Electroencephalography-based monitors

Abstract

An electroencephalogram (EEG), detects changes and abnormalities in the electrical activity of the brain and thus provides a way to dynamically assess brain function. EEG may be used to diagnose and manage a number of clinical conditions such as epilepsy, convulsive and non-convulsive status epilepticus, encephalitis, barbiturate coma, brain death, etc., EEG provides a large amount of information to the anaesthesiologist for routine clinical practice as depth of anaesthesia monitors and detection of sub-clinical seizures; and also for understanding the complex mechanisms of anaesthesia-induced alteration of consciousness. In the initial years, the routine clinical applicability of EEG was hindered by the complexity of the raw EEG signal. However, with technological advancement, several EEG-derived dimensionless indices have been developed that correlate with the depth of the hypnotic component of anaesthesia and are easy to interpret. Similarly, with the development of quantitative EEG tools, the routine use of continuous EEG is ever expanding in the Intensive Care Units. This review, describe various commonly used EEG-based monitors and their clinical applicability in the field of anaesthesia and critical care.

Keywords

Continuous electroencephalogram monitor - depth of anaesthesia monitor - electroencephalogram - monitoring - quantitative electroencephalogram monitor

• REFERENCES

• 1 Gibbs FA, Gibbs EL, Lennox WG. Effect on the electroencephalogram of certain drugs which influence nervous activity. Arch Intern Med 1937; 60: 154-6
• 2 Newman J. Thalamic contributions to attention and consciousness. Conscious Cogn 1995; 4: 172-93
• 3 Stockard J, Bickford R. The neurophysiology of anesthesia. In: Gordon E. editor. A Basis and Practice of Neuroanesthesia. New York: Excerpta Medica; 1981. p. 3-50
• 4 Jameson LC, Sloan TB. Using EEG to monitor anesthesia drug effects during surgery. J Clin Monit Comput 2006; 20: 445-72
• 5 Rampil IJ. A primer for EEG signal processing in anesthesia. Anesthesiology 1998; 89: 980-1002
• 6 Tonner PH, Bein B. Classic electroencephalographic parameters: Median frequency, spectral edge frequency etc.. Best Pract Res Clin Anaesthesiol 2006; 20: 147-59
• 7 Rampil IJ, Correll JW, Rosenbaum SH, Quest DO, Holzer JA. Computerized electroencephalogram monitoring and carotid artery shunting. Neurosurgery 1983; 13: 276-9
• 8 Johansen JW. Update on bispectral index monitoring. Best Pract Res Clin Anaesthesiol 2006; 20: 81-99
• 9 Viertiö-Oja H, Maja V, Särkelä M, Talja P, Tenkanen N, Tolvanen-Laakso H. et al. Description of the Entropy algorithm as applied in the Datex-Ohmeda S/5 Entropy Module. Acta Anaesthesiol Scand 2004; 48: 154-61
• 10 Takamatsu I, Ozaki M, Kazama T. Entropy indices vs the bispectral index for estimating nociception during sevoflurane anaesthesia. Br J Anaesth 2006; 96: 620-6
• 11 Drover D, Ortega HR. Patient state index. Best Pract Res Clin Anaesthesiol 2006; 20: 121-8
• 12 Jensen EW, Litvan H, Revuelta M, Rodriguez BE, Caminal P, Martinez P. et al. Cerebral state index during propofol anesthesia: A comparison with the bispectral index and the A-line ARX index. Anesthesiology 2006; 105: 28-36
• 13 Kreuer S, Bruhn J, Larsen R, Grundmann U, Shafer SL, Wilhelm W. Application of bispectral index and narcotrend index to the measurement of the electroencephalographic effects of isoflurane with and without burst suppression. Anesthesiology 2004; 101: 847-54
• 14 Zikov T, Bibian S, Dumont GA, Huzmezan M, Ries CR. Quantifying cortical activity during general anesthesia using wavelet analysis. IEEE Trans Biomed Eng 2006; 53: 617-32
• 15 Schmidt GN, Bischoff P, Standl T, Lankenau G, Hellstern A, Hipp C. et al. SNAP index and bispectral index during different states of propofol/remifentanil anaesthesia. Anaesthesia 2005; 60: 228-34
• 16 Stoppe C, Peters D, Fahlenkamp AV, Cremer J, Rex S, Schälte G. et al. aepEX monitor for the measurement of hypnotic depth in patients undergoing balanced xenon anaesthesia. Br J Anaesth 2012; 108: 80-8
• 17 Sebel PS, Bowdle TA, Ghoneim MM, Rampil IJ, Padilla RE, Gan TJ. et al. The incidence of awareness during anesthesia: A multicenter United States study. Anesth Analg 2004; 99: 833-9
• 18 National Institute for Health and Care Excellence. DG 6. Depth of Anaesthesia Monitors – Bispectral Index, E-Entropy and Narcotrend-Compact M. Available from: http://www.nice.org.uk/dg6 [Last accessed on 16 May 2015].
