Determination of the minimum alveolar concentration (MAC) of isoflurane and sevoflurane in Callithrix penicillatac

Background: The minimum alveolar concentration (MAC) is a measure of quantitative anesthetic potency and has become the standard index for the evaluation and comparison of volatile anesthetics, in addition to guiding dose administration. Black-tufted marmosets (Callithrix penicillata) are primates present in the clinical and surgical routine of veterinary hospitals, as well as experimental models, especially in neuroscience. Few studies have evaluated the potency of the main volatile anesthetics in this species. This study aimed to determine the MAC of isoflurane and sevoflurane in C. penicillata using the up-and-down method and to evaluate the effects of these drugs on the quality of anesthetic induction, maintenance, and recovery. Materials, Methods & Results: Twenty-four animals of undetermined age were used. All marmosets were healthy according to hematological and physical evaluation. The animals were randomly divided into 2 groups: ISOMAC and SEVOMAC. Each animal was induced to general anesthesia in an anesthetic box with oxygen (5 L/min) and sevoflurane at 7% in the SEVOMAC group or isoflurane at 5% in the ISOMAC. Upon reaching lateral decubitus, orotracheal intubation was performed. General anesthesia was maintained with isoflurane or sevoflurane diluted in oxygen (0.8 L/min) using a non-rebreathing delivery system under spontaneous ventilation. As defined in the pilot study, the first animal from ISOMAC started the maintenance of anesthesia with 2.6% isoflurane, while the first animal in SEVOMAC received 4% sevoflurane. After finishing the instrumentation to assess heart rate, respiratory rate, systolic blood pressure, pulse oximeter oxygen saturation, end-tidal carbon dioxide concentration, and rectal temperature, a 15-min wait to reach anesthetic equilibrium was allowed, and then an electrical noxious stimulation (50 mA and 50 Hz) was performed on the lateral aspect of the thigh (a faradic current of 3 consecutive single stimuli, followed by 2 continuous stimuli). The animals' responses to the electrical stimulus were observed. The presence of a positive response (gross movement of the limbs, head, or vocalization) or a negative response (absence of gross movements) determined the increase or reduction, respectively, of the inhalation anesthetic concentration by 10% in the subsequent marmoset. The quality of anesthetic induction and recovery from anesthesia was evaluated using a scale that measured the intensity of agitation, coughing, nausea, and vomiting. Physiological variables were recorded before (M0) and after (M1) applying the nociceptive stimulus. Isoflurane and sevoflurane MAC values in C. penicillata were 2.29 ± 0.10% and 3.93 ± 0.61 % respectively. Physiological parameters, quality of anesthetic induction and recovery did not differ significantly between groups. However, isoflurane caused irritation of the airway and ocular mucous membranes, more coughing episodes, and tearing at induction. There was no difference between groups for time to extubation and recovery time to regain sternal position. Discussion: Previous studies in primates found lower MAC values for both anesthetics, except for Lemur catta. Those findings may be explained by the use of different nociceptive stimuli and the MAC determination method employed, although no differences in MAC values have been described between bracketing or up-and-down methods in human primates and dogs. It is unlikely that the stimulus and technique alone are the determining factors for the high concentration of isoflurane and sevoflurane observed in the present study since MAC was high with both halogenates, indicating that dose extrapolation from other species can lead to the wrong anesthetic dosage.

Influence on clinical biochemistry values of black-tufted marmosets (Callithrix penicillata) anesthetized with isoflurane or sevoflurane / Influência sobre valores de bioquímica clínica de saguis-de-tufo-preto (Callithrix penicillata) anestesiados com isoflurano ou sevoflurano

The objective of this study was to evaluate the clinical biochemistry behavior of Black-Tufted Marmosets (Callithrix penicillatta) submitted to blood collection without sedation and after general anesthesia with anesthetics isoflurane or sevoflurane. Blood collections were performed on (M1) day before anesthesia by physical restraint, and (M2) after anesthesia. There were four groups: Isoflurane (GI) and Sevoflurane (GS) using an anesthetic box. GIM: isoflurane induction with mask for a shorter period. Control group (GP): physical restraint in both moments. Plasma was separated and frozen to measure clinic biochemistry values. Urea was higher at M2 in groups GI and GP. AST was higher in M2 in GI, GS, and GP and only GI showed an increase in CK in M2. Glucose was higher in M1 in the GI, GS, and GP groups and fructosamine was higher in M2 in the GI. Stress caused by physical restraint can cause biochemical changes and these must be considered when interpreting the exams. Both the inhalational anesthetic isoflurane and sevoflurane did not cause clinically significant changes in clinical biochemistry results.

