (TB) and 15 minutes after (TX), before administering lidocaine (T0) and 20, 40, 60 and 80 minutes after the start of the CRI . Time do sternal recumbency (SRE) and standing (ST) and plasma lidocaine concentration also evaluated. RESULTS: In both treatments BIS decreased significantly at all times compared to TB. TX was higher than the subsequent times. HR decreased from baseline at all times and decreased from T40 in L compared to C. SRE was higher in L compared to C. CONCLUSIONS: Bispectral index values were consistent with the degree of hypnosis of the animals. Lidocaine did not potentiate isoflurane anesthesia assessed by BIS in unstimulated calves anesthetized with constant E´Iso. Lidocaine increased the time to sternal recumbency.(AU)

Alteração do índice biespectral antes e após estimulação elétrica ou mecânica em cães anestesiados pelo isofluorano / Bispectral index changes before and after electrical or mechanical stimulation in isoflurane-anesthetized dogs

Uma das formas atuais para se avaliar o grau de hipnose e depressão do sistema nervoso central durante a anestesia é o índice biespectral (BIS), que fornece um valor de 0 a 100. Objetivou-se avaliar as alterações do BIS de cães durante a estimulação elétrica e mecânica supra-máxima e sob diferentes concentrações de isofluorano, a fim de verificar se existe uma relação entre este índice e a resposta motora frente à nocicepção. Utilizaram-se sete cães da raça Beagle, dois machos e cinco fêmeas, anestesiados com isofluorano nas concentrações de 2,0; 1,8; 1,6; 1,4 e 1,2%. Os diferentes tipos de estímulo foram utilizados em procedimentos anestésicos diferentes nos mesmos animais, com intervalo mínimo de 15 dias. Os valores de BIS foram anotados por 60 segundos em cada avaliação, derivando médias antes (AE) e depois (DE) de cada estímulo. Os resultados foram analisados por meio de teste t pareado ou Wilcoxon pareado (P 0,05). Houve diferença significativa entre os valores AE e DE em todas as concentrações de isofluorano, exceto 2,0% no estímulo mecânico. Também foi significativa entre a subtração desses valores, quando comparados entre estímulos, em 1,8 e 2,0%. Conclui-se que a resposta frente a estímulos supra-máximos modifica os valores de BIS em cães por meio da superficialização do plano anestésico. Sugere-se o emprego do modelo mecânico para evitar possíveis interferências de corrente elétrica e perda da confiabilidade dos dados.(AU)

One of the current methods to assess hypnosis and central depression during anesthesia is the bispectral index (BIS), which generates a number from 0 to 100. The purpose of the present study was to evaluate the changes in BIS during electrical or mechanical supra-maximal stimulation in order to investigate whether there is a relation between this index and motor response to nociception. Seven beagle dogs were included, two males and five females, which were anesthetized with isoflurane at 2.0, 1.8, 1.6, 1.4 and 1.2%. Different types of stimuli were employed at different procedures in the same animals with at least 15 days of interval. The BIS values were recorded during 60 seconds each time and mean values were obtained before (AE) and after (DE) the stimulus. Results were compared through paired t test or Wilcoxon's paired test (P 0.05). Significant differences were found between AE and DE values in almost every isoflurane concentration, as well as between the subtraction of these values, when compared between types of stimuli at 1.8 and 2.0%. In conclusion, the response to supra-maximal stimulation does change BIS values in dogs by decreasing the depth of anesthesia. The use of mechanical stimulation is suggested in order to avoid possible interferences of the electrical current and loss of data reliability.(AU)

Cardiopulmonary parameters in propofol- or thiopental-anesthetized dogs induced to pulmonary hypertension by serotonin / Parâmetros cardiopulmonares em cães anestesiados com propofol ou tiopental e induzidos à hipertensão pulmonar pela serotonina

The cardiopulmonary changes in propofol- or thiopental-anesthetized dogs induced to pulmonary hypertension (PH) were evaluated. Twenty adult animals were randomly assigned to two groups: propofol group (PG) and thiopental group (TG). In PG, propofol was used for induction (8(0.03mg.kg-1) and anesthesia maintenance (0.8mg.kg-1.minute-1), while, in TG, thiopental was used (22±2.92mg.kg-1; 0.5mg.kg-1.minute-1, respectively). Mechanical ventilation using time cycle was started. PH was induced by administration of serotonin (5HT) (10µg.kg-1 and 1mg.kg-1.hour-1) through a thermodilution catheter positioned in the pulmonary artery. The measurements were performed before administration of 5HT (T0), after 30 minutes (T30), then at 15-minute intervals (T45, T60, T75 and T90). No differences between groups were registered for systolic (sPAP) and mean pulmonary arterial pressure (mPAP), mean arterial pressure (MAP), total peripheral resistance index (TPRI) and pulmonary vascular resistance index (PVRI). In PG, sPAP and mPAP increased from T30. While in TG, sPAP and mPAP increased from T75. In PG, heart rate (HR) increased from T30, in which PG was higher than TG. The TPRI values decreased from T30 in PG, and in TG, at T45, T60 and T90. In PG, at T0, PVRI was lower than at other times. In PG, arterial partial pressures of oxygen (PaO2) decreased from T60 and alveolar-arterial oxygen gradient (PA-aO2) increased at T60. In TG, at T0 PaO2 was higher than at T30, T45, T60 and T90, while PA-aO2 at T0 was lower than at T90. From T30 to T90, TG showed higher PaO2 means and lower arterial partial pressures of carbon dioxide (PaCO2) values when compared to PG. In PG, from T30, PaCO2 increased, while in TG this parameter was stable. In conclusion, thiopental anesthesia attenuated the cardiopulmonary changes resulting from serotonin-induced PH, probably by attenuation of vasoconstriction and bronchoconstriction.(AU)

Avaliaram-se as alterações cardiopulmonares em cães anestesiados com propofol ou tiopental induzidos à hipertensão pulmonar (HP). Vinte animais adultos foram distribuídos aleatoriamente em dois grupos: grupo propofol (PG) e grupo tiopental (TG). No PG, o propofol foi usado para indução (8(0,03mg.kg-1) e manutenção da anestesia (0,8mg.kg-1minuto-1), enquanto no TG foi empregado o tiopental (22(2,92mg.kg-1; 0,5mg.kg-1.minute-1, respectivamente). Em seguida, a ventilação mecânica ciclada a tempo foi iniciada. A HP foi induzida pela administração de serotonina (5HT) (10µg.kg-1e 1mg.kg-1.hour-1) por meio de cateter de termodiluição posicionado na artéria pulmonar. As mensurações tiveram início antes da administração da 5HT (T0), depois de 30 minutos (T30), seguida de intervalos de 15 minutos (T45, T60, T75 e T90). Diferenças entre os grupos não foram registradas para pressões sistólica (PAPs) e média (PAPm) da artéria pulmonar, pressão arterial média (PAM), índices da resistência periférica total (IRPT) e da resistência vascular pulmonar (IRVP). A PAPs e a PAPm aumentaram a partir de T30, no PG, e a partir de T75, no TG. No PG, a frequência cardíaca (FC) aumentou a partir de T30, no qual PG foi maior que TG. O IRPT diminuiu no T45, T60 e T90, no TG, e a partir de T30 no PG. No PG, no T0, IRVP foi menor que nos outros momentos. No PG, a pressão parcial de oxigênio no sangue arterial (PaO2) diminuiu a partir de T60, e a diferença de tensão entre o oxigênio alveolar e arterial (PA-aO2) aumentou no T60. No TG, no T0, a PaO2 foi maior que no T30, T45, T60 e T90, enquanto a PA-aO2,, no T0, foi menor que no T90. Entre T30 e T90, TG apresentou maior PaO2 e menor pressão parcial de dióxido de carbono no sangue arterial (PaCO2) quando comparado ao PG. No PG, a partir de T30, a PaCO2 aumentou. A anestesia com tiopental abrandou as mudanças cardiopulmonares resultantes da indução da HP pela serotonina, provavelmente devido à atenuação da vasoconstrição e broncoconstrição.(AU)

