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Time-frequency balanced spectral entropy of electroencephalogram (EEG) and frontal electromyogram (FEMG) is a novel measure of hypnosis during anesthesia. Two Entropy parameters are described: Response entropy (RE) is calculated from EEG and FEMG; and State Entropy (SE) is calculated mainly from EEG. This study was performed to validate their performance during transition from consciousness to unconsciousness under different anesthetic agents.Response entropy, SE [S/5 Entropy Module, M-ENTROPY (later in text: Entropy), Datex-Ohmeda Division, Instrumentarium Corp., Helsinki, Finland] and BIS (BIS XP, A-2000, Aspect Medical Systems, Newton, MA) data were collected from 70 patients; 30 anesthetized with propofol 2 mg kg-1, 20 with sevoflurane inhalation, and 20 with thiopental 5 mg kg-1. Loss and regaining of consciousness (LOC, ROC) was tested every 10 s, and sensitivity, specificity, and prediction probability (Pk) were calculated. Behavior of the indices was studied.Sensitivity, specificity, and Pk values for consciousness were high and similar for all indices. During regaining of consciousness after propofol bolus, RE, SE, and BIS values recovered by 81 +/- 22%, 75 +/- 26%, and 59 +/- 18% (mean +/- SD), respectively, from the minimum relative to their baseline. After thiopental bolus, RE, SE, and BIS values recovered by 86+/-21%, 88 +/- 13%, and 63 +/- 14%, respectively. The relative rise was higher in RE and SE compared with BIS (P0.01). During deep levels of hypnosis, RE and SE decreased monotonously as a function of burst suppression ratio, while BIS showed biphasic behavior. On average, RE indicated emergence from anesthesia 11 s earlier than SE, and 12.4 s earlier than BIS.All indices, RE, SE, and BIS, distinguished excellently between conscious and unconscious states during propofol, sevoflurane, and thiopental anesthesia. During burst suppression, Entropy parameters RE and SE, but not BIS, behave monotonously. During regaining of consciousness after a thiopental or propofol bolus, RE and SE values recovered significantly closer to their baseline values than did BIS. Response entropy indicates emergence from anesthesia earlier than SE or BIS.

Increasing numbers of individuals leading normal lives have transplanted organs. They may appear in any hospital for treatment of trauma or general diseases. Common anaesthesia methods can be used for these patients, but safe conduct of anaesthesia requires knowledge of the immunosuppression, risk factors, and altered physiology or drug actions. This article reviews the anaesthesia-related literature on patients with transplanted organs.

Background: The use of N2O during low-flow anesthesia (LFA) causes difficulty in predicting inspired gas mixtures and oxygen concentration due to accumulation. An alternative technique, which uses a mixture of oxygen and air and a morphine infusion to replace N2O, has been evaluated in children during LFA, and the clinical effects and composition of gases in the system are presented here. Methods: Thirty-five children aged 2-13 years undergoing major urogenital surgery were recruited into the study. Following a standardized induction, anesthesia was maintained with 2% sevoflurane in combination with a morphine infusion. After induction with 4 l min(-1), flow rates were reduced to 2 l min(-1) and finally to 1 l min(-1) at 10 min (0.5 l oxygen + 0.5 l air). The delivered oxygen concentration, oxygen saturation and the inspired and expired O-2, sevoflurane and CO2 concentrations were recorded from the start of induction to the end of anesthesia. Results: The duration of LFA was 132 +/- 89 min. The concentrat-ion of oxygen delivered by the flow meters during this period was 55-60%. Although the changes in inspired and expired oxygen and sevoflurane and inspired CO2 related to the duration of LFA were statistically significant (P < 0.0001), they were not clinically relevant. All vital parameters were stable. Four patients required supplemental morphine and nine presented emergence agitation. Conclusions: We concluded that an N2O-free LFA technique with 0.5 l min(-1) of air and 0.51 min(-1) of O-2 supplemented by sevoflurane and a morphine infusion is safe and effective in children. The resulting high-inspired oxygen concentration prevents occurrence of hypoxic gas mixtures, and the use of supplemental morphine compensates for the absence of N2O and overcomes the possibility of light anesthesia arising from a decrease in the inspired sevoflurane concentration. C1 Istanbul Univ, Cesrahpasa Med Fac, Dept Anesthesiol & Reanimat, TR-34098 Istanbul, Turkey. Bakirkoy Municipal Hosp, Istanbul, Turkey. Pamukkale Univ, Dept Anesthesiol & Reanimat, Denizli, Turkey.

Background: Autoregressive modelling with exogenous input of the middle-latency auditory evoked potential has been developed for monitoring of anaesthetic depth. This study was designed to investigate the dose–response relationship between endtidal desflurane concentrations and the Alaris Autoregressive Index (AAI, Alaris Medical, Hampshire, UK, version 1.4) or the bispectral index (Aspect Medical Systems, Newton, MA, USA, version XP). Methods: Twenty-one patients scheduled for radical prostatectomy were investigated. After premedication and induction of anaesthesia with propofol und remifentanil all patients received atracurium and a remifentanil background infusion at a constant rate of 0.1 µg kg−1 min−1. During dissection of the prostate, desflurane endtidal concentrations were varied between 3 and 9 vol%. Both AAI and BIS were determined and compared with the respective endtidal desflurane concentration. Results: None of the patients showed a significant change of AAI values while changing the desflurane concentrations between 3 and 9 vol%. The dose–response of BIS values and desflurane concentrations was not uniform: two patients showed increasing BIS values with increasing desflurane concentrations, while in three patients BIS values remained unchanged. In 16 patients decreasing BIS values adequately reflected an increase in desflurane concentrations. Conclusion: Changes of desflurane concentrations during deep anaesthesia were adequately displayed only in 16 of 21 cases by BIS but in none of the cases by AAI monitoring.