O objetivo desse estudo foi avaliar o comportamento da bioquímica clínica de saguis-do-tufo-preto (Callithrix penicillatta) submetidos à coleta sanguínea sem sedação e após anestesia geral, com os anestésicos isoflurano ou sevoflurano. As coletas de sangue foram realizadas: (M1) dia antes da anestesia por contenção física e (M2) após anestesia. Foram definidos quatro grupos: isoflurano (GI) e sevoflurano (GS), utilizando caixa anestésica; GIM: indução com isoflurano com máscara por um período menor; grupo controle (GCF): contenção física em ambos os momentos. O plasma com EDTA foi separado e congelado para realizar dosagem da bioquímica clínica. A ureia foi maior no M2 nos grupos GI e GCF. A AST foi maior no M2 nos GI, GS e GCF e somente o GI apresentou aumento de CK no M2. A glicose foi maior no M1 nos grupos GI, GS e GCF, e a frutosamina foi maior no M2 no GI. O estresse causado pela contenção física pode causar alterações bioquímicas e essas devem ser levadas em consideração na interpretação dos exames. Tanto o anestésico inalatório isoflurano quanto o sevoflurano não causaram alterações clinicamente significantes nos resultados da bioquímica clínica.

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

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

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

Effects on the lipid peroxidation and the antioxidant defense systems of the use of isoflurane or sevoflurane in calves undergoing surgery

Background: Incoming anaesthesia created by the use of many drugs with different physicochemical properties is a sourceof stress and trauma for the body. This event increases the oxidative response and changes the balance between oxidant/antioxidant capacity in the organism in favor of oxidant capacity. This situation is defined as oxidative stress. For thesereasons, studies are conducted to determine the effects of general anaesthetic agents on oxidant and antioxidant systems inthe organism. In this study, it was aimed to determine the effects of isoflurane and sevoflurane used for general anaesthesiain humans and animals on lipid peroxidation and antioxidant defense system in calves.Materials, Methods & Results: The study included 14 calves of different breeds, ages, sexes, and weighing, average 2 weeksold. The cases randomly were divided into 2 groups, the isoflurane group (group I), and the sevoflurane group (group II),and each group included 7 animals. Before general anaesthesia, 0.04 mg/kg atropine was administered intramuscularly toall animals for premedication. At 15 min after atropine administration, isoflurane was administered at an inspiratory concentration of 3-5% in group I, and sevoflurane was administered at an inspiratory concentration of 5-7% in group II, via aface mask for 15 min for the induction of anaesthesia. Endotracheal intubation was performed in all cases at the 15 min ofthe induction period following the onset of general anaesthesia symptoms. After the induction, anaesthesia was continuedat an inspiratory concentration of 1.5-3% in the isoflurane group and inspiratory concentration of 2.5-4% in the sevofluranegroup. Blood samples were taken just before anaesthesia, just before skin incision, at the end of anaesthesia and surgery,and at the 24 h postoperatively. The malondialdehyde (MDA), superoxide dismutase (SOD), catalase (CAT), glutathione...

Effects on the lipid peroxidation and the antioxidant defense systems of the use of isoflurane or sevoflurane in calves undergoing surgery

