Comparison of enflurane and propofol in electroconvulsive therapy, a randomized crossover open preliminary study on seizure duration and anaesthetic recovery.

BACKGROUND AND OBJECTIVES: Electroconvulsive therapy (ECT) is commonly used for treatment of depression, mania and affective disorders. Anaesthetics for general anaesthesia during ECT should have rapid onset, rapid emerge, not interfere with seizure activity and not shorten seizure duration. The aim of this study is to compare effects of enflurane, a pro-convulsive anaesthetic agent, and propofol on seizure durations, postictal suppression index and recovery times during electroconvulsive therapy. METHODS: Unpremedicated subjects were divided into two groups according to induction of anaesthesia. Patients were induced for ECT with 5% enflurane in group E and 1.2mg.kg(-1) propofol in group P until loss of consciousness. The durations of electroencephalogram (EEG) and motor seizures, postictal suppression index, time to spontaneous breathing, duration of eye opening, and obeying commands were recorded. RESULTS: There was no statistically significant difference between the groups regarding motor and EEG seizure times and postictal suppression index on the EEG records. Recovery times (times of starting spontaneous breathing, eye opening, and obeying command) were significantly shorter in group E compared to group P. No nausea or vomiting were observed and no ECG abnormality was noted except transient sinus bradycardia and sinus tachycardia. CONCLUSIONS: Although sufficient seizure for the treatment was provided during enflurane anaesthesia, any additional benefit was not revealed regarding seizure times or postictal suppression index when compared to propofol anaesthesia. On the other hand, recovery times after enflurane anaesthesia were shorter than propofol anaesthesia. However, there is still a need for further study in different ETCO(2) levels.

[Effect of volatile inhalational anesthetics on cerebral blood volume and oxygen status in children].

The investigation evaluated the effect of various volatile anesthetics on cerebral blood volume and oxygen status in sick children at the stage of anesthesia induction. Ninety-two children were distributed into 3 groups: Groups 1 (n = 36) and 2 (n = 24) underwent stepwise induction with halothane and enflurane, respectively. Group 3 (n = 32) had vital capacity rapid inhalation induction with sevoflurane. Cerebral oximetry (NIRS method) was used to measure the content of hydroxyhemoglobin, deoxyhemoglobin, the total level of hemoglobin and to assess regional cerebral tissue saturation (rSO2). Halothane was ascertained to increase cerebral blood volume by 20.5% whereas enflurane and sevoflurane increased it only by 8.8 and 9.0%, respectively. In all cases, the value of rSO2 remained comparatively high, by exceeding the baseline level by 3-5%.

Pharmacodynamics and pharmacokinetics of high-dose oxycodone infusion during and after coronary artery bypass grafting.

OBJECTIVE: In small to moderate doses, oxycodone has similar analgesic efficacy to morphine with fewer side effects. The present study evaluated the pharmacokinetics and dynamics of high doses of oxycodone during anesthesia for primary coronary artery bypass grafting. DESIGN: A randomized, prospective clinical evaluation. SETTING: A major Scandinavian university clinic. PARTICIPANTS: Two groups with 10 patients each were studied. INTERVENTIONS: Invasive hemodynamics, echocardiograms, and electrocardiograms were monitored. Oxycodone kinetics, histamine liberation, and plasma cortisol levels were measured. Anesthesia was induced with 1.0 mg/kg of oxycodone and, thereafter, in a random order, maintained with a continuous infusion of oxycodone at a rate of either 0.5 mg/kg/h (group OX 0.5, 10 patients) or 1.0 mg/kg/h (group OX 1.0, 10 patients). An additional bolus dose of 0.5 mg/kg (OX 0.5) or 1.0 mg/kg (OX 1.0) of oxycodone was given before the incision. Enflurane was administered according to hemodynamic criteria. MEASUREMENTS AND MAIN RESULTS: The induction of and the course of anesthesia were hemodynamically stable in all patients. Enflurane was given to every patient. The mean total doses of oxycodone were 3.5 mg/kg (OX 0.5) and 6.2 mg/kg (OX 1.0). The median t(1/2) of oxycodone varied from 5.1 to 5.9 hours. No hemodynamic differences were found between the groups. No histamine liberation was detected. During anesthesia, the predominant waves in the EEG were theta;- and delta-waves. The mean times to awakening were 3.8 hours and 7.0 hours in the groups OX 0.5 and 1.0, respectively. All patients were intubated until the first postoperative morning. No recall of awareness was reported. CONCLUSION: A combination of oxycodone and enflurane provides hemodynamically stable anesthesia. No advantages were gained with the higher dose. Elimination of oxycodone was slower than reported previously.