Comparison of the depth of anesthesia produced with dexmedetomidine-sevoflurane or medetomidine-sevoflurane by using bispectral index monitoring

Background: Bispectral index (BIS) monitor was developed to utilize the depth of anesthesia by estimating electroencephalogram (EEG) signals. BIS, which is the numerical value of EEG derivative, is used for evaluation of depression of central nervous system (CNS) in human medicine. The depressive effect of sedative and anaesthetic agents on CNS in human is correlated to BIS. Dexmedetomidine (DEX) is administered as continuous infusion during anesthesia and surgery in humans. DEX is a hypnotic with high selectivity for 2-adrenergic receptors.Materials, Methods & Results: Adult female New Zealand rabbits (mean ± SD body weight 3.8 ± 0.5 kg) were procured from a certified commercial source to use in medical researches. The animal number in each of the two study groups was four, for a total of eight. The rabbits were randomly divided into two equal groups (n = 4). The rabbits DEX group were administered 20 mcg/kg of iv. DEX HCI for premedication. Medetomidine (MED) group was administered 20 mcg/ kg of iv MED for premedication. Induction was provided by 5% of sevoflurane + 4 L/min oxygen via glove mask in the both groups. General anesthesia was maintained with 3% of sevoflurane + oxygen on spontaneous respiration for 30 min. The animals temporomandibular region was shaved; its fat was eliminated with ether before the study. Human sensors were used as BIS sensor consisted of...(AU)

Comparison of the depth of anesthesia produced with dexmedetomidine-sevoflurane or medetomidine-sevoflurane by using bispectral index monitoring

Background: Bispectral index (BIS) monitor was developed to utilize the depth of anesthesia by estimating electroencephalogram (EEG) signals. BIS, which is the numerical value of EEG derivative, is used for evaluation of depression of central nervous system (CNS) in human medicine. The depressive effect of sedative and anaesthetic agents on CNS in human is correlated to BIS. Dexmedetomidine (DEX) is administered as continuous infusion during anesthesia and surgery in humans. DEX is a hypnotic with high selectivity for 2-adrenergic receptors.Materials, Methods & Results: Adult female New Zealand rabbits (mean ± SD body weight 3.8 ± 0.5 kg) were procured from a certified commercial source to use in medical researches. The animal number in each of the two study groups was four, for a total of eight. The rabbits were randomly divided into two equal groups (n = 4). The rabbits DEX group were administered 20 mcg/kg of iv. DEX HCI for premedication. Medetomidine (MED) group was administered 20 mcg/ kg of iv MED for premedication. Induction was provided by 5% of sevoflurane + 4 L/min oxygen via glove mask in the both groups. General anesthesia was maintained with 3% of sevoflurane + oxygen on spontaneous respiration for 30 min. The animals temporomandibular region was shaved; its fat was eliminated with ether before the study. Human sensors were used as BIS sensor consisted of...

Efeitos hemodinâmicos da anestesia em plano profundo com infusão intravenosa contínua de propofol ou propofol associado à lidocaína em cães / Hemodynamic effects of deep anesthesia with a constant rate infusion of propopol or propofol combined with lidocaine in dogs

Os efeitos hemodinâmicos da anestesia total intravenosa com propofol ou propofol associado à lidocaína foram estudados em 12 cães. No grupo P (n=6), os animais receberam bolus de 6mg kg-1 de propofol e infusão contínua de 1,25mg kg-1 min-1. No grupo PL (n=6), os animais receberam bolus de 6mg kg-1 de propofol e 1,5mg kg-1 de lidocaína, seguido de infusão de 1,0mg kg-1 min-1 e 0,25mg kg-1 min-1, dos mesmos fármacos, respectivamente. Os animais foram instrumentados para mensuração das variáveis hemodinâmicas e do índice bispectral (BIS), aos 75, 90, 105 e 120 minutos de anestesia. Foram observados valores menores de índice cardíaco, índice sistólico, pressões arteriais sistólica, diastólica e média no grupo P do que no grupo PL (P<0,05). Não foram observadas diferenças entre os grupos na frequência cardíaca, índice de resistência vascular sistêmica e BIS. As concentrações plasmáticas de propofol foram menores no grupo PL do que no grupo P (medianas de 5,7 a 6,1µg mL-1 no grupo P versus 3,1 a 3,7µg mL-1 no grupo PL). As concentrações plasmáticas de lidocaína (medianas de 2,27 a 2,51µg mL-1) mensuradas encontram-se na faixa que resulta em analgesia e abaixo de valores que resultam em toxicidade em cães. Os valores de BIS obtidos nos dois grupos foram compatíveis com plano profundo de anestesia (médias de 43 a 46 e 45 a 49 nos grupos P e PL, respectivamente). A manutenção da anestesia em plano profundo com lidocaína-propofol causa menor depressão cardiovascular do que a anestesia com dose equipotente de propofol isoladamente.(AU)

The hemodynamic effects of total intravenous anesthesia with propofol or propofol in combination with lidocaine were investigated in 12 dogs. In the P group (n=6), the dogs received a loading dose (LD) of 6mg kg-1 of propofol followed by a constant rate infusion (CRI) of 1.25mg kg-1 min-1. In the PL group (n=6), dogs received a LD of 6mg kg-1 of propofol and 1.5mg kg-1 of lidocaine followed by CRIs of 1.0mg kg-1 min-1 and 0.25mg kg-1 min-1 of propofol and lidocaine, respectively. The animals were instrumented for measurement of hemodynamic variables and bispectral index (BIS), recorded at 75, 90, 105 and 120 minutes during anesthesia. Cardiac index, stroke index, systolic, diastolic and mean arterial blood pressures were lower in the P group compared to the PL group (P<0.05). There were no significant differences between groups in heart rate, systemic vascular resistance index and BIS. Plasma concentrations of propofol were lower in group PL than in group P (medians of 5.7 to 6.1mg mL-1 in the P group versus 3.1 to 3.7mg mL-1 in the PL group). Measured lidocaine plasma concentrations (medians of 2.27 to 2.51mg mL-1) were in the range that result in analgesia and were below values that result in toxicity in dogs. The BIS values observed in the two groups of dogs were compatible with deep anesthesia (mean values of 43-46 and 45-49 in groups P and PL, respectively). Maintenance of deep anesthesia with lidocaine-propofol causes less cardiovascular depression than equipotent doses of propofol alone.(AU)

Effects of continuous rate infusion of butorphanol in isoflurane-anesthetized calves

PURPOSE: To assess the hemodynamic changes and bispectral index (BIS) following administration of a continuous rate infusion (CRI) of butorphanol in isoflurane-anesthetized calves. METHODS: Eight calves weighing 110 ± 12 kg were included in the study. Anesthesia was induced with 5% isoflurane in O2 delivered via face mask and maintained with end-tidal concentration of 1.4%. IPPV was set to a peak inspiratory airway pressure of 15 cmH2O and respiratory rate of six breaths minute-1. Forty minutes after the start of anesthetic maintenance, 0.1 mg kg-1butorphanol was administered intravenously, followed by a CRI of 20 µg kg-1 minute-1. Hemodynamic variables and BIS were recorded before butorphanol administration (T0), and at 10, 20, 40 and 80 minutes following the CRI. Anesthesia was discontinued after the last recording and the calves were allowed to recover. The time to sternal recumbency (SRE) and standing (ST) were evaluated. RESULTS: There were no significant differences between the moments in all hemodynamic variables and BIS. The time to SRE and ST was 9 ± 5 and 14 ± 7 minutes, respectively. CONCLUSION: The continuous rate infusion did not produce clinically relevant changes in hemodynamic or bispectral index values compared to baseline in mechanically ventilated and unstimulated calves anesthetized at 1.4% isoflurane. (AU)