Background: Incoming anaesthesia created by the use of many drugs with different physicochemical properties is a sourceof stress and trauma for the body. This event increases the oxidative response and changes the balance between oxidant/antioxidant capacity in the organism in favor of oxidant capacity. This situation is defined as oxidative stress. For thesereasons, studies are conducted to determine the effects of general anaesthetic agents on oxidant and antioxidant systems inthe organism. In this study, it was aimed to determine the effects of isoflurane and sevoflurane used for general anaesthesiain humans and animals on lipid peroxidation and antioxidant defense system in calves.Materials, Methods & Results: The study included 14 calves of different breeds, ages, sexes, and weighing, average 2 weeksold. The cases randomly were divided into 2 groups, the isoflurane group (group I), and the sevoflurane group (group II),and each group included 7 animals. Before general anaesthesia, 0.04 mg/kg atropine was administered intramuscularly toall animals for premedication. At 15 min after atropine administration, isoflurane was administered at an inspiratory concentration of 3-5% in group I, and sevoflurane was administered at an inspiratory concentration of 5-7% in group II, via aface mask for 15 min for the induction of anaesthesia. Endotracheal intubation was performed in all cases at the 15 min ofthe induction period following the onset of general anaesthesia symptoms. After the induction, anaesthesia was continuedat an inspiratory concentration of 1.5-3% in the isoflurane group and inspiratory concentration of 2.5-4% in the sevofluranegroup. Blood samples were taken just before anaesthesia, just before skin incision, at the end of anaesthesia and surgery,and at the 24 h postoperatively. The malondialdehyde (MDA), superoxide dismutase (SOD), catalase (CAT), glutathione...(AU)

Influência de diferentes doses de butorfanol na anestesia com sevofluorano em papagaios-verdadeiros (Amazona aestiva) / Influence of different doses of butorphanol in anesthesia with sevoflurane in blue-fronted parrots (Amazona aestiva)

Background: Parrots frequently require veterinary medical care. To reduce their stress, it is necessary to use chemical restraint or anesthesia. The use of balanced anesthesia techniques such as combinations of inhaled and injectable drugs is recommended. However, there is a shortage of anesthetic and analgesic protocols and data on cardiovascular and respiratory variables in wild birds. The objective of the present study was to evaluate the analgesic, cardiovascular, and respiratory effects and the quality of anesthetic recovery in blue-front parrots (Amazona aestiva) anesthetized with sevoflurane in combination with various doses of butorphanol. Materials, Methods & Results: Twenty-four clinically healthy animals, based on their clinical and hematological results (hematocrit and total plasma protein), were divided into 3 groups: 1- sevofluoran alone (GS); 2- associated with butorphanol at 3 mg/kg (GB3), and 3- 6 mg/kg (GB6) doses administered via the intramuscular (IM) route; digital clamping was used as a nociceptive stimulus. Induction and anesthetic maintenance were performed with sevoflurane at 5 and 2.5 V%, respectively, administered through a calibrated vaporizer and an anesthetic system adequate for the weight of the animals that were kept under spontaneous ventilation. It took 15 min after induction for the expired sevoflurane concentration (EtSevo) to stabilize, after which one intramuscular treatment was applied. The digital clamping was continued as a supramaximal nociceptive stimulus; if it presented a positive response, EtSevo increased by 10%, and when the stimulus decreased by 20%, digital clamping was repeated every 15 min until a positive response to the stimulus was observed. Heart rate (HR) and rhythm, respiratory rate (f), systolic blood pressure (SBP), EtSevo, expired CO2 (EtCO2 ), and body temperature (T°C) were measured during digital clamping. At the end, anesthetic...

Comparison of use of isoflurane or sevoflurane for anaesthesia induced by mask in calves

Background: Inhalation anaesthesia is an effective and reliable general anaesthesia method for inactivity, analgesia, and unconsciousness in extensive surgical procedures. Although widely used, especially in small animals, there are very few studies investigated the reliability and superiority of inhalation anaesthesia in surgical procedures for ruminants. This study intended to evaluate the anaesthetic effects of isoflurane and sevoflurane in different surgical cases with endotracheal intubation following the induction of anaesthesia using a calve-specific facemask, which is not yet a routine option in cattle. Materials, Methods & Results: The study was conducted on 14 calves, from new-born up to 3 months-old, that undergoing various surgical operations. The animals were divided into isoflurane and sevoflurane groups, and each group contained 7 animals. In all cases, atropine (0.04 mg/kg was administered intramusculer as premedication before 15 min from anaesthesia induction. For induction, the anaesthetic agent was given at an inspiratory concentration of 3-5% in the isoflurane group and at an inspiratory concentration of 5 - 7% in the sevoflurane group during 5 min via mask at 15 min after atropine administration. In both groups, endotracheal intubation was performed (about 1-3 min) after of general anaesthesia symptoms starting. At 5 min after induction, anaesthesia was continued at 1.5 - 3% in the isoflurane group and at 2.5 - 4% in the sevoflurane group during operation. The animals were monitored during anaesthesia and, anaesthetic effect, reaction of the calve, pronounced side effects, Heart Rate (HR), Systolic Arterial Blood Pressure (SABP), Diastolic Arterial Blood Pressure (DABP), Mean Arterial Blood Pressure (MABP), Respiration Rate (RR), Pulse Rate (PR), Arterial Oxygen Saturation (SpO2 ) were recorded at before anaesthesia, the premedication period, 5...

