Effects of Dexmedetomidine Infusion During Sevoflurane Anesthesia on Otoacoustic Emissions

BACKGROUND AND OBJECTIVES: Knowing the ototoxic potential of the agents used in medical treatments is important for the protection of hearing. Although we have knowledge regarding some effects of dexmedetomidine, which is an anesthetic-sparing drug, its influence over the hearing system has never been studied and is obscure yet. The aim of this study is to determine the effects of intravenous dexmedetomidine application during sevoflurane anesthesia on otoacoustic emissions (OAEs). SUBJECTS AND METHODS: This prospective randomized study was performed on 60 patients (34 male, 26 female, mean age: 30.6±9.2 years) who were scheduled for an elective surgery under general anesthesia and the patients were enrolled and randomly divided into 2 groups. They received dexmedetomidine (Group D) or Saline (Group S) infusion during a standardized Sevoflurane anesthesia. Transient and distortion product OAEs were measured preoperatively and postoperatively (24th hour). OAE results were compared within and between groups. RESULTS: In group D postoperative OAEs were lower than preoperative OAEs and postoperative levels of group S, especially at low frequencies (p<0.05). CONCLUSIONS: Dexmedetomidine infusion affects the micromechanical function of cochlea especially in the low-frequency region. Dexmedetomidine should be carefully used during general anesthesia to avoid its probable harmful effects on cochlear micromechanics.

Minimum alveolar concentration of isoflurane in dogs administered two morphine doses / Concentração alveolar mínima do isoflurano em cães tratados com duas doses de morfina

ABSTRACT: This study aimed to evaluate the effects of intramuscular 0.5mg kg-1 (MOR0.5) and 1.0mg kg-1 (MOR1.0) morphine premedication on the minimum alveolar concentration of isoflurane (ISOMAC) in dogs. Eighteen client-owned female dogs were scheduled for elective ovariohysterectomy. Dogs received intramuscular MOR0.5 or MOR1.0 as premedication and propofol IV for induction of anesthesia. Isoflurane was delivered for maintenance of anesthesia and dogs were maintained under normocapnia and normothermia. Determinations of the ISOMAC were conducted by use of the "up-and-down" method. Noxious stimulus (placement of Backhaus towel clamps, a midline skin incision and subcutaneous tissue dissection) was delivered approximately 50 minutes after premedication with MOR0.5 or MOR1.0. The calculated ISOMAC was 0.98±0.15% in MOR0.5 and 0.80±0.08% in MOR1.0. The ISOMAC was significantly lower in MOR1.0 compared with MOR0.5 (P=0.010). Results of this study suggested that intramuscular premedication with morphine 0.5 and 1.0mg kg-1 decreases the ISOMAC in a dose-related manner in dogs.

RESUMO: O presente estudo objetivou avaliar os efeitos da administração intramuscular de 0,5mg kg-1 (MOR0,5) ou 1,0mg kg-1 (MOR1,0) de morfina sobre a concentração alveolar mínima do isoflurano (CAMISO) em cães. Dezoito cadelas de proprietários foram agendadas para ovário-histerectomia eletiva. As cadelas receberam MOR0,5 ou MOR1,0, como medicação pré-anestésica, e propofol IV para indução da anestesia. A manutenção da anestesia foi realizada com isoflurano em condições de normocapnia a normotermia. A determinação da CAMISO foi conduzida de acordo com o método "up-and-down". O estímulo nociceptivo (colocação de pinças Backhaus, incisão da pele na linha média e dissecção de tecido subcutâneo) foi realizado aproximadamente 50 minutos após a administração de MOR0,5 ou MOR1,0. A CAMISO calculada foi 0,98±0,15% em MOR0,5 e 0,80±0,08% em MOR1,0. A CAMISO foi significativamente menor em MOR1,0 do que em MOR0,5 (P=0,010). Os resultados do estudo sugerem que a medicação pré-anestésica com morfina nas doses de 0,5 e 1,0mg kg-1, pela via intramuscular, resulta em redução dose-dependente na CAMISO em cães.

