No abstract available.
Electroencephalography* ; Intraoperative Awareness*

No abstract available.
Anesthesia, General* ; Delirium* ; Intraoperative Awareness* ; Memory* ; Midazolam*

The Selectatec mounting system was devised to provide easy and quick on-site fitting of various vaporizers for the anesthetic machine. However, a quick changing system for the vaporizer can also damage the O-ring due to friction between the vaporizer and the Selectatec back bar. We herein report a case of an unexpected anesthetic gas leakage from a damaged O-ring on the Selectatec back bar, which resulted from exchanging the vaporizers between two operations. In cases using the Datex Ohmeda machine, it is not easy to detect leakages from the vaporizers because of the location of the check valve near to the fresh gas outlet. This complicates the use of the positive pressure leakage test to detect a low pressure system leakage on the Selectatec back bar. We recommend the preanesthetic negative pressure or low-flow leakage test to detect a low pressure leakage when exchanging vaporizers on the Selectatec system.
Friction ; Intraoperative Awareness ; Nebulizers and Vaporizers ; Ventilators, Mechanical

BACKGROUND: Process dissociation procedure has been used to evaluate explicit and implicit memories. Two process-dissociation measurement models are described. METHODS: This prospective study evaluated intraoperative memory formation in Korean patients undergoing elective surgery under general anesthesia and its relation to the depth of hypnotic state. A total of 270 patients enrolled were randomly assigned to three groups based on Bispectral Index (BIS) values in the following ranges: 30 to 40, BIS 40 to 50, and BIS 50 to 60 according to the level of hypnotic depth induced by propofol or sevoflurane during the presentation of wordlists. When the level of hypnotic depth was maintained at the target BIS range, words were played for 15 minutes via headphones to patients. Within 24 hours after the word presentation, memory was assessed using an auditory word stem completion test. The probability of explicit and implicit memory was calculated using original and extended measurement models. Brice interviews were performed within 1 and 24 hours after surgery. RESULTS: A total of 119 patients who did not deviate from the target BIS range were included in the analysis. The 95% confidence interval (CI) of the probability of occurrence of implicit memory evaluated by the original model did not include zero. However, when the extension model was used, 0 was included in the 95% CI. Explicit memory evaluated via Brice interviews did not occur in any group. CONCLUSIONS: When BIS was maintained in the range of 30 to 60 during surgery, no explicit or implicit memory was observed.
Anesthesia ; Anesthesia, General ; Humans ; Intraoperative Awareness ; Memory* ; Propofol ; Prospective Studies

Currently, anesthesiologists use clinical parameters to directly measure the depth of anesthesia (DoA). This clinical standard of monitoring is often combined with brain monitoring for better assessment of the hypnotic component of anesthesia. Brain monitoring devices provide indices allowing for an immediate assessment of the impact of anesthetics on consciousness. However, questions remain regarding the mechanisms underpinning these indices of hypnosis. By briefly describing current knowledge of the brain's electrical activity during general anesthesia, as well as the operating principles of DoA monitors, the aim of this work is to simplify our understanding of the mathematical processes that allow for translation of complex patterns of brain electrical activity into dimensionless indices. This is a challenging task because mathematical concepts appear remote from clinical practice. Moreover, most DoA algorithms are proprietary algorithms and the difficulty of exploring the inner workings of mathematical models represents an obstacle to accurate simplification. The limitations of current DoA monitors - and the possibility for improvement - as well as perspectives on brain monitoring derived from recent research on corticocortical connectivity and communication are also discussed.
Anesthesia* ; Anesthesia, General ; Anesthetics ; Brain* ; Consciousness ; Electroencephalography ; Hypnosis ; Intraoperative Awareness ; Intraoperative Neurophysiological Monitoring ; Mathematical Concepts ; Models, Theoretical

Balanced anesthesia is being equilibrated with the maintenance of light planes of anesthesia and the relatively free utilization of muscle relaxants to prevent untoward movement of the patient in response to surgical stimuli. However, muscle relaxants per se do not contributes to the state of hypnosis or analgesia. Therfore, awareness during modern anesthesia must be seriously taken. We have given anesthesia in 175 cases for cesarean section in order to investigate intraoperative awareness. Among the 175 anesthetic cases, 13 cases had awareness of pain and 19 cases had auditor awareness. Accordingly the total incidence of awareness in our investigation was 16% which was significantly high and should be considered in clinical anesthesia practice.
Analgesia ; Anesthesia* ; Balanced Anesthesia ; Cesarean Section* ; Female ; Humans ; Hypnosis ; Incidence ; Intraoperative Awareness ; Pregnancy

