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S W Henneberg - One of the best experts on this subject based on the ideXlab platform.
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Depth of Anaesthesia monitoring in obese patients: a randomized study of propofol–remifentanil
Acta anaesthesiologica Scandinavica, 2009Co-Authors: Christian S. Meyhoff, S W Henneberg, B. G. Jørgensen, M. R. Gätke, Lars S. RasmussenAbstract:Background: In obese patients, Depth of Anaesthesia monitoring could be useful in titrating intravenous anaesthetics. We hypothesized that Depth of Anaesthesia monitoring would reduce recovery time and use of anaesthetics in obese patients receiving propofol and remifentanil. Methods: We investigated 38 patients with a body mass index ≥30 kg/m2 scheduled for an abdominal hysterectomy. Patients were randomized to either titration of propofol and remifentanil according to a cerebral state monitor (CSM group) or according to usual clinical criteria (control group). The primary end point was time to eye opening and this was assessed by a blinded observer. Results: Time to eye opening was 11.8 min in the CSM group vs. 13.4 min in the control group (P=0.58). The average infusion rate for propofol was a median of 516 vs. 617 mg/h (P=0.24) and for remifentanil 2393 vs. 2708 μg/h (P=0.04). During surgery, when the cerebral state index was continuously between 40 and 60, the corresponding optimal propofol infusion rate was 10 mg/kg/h based on ideal body weight. Conclusion: No significant reduction in time to eye opening could be demonstrated when a CSM was used to titrate propofol and remifentanil in obese patients undergoing a hysterectomy. A significant reduction in remifentanil consumption was found.
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peroperative Depth of Anaesthesia may influence postoperative opioid requirements
Acta Anaesthesiologica Scandinavica, 2005Co-Authors: S W Henneberg, D Rosenborg, Weber E Jensen, P Ahn, B Burgdorff, L L ThomsenAbstract:Background: Studies on monitoring the Depth of Anaesthesia have shown that with the use of these monitors the peroperative consumption of anaesthetics can be reduced. Studies have also indicated that the peroperative Depth of Anaesthesia may affect the postoperative course. The purpose of this study was to evaluate a possible relation between the Depths of Anaesthesia and the postoperative pain score and consumption of morphine. Methods: We used middle latency auditory evoked potentials (MLAEPs) for monitoring the Depth of Anaesthesia. The study was prospective, observer blinded and included 50 women scheduled for elective abdominal hysterectomy. Anaesthesia was induced using propofol and remifentanil. Before leaving the recovery room the patients were provided with a programmed patient-controlled pump (PCA), which was only activated on demand. Auditory evoked potentials were registered from just before induction of Anaesthesia and during the whole procedure, but the anaesthetist did not have access to the monitor. Results: Fifty patients were included and seven were excluded. The remaining 43 patients were divided into two groups: Group High (n=12) with an AAI>28 for >5% of the registration time and Group Low (n=31) with an AAI>28 for <5% of the registration time. Group High had significantly higher morphine requirements in the recovery and activated the PCA-pump more frequently during the first 24 postoperative hours. Conclusion: The results indicate that the peroperative Depth of Anaesthesia may have effects on the postoperative analgesic requirements.
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Peroperative Depth of Anaesthesia may influence postoperative opioid requirements
Acta anaesthesiologica Scandinavica, 2005Co-Authors: S W Henneberg, D Rosenborg, P Ahn, B Burgdorff, E. Weber Jensen, L L ThomsenAbstract:Background: Studies on monitoring the Depth of Anaesthesia have shown that with the use of these monitors the peroperative consumption of anaesthetics can be reduced. Studies have also indicated that the peroperative Depth of Anaesthesia may affect the postoperative course. The purpose of this study was to evaluate a possible relation between the Depths of Anaesthesia and the postoperative pain score and consumption of morphine. Methods: We used middle latency auditory evoked potentials (MLAEPs) for monitoring the Depth of Anaesthesia. The study was prospective, observer blinded and included 50 women scheduled for elective abdominal hysterectomy. Anaesthesia was induced using propofol and remifentanil. Before leaving the recovery room the patients were provided with a programmed patient-controlled pump (PCA), which was only activated on demand. Auditory evoked potentials were registered from just before induction of Anaesthesia and during the whole procedure, but the anaesthetist did not have access to the monitor. Results: Fifty patients were included and seven were excluded. The remaining 43 patients were divided into two groups: Group High (n=12) with an AAI>28 for >5% of the registration time and Group Low (n=31) with an AAI>28 for
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On-line analysis of middle latency auditory evoked potentials (MLAEP) for monitoring Depth of Anaesthesia in laboratory rats.