Effect of dexmedetomidine in children undergoing general anesthesia with sevoflurane: a meta-analysis / Efeito da dexmedetomidina em crianças submetidas à anestesia geral com sevoflurano

Abstract Background and objectives: Sevoflurane is often used in pediatric anesthesia and is associated with high incidence of psychomotor agitation. In such cases, dexmedetomidine (DEX) has been used, but its benefit and implications remain uncertain. We assessed the effects of DEX on agitation in children undergoing general anesthesia with sevoflurane. Method: Meta-analysis of randomized clinical and double-blind studies, with children undergoing elective procedures under general anesthesia with sevoflurane, using DEX or placebo. We sought articles in English in PubMed database using the following terms: Dexmedetomidine, sevoflurane (Methyl Ethers/sevoflurante), and agitation (Psychomotor Agitation). Duplicate articles with children who received premedication and used active control were excluded. It was adopted random effects model with DerSimonian-Laird testing and odds ratio (OR) calculation for dichotomous variables, and standardized mean difference for continuous variables, with their respective 95% confidence interval (CI). Results: Of 146 studies identified, 10 were selected totaling 558 patients (282 in DEX group and 276 controls). The use of DEX was considered a protective factor for psychomotor agitation (OR = 0.17; 95% CI 0.13-0.23; p < 0.0001) and nausea and vomiting in PACU (OR = 0.49; 95% CI 0.35-0.68; p < 0.0001). Wake-up time and PACU discharge time were higher in the dexmedetomidine group. There was no difference between groups for extubation time and duration of anesthesia. Conclusion: Dexmedetomidine reduces psychomotor agitation during wake-up time of children undergoing general anesthesia with sevoflurane.

Resumo Justificativa e objetivos: Sevoflurano é frequentemente usado em anestesia pediátrica e está associado à alta incidência de agitação psicomotora ao despertar. Nesses casos a dexmedetomidina (dex) tem sido usada, porém permanecem incertos seus benefícios e suas implicações. Foram avaliados os efeitos da dex sobre a agitação no despertar de crianças submetidas à anestesia geral com sevoflurano. Método: Metanálise de ensaios clínicos randomizados e duplamente encobertos, com crianças submetidas a procedimentos eletivos sob anestesia geral com sevoflurano, que usaram dex ou placebo. Buscaram-se artigos em língua inglesa na base de dados Pubmed com termos como Dexmedetomidine, sevoflurane (Methyl Ethers/sevoflurane) e agitation (Psychomotor Agitation). Artigos duplicados, com crianças que receberam medicação pré-anestésica e que usaram controle ativo foram excluídos. Adotou-se modelo de efeitos aleatórios com testes de DerSimonian-Laird e cálculo de odds ratio (OR) para variáveis dicotômicas e diferença de média padronizada para variáveis contínuas, com seus respectivos intervalos de confiança de 95% (IC). Resultados: Dos 146 estudos identificados, 10 foram selecionados, com 558 pacientes (282 no grupo dex e 276 controles). O uso da dex foi considerado fator de proteção para agitação psicomotora (OR = 0,17; 95% IC 0,13-0,23; p < 0,0001) e para náuseas e vômitos na SRPA (OR = 0,49; 95% IC 0,35-0,68; p < 0,0001). Tempo para despertar e para alta da SRPA foram maiores no grupo dexmedetomidina. Não houve diferença entre os grupos para tempo de extubação e duração da anestesia. Conclusão: A dexmedetomidina reduz a agitação psicomotora no despertar de crianças submetidas à anestesia geral com sevoflurano.

Randomized, controlled trial comparing the effects of anesthesia with propofol, isoflurane, desflurane and sevoflurane on pain after laparoscopic cholecystectomy / Estudo randômico controlado que compara os efeitos da anestesia com propofol, isoflurano, desflurano e sevoflurano sobre a dor pós-colecistectomia videolaparoscópica / Estudio aleatorizado controlado comparando los efectos de la anestesia con propofol, isoflurano, desflurano y sevoflurano sobre el dolor poscolecistectomía videolaparoscópica

Background: Pain is the primary complaint and the main reason for prolonged recovery after laparoscopic cholecystectomy. The authors hypothesized that patients undergoing laparoscopic cholecystectomy will have less pain four hours after surgery when receiving maintenance of anesthesia with propofol when compared to isoflurane, desflurane, or sevoflurane. Methods: In this prospective, randomized trial, 80 patients scheduled for laparoscopic cholecystectomy were assigned to propofol, isoflurane, desflurane, or sevoflurane for the maintenance of anesthesia. Our primary outcome was pain measured on the numeric analog scale four hours after surgery. We also recorded intraoperative use of opioids as well as analgesic consumption during the first 24 h after surgery. Results: There was no statistically significant difference in pain scores four hours after surgery (p = 0.72). There were also no statistically significant differences in pain scores between treatment groups during the 24 h after surgery (p = 0.45). Intraoperative use of fentanyl and morphine did not vary significantly among the groups (p = 0.21 and 0.24, respectively). There were no differences in total morphine and hydrocodone/APAP use during the first 24 h (p = 0.61 and 0.53, respectively). Conclusion: Patients receiving maintenance of general anesthesia with propofol do not have less pain after laparoscopic cholecystectomy when compared to isoflurane, desflurane, or sevoflurane. .