Comparison of bispectral index and vital parameters in rabbits receiving propofol or isoflurane anesthesia / Comparison of bispectral index and vital parameters in rabbits receiving propofol or isoflurane anesthesia

Background: Reflexes, muscle tonus, heart rate, respiratory frequency and blood pressure are parameters that can be used to evaluate the depth of anesthesia. Bispectral index (BIS) was developed with the objective of evaluating quantitatively the sedative and hypnotic effects of anesthetic drugs. It is widely used to assess central nervous system depression levels. The objective of this study was to compare changes in BIS and several vital parameters during general anesthesia achieved with either propofol or isoflurane, following premedication with dexmedetomidine. Materials, Methods & Results: Adult female New Zealand rabbits (Mean ± SD body weight 3.6 ± 0.4 kg) were procured from a commercial source certified for medical experimentation. The animal number in each of the two study groups was four, for a total of eight. The animals were checked before the study to ascertain their good health. The animals, randomly allocated to either of two study groups, were given dexmedetomidine, 20 µg/kg i.v. Induction was realized by means of propofol, 8 mg/kg i.v. in the propofol group (n = 4), and by administration through a glove mask of isoflurane, 4%, in the isoflurane group (n = 4). Anesthesia maintenance was assured by propofol, 0.6 mg/kg/min or 2% isoflurane with oxygen, respectively. Both anesthetic applications were well tolerated by the rabbits. Before premedication (T0), at

Background: Reflexes, muscle tonus, heart rate, respiratory frequency and blood pressure are parameters that can be used to evaluate the depth of anesthesia. Bispectral index (BIS) was developed with the objective of evaluating quantitatively the sedative and hypnotic effects of anesthetic drugs. It is widely used to assess central nervous system depression levels. The objective of this study was to compare changes in BIS and several vital parameters during general anesthesia achieved with either propofol or isoflurane, following premedication with dexmedetomidine. Materials, Methods & Results: Adult female New Zealand rabbits (Mean ± SD body weight 3.6 ± 0.4 kg) were procured from a commercial source certified for medical experimentation. The animal number in each of the two study groups was four, for a total of eight. The animals were checked before the study to ascertain their good health. The animals, randomly allocated to either of two study groups, were given dexmedetomidine, 20 µg/kg i.v. Induction was realized by means of propofol, 8 mg/kg i.v. in the propofol group (n = 4), and by administration through a glove mask of isoflurane, 4%, in the isoflurane group (n = 4). Anesthesia maintenance was assured by propofol, 0.6 mg/kg/min or 2% isoflurane with oxygen, respectively. Both anesthetic applications were well tolerated by the rabbits. Before premedication (T0), at

Infusão contínua de morfina ou fentanil, associados à lidocaína e cetamina, em cães anestesiados com isofluorano / Continuous infusion of morphine or fentanyl, associated to lidocaine and ketamine, in isofluorane-anesthetized dogs

A técnica de analgesia multimodal, por meio da infusão contínua de fármacos, pode ser empregada para diminuir a incidência de sensibilização central durante a anestesia. Avaliaram-se as características cardiorrespiratórias, durante o procedimento de artroscopia de joelho, em cães anestesiados com isofluorano e monitorados por meio do índice biespectral, submetidos à infusão contínua de morfina ou fentanil, associada à lidocaína e cetamina. Utilizaram-se 16 cães adultos, machos ou fêmeas, os quais foram distribuídos aleatoriamente em dois grupos, denominados MLK - que recebeu morfina (3,3μg/kg/min), lidocaína (50μg/kg/min) e cetamina (10μg/kg/min) ou FLK - em que foi substituída a morfina pelo fentanil (0,03μg/kg/min). Os cães foram pré-tratados com levomepromazina (0,5mg/kg IV), induzidos à anestesia com propofol (5mg/kg) e mantidos com isofluorano, ajustando-se a concentração para obterem-se valores de índice biespectral entre 55 e 65. As mensurações da frequência cardíaca (FC), dos parâmetros eletrocardiográficos (ECG), das pressões arteriais sistólica (PAS), diastólica (PAD) e média (PAM), da tensão de dióxido de carbono expirado (EtCO2), da saturação de oxi-hemoglobina (SpO2), da frequência respiratória (FR) e da temperatura esofágica (T) iniciaram-se 30 minutos após a indução (M0) e continuaram após o início da infusão das soluções, em intervalos de 15 minutos (M15 a M75). Diferenças entre os grupos foram registradas para duração do complexo QRS (M60), para FC e T, entre M30 e M75, com MLK apresentando médias maiores que FLK, que registrou médias maiores que MLK para a SpO2 (M60), para os intervalos QT (M30 e M75) e RR (M0, M60 e M75). Concluiu-se que o emprego de morfina ou fentanil, associados à lidocaína e cetamina, promove efeitos semelhantes e não compromete as características avaliadas.(AU)

The multimodal analgesia technique by continuous infusion of drugs can be used to decrease central sensitization during anesthesia. Cardiorespiratory parameters in isofluorane-anesthetized dogs during joint arthroscopy were evaluated. For this, 16 adult mongrel dogs were randomly divided into two groups, named MLK (morphine (3.3mg/kg/min), lidocaine (50μg/kg/min) and ketamine (10mg/kg/min)) or FLK (replacing morphine by fentanyl (0.03mg/kg/min). Levomepromazine (0.5mg/kg IV) was used as a preanesthetic medication, and propofol (5mg/kg IV) was used for induction and isoflurane was used for maintained general anesthesia, allowing the bispectral index to be maintained between 55 and 65. The measurements of heart rate (HR), eletrocardiographic, systolic (SAP), diastolic (DAP) and mean (MAP) arterial pressures, end-tidal carbon dioxide partial pressure (ETCO2), pulse oxygen saturation (SpO2) respiratory rate (RR) and esophageal temperature (T) were performed 30 minutes after induction (M0), and after the infusion of solutions, at 15 minute intervals (M15 to M75). Differences between groups were registered for the duration of the QRS complex (M60), for HR and T (from M30 to M75), with MLK recording a higher mean than FLK, which registered a lower value than MLK for SpO2 (M60), QT (M30 and M75) and RR (M0, M60 and M75) intervals. It was concluded that morphine or fentanyl, associated with lidocaine and ketamine, promotes similar effects and does not impair the parameters evaluated.(AU)

Comparison of bispectral index and vital parameters in rabbits receiving propofol or isoflurane anesthesia

