Comparative study of the behavior of isoflurane and halothane in pediatric anesthesia]

This study involves 60 patients below the age of 14 years who were subjected to short duration surgical procedures under inhalation anesthesia with halothane and isoflurane at equivalent CAM in 50% protoxide. The objectives of the study were: a) to establish which of the two inhalational agents produced the more rapid anesthetic induction; b) to determine which exerted the more marked potentiation of the neuromuscular blockade induced by succinylcholine, and c) to compare the anesthetic quality during the induction and recovery periods of both halogenated agents. Induction was more rapid after halothane (mean induction time of 2.91 +/- 0.97 min) than after isoflurane (mean induction time of 6.24 +/- 2.88 min; p less than 0.001). Potentiation of succinylcholine induced neuromuscular blockade was greater after isoflurane than after halothane: the mean time of apnea was 4.56 +/- 1.82 min for isoflurane and 3.41 +/- 1.63 min for halothane (p less than 0.05). Undesirable effects were larger in patients treated with isoflurane than in patients anesthetized with halothane (mean score: 12.60 +/- 3.53 points vs 14.41 +/- 2.33 points; p less than 0.001). The analysis of anesthetic quality during the recovery period gave a mean punctuation of 16.62 +/- 2.21 to patients treated with halothane, whereas patients anesthetized with isoflurane showed a lower score of 14.25 +/- 1.99 points (p less than 0.001). The higher scores corresponded to the most well tolerated anesthetic induction and recovery. The highest attainable score in this study was 18.     

Atracurium with halothane and isoflurane in pediatric anesthesia

The study was carried out to assess the effects of atracurium neuromuscular blockade in children anaesthetized with N2O:O2: halothane vs N2O:O2: isoflurane. Thirty-two ASA I-II children, age 1-13 yr, undergoing elective surgery, were divided into two groups according to age and the mode of anaesthesia induction. Anaesthesia was induced in the younger children (group 1: 1-6 yr) with nitrous oxide and inspired halothane or isoflurane in oxygen via a face mask. Intravenous thiopental (6-7 mg/kg-1) was used to induce anaesthesia in older children (group 2: 7-13 yr). Each group of patients was randomly allocated to two groups each receiving halothane (group A: n = 8) or isoflurane (group I: n = 8). Halothane 0.8% end-tidal and isoflurane 1% end-tidal as anaesthesia maintenance. A bolus dose of atracurium 0.35 mg/kg-1 was administered. Premedication consisted of oral flunitrazepam (0.04 mg/kg-1) and bellafoline (0.02 mg/kg-1). Heart rate (by electrocardiography), arterial pressure (by auscultation) were monitored. Then end-expired carbon dioxide concentration was maintained at 30-40 mmHg. Neuromuscular transmission was evaluated by response to indirect stimulation (TOF) of the ulnar nerve at the wrist via surface electrodes. Conditions for endotracheal intubation were excellent in 25 of the children, good in 6 and poor in 1. The intubation was carried out within 112 s (group 1A), 130 s (group 1 I), 112 s (group 2A) and 135 s (group 2 I) following the administration of atracurium. The maximum twitch depression was recorded in the isoflurane groups.(ABSTRACT TRUNCATED AT 250 WORDS)     

丙泊酚反馈靶控输注静脉麻醉与异氟醚吸入麻醉的临床效果比较

目的　比较丙泊酚反馈靶控输注 (TCI)静脉麻醉与异氟醚吸入麻醉的临床效果。方法4 0例行腹腔镜胆囊切除术的患者随机分成两组。丙泊酚组 (n =2 0 )采用丙泊酚闭合环路TCI ,靶浓度 4 μg/ml,以脑电双频谱指数 (BIS) =5 0、MAP =80 %基础值作为反馈指标。异氟醚组 (n =2 0 )采用 3 4 %异氟醚吸入诱导 ,0 8%～ 2 %维持。术中监测HR、MAP、BIS等指标。结果　丙泊酚组入睡时间和诱导时间显著少于异氟醚组 (P <0 0 5 )。术中丙泊酚组生命体征维持相对平稳 ;术后苏醒明显优于异氟醚组 ,麻醉并发症明显减少。结论　用丙泊酚进行以患者自身MAP、BIS为目标的反馈TCI,能及时地调节及维持有效麻醉深度 ,对血液动力学的干扰较小 ,对腹腔镜手术是一种优于吸入麻醉的方法     

Psychological eff-cts of halothane and isoflurane anesthesia.

Psychological effects of halothane (16 subjects) and isoflurane (24 subjects) anesthesia on healthy young men were assessed prior to and 2,3,4,6,8, and 30 days after anesthesia. The results with each agent were compared with each other and with the results for 41 unanesthetized controls. Both agents altered psychological function. Changes in function were greatest 2 days after anesthesia; function had returned to near preanesthesia values 8 days after anesthesia. Only slight symptom and mood effects and no intellectual effect attributable to anesthesia remained 30 days after anesthesia. Halothane produced greater negative effects on moodds and symptoms and tended to produce greater negative effects on intellectural function than did isoflurane. The differences between the two anesthetics are consistent with differences in their solubilities and metabolism.     