Justificativa e objetivo: a dor é a principal queixa e também o motivo principal de recuperação prolongada pós-colecistectomia laparoscópica. A nossa hipótese foi que os pacientes submetidos à colecistectomia laparoscópica apresentariam menos dor quatro horas após a cirurgia se recebessem manutenção anestésica com propofol em comparação com isoflurano, desflurano ou sevoflurano. Métodos: neste estudo prospectivo e randômico, 80 pacientes agendados para colecistectomia laparoscópica foram designados para receber propofol, isoflurano, desflurano ou sevoflurano para manutenção da anestesia. Nosso desfecho primário foi dor mensurada em escala analógica numérica quatro horas após a cirurgia. Também registramos o uso intraoperatório de opiáceos, bem como o consumo de analgésicos durante as primeiras 24 horas pós-cirúrgicas. Resultados: não houve diferença estatisticamente significante nos escores de dor quatro horas após a cirurgia (p = 0,72). Também não houve diferença estatisticamente significativa nos escores de dor entre os grupos de tratamento durante as 24 horas pós-cirúrgicas (p = 0,45). O uso intraoperatório de fentanil e morfina não variou significativamente entre os grupos (p = 0,21 e 0,24, respectivamente). Não houve diferença no consumo total de morfina e hidrocodona/APAP durante as primeiras 24 horas (p = 0,61 e 0,53, respectivamente). Conclusão: os pacientes que receberam propofol para manutenção da anestesia geral não apresentaram menos dor pós-colecistectomia videolaparoscópica em comparação com os que receberam isoflurano, desflurano ou sevoflurano. .

Justificación y objetivo: el dolor es el principal motivo de queja y también la principal razón de una prolongada recuperación tras una colecistectomía laparoscópica. Nuestra hipótesis fue que los pacientes sometidos a colecistectomía laparoscópica tenían menos dolor 4 h después de la cirugía cuando recibían propofol para la anestesia en comparación con isoflurano, desflurano o sevoflurano. Métodos: en este estudio prospectivo y aleatorizado, 80 pacientes programados para colecistectomía laparoscópica fueron designados para recibir propofol, isoflurano, desflurano o sevoflurano para el mantenimiento de la anestesia. Nuestro primer resultado fue el dolor medido en escala analógica numérica 4 h después de la cirugía. También registramos el uso intraoperatorio de opiáceos y el consumo de analgésicos durante las primeras 24 h del postoperatorio. Resultados: no hubo diferencias estadísticamente significativas en las puntuaciones del dolor 4 h después de la cirugía (p = 0,72). Tampoco hubo diferencias estadísticamente significativas en las puntuaciones del dolor entre los grupos de tratamiento durante las 24 h del postoperatorio (p = 0,45). El uso intraoperatorio de fentanilo y morfina no varió significativamente entre los grupos (p = 0,21 y 0,24 respectivamente). No hubo una diferencia en el consumo total de morfina e hidrocodona/APAP durante las primeras 24 h (p = 0,61 y 0,53 respectivamente). Conclusiones: los pacientes que recibieron propofol para el mantenimiento de la anestesia general no tenían menos dolor poscolecistectomía videolaparoscópica en comparación con los que recibieron isoflurano, desflurano o sevoflurano. .

