the benefit of neuromuscular blockade in patients with...

Research ArticleThe Benefit of Neuromuscular Blockade in Patients withPostanoxic Myoclonus Otherwise Obscuring ContinuousElectroencephalography (CEEG)

Christopher R Newey1 Alejandro Hornik2 Meziane Guerch3 Anantha Veripuram4

Sushma Yerram1 and Agnieszka Ardelt5

1Department of Neurology University of Missouri 5 Hospital Drive CE 540 Columbia MO 65211 USA2Southern Illinois Healthcare 405 W Jackson Street Carbondale IL 62902 USA3Novant Health Forsyth Medical Center 3333 Silas Creek Parkway Winston-Salem NC 27103 USA4Department of Neurology Texas Tech University Health Sciences Center-El Paso 4615 Alameda Avenue El Paso TX 79905 USA5Department of Neurology The University of Chicago Medicine 5841 S Maryland Drive MC2030 Chicago IL 60637 USA

Correspondence should be addressed to Christopher R Newey neweychealthmissouriedu

Received 30 November 2016 Revised 8 January 2017 Accepted 18 January 2017 Published 6 February 2017

Academic Editor Romergryko G Geocadin

Copyright copy 2017 Christopher R Newey et al This is an open access article distributed under the Creative Commons AttributionLicense which permits unrestricted use distribution and reproduction in any medium provided the original work is properlycited

Introduction Myoclonus status epilepticus is independently associated with poor outcome in coma patients after cardiac arrestDetermining if myoclonus is of cortical origin on continuous electroencephalography (CEEG) can be difficult secondary to themuscle artifact obscuring the underlying CEEG The use of a neuromuscular blocker can be useful in these cases MethodsRetrospective review of CEEG in patients with postanoxic myoclonus who received cisatracurium while being monitoredResults Twelve patients (mean age 533 years 583 male) met inclusion criteria of clinical postanoxic myoclonus The initialCEEG patterns immediately prior to neuromuscular blockade showed myoclonic artifact with continuous slowing (50) burstsuppression with myoclonic artifact (417) and continuous myogenic artifact obscuring CEEG (83) After intravenousadministration of cisatracurium (01mgndash2mg) reduction in artifact improved quality of CEEG recordings in 912 (75) revealingpreviously unrecognized patterns continuous EEG seizures (333) lateralizing slowing (167) burst suppression (167)generalized periodic discharges (83) and in the patient who had an initially uninterpretable CEEG from myogenic artifactcontinuous slowing Conclusion Short-acting neuromuscular blockade is useful in determining background cerebral activity onCEEG otherwise partially or completely obscured by muscle artifact in patients with postanoxic myoclonus Fully understandingbackground cerebral activity is important in prognostication and treatment particularly when there are underlying EEG seizures

1 Introduction

Out-of-hospital cardiac arrest remains a major cause ofmorbidity andmortality with only approximately 50 of car-diopulmonary resuscitation (CPR) attempts restoring spon-taneous circulation [1 2] Of the survivals an estimated 10ndash20 will ever regain meaningful neurologic recovery [1 2]For years neurologists have used the landmark paper byLevy et al to guide prognostication [3] Included in thisprognostication algorithm is myoclonus status epilepticuswhich is typically regarded as predictive of a poor outcomeespecially within the first 24 hours after cardiac arrest [3ndash5]

Myoclonus status epilepticus is a clinical diagnosis andis defined as spontaneous or sound sensitive repetitiveirregular brief jerks of the face and limb for most of the firstday after cardiac resuscitation [4] It may be observed in upto 37 of patients following cardiac resuscitation [4] Withthe increasing use of continuous electroencephalography(CEEG) underlying seizure patterns are being recognized[5] Additionally background CEEG patterns are being rec-ognized as having prognostic value [6ndash8] For example in pa-tients with myoclonus the finding of burst suppression back-groundwith high amplitude polyspikes compared to continu-ous slowing with narrow vertex spike-wave discharges may

HindawiCritical Care Research and PracticeVolume 2017 Article ID 2504058 7 pageshttpsdoiorg10115520172504058

2 Critical Care Research and Practice

have worse prognosis [8] However the underlying cerebralactivity can be difficult to interpret given the myogenicartifact that occurs with myoclonus obscuring the underly-ing CEEG background [9] Additionally recording uninter-pretableCEEGcan be costly to the healthcare system [10]Theuse of a short-acting neuromuscular blocker in these patientscan be useful for identifying background cerebral activity andmay ultimately limit the duration of recording [11]

