RESUMO
The aim of this study was to determine the minimum anesthetic concentration of isoflurane (MACISO) and sevoflurane (MACSEVO) and evaluate the cardiorespiratory changes induced by varying fractions of inspired oxygen (FiO2) in Magellanic penguins (Spheniscus magellanicus). Twenty adult penguins (3.53 ± 0.44 kg) of undetermined sex were used. Both MACISO (n = 9) and MACSEVO (n = 13) were established using an up-and-down design. Next, twelve mechanically ventilated penguins were maintained at 1 MACISO or 1 MACSEVO (n = 6 per group) with the FiO2 initially set at 1.0. Three FiO2 values (0.6, 0.4 and 0.2) were then held constant during anesthesia for 20 minutes each. Arterial blood samples were collected for gas analysis after the 20-minute period for each FiO2. Mean ± SD MACISO was 1.93 ± 0.10% and MACSEVO was 3.53 ± 0.13%. Other than heart rate at 0.6 FiO2 (86 ± 11 beats/minute in MACISO and 132 ± 37 beats/minute in MACSEVO; p = 0.041), no significant cardiorespiratory differences were detected between groups. In both groups, decreasing the FiO2 produced increased pH values and reduced partial pressures of carbon dioxide and bicarbonate. Partial pressures of oxygen (PaO2) gradually lowered from 1.0 FiO2 through 0.2 FiO2, though hypoxemia (PaO2 < 80 mmHg) occurred only with the latter FiO2. The MACISO and the MACSEVO for the Magellanic penguin fell within the upper range of reported avian MAC estimates. To prevent hypoxemia in healthy, mechanically ventilated, either isoflurane- or sevoflurane-anesthetized Magellanic penguins, a minimum FiO2 of 0.4 should be used.
Assuntos
Anestésicos Inalatórios , Isoflurano , Oxigênio , Sevoflurano , Spheniscidae , Animais , Spheniscidae/fisiologia , Isoflurano/farmacologia , Isoflurano/administração & dosagem , Sevoflurano/farmacologia , Anestésicos Inalatórios/farmacologia , Anestésicos Inalatórios/administração & dosagem , Oxigênio/sangue , Frequência Cardíaca/efeitos dos fármacos , Masculino , Anestesia por Inalação/veterinária , Feminino , Gasometria/veterináriaRESUMO
OBJECTIVE: To determine the minimum alveolar concentration (MAC) of sevoflurane in Holstein steers using electric stimulation. STUDY DESIGN: Prospective experimental study. ANIMALS: A total of 15 Holstein steers aged 7.3 ± 1.2 months and weighing 121 ± 25 kg. METHODS: Animals were anesthetized with sevoflurane at 8% in oxygen at 5 L minute-1 via facemask and were intubated with an orotracheal tube of a compatible size. After 15 minutes of stabilization of the initial expired concentration of sevoflurane (Fe'Sevo) at 2.6%, electrical stimulation on the thoracic limb was initiated with a sequence of 2 × 10 ms followed by 2 × 3 second electrical currents of 50 V and 50 Hz, 5 seconds apart. Following each stimulus with a negative response, the Fe'Sevo was decreased by 0.2% and a 15 minute interval was awaited before the next stimulus. The procedure was repeated until the first Fe'Sevo value with a positive motor response was obtained. The Fe'Sevo was then increased by 0.1%, followed by a new stimulus, until a negative response was obtained. The value of MAC was calculated as the arithmetic mean between the lowest Fe'Sevo associated with a negative motor response and the highest Fe'Sevo associated with a positive response. RESULTS: The mean MAC for the 15 steers was 2.0 ± 0.3%, which corresponds to 2.1 ± 0.3% at sea level. CONCLUSIONS: Based on the proposed methodology, the MAC of sevoflurane for healthy Holstein steers is 2.1 ± 0.3% at sea level. CLINICAL RELEVANCE: This Fe'Sevo value can be used to guide depth of anesthesia in steers weighing approximately 120 kg in clinical practice.
Assuntos
Anestesia , Anestésicos Inalatórios , Éteres Metílicos , Animais , Sevoflurano , Estudos Prospectivos , Anestesia/veterinária , Alvéolos PulmonaresRESUMO
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.