BACKGROUND: Patient awareness is a particular problem in cardiac anesthesia with cardiopulmonary bypass (CPB). Transformed electroencephalogram monitors, such as the Bispectral index (BIS) monitor, has been advocated as a tool that may reduce the incidence of unexpected intraoperative recall. The authors studied the effects of hypothermia during CPB on the BIS score and the BIS can be a useful monitor to measure anesthetic depth and requirement during hypothermic CPB. METHODS: Eighteen consenting volunteers scheduled for an elective cardiac surgery were studied. Volunteers were randomly allocated to one of two groups. All patients were given propofol by a target controlled infusion system, Diprifusor, with fentanyl (0.6 ug/kg/min). In group A, before and during CPB propofol was infused at a predetermined target plasma concentration (2.0 ug/ml), the BIS score and temperature were monitored. In group B, before and during CPB, to maintain the BIS score at 30 40 units, changing propofol plasma concentrations and temperature were monitored. Then we asked patients about intraoperative awareness. RESULTS: In group A, compared with before the start of CPB, the BIS score was decreased by the temperature (P < 0.05) during CPB (5 min, 10 min, 20 min, 30 min after the start of CPB) and after the stop of CPB. In group B, compared with before the start of CPB, the required propofol plasma concentration was decreased by the temperature during CPB (P < 0.05). In addition, no one experienced awareness during surgery. CONCLUSIONS: The BIS score was decreased by a decline in temperature during the hypothermic CPB, and bispectral analysis can be a relative indicator of anesthetic requirement and the hypnotic state under this conception.
Anesthesia ; Cardiopulmonary Bypass* ; Electroencephalography ; Fentanyl ; Fertilization ; Humans ; Hypothermia ; Incidence ; Intraoperative Awareness ; Plasma ; Propofol ; Thoracic Surgery ; Volunteers

We report a case of unintentional intraoperative awareness during sevoflurane-remifentanil anesthesia in a 26 years old woman undergoing elective minimal invasive mitral valvuloplasty. Cardioprotective effects of sevoflurane were clinically most apparent when administered throughout the surgical procedure. Also use of sevoflurane during cardiopulmonary bypass decreases incidence of awareness. Although awareness during cardiac anesthesia has been previously described with sevoflurane, the implication of this case is that unexpected awareness can occur in patients with sevoflurane during cardiopulmonary bypass on cardiac surgery. Therefore, more attention is needed to use sevoflurane during cardiopulmonary bypass.
Anesthesia ; Cardiopulmonary Bypass ; Female ; Humans ; Incidence ; Intraoperative Awareness ; Methyl Ethers ; Piperidines ; Thoracic Surgery

A 24-year-old woman underwent endoscopic thyroidectomy with total intravenous anesthesia technique. Immediately after surgery, she said that she had experienced intraoperative awareness for a while. She had vague auditory recall and some degree of pain at the incision site. She was given adequate doses of anesthetics during the operation and the drug delivery system was not compromised. We report awareness during total intravenous anesthesia for endoscopic thyroidectomy.
Anesthesia, Intravenous ; Anesthetics ; Drug Delivery Systems ; Female ; Humans ; Intraoperative Awareness ; Thyroidectomy ; Young Adult

BACKGROUND: Bispectral index (BIS) monitoring reduces the cases of intraoperative awareness. Several factors can alter BIS readings without affecting the depth of anesthesia. We conducted a study to assess the impact of beach chair position (sitting position) on BIS readings. METHODS: General anesthesia was administered to 30 patients undergoing arthroscopic shoulder surgery. Patients were kept in neutral position (supine) for 10 minutes and BIS readings, mean arterial blood pressure, heart rate, end-tidal carbon dioxide, and end-tidal sevoflurane were recorded. Patients were then shifted to beach chair position. After 15 minutes, data were recorded. RESULTS: A significant decrease in BIS values (P < 0.01) associated with a position change from neutral position to beach chair position was evident. CONCLUSIONS: BIS values are significantly decreased in the beach chair position compared with the neutral position and might affect interpretation of the depth of anesthesia.
Anesthesia ; Anesthesia, General ; Arterial Pressure ; Carbon Dioxide ; Heart Rate ; Humans ; Intraoperative Awareness ; Reading ; Shoulder*