• 19 Smith D, Andrzejowski J, Smith A. Certainty and uncertainty: NICE guidance on ‘depth of anaesthesia’ monitoring. Anaesthesia 2013; 68: 1000-5
• 20 Schultz A, Siedenberg M, Grouven U, Kneif T, Schultz B. Comparison of Narcotrend Index, Bispectral Index, spectral and entropy parameters during induction of propofol-remifentanil anaesthesia. J Clin Monit Comput 2008; 22: 103-11
• 21 Ekman A, Lindholm ML, Lennmarken C, Sandin R. Reduction in the incidence of awareness using BIS monitoring. Acta Anaesthesiol Scand 2004; 48: 20-6
• 22 Myles PS, Leslie K, McNeil J, Forbes A, Chan MT. bispectral index monitoring to prevent awareness during anaesthesia: The B-Aware randomised controlled trial. Lancet 2004; 363: 1757-63
• 23 Avidan MS, Zhang L, Burnside BA, Finkel KJ, Searleman AC, Selvidge JA. et al. Anesthesia awareness and the bispectral index. N Engl J Med 2008; 358: 1097-108
• 24 Avidan MS, Jacobsohn E, Glick D, Burnside BA, Zhang L, Villafranca A. et al. Prevention of intraoperative awareness in a high-risk surgical population. N Engl J Med 2011; 365: 591-600
• 25 Zhang C, Xu L, Ma YQ, Sun YX, Li YH, Zhang L. et al. bispectral index monitoring prevent awareness during total intravenous anesthesia: A prospective, randomized, double-blinded, multi-center controlled trial. Chin Med J (Engl) 2011; 124: 3664-9
• 26 Mashour GA, Shanks A, Tremper KK, Kheterpal S, Turner CR, Ramachandran SK. et al. Prevention of intraoperative awareness with explicit recall in an unselected surgical population: A randomized comparative effectiveness trial. Anesthesiology 2012; 117: 717-25
• 27 Avidan MS, Mashour GA. Prevention of intraoperative awareness with explicit recall: Making sense of the evidence. Anesthesiology 2013; 118: 449-56
• 28 Horn B, Pilge S, Kochs EF, Stockmanns G, Hock A, Schneider G. A combination of electroencephalogram and auditory evoked potentials separates different levels of anesthesia in volunteers. Anesth Analg 2009; 108: 1512-21
• 29 Castro A, Amorim P, Nunes CS. Modeling state entropy of the EEG and auditory evoked potentials: Hypnotic and analgesic interactions. Conf Proc IEEE Eng Med Biol Soc 2007; 2007: 1949-52
• 30 Röpcke H, Rehberg B, Koenen-Bergmann M, Bouillon T, Bruhn J, Hoeft A. Surgical stimulation shifts EEG concentration-response relationship of desflurane. Anesthesiology 2001; 94: 390-9
• 31 Röpcke H, Wirz S, Bouillon T, Bruhn J, Hoeft A. Pharmacodynamic interaction of nitrous oxide with sevoflurane, desflurane, isoflurane and enflurane in surgical patients: Measurements by effects on EEG median power frequency. Eur J Anaesthesiol 2001; 18: 440-9
• 32 Liu SS. Effects of bispectral Index monitoring on ambulatory anesthesia: A meta-analysis of randomized controlled trials and a cost analysis. Anesthesiology 2004; 101: 311-5
• 33 Ellerkmann RK, Kreuer S, Wilhelm W, Röpcke H, Hoeft A, Bruhn J. Reduction in anaesthetic drug consumption is correlated with mean titrated intra-operative bispectral index values. Acta Anaesthesiol Scand 2006; 50: 1244-9