The purpose of this study was to evaluate change in qual-ity of CEEG recording following neuromuscular blockade inpatients admitted with cardiac arrest

2 Methods

21 Patients We retrospectively reviewed consecutive chartsof postcardiac arrest patients over a 24-month period admit-ted to an academic medical center Patients were identifiedfor this study through the EEG database and neurocriticalcare consultation listThe patients were originally admitted incoma from anoxic brain injury Patients were included in thisstudy if they developed postanoxic myoclonus and were sub-sequently monitored on CEEG and received cisatracuriumduring their CEEGmonitoring All patients were normother-mic during CEEG recording This study was exempted fromapproval by the institutional review board because all subjectswere deceased and the study analyzes data obtained as part ofroutine clinical practice

22 Data Acquisition Deidentified data were abstractedfrom the medical records from clinical notes medicationlogs imaging and diagnostic studies and laboratory

CEEG was recorded using 21 electrodes placed accordingto the International 10ndash20 System by certified EEG technol-ogists and interpreted by board-certified electroencephalog-raphers Unless noted otherwise CEEG was recorded in 15-second epochs using bitemporal montage at sensitivity of 5ndash7 uVmm Filters were set at 1 Hz (low frequency) and 70Hz(high frequency)The60Hznotchwas used CEEGwas notedto be partially or completely obscured bymyogenic artifact Ifpartially obscured the CEEG was reviewed for the followingpatterns continuous or lateralized slow activity generalizedperiodic discharge lateralized periodic discharges (histor-ically termed periodic lateralized epileptiform discharges(PLEDs)) burst suppression andor EEG seizures andorstatus epilepticus CEEG seizures were defined as evolvingrhythms in frequency distribution andor morphology at3Hz or greater for more than 10-second duration Noncon-vulsive status epilepticus was defined as continuous ictalpattern lasting gt 30 minutes or ictal pattern present in morethan 50 of 1 hour of CEEG

23 Cisatracurium Administration Protocol Prior to admin-istration of cisatracurium the respiratory rate and tidal vol-ume were adjusted to maintain the minute ventilation Seda-tion if needed was provided with fentanyl infusion Onceminute ventilation stabilized cisatracurium was adminis-tered at a dose of 01ndash2mgkg while monitoring the CEEGRepeat dosing was provided if myogenic artifact was stillnoted on CEEG

Table 1 Patient characteristics

Total patients (119899) 12Age (average range yrs) 5325 28 78Male (119899 ) 7 583Past medical history (119899 )HTN 6 500DMII 1 83HLD 1 83CKD 1 83CAD 7 583Cancer 4 333Sepsis 2 167

Type of arrest (119899 )PEAasystole 10 833VFibVTach 2 167

CAD coronary artery disease CKD chronic kidney disease DMII diabetesmellitus type II HLD hyperlipidemia HTN hypertension 119899 number PEApulseless electrical activity VFib ventricular fibrillation VTach ventriculartachycardia yrs years

24 Data Interpretation Two reviewers (a neurologist and anepileptologist) blindly evaluated the CEEG tracings CEEGwas reviewed for initial frequencies prior to cisatracuriumand frequencies after cisatracurium administration Inter-rater agreement was then calculated For comparison withinoneCEEG the high frequency filter was adjusted to 70 50 3015 and 5Hz before and after cisatracurium administration

3 Results

31 Patient Characteristics Data was collected on twelvepatients with an average age of 5325 years (range 28ndash78 years) The majority were males (583) with a his-tory of hypertension (50) andor coronary artery disease(583) The majority of arrests were pulseless electricalarrest (PEA)asystole (833) while ventricular fibrillation(VFib)ventricular tachycardia (VTach) arrests accounted for167 All twelve patients expired in the hospital from with-drawal of life sustaining treatment Patient characteristics areshown in Table 1

32 EEG Characteristics Prior to neuromuscular blockadethe CEEG was interpreted as continuous slowing or burstsuppression (119899 = 11 Table 2) The CEEG in one patient wascompletely obscured from myogenic artifact (Figure 1(a))The interrater agreement of reduction in myogenic artifactallowing for better visualization of underlying cerebral activ-ity was ldquoperfectrdquo (ie kapp = 100) between these CEEGrecordings ldquoPerfectrdquo (ie kappa = 100) interrater agreementwas observed with precisatracurium CEEG interpretation