Background: Reflexes, muscle tonus, heart rate, respiratory frequency and blood pressure are parameters that can be used to evaluate the depth of anesthesia. Bispectral index (BIS) was developed with the objective of evaluating quantitatively the sedative and hypnotic effects of anesthetic drugs. It is widely used to assess central nervous system depression levels. The objective of this study was to compare changes in BIS and several vital parameters during general anesthesia achieved with either propofol or isoflurane, following premedication with dexmedetomidine. Materials, Methods & Results: Adult female New Zealand rabbits (Mean ± SD body weight 3.6 ± 0.4 kg) were procured from a commercial source certified for medical experimentation. The animal number in each of the two study groups was four, for a total of eight. The animals were checked before the study to ascertain their good health. The animals, randomly allocated to either of two study groups, were given dexmedetomidine, 20 µg/kg i.v. Induction was realized by means of propofol, 8 mg/kg i.v. in the propofol group (n = 4), and by administration through a glove mask of isoflurane, 4%, in the isoflurane group (n = 4). Anesthesia maintenance was assured by propofol, 0.6 mg/kg/min or 2% isoflurane with oxygen, respectively. Both anesthetic applications were well tolerated by the rabbits. Before premedication (T0), at the time points of 1 (T1) and 5 min (T2) after dexmedetomidine injection, 1 min into anesthesia induction (T3), and 10 (T4), 30 (T5) and 60 min (T6) after start of maintenance, the following were recorded: BIS, systolic, diastolic and mean arterial blood pressure, heart rate and Anesthesia Score (AS). Blood gas analysis, serum sodium and potassium, blood glucose level, hemoglobin and hematocrit were measured at time points T0 and T6. MAP dropped significantly lower in the propofolgroup at times T2, T3 and T4 (P < 0.05). Under BIS monitoring, BIS values were also found to be relatively lower in the propofol group at times T1, T2 and T4, corresponding in this to AS. At T4, the BIS values were, respectively, 69.5 ± 6.24 and 68.25 ± 3.59 in the isoflurane and propofol groups (P < 0.05). In summary, premedication with dexmedetomidine did not, differently than with humans, assure deep sedation; BIS values, in parallel with our AS evaluation, reached levels of deep anesthesia in the maintenance stage both in the propofol and isoflurane groups. BGA results in arterial blood (pH, PaO2, PaCO2, BE, HCO3) as well as hematocrit (Hct), Na+, K+, glucose, hemoglobin (Hb) were recorded and reported in Table 2. A significant increase in pH was noted at T6 (P < 0.05) in the propofol groups compared to animals given isoflurane (7.39 ± 0.01 vs 7.35 ± 0.003, respectively), all measurements remaining within the normal values. Discussion: Vital parameters showed parallelism with the values of both our AS and BIS in this study, in which we administered general anesthesia with either propofol or isoflurane to rabbits premedicated with dexmedetomidine. Publications on humans show that surgical anesthesia is realized at BIS values under 60; BIS fell in rabbits in parallel to MBP at 10, 30 and 60 min of anesthesia, and AS also showed that the depth of anesthesia was adequate. No surgery having been performed in this study, we think that the parameters noted in this paper should be investigated in future studies that include surgery.

Efeitos da associação de tiletamina/zolazepam ou cetamina S(+)/midazolam/tramadol para contenção química em bugios-ruivos (Allouatta guariba clamitans) / Effects of tiletamine/zolazepam or S(+) ketamine/midazolam/tramadol for chemical contention in red howler monkeys (Allouatta guariba clamitans)

Two protocols for chemical restraint in howler-redheads were evaluated. We used 12 healthy red howler monkeys, weighing 6.4±0.4 kg, which were fasted and without water six and two hours, respectively. The animals were divided into two groups that received intramuscular injection: TZ (n=6) which received tiletamine-zolazepam (Zoletil®) at a dose of 3.6mg/kg and CEMTRA (n=6) which received ketamine S (+), tramadol and midazolan (Cemtra®, pilot batch 001/10, Ouro Fino Saúde Animal Ltda, Cravinhos/SP, Brazil, comprising 100mg/ml of ketamine S (+), tramadol 20mg/ml and 10mg/ml of midazolam) in dose of 1ml of the association for each 10kg of body weight, equivalent doses of 10mg/kg, 1mg/kg and 2mg/kg, respectively. Prior to administration of drugs (M0) were evaluated: heart rate (HR), respiratory rate (RR), rectal temperature (RT), capillary refill time (CRT), systolic arterial pressure (SAP), hemoglobin oxygen saturation (SpO2 ), presence of salivation, degree of muscle relaxation and sedation, Bispectral index (BIS) and Signal Quality BIS (SQI), interdigital pinch response and latency times, ambulation and total recovery (TRT). The parameters were reassessed M5, M10, M20, M30, M40 and M50 (5, 10, 20, 30, 40 and 50 minutes after drug administration). In TZ animals were more responsive to the interdigital pinch over time. The animals of CEMTRA showed a higher degree of muscle relaxation and sedation. The RR of CEMTRA was lower after administration of treatment at all times in relation to M0. Among the groups RR of CEMTRA was lower compared to the TZ in M2 and M4. The total time of sedation and recovery was 48±4 min and 150.1±42.1 for the CEMTRA and 38±7 and 73.1±20.6 for the TZ. We conclude that both formulations are safe for containing chemical howler, and the CEMTRA showed better sedation and muscle relaxant.(AU)

Avaliaram-se dois protocolos para contenção química em bugios-ruivos. Para tal, foram utilizados 12 macacos bugios, hígidos, com peso médio de 6,4±0,4 kg, os quais foram submetidos a jejum alimentar e hídrico de seis e duas horas, respectivamente. Os animais foram alocados em dois grupos que receberam injeção via intramuscular: TZ (n=6), os quais receberam uma associação de tiletamina e zolazepam (Zoletil®) na dose de 3,6mg/kg e CEMTRA (n=6), que receberam cetamina S(+), midazolam e tramadol (Cemtra ®, lote piloto 001/10, Ouro Fino Saúde Animal Ltda., Cravinhos, SP-Brasil, constituído por 100mg/ml de cetamina S+, 20mg/ml de tramadol e 10mg/ml de midazolam) na dose de 1ml da associação para cada 10kg de peso corporal, correspondendo às doses de 10mg/kg, 1mg/kg e 2mg/kg, respectivamente. Anteriormente a administração dos fármacos (M0) foram avaliadas: frequência cardíaca (FC) e respiratória (f), temperatura retal (TR), tempo de preenchimento capilar (TPC), pressão arterial sistólica (PAS), saturação de oxigênio na hemoglobina (SpO2), presença de salivação, grau de miorrelaxamento e sedação, índice Bispectral (BIS) e Sinal de Qualidade do BIS (SQI), resposta ao pinçamento interdigital e tempos de latência, deambulação e de recuperação total (TRT). Os parâmetros foram reavaliados em M5, M10, M20, M30, M40 e M50 (5, 10, 20, 30, 40 e 50 minutos após a administração dos fármacos). No TZ os animais foram mais responsivos ao pinçamento interdigital ao longo dos tempos. Os animais do CEMTRA apresentaram maior grau de miorrelaxamento e de sedação. A f do CEMTRA foi menor após a administração do tratamento em todos os momentos em relação ao M0. Entre grupos a f do CEMTRA foi menor em relação ao TZ em M2 e M4. Os tempos totais de sedação e de recuperação foram de 48±4 e 150,1±42,1 min para o CEMTRA e de 38±7 e 73,1±20,6 para o TZ. Conclui-se que ambas as formulações são seguras para contenção química de bugios, sendo que o CEMTRA apresentou melhor sedação e miorrelaxamento.(AU)

INTERFERÊNCIA DA HIPOXEMIA NA AVALIAÇÃO DO NÍVEL DE CONSCIÊNCIA PELO ÍNDICE BISPECTRAL EM CAVALOS ANESTESIADOS COM PROPOFOL OU ISOFLUORANO