Medical engineering & physics, 1998Co-Authors: Erik Weber Jensen, Marianne Nygaard, S W HennebergAbstract:Abstract In laboratory animals as well as in human beings a Depth of Anaesthesia, where the subject has no pain or recall of events from the surgery, should be provided. Haemodynamic parameters such as heart rate and blood pressure are not a guarantee for an optimal Depth of Anaesthesia, especially when using neuromuscular blocking agents (NMBA). A number of studies suggest that the Middle Latency Auditory Evoked Potentials (MLAEP) contain information about the state of consciousness in humans. The purpose of this study was to examine whether the AEP could serve as an indicator of Depth of Anaesthesia in rats. The AEP was elicited with a click stimulus and monitored in an 80 ms window synchronised to the stimulus. The AEP was extracted applying an Auto Regressive Model with Exogenous Input (ARX-model) from which a Depth of Anaesthesia Index (DAI) was calculated. DAI was normalised to 100 while awake and decreasing gradually to a level between 50 and 20 as the rat was anaesthetised. Nine rats were anaesthetised and included in the study. Four doses of Hypnorm vet.® and Dormicum® were given as a total, each with 5 minutes interval. Clinical signs of the level of Anaesthesia were observed simultaneously with the AEP. The results showed that in four rats DAI decreased to a level below 30 while anaesthetised. In the remaining five rats the AEP was only decreased to a level below 45. The results indicated that a simple dosing regimen based on weight was unable to give the same Depth of Anaesthesia in individual rats. The decrease in the DAI correlated well with the loss of stimulus response. In conclusion, MLAEP could be used as an indicator of Depth of Anaesthesia in rats during Hypnorm vet.® and Dormicum® administration. However studies applying other anaesthetic drugs should be carried out, before a conclusion of the general utility of the method can be made.
Lars S. Rasmussen - One of the best experts on this subject based on the ideXlab platform.
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Depth of Anaesthesia and post-operative cognitive dysfunction.
Acta anaesthesiologica Scandinavica, 2009Co-Authors: Jacob Steinmetz, Kamilia S. Funder, Benny Dahl, Lars S. RasmussenAbstract:Background: A deep level of Anaesthesia measured by the bispectral index has been found to improve processing speed as one aspect of cognitive function after surgery. The purpose of the present study was to assess the possible effect of the level of Anaesthesia on post-operative cognitive dysfunction (POCD) 1 week after surgery, as assessed by a neuropsychological test battery. Methods: We included 70 patients >60 years of age scheduled for elective non-cardiac surgery with general Anaesthesia. The Depth of Anaesthesia was monitored using the cerebral state monitor, which provided a cerebral state index (CSI) value. Cognitive function was assessed by the ISPOCD neuropsychological test battery before and at 1 week (or hospital discharge) after surgery and POCD was defined as a Z score above 1.96. Results: Five patients were not assessed after surgery. The mean CSI was 40 and 43 in patients with (N=9) and without POCD (N=56), respectively (P=0.41). The cumulated time of both deep Anaesthesia (CSI 60) did not differ significantly, and no significant correlation was found between the mean CSI and the Z score. Conclusion: We were unable to detect a significant association between the Depth of Anaesthesia and the presence of POCD 1 week after the surgery.