Effect of sevoflurane pretreatment in relieving liver ischemia/reperfusion-induced pulmonary and hepatic injury

Abstract Purpose To investigate the effect of sevoflurane preconditioning on ischemia/reperfusion (I/R)-induced pulmonary/hepatic injury Methods Fifty-one Wistar rats were randomly grouped into sham, I/R, and sevoflurane groups. After reperfusion, the structural change of the lung was measured by Smith score, the wet and dry weights (W/D) were determined, malondialdehyde (MDA) myeloperoxidase (MPO) content was determined colorimetrically and by fluorescence, respectively, and matrix metalloprotein-9 (MMP-9) mRNA was quantified by RT-PCR. Biopsy and morphological analyses were performed on liver tissue, activities of aspartate aminotransferase (AST) and alanine aminotransferase (ALT) were determined, and tumor necrosis factor-alpha (TNF-α) level was determined. Results The sham group showed no changes in tissue structure. Structural lesions in the sevoflurane and I/R groups were mild and severe, respectively. Smith score, W/D, MDA, MPO, and MMP mRNA showed the same trend, and were increased in the I/R group and recovered in the sevoflurane group, compared with the sham group (both P<0.05). AST and ALT were significantly increased compared to the sham group (AST: 655±52.06 vs . 29±9.30 U/L; ALT: 693±75.56 vs . 37±6.71 U/L; P<0.05). In the sevoflurane group, AST and ALT levels were significantly decreased (464±47.71 and 516±78.84 U/L; P<0.001). TNF-α presented similar results. Conclusion The protection of lung and liver by sevoflurane may be mediated by inhibited leukocyte recruitment and MMP-9 secretion.(AU)

Infusão contínua de duas doses de fentanil associadas à lidocaína e cetamina em fêmeas caninas anestesiadas com sevoflurano e submetidas à ovariohisterectomia eletiva / Continuous infusion of two doses of fentanyl associated with lidocaine and ketamine for female dogs anesthetized with sevoflurane and undergoing elective ovariohysterectomy / Infusión continua de dos dosis de fentanila asociada a lidocaína y ketamina en perras anestesiadas con sevoflurane y sometidas a ovariohisterectomía electiva

O objetivo deste trabalho foi avaliar os efeitos cardiorrespiratórios de duas doses de fentanil associadas à lidocaína e cetamina em fêmeas caninas anestesiadas com sevoflurano e submetidas à ovariohisterectomia eletiva. Foram utilizados 18 animais distribuídos aleatoriamente em dois grupos. Os animais do grupo A (GA) receberam pela via intravenosa um bolus de fentanil de 0,0018 mg/kg e os do grupo B (GB) 0,0036 mg/kg, ambos associados a lidocaína 3 mg/kg e cetamina 0,6 mg/kg. Imediatamente após o bolus realizou-se a indução com propofol seguido do início da infusão contínua (IC) de fentanil na dose de 0,0018 mg/kg/h para o GA e 0,0036 mg/kg/h para GB, ambos associados a 3 e 0,6 mg/kg/h de lidocaína e cetamina. A anestesia foi mantida com sevoflurano diluído em oxigênio 100% a 1,5V% por meio de vaporizador calibrado que foi ajustado para a manutenção do plano anestésico cirúrgico. Os animais foram posicionados em decúbito dorsal e permaneceram sob ventilação espontânea. Foram avaliados os valores basais (T0), após indução (T1) e 5 (T5), 20 (T20) e 35 (T35) minutos de IC dos seguintes parâmetros: frequência cardíaca (FC), frequência respiratória (f), pressão arterial sistólica (PAS), diastólica (PAD) e média (PAM), saturação de oxigênio na hemoglobina (SatO2), pressão parcial de dióxido de carbono (EtCO2) e o sevoflurano expirado (EtSevo). A análise estatística foi realizada através da análise de variância seguida do teste de Scott-knott. As diferenças foram consideradas significativas quando P< 0,05. A FC reduziu após 20 minutos de IC e a f, PAS, PAD e PAM diminuíram após indução anestésica. Tais diferenças não foram relevantes clinicamente e os valores se mantiveram dentro do limite fisiológico. Pode-se concluir que as duas doses de infusão contínua de fentanil produziram estabilidade cardiovascular e respiratória, além de permitirem a diminuição do requerimento de sevoflurano para a realização da ovariohisterectomia eletiva.(AU)