After administration of cisatracurium the interpretationof the CEEG was adjusted in nine patients In five patientsthe underlying EEG patterns were then recognized as eitherlateralized slowing burst suppression or generalized peri-odic discharges The one patient with obscured CEEG from

Critical Care Research and Practice 3

Before cisatracurium After cisatracurium

(a)


(b)


(c)

Figure 1 Effect of cisatracurium on continuous electroencephalography (CEEG) (a)The CEEG is completely obscured bymyogenic artifactAfter neuromuscular blockade generalized continuous slowing is seen (b) Myogenic artifact obscured the CEEG After neuromuscularblockade generalized slowing along with lateralized right slowing is seen (c) Rhythmic myogenic artifact partially obscured the CEEG Afterneuromuscular blockade 3Hz generalized periodic discharges were seen consistent with nonconvulsive status epilepticus

Table 2 CEEG characteristics before and after neuromuscularblockade

Before neuromuscular blockade 119873 Continuous slowing +minusmyogenicartifact 6 500

Burst suppression +minusmyogenic artifact 5 417Myogenic artifact obscuring EEG 1 83After neuromuscular blockade 119873 Change in CEEG interpretation 9 750Patterns

EEG seizure 3 333Lateralized slowing 2 167Burst suppression 2 167Generalized periodic discharges 1 83Continuous slowing (obscured EEG) 1 83

EEG electroencephalography119873 number

myogenic artifact was noted to have generalized continuousslowing Postcisatracurium interrater agreement was ldquoper-fectrdquo (ie kappa = 100) for identifying lateralized slowingburst suppression and generalized periodic discharges How-ever interrater agreement was only ldquomoderaterdquo for classifyingseizure (ie kappa = 0412) and generalized continuousslowing (ie kappa = 0471) Figure 1(b) is a representativeCEEG showing the continuous slowing with lateralized rightslowing In three patients underlying CEEG seizure activitywas noted Representative CEEG is shown in Figure 1(c) TheCEEG patterns are shown in Table 2

For comparison adjusting the high frequency filters ofthe CEEG in a patient with myogenic artifact shows that thefaster myogenic artifact can be removed (Figures 2(a)ndash2(e))but at the expense of losing faster frequencies (Figure 2(f))This patient had asymmetric burst suppression (decreasedleft hemisphere) that was not well appreciated with filteradjustment


(a) (b)

(c) (d)

(e) (f)

Figure 2 Effect of filtering continuous electroencephalography (CEEG) compared to cisatracurium CEEG is partially obscured bymyogenicartifact filtered at (a) 70Hz (b) 50Hz (c) 30Hz (d) 15Hz and (e) 5Hz compared to neuromuscular blockade (f)This patient had asymmetricburst suppression (decreased left hemisphere)

4 Discussion

Determining cortical origin of myoclonus and backgroundcerebral activity with CEEG can be difficult secondary tomuscle artifact We have shown in this study that theuse of neuromuscular blockade in patients with postanoxicmyoclonus is useful for identifying the background cerebralactivity

Myoclonic status epilepticus has historically been inde-pendently associated with poor outcome in coma patientsafter cardiac arrest [3 4] Recently reports have shown thatpatients with postanoxic myoclonus can have good outcomes[12] In a study by Bouwes et al 12 of the patients withposthypoxic myoclonus had good neurological outcomesdefined as Glasgow Outcome Scale (GOS) of 4 or 5 [12] EEGmay be useful to determinewhomay have favorable outcome

Background activity on the CEEG has also been shownto have prognostic significance Rossetti et al studied 34consecutive comatose patients treatedwith hypothermia aftercardiac arrest [13] Nonreactive background on CEEG wasseen in 1215 (75) of nonsurvivors versus 019 (0) insurvivors [13] Similarly discontinuous ldquoburst suppressionrdquoactivity and EEG seizures with absent backgrounds were seenin in 1115 (73) and 715 (47) respectively in nonsurvivorscompared to 019 in survivors [13] No improvement inbackground reactivity or seizuresepileptiform dischargeswere seen once rewarmed [13] All survivors had back-ground CEEG reactivity and majority (1419 74) had afavorable outcome of cerebral performance score (CPC) 1

