Changes in the electroretinogram during enflurane anesthesia

We have investigated a method of intraoperative monitoring of anesthetic depth using the electroretinogram (ERG). The effects of enflurane on ERG were studied in 12 patients undergoing surgical procedures. Recordings were made at 0%, 0.8%, 1.7% end-tidal enflurane concentrations. There were statistically significant increases in the latencies of the a-waves, b-waves and oscillatory potentials (OP) with increasing concentrations of enflurane. The amplitudes of the a-waves were reduced with increasing concentrations of enflurane, but the amplitudes of the b-waves did not change. The latencies of OP were thought to be the most sensitive indicator of the anesthetic depth among these parameters. To apply this technique to clinical practice, there were many problems to be solved. However, this may be one of useful monitors of anesthetic depth in future.     

Cortisol levels during enflurane anesthesia in man

Serum cortisol levels were determined in 44 patients who underwent hysterectomy under enflurane or under halothane anesthesia by means of a radioimmunoassay technique. Of the 44 patients, in 21 anesthesia was maintained by enflurane and d-tubocurarine and 23 patients maintenance of anesthesia was carried out by halothane and d-tubocurarine. Blood samples for serum cortisol estimations were obtained from each patient before induction of anesthesia, 10 min. after induction, 10 min. after skin incision, at the end of the operation and in the ward on the fourth postoperative day. Cortisol levels increased in both groups at the end of the operation with a significantly higher mean value in the enflurane group (p less than 0.05) compared to that of the halothane group.     

Neuromuscular effects of pipecuronium during sevoflurane anesthesia compared with isoflurane and enflurane anesthesia

We evaluated the neuromuscular effects of pipecuronium during anesthesia with equipotent concentrations of either sevoflurane, isoflurane or enflurane.Twenty-seven patients scheduled for minor elective otolaryngeal or plastic surgery were studied and randomly assigned to 3 groups, one group per anesthetic agent. Anesthesia was induced with thiamylal 5mg·kg^–1 and the trachea was intubated with succinylcholine 1mg·kg^–1, then anesthesia was maintained with 60% nitrous oxide in oxygen and sevolfurane, isoflurane or enflurane, depending on the group. Neuromuscular blocking effects were monitored by recording the electromyographic activity of the adductor pollicis muscle from supramaximal stimulation of the ulnar nerve at 10-s intervals. Pipecuronium 40µg·kg^–1 was administered when electromyographic activity had reached a stable state, 30min after succinylcholine administration. The maximum effect (% block of control) and clinical duration (time to 25% recovery) of pipecuronium were 99.1 ± 1.4% and 63.7 ± 14.7min (mean ± S.D.) for sevoflurane, 99.0 ± 2.0% and 60.9 ± 20.5min for isoflurane, and 98.0 ± 2.5% and 62.8 ± 28.7min for enflurane, respectively. There were no significant differences in these values between the anesthetics. Cardiovascular stimulant effects were not observed in any of the groups.We conclude that the effect of pipecuronium under seveflurane anesthesia is similar to that under isoflurane and enflurane anesthesia.(Nakao Y, Ohno M, Imai M, et al.: Neuromuscular effects of pipecuronium during sevoflurane anesthesia compared with isoflurane and enflurane anesthesia. J Anesth 7: 405--410, 1993)     

Bronchospasm during anesthesia in a patient with Pena-Shokeir syndrome

A 3-month-old boy with Pena-Shokeir syndrome underwent tracheotomy under general anesthesia. Patients with this syndrome may present anesthetic problems involving difficulties in tracheal intubation, possibilities of malignant hyperthermia, as well as perioperative respiratory complications related to hypoplasia of the lung. General anesthesia was induced and maintained with sevoflurane (2-3%) and nitrous oxide (0-50%) in oxygen (50-100%). The patient developed bronchospasm during tracheotomy. Atropine and epinephrine were administered intravenously and 5% sevoflurane was inhaled. The bronchospasm was improved gradually and surgery was successfully finished. Pena-Shokeir syndrome is an uncommon disease first reported by Pena & Shokeir in 1974 and characterized by congenital multiple arthrogryposis, characteristic facies, camptodactyly and pulmonary hypoplasia. In the perioperative management for a patient with Pena-Shokeir syndrome, special attention should be paid to abnormalities in the upper and lower respiratory systems, especially bronchospasm.     

静吸复合麻醉下小儿血中碳氧血红蛋白浓度的变化

目的 通过三种静吸复合麻醉条件下检测小儿血中碳氧血红蛋白(COHb)浓度的变化,评价其用于小儿的安全性。方法 行择期手术的患儿24例,根据使用吸入麻醉药及设置的新鲜气流量(FGF)的不同随机分为3组:Ⅰ组(地氟烷,500ml/min)、Ⅱ组(地氟烷,2000ml/min)和Ⅲ组(安氟烷,500ml/min),新鲜气流中O2:N2O为1:1。分别于机械通气前、后30、45、60min测定动脉血中COHb浓度,监测机械通气过程中各时点吸入麻醉药呼气末浓度(Cexp)、MAC等值。结果 (1)Ⅰ组和Ⅲ组:COHb在60min时点值高于其他时点值。Ⅱ组:COHb在45min时点值高于其他时点值。(2)Ⅰ组和Ⅱ组地氟烷Cexp分别为3.93％-4.24％、4.31％-4.43％,各时点相比差异无显著性(P>0.05);Ⅲ组安氟烷Cexp为0.87％-0.93％,与Ⅰ组相比各时点MAC值差异无显著性(P>0.05)。(3)Ⅰ组与Ⅱ组相比较、Ⅰ组与Ⅲ组相比较:各时点COHb浓度差异无显著性(P>0.05)。结论 含水量为6.08％以上的钠石灰、Cexp为0.87％～0.93％安氟烷或Cexp为3.93％～4.24％地氟烷(合并使用N2O)以及500ml/min FGF,这些条件可以安全地联合应用于机械通气在60min以内的小儿静吸复合麻醉;同样条件下,Cexp为4.31％-4.43％地氟烷和2000ml/min FGF同时应用于机械通气在60min以内的小儿静吸复合麻醉是安全的。     

