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European Journal of Anaesthesiology 08/2012; 17:21-22. · 2.23 Impact Factor
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ABSTRACT: HintergrundBei Propofolnarkosen mit unterschiedlichen Remifentanildosierungen sollte geprüft werden, inwieweit ein Elektroenzephalographie-
(EEG-)Monitoring zu Anpassungen der „Target-controlled-infusion“- (TCI-)Propofolzielkonzentration führt.
Material und MethodenMit Zustimmung der Ethikkommission erhielten 60Patienten [27 bis 69Jahre, Klassifikation der American Society of Anesthesiologists
(ASA)I–III] Narkosen mit Propofol (TCI, Diprifusor®, AstraZeneca, Wedel, Deutschland) und 0,2, 0,4 oder 0,6µg/kgKG/min Remifentanil
(Gruppe1 bis 3). Die Narkoseaufrechterhaltung erfolgte in tiefer Hypnose (EEG-Stadien D2/E0, EEG-Monitor: Narcotrend®, Version 2.0/5.0, Hersteller: MT MonitorTechnik, Bad Bramstedt, Deutschland).
ErgebnisseIn den Gruppen 1 bis 3 betrug die Propofolkonzentration (TCI) im „steady state“ im Mittel 3,02±0,86, 1,93±0,53 bzw. 1,60±0,55µg/ml
(p<0,001). Der Propofolverbrauch war bei Frauen größer als bei Männern (p<0,05). Frauen berichteten häufiger von Träumen während
der Narkose als Männer (p<0,05). Mit steigender intraoperativer Remifentanildosierung nahm der postoperative Analgetikumbedarf
ab (p<0,05).
SchlussfolgerungenDie Untersuchung macht deutlich, dass Remifentanil neben der analgetischen auch eine hypnotische Wirkungskomponente hat. Mit
zunehmender Remifentanildosierung nimmt der Propofolbedarf ab; mithilfe des EEG-Monitorings lassen sich Propofolzielkonzentrationen
geschlechts- und altersbezogen adaptieren.
BackgroundThe aim of this study was to examine to what extent the use of electroencephalography (EEG) monitoring leads to an adaptation
of the target-controlled infusion (TCI) concentration of propofol during propofol anaesthesia with different doses of remifentanil.
Patients and methodsWith ethics committee approval 60 patients (27-69 years old) with American Society of Anesthesiologists classification (ASA)
I–III received anaesthestics with propofol (TCI, Diprifusor®, AstraZeneca, Wedel, Deutschland) and 0.2, 0.4, or 0.6µg/kg
body weight remifentanil, respectively (groups 1-3). Anaesthesia was maintained at a level of deep hypnosis (EEG stages D2/E0, EEG monitor: Narcotrend®, version 2.0/5.0, manufacturer: MT MonitorTechnik, Bad Bramstedt, Germany).
ResultsDuring the steady state the propofol concentration in groups 1-3 was 3.02±0.86, 1.93±0.53 and 1.60±0.55µg/ml, respectively
(p<0.001). Women had a higher propofol consumption than men (p<0.05). Dreams during anaesthesia were more often reported by
women than by men (p<0.05). The need for postoperative analgesia decreased with an increasing intraoperative remifentanil
dose (p<0.05).
ConclusionsThe study demonstrates that remifentanil has both analgetic and hypnotic effects. With increasing remifentanil dose the propofol
requirement decreased and in this context EEG monitoring is useful to adapt the target concentrations of propofol to the patients’
age and gender.
SchlüsselwörterPropofol-Remifentanil-TCI-Narcotrend-EEG
KeywordsPropofol-Remifentanil-TCI-Narcotrend-EEG
Der Anaesthesist 04/2012; 59(2):126-134. · 0.99 Impact Factor
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ABSTRACT: Bei einer 62-jährigen Patientin ohne Epilepsieanamnese wurde bei einer Propofol-Remifentanil- und einer Sevofluran-Remifentanil-Lachgas-Narkose
routinemäßig das EEG mit dem EEG-Monitor Narcotrend überwacht. Bei der ersten Narkose stellte sich nach Gabe eines Bolus Propofol
1% eine fortschreitende Frequenzverlangsamung des EEG dar, das schließlich in ein Burst-Suppression-Muster überging. Während
dieser Anflutungsphase waren keine epilepsietypischen Potenziale vorhanden. Bei der zweiten Narkose trat dagegen, ausgehend
von einer Beatmung mit 2 Vol.-% Sevofluran, während einer Anflutung mit 8 Vol.-% nach 5 min bei einer endtidalen Konzentration
von 5,9 Vol.-% epilepsietypische Aktivität im EEG auf.