or 2 [14] Routine EEGs of rewarmed comatose patientsin the Targeted Temperature Management trial showed var-ious patterns highly malignant (suppression suppressionwith periodic discharges and burst suppression) malignant(periodic or rhythmic patterns pathological or nonreactivebackground) and benign (absence of malignant features)[15] 37 of patients had a highly malignant EEG patternand all had a poor outcome (CPC of 3ndash5) [15] MalignantEEG patterns had low specificity to predict poor prognosis(48) but specificity increased if 2 or more malignant EEGpatterns were present [15] A benign EEG pattern was foundin 1 of patients with a poor outcome [15] Similarly Elmeret al found that postanoxic patients with myoclonus whohave burst suppression background (ie pattern 1) had worseprognosis compared to those with a continuous background(ie pattern 2) [8] Importantly pattern 1 was found in 74of the patients [8] Of the patients who had pattern 1 no onesurvived and only 50 of those who had pattern 2 survived[8] Collectively these studies highlight the importance ofaccurate interpretation of background cerebral reactivity onCEEG Despite these results none of the patients in our seriessurvived to hospital discharge This finding highlights thechallenges of neurological prognostication after cardiac arrestand the self-fulfilling prophecy particularly since no indexpredicts poor neurological outcome with absolute certainty[16]

Myogenic artifact can obscure the CEEG making itchallenging to interpret the CEEG completely and thusaccurately Adjusting filters has been one method of reducing


the artifact However this practice can alter the underlyingEEG activity as we have shown Algorithms have been createdto remove themyogenic artifact [17] It is still uncertainwhichalgorithm performs optimally in a controlled environment[17] The ICU is an environment with multiple sourcesof artifact which can make algorithms less faithful [17ndash19] Accurately interpreting the background CEEG activ-ity is important [8 13ndash15] Neuromuscular blockade canbe used to reduce myogenic artifact allowing for clearervisualization of the underlying cerebral activity as we havedemonstrated

Whether aggressive treatment of myoclonus or CEEGseizures changes long-term outcomes is unclear Seizuresare common postcardiac arrest In a review of our CEEGdatabase electrographic seizures occur in 267 of patientsmonitored with CEEG after anoxic injury (unpublished dataChristopher R Newey) In the study by Bouwes et alsomatosensory evoked potentials (SSEP) and EEG were usedto determine cortical or subcortical nature of the myoclonus[12] Patient outcome was not correlated to origin of themyoclonus and was considered good outcome in 12 [12] Incontrast a small study fromCincinnati found seizures in 33of its cardiac arrest patients (11 of 33) with 9 of these patientsexpiring before discharge [20]None survived by 30 days [20]Similarly all patients with seizures in a cohort from MayoClinic also had poor outcome [21] Likewise 94 of patientswith epileptiform activity from a cohort from the Universityof Pennsylvania had poor neurologic outcome or death atdischarge [22]

Recognizing that patients with myoclonus can havegood neurological outcomes and knowing that seizures arecommonly identified on CEEG aggressive treatment of theseizure seems reasonable andmay be a source for therapeuticopportunity to improve outcome [23] The use of neuro-muscular blocker on CEEG obscured by myogenic artifactcan allow for recognition of cortical or subcortical origin ofmyoclonus andor recognition of underlying seizure activityon CEEG

Many centers have limited resources (personnel andequipment) and may have limitations with CEEG monitor-ing of cardiac arrest patients In a study of cardiac arrestpatients who underwent therapeutic hypothermia before andafter CEEG monitoring protocol 91 did not have CEEGby protocol and 62 patients had CEEG by protocol [10]In those 91 patients before CEEG protocol 19 patients hadroutine EEGs and 4 had CEEG at discretion of the attendingphysician [10]Themean estimatedCEEGcharges for the pre-CEEG protocol cohort was $157159 per patient compared to$421493 per patient after CEEG protocol monitoring duringtherapeutic hypothermia [10] Despite the addition of CEEGmonitoring to the therapeutic hypothermia protocol therewas no difference in mortality [10] Additionally Alvarez etal compared two 20-minute EEGs randomly extracted fromaCEEG recording during therapeutic hypothermia and duringnormothermia [24]Thirty-four recordings were studied andthey found agreement of 971 for background discontinuityand reactivity and 941 for epileptiform activity in thera-peutic hypothermia [24] In normothermia there were nodiscrepancies [24] Our study complements these studies by

highlighting the ability to obtain background CEEG patternswith the use of a neuromuscular blocker which can limit thetime needed to monitor postcardiac arrest patients The abil-ity to review background CEEG pattern early in the courseof recording in cases of myoclonic artifact is cost-effectiveand has practical implications particularly if CEEG resourcesare limited