• 34 Absalom AR, Kenny GN. Closed-loop control of propofol anaesthesia using bispectral index: Performance assessment in patients receiving computer-controlled propofol and manually controlled remifentanil infusions for minor surgery. Br J Anaesth 2003; 90: 737-41
• 35 Struys MM, Mortier EP, De Smet T. Closed loops in anaesthesia. Best Pract Res Clin Anaesthesiol 2006; 20: 211-20
• 36 Morimoto Y, Monden Y, Ohtake K, Sakabe T, Hagihira S. The detection of cerebral hypoperfusion with bispectral index monitoring during general anesthesia. Anesth Analg 2005; 100: 158-61
• 37 Azim N, Wang CY. The use of bispectral index during a cardiopulmonary arrest: A potential predictor of cerebral perfusion. Anaesthesia 2004; 59: 610-2
• 38 Shibata S, Imota T, Shigeomi S, Sato W, Enzan K. Use of the bispectral index during the early postresuscitative phase after out-of-hospital cardiac arrest. J Anesth 2005; 19: 243-6
• 39 el-Dawlatly AA. EEG bispectral index during carotid endarterectomy. Middle East J Anaesthesiol 2003; 17: 287-93
• 40 Mérat S, Lévecque JP, Le Gulluche Y, Diraison Y, Brinquin L, Hoffmann JJ. BIS monitoring may allow the detection of severe cerebral ischemia. Can J Anaesth 2001; 48: 1066-9
• 41 Deogaonkar A, Vivar R, Bullock RE, Price K, Chambers I, Mendelow AD. bispectral index monitoring may not reliably indicate cerebral ischaemia during awake carotid endarterectomy. Br J Anaesth 2005; 94: 800-4
• 42 Godet G, Reina M, Raux M, Amour J, De Castro V, Coriat P. Anaesthesia for carotid endarterectomy: Comparison of hypnotic- and opioid-based techniques. Br J Anaesth 2004; 92: 329-34
• 43 Umegaki N, Hirota K, Kitayama M, Yatsu Y, Ishihara H, Mtasuki A. A marked decrease in bispectral index with elevation of suppression ratio by cervical haematoma reducing cerebral perfusion pressure. J Clin Neurosci 2003; 10: 694-6
• 44 Lavine SD, Masri LS, Levy ML, Giannotta SL. Temporary occlusion of the middle cerebral artery in intracranial aneurysm surgery: Time limitation and advantage of brain protection. J Neurosurg 1997; 87: 817-24
• 45 Stone JG, Young WL, Marans ZS, Solomon RA, Smith CR, Jamdar SC. et al. Consequences of electroencephalographic-suppressive doses of propofol in conjunction with deep hypothermic circulatory arrest. Anesthesiology 1996; 85: 497-501
• 46 Batjer HH. Cerebral protective effects of etomidate: Experimental and clinical aspects. Cerebrovasc Brain Metab Rev 1993; 5: 17-32
• 47 Loskota WJ. Intraoperative EEG monitoring. Seminars in anesthesia, perioperative medicine and pain 2005; 24: 176-85
• 48 Mathews DM, Clark L, Johansen J, Matute E, Seshagiri CV. Increases in electroencephalogram and electromyogram variability are associated with an increased incidence of intraoperative somatic response. Anesth Analg 2012; 114: 759-70
• 49 Guerrero JL, Matute E, Alsina E, Del Blanco B, Gilsanz F. Response entropy changes after noxius stimulus. J Clin Monit Comput 2012; 26: 171-5
• 50 Punjasawadwong Y, Boonjeungmonkol N, Phongchiewboon A. bispectral index for improving anaesthetic delivery and postoperative recovery. Cochrane Database Syst Rev 2007; 4 DOI: CD003843.
