Safety profile of an intracranial multimodal monitoring bolt system for neurocritical care: a single-center experience

Comparison of Continuous Intracortical and Scalp Electroencephalography in Comatose Patients with Acute Brain Injury

BACKGROUND

Depth electroencephalography (dEEG) is a recent invasive monitoring technique used in patients with acute brain injury. This study aimed to describe in detail the clinical manifestations of nonconvulsive seizures (NCSzs) with and without a surface EEG correlate, analyze their long-standing effects, and provide data that contribute to understanding the significance of certain scalp EEG patterns observed in critically ill patients.

METHODS

We prospectively enrolled a cohort of 33 adults with severe acute brain injury admitted to the neurological intensive care unit. All of them underwent multimodal invasive monitoring, including dEEG. All patients were scanned on a 3T magnetic resonance imaging scanner at 6 months after hospital discharge, and mesial temporal atrophy (MTA) was calculated using a visual scale.

RESULTS

In 21 (65.6%) of 32 study participants, highly epileptiform intracortical patterns were observed. A total of 11 (34.3%) patients had electrographic or electroclinical seizures in the dEEG, of whom 8 had both spontaneous and stimulus-induced (SI) seizures, and 3 patients had only spontaneous intracortical seizures. An unequivocal ictal scalp correlate was observed in only 3 (27.2%) of the 11 study participants. SI-NCSzs occurred during nursing care, medical procedures, and family visits. Subtle clinical manifestations, such as restlessness, purposeless stereotyped movements of the upper limbs, ventilation disturbances, jerks, head movements, hyperextension posturing, chewing, and oroalimentary automatisms, occurred during intracortical electroclinical seizures. MTA was detected in 18 (81.8%) of the 22 patients. There were no statistically significant differences between patients with MTA with and without seizures or status epilepticus.

CONCLUSIONS

Most NCSzs in critically ill comatose patients remain undetectable on scalp EEG. SI-NCSzs frequently occur during nursing care, medical procedures, and family visits. Semiology of NCSzs included ictal minor signs and subtle symptoms, such as breathing pattern changes manifested as patient-ventilator dyssynchrony.

Complications of Intracranial Multimodal Monitoring for Neurocritical Care: A Systematic Review and Meta-Analysis

Intracranial multimodal monitoring (iMMM) is increasingly used for neurocritical care. However, concerns arise regarding iMMM invasiveness considering limited evidence in its clinical significance and safety profile. We conducted a synthesis of evidence regarding complications associated with iMMM to delineate its safety profile. We performed a systematic review and meta-analysis (PROSPERO Registration Number: CRD42021225951) according to the Preferred Reporting Items for Systematic Review and Meta-Analysis and Peer Review of Electronic Search Strategies guidelines to retrieve evidence from studies reporting iMMM use in humans that mention related complications. We assessed risk of bias using the Newcastle-Ottawa Scale and funnel plots. The primary outcomes were iMMM complications. The secondary outcomes were putative risk factors. Of the 366 screened articles, 60 met the initial criteria and were further assessed by full-text reading. We included 22 studies involving 1206 patients and 1434 iMMM placements. Most investigators used a bolt system (85.9%) and a three-lumen device (68.8%), mainly inserting iMMM into the most injured hemisphere (77.9%). A total of 54 postoperative intracranial hemorrhages (pooled rate of 4%; 95% confidence interval [CI] 0-10%; I2 86%, p < 0.01 [random-effects model]) was reported, along with 46 misplacements (pooled rate of 6%; 95% CI 1-12%; I2 78%, p < 0.01) and 16 central nervous system infections (pooled rate of 0.43%; 95% CI 0-2%; I2 64%, p < 0.01). We found 6 system breakings, 18 intracranial bone fragments, and 5 cases of pneumocephalus. Currently, iMMM systems present a similar safety profile as intracranial devices commonly used in neurocritical care. Long-term outcomes of prospective studies will complete the benefit-risk assessment of iMMM in neurocritical care. Consensus-based reporting guidelines on iMMM use are needed to bolster future collaborative efforts.

Combined depth and scalp electroencephalographic monitoring in acute brain injury: Yield and prognostic value

BACKGROUND AND PURPOSE

Depth electroencephalography (dEEG) is an emerging neuromonitoring technology in acute brain injury (ABI). We aimed to explore the concordances between electrophysiological activities on dEEG and on scalp EEG (scEEG) in ABI patients.

METHODS

Consecutive ABI patients who received dEEG monitoring between 2018 and 2022 were included. Background, sporadic epileptiform discharges, rhythmic and periodic patterns (RPPs), electrographic seizures, brief potentially ictal rhythmic discharges, ictal-interictal continuum (IIC) patterns, and hourly RPP burden on dEEG and scEEG were compared.

RESULTS

Sixty-one ABI patients with a median dEEG monitoring duration of 114 h were included. dEEG significantly showed less continuous background (75% vs. 90%, p = 0.03), higher background amplitude (p < 0.001), more frequent rhythmic spike-and-waves (16% vs. 3%, p = 0.03), more IIC patterns (39% vs. 21%, p = 0.03), and greater hourly RPP burden (2430 vs. 1090 s/h, p = 0.01), when compared to scEEG. Among five patients with seizures on scEEG, one patient had concomitant seizures on dEEG, one had periodic discharges (not concomitant) on dEEG, and three had no RPPs on dEEG. Features and temporal occurrence of electrophysiological activities observed on dEEG and scEEG are not strongly associated. Patients with seizures and IIC patterns on dEEG seemed to have a higher rate of poor outcomes at discharge than patients without these patterns on dEEG (42% vs. 25%, p = 0.37).

CONCLUSIONS

dEEG can detect abnormal electrophysiological activities that may not be seen on scEEG and can be used as a complement in the neuromonitoring of ABI patients.