Microcirculatory response to halothane and isoflurane anesthesia.

Microcirculatory hemodynamics are often used to monitor tissue and organ survival. This study investigated the effect of halothane and isoflurane anesthesia on peripheral microcirculation using the cremaster muscle during intravital microscopy. Twenty-three Sprague-Dawley rats were studied in four groups. Two groups served as controls and did not undergo flap isolation but did receive halothane (N = 6) or isoflurane (N = 5). After induction with a single dose of intraperitoneal pentobarbital (40 mg per kilogram), rats were ventilated with either 2 minimum alveolar concentration (MAC) halothane or 2 MAC isoflurane. Esophageal temperature, electrocardiography, central venous pressure, mean arterial pressure, and blood gases were measured over 4 hours. In groups receiving surgery with either halothane (N = 6) or isoflurane (N = 6), the cremaster muscle was isolated on the neurovascular pedicle. Microcirculatory responses to both halothane and isoflurane anesthesia were evaluated by measuring red blood cell (RBC) velocity, vascular diameters in arterioles (A1, A2-1, A2-2, and A3) and the main venule (V1), functional capillary perfusion, and leukocytic endothelial interactions in postcapillary venules (rolling, adherent, and transmigrating leukocytes). Hemodynamic variables were compared among all four groups, and microcirculatory variables were compared between the two surgical groups. During isoflurane anesthesia in animals with flaps, significantly higher (p < 0.05) RBC velocities were recorded in arterioles A1 (24.4%), A2-2 (28.2%), and A3 (17.4%). Capillary perfusion was significantly higher in animals with flaps and halothane anesthesia (17.8%; p < 0.05). The number of rolling leukocytes (39.4%) was significantly higher during isoflurane anesthesia in animals with flaps (p < 0.05). Better flow hemodynamics in the peripheral microcirculation were seen during halothane anesthesia, and were confirmed by greater functional capillary perfusion and fewer activated leukocytes. In the isoflurane group, RBC velocity alone cannot serve as an indicator of microcirculatory function.     

Comparative coronary vascular reactivity and hemodynamics during halothane and isoflurane anesthesia in swine

To assess the dose-response effects of isoflurane and halothane anesthesia on hemodynamics and coronary artery reactivity, the authors studied myocardial hyperemic responses following brief single artery flow arrests in 21 open chest, isocapnic swine in which arterial blood pressures and cardiac outputs were recorded. A specially designed Doppler probe was used to measure the peak and time course of coronary blood flow velocity in the left anterior descending coronary artery (LAD) after 15-s LAD occlusions. The ratio of peak velocity of blood flow to resting velocity (coronary reserve), relative repayment of flow debt, and duration of hyperemic responses were studied. Surgery was performed at MAC end-tidal concentrations ([Et]isoflurane = 1.45%. [Et]halothane = 1.25%) of isoflurane (n = 7) or halothane (n = 7), and recordings were made after 15-min steady state [Et]agent at 0.5, 1, 1.25, 1.5, 1.75, 2 MAC, and further 0.5 MAC increments until the demise of each animal. To compare coronary reactivity at similar coronary pressures, an aortic snare was used to elevate arterial pressures in a third group of halothane anesthesized pigs (n = 7) to those in the previously studied isoflurane group at each MAC level. There were three major differences between halothane and isoflurane. First, cardiac depression (reduction in arterial pressure, cardiac output, and stroke volume) was less with isoflurane compared with halothane anesthesia. Second, with halothane anesthesia, there was a marked decrease in coronary reactivity independent of coronary perfusion pressures with marked, dose-dependent reductions in both coronary reserve and relative flow repayment. During isoflurane anesthesia, coronary reactivity and coronary reserve was well preserved within physiologic limits up to 1.75 MAC [Et]. Third, halothane anesthesized pigs died in cardiac collapse at much lower agent concentrations than with isoflurane (no animals survived 1.75 MAC halothane, whereas all animals survived 2.5 MAC isoflurane). Therefore, pigs anesthesized with isoflurane had greater coronary reserve, better preserved cardiac function, and greater tolerance to increasing agent concentration than pigs anesthesized with halothane.     

Comparison of inhalation induction with isoflurane or halothane in children

Thirty-six children (mean age 2.4 years) premedicated with oral chloral hydrate 70 mg kg-1 and atropine 0.03 mg kg-1 were anaesthetized with either 3.75% isoflurane or 2.5% halothane in 70% nitrous oxide in oxygen. The eyelash reflex disappeared in 39 +/- 7 s (mean +/- SD) with isoflurane and in 56 +/- 16 s with halothane (P less than 0.001). Tachypnoea was seen with both anaesthetics. Coughing, breath holding, stridorous breathing and respiratory depression were seen during isoflurane but not during halothane induction (P less than 0.01). In nine of 20 children anaesthetized with isoflurane, the ventilation had to be assisted before intubation. Endotracheal intubation was possible in 224 +/- 35 s with isoflurane and in 281 +/- 64 s with halothane (P less than 0.01). Intubating conditions were satisfactory in 80% of the children anaesthetized with either volatile agent. Cardiovascular responses to endotracheal intubation were minimal with both anaesthetics. No cardiac dysrhythmias were noted. Heart rate was higher during isoflurane than during halothane induction. Diastolic arterial pressure was lower during isoflurane than during halothane induction immediately and 5 min after intubation.     