• 51 Pavlin JD, Souter KJ, Hong JY, Freund PR, Bowdle TA, Bower JO. Effects of bispectral index monitoring on recovery from surgical anesthesia in 1,580 inpatients from an academic medical center. Anesthesiology 2005; 102: 566-73
• 52 Fritz BA, Rao P, Mashour GA, Abdallah AB, Burnside BA, Jacobsohn E. et al. Postoperative recovery with bispectral index versus anesthetic concentration-guided protocols. Anesthesiology 2013; 118: 1113-22
• 53 Monk TG, Saini V, Weldon BC, Sigl JC. Anesthetic management and one-year mortality after noncardiac surgery. Anesth Analg 2005; 100: 4-10
• 54 Lindholm ML, Träff S, Granath F, Greenwald SD, Ekbom A, Lennmarken C. et al. Mortality within 2 years after surgery in relation to low intraoperative bispectral index values and preexisting malignant disease. Anesth Analg 2009; 108: 508-12
• 55 Leslie K, Myles PS, Forbes A, Chan MT. The effect of bispectral index monitoring on long-term survival in the B-aware trial. Anesth Analg 2010; 110: 816-22
• 56 Kertai MD, Pal N, Palanca BJ, Lin N, Searleman SA, Zhang L. et al. Association of perioperative risk factors and cumulative duration of low bispectral index with intermediate-term mortality after cardiac surgery in the B-Unaware Trial. Anesthesiology 2010; 112: 1116-27
• 57 Sessler DI, Sigl JC, Kelley SD, Chamoun NG, Manberg PJ, Saager L. et al. Hospital stay and mortality are increased in patients having a “triple low” of low blood pressure, low bispectral index, and low minimum alveolar concentration of volatile anesthesia. Anesthesiology 2012; 116: 1195-203
• 58 Bonhomme V, Boveroux P, Brichant JF, Laureys S, Boly M. Neural correlates of consciousness during general anesthesia using functional magnetic resonance imaging (fMRI). Arch Ital Biol 2012; 150: 155-63
• 59 Bonhomme V, Boveroux P, Hans P, Brichant JF, Vanhaudenhuyse A, Boly M. et al. Influence of anesthesia on cerebral blood flow, cerebral metabolic rate, and brain functional connectivity. Curr Opin Anaesthesiol 2011; 24: 474-9
• 60 Friston K, Moran R, Seth AK. Analysing connectivity with Granger causality and dynamic causal modelling. Curr Opin Neurobiol 2013; 23: 172-8
• 61 Flink R, Pedersen B, Guekht AB, Malmgren K, Michelucci R, Neville B. et al. Guidelines for the use of EEG methodology in the diagnosis of epilepsy. International League Against Epilepsy: Commission report. Commission on European Affairs: Subcommission on European Guidelines. Acta Neurol Scand 2002; 106: 1-7
• 62 Tripathi M, Garg A, Gaikwad S, Bal CS, Chitra S, Prasad K. et al. Intra-operative electrocorticography in lesional epilepsy. Epilepsy Res 2010; 89: 133-41
• 63 Zumsteg D, Wieser HG. Presurgical evaluation: Current role of invasive EEG. Epilepsia 2000; 41 Suppl (Suppl. 03) S55-60
• 64 Sutter R, Stevens RD, Kaplan PW. Continuous electroencephalographic monitoring in critically ill patients: Indications, limitations, and strategies. Crit Care Med 2013; 41: 1124-32
• 65 Gilmore EJ, Gaspard N, Choi HA, Cohen E, Burkart KM, Chong DH. et al. Acute brain failure in severe sepsis: A prospective study in the medical intensive care unit utilizing continuous EEG monitoring. Intensive Care Med 2015; 41: 686-94
• 66 Claassen J, Taccone FS, Horn P, Holtkamp M, Stocchetti N, Oddo M. et al. Recommendations on the use of EEG monitoring in critically ill patients: Consensus statement from the neurointensive care section of the ESICM. Intensive Care Med 2013; 39: 1337-51