Cisatracurium was chosen for neuromuscular blockadein our patient population It has a unique mechanismof action for degradation via Hoffman elimination [25]It is metabolized to laudanosine and ultimately excretedin the urine [26] Since it does not rely on liver func-tion for metabolism it is ideally suited for use in post-cardiac arrest patients who may have liver dysfunction[27] The recommended bolus is 01ndash02mgkg with anonset of 90ndash120 seconds and duration of action of 45ndash75 minutes [27] Prior to administration of neuromuscu-lar blockade the ventilator was adjusted to volume con-trol ventilation followed by adjustment in respiratory rateand tidal volume to maintain minute ventilation Sedationincluded fentanyl infusion Benzodiazepines and propofolwere held secondary to their known effects on CEEG andconfounding neurological prognosis [5 28] Additionally thehypotension that may occur with these agents particularlyin the critically ill influenced the decision to use fentanylalone [29]

This study is inherently limited by being a retrospec-tive review of patients Additionally self-fulfilling prophecycannot be excluded from studies such as this It is notknown if patients with seizures would have good neurologicaloutcomes if treated aggressively The clinical recognitionof status myoclonus has been suggested to be predictiveof poor outcome [4] It is currently part of the AANpractice parameter guidelines as level B evidence supportingpoor prognosis [4] As such all patients in this study hadwithdrawal of life sustaining treatment Also this study wasnot designed to review the cost analysis from decreasedduration of CEEG after the use of cisatracurium Theseshould be studied further in a large randomized controlledtrial We found variability in CEEG interpretation espe-cially with classifying seizures or continuous slowing Theinterrater agreement for each of these was moderate CEEGterminology has been evolving [30] Interrater agreementin interpreting CEEG especially with periodic dischargeshas been a recognized problem [31 32] Board certificationin Clinical Neurophysiology as well as the use of quan-titative EEG has been associated with improved interrateragreement [33 34] As we learn more about the prognosticvalue of underlying background on CEEG it is impor-tant that the interrater agreement for CEEG interpretationimproves

In conclusion the use of neuromuscular blockade inpatients with postanoxic myoclonus who are monitored onCEEG can be useful in identifying the background corticalactivity Accurately identifying background activity is knownto be important in prognostication Future studies shouldevaluate the cost analysis of continuous EEG recording withmyogenic artifact with and without neuromuscular blockadein patients with postanoxic myoclonus


Competing Interests

The authors declare that they have no competing interests

Authorsrsquo Contributions

All authors contributed equally to the writing of the case andformatting the images

References

[1] M A Koenig P W Kaplan and N V Thakor ldquoClinical neuro-physiologic monitoring and brain injury from cardiac arrestrdquoNeurologic Clinics vol 24 no 1 pp 89ndash106 2006

[2] P Safar ldquoCerebral resuscitation after cardiac arrest a reviewrdquoCirculation vol 74 no 6 pp 138ndash152 1986

[3] D E Levy J J Caronna B H Singer R H Lapinski H Fryd-man and F Plum ldquoPredicting outcome from hypoxic-lschemiccomardquoThe Journal of theAmericanMedical Association vol 253no 10 pp 1420ndash1426 1985

[4] E F MWijdicks J E Parisi and FW Sharbrough ldquoPrognosticvalue of myoclonus status in comatose survivors of cardiacarrestrdquo Annals of Neurology vol 35 no 2 pp 239ndash243 1994

[5] E F M Wijdicks A Hijdra G B Young C L Bassetti and SWiebe ldquoPractice parameter Prediction of outcome in comatosesurvivors after cardiopulmonary resuscitation (an evidence-based review) Report of the Quality Standards Subcommitteeof the American Academy of NeurologyrdquoNeurology vol 67 no2 pp 203ndash210 2006

[6] A Sivaraju E J Gilmore C R Wira et al ldquoPrognostication ofpost-cardiac arrest coma early clinical and electroencephalo-graphic predictors of outcomerdquo Intensive Care Medicine vol 41no 7 pp 1264ndash1272 2015