Assuntos
Animais , Bioquímica , Callithrix , Sevoflurano , Isoflurano , AnestésicosRESUMO
Background: Mammary tumors, for which mastectomy is the main treatment, are the most common neoplasms in bitches. Mastectomy is painful and, in order to reduce the pain stimulus in the transoperative period, tumescent local anesthesia is associated with general inhalation anesthesia. However, despite the numerous benefits of tumescence, intraoperative hypothermia is the most common complication. In Medicine, especially in plastic and dermatological surgery, it is common to use a heated tumescence solution to prevent intraoperative hypothermia; however, in Veterinary medicine, no previous study has examined the advantages and disadvantages of using heated tumescence solution. Thus, this study aimed to investigate the transanesthetic cardiorespiratory effects of heated tumescence solution in bitches submitted to radical unilateral mastectomy. Materials, Methods & Results: Eight animals were treated with 0.1% lidocaine solution, warmed to 37-42°C, using a Kleins cannula for administration. Chlorpromazine (0.3 mg/kg) and meperidine (3 mg/kg) were used as pre-anesthetic medication intramuscularly, and induction was performed with intravenous propofol and maintenance with isoflurane. The data collection times were as follows: 15 min after starting isoflurane administration (M1), 5 min after tumescence (M2), after beginning of surgical incision (M3), during breast pullout (M4), after clamping of the superficial caudal epigastric vein, and artery (M5), after the beginning of the approximation of the subcutaneous tissue (M6), after the beginning of the intradermal suture (M7), and at the end of the surgical procedure (Mfinal). The heart...(AU)
Assuntos
Animais , Feminino , Cães , Mastectomia Simples/reabilitação , Mastectomia Simples/veterinária , Cuidados Pós-Operatórios/veterinária , Lidocaína/administração & dosagem , Neoplasias Mamárias Animais/cirurgia , Anestesia Local/veterinária , Anestésicos InalatóriosRESUMO
Background: Mammary tumors, for which mastectomy is the main treatment, are the most common neoplasms in bitches. Mastectomy is painful and, in order to reduce the pain stimulus in the transoperative period, tumescent local anesthesia is associated with general inhalation anesthesia. However, despite the numerous benefits of tumescence, intraoperative hypothermia is the most common complication. In Medicine, especially in plastic and dermatological surgery, it is common to use a heated tumescence solution to prevent intraoperative hypothermia; however, in Veterinary medicine, no previous study has examined the advantages and disadvantages of using heated tumescence solution. Thus, this study aimed to investigate the transanesthetic cardiorespiratory effects of heated tumescence solution in bitches submitted to radical unilateral mastectomy. Materials, Methods & Results: Eight animals were treated with 0.1% lidocaine solution, warmed to 37-42°C, using a Kleins cannula for administration. Chlorpromazine (0.3 mg/kg) and meperidine (3 mg/kg) were used as pre-anesthetic medication intramuscularly, and induction was performed with intravenous propofol and maintenance with isoflurane. The data collection times were as follows: 15 min after starting isoflurane administration (M1), 5 min after tumescence (M2), after beginning of surgical incision (M3), during breast pullout (M4), after clamping of the superficial caudal epigastric vein, and artery (M5), after the beginning of the approximation of the subcutaneous tissue (M6), after the beginning of the intradermal suture (M7), and at the end of the surgical procedure (Mfinal). The heart...
Assuntos
Feminino , Animais , Cães , Cuidados Pós-Operatórios/veterinária , Lidocaína/administração & dosagem , Mastectomia Simples/reabilitação , Mastectomia Simples/veterinária , Neoplasias Mamárias Animais/cirurgia , Anestesia Local/veterinária , Anestésicos InalatóriosRESUMO
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.
