Early postoperative delirium after open-heart cardiac surgery is associated with decreased bispectral EEG and increased cortisol and interleukin-6

Department of Anesthesiology, University of Heidelberg, Im Neuenheimer Feld 110, 69120, Heidelberg, Germany.
European Journal of Intensive Care Medicine (Impact Factor: 5.54). 12/2010; 36(12):2081-9. DOI: 10.1007/s00134-010-2004-4
Source: PubMed

ABSTRACT It is difficult to substantiate the clinical diagnosis of postoperative delirium with objective parameters in intensive care units (ICU). The purpose of this study was to analyze (1) whether the bilateral bispectral (BIS) index, (2) cortisol as a stress marker, and (3) interleukin-6 as a marker of inflammation were different in delirious patients as compared to nondelirious ones after cardiac surgery.
On the first postoperative day, delirium was analyzed in 114 patients by using the confusion assessment method for ICU (CAM-ICU). Bilateral BIS data were determined; immediately thereafter plasma samples were drawn to analyze patients' blood characteristics. The current ICU medication, hemodynamic characteristics, SOFA and APACHE II scores, and artificial ventilation were noted.
Delirium was detected at 19.1 ± 4.8 h after the end of surgery in 32 of 114 patients (28%). Delirious patients were significantly older than nondelirious ones and were artificially ventilated 4.7-fold more often during the testing. In delirious patients, plasma cortisol and interleukin-6 levels were higher (p = 0.01). The mean BIS index was significantly lower in delirious patients (72.6 (69.6-89.1); median [interquartile range (IQR), 25th-75th percentiles] than in nondelirious patients, 84.8 (76.8-89.9). BIS EEG raw data analysis detected significant lower relative alpha and higher theta power. A significant correlation was found between plasma cortisol levels and BIS index.
Early postoperative delirium after cardiac surgery was characterized by increased stress levels and inflammatory reaction. BIS index measurements showed lower cortical activity in delirious patients with a low sensitivity (27%) and high specificity (96%).

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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 [17]. 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: Objective Postoperative delirium is a common complication in the elderly after surgery but few papers have reported after spinal surgery. We analyzed various risk factors for postoperative delirium after spine surgery. Methods Between May 2012 and September 2013, 70 patients over 60 years of age were examined. The patients were divided into two groups : Group A with delirium and Group B without delirium. Cognitive function was examined with the Mini-Mental State Examination-Korea (MMSE-K), Clinical Dementia Rating (CDR) and Global Deterioration Scale (GDS). Information was also obtained on the patients' education level, underlying diseases, duration of hospital stay and laboratory findings. Intraoperative assessment included Bispectral index (BIS), type of surgery or anesthesia, blood pressure, fluid balance, estimated blood loss and duration of surgery. Results Postoperative delirium developed in 17 patients. The preoperative scores for the MMSE, CDR, and GDS in Group A were 19.1±5.4, 0.9±0.6, and 3.3±1.1. These were significantly lower than those of Group B (25.6±3.4, 0.5±0.2, and 2.1±0.7) (p<0.05). BIS was lower in Group A (30.2±6.8 compared to 35.4±5.6 in group B) (p<0.05). The number of BIS <40 were 5.1±3.1 times in Group A, 2.5±2.2 times in Group B (p<0.01). In addition, longer operation time and longer hospital stay were risk factors. Conclusion Precise analysis of risk factors for postoperative delirium seems to be more important in spinal surgery because the surgery is not usually expected to have an effect on brain function. Although no risk factors specific to spinal surgery were identified, the BIS may represent a valuable new intraoperative predictor of the risk of delirium.
    Journal of Korean Neurosurgical Society 07/2014; 56(1):28-33. DOI:10.3340/jkns.2014.56.1.28 · 0.52 Impact Factor

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