The aim of this study was to evaluate the cardiorespiratory effects of two doses of fentanyl associated with lidocaine and ketamine in canine females anesthetized with sevoflurane and submitted to elective ovariohysterectomy. 18 animals were randomly assigned to two groups. Group A (GA) animals received a loading dose intravenously of fentanyl 0.0018 mg/kg and those of group B (GB) 0.0036 mg/kg, both associated with lidocaine 3 mg/kg and ketamine 0, 6 mg/kg. Immediately after the loading dose, induction with propofol was realized followed by continuous infusion (CI) of fentanyl at the dose of 0.0018 mg/kg/h for GA and 0.0036 mg/kg/h for GB, both associated to 3 and 0.6 mg/kg/h of lidocaine and ketamine. The anesthesia was maintained with sevoflurane diluted in 100% oxygen at 1.5% by a calibrated vaporizer that was adjusted for the maintenance of the surgical anesthetic plane. The animals were placed in dorsal decubitus position and remained under spontaneous ventilation. Was evaluated the baseline values (T0), after induction (T1) and 5 (T5), 20 (T20) and 35 (T35) minutes of following parameters: heart rate (HR), respiratory rate (f), systolic blood pressure (SBP), diastolic blood pressure (DBP) and mean blood pressure (MAP), oxygen saturation in hemoglobin (SatO2), partial carbon dioxide (EtCO2) pressure and expired sevoflurane (EtSevo). Statistical analysis was performed through analysis of variance followed by the Scott-knott test. Differences were considered significant when P< 0.05. HR decreased after 20 minutes of CI and f, SBP, DBP and MAP decreased after anesthetic induction. These differences were not clinically relevant and the values remained within the physiological limit. It can be concluded that the two doses of continuous infusion of fentanyl produced cardiovascular and respiratory stability, besides allowing the reduction of the sevoflurane requirement for elective ovariohysterectomy.(AU)

El objetivo de este trabajo fue evaluar los efectos cardiorrespiratorios de dos dosis de fentanil asociadas a la lidocaína y cetamina en perras anestesiadas con sevoflurane y sometidas a la ovariohisterectomía electiva. Se utilizaron 18 animales distribuidos aleatoriamente en dos grupos. Los animales del grupo A (GA) recibieron por vía intravenosa un bolus de fentanil de 0,0018 mg/kg y los del grupo B (GB) 0,0036 mg/kg, ambos asociados a lidocaína 3 mg/kg y cetamina 0,6 mg/kg. Inmediatamente después del bolus se realizó la inducción con propofol seguido del inicio de la infusión continua (IC) de fentanil a la dosis de 0,0018 mg/kg/h para el GA y 0,0036 mg/kg/h para GB, ambos asociados a 3 y 0,6 mg/kg/h de lidocaína y cetamina. La anestesia fue mantenida con sevoflurane diluido en oxígeno 100% a 1,5V% a través de vaporizador calibrado que fue ajustado para el mantenimiento del plano anestésico quirúrgico. Los animales fueron colocados en decúbito dorsal y permanecieron bajo ventilación espontánea. Se evaluaron los valores basales (T0), después de la inducción (T1) y 5 (T5), 20 (T20) y 35 (T35) minutos de IC de los siguientes parámetros: frecuencia cardíaca (FC), frecuencia respiratoria (f), presión arterial sistólica (PAS), presión arterial diastólica (PAD) y presión arterial media (PAM), saturación de oxígeno en la hemoglobina (SatO2), presión parcial de dióxido de carbón (EtCO2) y el sevoflurane expirado (EtSevo). El análisis estadístico fue realizado a través del análisis de varianza seguida de la prueba de Scott-knott. Las diferencias se consideraron significativas cuando P< 0,05. La FC redujo después de 20 minutos de IC y la f, PAS, PAD y PAM disminuyeron después de la inducción anestésica. Estas diferencias no fueron relevantes clínicamente y los valores se mantuvieron dentro del límite fisiológico. Se puede concluir que las dos dosis de infusión continua de fentanil produjeron estabilidad cardiovascular y respiratoria, además de permitir la disminución del requerimiento de sevoflurane para la realización de la ovariohisterectomía electiva.(AU)

