Detection of electrographic seizures with continuous EEG monitoring in critically ill patients
J. Claassen, MD, S. A. Mayer, MD, R. G. Kowalski, BS, R. G. Emerson, MD and L. J. Hirsch, MD
From the Division of Critical Care Neurology (Drs. Claassen and Mayer, R.G. Kowalski) and Comprehensive Epilepsy Center (Drs. Claassen, Emerson, and Hirsch), Department of Neurology, College of Physicians and Surgeons, Columbia University, New York.
Address correspondence and reprint requests to Dr. J. Claassen, Division of Critical Care Neurology, Neurologic Institute, 710 W. 168 St., Unit 1, New York, NY 10032
Objective: To identify patients most likely to have seizures documented on continuous EEG (cEEG) monitoring and patients who require more prolonged cEEG to record the first seizure.
Methods: Five hundred seventy consecutive patients who underwent cEEG monitoring over a 6.5-year period
were reviewed for the detection of subclinical seizures or evaluation of unexplained decrease in level of consciousness. Baseline demographic, clinical, and EEG findings were recorded and a multivariate logistic regression analysis performed to identify factors associated with 1) any EEG seizure activity and 2) first seizure detected after >24 hours of monitoring.
Results: Seizures were detected in 19% (n = 110) of patients who underwent cEEG monitoring; the seizures were exclusively nonconvulsive in 92% (n = 101) of these patients. Among patients with seizures, 89% (n = 98 ) were in intensive care units at the time of monitoring.
Electrographic seizures were associated with coma (odds ratio [OR] 7.7, 95% CI 4.2 to 14.2), age <18 years (OR 6.7, 95% CI 2.8 to 16.2), a history of epilepsy (OR 2.7, 95% CI 1.3 to 5.5), and convulsive seizures during the current illness prior to monitoring (OR 2.4, 95% CI 1.4 to 4.3). Seizures were detected within the first 24 hours of cEEG monitoring in 88% of all patients who would eventually have seizures detected by cEEG. In another 5% (n = 6), the first seizure was recorded on monitoring day 2, and in 7% (n = 8 ), the first seizure was detected after 48 hours of monitoring. Comatose patients were more likely to have their first seizure recorded after >24 hours of monitoring (20% vs 5% of noncomatose patients; OR 4.5, p = 0.018 ).
Conclusions: CEEG monitoring detected seizure activity in 19% of patients, and the seizures were almost always nonconvulsive. Coma, age <18 years, a history of epilepsy, and convulsive seizures prior to monitoring were risk factors for electrographic seizures. Comatose patients frequently required >24 hours of monitoring to detect the first electrographic seizure.
Received September 25, 2003. Accepted in final form January 26, 2004.
The authors thank the attendings, fellows, and technicians of the Columbia Comprehensive Epilepsy Center for assistance in performing and interpreting the EEG and the Neuroscience ICU staff for their support of this project.
This article has been cited by other articles:
Archives Neurology / AMA-ASSN
E. Carrera, J. Claassen, M. Oddo, R. G. Emerson, S. A. Mayer, and L. J. Hirsch
Continuous Electroencephalographic Monitoring in Critically Ill Patients With Central Nervous System Infections
Arch Neurol, December 1, 2008; 65(12): 1612 - 1618.
Neurology Page
N. K. Sethi, J. Torgovnick, E. Arsura, P. K. Sethi, G. L. Krauss, J. Claassen, N. Jette, M. Schmidt, H. Choi, J. Jirsch, et al.
Re: Electrographic seizures and periodic discharges after intracerebral hemorrhage.
Neurology, November 4, 2008; 71(19): 1554 - 1554.
Journal of Intensive Care Medicine
D. J. Costello and A. J. Cole
Treatment of Acute Seizures and Status Epilepticus
J Intensive Care Med, November 1, 2007; 22(6): 319 - 347.
Neurology (Archives)
J. Claassen, N. Jette, F. Chum, R. Green, M. Schmidt, H. Choi, J. Jirsch, J. A. Frontera, E. S. Connolly, R. G. Emerson, et al.
Electrographic seizures and periodic discharges after intracerebral hemorrhage
Neurology, September 25, 2007; 69(13): 1356 - 1365.
Neurology Archieves
N. Jette, J. Claassen, R. G. Emerson, and L. J. Hirsch
Frequency and Predictors of Nonconvulsive Seizures During Continuous Electroencephalographic Monitoring in Critically Ill Children
Arch Neurol, December 1, 2006; 63(12): 1750 - 1755.
Journal of Pharmacology
A. J. Williams, C. C. Bautista, R.-W. Chen, J. R. Dave, X.-C. M. Lu, F. C. Tortella, and J. A. Hartings
Evaluation of Gabapentin and Ethosuximide for Treatment of Acute Nonconvulsive Seizures following Ischemic Brain Injury in Rats
J. Pharmacol. Exp. Ther., September 1, 2006; 318(3): 947 - 955.
Neurology
E. Carrera, P. Michel, P. -A. Despland, M. Maeder-Ingvar, C. Ruffieux, D. Debatisse, J. Ghika, G. Devuyst, and J. Bogousslavsky
Continuous assessment of electrical epileptic activity in acute stroke.
Neurology, July 11, 2006; 67(1): 99 - 104.
New England Journal of Medicine
J. I. Suarez, R. W. Tarr, and W. R. Selman
Aneurysmal Subarachnoid Hemorrhage
N. Engl. J. Med., January 26, 2006; 354(4): 387 - 396.