O índice bispectral (BIS) é um parâmetro derivado do eletroencefalograma que permite a monitoração da profundidade anestésica de forma quantitativa. Embora sua utilização seja ampla na medicina, seu uso é limitado na medicina veterinária, havendo diferentes resultados quanto a sua aplicabilidade, inclusive em cavalos. A hipoxemia não é uma complicação incomum na anestesia equina, podendo levar a alterações do BIS de forma que este não reflita corretamente o componente hipnótico da anestesia. Este estudo teve como objetivos comparar o índice bispectral e a avaliação clínica da profundidade anestésica em cavalos anestesiados com isofluorano ou propofol e avaliar a influência da hipoxemia nos valores do BIS em cavalos submetidos a hipoxemia por ventilação monopulmonar. Foram utilizados seis animais submetidos a anestesia para toracoscopia. Após pré-medicação com xilazina e indução anestésica com propofol e guaiafenesina, a anestesia foi mantida com propofol (PRO) ou isofluorano (ISO) sendo a taxa de infusão e a fração expirada dos anestésicos alteradas segundo avaliação clínica da profundidade anestésica. O BIS foi avaliado nos animais acordados, após 10 minutos de sedação, a cada 10 minutos durante a manutenção da anestesia, no início do despertar e no momento da extubação. Foram avaliados parâmetros cardiovasculares e respiratórios, variáveis hemodinâmicas e de oxigenação tecidual durante a anestesia. Os valores médios de BIS foram 97±1 para animais acordados e 80±6 para animais sedados, havendo diferença significativa entre estes e entre os animais anestesiados (p<0,05). Para os planos superficial, adequado e profundo de anestesia o BIS foi 68±1, 67±10 e 59±7, respectivamente, sendo o BIS no plano profundo significativamente menor quando comparado ao plano superficial (p=0,014) No inicio do despertar o BIS foi de 79±8 e de 87±6 no momento da extubação, valor significativamente mais alto quando comparado aos animais anestesiados. A hipoxemia levou a aumento significativo nos valores de BIS de 59±6 para 65±7 (p=0,012), acompanhado de aumento na FC, PAM e EMG no PRO. O BIS pode ser utilizado para diferenciar planos mais profundos de anestesia em cavalos, em especial quando anestesiados com isofluorano, e na percepção do despertar em cavalos anestesiados com propofol ou isofluorano. A hipoxemia ocasionar o aumento nos valores de BIS decorrente da ativação simpática e aumento da EMG em cavalos anestesiados com propofol.

Bispectral index (BIS) is an electroencephalogram derivated parameter which allows depth of anesthesia monitoring in an objective way. Althought it has a widespread use in medicine, its use in veterinary medicine is limitated, with different results regarding its applicability, including horses. Hypoxemia is not an uncommon complication during equine anesthesia and may lead to BIS changes so that it does not accurately reflect the hypnotic component of anesthesia. The objectives of this study were to compare the bispectral index and clinical evaluation of anesthetic depth in horses anesthetized with isoflurane or propofol; and to evaluate the influence of hypoxemia on BIS values in horses submitted to hypoxemia by monopulmonary ventilation. It were used six horses undergoing anesthesia for thoracoscopy. After premedication with xylazine and anesthetic induction with propofol and guaiafenesin, anesthesia was maintained with propofol (PRO) or isoflurane (ISO) and the infusion rate and the expired fraction of the anesthetics were altered according to clinical evaluation of anesthetic depth. The BIS was evaluated in the awake animals, 10 minutes after sedation, every 10 minutes during anesthesia maintenance, at the beginning of the awakening and at the time of extubation. Cardiovascular and respiratory parameters, hemodynamic variables and tissue oxygenation were evaluated during anesthesia. The mean values of BIS were 97 ± 1 for awake animals and 80 ± 6 for sedated animals, with a significant difference between these and between anesthetized animals (p <0.05). For the superficial, adequate and deep planes of anesthesia the BIS was 68 ± 1, 67 ± 10 and 59 ± 7, respectively, and the BIS in the deep plane was significantly smaller when compared to the superficial plane (p= 0.014). BIS was 79 ± 8 and 87 ± 6 at the time of extubation, a significantly higher value when compared to anesthetized animals. Hypoxemia led to a significant increase in BIS values from 59 ± 6 to 65 ± 7 (p =0.012), accompanied by an increase in HR, MAP and EMG in the PRO. BIS can be used to differentiate deeper planes of anesthesia in horses, especially when anesthetized with isoflurane, and in the perception of awakening in horses anesthetized with propofol or isoflurane. Hypoxemia may lead to increased BIS values due to sympathetic activation and increased EMG in horses anesthetized with propofol.

DIFERENTES FRAÇÕES INSPIRADAS DE OXIGÊNIO ASSOCIADO AO AR COMPRIMIDO OU ÓXIDO NITROSO, EM LEITÕES ANESTESIADOS COM PROPOFOL E MANTIDOS SOB VENTILAÇÃO CONTROLADA E PEEP

Compararam-se os efeitos de diferentes frações inspiradas de oxigênio (FiO2) associado ao óxido nitroso (N2O) ou ao ar comprimido sobre a hematose, parâmetros cardiorrespiratórios, intracranianos e o índice biespectral (BIS), em leitões mantidos em ventilação espontânea ou controlada a pressão, associada ou não à PEEP (5 cmH2O). Foram utilizados 48 leitões, distribuídos em 6 grupos, submetidos à 10, 30 e 50% de ar comprimido (GA10, GA30 e GA50) ou N2O (GN10, GN30 e GN50), associadas às FiO2 de 0,9, 0,7 e 0,5, respectivamente. O GA30 mostrou maior proximidade do intervalo fisiológico da pressão parcial de oxigênio no sangue arterial. A PEEP não foi eficaz na pressão parcial de dióxido de carbono no sangue arterial, independente da FiO2, quando se utilizou o N2O. O pH, déficit base e bicarbonato no sangue arterial foram influenciados pela FiO2 e N2O. As alterações do volume corrente e volume minuto parecem correlacionadas à introdução da ventilação mecânica (VM) e PEEP. Na diferença alvéolo-arterial de oxigênio, a PEEP influenciou negativamente o GA30 e GN30 e não foi adequada para manutenção do shunt pulmonar. Já a pressão média da artéria pulmonar e pressão média capilar pulmonar apresentaram acréscimos após introdução da PEEP. A associação da PEEP com N2O (50%) ou ar comprimido (50%) parece ser a receita para desempenho inferior da variação de pressão de pulso. Para a pressão intracraniana, apenas o GN30 apresentou valor menor ao se instituir a VM quando comparado com o momento em que houve início do auxílio com a PEEP. Concluiu-se que, nenhuma concentração de N2O é segura para a manutenção dos parâmetros hemogasométricos. A VM e a PEEP não são eficientes para manutenção das variáveis respiratórias. A PEEP promove piora no desempenho de parâmetros cardiovasculares e intracranianos. Maiores taxas de oferta de N2O (50%) reduzem o BIS em suínos.

The effects of different fractions of inspired oxygen (FiO2) associated with compressed air or nitrous oxide (N2O) on lung oxygenation, cardiorespiratory parameters, intracranial parameters and the bispectral index (BIS) were compared in piglets maintained under spontaneous or controlled ventilation, with or without PEEP (5 cmH2O). Forty-eight piglets, distributed in six groups, were submitted to 10, 30 and 50% of compressed air (GA10, GA30 and GA50) or N2O (GN10, GN30 and GN50), associated with FiO2 of 0.9, 0.7 and 0.5, respectively. GA30 showed greater proximity to the physiological range of partial oxygen pressure in the arterial blood. When N2O was used, PEEP was ineffective in maintaining partial carbon dioxide pressure in the arterial blood, independent of FiO2. Arterial blood pH, base deficit and bicarbonate were influenced by FiO2 and N2O. Changes in tidal and minute volumes seem to correlate with the introduction of mechanical ventilation (MV) and PEEP. The difference in alveolar-arterial oxygen under PEEP negatively influenced GA30 and GN30 and was inadequate for pulmonary shunt maintenance. Mean pulmonary artery pressure and mean capillary pulmonary pressure increased following the initiation of PEEP. The association of PEEP with N2O (50%) or compressed air (50%) seems to result in lower performance of pulse pressure variation. Regarding intracranial pressure, only GN30 presented a lower value when MV was established compared with the time point when PEEP was initiated. In conclusion, no concentration of N2O is safe for maintaining blood gas parameters. MV and PEEP are inefficient in the maintenance of respiratory variables. PEEP promotes deterioration in the performance of cardiovascular and intracranial parameters. Higher N2O supply rates (50%) reduce BIS in pigs.