• 67 Bratton SL, Chestnut RM, Ghajar J, McConnell Hammond FF, Harris OA, Hartl R. et al. Guidelines for the management of severe traumatic brain injury. XI. Anesthetics, analgesics, and sedatives. J Neurotrauma 2007; 24 Suppl (Suppl. 01) S71-6
• 68 Zamperetti N, Bellomo R, Defanti CA, Latronico N. Irreversible apnoeic coma 35 years later. Towards a more rigorous definition of brain death? Intensive Care Med 2004; 30: 1715-22
• 69 Kamel H, Betjemann JP, Navi BB, Hegde M, Meisel K, Douglas VC. et al. Diagnostic yield of electroencephalography in the medical and surgical intensive care unit. Neurocrit Care 2013; 19: 336-41
• 70 Hirsch LJ, LaRoche SM, Gaspard N, Gerard E, Svoronos A, Herman ST. et al. American Clinical Neurophysiology Society's Standardized Critical Care EEG Terminology: 2012 version. J Clin Neurophysiol 2013; 30: 1-27
• 71 Young GB, Ives JR, Chapman MG, Mirsattari SM. A comparison of subdermal wire electrodes with collodion-applied disk electrodes in long-term EEG recordings in ICU. Clin Neurophysiol 2006; 117: 1376-9
• 72 Karakis I, Montouris GD, Otis JA, Douglass LM, Jonas R, Velez-Ruiz N. et al. A quick and reliable EEG montage for the detection of seizures in the critical care setting. J Clin Neurophysiol 2010; 27: 100-5
• 73 Toet MC, van der Meij W, de Vries LS, Uiterwaal CS, van Huffelen KC. Comparison between simultaneously recorded amplitude integrated electroencephalogram (cerebral function monitor) and standard electroencephalogram in neonates. Pediatrics 2002; 109: 772-9
• 74 Young GB, Jordan KG, Doig GS. An assessment of nonconvulsive seizures in the intensive care unit using continuous EEG monitoring: An investigation of variables associated with mortality. Neurology 1996; 47: 83-9
• 75 Laccheo I, Sonmezturk H, Bhatt AB, Tomycz L, Shi Y, Ringel M. et al. Non-convulsive status epilepticus and non-convulsive seizures in neurological ICU patients. Neurocrit Care 2015; 22: 202-11
• 76 Claassen J, Mayer SA, Kowalski RG, Emerson RG, Hirsch LJ. Detection of electrographic seizures with continuous EEG monitoring in critically ill patients. Neurology 2004; 62: 1743-8
• 77 Krishnamurthy KB, Drislane FW. Depth of EEG suppression and outcome in barbiturate anesthetic treatment for refractory status epilepticus. Epilepsia 1999; 40: 759-62
• 78 Friberg H, Westhall E, Rosén I, Rundgren M, Nielsen N, Cronberg T. Clinical review: Continuous and simplified electroencephalography to monitor brain recovery after cardiac arrest. Crit Care 2013; 17: 233
• 79 Rossetti AO, Urbano LA, Delodder F, Kaplan PW, Oddo M. Prognostic value of continuous EEG monitoring during therapeutic hypothermia after cardiac arrest. Crit Care 2010; 14: R173
• 80 Rundgren M, Westhall E, Cronberg T, Rosén I, Friberg H. Continuous amplitude-integrated electroencephalogram predicts outcome in hypothermia-treated cardiac arrest patients. Crit Care Med 2010; 38: 1838-44
• 81 Tzovara A, Rossetti AO, Spierer L, Grivel J, Murray MM, Oddo M. et al. Progression of auditory discrimination based on neural decoding predicts awakening from coma. Brain 2013; 136 (Pt 1) 81-9
• 82 Vespa PM, Nuwer MR, Juhász C, Alexander M, Nenov V, Martin N. et al. Early detection of vasospasm after acute subarachnoid hemorrhage using continuous EEG ICU monitoring. Electroencephalogr Clin Neurophysiol 1997; 103: 607-15
• 83 Claassen J, Hirsch LJ, Kreiter KT, Du EY, Connolly ES, Emerson RG. et al. Quantitative continuous EEG for detecting delayed cerebral ischemia in patients with poor-grade subarachnoid hemorrhage. Clin Neurophysiol 2004; 115: 2699-710
