BACKGROUND: The aim of this study is to control the depth, the quality of recovery of total inhalation isoflurane anesthesia with or without nitrous oxide. DESIGN: Controlled comparative study was carried out on 51 patients, aged 40-54 yr, ASA 1, undergoing saphenectomy, in an University Clinic. METHODS: Induction: thiopental (3.5 mg kg), atracurium (0.6 mg kg) i.v. Patients were randomly assigned to: group 1 (26 patients), 5% isoflurane in air, by mask; group 2 (25 patients), 3% isoflurane and 60% N2O, by mask.
OBJECTIVE: To compare the hemodynamic stability and time to recovery of consciousness after long-duration (> 3 h) neurosurgery with 2 anesthetic protocols: total intravenous anesthesia with propofol as the single hypnotic agent and inhalational anesthesia with isoflurane. PATIENTS AND METHOD: We studied 58 middle-aged patients (range 40-50 years) scheduled for intracranial surgery. The patients, who all scored over 13 on the Glasgow coma scale before surgery, were randomly divided into two groups: 27 in group I received isoflurane and 31 in group II received propofol.
Whether anesthetized patients register emotionally charged information remains controversial. We tested this possibility using subanesthetic concentrations of propofol or desflurane. Twenty-two volunteers (selected for hypnosis susceptibility) received propofol and desflurane (on separate occasions, and in a random order) at a concentration 1.5-2 times each individual's minimum alveolar anesthetic concentration (MAC)-awake (or equivalent for propofol).
Using the Stephens anaesthetic apparatus-which is a closed system with an in-circuit, nonprecision vaporizer-and isoflurane as anaesthetic gas, 18 rabbits were anaesthetized and showed sufficient hypnosis, analgesia, and muscle relaxation during bone surgery. Induction of anaesthesia was achieved with intravenous propofol and all rabbits were intubated afterwards.
The bispectral index (BIS) is derived empirically from the electroencephalogram database of patients receiving common anaesthetics, but it may not be valid for uncommon agents. Therefore, we investigated how xenon affects the BIS. Nine and 11 patients were anaesthetized with 0.8 of the minimal alveolar concentration (MAC) of isoflurane (0.92%) and xenon (56%), respectively. After the end of operation, these concentrations were decreased in decrements of 0.1 MAC (isoflurane 0.12% or xenon 7%) and each new concentration was maintained for 15 min.
BACKGROUND: Nitrous oxide (N2O) has been suggested to contribute to bowel distension, resulting in worsened operating conditions for laparoscopic surgery, and to increase incidence of postoperative nausea and vomiting. Therefore, our objective was to assess the feasibility of two remifentanil-based anaesthetic regimens free from N2O with special regard to recovery profile, postoperative analgesic demand and side effects in patients undergoing laparoscopic cholecystectomy.
A model-based closed-loop control system is presented to regulate hypnosis with the volatile anesthetic isoflurane. Hypnosis is assessed by means of the bispectral index (BIS), a processed parameter derived from the electroencephalogram. Isoflurane is administered through a closed-circuit respiratory system. The model for control was identified on a population of 20 healthy volunteers. It consists of three parts: a model for the respiratory system, a pharmacokinetic model and a pharmacodynamic model to predict BIS at the effect compartment. A cascaded internal model controller is employed.
We evaluated the cognitive recovery profiles in elderly patients after general anesthesia with desflurane or sevoflurane. After IRB approval, 70 ASA physical status I-III consenting elderly patients (> or =65 yr old) undergoing total knee or hip replacement procedures were randomly assigned to one of two general anesthetic groups. Propofol and fentanyl were administered for induction of anesthesia, followed by either desflurane 2%-4% or sevoflurane 1%-1.5% with nitrous oxide 65% in oxygen. The desflurane (2.5 +/- 0.6 MAC. h) and sevoflurane (2.7 +/- 0.5 MAC.
BACKGROUND: Neuronal nicotinic acetylcholine receptors (nAChRs) have been implicated in the mechanism of action of isoflurane as they are inhibited at subanesthetic concentrations. Despite clear evidence for nicotinic inhibition at relevant isoflurane concentrations, it is unclear what behavioral result ensues, if any. METHODS: The authors have modeled two behaviors common to all general anesthetics, immobility and hypnosis, as minimum alveolar concentration that prevents movement in response to a supramaximal stimulus (MAC) and loss of righting reflex (LORR).
OBJECTIVE: [corrected] As indicated by the manufacturer the EEG monitor Narcotrend trade mark (MonitorTechnik, Bad Bramstedt) can be used to analyse EEG effects of volatile anaesthetics, however, published data are missing. This study evaluated the emergence from a desflurane/remifentanil anaesthetic and was designed to investigate the relationship between Narcotrend stages (version 2.0 AF) and end-tidal desflurane concentrations and to identify the pattern of changes of the Narcotrend stages during recovery.