O efeito dos anestésicos inalatórios halotano e sevoflurano em um modelo experimental de lesão hepática / Effects of the inhalational anesthetics halothane and sevoflurane on an experimental model of hepatic injury

JUSTIFICATIVA E OBJETIVOS: A lesão hepática pós-anestesia inalatória ainda é controversa. Estudos sugerem que agentes inalatórios geram uma resposta imune que pode provocar lesões hepáticas. O objetivo deste estudo é analisar o efeito dos anestésicos inalatórios halotano e sevoflurano no fígado de ratos submetidos à hipóxia e à reperfusão. MÉTODO: Foram utilizados 30 ratos Wistar pré-tratados com fenobarbital 0,1 por cento por cinco dias, com suspensão da medicação 24 horas antes do experimento, a fim de provocar a lesão hepática. Os animais foram distribuídos em cinco grupos com seis ratos cada. O Grupo C foi o de controle, sem qualquer tipo de tratamento; o Grupo F foi aquele no qual se induziu lesão hepática com fenobarbital; o Grupo Hipóxia foi exposto a 14 por cento de oxigênio (O2); o Grupo H recebeu halotano 1 por cento e 14 por cento de O2; e o Grupo S recebeu sevoflurano 2 por cento e 14 por cento de O2. Contadas 24 horas após a exposição dos gases, realizaram-se coletas de sangue para avaliação de transaminases (AST e ALT) e de amostras de fígado para avaliação histológica. Foram usados os testes de Análise de Variância não paramétrica de Kruskal-Wallis e, para comparação de médias, os testes de Newman-Keuls. RESULTADOS: A atividade enzimática revelou que os valores de média amostral de AST (280,33 para halotano, 181 para sevoflurano) e ALT (235 para halotano e 48,33 para sevoflurano) não indicaram diferença estatística significativa; os grupos testados apresentaram valores elevados. O sevoflurano, quando comparado com o halotano à microscopia óptica, apresentou índices menores de alteração morfológica, com p = 0,045 para esteatose, p = 0,0075 para infiltrado inflamatório e p = 0,0074 para necrose. CONCLUSÕES: O Grupo sevoflurano, quando comparado ao Grupo halotano, não apresentou lesão no parênquima hepático quando avaliado por microscopia óptica.

BACKGROUND AND OBJECTIVES: Hepatic injury after inhalational anesthesia is controversial. Studies have suggested that inhalational agents generate an immune response that can provoke hepatic injury. The objective of this study was to analyze the effects of the inhalational agents halothane and sevoflurane on the liver of rats submitted to hypoxia and reperfusion. METHODS: Thirty Wistar rats, pretreated with 0.1 percent phenobarbital for 5 days, with discontinuation of the drug 24 hours before the experiment to cause hepatic injury, were used. Animals were distributed in five groups of six rats each. The control group (C) did not receive any treatment; in the F group, phenobarbital was used to induce hepatic injury; the Hypoxia group was submitted to 14 percent oxygen (O2); the H group received 1 percent halothane and 14 percent O2; and the S group received 2 percent sevoflurane and 14 percent O2. Twenty-four hours after exposure to the gases, blood samples were collected to evaluate transaminases (AST and ALT), and liver samples were collected for histological evaluation. Kruskal-Wallis Analysis of Variance and the Newman-Keuls test were used. RESULTS: Enzymatic activity mean values of AST (280.33, for halothane, 181, for sevoflurane) and ALT (235 for halothane, and 48.33, for sevoflurane) did not show significant differences, and all groups showed elevated values. Compared to halothane on optical microscopy, sevoflurane had lower indices of morphologic changes with p = 0.045, for steatosis, p = 0.0075, for inflammatory infiltrate, and p = 0.0074, for necrosis. CONCLUSIONS: Compared to the halothane group, sevoflurane did not show injuries of the liver parenchyma on optical microscopy.

JUSTIFICATIVA Y OBJETIVOS: La lesión hepática postanestesia inhalatoria todavía es algo controversial. Algunos estudios sugieren que los agentes inhalatorios generan una respuesta inmune que puede provocar lesiones hepáticas. El objetivo de este estudio fue analizar el efecto de los anestésicos inhalatorios halotano y sevoflurano en el hígado de ratones que fueron sometidos a la hipoxia y a la reperfusión. MÉTODO: Fueron utilizados 30 ratones Wistar tratados previamente con fenobarbital al 0,1 por ciento durante cinco días, con suspensión de la medicación 24 horas antes del experimento para provocar la lesión hepática. Los animales fueron distribuidos en cinco grupos con seis ratones cada uno. El grupo C fue el de control, sin ningún tipo de tratamiento; el grupo F fue aquel en el cual se indujo la lesión hepática con fenobarbital; el grupo Hipoxia se expuso a un 14 por ciento de oxígeno (O2); el grupo H recibió halotano al 1 por ciento y al 14 por ciento de O2; y el grupo S recibió sevoflurano al 2 por ciento y al 14 por ciento de O2. Contadas 24 horas después de la exposición de los gases, se realizó la recolección de sangre para la evaluación de las transaminasas (AST y ALT), y de las muestras de hígado para la evaluación histológica. Fueron usados los test de Análisis de Variancia no paramétrica de Kruskal-Wallis, y para la comparación de los promedios se usaron los test de Newman-Keuls. RESULTADOS: La actividad enzimática arrojó valores de promedio de muestra de AST (280,33 para halotano, 181 para sevoflurano y ALT 235 para halotano y 48,33 para sevoflurano), que no indicaron diferencia estadística significativa: los grupos testados presentaron valores elevados. El sevoflurano, cuando fue comparado con el halotano a la microscopía óptica, presentó índices menores de alteración morfológica, con p = 0,045 para esteatosis, p = 0,0075 para infiltrado inflamatorio y p = 0,0074 para necrosis. CONCLUSIONES: El grupo sevoflurano, cuando se comparó con el grupo h...

