Jan Claassen

Detection of electrographic seizures with continuous EEG monitoring in critically ill patients

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.

Guidelines for the Evaluation and Management of Status Epilepticus

Status epilepticus (SE) treatment strategies vary substantially from one institution to another due to the lack of data to support one treatment over another. To provide guidance for the acute treatment of SE in critically ill patients, the Neurocritical Care Society organized a writing committee to evaluate the literature and develop an evidence-based and expert consensus practice guideline. Literature searches were conducted using PubMed and studies meeting the criteria established by the writing committee were evaluated. Recommendations were developed based on the literature using standardized assessment methods from the American Heart Association and Grading of Recommendations Assessment, Development, and Evaluation systems, as well as expert opinion when sufficient data were lacking.

Treatment of Refractory Status Epilepticus with Pentobarbital, Propofol, or Midazolam: A Systematic Review

Summary:  Background: New continuous infusion antiepileptic drugs (cIV‐AEDs) offer alternatives to pentobarbital for the treatment of refractory status epilepticus (RSE). However, no prospective randomized studies have evaluated the treatment of RSE. This systematic review compares the efficacy of midazolam (MDL), propofol (PRO), and pentobarbital (PTB) for terminating seizures and improving outcome in RSE patients.

Impact of medical complications on outcome after subarachnoid hemorrhage.

Objective:Medical complications occur frequently after subarachnoid hemorrhage (SAH). Their impact on outcome remains poorly defined. Design:Inception cohort study. Patients:Five-hundred eighty patients enrolled in the Columbia University SAH Outcomes Project between July 1996 and May 2002. Setting:Neurologic intensive care unit. Interventions:Patients were treated according to standard management protocols. Measurements and Main Results:Poor outcome was defined as death or severe disability (modified Rankin score, 4–6) at 3 months. We calculated the frequency of medical complications according to prespecified criteria and evaluated their impact on outcome, using forward stepwise multiple logistic regression after adjusting for known predictors of poor outcome. Thirty-eight% had a poor outcome; mortality was 21%. The most frequent complications were temperature >38.3°C (54%), followed by anemia treated with transfusion (36%), hyperglycemia >11.1 mmol/L (30%), treated hypertension (>160 mm Hg systolic; 27%), hypernatremia >150 mmol/L (22%), pneumonia (20%), hypotension (<90 mm Hg systolic) treated with vasopressors (18%), pulmonary edema (14%), and hyponatremia <130 mmol/L (14%). Fever (odds ratio [OR], 2.0; 95% confidence interval [CI], 1.1–3.4; p = .02), anemia (OR, 1.8; 95% CI, 1.1–2.9; p = .02), and hyperglycemia (OR, 1.8; 95% CI, 1.1–3.0; p = .02) significantly predicted poor outcome after adjustment for age, Hunt-Hess grade, aneurysm size, rebleeding, and cerebral infarction due to vasospasm. Conclusions:Fever, anemia, and hyperglycemia affect 30% to 54% of patients with SAH and are significantly associated with mortality and poor functional outcome. Critical care strategies directed at maintaining normothermia, normoglycemia, and prevention of anemia may improve outcome after SAH. LEARNING OBJECTIVESOn completion of this article, the reader should be able to: Identify common medical complications after subarachnoid hemorrhage. Describe complications that influence outcome. Use this inofrmation in a clinical setting. Dr. Connolly has disclosed that he is/was the recipient of direct grant/research funds from the National Institutes of Health. The remaining authors have disclosed that they have no financial relationships with or interests in any commercial companies pertaining to the educational activity. Wolters Kluwer has identified and resolved all faculty conflicts of interest regarding the educational activity. Visit the Critical Care Medicine Web site (www.ccmjournal.org) for information on obtaining continuing medical education credit.

Global Cerebral Edema After Subarachnoid Hemorrhage Frequency, Predictors, and Impact on Outcome

Background and Purpose— Cerebral edema visualized by CT is often seen after subarachnoid hemorrhage (SAH). Inflammatory or circulatory mechanisms have been postulated to explain this radiographic observation after SAH. We sought to determine the frequency, causes, and impact on outcome of early and delayed global cerebral edema after SAH. Methods— We evaluated the presence of global edema on admission and follow-up CT scans in 374 SAH patients admitted within 5 days of onset to our Neurological Intensive Care Unit between July 1996 and February 2001. Using multivariate analysis, we identified predictors of global cerebral edema and evaluated the impact of global edema on outcome 3 months after onset with the modified Rankin Scale. Results— Global edema was present on admission CT scans in 8% (n=29) and developed secondarily in 12% (n=44) of the patients. Global edema on admission was predicted by loss of consciousness at ictus and increasing Hunt-Hess grade. Delayed global edema was predicted by aneurysm size >10 mm, loss of consciousness at ictus, use of vasopressors, and increased SAH sum scores. Thirty-seven percent (n=137) of the patients were dead or severely disabled (modified Rankin Scale 4 to 6) at 3 months. Death or severe disability was predicted by any global edema, aneurysm size >10 mm, loss of consciousness at ictus, increased National Institutes of Health Stroke Scale scores, and older age. Conclusions— Global edema is an independent risk factor for mortality and poor outcome after SAH. Loss of consciousness, which may reflect ictal cerebral circulatory arrest, is a risk factor for admission global edema, and vasopressor-induced hypertension is associated with the development of delayed global edema. Critical care management strategies that minimize edema formation after SAH may improve outcome.