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Depth of Anaesthesia monitoring in obese patients a randomized study of propofol remifentanil
Acta Anaesthesiologica Scandinavica, 2009Co-Authors: Christian S. Meyhoff, S W Henneberg, B. G. Jørgensen, M. R. Gätke, Lars S. RasmussenAbstract:Background: In obese patients, Depth of Anaesthesia monitoring could be useful in titrating intravenous anaesthetics. We hypothesized that Depth of Anaesthesia monitoring would reduce recovery time and use of anaesthetics in obese patients receiving propofol and remifentanil. Methods: We investigated 38 patients with a body mass index ≥30 kg/m2 scheduled for an abdominal hysterectomy. Patients were randomized to either titration of propofol and remifentanil according to a cerebral state monitor (CSM group) or according to usual clinical criteria (control group). The primary end point was time to eye opening and this was assessed by a blinded observer. Results: Time to eye opening was 11.8 min in the CSM group vs. 13.4 min in the control group (P=0.58). The average infusion rate for propofol was a median of 516 vs. 617 mg/h (P=0.24) and for remifentanil 2393 vs. 2708 μg/h (P=0.04). During surgery, when the cerebral state index was continuously between 40 and 60, the corresponding optimal propofol infusion rate was 10 mg/kg/h based on ideal body weight. Conclusion: No significant reduction in time to eye opening could be demonstrated when a CSM was used to titrate propofol and remifentanil in obese patients undergoing a hysterectomy. A significant reduction in remifentanil consumption was found.
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Depth of Anaesthesia monitoring in obese patients: a randomized study of propofol–remifentanil
Acta anaesthesiologica Scandinavica, 2009Co-Authors: Christian S. Meyhoff, S W Henneberg, B. G. Jørgensen, M. R. Gätke, Lars S. RasmussenAbstract:Background: In obese patients, Depth of Anaesthesia monitoring could be useful in titrating intravenous anaesthetics. We hypothesized that Depth of Anaesthesia monitoring would reduce recovery time and use of anaesthetics in obese patients receiving propofol and remifentanil. Methods: We investigated 38 patients with a body mass index ≥30 kg/m2 scheduled for an abdominal hysterectomy. Patients were randomized to either titration of propofol and remifentanil according to a cerebral state monitor (CSM group) or according to usual clinical criteria (control group). The primary end point was time to eye opening and this was assessed by a blinded observer. Results: Time to eye opening was 11.8 min in the CSM group vs. 13.4 min in the control group (P=0.58). The average infusion rate for propofol was a median of 516 vs. 617 mg/h (P=0.24) and for remifentanil 2393 vs. 2708 μg/h (P=0.04). During surgery, when the cerebral state index was continuously between 40 and 60, the corresponding optimal propofol infusion rate was 10 mg/kg/h based on ideal body weight. Conclusion: No significant reduction in time to eye opening could be demonstrated when a CSM was used to titrate propofol and remifentanil in obese patients undergoing a hysterectomy. A significant reduction in remifentanil consumption was found.
L L Thomsen - One of the best experts on this subject based on the ideXlab platform.
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peroperative Depth of Anaesthesia may influence postoperative opioid requirements
Acta Anaesthesiologica Scandinavica, 2005Co-Authors: S W Henneberg, D Rosenborg, Weber E Jensen, P Ahn, B Burgdorff, L L ThomsenAbstract:Background: Studies on monitoring the Depth of Anaesthesia have shown that with the use of these monitors the peroperative consumption of anaesthetics can be reduced. Studies have also indicated that the peroperative Depth of Anaesthesia may affect the postoperative course. The purpose of this study was to evaluate a possible relation between the Depths of Anaesthesia and the postoperative pain score and consumption of morphine. Methods: We used middle latency auditory evoked potentials (MLAEPs) for monitoring the Depth of Anaesthesia. The study was prospective, observer blinded and included 50 women scheduled for elective abdominal hysterectomy. Anaesthesia was induced using propofol and remifentanil. Before leaving the recovery room the patients were provided with a programmed patient-controlled pump (PCA), which was only activated on demand. Auditory evoked potentials were registered from just before induction of Anaesthesia and during the whole procedure, but the anaesthetist did not have access to the monitor. Results: Fifty patients were included and seven were excluded. The remaining 43 patients were divided into two groups: Group High (n=12) with an AAI>28 for >5% of the registration time and Group Low (n=31) with an AAI>28 for <5% of the registration time. Group High had significantly higher morphine requirements in the recovery and activated the PCA-pump more frequently during the first 24 postoperative hours. Conclusion: The results indicate that the peroperative Depth of Anaesthesia may have effects on the postoperative analgesic requirements.