In a 62-year-old female patient without a history of epileptic seizures EEG monitoring (EEG monitor: Narcotrend) was routinely
performed during propofol/remifentanil and during sevoflurane/remifentanil/nitrous oxide anaesthesia. In the first course
of anaesthesia after a bolus of propofol 1% a continuous EEG slowing was followed by a burst suppression pattern without occurrence
of epileptiform activity throughout this sequence. During the second course of anaesthesia the sevoflurane concentration was
increased from 2 to 8 % by volume. After 5 min epileptiform activity appeared in the EEG at an endtidal concentration of 5.9%
by volume.
Der Anaesthesist 04/2012; 50(1):43-45. · 0.99 Impact Factor
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ABSTRACT: The aim of this study was to examine to what extent the use of electroencephalography (EEG) monitoring leads to an adaptation of the target-controlled infusion (TCI) concentration of propofol during propofol anaesthesia with different doses of remifentanil.
With ethics committee approval 60 patients (27-69 years old) with American Society of Anesthesiologists classification (ASA) I-III received anaesthestics with propofol (TCI, Diprifusor, AstraZeneca, Wedel, Deutschland) and 0.2, 0.4, or 0.6 microg/kg body weight remifentanil, respectively (groups 1-3). Anaesthesia was maintained at a level of deep hypnosis (EEG stages D(2)/E(0), EEG monitor: Narcotrend, version 2.0/5.0, manufacturer: MT MonitorTechnik, Bad Bramstedt, Germany).
During the steady state the propofol concentration in groups 1-3 was 3.02+/-0.86, 1.93+/-0.53 and 1.60+/-0.55 microg/ml, respectively (p<0.001). Women had a higher propofol consumption than men (p<0.05). Dreams during anaesthesia were more often reported by women than by men (p<0.05). The need for postoperative analgesia decreased with an increasing intraoperative remifentanil dose (p<0.05).
The study demonstrates that remifentanil has both analgetic and hypnotic effects. With increasing remifentanil dose the propofol requirement decreased and in this context EEG monitoring is useful to adapt the target concentrations of propofol to the patients' age and gender.
Der Anaesthesist 02/2010; 59(2):126-34. · 0.99 Impact Factor
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ABSTRACT: A reliable assessment of the depth of hypnosis during sedation and general anaesthesia using the EEG is a subject of current interest. The Narcotrend Index implemented in the latest version 4.0 of the EEG monitor Narcotrend provides an automatic classification of the EEG on a scale ranging from 100 (awake) to 0 (very deep hypnosis, EEG suppression). The classification algorithms implemented in the EEG monitor Narcotrend are described. In a study the correlation of the propofol effect-site concentration with the Narcotrend Index and with the traditional spectral parameters total power, relative power in the standard frequency bands delta, theta, alpha, and beta, median frequency, 95% spectral edge frequency, burst-compensated spectral edge frequency, and spectral entropy was investigated. The Narcotrend Index had the highest average correlation with the propofol effect-site concentration and the smallest variability of the individual correlation values. Moreover, the Narcotrend Index was the only parameter which showed a monophasic trend over the whole investigated time period. The Narcotrend monitor can make a significant contribution to the improvement of the quality of anaesthesia by adjusting the dosage of hypnotics to individual patient needs.
Biomedizinische Technik 04/2004; 49(3):38-42. · 0.86 Impact Factor
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ABSTRACT: Age-related differences in the spectral composition of the EEG in induction and emergence times, and in drug consumption during propofol anaesthesia were investigated.