American Clinical Neurophysiology Society's Standardized Critical Care EEG Terminology: 2012 version.

Continuous EEG Monitoring is becoming a commonly used tool in assessing brain function in critically ill patients. However, there is no uniformly accepted nomenclature for EEG patterns frequently encountered in these patients such as periodic discharges, fluctuating rhythmic patterns, and combinatio

Prediction of symptomatic vasospasm after subarachnoid hemorrhage: the modified fisher scale.

OBJECTIVE We developed a modification of the Fisher computed tomographic rating scale and compared it with the original Fisher scale to determine which scale best predicts symptomatic vasospasm after subarachnoid hemorrhage. METHODS We analyzed data from 1355 subarachnoid hemorrhage patients in the placebo arm of four randomized, double-blind, placebo-controlled studies of tirilazad. Modified Fisher computed tomographic grades were calculated on the basis of the presence of cisternal blood and intraventricular hemorrhage. Crude odds ratios (OR) reflecting the risk of developing symptomatic vasospasm were calculated for each scale level, and adjusted ORs expressing the incremental risk were calculated after controlling for known predictors of vasospasm. RESULTS Of 1355 patients, 451 (33%) developed symptomatic vasospasm. For the modified Fisher scale, compared with Grade 0 to 1 patients, the crude OR for vasospasm was 1.6 (95% confidence interval [CI], 1.0-2.5) for Grade 2, 1.6 (95% CI, 1.1-2.2) for Grade 3, and 2.2 (95% CI, 1.6-3.1) for Grade 4. For the original Fisher scale, referenced to Grade 1, the OR for vasospasm was 1.3 (95% CI, 0.7-2.2) for Grade 2, 2.2 (95% CI, 1.4-3.5) for Grade 3, and 1.7 (95% CI, 1.0-3.0) for Grade 4. Early angiographic vasospasm, history of hypertension, neurological grade, and elevated admission mean arterial pressure were identified as risk factors for symptomatic vasospasm. After adjusting for these variables, the modified Fisher scale remained a significant predictor of vasospasm (adjusted OR, 1.28; 95% CI, 1.06-1.54), whereas the original Fisher scale was not. CONCLUSION The modified Fisher scale, which accounts for thick cisternal and ventricular blood, predicts symptomatic vasospasm after subarachnoid hemorrhage more accurately than original Fisher scale.

ELECTROGRAPHIC SEIZURES AND PERIODIC DISCHARGES AFTER INTRACEREBRAL HEMORRHAGE

Objective: To determine the frequency and significance of electrographic seizures and other EEG findings in patients with intracerebral hemorrhage (ICH). Methods: We reviewed 102 consecutive patients with ICH who underwent continuous electroencephalographic monitoring (cEEG). Demographic, clinical, radiographic, and cEEG findings were recorded. Using multivariate logistic regression analysis, we determined factors associated with 1) electrographic seizures, 2) periodic epileptiform discharges (PEDs), and 3) poor outcome (death, vegetative or minimally conscious state) at hospital discharge. Results: Seizures occurred in 31% (n = 32) of patients with ICH, prior to cEEG in 19 patients. Eighteen percent (n = 18) of patients had electrographic seizures; only one of these patients also had clinical seizures while on cEEG. After controlling for demographic and clinical predictors, only an increase in ICH volume of 30% or more between admission and 24-hour follow-up CT scan was associated with electrographic seizures (33% vs 15%; OR 9.5, 95% CI 1.7 to 53.8). PEDs were less frequently seen in those with hemorrhages located at least 1 mm from the cortex (8% vs 29%; OR 0.2, 95% CI 0.1 to 0.7). PEDs were independently associated with poor outcome (65% vs 17%; OR 7.6, 95% CI 2.1 to 27.3). In patients with electrographic seizures, the first seizure was detected within the first hour of cEEG monitoring in 56% and within 48 hours in 94%. Conclusions: Seizures occurred in one third of patients with intracerebral hemorrhage (ICH) and over half were purely electrographic. Electrographic seizures were associated with expanding hemorrhages, and periodic discharges with cortical ICH and poor outcome. Further research is needed to determine if treating or preventing seizures or PEDs might lead to improved outcome after ICH. GLOSSARY: BIPLEDs = bilateral independent PLEDs; cEEG = continuous EEG monitoring; CLUES = clinically unrecognized electrographic seizures; EVD = external ventricular drain; IRDA = frontal intermittent rhythmic delta activity; GCS = Glasgow Coma Score; GOS = Glasgow Outcome Scale; GPDs = generalized periodic discharges; ICH = intracerebral hemorrhage; ICP = intracranial pressure; ICU = intensive care unit; IVH = intraventricular hemorrhage; NICU = neuroICU; PEDs = periodic epileptiform discharges; PLEDs = periodic lateralized epileptiform discharges; SAH = subarachnoid hemorrhage; SDH = subdural hematomas; SE = status epilepticus; SIRPIDS = stimulus-induced rhythmic, periodic, or ictal discharges.