Comparison of halothane and isoflurane for rapid anesthetic induction

To study the hypothesis that isoflurane will induce anesthesia faster than halothane when given by a single vital capacity breath technique, we studied 20 ASA I and II adults who breathed approximately 4.5 MAC equivalents of either vapor. The patients, randomly assigned to receive either agent, were fully preoxygenated and monitored for cardiovascular, respiratory, and EEG parameters. All subjects were premedicated with 5 micrograms/kg fentanyl IV 5 min before induction. Time to loss of consciousness was significantly longer with halothane than with isoflurane (86 +/- 4 vs 38 +/- 2 sec, respectively) although there were no clinically remarkable differences in cardiovascular or respiratory variables. Patients given halothane had a greater excitatory phase on EEG, whereas those given isoflurane had low frequency predominance. Overall rapid inhalation induction was well-received by all patients and was significantly faster with isoflurane.     

Plasma lidocaine concentrations during epidural blockade with isoflurane or halothane anesthesia.

Because isoflurane maintains hepatic blood flow at higher flows than halothane, we proposed that the elimination of lidocaine would be different between these two volatile anesthetics. The plasma lidocaine concentrations were determined in 14 female patients undergoing epidural blockade plus isoflurane anesthesia and compared with those obtained during halothane anesthesia for lower abdominal surgery. General anesthesia was maintained with isoflurane (0.46% +/- 0.04% [mean +/- SE] inspired, n = 7) or halothane (0.48% +/- 0.05% inspired, n = 7) and 67% nitrous oxide in oxygen. All patients received 2% lidocaine solution, 10 mL as a bolus dose and continuous administration at a rate of 10 mL/h, through the epidural catheter. The plasma lidocaine concentrations over 180 min after the epidural injection in patients receiving isoflurane were similar to those in patients receiving halothane. The results suggest that low inspired concentrations of isoflurane do not reduce plasma lidocaine concentrations in patients during epidural blockade, compared with halothane.     

Comparative effects of halothane and isoflurane anesthesia on the ultrastructure of human hepatic cells

The effects of halothane and isoflurane on the ultrastructure of the liver cells in adult patients with normal liver-function tests were compared. After induction of anesthesia with thiopental, fentanyl, and pancuronium, 18 patients were randomly divided into three groups of six each. Anesthesia was maintained with droperidol (droperidol group), with halothane (1.7 MAC, halothane group), or with isoflurane (1.7 MAC, isoflurane group). During the surgical procedure, 1 hr after the induction, a liver biopsy was performed in each patient and processed for light and electron microscopy. All biopsies were normal on light microscopy. On electron microscopy, no mitochondrial abnormalities were found. In all three groups, irregular nuclear membranes, dilation of the rough endoplasmic reticulum, and vesiculation of the smooth endoplasmic reticulum were seen, without any significant differences between the groups. There were significantly more lysosomes in the hepatocytes of patients receiving halothane than in the hepatocytes of patients receiving isoflurane or droperidol. This study shows that halothane can induce ultrastructure abnormalities very early after the beginning of its administration while, under the same conditions, isoflurane does not.     

Halothane and isoflurane anesthesia in pediatric outpatients

Halothane or isoflurane was used to induce anesthesia in children scheduled for outpatient surgical procedures. Both agents were administered at predetermined rates until comparable concentrations in end-expired air were reached. Induction of anesthesia, as well as the time taken before tracheal intubation was possible, was protracted in patients given isoflurane. In the recovery period, the times taken to respond to pharyngeal suction, to tracheal extubation, and to the first cry were similar for both anesthetic agents.     

Quality of recovery after general anesthesia with isoflurane or halothane

The quality of recovery and the time required for it were compared in two groups of 20 patients after general anaesthesia with isoflurane or halothane for elective head and neck surgery. The groups were comparable with regard to age, sex ratio, ASA physical status, type of surgery and duration of anaesthesia. After premedication with diazepam and atropine, a standard induction technique was used (thiopentone, succinylcholine), avoiding opiates and sedatives. Maintenance was assured with a mixture of 30% oxygen, 70% nitrous oxide and isoflurane or halothane. The time between the end of administration of anaesthetic drugs and eye opening was 7.15 +/- 2.9 min in the isoflurane group, and 11.0 +/- 4.7 min in the halothane group (p less than 0.01). The differences between the times for the return of spatial and temporal orientation and of mental arithmetic were not significant, though they were clinically clearly perceptible. The patients were less sleepy, livelier and less agitated in the isoflurane group in the first hour of recovery. Recovery was more rapid after general anaesthesia with isoflurane, and of better clinical quality.