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Peroperative Depth of Anaesthesia may influence postoperative opioid requirements
Acta anaesthesiologica Scandinavica, 2005Co-Authors: S W Henneberg, D Rosenborg, P Ahn, B Burgdorff, E. Weber Jensen, L L ThomsenAbstract:Background: Studies on monitoring the Depth of Anaesthesia have shown that with the use of these monitors the peroperative consumption of anaesthetics can be reduced. Studies have also indicated that the peroperative Depth of Anaesthesia may affect the postoperative course. The purpose of this study was to evaluate a possible relation between the Depths of Anaesthesia and the postoperative pain score and consumption of morphine. Methods: We used middle latency auditory evoked potentials (MLAEPs) for monitoring the Depth of Anaesthesia. The study was prospective, observer blinded and included 50 women scheduled for elective abdominal hysterectomy. Anaesthesia was induced using propofol and remifentanil. Before leaving the recovery room the patients were provided with a programmed patient-controlled pump (PCA), which was only activated on demand. Auditory evoked potentials were registered from just before induction of Anaesthesia and during the whole procedure, but the anaesthetist did not have access to the monitor. Results: Fifty patients were included and seven were excluded. The remaining 43 patients were divided into two groups: Group High (n=12) with an AAI>28 for >5% of the registration time and Group Low (n=31) with an AAI>28 for
R. Hofmockel - One of the best experts on this subject based on the ideXlab platform.
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clinical evaluation of a simultaneous closed loop Anaesthesia control system for Depth of Anaesthesia and neuromuscular blockade
Anaesthesia, 2011Co-Authors: M. Janda, Olaf Simanski, B. Pohl, J. Bajorat, Gabriele Noeldgeschomburg, R. HofmockelAbstract:Summary We developed a closed-loop system to control the Depth of Anaesthesia and neuromuscular blockade using the bispectral index and the electromyogram simultaneously and evaluated the clinical performance of this combined system for general Anaesthesia. Twenty-two adult patients were included in this study. Anaesthesia was induced by a continuous infusion of remifentanil at 0.4 μg.kg−1.min−1 (induction dose) and then 0.25 μg.kg−1.min−1 (maintenance dose) and propofol at 2 mg.kg−1 3 min later. The combined automatic control was started 2 min after tracheal intubation. The Depth of Anaesthesia was recorded using bispectral index monitoring using a target value of 40. The target value of neuromuscular blockade, using mivacurium, was a T1/T10 twitch height of 10%. The precision of the system was calculated using internationally defined performance parameters. Twenty patients were included in the data analysis. The mean (SD) duration of simultaneous control was 129 (69) min. No human intervention was necessary during the computer-controlled administration of propofol and mivacurium. All patients assessed the quality of Anaesthesia as ‘good’ to ‘very good’; there were no episodes of awareness. The mean (SD) median performance error, median absolute performance error and wobble for the control of Depth of Anaesthesia and for neuromuscular blockade were −0.31 (1.78), 6.76 (3.45), 6.32 (2.93) and −0.38 (1.68), 3.75 (4.83), 3.63 (4.69), respectively. The simultaneous closed-loop system using propofol and mivacurium was able to maintain the target values with a high level of precision in a clinical setting. You can respond to this article at http://www.Anaesthesiacorrespondence.com
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Clinical evaluation of a simultaneous closed‐loop Anaesthesia control system for Depth of Anaesthesia and neuromuscular blockade*