Resecciones hepáticas: importancia de la técnica quirúrgica y anestésica en el consumo de sangre y hemocomponentes / Hepatic resections: relevance of the surgical and anesthetic techniques regarding the intraoperative hemoderived used

Antecedentes: La cirugía de resección hepática, se ha caracterizado desde sus inicios por una alta tasa de morbimortalidad, relacionada esencialmente con el riesgo de hemorragia y la necesidad de transfusiones masivas. La experiencia acumulada en 900 intervenciones, permitió el desarrollo de procedimientos quirúrgicos y anestésicos que disminuyeron el consumo de sangre y mejoraron los resultados. Objetivo: Conocer el efecto sobre el consumo de hemocomponentes y la evolución postoperatoria inmediata a partir de modificaciones en la técnica anestésica, quirúrgica, en enfermos sometidos a resecciones hepáticas, practicadas por el mismo equipo anestésico-quirúrgico. Material y método: 2 grupos de enfermos sometidos a resecciones hepáticas comparables. Grupo I: 45 enfermos consecutivos intervenidos entre 1983/1987. Técnica anestésica: Neuroleptoanestesia y Anestesia inhalatoria. Transfusión de sangre de acuerdo a la estimación de pérdidas. El parámetro intraoperatorio más importante fue la presión arterial. Grupo II: 45 enfermos consecutivos intervenidos en el año 2000. Técnica anestésica: endovenosa. Transfusión de sangre: separada en hemocomponentes y sangre autóloga, de acuerdo a guías de la ASA. Parámetro intraoperatorio más importante: presión arterial y presión venosa central. La última variable debe permanecer por debajo de 5 cm de H2O. Se utilizaron además drogas vasoactivas. Resultados: Grupo I: transfundidos: 77,8 por ciento, Grupo II: transfundidos 53,3 por ciento (p=0,027). Promedio de horas en respirador: Grupo I: 18,2, Grupo II: 4 (p=0,0001). Promedio de días en Unidad de Cuidados Intensivos: Grupo I: 9,11, Grupo II: 2,6 (p=0,06). Promedio de días de internación: Grupo I: 12, Grupo II: 7 (p=0,006). Morbilidad: Gupo I: 71 por ciento, Grupo II: 26,7 por ciento (p=0,0001). Mortalidad: Grupo I: 6,7 por ciento, Grupo II: 0 por ciento (p=0,24). Conclusiones: Las modificaciones en la técnica quirúrgica, anestésica y transfusional permitieron: Disminuir los requerimientos transfusionales, reducir el uso de la asistencia respiratoria mecánica, acortar la estadía hospitalaria y mejorar la morbilidad (AU)

Effects of enflurane, isoflurane, sevoflurane and desflurane on reperfusion injury after regional myocardial ischaemia in the rabbit heart in vivo.

It is known that volatile anaesthetics protect myocardial tissue against ischaemic and reperfusion injury in vitro. In this investigation, we have determined the effects of the inhalation anaesthetics, enflurane, isoflurane, sevoflurane and desflurane, administered only during early reperfusion, on myocardial reperfusion injury in vivo. Fifty chloralose-anaesthetized rabbits were subjected to 30 min of occlusion of a major coronary artery followed by 120 min of reperfusion. Left ventricular pressure (LVP, tip-manometer), cardiac output (CO, ultrasonic flow probe) and infarct size (triphenyltetrazolium staining) were determined. During the first 15 min of reperfusion, five groups of 10 rabbits each received 1 MAC of enflurane (enflurane group), isoflurane (isoflurane group), sevoflurane (sevoflurane group) or desflurane (desflurane group), and 10 rabbits served as untreated controls (control group). Haemodynamic baseline values were similar between groups (mean LVP 106 (SEM 2) mm Hg; CO 281(7) ml min-1). During coronary occlusion, LVP and CO were reduced to the same extent in all groups (LVP 89% of baseline; CO 89%). Administration of inhalation anaesthetics during early reperfusion further reduced both variables, but they recovered after discontinuation of the anaesthetics to values not different from control animals. Infarct size was reduced from 49 (5)% of the area at risk in the control group to 32 (3)% in the desflurane group (P = 0.021), and to 36 (2)% in the sevoflurane group (P = 0.097). In the enflurane group, infarct size was 39 (5)% (P = 0.272). Isoflurane had no effect on infarct size (48 (5)%, P = 1.000). The results show that desflurane and sevoflurane markedly reduced infarct size and therefore can protect myocardium against reperfusion injury in vivo. Enflurane had only a marginal effect and isoflurane offered no protection against reperfusion injury in vivo. These different effects suggest different protective mechanisms at the cellular level.

