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ARTICLES: N. S. Abend, A. Topjian, R. Ichord, S. T. Herman, M. Helfaer, M. Donnelly, V. Nadkarni, D. J. Dlugos, and R. R. Clancy Electroencephalographic monitoring during hypothermia after pediatric cardiac arrest Neurology 2009; 72: 1931-1940 [Abstract] [Full text] [PDF]

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Electroencephalographic monitoring during hypothermia after pediatric cardiac arrest

Jenna M. Klotz, BS, MS, Natalia R. Carvalho , Donald L. Gilbert, MD, MS   (17 August 2009)

Reply from the authors

Nicholas S. Abend, Alexis Topjian, Rebecca Ichord, Susan T. Herman, Mark Helfaer, Maureen Donnelly, Vinay Nadkarni, Dennis J. Dlugos, Robert R. Clancy   (17 August 2009)

Electroencephalographic monitoring during hypothermia after pediatric cardiac arrest 17 August 2009
Jenna M. Klotz, BS, MS, niversity of Cincinnati School of Medicine Cincinnati, OH 45229, Natalia R. Carvalho , Donald L. Gilbert, MD, MS Send Correspondence to journal: Re: Electroencephalographic monitoring during hypothermia after pediatric cardiac arrest klotzjm{at}email.uc.edu Jenna M. Klotz, BS, MS, et al.	Abend et al. demonstrate the safety and feasibility of continuous EEG monitoring in pediatric cardiac arrest patients undergoing therapeutic hypothermia. They suggest that EEG findings may prognosticate outcomes and influence treatment decisions. [1] However, we suggest an alternative view of their data. As shown in Table 1, children whose resuscitation lasted five minutes or less tended to have better outcomes than those with longer CPR duration. To compare predictive value of CPR duration in the 18 (of 19) children where this was reported to subsequent initial EEG findings, we dichotomized CPR duration, initial EEG findings, and outcome. CPR duration was categorized as < or = 5 minutes and > 5 minutes. Although the American Heart Association states that discontinuation of resuscitative efforts may be considered at 10 minutes [2], we selected 5 minutes as our threshold because it appeared to better account for outcomes and is supported by another pediatric case series. [3] Based on the authors' classification, initial EEG findings were considered abnormal if epileptiform discharges or electrographic seizures were present or if beta activity was absent. We stratified our outcomes as "good" for return to baseline or mildly abnormal short-term outcomes and as "bad" for death or new severe neurologic impairment. The median CPR duration was 4 minutes for those with good outcomes, compared to 18.5 minutes CPR duration for children with bad outcomes (Wilcoxon p=.019). Applying the 5-minute rule correctly identifies 7 of 8 with good outcomes and 9 of 10 with bad outcomes. Stratifying the same 18 children by the authors' normal and abnormal initial EEG findings also correctly identifies 7 of 8 with good outcomes and 9 of 10 with bad outcomes (Fisher Exact p=.0029 for both methods). The etiologies of the four non-overlapping misclassifications of both CPR duration and EEG findings are instructive: subject 1 (long CPR, good EEG, good outcome) had ventricular tachycardia, not asystole; subject 11 (CPR right at the 5 minute threshold, bad EEG, bad outcome) had anaphylaxis; subject 10 (long CPR, good EEG, bad outcome) had Trisomy 21; subject 12 (short CPR, bad EEG, "good" outcome) had prior severe multi-factorial encephalopathy and "good" was back to baseline. We suggest that CPR duration nearly always predicts outcome and may be a simpler, more cost-effective method of stratifying pediatric cardiac arrest patients. Because EEG monitoring adds little new information about prognosis in most cases, its use may be selective, not routine. References 1. Abend NS, Topjian A, Ichord R, et al. Electroencephalographic monitoring during hypothermia after pediatric cardiac arrest. Neurology 2009;72:1931-1940. 2. 2005 American Heart Association (AHA) guidelines for cardiopulmonary resuscitation (CPR) and emergency cardiovascular care (ECC) of pediatric and neonatal patients: pediatric basic life support. Pediatrics 2006;117:e989-1004. 3. Akcay A, Baysal SU, Yavuz T. Factors influencing outcome of inpatient pediatric resuscitation. Turkish Journal of Pediatrics 2006;48:313-322. Disclosures: Mr. Klotz reports no disclosures. Ms. Carvalho reports no disclosures. Dr. Gilbert serves on the medical advisory board for the Tourette Syndrome Association; is funded by NIH research grants NS056276, MH078160, MH08185; and receives support from Cincinnati Children’s Hospital Research Foundation, the University of Cincinnati, and the Tourette Syndrome Association.
Reply from the authors 17 August 2009