Anaesthesia, 2011Co-Authors: M. Janda, Olaf Simanski, B. Pohl, J. Bajorat, Gabriele Noeldge-schomburg, R. HofmockelAbstract:Summary We developed a closed-loop system to control the Depth of Anaesthesia and neuromuscular blockade using the bispectral index and the electromyogram simultaneously and evaluated the clinical performance of this combined system for general Anaesthesia. Twenty-two adult patients were included in this study. Anaesthesia was induced by a continuous infusion of remifentanil at 0.4 μg.kg−1.min−1 (induction dose) and then 0.25 μg.kg−1.min−1 (maintenance dose) and propofol at 2 mg.kg−1 3 min later. The combined automatic control was started 2 min after tracheal intubation. The Depth of Anaesthesia was recorded using bispectral index monitoring using a target value of 40. The target value of neuromuscular blockade, using mivacurium, was a T1/T10 twitch height of 10%. The precision of the system was calculated using internationally defined performance parameters. Twenty patients were included in the data analysis. The mean (SD) duration of simultaneous control was 129 (69) min. No human intervention was necessary during the computer-controlled administration of propofol and mivacurium. All patients assessed the quality of Anaesthesia as ‘good’ to ‘very good’; there were no episodes of awareness. The mean (SD) median performance error, median absolute performance error and wobble for the control of Depth of Anaesthesia and for neuromuscular blockade were −0.31 (1.78), 6.76 (3.45), 6.32 (2.93) and −0.38 (1.68), 3.75 (4.83), 3.63 (4.69), respectively. The simultaneous closed-loop system using propofol and mivacurium was able to maintain the target values with a high level of precision in a clinical setting. You can respond to this article at http://www.Anaesthesiacorrespondence.com
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Depth of Anaesthesia during intubation: comparison between propofol and thiopentone
Der Anaesthesist, 2006Co-Authors: C. E. Beck, B. Pohl, M. Janda, J. Bajorat, R. HofmockelAbstract:In order to study the Depth of Anaesthesia during endotracheal intubation, 30 patients received either thiopentone or propofol for Anaesthesia induction. The BIS value as a parameter for the Depth of Anaesthesia and the rate pressure product (RPP) were acquired online. Patients who received thiopentone for Anaesthesia induction showed significantly higher BIS values at the moment of intubation and reached BIS values >60 significantly more frequently than patients receiving propofol. The RPP in the propofol group lay significantly below that of the thiopentone patients. For all patients there was an mean increase in BIS values of 8 index points and an increase in the RPP. Therefore, BIS values around 50 should be achieved before intubation in order to avoid the critical BIS value for awareness of >60 despite the increase caused by the intubation procedure. Within 24 h of intubation all patients were interviewed for possible signs of awareness. None of the patients was able to remember the intubation or reported other experiences that indicated an unconscious awareness. Nevertheless, the progress of BIS values in a standardized intubation as performed in the normal clinical routine, shows that the use of thiopentone for initiating Anaesthesia results in a very flat level of Anaesthesia during intubation. The risk for patients to experience awareness should therefore, not be underestimated. Therefore, when using thiopentone it is recommended to also use a rapid acting muscle relaxant or to select a high ED95 to compensate for the flat level of Anaesthesia. Alternatively, repetetive boluses of the hypnotic shortly before intubation should be considered or to revert to propofol. The dosage and pharmacokinetics of the analgesic should also be taken into consideration because an insufficient analgesia leads to a faster flattening of the Depth of Anaesthesia.
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Measurement and control of neuromuscular blockade and Depth of Anaesthesia
2003 European Control Conference (ECC), 2003Co-Authors: Olaf Simanski, R. Kähler, B. Pohl, R. Hofmockel, R. Friedrich, Bernhard P. LampeAbstract:The paper considers control problems for neuromuscular blockade and Depth of Anaesthesia. The control system is intended to be used in controlling the main parts of general Anaesthesia. The applied measurement techniques, experimental conditions and control strategies are presented. The results of a study with 31 patients for the control of neuromuscular blockade, and first trials for 6 patients for the control of Depth of Anaesthesia are listed.
Olaf Simanski - One of the best experts on this subject based on the ideXlab platform.