The EEGs of 60 female patients between 22 and 85 years of age were monitored continuously during standardized induction of anaesthesia with 2 mg of propofol kg(-1)60 s(-1). The EEGs were visually assessed in 20-s epochs according to a scale from A (awake) to F (very deep hypnosis). Visual EEG classifications, spectral parameters, and induction times were compared between different age groups. Additionally, data of 546 patients included in a multicentre study with 4630 patients (EEG monitor Narcotrend, MT MonitorTechnik, Bad Bramstedt, Germany) were analyzed with regard to age-dependent changes of propofol consumption using target-controlled infusion (TCI).
During induction, patients older than 70 years reached significantly deeper EEG stages than younger patients, needed a longer time to reach the deepest EEG stage, and needed more time until a light EEG stage was regained. In patients aged 70 years and older, the total power, mainly in deep EEG stages, was significantly smaller due to a distinctly smaller absolute power of the delta frequency band. No single spectral parameter was able to reliably distinguish all EEG stages. During the steady state of anaesthesia, older patients needed less propofol for the maintenance of a defined stage of hypnosis than younger patients.
Older patients differ from younger ones regarding the hypnotic effect of propofol and the spectral patterns in the EEG. For an efficient automatic assessment of the EEG during anaesthesia a multivariable approach accounting for age-effects is indispensable.
Acta Anaesthesiologica Scandinavica 02/2004; 48(1):27-34. · 2.19 Impact Factor
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ABSTRACT: The Narcotrend performs an automatic interpretation of the electroencephalogram (EEG) during anaesthesia. The classification algorithms have been developed on the basis of visually classified EEG epochs. The classification scheme which was used for these visual assessments has its origin in sleep analysis and was adapted for the EEG during anaesthesia. From the awake state to very deep anaesthesia, 15 stages (A, B(0-2), C(0-2), D(0-2), E(0-2), F(0-1)) are distinguished. The transformation of these stages into a numerical scale from 100 to 0 is a further refinement for a differentiated presentation of EEG effects. For the automatic classification multivariate discriminant functions are used. Age-related changes of the EEG were incorporated. The device contains functions for the identification of artifacts. The EEG can be recorded from a frontal channel using standard ECG electrodes, other electrode positions and types can be chosen. The device has been clinically and scientifically validated.
Der Anaesthesist 01/2004; 52(12):1143-8. · 0.99 Impact Factor
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ABSTRACT: Cochlear implantation is a widely used means of treating deafness and severe hearing disorders. The surgical procedure includes inserting the cochlear implant electrode array into the cochlea and embedding the corresponding signal receiver in the mastoid bone behind the ear. Postoperative fitting of the externally worn speech processor is very important for successful use of the cochlear implant. For this purpose, electrically elicited stapedius reflex threshold values can be used. However, stapedius reflex threshold values measured intraoperatively are influenced by anaesthetics. The goal of this retrospective study was to find out whether electroencephalogram (EEG) control of anaesthesia produces more reliable reflex threshold values as a basis for the fitting of the speech processor.
Three groups of children, after surgery for cochlear implantation, were analysed with regard to the magnitude of intraoperative electrically elicited stapedius reflex threshold values and their deviations from postoperatively determined maximum comfortable levels (group 1: methohexital/remifentanil with EEG monitoring, n = 10; group 2: isoflurane/fentanyl with EEG monitoring, n = 9; group 3: isoflurane/fentanyl without EEG monitoring, n = 11).
Children with EEG monitoring had significantly lower electrically elicited stapedius reflex threshold values and also significantly lower differences between intraoperative stapedius reflex threshold values and postoperatively determined maximum comfortable levels.
Electroencephalogram monitoring in cochlear implantation is of considerable value in controlling anaesthesia and improving speech processor fitting based on more reliable intraoperative neurophysiological data.
