SPECT-negative SIRPIDs: Less aggressive neurointensive care?

INTRODUCTION:: The management of EEG patterns in comatose intensive care unit patients remains poorly studied regarding whether aggressive management improves outcomes. We hypothesized that stimulus-induced rhythmic, periodic, or ictal discharges (SIRPIDs) could be classified as ictal and interictal using single-photon emission computerized tomographic (SPECT) imaging to help guide aggressive or deescalate anticonvulsant management. METHODS:: We performed a retrospective review of all cases of ICU patients at a single center, tertiary care academic center for evidence of SIRPIDs with concomitant SPECT imaging over a one year period. RESULTS:: From 2011 to 2012, we retrospectively identified 2 of 235 intensive care unit EEGs-completed patients (both 20 minutes and continuous EEG), who had SIRPIDs who subsequently underwent SPECT imaging. Both patients were female, one aged 63 years who had aneurysmal subarachnoid hemorrhage and large intraparenchymal hematoma and the other aged 67 years who sustained a cardiac arrest. Continuous EEG in both demonstrated stimulation-provoked SIRPIDs within 6 to 8 days of hospitalization. A SPECT scan using technetium-hexamethylporpyleneamineoxime (HMPAO) performed during stimulation induced SIRPIDs on EEG, followed by a SPECT scan without SIRPIDs on EEG. In both patients, regional cerebral hyperperfusion was not present between the two SPECT scans. The absence of hyperperfusion on either scan and subtracted SPECT imaging helped reduce aggressive anticonvulsant use, infusion of propofol, or additional antiepileptic drugs. CONCLUSIONS:: Single-photon emission computerized tomographic scan-negative SIRPIDs may supplement the EEG and modify aggressive therapies, but larger outcome-based studies are needed.