[7] B Foreman J Claassen K A Khaled et al ldquoGeneralizedperiodic discharges in the critically ill a case-control study of200 patientsrdquo Neurology vol 79 no 19 pp 1951ndash1960 2012

[8] J Elmer J C Rittenberger J Faro et al ldquoClinically distinctelectroencephalographic phenotypes of early myoclonus aftercardiac arrestrdquo Annals of Neurology vol 80 no 2 pp 175ndash1842016

[9] V Alvarez A Sierra-Marcos M Oddo and A O RossettildquoYield of intermittent versus continuous EEG in comatosesurvivors of cardiac arrest treated with hypothermiardquo CriticalCare vol 17 no 5 article R190 2013

[10] A Z Crepeau J E Fugate J Mandrekar et al ldquoValue analysisof continuous EEG in patients during therapeutic hypothermiaafter cardiac arrestrdquo Resuscitation vol 85 no 6 pp 785ndash7892014

[11] D Crippen ldquoRole of bedside electroencephalography in theadult intensive care unit during therapeutic neuromuscularblockaderdquo Critical Care vol 1 pp S58ndashS61 1997

[12] A Bouwes D van Poppelen J H T M Koelman et al ldquoAcuteposthypoxic myoclonus after cardiopulmonary resuscitationrdquoBMC Neurology vol 12 article no 63 2012

[13] A O Rossetti L A Urbano F Delodder P W Kaplan and MOddo ldquoPrognostic value of continuous EEGmonitoring duringtherapeutic hypothermia after cardiac arrestrdquo Critical Care vol14 article R173 2010

[14] A O Rossetti M Oddo G Logroscino and P W KaplanldquoPrognostication after cardiac arrest and hypothermia a

prospective studyrdquo Annals of Neurology vol 67 no 3 pp 301ndash307 2010

[15] E Westhall A O Rossetti A-F Van Rootselaar et al ldquoStan-dardized EEG interpretation accurately predicts prognosis aftercardiac arrestrdquo Neurology vol 86 no 16 pp 1482ndash1490 2016

[16] C Sandroni and R G Geocadin ldquoNeurological prognosticationafter cardiac arrestrdquoCurrent Opinion in Critical Care vol 21 no3 pp 209ndash214 2015

[17] J A Uriguen and B Garcia-Zapirain ldquoEEG artifact removalmdashstate-of-the-art and guidelinesrdquo Journal of Neural Engineeringvol 12 no 3 Article ID 031001 2015

[18] V Alvarez and A O Rossetti ldquoClinical use of EEG in the ICUtechnical settingrdquo Journal of Clinical Neurophysiology vol 32no 6 pp 481ndash485 2015

[19] A Nonclercq and P Mathys ldquoQuantification of motion artifactrejection due to active electrodes and driven-right-leg circuitin spike detection algorithmsrdquo IEEE Transactions on BiomedicalEngineering vol 57 no 11 pp 2746ndash2752 2010

[20] W A Knight KW Hart O M Adeoye et al ldquoThe incidence ofseizures in patients undergoing therapeutic hypothermia afterresuscitation fromcardiac arrestrdquoEpilepsy Research vol 106 no3 pp 396ndash402 2013

[21] A Z Crepeau A A Rabinstein J E Fugate et al ldquoContinuousEEG in therapeutic hypothermia after cardiac arrest prognosticand clinical valuerdquo Neurology vol 80 no 4 pp 339ndash344 2013

[22] R Mani S E Schmitt M Mazer M E Putt and D FGaieski ldquoThe frequency and timing of epileptiform activityon continuous electroencephalogram in comatose post-cardiacarrest syndrome patients treated with therapeutic hypother-miardquo Resuscitation vol 83 no 7 pp 840ndash847 2012

[23] R G Geocadin and E K Ritzl ldquoSeizures and status epilepticusin post cardiac arrest syndrome therapeutic opportunities toimprove outcomeor basis towithhold life sustaining therapiesrdquoResuscitation vol 83 no 7 pp 791ndash792 2012

[24] V Alvarez A Sierra-Marcos M Oddo and A O RossettildquoYield of intermittent versus continuous EEG in comatosesurvivors of cardiac arrest treated with hypothermiardquo CriticalCare vol 17 no 5 article no R190 2013