Infusão contínua de duas doses de fentanil associadas à lidocaína e cetamina em fêmeas caninas anestesiadas com sevoflurano e submetidas à ovariohisterectomia eletiva / Continuous infusion of two doses of fentanyl associated with lidocaine and ketamine for female dogs anesthetized with sevoflurane and undergoing elective ovariohysterectomy / Infusión continua de dos dosis de fentanila asociada a lidocaína y ketamina en perras anestesiadas con sevoflurane y sometidas a ovariohisterectomía electiva

O objetivo deste trabalho foi avaliar os efeitos cardiorrespiratórios de duas doses de fentanil associadas à lidocaína e cetamina em fêmeas caninas anestesiadas com sevoflurano e submetidas à ovariohisterectomia eletiva. Foram utilizados 18 animais distribuídos aleatoriamente em dois grupos. Os animais do grupo A (GA) receberam pela via intravenosa um bolus de fentanil de 0,0018 mg/kg e os do grupo B (GB) 0,0036 mg/kg, ambos associados a lidocaína 3 mg/kg e cetamina 0,6 mg/kg. Imediatamente após o bolus realizou-se a indução com propofol seguido do início da infusão contínua (IC) de fentanil na dose de 0,0018 mg/kg/h para o GA e 0,0036 mg/kg/h para GB, ambos associados a 3 e 0,6 mg/kg/h de lidocaína e cetamina. A anestesia foi mantida com sevoflurano diluído em oxigênio 100% a 1,5V% por meio de vaporizador calibrado que foi ajustado para a manutenção do plano anestésico cirúrgico. Os animais foram posicionados em decúbito dorsal e permaneceram sob ventilação espontânea. Foram avaliados os valores basais (T0), após indução (T1) e 5 (T5), 20 (T20) e 35 (T35) minutos de IC dos seguintes parâmetros: frequência cardíaca (FC), frequência respiratória (f), pressão arterial sistólica (PAS), diastólica (PAD) e média (PAM), saturação de oxigênio na hemoglobina (SatO2), pressão parcial de dióxido de carbono (EtCO2) e o sevoflurano expirado (EtSevo). A análise estatística foi realizada através da análise de variância seguida do teste de Scott-knott. As diferenças foram consideradas significativas quando P< 0,05. A FC reduziu após 20 minutos de IC e a f, PAS, PAD e PAM diminuíram após indução anestésica. Tais diferenças não foram relevantes clinicamente e os valores se mantiveram dentro do limite fisiológico. Pode-se concluir que as duas doses de infusão contínua de fentanil produziram estabilidade cardiovascular e respiratória, além de permitirem a diminuição do requerimento de sevoflurano para a realização da ovariohisterectomia eletiva.

