Recording the middle latency response of the auditory evoked potential as a measure of depth of anaesthesia. A technical note.
ABSTRACT The middle latency response of the auditory evoked potential may be useful as an indicator of the hypnotic state during anaesthesia. However, it is difficult to record in some circumstances. This communication provides some suggestions and guidance for those not familiar with the technique.
Article: [In Process Citation].ains · Anästhesiologie · Intensivmedizin 02/2014; 49(2):80-2. DOI:10.1055/s-0034-1368672 · 0.34 Impact Factor
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ABSTRACT: Early postoperative cognitive dysfunction (POCD) is commonly associated with major surgery and anesthesia, occurring in 7 to 71% of patients [1-3]. Advanced age, degree of surgical trauma, depth of anesthesia and inflammatory activation are some of the risk factors for POCD [1,4-7]. It has been proposed that systemic inflammation may contribute to postoperative cognitive deficits and there could be a relationship between interleukin response and impaired postoperative cognition [8-10]. Monitoring the depth of anesthesia using digital processing of the EEG makes it possible to reduce anesthetic requirements and doses of opioids perioperatively, which can also influence POCD [5,11-14]. Inflammatory response and opioids are two risk factors for development of POCD [4,15]. The aim of this study was to evaluate the role of depth of anesthesia on POCD after major ENT surgery and to assess changes in postoperative inflammatory markers in patients undergoing major surgery. A selected group of experienced anesthesiologists or nurse anesthetists, specially trained in guiding anesthesia depth using auditory evoked potential (AEP, A-line), performed the anesthesia. The postoperative personnel were blinded to group assignment, and all data were processed independently of group allocation and were blinded to the investigator until the finalisation of the study. Randomisation procedure and baseline characteristics Patients were randomly assigned to one of two study groups: AEP group (group A): Anesthesia was guided by AEP: A-line ARX index (AAI), version 1.6. Mid-latency auditory evoked potential (MLAEP) was calculated using the A-line monitor (Danmeter A/S, Odense, Denmark) [16,17], AAI between 15 and 25 was regarded as adequate . Control group (group C): Anesthesia was guided by clinical signs of depth of anesthesia including blood pressure, heart rate, pupil reaction, sweating and lacrimation at the discretion of the attending anesthesiologist or nurse anesthetist. AEP was recorded in all patients in the control group but was blinded to the attending anesthesiologist or nurse anesthetist. After surgery, the data were transferred to storage media for later analysis of AAI. Citation: Jildenstål PK, Hallén JL, Rawal N, Berggren L (2012) Does Depth of Anesthesia Influence Postoperative Cognitive Dysfunction or Inflammatory Re-sponse Following Major ENT Surgery? J Anesth Clin Res 3:220. doi:10.4172/2155-6148.1000220 Copyright: © 2012 Jildenstål PK, et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits un-restricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Abstract The aim of this study was to evaluate the role of depth of anesthesia on POCD after major ENT surgery and to assess changes in postoperative inflammatory markers in patients undergoing major ENT surgery. Thirty two patients aged 40 to 94 yrs, scheduled for surgery under general anesthesia were randomly assigned to one of two groups. In group A (AEP group) depth of anesthesia (DOA) was measured with auditory evoked potential (AEP). In the control group (group C) DOA was monitored according to clinical signs. Cognitive function was evaluated using Mini-Mental State Examination (MMSE), Confusion Assessment Method (CAM) and Cognitive Failure Questionnaire (CFQ). Inflammatory markers were measured before and after anesthesia. Perioperative requirements for desflurane and fentanyl were significantly lower in group A. On the first postoperative day MMSE changes indicating POCD were noted in 1 patient in group A and 7 patients in group C (P<0.03). One month follow up did not show any difference between the groups regarding POCD. Our study indicates that AEP-guided anesthesia allows dose reduction of anesthetic agents including opioids leading to better cardiovascular stability and less early POCD. Anesthesia depth did not influence the inflammatory response to surgery.Journal of Clinical Anesthesia 07/2012; 3(6):1000220. · 1.21 Impact Factor
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ABSTRACT: In our daily practice in intensive care unit, one of the “cornerstones” is to achieve adequate sedation for every patient. Intensive care unit (ICU) patients are often sedated, and a good hypnotic monitoring is important to assure an optimal level of sedation for every patient. Sedation monitoring can be achieved using subjective or objective methods. The most recent recommendations on management of sedation were published by Critical Care Medicine in January 2013. They recommend the use of subjective methods as the primary method to monitor sedation, with the use of objective methods only in paralyzed and comatose patients, in whom subjective methods cannot be used. Unfortunately in these last recommendations, the objective methods of sedation monitoring are listed without indicating any of them as the best method actually available to assure an adequate sedation. The aim of our study is to review the characteristics of each objective method of sedation monitoring, in order to understand which is the most appropriate in the current state. We found that several objective methods are adequate to monitor the level of sedation in paralyzed or comatose patients, although the data needs to be considered with caution, Bispectral Index (BIS) is suggested as the best method for monitoring sedation in most studies.