[25] R M Welch A Brown J Ravitch and R Dahl ldquoThe invitro degradation of cisatracurium the R cis-R1015840-isomer ofatracurium in human and rat plasmardquo Clinical PharmacologyandTherapeutics vol 58 no 2 pp 132ndash142 1995

[26] E W Moore and J M Hunter ldquoThe new neuromuscularblocking agents do they offer any advantagesrdquo British Journalof Anaesthesia vol 87 no 6 pp 912ndash925 2001

[27] GM Brophy T Human and L Shutter ldquoEmergency neurolog-ical life support pharmacotherapyrdquo Neurocritical Care vol 23pp 48ndash68 2015

[28] H Arif and L J Hirsch ldquoTreatment of status epilepticusrdquoSeminars in Neurology vol 28 no 3 pp 342ndash354 2008

[29] G M Keating ldquoDexmedetomidine a review of its use forsedation in the intensive care settingrdquo Drugs vol 75 no 10 pp1119ndash1130 2015

[30] N Gaspard L J Hirsch S M LaRoche C D Hahn and MBrandon ldquoInterrater agreement for critical care EEG terminol-ogyrdquo Epilepsia vol 55 no 9 pp 1366ndash1373 2014

[31] B Foreman A Mahulikar P Tadi et al ldquoGeneralized periodicdischarges and lsquotriphasic wavesrsquo a blinded evaluation of inter-rater agreement and clinical significancerdquo Clinical Neurophysi-ology vol 127 no 2 pp 1073ndash1080 2016


[32] J J Halford D Shiau J A Desrochers et al ldquoInter-rater agree-ment on identification of electrographic seizures and periodicdischarges in ICU EEG recordingsrdquo Clinical Neurophysiologyvol 126 no 9 pp 1661ndash1669 2015

[33] J Halford A Arain G Kalamangalam et al ldquoCharacteristics ofEEG interpreters associated with higher inter-rater agreementrdquoJournal of Clinical Neurophysiology 2016

[34] N Dericioglu E Yetim D F Bas et al ldquoNon-expert use ofquantitative EEG displays for seizure identification in the adultneuro-intensive care unitrdquo Epilepsy Research vol 109 no 1 pp48ndash56 2015

Submit your manuscripts athttpswwwhindawicom

Stem CellsInternational

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014


MEDIATORSINFLAMMATION

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Behavioural Neurology

EndocrinologyInternational Journal of



Disease Markers


BioMed Research International

OncologyJournal of



Oxidative Medicine and Cellular Longevity


PPAR Research

The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014

Immunology ResearchHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal of

ObesityJournal of



Computational and Mathematical Methods in Medicine

OphthalmologyJournal of


Diabetes ResearchJournal of



Research and TreatmentAIDS


Gastroenterology Research and Practice


Parkinsonrsquos Disease

Evidence-Based Complementary and Alternative Medicine

Volume 2014Hindawi Publishing Corporationhttpwwwhindawicom


have worse prognosis [8] However the underlying cerebralactivity can be difficult to interpret given the myogenicartifact that occurs with myoclonus obscuring the underly-ing CEEG background [9] Additionally recording uninter-pretableCEEGcan be costly to the healthcare system [10]Theuse of a short-acting neuromuscular blocker in these patientscan be useful for identifying background cerebral activity andmay ultimately limit the duration of recording [11]

The purpose of this study was to evaluate change in qual-ity of CEEG recording following neuromuscular blockade inpatients admitted with cardiac arrest

2 Methods

21 Patients We retrospectively reviewed consecutive chartsof postcardiac arrest patients over a 24-month period admit-ted to an academic medical center Patients were identifiedfor this study through the EEG database and neurocriticalcare consultation listThe patients were originally admitted incoma from anoxic brain injury Patients were included in thisstudy if they developed postanoxic myoclonus and were sub-sequently monitored on CEEG and received cisatracuriumduring their CEEGmonitoring All patients were normother-mic during CEEG recording This study was exempted fromapproval by the institutional review board because all subjectswere deceased and the study analyzes data obtained as part ofroutine clinical practice

22 Data Acquisition Deidentified data were abstractedfrom the medical records from clinical notes medicationlogs imaging and diagnostic studies and laboratory