The aim of this study was to evaluate the cardiorespiratory effects of two doses of fentanyl associated with lidocaine and ketamine in canine females anesthetized with sevoflurane and submitted to elective ovariohysterectomy. 18 animals were randomly assigned to two groups. Group A (GA) animals received a loading dose intravenously of fentanyl 0.0018 mg/kg and those of group B (GB) 0.0036 mg/kg, both associated with lidocaine 3 mg/kg and ketamine 0, 6 mg/kg. Immediately after the loading dose, induction with propofol was realized followed by continuous infusion (CI) of fentanyl at the dose of 0.0018 mg/kg/h for GA and 0.0036 mg/kg/h for GB, both associated to 3 and 0.6 mg/kg/h of lidocaine and ketamine. The anesthesia was maintained with sevoflurane diluted in 100% oxygen at 1.5% by a calibrated vaporizer that was adjusted for the maintenance of the surgical anesthetic plane. The animals were placed in dorsal decubitus position and remained under spontaneous ventilation. Was evaluated the baseline values (T0), after induction (T1) and 5 (T5), 20 (T20) and 35 (T35) minutes of following parameters: heart rate (HR), respiratory rate (f), systolic blood pressure (SBP), diastolic blood pressure (DBP) and mean blood pressure (MAP), oxygen saturation in hemoglobin (SatO2), partial carbon dioxide (EtCO2) pressure and expired sevoflurane (EtSevo). Statistical analysis was performed through analysis of variance followed by the Scott-knott test. Differences were considered significant when P< 0.05. HR decreased after 20 minutes of CI and f, SBP, DBP and MAP decreased after anesthetic induction. These differences were not clinically relevant and the values remained within the physiological limit. It can be concluded that the two doses of continuous infusion of fentanyl produced cardiovascular and respiratory stability, besides allowing the reduction of the sevoflurane requirement for elective ovariohysterectomy.

El objetivo de este trabajo fue evaluar los efectos cardiorrespiratorios de dos dosis de fentanil asociadas a la lidocaína y cetamina en perras anestesiadas con sevoflurane y sometidas a la ovariohisterectomía electiva. Se utilizaron 18 animales distribuidos aleatoriamente en dos grupos. Los animales del grupo A (GA) recibieron por vía intravenosa un bolus de fentanil de 0,0018 mg/kg y los del grupo B (GB) 0,0036 mg/kg, ambos asociados a lidocaína 3 mg/kg y cetamina 0,6 mg/kg. Inmediatamente después del bolus se realizó la inducción con propofol seguido del inicio de la infusión continua (IC) de fentanil a la dosis de 0,0018 mg/kg/h para el GA y 0,0036 mg/kg/h para GB, ambos asociados a 3 y 0,6 mg/kg/h de lidocaína y cetamina. La anestesia fue mantenida con sevoflurane diluido en oxígeno 100% a 1,5V% a través de vaporizador calibrado que fue ajustado para el mantenimiento del plano anestésico quirúrgico. Los animales fueron colocados en decúbito dorsal y permanecieron bajo ventilación espontánea. Se evaluaron los valores basales (T0), después de la inducción (T1) y 5 (T5), 20 (T20) y 35 (T35) minutos de IC de los siguientes parámetros: frecuencia cardíaca (FC), frecuencia respiratoria (f), presión arterial sistólica (PAS), presión arterial diastólica (PAD) y presión arterial media (PAM), saturación de oxígeno en la hemoglobina (SatO2), presión parcial de dióxido de carbón (EtCO2) y el sevoflurane expirado (EtSevo). El análisis estadístico fue realizado a través del análisis de varianza seguida de la prueba de Scott-knott. Las diferencias se consideraron significativas cuando P< 0,05. La FC redujo después de 20 minutos de IC y la f, PAS, PAD y PAM disminuyeron después de la inducción anestésica. Estas diferencias no fueron relevantes clínicamente y los valores se mantuvieron dentro del límite fisiológico. Se puede concluir que las dos dosis de infusión continua de fentanil produjeron estabilidad cardiovascular y respiratoria, además de permitir la disminución del requerimiento de sevoflurane para la realización de la ovariohisterectomía electiva.