• 84 Rathakrishnan R, Gotman J, Dubeau F, Angle M. Using continuous electroencephalography in the management of delayed cerebral ischemia following subarachnoid hemorrhage. Neurocrit Care 2011; 14: 152-61
• 85 Finnigan SP, Rose SE, Walsh M, Griffin M, Janke AL, McMahon KL. et al. Correlation of quantitative EEG in acute ischemic stroke with 30-day NIHSS score: comparison with diffusion and perfusion MRI. Stroke 2004; 35: 899-903
• 86 Finnigan SP, Walsh M, Rose SE, Chalk JB. Quantitative EEG indices of sub-acute ischaemic stroke correlate with clinical outcomes. Clin Neurophysiol 2007; 118: 2525-32
• 87 Claassen J, Jetté N, Chum F, Green R, Schmidt M, Choi H. et al. Electrographic seizures and periodic discharges after intracerebral hemorrhage. Neurology 2007; 69: 1356-65
• 88 Oertel M, Kelly DF, Lee JH, Glenn TC, Vespa PM, Martin NA. Metabolic suppressive therapy as a treatment for intracranial hypertension – Why it works and when it fails. Acta Neurochir Suppl 2002; 81: 69-70
• 89 Finelli LA, Achermann P, Borbély AA. Individual ‘fingerprints’ in human sleep EEG topography. Neuropsychopharmacology 2001; 25 (Suppl. 05) Suppl S57-62
• 90 Dahaba AA. Different conditions that could result in the bispectral index indicating an incorrect hypnotic state. Anesth Analg 2005; 101: 765-73
• 91 Gallagher JD. Pacer-induced artifact in the bispectral index during cardiac surgery. Anesthesiology 1999; 90: 636
• 92 Hemmerling TM, Fortier JD. Falsely increased bispectral index values in a series of patients undergoing cardiac surgery using forced-air-warming therapy of the head. Anesth Analg 2002; 95: 322-3
• 93 Kochs E. Electrophysiological monitoring and mild hypothermia. J Neurosurg Anesthesiol 1995; 7: 222-8
• 94 Wu CC, Lin CS, Mok MS. bispectral index monitoring during hypoglycemic coma. J Clin Anesth 2002; 14: 305-6
• 95 Renna M, Handy J, Shah A. Low baseline bispectral Index of the electroencephalogram in patients with dementia. Anesth Analg 2003; 96: 1380-5
• 96 Aimé I, Gayat E, Fermanian C, Cook F, Peuch C, Laloë PA. et al. Effect of age on the comparability of bispectral and state entropy indices during the maintenance of propofol-sufentanil anaesthesia. Br J Anaesth 2012; 108: 638-43
• 97 Davidson AJ, Huang GH, Rebmann CS, Ellery C. Performance of entropy and bispectral index as measures of anaesthesia effect in children of different ages. Br J Anaesth 2005; 95: 674-9
• 98 Kern D, Fourcade O, Mazoit JX, Minville V, Chassery C, Chausseray G. et al. The relationship between bispectral index and endtidal concentration of sevoflurane during anesthesia and recovery in spontaneously ventilating children. Paediatr Anaesth 2007; 17: 249-54
• 99 Sakai T, Singh H, Mi WD, Kudo T, Matsuki A. The effect of ketamine on clinical endpoints of hypnosis and EEG variables during propofol infusion. Acta Anaesthesiol Scand 1999; 43: 212-6
• 100 Barr G, Jakobsson JG, Owall A, Anderson RE. Nitrous oxide does not alter bispectral index: Study with nitrous oxide as sole agent and as an adjunct to i.v. anaesthesia. Br J Anaesth 1999; 82: 827-30
• 101 Messner M, Beese U, Romstöck J, Dinkel M, Tschaikowsky K. The bispectral index declines during neuromuscular block in fully awake persons. Anesth Analg 2003; 97: 488-91
• 102 Liu N, Chazot T, Huybrechts I, Law-Koune JD, Barvais L, Fischler M. The influence of a muscle relaxant bolus on bispectral and datex-ohmeda entropy values during propofol-remifentanil induced loss of consciousness. Anesth Analg 2005; 101: 1713-8