CEEG was recorded using 21 electrodes placed accordingto the International 10ndash20 System by certified EEG technol-ogists and interpreted by board-certified electroencephalog-raphers Unless noted otherwise CEEG was recorded in 15-second epochs using bitemporal montage at sensitivity of 5ndash7 uVmm Filters were set at 1 Hz (low frequency) and 70Hz(high frequency)The60Hznotchwas used CEEGwas notedto be partially or completely obscured bymyogenic artifact Ifpartially obscured the CEEG was reviewed for the followingpatterns continuous or lateralized slow activity generalizedperiodic discharge lateralized periodic discharges (histor-ically termed periodic lateralized epileptiform discharges(PLEDs)) burst suppression andor EEG seizures andorstatus epilepticus CEEG seizures were defined as evolvingrhythms in frequency distribution andor morphology at3Hz or greater for more than 10-second duration Noncon-vulsive status epilepticus was defined as continuous ictalpattern lasting gt 30 minutes or ictal pattern present in morethan 50 of 1 hour of CEEG

23 Cisatracurium Administration Protocol Prior to admin-istration of cisatracurium the respiratory rate and tidal vol-ume were adjusted to maintain the minute ventilation Seda-tion if needed was provided with fentanyl infusion Onceminute ventilation stabilized cisatracurium was adminis-tered at a dose of 01ndash2mgkg while monitoring the CEEGRepeat dosing was provided if myogenic artifact was stillnoted on CEEG

Table 1 Patient characteristics

Total patients (119899) 12Age (average range yrs) 5325 28 78Male (119899 ) 7 583Past medical history (119899 )HTN 6 500DMII 1 83HLD 1 83CKD 1 83CAD 7 583Cancer 4 333Sepsis 2 167

Type of arrest (119899 )PEAasystole 10 833VFibVTach 2 167

CAD coronary artery disease CKD chronic kidney disease DMII diabetesmellitus type II HLD hyperlipidemia HTN hypertension 119899 number PEApulseless electrical activity VFib ventricular fibrillation VTach ventriculartachycardia yrs years

24 Data Interpretation Two reviewers (a neurologist and anepileptologist) blindly evaluated the CEEG tracings CEEGwas reviewed for initial frequencies prior to cisatracuriumand frequencies after cisatracurium administration Inter-rater agreement was then calculated For comparison withinoneCEEG the high frequency filter was adjusted to 70 50 3015 and 5Hz before and after cisatracurium administration

3 Results

31 Patient Characteristics Data was collected on twelvepatients with an average age of 5325 years (range 28ndash78 years) The majority were males (583) with a his-tory of hypertension (50) andor coronary artery disease(583) The majority of arrests were pulseless electricalarrest (PEA)asystole (833) while ventricular fibrillation(VFib)ventricular tachycardia (VTach) arrests accounted for167 All twelve patients expired in the hospital from with-drawal of life sustaining treatment Patient characteristics areshown in Table 1

32 EEG Characteristics Prior to neuromuscular blockadethe CEEG was interpreted as continuous slowing or burstsuppression (119899 = 11 Table 2) The CEEG in one patient wascompletely obscured from myogenic artifact (Figure 1(a))The interrater agreement of reduction in myogenic artifactallowing for better visualization of underlying cerebral activ-ity was ldquoperfectrdquo (ie kapp = 100) between these CEEGrecordings ldquoPerfectrdquo (ie kappa = 100) interrater agreementwas observed with precisatracurium CEEG interpretation

After administration of cisatracurium the interpretationof the CEEG was adjusted in nine patients In five patientsthe underlying EEG patterns were then recognized as eitherlateralized slowing burst suppression or generalized peri-odic discharges The one patient with obscured CEEG from



(a)


(b)


(c)










(a) (b)

(c) (d)

(e) (f)


4 Discussion
















Competing Interests




References










































of






Disease Markers



OncologyJournal of





PPAR Research



Journal of

ObesityJournal of


















(a)


(b)


(c)










(a) (b)

(c) (d)

(e) (f)


4 Discussion
















Competing Interests




References










































of






Disease Markers



OncologyJournal of





PPAR Research



Journal of

ObesityJournal of

















(a) (b)

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References










































of






Disease Markers



OncologyJournal of





PPAR Research



Journal of

ObesityJournal of

























of






Disease Markers



OncologyJournal of





PPAR Research



Journal of

ObesityJournal of
















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