Effect of Inhalational Anesthetics on Cytotoxicity and Intracellular Calcium Differently in Rat Pheochromocytoma Cells (PC12) / 华中科技大学学报（医学）（英德文版）

Isoflurane, a commonly used inhaled anesthetic, induces apoptosis in rat pheochromo-cytoma cells (PC12) in a concentration- and time-dependent manner with unknown mechanism. We hypothesized that isoflurane induced apoptosis by causing abnormal calcium release from the endo-plasmic reticulum (ER) via activation of inositol 1,4,5-trisphosphate (IP3) receptors. Alzheimer's pre-senilin-1 (PS1) mutation increased activity of IP3 receptors and therefore rendered cells vulnerable to isoflurane-induced cytotoxicity. Sevoflurane and desflurane had less ability to disrupt intraceUular calcium homeostasis and thus being less potent to cause cytotoxicity. This study examined and com- pared the cytotoxic effects of various inhaled anesthetics on PC12 cells transfected with the Alz- heimer's mutated Psi (L286V) and the disruption of intracellular calcium homeostasis. PC12 cells transfected with wild type (WT) and mutated PS1 (L286V) were treated with equivalent of 1 MAC of isoflurane, sevoflurane and desflurane for 12 h. MTT reduction and LDH release assays were per- formed to evaluate cell viability. Changes of calcium concentration in cytosolic space ([Ca2+]c) were determined after exposing different types of cells to various inhalational anesthetics. The effects of IP3 receptor antagonist xestospongin C on isoflurane-induced cytotoxicity and calcium release from the ER in L286V PC12 cells were also determined. The results showed that isoflurane at 1 MAC for 12 h induced cytoxicity in L286V but not WT PC12 cells, which was also associated with greater and faster elevation of peak [Ca2+]c in L286V than in the WT cells. Xestospongin C significantly amelio- rated isoflurane cytotoxicity in L286V cells, as well as inhibited the calcium release from the ER in L286V cells. Sevoflurane and desflurane at equivalent exposure to isoflurane did not induce similar cytotoxicity or elevation of peak [Ca2+]c in L286V PC12 cells. These results suggested that isoflurane induced cytoxicity by partially causing abnormal calcium release from the ER via activation of IP3 receptors in L286V PC12 cells. Sevoflurane and desflurane at equivalent exposure to isoflumne did not induce similar elevation of [Ca2+]c or neurotoxicity in PC12 cells transfected with the Alzheimer's PS1 mutation.

The Combined Effect of Desflurane and Milrinone on the Function of the Isolated Rat Heart / 대한마취과학회지