Índice biespectral em cães com pressão intracraniana elevada, anestesiados com propofol e submetidos a dois níveis de FiO2 / Bispectral index in dogs with high intracranial pressure, anesthetized with propofol and submitted to two levels of FiO2

The effects of inspired oxygen fractions (FiO2) of 1 and 0.6 on bispectral index (BIS) in dogs with high intracranial pressure, submitted to a continuous rate infusion of propofol were evaluated. Eight dogs were anesthetized on two occasions, receiving, during controlled ventilation, an FiO2 = 1 (G100) or an FiO2 = 0.6 (G60). Propofol was used for induction (10mg.kg-1, IV), followed by a continuous rate infusion (0.6mg.kg-1.minute-1). After 20 minutes, a fiber-optic catheter was implanted on the surface of the right cerebral cortex to monitor the intracranial pressure, the baseline measurements of BIS values, signal quality index, suppression ratio number, electromyogram indicator, end-tidal carbon dioxide partial pressure, mean arterial pressure, intracranial pressure and cerebral perfusion pressure were taken. Then, the blood flow from the right jugular vein was interrupted in order to increase intracranial pressure and after 20 minutes additional recordings were performed at 15-minute intervals (T0, T15, T30, T45 and T60). The arterial oxygen partial pressure varied according to the changes in oxygen. For the other parameters, no significant differences were recorded. The BIS monitoring was not influenced by different FiO2.(AU)

Avaliaram-se os efeitos das frações inspiradas de oxigênio (FiO2) de 1 e 0,6 sobre o índice biespectral (BIS) em cães com pressão intracraniana elevada e submetidos a infusão contínua de propofol. Oito animais foram anestesiados em duas ocasiões, recebendo durante a ventilação controlada FiO2 = 1(G100) ou FiO2 = 0,6 (G60). Propofol foi usado para indução (10mg.kg-1) e seguido por infusão contínua (0,6mg.kg-1minuto-1). Após vinte minutos da implantação do cateter de fibra óptica do monitor de pressão intracraniana, na superfície do córtex cerebral direito, realizaram-se as mensurações basais de BIS, índice de qualidade de sinal, taxa de supressão, eletromiografia, pressão parcial de dióxido de carbono ao final da expiração, pressão arterial média, pressão intracraniana e pressão de perfusão cerebral. Em seguida, interrompeu-se o fluxo sanguíneo da veia jugular direita, para o aumento da pressão intracraniana e depois de 20 minutos, novas mensurações foram realizadas em intervalos de 15 minutos (T0, T15, T30, T45 e T60). A pressão parcial de oxigênio no sangue arterial variou conforme a FiO2. Para os outros parâmetros não foram registradas diferenças significativas. Conclui-se que o monitoramento pelo BIS não foi afetado pelo emprego de diferentes FiO2.(AU)

ÍNDICE BIESPECTRAL, EFEITOS HEMODINÂMICOS E RESPIRATÓRIOS DA INFUSÃO CONTÍNUA DE PROPOFOL ASSOCIADO OU NÃO AO FENTANIL EM BEZERROS

O estudo teve por objetivo avaliar o índice biespectral e os efeitos hemodinâmicos, respiratórios e hemogasométricos da infusão contínua de propofol associado ou não ao fentanil em bezerros. Foram utilizados oito animais machos entre seis e doze meses de idade, holandeses, com massa corporal média de 123 ± 18 kg. Todos os animais participaram de ambos os grupos, respeitando-se sempre um intervalo mínimo de uma semana entre uma anestesia e outra, os bezerros foram aleatoriamente distribuídos entre os grupos. Os animais foram induzidos à anestesia com propofol na dose de 5 mg/kg; IV, grupo controle (GP) ou propofol 4 mg/kg associado ao fentanil 0,001 mg/kg; IV, grupo fentanil (GF) e posicionados em decúbito lateral direito, onde permaneceram respirando espontaneamente ar ambiente. Ato contínuo, a manutenção anestésica foi realizada pela infusão contínua de propofol na taxa de 0,6 mg/kg/minuto; IV, associado ou não à infusão de fentanil 0,001 mg/kg/hora. Em ambos os grupos os fármacos foram administrados por meio de bomba de infusão durante 60 minutos. A mensuração das variáveis hemodinâmicas (FC, PAS, PAD, PAM, DC, PVC, PAPm, PAPOm, IC, IS, IRVS e IRVP), respiratórias (ETCO2, f, SpO2, VTE e VME), hemogasométricas (PaO2, PaCO2, SaO2, DB, pH e HCO3-) e indice bispectral (BIS, IQS e EMG) foi feita antes da indução anestésica (MB), e 15, 30,45 e 60 minutos após o início da infusão contínua dos fármacos (M15, M30, M45 e M60, respectivamente). Os parâmetros hemodinâmicos mantiveram-se estáveis durante o período de avalição, não foram observadas diferenças significativas entre os grupos nas variáveis respiratórias ou no BIS, porém, todos os animais apresentaram depressão respiratória e acidose. Com a infusão de propofol associado ou não ao fentanil obteve-se manutenção satisfatória dos parâmetros hemodinâmicos com depressão respiratória, indicando, portanto, a necessidade do emprego de ventilação controlada.

The aim of this study was to evaluate the bispectral index and hemodynamic, respiratory and blood gas effects of continuous infusion of propofol with or without fentanyl in calves. Eight animals were used, with six to 12 months old, male Holstein calves, with an average weight of 123 ± 18 kg. All animals participated in both groups, respecting always a minimum interval of one week between the anesthetic procedures, the calves were randomly distributed between groups. They were induced to anesthesia with propofol at a dose of 5 mgkg-1 IV control group (GP) or propofol 4 mg kg-1 associated with fentanyl 0.001mgkg-1 IV fentanyl group (GF) and positioned in right lateral decubitus, where remained spontaneously breathing room air. Subsequently, the Anesthesia was maintained by continuous infusion of propofol at the rate of 0.6 mg kg-1 min-1 IV, with or without the infusion of fentanyl 0.001mg kg-1 hour-1. In both groups, drugs were administered through an infusion pump over 60 minutes. The measurements of hemodynamic parameters (HR, SAP, DAP, MAP, CO, CVP, mPAP, mPAPO, CI, SI, SVRI and PVRI), respiratory (ETCO2, f, SpO2,VME and VTE), blood gas(PaO2, PaCO2, SaO2, DB, pHandHCO3-) and bispectral index (BIS, SQI and EMG) were evaluated before anesthesia induction(MB), 15, 30, 45 and 60 minutes after the beginning of continuous infusion of drugs (M15, M30, M45 and M60, respectively). Hemodynamic parameters remained stable during the evaluate on period, no significant differences were observed between the groups in the respiratory variables and BIS, however, all animals presented respiratory acidosis. With the infusion of propofol associated or not with fentanyl the maintenance of the hemodynamic parameters was satisfactory with respiratory acidosis indicating, therefore, the use of mechanical ventilation.