Nicholas S. Abend, Children's Hospital of Philadelphia 34th Street and Civic Center Blvd, Philadelphia, PA 19104, Alexis Topjian, Rebecca Ichord, Susan T. Herman, Mark Helfaer, Maureen Donnelly, Vinay Nadkarni, Dennis J. Dlugos, Robert R. Clancy Send Correspondence to journal: Re: Reply from the authors abend{at}email.chop.edu Nicholas S. Abend, et al.	Gilbert et al. performed a re-analysis of our data and observed that CPR duration predicted short-term outcome with as similar accuracy as early EEG features in children treated with hypothermia after cardiac arrest. The objective of our investigation was to address the clinical feasibility of conducting continuous EEG monitoring (cEEG) in this setting and describe the occurrence of seizures in this population. Our goal was not to use brief EEG samples as early prognostic indicators. The recent AAN Practice Parameter addressing outcome prediction in comatose adults after cardiac arrest concludes that prognosis should not be based on the characteristics of CPR (including duration) [4] and this recommendation may reasonably be extended to children. We believe EEG features may be prognostically relevant for four reasons: (1) The clinical history is sometimes unclear or unavailable. (2) CPR effects depend on both duration and quality [5], which may vary independently. (3) Both clinical and EEG strategies misclassify some patients, as Dr. Gilbert correctly describes. This suggests that an optimal predictive model may need to take into account multiple types of information. Our data suggest that EEG features may be one useful model component. (4) As new resuscitation algorithms are developed, current clinical predictors may prove less relevant, necessitating more sophisticated outcome prediction tools. For example, even very long CPR efforts can result in good outcome when cardiopulmonary bypass is initiated early [6]. Dr. Gilbert concludes that "because EEG monitoring added little new information about prognosis in most cases, its use may be selective, not routine." We agree that there are insufficient data to conclude that all patients treated with hypothermia in clinical practice must undergo cEEG. However, cEEG may have utility beyond providing early glimpses of prognosis. Non-convulsive seizures (NCS) were identified in 47% of children reported and the presence of longer NCS or delay to diagnosis has been associated with worse outcome. [7] NCS could lead to ongoing neuronal injury. Early detection and treatment could improve outcome. Equipoise exists because there are incomplete data about the value of combined use of clinical, EEG, and other biomarkers to predict outcomes. Research-based, prospective studies are needed to elucidate their respective roles in large numbers of critically ill patients. These studies should illuminate the potential impact of cEEG in identifying NCS and their early management, in conjunction with other prognostic clinical information such as CPR duration. References 4. Wijdicks EF, Hijdra A, Young GB, Bassetti CL, Wiebe S. Practice parameter: prediction of outcome in comatose survivors after cardiopulmonary resuscitation (an evidence-based review): report of the Quality Standards Subcommittee of the American Academy of Neurology. Neurology 2006;67:203-210. 5. Sutton RM, Niles D, Nysaether J, et al. Quantitative Analysis of CPR Quality During In-Hospital Resuscitation of Older Children and Adolescents. Pediatrics 2009. (Published online July 5, 2009) 6. Morris MC, Ittenbach RF, Godinez RI, et al. Risk factors for mortality in 137 pediatric cardiac intensive care unit patients managed with extracorporeal membrane oxygenation. Crit Care Med 2004;32:1061-1069. 7. 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;47:83-89. Disclosures: Dr. Abend has received a Young Investigators Award from UCB Pharmaceuticals; has received grants from the National EpiFellows Foundation and the University of Pennsylvania Clinical Neuroscience Center. Dr. Topjian has received a grant from the University of Pennsylvania Clinical Trials Center. Dr. Ichord has received a grant from the NIH (Validation of the NIH Stroke Scale in Children) and a consultation fee for participation in Clinical Event Committee for Berlin Heart ventricular assist device trial. Dr. Herman has received consulting fees from GlaxoSmithKline. Dr. Helfaer has received grants from the NIH (Validation of the NIH Stroke Scale in Children) and Genzyme. Dr. Donnelly reports no disclosures. Dr. Nadkarni has received grants from the NIH, Agency for Healthcare Research and Quality, National Highway Safety and Traffic Administration, and Laerdal Foundation for Acute Care Medicine. Dr. Dlugos has received a grant from UCB Pharma (investigator initiated grant). Dr. Clancy has received a grant from the University of Pennsylvania Pediatric Pharmacologic Research Unit and an honorarium from Abbott Laboratories.