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clinical evaluation of a simultaneous closed loop Anaesthesia control system for Depth of Anaesthesia and neuromuscular blockade
Anaesthesia, 2011Co-Authors: M. Janda, Olaf Simanski, B. Pohl, J. Bajorat, Gabriele Noeldgeschomburg, R. HofmockelAbstract:Summary We developed a closed-loop system to control the Depth of Anaesthesia and neuromuscular blockade using the bispectral index and the electromyogram simultaneously and evaluated the clinical performance of this combined system for general Anaesthesia. Twenty-two adult patients were included in this study. Anaesthesia was induced by a continuous infusion of remifentanil at 0.4 μg.kg−1.min−1 (induction dose) and then 0.25 μg.kg−1.min−1 (maintenance dose) and propofol at 2 mg.kg−1 3 min later. The combined automatic control was started 2 min after tracheal intubation. The Depth of Anaesthesia was recorded using bispectral index monitoring using a target value of 40. The target value of neuromuscular blockade, using mivacurium, was a T1/T10 twitch height of 10%. The precision of the system was calculated using internationally defined performance parameters. Twenty patients were included in the data analysis. The mean (SD) duration of simultaneous control was 129 (69) min. No human intervention was necessary during the computer-controlled administration of propofol and mivacurium. All patients assessed the quality of Anaesthesia as ‘good’ to ‘very good’; there were no episodes of awareness. The mean (SD) median performance error, median absolute performance error and wobble for the control of Depth of Anaesthesia and for neuromuscular blockade were −0.31 (1.78), 6.76 (3.45), 6.32 (2.93) and −0.38 (1.68), 3.75 (4.83), 3.63 (4.69), respectively. The simultaneous closed-loop system using propofol and mivacurium was able to maintain the target values with a high level of precision in a clinical setting. You can respond to this article at http://www.Anaesthesiacorrespondence.com
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Clinical evaluation of a simultaneous closed‐loop Anaesthesia control system for Depth of Anaesthesia and neuromuscular blockade*
Anaesthesia, 2011Co-Authors: M. Janda, Olaf Simanski, B. Pohl, J. Bajorat, Gabriele Noeldge-schomburg, R. HofmockelAbstract:Summary We developed a closed-loop system to control the Depth of Anaesthesia and neuromuscular blockade using the bispectral index and the electromyogram simultaneously and evaluated the clinical performance of this combined system for general Anaesthesia. Twenty-two adult patients were included in this study. Anaesthesia was induced by a continuous infusion of remifentanil at 0.4 μg.kg−1.min−1 (induction dose) and then 0.25 μg.kg−1.min−1 (maintenance dose) and propofol at 2 mg.kg−1 3 min later. The combined automatic control was started 2 min after tracheal intubation. The Depth of Anaesthesia was recorded using bispectral index monitoring using a target value of 40. The target value of neuromuscular blockade, using mivacurium, was a T1/T10 twitch height of 10%. The precision of the system was calculated using internationally defined performance parameters. Twenty patients were included in the data analysis. The mean (SD) duration of simultaneous control was 129 (69) min. No human intervention was necessary during the computer-controlled administration of propofol and mivacurium. All patients assessed the quality of Anaesthesia as ‘good’ to ‘very good’; there were no episodes of awareness. The mean (SD) median performance error, median absolute performance error and wobble for the control of Depth of Anaesthesia and for neuromuscular blockade were −0.31 (1.78), 6.76 (3.45), 6.32 (2.93) and −0.38 (1.68), 3.75 (4.83), 3.63 (4.69), respectively. The simultaneous closed-loop system using propofol and mivacurium was able to maintain the target values with a high level of precision in a clinical setting. You can respond to this article at http://www.Anaesthesiacorrespondence.com
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Measurement and control of neuromuscular blockade and Depth of Anaesthesia
2003 European Control Conference (ECC), 2003Co-Authors: Olaf Simanski, R. Kähler, B. Pohl, R. Hofmockel, R. Friedrich, Bernhard P. LampeAbstract:The paper considers control problems for neuromuscular blockade and Depth of Anaesthesia. The control system is intended to be used in controlling the main parts of general Anaesthesia. The applied measurement techniques, experimental conditions and control strategies are presented. The results of a study with 31 patients for the control of neuromuscular blockade, and first trials for 6 patients for the control of Depth of Anaesthesia are listed.