The effects of anesthetic technique on the hemodynamic response and recovery profile in coronary revascularization patients.

This study was undertaken to assess the effects of propofol (versus enflurane, fentanyl, and thiopental) on hemodynamic stability and recovery characteristics when used for maintenance of anesthesia during elective coronary artery bypass grafting (CABG) procedures. Ninety premedicated patients scheduled for elective coronary revascularization had anesthesia induced with fentanyl 25 micrograms/kg intravenously (i.v.). When the mean arterial blood pressure (MAP) increased 10% above preoperative baseline values, patients were randomized to receive one of four anesthetic treatments: enflurane, 0.25-2.0%; fentanyl, 10-20 micrograms/kg i.v. bolus doses; propofol, 50-250 micrograms.kg-1.min-1 i.v.; or thiopental, 100-750 micrograms.kg-1.min-1 i.v.. The maintenance anesthesia was titrated to achieve hemodynamic stability (i.e., maintain the MAP within 10% of the baseline values and heart rate [HR] within 20% of the baseline values). After bypass, anesthetic and cardiovascular drugs were titrated to maintain the MAP > 65 mm Hg and the cardiac index (CI) > 2.3 L.min-1.m-2. Recovery was assessed by noting the times at which patients first opened their eyes, responded to verbal communication, correctly responded to specific commands, underwent tracheal extubation, and were discharged from the intensive care unit (ICU). Although less intraoperative hypertension was noted in the propofol-treated patients (19 +/- 11 min vs 38 +/- 26 min, 30 +/- 24 min, and 30 +/- 23 min in the enflurane, fentanyl, and thiopental groups, respectively) (P = 0.04), the incidence of hypotension did not differ significantly among the groups. Vasopressor drugs were required more often during the prebypass period in fentanyl and propofol patients (4/22 and 5/23, respectively) compared to the thiopental group (0/21) (P < 0.05). During CPB, fentanyl-treated patients required vasoconstrictors more often than patients in the other three treatment groups (14/22 vs 6/24, 4/23, and 5/21 in the enflurane, propofol, and thiopental groups, respectively) (P < 0.01). Although fentanyl-treated patients had significantly greater requirements for inotropic support during weaning from CPB than propofol-treated patients (14/22 vs 7/23) (P < 0.038), there were no significant differences among the groups in the postbypass or ICU periods. Propofol-treated patients responded to verbal stimuli (2.1 +/- 1.3h vs 4.0 +/- 3.5h, 4.7 +/- 2.7h, and 5.6 +/- 3.6h in the enflurane, fentanyl, and thiopental groups, respectively) (P = 0.01) and followed commands earlier (propofol 7.3 +/- 5.2h vs enflurane 12.5 +/- 5.7h, fentanyl 13.1 +/- 6.6h, and thiopental 12.8 +/- 6.7 h) (P = 0.01).(ABSTRACT TRUNCATED AT 400 WORDS)

Enflurane and isoflurane reduce reperfusion dysfunction in the isolated rat heart.

We evaluated the possible cardioprotective effects of enflurane (E) and isoflurane (I) in isolated rat hearts subjected to 40 min normothermic arrest. After reperfusion, hearts were stimulated with adrenaline to evaluate their systolic reserves. In hearts not receiving I or E, adenosine triphosphate (ATP) was reduced from 23.0 +/- 0.8 to 9.3 +/- 1.1 mumol/g dry weight (means +/- SEM; P < 0.001) after arrest. This was associated with a significant reduction in ventricular work (Wt) from 13.6 +/- 0.7 to 1.6 +/- 0.7 mW (P < 0.001). Adrenaline partially restored Wt but not the ATP. E and I given only during normothermic arrest (in the cardioplegic solution) resulted in reductions in ATP similar to the hearts not receiving the drugs. However, on reperfusion and subsequent administration of adrenaline, hearts subjected to the anesthetic drugs performed as well as hearts before arrest. For example, in hearts not exposed to I or E, the Wt after the elective arrest was 1.55 +/- 0.05% (mean +/- SEM) of the pre-arrest value. This was significantly less than hearts exposed to either one of the inhalational agents (40.02 +/- 3.49% of the pre-arrest value; P < 0.0001). Adrenaline improved function in hearts which did not receive I or E to 55.02 +/- 12.80% of the pre-arrest value, but this was significantly less than the Wt performed by the hearts exposed to the anesthetic agents (122.67 +/- 7.78% of pre-arrest value; P < 0.001). This beneficial effect of I and E during reperfusion probably is mediated by the effect of the anesthetic agents on Ca2+ slow channels. The effect could not be ascribed to depression of global myocardial contractile function associated with I and E.