Assuntos
Animais , Feminino , Respiração Artificial/veterinária , Ovinos/fisiologia , Anestésicos Inalatórios/administração & dosagem , Sevoflurano , Procedimentos Cirúrgicos Operatórios/veterinária , Decúbito DorsalRESUMO
OBJECTIVE: To evaluate the effects of incremental doses of acepromazine on hemodynamics in isoflurane-anesthetized dogs. STUDY DESIGN: Prospective, experimental study. ANIMALS: Healthy, adult, mixed-breed dogs (two male and four female) weighing 16.8 ± 5.1 kg (mean ± standard deviation). METHODS: Dogs were anesthetized with propofol (7 mg kg-1) intravenously (IV) and isoflurane. Thermodilution and arterial catheters were placed for hemodynamic monitoring and arterial blood sampling for blood gas analysis. Baseline measurements were performed with stable expired concentration of isoflurane (Fe'Iso) at 1.8%. Each dog was then administered four incremental acepromazine injections (10, 15, 25 and 50 µg kg-1) IV, and measurements were repeated 20 minutes after each acepromazine injection with Fe'Iso decreased to 1.2%. The four acepromazine injections resulted in cumulative doses of 10, 25, 50 and 100 µg kg-1 (time points ACP10, ACP25, ACP50 and ACP100, respectively). RESULTS: Compared with baseline, cardiac index (CI) increased significantly by 34%, whereas systemic vascular resistance index (SVRI) decreased by 25% at ACP50 and ACP100. Arterial oxygen content (CaO2) was significantly lower than baseline after all acepromazine injections (maximum decreases of 11%) and was lower at ACP50 and ACP100 than at ACP10. No significant change was found in heart rate, stroke index, oxygen delivery index and systolic, mean and diastolic blood pressures. Hypotension (mean arterial pressure < 60 mmHg) was observed in one dog at baseline, ACP10, ACP25 and ACP100, and in two dogs at ACP50. CONCLUSIONS AND CLINICAL RELEVANCE: Compared with isoflurane alone, anesthesia with acepromazine-isoflurane resulted in increased CI and decreased SVRI and CaO2 values. These effects were dose-related, being more pronounced at ACP50 and ACP100. Under the conditions of this study, acepromazine administration did not change blood pressure.
Assuntos
Acepromazina , Isoflurano , Acepromazina/farmacologia , Animais , Pressão Sanguínea , Estudos Cross-Over , Cães , Feminino , Frequência Cardíaca , Hemodinâmica , Masculino , Estudos ProspectivosRESUMO
OBJECTIVES: Minimum alveolar concentration (MAC) of volatile anesthetic agents to maintain bispectral index (BIS) below 50 in 50% of patients was defined as MACBIS50. The primary objective of this study was to determine the minimum alveolar concentration of sevoflurane as a single hypnotic agent to maintain BIS below 50 in patients during normothermic cardiopulmonary bypass. DESIGN: Prospective and observational study. SETTING: Dante Pazzanese Institute of Cardiology, Brazil. PARTICIPANTS: Eighteen consecutive patients scheduled for elective coronary artery bypass grafting (CABG) with cardiopulmonary bypass (CPB) under general anesthesia, American Society of Anesthesiologists physical status classes III and IV, between the ages of 40 and 70, were included in the study. METHODS: All patients underwent inhalation induction with facial mask using sevoflurane (Cristália) in 100% oxygen, pancuronium (Cristália) 0.1 mg/kg, and sufentanil (Cristália) 0.5 µg/kg intravenously (IV) administered. A single bolus dose of sufentanil, 1.0 µg/kg IV, was administered before surgical incision. MACBIS50 was calculated using the midpoint concentration of patients involving a crossover (BIS < or ≥50) according to Dixon's Up-and-Down method. The Up-and-Down sequence also was analyzed by probit test that enabled the authors to obtain the effective dose 50 (ED50) and effective dose 95 (ED95) of sevoflurane to maintain a BIS value <50, with a 95% confidence interval (95% CI) of the mean. RESULTS: A total of 15 patients were analyzed in this study. MACBIS50 of sevoflurane as a single hypnotic agent was 0.82% (95% CI 0.47-1.16) in patients aged 40 to 70 undergoing CABG during normothermic CPB. The ED50 and ED95 of sevoflurane to maintain a BIS value <50 for the same context were 0.73% (95% CI 0.45-1.00) and 1.39 (95% CI 0.42-2.37) by means of probit analysis, respectively. CONCLUSION: MACBIS50 of sevoflurane as a single hypnotic agent was 0.82% in patients undergoing CABG during normothermic CPB.