BACKGROUND: Desflurane depresses the contractile function of the myocardium. It also causes direct coronary vasodilation. Milrinone, a phosphodiesterase III inhibitor, usually increases myocardial contractility and also has vasodilatory activity. Some inhalation anesthetic agents, such as isoflurane, are safely combined with phosphodiesterase III inhibitors clinically, but milrinone sometimes causes significant hypotension by reducing systemic vascular resistance. The purpose of this study was to evaluate the effect of the combined use of desflurane and milrinone on the function of the isolated rat heart. METHOD: Thirty isolated rat hearts were divided into two groups. [Group 1 (n = 15): desflurane, Group 2 (n = 15): desflurane and milrinone] They were perfused continuously with modified Krebs' solution in a Langendorff retrograde perfusion apparatus. After measuring the control values of the hemodynamic and oxygenation parameters in each group, we administered 6.6 vol% of desflurane to both groups and added sequential perfusion of modified Krebs' solution containing 0.5, 1.0, and 1.5mug/ml of milrinone in Group 2 and then measured the parameters and analyzed them statistically. RESULTS: Baseline measurements in both groups were not statistically different. In Group 1, desflurane significantly decreased LVP (55+/-5 mmHg), dp/dt (557+/-65 mmHg/sec) and MVO2 (71.2+/-16.3 ml/g/min) after 15 minutes. CF (13.9+/-3.1 ml/g/min) and DO2 (176.7+/-43.4 ml/g/min) were increased after 15 minutes. There was no further change after this. In Group 2, desflurane decreased LVP (53+/-18 mmHg), dp/dt (558 90 mmHg/sec) and MVO2 (72.0+/-11.0 ml/g/min) and increased CF (14.2+/-1.9 ml/g/min) and DO2 (175.3+/-29.1 ml/g/min). But, there was no significant difference in the effects of desflurane between the two groups. Milrinone restored LVP, dp/dt and MVO2 to the baseline level, but not with dose-dependency. Desflurane-induced elevated CF and DO2 did not show further changes. CONCLUSIONS: These findings suggest that milrinone increased myocardial contractility and restored the desflurane-induced myocardial depression of the isolated rat heart without further increase of oxygen consumption from the baseline control value. In addition, no additive effects was observed on coronary blood flow when these two agents were used in combination.

The Comparison of Characteristics in Emergence between Inhalational Anesthesia Using Isoflurane and Total Intravenous Anesthesia Using Propofol and Ketamine / 대한마취과학회지

BACKGROUND: Total intravenous anesthesia (TIVA) is one of the anesthetic techniques that needs no inhalational agent but only an intravenous agent for induction and maintenance of anesthesia. Among drugs used in TIVA, propofol is the most popular agent. Rapid emergence and antiemetic characteristics of propofol are well known advantages but a dose dependent cardiovascular depressant effect is one of the disadvantages of this drug. Otherwise, ketamine, a dissociative agent, has been restricted in its use because of bad dreams, delirium and delayed emergence even though it has profound analgesic characteristics. However, ketamine has a stimulatory effect on the cardiovascular system, so it can raise blood pressure and pulse rate and in the case of TIVA, these properties can be advantageous when used with propofol. This study was aimed to decide whether TIVA using propofol and ketamine would have more stable vital signs during anesthesia and more rapid and smoother emergence in comparison with inhalational anesthesia using isoflurane. METHODS: Thirty two patients scheduled for elective general anesthesia were randomly allocated into two groups; I (inhalational anesthesia using isoflurane) group and PK (TIVA using propofol and ketamine) group. I group was controlled with isoflurane 1 - 1.5 vol% and the PK group was controlled with propofol 3 - 12 mg/kg/hr and ketamine 0.5 - 1.0 mg/kg/hr. Arriving at the recovery room, a single observer recorded the time to spontaneous movement, responses to painful pinch and verbal command, and orientation to age, name, place, date and time. At 5, 10, and 30 minutes after anesthesia, a PARS (postanesthesia recovery score), count-down test, and VAS (visual analogue scale) were checked. Postoperative events were checked in the recovery room and 24 hours lator. RESULTS: There was no significant difference in demographic data or characteristics of operation. Compared with the I group, the PK group had significantly rapid orientation responses on place, date and time. Restoration in the count-down test was more rapid in the PK group after 10 minutes in the recovery room. The VAS was lower in the PK group after 30 minutes in the recovery room. CONCLUSIONS: TIVA using propofol and ketamine has a more rapid emergence than inhalational anesthesia using isoflurane and better postoperative analgesic effect without respiratory depression.