COMPARAÇÃO ENTRE MISTURAS DE EXTRATOS PROTEICOS EM AVES COM INTERESSE COMERCIAL

O estudo teve por objetivo avaliar o índice biespectral e os efeitos hemodinâmicos, respiratórios e hemogasométricos da infusão contínua de propofol associado ou não ao fentanil em bezerros. Foram utilizados oito animais machos entre seis e doze meses de idade, holandeses, com massa corporal média de 123 ± 18 kg. Todos os animais participaram de ambos os grupos, respeitando-se sempre um intervalo mínimo de uma semana entre uma anestesia e outra, os bezerros foram aleatoriamente distribuídos entre os grupos. Os animais foram induzidos à anestesia com propofol na dose de 5 mg/kg; IV, grupo controle (GP) ou propofol 4 mg/kg associado ao fentanil 0,001 mg/kg; IV, grupo fentanil (GF) e posicionados em decúbito lateral direito, onde permaneceram respirando espontaneamente ar ambiente. Ato contínuo, a manutenção anestésica foi realizada pela infusão contínua de propofol na taxa de 0,6 mg/kg/minuto; IV, associado ou não à infusão de fentanil 0,001 mg/kg/hora. Em ambos os grupos os fármacos foram administrados por meio de bomba de infusão durante 60 minutos. A mensuração das variáveis hemodinâmicas (FC, PAS, PAD, PAM, DC, PVC, PAPm, PAPOm, IC, IS, IRVS e IRVP), respiratórias (ETCO2, f, SpO2, VTE e VME), hemogasométricas (PaO2, PaCO2, SaO2, DB, pH e HCO3-) e indice bispectral (BIS, IQS e EMG) foi feita antes da indução anestésica (MB), e 15, 30,45 e 60 minutos após o início da infusão contínua dos fármacos (M15, M30, M45 e M60, respectivamente). Os parâmetros hemodinâmicos mantiveram-se estáveis durante o período de avalição, não foram observadas diferenças significativas entre os grupos nas variáveis respiratórias ou no BIS, porém, todos os animais apresentaram depressão respiratória e acidose. Com a infusão de propofol associado ou não ao fentanil obteve-se manutenção satisfatória dos parâmetros hemodinâmicos com depressão respiratória, indicando, portanto, a necessidade do emprego de ventilação controlada

The aim of this study was to evaluate the bispectral index and hemodynamic, respiratory and blood gas effects of continuous infusion of propofol with or without fentanyl in calves. Eight animals were used, with six to 12 months old, male Holstein calves, with an average weight of 123 ± 18 kg. All animals participated in both groups, respecting always a minimum interval of one week between the anesthetic procedures, the calves were randomly distributed between groups. They were induced to anesthesia with propofol at a dose of 5 mgkg-1 IV control group (GP) or propofol 4 mg kg-1 associated with fentanyl 0.001mgkg-1 IV fentanyl group (GF) and positioned in right lateral decubitus, where remained spontaneously breathing room air. Subsequently, the Anesthesia was maintained by continuous infusion of propofol at the rate of 0.6 mg kg-1 min-1 IV, with or without the infusion of fentanyl 0.001mg kg-1 hour-1. In both groups, drugs were administered through an infusion pump over 60 minutes. The measurements of hemodynamic parameters (HR, SAP, DAP, MAP, CO, CVP, mPAP, mPAPO, CI, SI, SVRI and PVRI), respiratory (ETCO2, f, SpO2,VME and VTE), blood gas(PaO2, PaCO2, SaO2, DB, pHandHCO3-) and bispectral index (BIS, SQI and EMG) were evaluated before anesthesia induction(MB), 15, 30, 45 and 60 minutes after the beginning of continuous infusion of drugs (M15, M30, M45 and M60, respectively). Hemodynamic parameters remained stable during the evaluate on period, no significant differences were observed between the groups in the respiratory variables and BIS, however, all animals presented respiratory acidosis. With the infusion of propofol associated or not with fentanyl the maintenance of the hemodynamic parameters was satisfactory with respiratory acidosis indicating, therefore, the use of mechanical ventilation.

Hemodynamics and bispectral index (BIS) of dogs anesthetized with midazolam and ketamine associated with medetomidine or dexmedetomidine and submitted to ovariohysterectomy / Avaliação hemodinâmica e do índice bispectral (BIS) de cadelas anestesiadas com midazolam e cetamina associados à medetomidina ou dexmedetomidina e submetidas a ovário-salpingo-histerectomia

Purpose: To evaluate hemodynamics and bispectral index (BIS) in bitches anesthetized with ketamine and midazolam in combination with dexmedetomidine or medetomidine and submitted to ovariohysterectomy. Methods: Twenty bitches pretreated with levomedetomidine and buprenorphine were anesthetized with 5 mg.kg-1 ketamine and 0.2 mg.kg-1 midazolam i.v. Continuous infusion of 0.4 mg.kg-1.h-1 midazolam and 20 mg.kg-1.h-1 ketamine was initiated in combination with DEX (n=10): 20 µg.kg-1.h-1 dexmedetomidine or MED (n=10): 30 µg.kg-1.h-1 medetomidine over 30 minutes. A pharmacokinetic study provided dexmedetomidine plasma concentration, set to be 3.0 ng.mL-1. Results: BIS decreased in both groups (P<0.05), but it was lower in DEX (P<0.05) as compared to MED. No differences were found in hemodynamic parameters (heart rate, systolic, diastolic and mean arterial pressure) between groups (P>0.05), but heart rate decreased in both groups, as compared to control values (P<0.05). Respiratory rate decreased (P<0.05) and expired end tidal CO2 increased progressively (P<0.05) and similarly in both groups. Anesthetic recovery period was similar between groups (P<0.05) with no adverse effects. Conclusion: Continuous administration of dexmedetomidine with calculated plasma concentration equal to 3 ng.mL-1 in combination with midazolam and ketamine provides suitable anesthesia for spay surgery in bitches, hemodynamic stability and calm awakening with no adverse effects.(AU)

Objetivo: Verificar o comportamento hemodinâmico e o índice bispectral de cadelas anestesiadas com cetamina e midazolam associados à dexmedetomidina ou medetomidina. Métodos: Vinte cadelas receberam pré-tratamento com levomepromazina e buprenorfina e foram anestesiadas com cetamina, 5 mg.kg-1 i.v., e midazolam, 0,2 mg.kg-1 i.v., seguidos da administração contínua de midazolam, 0,4 mg.kg-1.h-1, e cetamina, 20 mg.kg-1.h-1, associados, conforme o grupo, à: DEX (n=10): dexmedetomidina 20 µg.kg-1.h-1 ou MED (n=10): medetomidina 30 µg.kg-1.h-1, mantidos por 30 minutos. A dose de dexmedetomidina foi obtida por meio de estudo farmacocinético planejando-se concentração plasmática de 3,0 ng.mL-1. Resultados: Os valores do BIS diminuíram em ambos os grupos (P<0,05), mas foram menores no grupo DEX (P<0,05), em comparação com o grupo MED. Não houve diferença significativa nos atributos hemodinâmicos (frequência cardíaca, pressão arterial sistólica, diastólica e média) entre os grupos, mas a frequência cardíaca diminuiu em ambos os grupos em relação ao momento controle (P<0,05). A frequência respiratória diminuiu (P<0,05) e o CO2 expirado aumentou progressivamente em ambos os grupos (P<0,05). O tempo de recuperação anestésica foi semelhante entre os grupos (P>0,05), sem a presença de efeitos adversos. Conclusão: A administração contínua de dexmedetomidina em concentração plasmática calculada de 3 ng.mL-1, em combinação com midazolam e cetamina, resulta em plano anestésico adequado para castração de cadelas, estabilidade hemodinâmica e despertar tranquilo, sem efeitos adversos.(AU)

