Indications, Technical Specifications and Clinical Practice of Continuous EEG Monitoring of Critically Ill Adults and Children

Critically ill patients face a high risk of neurological issues, including seizures, ischemia, edema, infections, and elevated intracranial pressure. These conditions can lead to permanent neurological disabilities if left untreated. Despite these dangers, methods for continuously monitoring brain function are scarce. Electroencephalography (EEG) measures electrical activity in the brain, can be recorded continuously at the bedside, offers good spatial resolution and excellent temporal precision, and is sensitive to changes in brain structure and function. Over the past decade, technological advancements have enhanced the efficiency of continuous EEG (CEEG) recording and remote analysis, resulting in a more than fourfold increase in CEEG use in intensive care units (ICUs). Recent surveys reveal significant variability in how and why CEEG is employed in ICUs, underscoring the need for clinical guidelines for this costly and labor-intensive procedure.

Critical care continuous EEG (CCEEG) involves simultaneous recording of EEG and clinical behavior over extended periods, typically hours to weeks, in critically ill patients at risk of neurological deterioration. CCEEG often includes video recording and graphical displays of quantitative EEG trends. Its goal is to detect changes in brain function, such as nonconvulsive seizures or ischemia, that might not be apparent through neurological examination alone, facilitating early detection and management of these abnormalities. This consensus statement applies to critically ill adult and pediatric patients but not to long-term monitoring of awake patients with epilepsy, sleep monitoring, or intraoperative EEG. Recommendations for CEEG in critically ill neonates are separate.

CCEEG is a rapidly evolving technology, and this statement focuses on current consensus-based guidelines. While there is insufficient data on CCEEG's impact on clinical outcomes to establish evidence-based practice standards, existing evidence is summarized below. Given that nonconvulsive seizures and other secondary brain injuries often go unrecognized without CCEEG, this document emphasizes that delayed recognition is better than none.

Typically, CCEEG is recorded continuously but reviewed intermittently by neurodiagnostic technologists (NDTs) for technical quality and changes in EEG patterns, and by electroencephalographers for interpretation and clinical correlation. The decision to initiate CCEEG, review frequency, and communicate results to ICU caregivers depends on local resources, monitoring indications, and the patient's clinical status. CCEEG indications and technical specifications will be updated as new data emerge.

The American Clinical Neurophysiology Society's CCEEG Guidelines Committee outlines various models for CCEEG. Some techniques are available only in specialized centers, representing an idealized system. The committee acknowledges that many CCEEG programs lack access to all necessary equipment, technical staff, and interpreters but should use these guidelines for program development and improvement. Each center should provide CCEEG at the highest level possible with local resources and consider transferring patients to more specialized centers if local resources are insufficient.

CCEEG is often requested urgently in critically ill patients. Current staffing models may not support 24-hour, 7-day-a-week in-house NDT coverage. This consensus statement therefore addresses minimum techniques for CCEEG under emergency conditions and optimal techniques once qualified NDTs are available.

The required duration of CCEEG varies based on monitoring indications and patient characteristics. In most cases, a minimum of 24 hours of recording is recommended, with longer recording advised for selected populations (see Section II. Indications). To optimally detect neurological deterioration, CCEEG should be initiated as soon as possible in patients with acute brain injuries, altered mental status, or risk of brain ischemia (see Section II. Indications). Subsequent CCEEG recordings can be compared to this initial baseline to identify secondary neurological insults.

The second section of this consensus statement outlines the most common indications for CCEEG in adults and children. Subsequent sections cover technical aspects, including personnel qualifications, equipment, documentation, and safety. The final sections address commonly used techniques for specific indications in both adults and children.