Pediatric Anesthesia 12/2003; 13(9):790-6. · 2.10 Impact Factor
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ABSTRACT: Der Narcotrend fhrt eine automatische Interpretation des Narkoseelektroenzephalogramms (EEG) durch. Die Klassifikationsalgorithmen wurden auf der Grundlage von visuell bewerteten EEG-Abschnitten hergeleitet. Hierbei kam ein Schema zum Einsatz, das seine Ursprnge in der Schlafklassifikation hat und fr das Narkose-EEG adaptiert wurde. Vom Wachzustand bis zur sehr tiefen Narkose werden 15Stadien (A, B0–2, C0–2, D0–2, E0–2, F0–1) unterschieden. Eine Verfeinerung stellt die Transformation dieser EEG-Stadien in eine numerische Skala von 100–0 dar; hierdurch knnen EEG-Effekte noch differenzierter dargestellt werden. Fr die Klassifikation werden multivariate Diskriminanzfunktionen verwendet. Das System bercksichtigt altersabhngige Vernderungen des EEG und beinhaltet Algorithmen zur Identifizierung von Artefakten. Das EEG kann ber eine frontale Ableitung mit EKG-Elektroden abgeleitet werden; andere Elektrodenpositionen oder -typen sind mglich. Das System wurde klinisch und wissenschaftlich validiert.The Narcotrend performs an automatic interpretation of the electroencephalogram (EEG) during anaesthesia. The classification algorithms have been developed on the basis of visually classified EEG epochs. The classification scheme which was used for these visual assessments has its origin in sleep analysis and was adapted for the EEG during anaesthesia. From the awake state to very deep anaesthesia, 15 stages (A, B0–2, C0–2, D0–2, E0–2, F0–1) are distinguished. The transformation of these stages into a numerical scale from 100 to 0 is a further refinement for a differentiated presentation of EEG effects. For the automatic classification multivariate discriminant functions are used. Age-related changes of the EEG were incorporated. The device contains functions for the identification of artifacts. The EEG can be recorded from a frontal channel using standard ECG electrodes, other electrode positions and types can be chosen. The device has been clinically and scientifically validated.
Der Anaesthesist 11/2003; 52(12):1143-1148. · 0.99 Impact Factor
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Anaesthesia and intensive care 01/2003; 30(6):817-8. · 1.28 Impact Factor
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Der Anaesthesist 10/2001; 50(11):885-886. · 0.99 Impact Factor
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ABSTRACT: In this article unexpected EEG findings are described which were observed during EEG monitoring under sevoflurane anesthesia.
In seven non-epileptic adult patients sevoflurane was administered as inhalation anesthetic during routinely performed surgical operations. The EEG was recorded continuously as part of the standard monitoring process and served mainly as a dosage guide for anesthetics/narcotics.
Occurrence of sharp transients in the EEG resembling distinctive waves which can be seen in epileptic disorders.
In six of the seven patients under 8.0% sevoflurane, sharp transients were observed which appeared in very deep EEG stages, mostly with endtidal sevoflurane concentrations of 4.8-5.9%. The findings are in accordance with observations in non-epileptic children from our clinic.
The clinical significance of the observed EEG pattern under sevoflurane anesthesia is still unclear. Taking into consideration that convulsive and nonconvulsive status epilepticus can be followed by signs of brain damage, it would appear to be important to further investigate the phenomenon.
Pharmacy World amp Science 05/2001; 23(2):82-5. · 1.22 Impact Factor
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ABSTRACT: EEG monitoring can be performed at the patients' bedside and it is a valuable support in therapeutic decision making providing unique information about the functional state of the brain. Due to newer technical developments, EEG monitoring can be conducted rather easily. In this article, indications for EEG monitoring in plastic surgical patients are presented: controlling the level of sedation, use in states of increased intracranial pressure, screening the cerebral state in comatose patients, diagnosis and therapy of epileptic seizures, and the search for circumscribed cerebral abnormalities. Furthermore, practical experience with the use of the new EEG monitor Narcotrend, which is provided with an automatic EEG classification, is described.
Handchirurgie · Mikrochirurgie · Plastische Chirurgie 04/2001; 33(2):129-32. · 0.88 Impact Factor
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ABSTRACT: In a 62-year-old female patient without a history of epileptic seizures EEG monitoring (EEG monitor: Narcotrend) was routinely performed during propofol/remifentanil and during sevoflurane/remifentanil/nitrous oxide anaesthesia. In the first course of anaesthesia after a bolus of propofol 1% a continuous EEG slowing was followed by a burst suppression pattern without occurrence of epileptiform activity throughout this sequence. During the second course of anaesthesia the sevoflurane concentration was increased from 2 to 8 % by volume. After 5 min epileptiform activity appeared in the EEG at an endtidal concentration of 5.9% by volume.