Índice bispectral, efeitos hemodinâmicos e respiratórios da infusão contínua de diferentes taxas de propofol em bezerros

O estudo teve por objetivo avaliar o índice bispectral, efeitos hemodinâmicos e respiratórios da infusão contínua de diferentes taxas de propofol em bezerros. Foram utilizados 8 animais de seis a 12 meses de idade, holandeses, pesando de 84 a 124 kg. Os animais foram induzidos à anestesia com propofol na dose de 5 mg/kg IV e posicionados em decúbito lateral direito, onde permaneceram respirando espontaneamente ar ambiente. Ato contínuo, a manutenção anestésica foi realizada pela infusão contínua de propofol, administrado por meio de bomba de infusão em duas diferentes taxas 0,6 mg/kg/minuto IV (G06) e 0,8 mg/kg/minuto IV, (G08) durante 60 minutos. Os 8 animais foram anestesiados duas vezes, com uma semana de intervalo entre uma anestesia e outra. As variáveis hemodinâmicas (FC, PAS, PAD, PAM, DC, PVC, PAPm, PAPOm, IC, IS, IRVS e IRVP), respiratórias (ETCO, f, SpO, 2 2 V, V, e PFI), hemogasométricas (PaO, PaCO, SaO, DB, pH e HCO -) e TE ME 2 2 2 3 índice bispectral (BIS, EMG e IQS) foram avaliadas antes da indução anestésica (M ), e 15, 30, 45 e 60 minutos após o início da infusão contínua do B propofol (M15, M30, M45 e M60, respectivamente). Já a colheita das amostras para a dosagem plasmática do propofol foi realizada aos M15, M30, M45 e M60 minutos durante a infusão contínua do propofol e as demais colheitas foram realizadas após o termino da infusão com intervalos de 10 minutos por um período de 50 minutos (M70, M80, M90, M100 e M110 respectivamente). A infusão contínua de diferentes taxas de propofol não alterou as variáveis do BIS ao longo do tempo durante a infusão, também não causou alterações hemodinâmicas importantes, porém o G08 apresentou acidose respiratória indicando uso de ventilação controlada

The aim of this study was to evaluate the bispectral index, hemodynamic and respiratory effects of continuous infusion of different rates of propofol in calves. Eight Holstein calves aging between six and 12 months and weighing 84-124 kg were used. They were induced to anesthesia with propofol at a dose of 5 mg / kg IV and positioned in right lateral recumbency, where they remained spontaneously breathing ambient air. Immediately thereafter, the anesthesia was maintained by continuous infusion of propofol administered with the aid of an infusion pump in two different rates 0.6 mg / kg / minute, IV (G06) and 0.8 mg / kg / minute, IV, (G08), during 60 minutes. The 8 animals were anesthetized twice, with one-week interval between anesthesia. The measurements of hemodynamic (HR, SAP, DAP, MAP, CO, CVP, mPAP, mPAPO, CI, SI, SVRI and PVRI), and respiratory parameters (ETCO2, f, SpO2, VTE, VME, and PFI), arterial blood gases (PaO2, PaCO2, SaO2, BE, pH and HCO3-) and bispectral index (BIS, EMG and SQI) were assessed before induction of anesthesia (MB), and 15, 30, 45 and 60 minutes after the start of continuous infusion of propofol (M15 , M30, M45 and M60, respectively). Sampling to measure plasma propofol was performed M15, M30, M45 and M60 minutes during continuous infusion of propofol and other samples were harvested after the end of infusion with 10-minute intervals during a period of 50 minutes (M70, M80, M90, M100 and M110 respectively). Continuous infusion of propofol at different rates did not alter the variables BIS over time and also did not cause significant hemodynamic changes, but the G08 had respiratory acidosis suggesting the use of controlled ventilation

Efeitos de diferentes frações inspiradas de oxigênio no índice biespectral em cães submetidos à infusão contínua de propofol / Effects of several inspired oxygen fractions on the bispectral index in dogs submitted to continuous infusion of propofol

Avaliaram-se os efeitos do fornecimento de diferentes frações inspiradas de oxigênio (FiO2) sobre o índice biespectral (BIS) em cães submetidos a infusão contínua de propofol e mantidos em ventilação espontânea. Oito cães foram submetidos a cinco anestesias, diferenciando-se uma da outra pela FiO2 fornecida. Formaram-se cinco grupos denominados G100 (FiO2 = 1); G80 (FiO2 = 0,8); G60 (FiO2 = 0,6); G40 (FiO2 = 0,4) e G20 (FiO2 = 0,21). Os animais foram induzidos à anestesia com propofol na dose necessária para intubação, e, ato contínuo, iniciaram-se a infusão do fármaco e o fornecimento de oxigênio, conforme a FiO2 determinada para cada grupo. As primeiras mensurações (M0) foram efetuadas 30 minutos após o início da infusão do anestésico e, depois, em intervalos de 15 minutos (M15, M30, M45 e M60). A pressão parcial de oxigênio no sangue arterial (PaO2) variou conforme a FiO2, ou seja, quanto maior a FiO2, maior foi a PaO2. Para a pressão parcial de dióxido de carbono no sangue arterial (PaCO2), foram registradas diferenças em M30, no qual G100 foi maior que G20. Não foram observadas diferenças significativas nas variáveis estudadas do BIS. Os intervalos de médias registrados para o BIS foram, para G100, de 68 a 62; G80, de 71 a 58; G60, de 72 a 62; G40, de 76 a 68; e G20, de 77 a 68. Conclui-se que as variáveis relacionadas ao BIS não são afetadas pelo emprego de diferentes FiO2, e sugere-se que o monitoramento pelo BIS foi capaz de detectar alterações no equilíbrio do fluxo sangüíneo cerebral, oriundas das alterações ocasionadas na dinâmica respiratória pelo emprego de diferentes frações inspiradas de oxigênio.(AU)

The effects of several inspired oxygen fractions (FiO2) on the bispectral index in spontaneously breathing dogs submitted to continuous infusion of propofol were evaluated. Eight adult mongrel dogs were used. Each animal was submitted to five anesthesias. In each procedure, the patient was allowed to breathe a different FiO2, thereby resulting in five groups, namely: G100 (FiO2 = 1), G80 (FiO2 = 0.8), G60 (FiO2 =0.6), G40 (FiO2 = 0.4), and G20 (FiO2 = 0.21). To induce anesthesia, propofol was given until the animals allowed orotracheal intubation, followed by immediate continuous infusion of drug. The initial measurement (M0) was recorded 30 minutes after the infusion of propofol onset. Additional recordings were performed at 15-minute intervals during 60 minutes (M15, M30, M45, and M60). No significant differences on BIS parameters were recorded. Regarding arterial partial pressure of carbon dioxide (PaCO2), the mean of G100 was greater than G20 at M30, whereas arterial partial pressure of oxygen (PaO2) varied according to the changes in oxygen. The mean intervals of BIS were: for G100, from 68 to 62; for G80, from 71 to 58; for G60, from 72 to 62; for G40 from 76 to 68; and for G20, from 77 to 68. In conclusion, different FiO2 does not impair BIS parameters. However, it is suggested that BIS was able to detect changes in the balance of cerebral blood flow, which was a result of changes in respiratory dynamic by the use of several inspired fractions.(AU)