Case report: Invasive neuromonitoring in status epilepticus induced hypoxic ischemic brain injury

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.

To determine whether nonconvulsive electrographic post-traumatic seizures result in increases in intracranial pressure and microdialysis lactate/pyruvate ratio. Prospective monitoring with retrospective data analysis. Single center academic neurologic intensive care unit. Twenty moderate to severe traumatic brain injury patients (Glasgow Coma Score 3-13). Continuous electroencephalography and cerebral microdialysis were performed for 7 days after injury. Ten patients had seizures and were compared with a matched cohort of traumatic brain injury patients without seizures. The seizures were repetitive and constituted status epilepticus in seven of ten patients. Using a within-subject design, post-traumatic seizures resulted in episodic increases in intracranial pressure (22.4 +/- 7 vs. 12.8 +/- 4.3 mm Hg; p < .001) and an episodic increase in lactate/pyruvate ratio (49.4 +/- 16 vs. 23.8 +/- 7.6; p < .001) in the seizure group. Using a between-subjects comparison, the seizure group demonstrated a higher mean intracranial pressure (17.6 +/- 6.5 vs. 12.2 +/- 4.2 mm Hg; p < .001), a higher mean lactate/pyruvate ratio (38.6 +/- 18 vs. 27 +/- 9; p < .001) compared with nonseizure patients. The intracranial pressure and lactate/pyruvate ratio remained elevated beyond postinjury hour 100 in the seizure group but not the nonseizure group (p < .02). Post-traumatic seizures result in episodic as well as long-lasting increases in intracranial pressure and microdialysis lactate/pyruvate ratio. These data suggest that post-traumatic seizures represent a therapeutic target for patients with traumatic brain injury.

To test ketamine infusion efficacy in the treatment of super-refractory status epilepticus (SRSE), we studied retrospectively SRSE patients who were treated with ketamine. Additionally, we studied the effect of high doses of ketamine on brain physiology as reflected by invasive multimodality monitoring (MMM). We studied a consecutive series of 68 SRSE patients who were admitted between 2009 and 2018, were treated with ketamine and monitored with scalp EEG. Eleven of these patients underwent MMM at the time of ketamine administration. We compared patients who had seizure cessation after ketamine initiation to those who did not. Mean age was 53+/-18 years old, 46% of patients were female. Seizure burden decreased by at least 50% within 24 hours of starting ketamine in 55 (81%) patients, with complete cessation in 43 (63%). Average dose of ketamine infusion was 2.2+/-1.8 mg/kg/h, with median duration of 2 (1; 4) days. Average dose of midazolam was 1.0+/-0.8 mg/kg/h at the time of ketamine initiation and was started at a median of 0.4 (0.1; 1.0) days before ketamine. Using a generalized linear mixed effect model, ketamine was associated with stable mean arterial pressure (OR 1.39, 95% CI 1.38-1.40), and with decreased in vasopressor requirements over time. We found no effect on intracranial pressure, cerebral blood flow, and cerebral perfusion pressure. Ketamine treatment was associated with a decrease in seizure burden in patients with SRSE. Our data support the notion that high dose ketamine infusions are associated with decreased vasopressor requirements without increased intracranial pressure. This study provides Class IV evidence that ketamine decreases seizures in patients with SRSE.