Influência da lidocaína ou da dextrocetamina pela via intratesticular na anestesia com sevoflurano em cães submetidos à orquiectomia eletiva / Influence of intratesticular administration of lidocaine or dextroketamine in dogs undergoing elective orchiectomy anesthetized with sevoflurane

Background: Elective orchiectomy is one of the most performed surgeries in the veterinary practice and is considered a moderately painful procedure; thus, the use of balanced anesthesia is a good choice. Local anesthetics have shown to be effective for intratesticular and spermatic cord blocks in several species; however, there have been no reports of the use of dextroketamine with this purpose. The objective of this study was to evaluate cardiovascular and respiratory variables, and analgesia produced by intratesticular block using dextroketamine or lidocaine, as well as to assess post-anesthesia recovery and discharge in dogs subjected to elective orchiectomy under inhalation anesthesia with sevoflurane.Materials, Methods & Results: Sixteen dogs which underwent elective orchiectomy were included in this study. All animals were healthy based on clinical and hematological examinations. The animals were randomly distributed into two groups, in which 2% lidocaine at 1 mg/kg (LG) or 5% dextroketamine at 2.5 mg/kg (KG) were administered by the intratesticular route. In both groups, anesthesia was induced with propofol to effect, and maintained with 1.7 V% sevoflurane diluted in 100% oxygen, administered through a calibrated vaporizer and appropriate anesthetic system based on the animals weight, kept under spontaneous ventilation. After induction, 10 min were given for stabilization of exhaled anesthetic concentration before one of the treatments was administered intratesticularly. Five min after administration of the local block, the surgical procedure was performed, which lasted up to 15 min.[...](AU)

Influência da lidocaína ou da dextrocetamina pela via intratesticular na anestesia com sevoflurano em cães submetidos à orquiectomia eletiva / Influence of intratesticular administration of lidocaine or dextroketamine in dogs undergoing elective orchiectomy anesthetized with sevoflurane

Background: Elective orchiectomy is one of the most performed surgeries in the veterinary practice and is considered a moderately painful procedure; thus, the use of balanced anesthesia is a good choice. Local anesthetics have shown to be effective for intratesticular and spermatic cord blocks in several species; however, there have been no reports of the use of dextroketamine with this purpose. The objective of this study was to evaluate cardiovascular and respiratory variables, and analgesia produced by intratesticular block using dextroketamine or lidocaine, as well as to assess post-anesthesia recovery and discharge in dogs subjected to elective orchiectomy under inhalation anesthesia with sevoflurane.Materials, Methods & Results: Sixteen dogs which underwent elective orchiectomy were included in this study. All animals were healthy based on clinical and hematological examinations. The animals were randomly distributed into two groups, in which 2% lidocaine at 1 mg/kg (LG) or 5% dextroketamine at 2.5 mg/kg (KG) were administered by the intratesticular route. In both groups, anesthesia was induced with propofol to effect, and maintained with 1.7 V% sevoflurane diluted in 100% oxygen, administered through a calibrated vaporizer and appropriate anesthetic system based on the animal’s weight, kept under spontaneous ventilation. After induction, 10 min were given for stabilization of exhaled anesthetic concentration before one of the treatments was administered intratesticularly. Five min after administration of the local block, the surgical procedure was performed, which lasted up to 15 min.[...]

Mechanisms of the beneficial effect of sevoflurane in liver ischemia/reperfusion injury

To evaluate the underlying mechanisms by which sevoflurane protects the liver against ischemia/reperfusion injury evaluate the mechanism by which sevoflurane exerts this protective effect. METHODS: Twenty-six rats were subjected to partial ischemia/reperfusion injury for 1h: one group received no treatment, one group received sevoflurane, and sham group of animals received laparotomy only. Four hours after reperfusion, levels of alanine and aspartate aminotransferases, tumor necrosis factor-a, and interleukins 6 and 10 were measured. Analyses of mitochondrial oxidation and phosphorylation, malondialdehyde content, histology, and pulmonary vascular permeability were performed. RESULTS: Serum levels of alanine and aspartate aminotransferases were significantly lower in the sevoflurane group compared to untreated controls (p 0.05). The sevoflurane group also showed preservation of liver mitochondrial function compared to untreated controls (p 0.05). Sevoflurane administration did not alter increases in serum levels of tumor necrosis factor-a, and interleukins 6 and 10. Sevoflurane treatment significantly reduced the coagulative necrosis induced by ischemia/reperfusion (p 0.05). Pulmonary vascular permeability was preserved in the sevoflurane group compared to untreated controls. CONCLUSION: Sevoflurane administration protects the liver against ischemia/reperfusion injury, via preservation of mitochondrial function, and also preserves lung vascular permeability.(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...

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

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