Treatment of intraoperative hypertension with enflurane, nicardipine, or human atrial natriuretic peptide: haemodynamic and renal effects.

The purpose of this study was to assess the effects of the calcium entry blocker nicardipine and alpha human atrial natriuretic peptide (hANP) on antihypertensive and diuretic activity in hypertensive surgical patients. The site of the diuretic actions of these drugs along the nephron were also investigated by measuring the excretion rate of inorganic phosphate (PO4). Hypertension during gastrectomy was treated by increasing the concentration of enflurane, by nicardipine infusion (0.5-2.0 micrograms.kg-1 x min-1), or by hANP infusion (0.05-0.2 microgram.kg-1 x min-1) under general anaesthesia. Enflurane, nicardipine and hANP all decreased arterial pressure to the same extent. Urine flow, Na and PO4 excretion increased following the administration of nicardipine or hANP. Fractional distal reabsorption of sodium was suppressed from 89.7 +/- 2.8% to 82.1 +/- 5.0% by the hANP, but not by the nicardipine infusion. Creatinine clearance was increased by hANP infusion, but did not change in the nicardipine group. It is concluded that nicardipine and hANP can be used safely for the treatment of hypertension during surgery. Both drugs induced phosphaturic diuresis, but the site of action of the two drugs on the nephron may be different. Phosphate reabsorption is considered to occur largely in the renal proximal tubule, so that its appearance in the urine in increased quantities without the change of renal circulation in the nicardipine group suggests a proximal tubular action of this drug. However, the site of action of hANP in the kidney was not determined because GFR increased and distal sodium reabsorption was suppressed due to the drug infusion.

Inhaled anaesthetic agents: from halothane to the present day.

Despite the enormous resources spent on research and development, only two new volatile agents have been introduced into anaesthetic practice in the UK since the introduction of halothane. This article reviews their properties and looks towards changes in volatile anaesthetic availability in the near future.

Hipotensäo induzida com bloqueadores alfa e beta 1 halogenado: comparaçäo entre enflurano, halotano e isoflurano em rinoplastias / Deliberated hypotension using alfa and beta one blocks and halogenated agents: comparison among eflurane, halothane and isoflurane in rhinoplasty

A técnica de hipotensäo induzida pelo bloqueio dos receptores adrenérgicos alfa e beta 1 foi avaliada tendo como base a anestesia geral com halogenado (enflurano, halotano ou isoflurano), com o objetivo de comparar a repercussäo quanto à PAS, PAD, FC; avaliar o consumo médio de: droperidol, fentanil, metoprolol, enflurano, halotano e isoflurano; foi medido o tempo médio da duraçäo das anestesias e, também, o tempo de recuperaçäo anestésica. Sessenta pacientes com idade variando de 14 a 45 anos, ASA I e II, foram submetidos à rinoplastia. A medicaçäo pré-anestésica foi com diazepam 10 mg por via oral, 45 a 60 min antes da induçäo da anestesia. A induçäo anestésica foi com diazepam 10 mg por via oral, 45 a 60 min antes da induçäo da anestesia. A induçäo da anestésica constou de fentanil (0,002-0,003 mg.kg elevado a menos 1), diazepam (0,15-0,20 mg.kg elevado a menos 1), etomidato (0,2 mg.kg elevado a menos 1) e toxiferina (0,3 mg.kg elevado a menos 1). Os pacientes foram divididos em três grupos de 20 pacientes cada, de acordo com o agente inalatório utilizado (enflurano, halotano e isoflurano). Para induzir hipotensäo arterial as dose de droperidol foram de 5 a 10 mg, as de metroprolol de 5 a 10 mg. Os dados foram analisados estatisticamente. Os grupos foram homogêneos em relaçäo à idade, altura e peso. Houve diferença significativa entre as médias de pressöes arteriais e diastólicas antes da induçäo da hipotensäo (M1-M4) e as médias de pressöes sistólicas e diastólicas mínimas de manutençäo (M6) (p<0,05); entretanto, näo houve diferença significativa entre os grupos. Houve diferença significativa entre as médias de frequências cardíacas após a intubaçäo orotraqueal (M4) e as médias mínimas de manutençäo sob hipotensäo induzida (M6) (P,0.05), mas näo entre os grupos. Com relaçäo às drogas empregadas, ocorreu diferença significativa (p<0,05) entre as doses de metoprolol requeridas pelo grupo de isoflurano em relaçäo ao enflurano e isoflurano no mesmo tempo de administraçäo (p<0,05). Houve hipotensäo que necessitou tratamento no grupo de halotano mais significativo (p<0,05) que nos outros dois grupos. Em nenhum dos grupos observou-se disritmia cardíaca. Pode-se concluir que a hipotensäo arterial induzida pelo método descrito com qualquer dos halogenados testados é de fácil manuseio, com incidência de complicaçöes esporádicas e insignificantes...

