Published in:
01-12-2012 | Original Article
Frequency of Non-convulsive Seizures and Non-convulsive Status Epilepticus in Subarachnoid Hemorrhage Patients in Need of Controlled Ventilation and Sedation
Published in: Neurocritical Care | Issue 3/2012
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Background
Non-convulsive seizures (NCSZ) can be more prevalent than previously recognized among comatose neuro-intensive care patients. The aim of this study was to evaluate the frequency of NCSZ and non-convulsive status epilepticus (NCSE) in sedated and ventilated subarachnoid hemorrhage (SAH) patients.
Methods
Retrospective study at a university hospital neuro-intensive care unit, from January 2008 until June 2010. Patients were treated according to a local protocol, and were initially sedated with midazolam or propofol or combinations of these sedative agents. Thiopental was added for treatment of intracranial hypertension. No wake-up tests were performed. Using NicoletOne® equipment (VIASYS Healthcare Inc., USA), continuous EEG recordings based on four electrodes and a reference electrode was inspected at full length both in a two electrode bipolar and a four-channel referential montage.
Results
Approximately 5,500 h of continuous EEG were registered in 28 SAH patients (33 % of the patients eligible for inclusion). The median Glasgow Coma scale was 8 (range 3–14) and the median Hunt and Hess score was 4 (range 1–4). During EEG registration, no clinical seizures were observed. In none of the patients inter ictal epileptiform activity was seen. EEG seizures were recorded only in 2/28 (7 %) patients. One of the patients experienced 4 min of an NCSZ and one had a 5 h episode of an NCSE.
Conclusion
Continuous EEG monitoring is important in detecting NCSZ in sedated patients. Continuous sedation, without wake-up tests, was associated with a low frequency of subclinical seizures in SAH patients in need of controlled ventilation.