Article

Einfluss von EEG-Monitoring, Alter und Geschlecht auf den Propofolbedarf während neurochirurgischer Eingriffe

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Abstract

Einleitung: Bei neurochirurgischen Patienten wurden Narkosen mit und ohne EEG-Monitoring verglichen, um den Einfluss des EEG-Monitorings, des Patientenalters und des Geschlechts auf die Propofoldosierungen zu untersuchen. Methodik: Es wurden Anästhesien mit Propofol (Disoprivan 2%) bei 76 Patienten (16–78 Jahre alt) mit Tumorkraniotomien untersucht. Bei 50 Patienten erfolgte die Narkosesteuerung unter Zuhilfenahme des EEG-Monitorings (Gruppe 1), bei 26 Patienten allein anhand klinischer Kriterien (Gruppe 2). Die Patienten beider Gruppen erhielten entweder 0,25 μg/kg KG/min (ohne Lachgas) oder 0,15 μg/kg KG/min (mit Lachgas) Remifentanil. Der angestrebte EEG-Stadienbereich während der Narkoseaufrechterhaltung war D2/E0, der einer tiefen Hypnose entspricht [EEG-Monitor: Narcotrend® (MT MonitorTechnik, Bad Bramstedt, Deutschland)]. Ergebnisse: Das EEG-Monitoring führte zu einer niedrigeren (p<0,001) und altersspezifischen (p=0,016) Propofoldosierung. Mit EEG-Monitoring wurde eine Tendenz zu höheren Dosierungen bei Frauen im Vergleich zu Männern beobachtet (Differenz: 15%, p=0,19). Patienten mit EEG-Monitoring wurden früher extubiert als Patienten ohne EEG-Überwachung (p<0,001). Bei Patienten ohne EEG-Überwachung ergab sich keine Korrelation zwischen dem Patientenalter und der Propofoldosierung. Schlussfolgerung: Das EEG-Monitoring unterstützt eine individuelle Dosierung von Propofol. Die signifikante Propofoleinsparung und der hohe Anteil von frühen Extubationen implizieren einen gesundheitsökonomischen Vorteil des EEG-Monitorings.

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Chapter
In this chapter, two kinds of cerebral monitoring are presented: electroencephalography (EEG) monitoring and intracranial pressure (ICP) monitoring. EEG monitoring is used in the operating room to assess the depth of hypnosis during anesthesia and to detect effects of hypoxia and of induced hypothermia. In intensive care unit patients, EEG monitoring can be used for the control of sedation, for therapy control, e.g. in status epilepticus, for the assessment of the patient’s current clinical status and trends thereof, and as an exploratory diagnostic tool with respect to epileptiform activity and focal brain disorders. Hypnotic drug effects are accompanied in a dose related manner by a slowing of the EEG. These EEG changes can be classified automatically. Especially through the automatic interpretation, EEG monitoring can be carried out as a routine method for patient monitoring with little effort. The aim of detecting and treating elevated ICP is to avoid secondary damage to the brain. The most common indication for ICP monitoring is trauma to the head. Methods for ICP measurement with higher invasiveness include intraventricular, intraparenchymal, or subdural catheter localisations. A less invasive method is epidural cerebral pressure measurement.
Chapter
Die Registrierung der Hirnströme (Elektroenzephalogramm, EEG) eignet sich zur Patientenüberwachung im Operationssaal und auf der Intensivstation (Freye u. Levy 2005).
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Impacts of hypnotic drugs on brain function are reflected in the EEG. The EEG monitor Narcotrend performs an automatic classification of the EEG using a scale which was proposed by Kugler for visual evaluation of the EEG. In this article the results of a validation study of the automatic classification algorithms implemented in the EEG monitor Narcotrend are presented. Visual and automatic classification of EEG data recorded in routine clinical practice were compared. The correlation between visual and automatic assessment was high (Spearman rank correlation r = 0.90, prediction probability Pk = 0.90) and a sufficient agreement between visual and automatic assessment was achieved for 92% of the analysed EEG epochs. The results of the study suggest that the automatic classification algorithms implemented in the EEG monitor Narcotrend yield a reliable assessment of the depth of hypnosis.
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The Narcotrend is a new EEG monitor designed to measure the hypnotic component of anaesthesia; however, a major clinical evaluation is still missing. This prospective multicentre study was designed to investigate the feasibility of Narcotrend monitoring in a large number of patients under different clinical conditions and to define its impact on recovery times after propofol-based total intravenous anaesthesia. After legal authority approval and patients'informed consent had been obtained, total intravenous anaesthesia was induced and maintained with propofol and an opioid analgesic at the discretion of the attending anaesthesiologist. In the first 10-15 patients of each centre the anaesthesiologist was blinded to the Narcotrend recordings and propofol was dosed according to clinical needs. In the following patients propofol was infused at a rate sufficient to achieve a target Narcotrend stage of D or E. With termination of propofol infusion,recovery times were recorded and analysed for the patients with or without Narcotrend monitoring; in addition, recovery times were analysed depending on the Narcotrend stage at the moment of termination of propofol infusion. In total, 4,630 adult patients were studied at 46 institutions, 521 without and 4,109 with Narcotrend monitoring. Demographic data and duration of anaesthesia were comparable. Emergence from anaesthesia was significantly shorter in Narcotrend monitored patients, e.g.opening eyes after 9.8+/-5.9 (mean+/-SD) vs.11.8+/-7.1 min. In addition,awakening was significantly more rapid when the propofol infusion was stopped at a lower level of hypnosis as indicated by Narcotrend monitoring, e.g.opening eyes after 7.1+/-4.5 min with stage C instead of 17.0+/-7.4 min with stage F. The EEG monitor Narcotrend can be used for adult patients of different ages and during various surgical procedures.Narcotrend monitoring facilitates a reduction of recovery times after propofol-based total intravenous anaesthesia,presumably by allowing for an individual titration of the propofol dosage. Moreover, it appears that the profile of recovery can be optimised when at the end of surgery,the propofol infusion is controlled to Narcotrend stage C instead of D, E, or F.
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Surgical injury can be followed by pain, nausea, vomiting and ileus, stress-induced catabolism, impaired pulmonary function, increased cardiac demands, and risk of thromboembolism. These problems can lead to complications, need for treatment in hospital, postoperative fatigue, and delayed convalescence. Development of safe and short-acting anaesthetics, improved pain relief by early intervention with multimodal analgesia, and stress reduction by regional anaesthetic techniques, beta-blockade, or glucocorticoids have provided important possibilities for enhanced recovery. When these techniques are combined with a change in perioperative care a pronounced enhancement of recovery and decrease in hospital stay can be achieved, even in major operations. The anaesthetist has an important role in facilitating early postoperative recovery by provision of minimally-invasive anaesthesia and pain relief, and by collaborating with surgeons, surgical nurses, and physiotherapists to reduce risk and pain.
Article
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