RESUMO: 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.

ABSTRACT: 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.

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.

PURPOSE: To assess the cardiorespiratory parametes, recovery, gastrointestinal motility and serum cortisol concentrations in horses anesthetized with isoflurane with or without a continuous rate infusion (CRI) of butorphanol for orchiectomy. METHODS: Twelve adult, intact, male horses weighing 332 ± 55 kg were included in the study. Xilazine was administered as premedication. Anesthesia was induced with ketamine and midazolam and maintained with isoflurane. Butorphanol (0.025 mg kg-1 bolus) or an equivalent volume of saline (0.9%) was given intravenously followed by a CRI of butorphanol (BG) (13 µg kg-1 hour-1) or saline (CG). Cardiorespiratory variables were recorded before (T0) and every 15 minutes for 75 minutes after the start of infusion. Serum cortisol concentration was measured at T0 and 60 minutes, and 30 minutes and 19 hours after the horse stood up. Recovery from anesthesia was evaluated using a scoring system. Gastrointestinal motility was evaluated before anesthesia and during 24 hours after recovery. RESULTS: There were no significant differences between groups in cardiopulmonary variables, or recovery scores or serum cortisol concentrations. A reduction in gastrointestinal motility was recorded for 60 minutes in BG. CONCLUSIONS: Continuous rate infusion of butorphanol in horses anesthetized with isoflurane did not adversely affect the cardiopulmonary variables monitored, or recovery scores. A small but statistically significant reduction in gastrointestinal motility occurred in the butorphanol group.

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.

Com este estudo objetivou-se avaliar, comparativamente, os efeitos de três anestésicos inalatórios sobre variáveis respiratórias e hemogasométricas em cães. Para tal, utilizaram-se 30 cães sadios, adultos, machos e fêmeas evitando-se aquelas em estro ou em gestação. Os animais foram separados e protocolados em três grupos de 10 cães cada (G1, G2 e G3). Induziu-se a anestesia geral com administração intravenosa de propofol, na dose de 10±1,3 mg/kg. Em seguida procedeu-se à intubação orotraqueal e anestesia geral inalatória pelo desfluorano (G1), sevofluorano (G2) e isofluorano (G3), diluídos em oxigênio a 100,00%, por meio de circuito anestésico tipo "semi-fechado", dotado de vaporizadores calibrados para cada agente anestésico. As variáveis estudadas foram Freqüência Respiratória, CO2 ao Final da Expiração, Saturação de Oxihemoglobina, Volume Corrente, Volume Minuto, Pressão Parcial Arterial de O2, Pressão Parcial Arterial de CO2, Excesso de Bases e pH. A avaliação estatística destas variáveis foi realizada pela Análise de Perfil, sendo considerado o nível de significância de 5,00%. Os resultados obtidos permitiram concluir que o desfluorano deprime o sistema respiratório aumentando a pressão parcial arterial de CO2 e o CO2 ao final da expiração; e diminuindo a pressão parcial arterial de O2 e o volume minuto, quando comparado com os outros anestésicos em teste.

The aim of this work was to evaluate, comparatively, the effects of three volatile anesthetics upon respiratory and haemogasometric variables in dogs. For such, 30 adult, male and female healthy mongrel dogs were used. The animals were separated in 3 groups of 10 dogs each (G1, G2 and G3). General anesthesia was induced with intravenous administration of propofol (10±1,3 mg/kg). The dogs were submitted to inhalatory anesthesia with desflurane (G1), sevoflurane (G2) and isoflurane (G3), diluted in oxygen at 100,00%, through a semi-closed type anesthetic circuit. The following variables were studied: Respiratory Rate, End Tidal CO2, Pulse Oximetry, Tidal Volume, Minute Volume, Arterial O2, Arterial CO2, Bases Excess and pH. The statistical evaluation was accomplished by Profile Analisys (p<0,05). The results allowed us to conclude that desflurane depresses the respiratory system increasing the arterial CO2 and the End tidal CO2; and decreasing arterial O2 and minute volume, when compared with the other anesthetics in test.