Assuntos
Anestésicos Inalatórios , Éteres Metílicos , Adulto , Idoso , Brasil , Ponte Cardiopulmonar , Humanos , Hipnóticos e Sedativos , Pessoa de Meia-Idade , Estudos Prospectivos , SevofluranoRESUMO
BACKGROUND AND OBJECTIVES: This clinical trial aimed to evaluate the effects of two different inhalation anesthetic agents on postoperative olfactory memory and olfactory function in patients who underwent micro laryngeal surgery. METHODS: This randomized prospective controlled study consisted of 102 consecutive patients with a voice disorder. The patients underwent micro laryngeal surgery for voice disorders under general anesthesia. Patients who did not meet inclusion criteria and/or declined to participate (n=34) were excluded from the study. Patients were divided into two groups. Four patients from Group 1 and four patients from Group 2 were lost to follow-up. Group 1 (n=30) received sevoflurane, and Group 2 (n=30) received desflurane during anesthesia. We compared the results by performing the pre-op and post-op Connecticut Chemosensory Clinical Research Center Olfactory test. RESULTS: Thirty-three patients (55%) were male and 27 (45%) were female. The mean age was 48.18±13.88 years (range: 19-70 years). Preoperative and postoperative olfactory functions did not show a significant difference within the groups postoperatively (p> 0.05). Preoperative and postoperative olfactory memory showed a significant decrease 3hours after the surgery (p <0.05). CONCLUSIONS: Olfactory functions and memory were not affected by desflurane in the early postoperative period. Although sevoflurane did not affect olfactory functions, it had a temporary negative effect on olfactory memory in the early postoperative period.
Assuntos
Anestésicos Inalatórios/farmacologia , Desflurano/farmacologia , Memória de Curto Prazo/efeitos dos fármacos , Memória de Curto Prazo/fisiologia , Sevoflurano/farmacologia , Olfato/efeitos dos fármacos , Olfato/fisiologia , Adulto , Idoso , Feminino , Humanos , Laringe/cirurgia , Masculino , Pessoa de Meia-Idade , Período Pós-Operatório , Estudos Prospectivos , Adulto JovemRESUMO
Abstract Background and objectives: This clinical trial aimed to evaluate the effects of two different inhalation anesthetic agents on postoperative olfactory memory and olfactory function in patients who underwent micro laryngeal surgery. Methods: This randomized prospective controlled study consisted of 102 consecutive patients with a voice disorder. The patients underwent micro laryngeal surgery for voice disorders under general anesthesia. Patients who did not meet inclusion criteria and/or declined to participate (n = 34) were excluded from the study. Patients were divided into two groups. Four patients from Group 1 and four patients from Group 2 were lost to follow-up. Group 1 (n = 30) received sevoflurane, and Group 2 (n = 30) received desflurane during anesthesia. We compared the results by performing the pre-op and post-op Connecticut Chemosensory Clinical Research Center Olfactory test. Results: Thirty-three patients (55%) were male and 27 (45%) were female. The mean age was 48.18 ± 13.88 years (range: 19‒70 years). Preoperative and postoperative olfactory functions did not show a significant difference within the groups postoperatively (p > 0.05). Preoperative and postoperative olfactory memory showed a significant decrease 3 hours after the surgery (p < 0.05). Conclusions: Olfactory functions and memory were not affected by desflurane in the early postoperative period. Although sevoflurane did not affect olfactory functions, it had a temporary negative effect on olfactory memory in the early postoperative period.
Resumo Introdução e objetivos: O estudo avaliou o efeito pós-operatório de dois agentes anestésicos inalatórios distintos na memória olfativa de curta duração e na função olfativa em pacientes submetidos à microcirurgia de laringe. Método: O estudo prospectivo controlado randomizado avaliou, consecutivamente, 102 pacientes com alteração vocal submetidos à microcirurgia de laringe sob anestesia geral. Trinta e quatro pacientes não obedeceram aos critérios de inclusão e/ou não aceitaram participar do estudo e foram excluídos. Os pacientes foram divididos em dois grupos. Quatro pacientes do Grupo 1 e quatro do Grupo 2 foram perdidos durante o seguimento. O Grupo 1 (n = 30) recebeu sevoflurano durante a anestesia e o Grupo 2 (n = 30), desflurano. Comparamos resultados pré e pós-operatórios de memória olfativa e funções olfativas, realizando o Connecticut Chemosensory Clinical Research Center Olfactory test. Resultados: Foram incluídos um total de 33 (55%) homens e 27 (45%) mulheres. A idade média foi 48,18 ± 13,88 anos (variação: 19-70 anos). As funções olfativas pré e pós-operatórias não apresentaram diferença estatisticamente significante dentro dos grupos no pós-operatório (p > 0,05). A memória olfativa pré e pós-operatória não mostrou diminuição estatisticamente significante quando avaliada três horas após a cirurgia (p< 0,05). Conclusões: Memória e funções olfativas não foram alteradas pelo desflurano no pós-operatório imediato. Embora o sevoflurano não tenha alterado as funções olfativas, causou efeito temporário negativo na memória olfativa no pós-operatório imediato.