Der Anaesthesist 02/2001; 50(1):43-5. · 0.99 Impact Factor
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ABSTRACT: Two case reports of nonepileptic children are presented, who developed paroxysmal EEG potentials in routinely performed EEG recordings during inhalation of sevoflurane, 7 and 8% by volume respectively. Taking into account several reports from the literature about epileptiform potentials or convulsive movements under similar conditions, it seems to be important to investigate carefully the circumstances under which these phenomena appear as well as possible clinical consequences.
Anaesthesia and intensive care 05/2000; 28(2):205-7. · 1.28 Impact Factor
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Anaesthesia and intensive care 07/1998; 26(3):329. · 1.28 Impact Factor
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ABSTRACT: The number of older persons who have to undergo surgical procedures is steadily growing. For these patients the risks of anaesthesia are often increased because of their past medical history and their restricted physiological resources. Apart from parameters of the cardiovascular system, the electroencephalogram (EEG) represents a supplementary method for intraoperative monitoring, because cerebral alterations caused by anaesthetics or narcotics are directly reflected in the EEG. In routinely conducted registrations of the EEG in the operating theatre it appeared that the EEG of older persons differed from the EEG of younger patients. The aim of the present study was to further investigate the effect of patients' age on the EEG during anaesthesia. METHODS. Three data sets from different EEG registrations were analysed. The first data set consisted of inductions of anaesthesia with 7 mg/kg body weight thiopental in 43 patients from 17 to 80 years of age (mean 53.6 +/- 16.7 years) using derivations C3-P3 and Cz-A1. The second data set included 69 EEG registrations of general anaesthesia induced with barbiturates and maintained with enflurane in patients from 16 to 83 years (mean 51.4 +/- 17.7 years). The third data set comprised inductions of anaesthesia with 2 mg/kg body weight propofol. EEGs of the second and third data set were recorded with the EEG monitor 'Narkograph' using derivation C3-P3 and derivations C3-P3/C4-P4, respectively. Classification of the EEGs was performed according to the proposals of Kugler [12]. The basis for the statistical analysis of all data sets was formed by parameters from the power spectra of the EEG recordings. RESULTS. The data from inductions of anaesthesia with thiopental and propofol showed EEG patterns from alpha-EEG to burst suppression activity, whereby periods with burst suppressions could more often be observed in the EEG of older people. Under thiopental burst suppression activity occurred in 20% of patients up to 50 years, in 47% of those between 50 and 70 years and in 89% over 70 years. The corresponding figures for propofol were 0%, 5% and 54%, respectively. Figure 2 depicts the correlation between age and power for the thiopental data. The power decreases with increasing age of the patients. This result led to further investigations of the effect of patients' age on the power in different EEG stages. Of special interest were deep stages of anaesthesia, because especially in these stages visual inspections revealed smaller amplitudes of the EEG signal for older patients than for younger persons. Figure 3 shows the power in the delta frequency band in deep stages of barbiturate-induced enflurane anaesthesia for patients of different age groups. The power in the delta frequency band distinctly decreases for geriatric patients. The same effect could be observed for the propofol data (Fig. 4). CONCLUSIONS. The EEG represents an important method for effective intraoperative monitoring and contributes to an individually adjusted course of anaesthesia, especially for geriatric patients. In these patients, clinical signs such as parameters of the cardiovascular system, which are usually used to judge the depth of anaesthesia, are often altered by the patient's past medical history or by drugs. Furthermore, geriatric patients show a reduced need for narcotic agents. However, the variation of the required dosage is greater in older than in younger persons. The results of the present study show that with regard to an automatic classification of the EEG during anaesthesia, alterations of the EEG with age have to be taken into account.
Der Anaesthesist 08/1995; 44(7):467-72. · 0.99 Impact Factor
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ABSTRACT: Discriminant analysis plays an important role in biological and medical research. The most popular methods of discrimination in practical applications are parametric methods like linear and quadratic discriminant analysis. However, there exist modifications of these approaches, namely unbiased and predictive discriminant analysis, which lead to reduced error rates in certain situations. In this paper a menu-driven, user-friendly PC program written in Borland Pascal 7.0 is introduced which performs unbiased and predictive linear and quadratic discriminant analysis.