Continuous electroencephalography in the medical intensive care unit.

Objectives:To examine predictors and the prognostic value of electrographic seizures (ESZs) and periodic epileptiform discharges (PEDs) in medical intensive care unit (MICU) patients without a primary acute neurologic condition. Design:Retrospective study. Setting:MICU in a university hospital. Patients:A total of 201 consecutive patients admitted to the MICU between July 2004 and January 2007 without known acute neurologic injury and who underwent continuous electroencephalography monitoring (cEEG) for investigation of possible seizures or changes in mental status. Intervention:None. Measurements and Main Results:Median time from intensive care unit (ICU) admission to cEEG was 1 day (interquartile range 1–4). The majority of patients (60%) had sepsis as the primary admission diagnosis and 48% were comatose at the time of cEEG. Ten percent (n = 21) of patients had ESZs, 17% (n = 34) had PEDs, 5% (n = 10) had both, and 22% (n = 45) had either ESZs or PEDs. Seizures during cEEG were purely electrographic (no detectable clinical correlate) in the majority (67%) of patients. Patients with sepsis had a higher rate of ESZs or PEDs than those without sepsis (32% vs. 9%, p < 0.001). On multivariable analysis, sepsis at ICU admission was the only significant predictor of ESZs or PEDs (odds ratio 4.6, 95% confidence interval 1.9–12.7, p = 0.002). After controlling for age, coma, and organ dysfunction, the presence of ESZs or PEDs was associated with death or severe disability at hospital discharge (89% with ESZs or PEDs, vs. 39% if not; odds ratio 19.1, 95% confidence interval 6.3–74.6, p < 0.001). Conclusion:In this retrospective study of MICU patients monitored with cEEG, ESZs and PEDs were frequent, predominantly in patients with sepsis. Seizures were mainly nonconvulsive. Both seizures and periodic discharges were associated with poor outcome. Prospective studies are warranted to determine more precisely the frequency and clinical impact of nonconvulsive seizures and periodic discharges, particularly in septic patients.

Clinical trial of a novel surface cooling system for fever control in neurocritical care patients

Objective:To compare the efficacy of a novel water-circulating surface cooling system with conventional measures for treating fever in neuro-intensive care unit patients. Design:Prospective, unblinded, randomized controlled trial. Setting:Neurologic intensive care unit in an urban teaching hospital. Patients:Forty-seven patients, the majority of whom were mechanically ventilated and sedated, with fever ≥38.3°C for >2 consecutive hours after receiving 650 mg of acetaminophen. Interventions:Subjects were randomly assigned to 24 hrs of treatment with a conventional water-circulating cooling blanket placed over the patient (Cincinnati SubZero, Cincinnati OH) or the Arctic Sun Temperature Management System (Medivance, Louisville CO), which employs hydrogel-coated water-circulating energy transfer pads applied directly to the trunk and thighs. Measurements and Main Results:Diagnoses included subarachnoid hemorrhage (60%), cerebral infarction (23%), intracerebral hemorrhage (11%), and traumatic brain injury (4%). The groups were matched in terms of baseline variables, although mean temperature was slightly higher at baseline in the Arctic Sun group (38.8 vs. 38.3°C, p = .046). Compared with patients treated with the SubZero blanket (n = 24), Arctic Sun-treated patients (n = 23) experienced a 75% reduction in fever burden (median 4.1 vs. 16.1 C°-hrs, p = .001). Arctic Sun-treated patients also spent less percent time febrile (T ≥38.3°C, 8% vs. 42%, p < .001), spent more percent time normothermic (T ≤37.2°C, 59% vs. 3%, p < .001), and attained normothermia faster than the SubZero group median (2.4 vs. 8.9 hrs, p = .008). Shivering occurred more frequently in the Arctic Sun group (39% vs. 8%, p = .013). Conclusion:The Arctic Sun Temperature Management System is superior to conventional cooling-blanket therapy for controlling fever in critically ill neurologic patients.