Effects of Halothane, Enflurane and Isoflurane on Compliance and Resistance of the Total Respiratory System in Anesthetized Man / 대한마취과학회지

Bronchoconstrictions can occur by stimuli to the airway during anesthesia. Inhalational agents prevent or attenuate brochoconstriction and successfully inhibit reflexes of airway in asthmatic patients, and their mechanisms are well established. However, the effects of inhalational agents on the normal respiratory system is controversial. Therefore we studied the changes of compliance and resistance of the total respiratory system before and after administration of one of halothane, enflurane and isoflurane to unstimulated patients. We selected thirty adult patients without respiratory problems and excluded patients of receiving thoracic and abdomenal surgery because airway pressure might be changed by surgical manipulation. The patients without any premedication were ventilated with 50% oxygen by closed circuit ventilator(Physio-Flex(R)) after slow intravenous injection of thiopental sodium, fentanyl and vecuronium. We randomly allocated patients to one of three inhalational anesthetics( halothane, enflurane, isoflurane group). Then we intubated with I.D. 8 mm sized endotracheal tube for men and with I.D. 7 mm for women. Tidal volume and respiratory rates were maintained constantly during controlled ventilation and we increased concentration of inhalational agent by 0.5 MAC from zero to 1.5 MAC stepwise. At 10 minutes aft/er change of concentration of agent, we checked peak airway pressure, plateau airway pressure, mean airway pressure and end-tidal CO2 and then calculated compliance and resistance of the total respiratory system. We found that neither compliance nor resistance was changed by administration of or increasing concentration of halpthane, enflurane or isoflurane. The unstimulated normal airway in anesthetized patients was may be fully dilated, so that there was no more bronchodilatation after administration of inhalational agents.

The Effects of Inhalational Anesthetics on Memory and Cognitive Function / 대한마취과학회지

Many investigators have studied the effects of commonly used general anesthetic agents on CNS and found that a variety of congintive functions including psychomotor activity, assciative learning and short-term tasks were affected by anesthetice, and the ability of inhalstional anesthetics to depress or ebhance neuronal excitibility depends on the anesthetics, the anesthetic conectration, and particular brain region examined. To study the effects of inhalational snesthetics on meomory and congnitive function in human, we selected 123 patients scheduled for elective surgery, in ASA Phyaical Status Class I or II, for experimental group. But the patients undergoing a major surgery and with previous neuropsychiatrie history were excluded. As control group, 92 healthy volunteers were selected. Three tests Bender Gestalt Test, Trail Making B Test and Cognitive Cspacity Screening Examination-were performed on the properative day and the 4-5th postoperative day in experimental group. In control group these tests were performed tow times at the aame intervals. The mean performance ratos (II/ IX100) (i.e I is the score in the first examination and 3 id the score in the second examination)in experimental group were compared with those in control group. Results were as follows; 1. Bender Gestalt Test The mean performance ratios of control group 104.2+/-8.8 in man, 104.7+/-9.8 in woman and 104.5+/-9.4 in total control group. In experimental group they were 102.6+/-9.2 in man, 105.3+/-9.5 in woman and 104.9+/-9.2 in total experimental group. 2. Trail Making B Test The mean performance ratios of control group were 99.8+/-8.3 in ma, 97.6+/-10.0 in woman and 98.8+/-10.0 in total control group. In experimental group they were 99.2+/-13.5 in man, 97.9+/-14.0 in woman and 98.5+/-14.7 in total experimental group. 3. Cognitive Capacity Screening Examination The mean performance ratios of control group were 100.9+/-3.9 in man, 100.2+/-3.4 in woman snd 100.5+/-3.3 in total control group. In experimental group they were 99.4+/-2.1 in man, 101.6+/-3.7 in woman and 101.2+/-3.6 in total experimental The performance ratios of Congitive Capacity Sereening Examination in woman were signifi- cantly increased in experimental group, compared with control group. (p<0.05), but no differences were observed in total experimental group. The performance ratios of Bender Gestalt Test and Trail Making B Test in experimental group were increased more thatn those in control group but no statistical singificance was observed. According to these results we could confirm that inhalational anesthetics hsve no significant effects on memory and congnitive function.

The study of the effect of inhalational anesthetics on different areas of brain cortices under inhalational and intravenous combined anesthesia with EEG non-linear analysis / 解放军医学杂志

Objective To study the effect of inhalational anesthetics on brain cortices under inhalational and intravenous combined anesthesia. Methods 45 patients were randomly divided into isoflurane group (n=15), sevoflurane group (n=15) and desoflurane group (n=15). The narcosis was maintained with inhalational and intravenous combined anesthesia. The EEG non-linear parameters including approximate entropy (ApEn) and correlation dimension (D 2 ) were recorded during operation periods. BP, HR, and SpO 2 were monitored routinely. Results Comparing with that at entrance to the operating room, the EEG activities of frontal and temporal cortices after anesthesia were more suppressed than other cortices. Comparing with that at entrance to the operating room, ApEn and D 2 were significantly declined in the three experimental groups (P