美维松临床肌松效应和安全性的评价

目的：研究在安氟醚麻醉下，使用美维松的肌松效应和心血管反应并了解其副作用。方法：使用肌松监测仪监测ＴＯＦ（四个成串刺激）变化，观察在全麻下的３０例择期手术病人，使用美维松诱导插管时的最大肌松效应，术中微量泵泵入美维松维持肌松的有效剂量及停药后恢复指数，并了解其对电解质，肝肾功能的影响。结果：静脉注射美维松０．２ｍｇ／ｋｇ（３ＥＤ９５）后，在１１９±４．０秒获得最大阻滞及良好的气管插管条件，以５．８μｇ·ｋｇ－１·ｍｉｎ－１速度输入美维松可维持良好的肌肉阻滞，停药后恢复指数为９．９±４．０分钟，手术前后电解质，肝肾功能无明显变化。结论：美维松适用于诱导插管和短小手术的肌松维持，采用静脉输注也可满足中长手术的肌松需要。     

Sudden hypoxia during anesthesia in a patient with Kartagener's syndrome

We report a case of anesthesia in an adolescent with recurrent left pneumothorax, Kartagener's syndrome, and severe learning disability with behavioral difficulties. After induction of anesthesia, he rapidly developed severe desaturation as measured on pulse oximetry. Placement of an intercostal chest drain did not remedy the situation and he was found to have blocked the left main bronchus with viscous secretions. Subsequent suctioning relieved the obstruction. Despite successful postoperative thoracic epidural analgesia and minitracheostomy for bronchial toilet, he developed bronchopneumonia that resolved with antibiotics. We discuss anesthesia for patients with Kartagener's syndrome and for patients with pneumothorax.     

Dose-related cardiovascular effects of amrinone during enflurane anesthesia in the dog

The dose-related cardiovascular effects of amrinone, a synthetic cardiotonic and vasodilating drug, were investigated in dogs anesthetized with enflurane (2.2-2.4% end-tidal concentration). Twelve mongrel dogs were divided into two groups of six animals: an enflurane group (E) that received only enflurane, and an amrinone group (A). In the latter group each dog received the following sequential boluses and 30-min infusions: 1) the amrinone solvent alone; 2) amrinone, 1 mg/kg + 5 micrograms X kg-1 X min-1; 3) amrinone, 2 mg/kg + 10 micrograms X kg-1 X min-1; 4) amrinone, 4 mg/kg + 20 micrograms X kg-1 X min-1. Over the course of the experiment, 2.2-2.4% end-tidal enflurane alone resulted in a gradual decrease in cardiac index (CI), stroke volume index (SVI), and the maximum left ventricular dP/dt (LV dP/dtmax), without changes in heart rate (HR), mean arterial pressure (MAP), central venous pressure (CVP), or pulmonary capillary wedge pressure (PCWP) in group E. Significant differences from group E after 30 min of the lowest dose of amrinone included higher CI and SVI with lower systemic vascular resistance (SVR). The medium dose of amrinone, in addition to the effects already observed with the lowest dose of amrinone, decreased MAP and pulmonary vascular resistance (PVR), and increased LV dP/dtmax, when compared to group E only. Furthermore, the highest dose of amrinone caused lower pulmonary artery mean pressure (PAM), PCWP, and higher HR with shortened PR interval. The differences in MAP, CI, LV dP/dtmax, PCWP, PAM, PR interval, SVR, and PVR compared to E were still significant 30 min after the cessation of the highest dose. This study shows that the myocardial depressant effects of enflurane in an unstimulated canine model with a previously healthy heart can be overcome in a dose-related manner by amrinone. In contrast to other vasodilators, no reflex increase in plasma catecholamines was seen.(ABSTRACT TRUNCATED AT 250 WORDS)     

Serum inorganic fluoride levels in obese patients during and after enflurane anesthesia

Serum ionic fluoride levels in 24 markedly obese patients (127.6 +/- 6.0 kg) and seven nonobese control subjects (67.3 +/- 1.2 kg) were compared during and following enflurane anesthesia (less than 2.0 MAC hr). Peak serum fluoride levels were higher (28.0 +/- 1.9 vs 17.3 +/- 1.3 micrometers/L, p less than 0.01) and the rate at which fluoride levels increased was more rapid (slope 5.6 vs 2.5 micrometers/L/hr) in obese patients than in control patients. No clinical evidence of nephrotoxicity was found in either group. Vasopressin resistance tests were not performed, and thus it is inknown whether subclinical nephrotoxicity occurred in either study group. Possible reasons for increased enflurane metabolism in obesity are discussed. These possibilities include differences in fluoride ion kinetics, hepatic delivery and penetration of volatile anesthetics, and altered hepatic microsomal enzyme activity. Obesity rather than weight is an important determinant of anesthetic biotransformation.