Computers in Biology and Medicine 08/1995; 25(4):425-30. · 1.09 Impact Factor
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ABSTRACT: The conventional multichannel electroencephalogram is quite inconvenient for long-term monitoring in the operating theatre or intensive care unit. Recording of the EEG would be easier if a small number of channels was sufficient. Aiming at reduction of channels, leads from different regions of the scalp were analysed visually and with regard to their spectral content. METHODS. Electrode placements corresponded to the International 10/20 System (Fig. 1). EEG recordings were made with a conventional device (ES 12,000), a personal computer, and a spectral analyser. TWO-CHANNEL RECORDINGS. Retrospective analysis was performed on data from 392 patients (age 14-90 years) whose anaesthesia was induced with various anaesthetics/narcotics, for instance thiopental, ketamine, etomidate, halothane, and enflurane. The EEG was recorded using C3-P3 and Cz-A1. For each patient the changes of spectral parameters during the course of the induction were plotted and visually analysed. For statistical analyses a 30-s epoch of each patient was randomly selected from the first few minutes after the beginning of induction. TEN-CHANNEL RECORDINGS. In ten gynaecological patients (age 26-55 years) EEG recordings were performed during induction of anaesthesia with thiopental in combination with fentanyl, N2O and O2. The set of channels consisted of Fz'-Cb1, F3'-Cb1, Cz-Cb1, C3-Cb1, P3-Cb1, Oz-Cb1, Fz'-F3', F3'-C3, C3-P3, and P3-Oz. The electrodes Fz' and F3' were positioned on the forehead near to Fz and F3, respectively. These sites were chosen because they allow easy application of electrodes. The relationship between channels was calculated with Bravais-Person's coefficient of correlation for the power and the absolute power in the frequency bands delta (0.5-3.5 Hz), theta (3.5-7.5 Hz), alpha (7.5-12.5 Hz), and beta (> 12.5 Hz). RESULTS. In visual and statistical analyses of the two- and ten-channel recordings under the influence of anaesthetics/narcotics, similar changes of EEG activity could be observed in all channels. Although differences in the absolute power of the frequency bands were present, there was high conformity in the composition of the spectral content of the different channels. Classification of the EEG into stages of anaesthesia by means of a single channel led to consistent results for all channels. Alpha activity as leading feature of the awake state predominated occipitally. In channels including the region around the ears, contamination with EKG artifacts was observed. CONCLUSIONS. EEG patterns under the influence of different anaesthetics/narcotics are adequately represented by a reduced number of channels. For the choice of an appropriate set of channels the following aspects should be considered. Contamination with artifacts should be as low as possible, electrode sites should easily be accessible, and special features of the awake state should be identifiable. Experience with routinely conducted EEG recordings in the operating theatre and the intensive care unit showed that the channels C3-P3 or C4-P4 provide a sufficient basis for automatic staging of the depth of anaesthesia, which is implemented in the EEG monitor Narkograph.
Der Anaesthesist 07/1995; 44(7):473-7. · 0.99 Impact Factor
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ABSTRACT: Alterations of the cerebral function caused by anesthetics or due to potentially harmful situations are reflected in the electroencephalogram (EEG). Nevertheless, the EEG has not become a routine monitoring device so far because of the complicated and time-consuming recording procedure. Furthermore, interpretation of the EEG requires special knowledge. In order to facilitate the use of the EEG in the theatre and the intensive care unit a new monitoring device the Narkograph, was developed. To our knowledge, the Narkograph is the first monitor for day-to-day use which performs an automatic classification of drug-induced changes of the EEG in real-time. Staging into different levels of anesthesia is performed according to proposals made by Kugler (1981). By means of several case reports the use of the Narkograph and the benefits of routinely conducted EEG monitoring are presented. As, due to the on-line interpretation of EEG data, information on the current functional status of the brain can easily be obtained, the Narkograph is considered an essential contribution to the patients' security.
The International journal of risk & safety in medicine 01/1994; 6(2):119-28.
