More ICU Patients Survive when cEEG is used versus routine EEG

(39% - 25% In-hospital mortality)

Continuous and routine EEG in intensive care: Utilization and outcomes, United States 2005-2009

Ney, JP, et.al., Neurology. 2013 Dec 3;81(23):2002-8

This was a retrospective study of 8 million inpatient records of which 40,945 met the criteria representing 20% of all inpatient discharges in non-federal US hospitals. Adult ICU discharge records reporting mechanical ventilation and EEG (routine EEG or cEEG) were included. cEEG was compared with routine EEG alone in association with the primary outcome of in-hospital mortality and secondary outcomes of total hospital charges and length of stay.

CONCLUSIONS:

cEEG is favorably associated with inpatient survival (25% inpatient mortality vs 39% for routine EEG only) in mechanically ventilated patients, without adding significant charges to the hospital stay.

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Dr. Ney (11/22/2013) comments:

Myself and my colleagues used a large, nationally representative dataset with information pooled over a period of five years to look at the effects of different forms of electroencephalography (EEG, a form of brainwave testing) on mortality, costs, and length of stay in the intensive care unit (ICU).

We compared ICU patients who received routine 20-40 minute portable EEGs with those who received 24 hour continuous EEG monitoring (cEEG). A priori, we assumed that patients who received the more intensive treatment(continuous EEG) would likely be sicker and have worse outcomes. To our surprise, this was not the case. Rather, these patients were less likely to die in the hospital than the patients who received routine EEGs only (25% inpatient mortality for cEEG vs. 39% for routine EEG). This finding was highly statistically significant and robust to adjustment for demographic, clinical, and hospital-related factors. Furthermore, there was no significant difference to cost or length of stay after adjustment.

We also found that use of ICU-cEEG grew by 263% over the five year study period relative to generally flat growth for routine EEG in the ICU. The reason for a mortality benefit to ICU-cEEG monitoring may relate to faster reaction to ongoing brain injury, particularly seizures, where abnormalities on continuous EEG may be quickly detected then acted upon to prevent conditions associated with higher mortality, such as non-convulsive status epilepticus. The effect did not appear related to being in academic medical centers, or having a primary neurological diagnosis as would be more likely in an intensive care unit designed specifically for taking care of neurological conditions and injuries (Neuro-ICU).

There were a number of limitations to the study. We looked only at patients who received some kind of EEG, which was less than one percent of the ICU patient as a whole. We only looked at adults in the intensive care unit. There may be other selection bias for continuous EEG monitoring that we were not able to control for given the limits of the data. Still, these findings are highly encouraging for the usage of an emerging technology in the management of some of our sickest patients. Certainly, future research should focus on validating these findings, especially in a general ICU population using prospectively collected data, ultimately to gauge efficacy in a randomized, controlled trial. In the meantime, intensive care clinicians should consider continuous EEG monitoring when they feel that electroencephalography is warranted.