[Halothane or enflurane treatment in life-threatening asthma].

We performed inhalation anesthetic therapy in an attempt to produce improvement in cause of life-threatening asthma, which were standard pharmacological therapy. We analysed the results obtained in 6 cases given inhalation anesthetic therapy (4 cases were treated with halothane and 2 cases with enflurane). The following observations were made: 1) The criteria for starting inhalation anesthetic therapy were persistent hypoxycemia or hypercapnia, persistently high inspiratory intra-airway pressure, clinical exhaustion and bronchial toilet with bronchofiberscope. 2) We treated the patients with halothane concentrations of between 1.0 and 2.0% and enflurane concentrations of between 1.0 to 4.2%. 3) No major complications were observed in inhalation anesthetic therapy.

[Evaluation of tissue perfusion by simultaneous monitoring of aortic flow rate and capnography]. / Evaluation de la perfusion tissulaire par surveillance simultanée du débit aortique et de la capnographie.

Ten patients under general anaesthesia were subjected to non-invasive haemodynamic monitoring, together with arterial gasometry and capnography. When enflurane was administered for maintenance anaesthesia, a 33 percent fall in aortic flow rate was observed (P less than 0.01), together with prolongation of the pre-ejection period and left ventricular pre-ejection/ejection ratio, an increase of central venous pressure and total vascular systemic resistances. The end-expiratory CO2 (Pet CO2) was reduced by 13 percent (P less than 0.05). There was no significant variation in arteriolo-alveolar CO2 difference (P(a-A)CO2). Under dobutamine (mean dose: 3.4 +/- 0.5 micrograms/kg/min), the haemodynamic parameters returned to their initial values. Pet CO2 rose above its initial level (+ 12 percent; P less than 0.05), but P(a-A)CO2 was not significantly modified. The variations of Pet CO2 were parallel with those of aortic flow rate. It is concluded that the changes in Pet CO2 observed during haemodynamic modifications could be used as markers for qualitative evaluation of tissue perfusion.

Nitrous oxide, nausea, and vomiting after outpatient gynecologic surgery.

Postanesthetic nausea and vomiting can delay discharge of outpatients and can cause occasional admissions to hospital. Nitrous oxide (N2O) has been thought to increase this frequency, but previous studies have been indecisive. One hundred eighty-five unpremedicated outpatients undergoing laparoscopic tubal ligation were studied to determine the effect of N2O on postanesthetic nausea and vomiting. The patients were divided by registration number, intubated, and given mixtures of either N2O-O2 enflurane or air-O2 enflurane. Intravenous (IV) lidocaine, administered initially prior to intubation to control bucking, was later omitted in randomly chosen cases to determine its effect. The overall prevalence of nausea and vomiting was 29.2% with N2O and 9.3% with air (p less than 0.001). While the lidocaine subseries was small, it appeared to prevent nausea and vomiting, particularly when N2O was omitted. Further study is justified. Fentanyl, given postoperatively for pain, did not increase the prevalence of nausea and vomiting. It was concluded that N2O is associated with an increased prevalence of nausea and vomiting.