Neuromonitoring in the ICU

Continuous Electroencephalographic Training for Neuroscience Intensive Care Unit Nurses: A Feasibility Study

BACKGROUND

Use of continuous electroencephalographic (cEEG) monitoring has more than doubled at our institution for the last 4 years. Although intensive care unit cEEG is reviewed remotely by board-certified epileptologists every 4 to 6 hours, there are inherent delays between occurrence, recognition, and treatment of epileptiform activity. Neuroscience intensive care unit (NSICU) nurses are uniquely positioned to monitor cEEG in real time yet do not receive formal training. The purpose of this study was to evaluate the effectiveness of an education program to teach nurses to monitor cEEG, identify a burst suppression pattern, and measure the duration of suppression.

METHODS

We performed a retrospective analysis of pretest and posttest data. All NSICU nurses (40) were invited to complete the pretest (PT-0), with 25 participating. Learning style/preference, demographics, comfort with cEEG, and knowledge of EEG fundamentals were assessed. A convenience cohort of NSICU nurses (13) were selected to undergo EEG training. Posttests evaluating EEG fundamental knowledge were completed immediately after training (PT-1), at 3 months (PT-3), and at 6 months (PT-6). The cohort also completed a burst suppression module after the training, which assessed ability to quantify the duration of suppression.

RESULTS

Mean cohort test scores significantly improved after the training (P < .001). All nurses showed improvement in test scores, and 76.9% passed PT-1 (a score of 80% or higher). Reported mean comfort level with EEG also significantly improved after the training (P = .001). There was no significant difference between mean cohort scores between PT-1, PT-3, and PT-6 (all 88.6%; P = 1.000). Mean cohort score from the bust suppression module was 73%, with test scores ranging from 31% to 93%.

CONCLUSIONS

NSICU nurses can be taught fundamentals of cEEG, to identify a burst suppression pattern, and to quantify the duration of suppression. Further research is needed to determine whether this knowledge can be translated into clinical competency and affect patient care.

Effect of sedation on quantitative electroencephalography after cardiac arrest

BACKGROUND

Electroencephalography (EEG) has clinical and prognostic importance after cardiac arrest (CA). Recently, interest in quantitative EEG (qEEG) analysis has grown. The qualitative effects of sedation on EEG are well known, but potentially confounding effects of sedatives on qEEG after anoxic injury are poorly characterized. We hypothesize that sedation increases suppression ratio (SR) and decreases alpha/delta ratio (ADR) and amplitude-integrated EEG (aEEG), and that the magnitude of sedation effects will be associated with outcome.

METHODS

We routinely monitor comatose post-arrest patients with EEG for 48-72h. We included comatose EEG-monitored patients after CA who had protocolized daily sedation interruptions. We used Persyst v12 to quantify qEEG parameters and calculated medians for 10min immediately prior to sedation interruption and for the last 5min of interruption. We used paired t-tests to determine whether qEEG parameters changed with sedation cessation, and logistic regression to determine whether these changes predicted functional recovery or survival at discharge.

RESULTS

78 subjects were included (median age 56, 65% male). Interruptions occurred a median duration of 34h post-arrest and lasted a median duration of 60min. Prior to interruption, higher aEEG predicted survival, while lower SR predicted both survival and favorable outcome. During interruption, SR decreased (p<0.001), aEEG increased (p=0.002), and ADR did not change. Larger decreases in SR predicted decreased survival (OR=1.04 per percent change; 95% CI 1.00-1.09).

CONCLUSION

Higher aEEG and lower SR predict survival after CA. Sedation alters aEEG and SR, but importantly does not appear to affect the relationship between these parameter values and outcome.