Reusable EEG Electrodes May Put Patients at Risk of Infection

Reusable electroencephalographic (EEG) electrodes are under investigation as a potential source of hospital-acquired infection (HAI). Because the traditional EEG procedure involves abrasion of the skin, EEG electrodes are considered semi-critical devices, which require sterilization or high-level disinfection. Inadequately cleaned reusable cup electrodes may harbor bacteria, blood, and microscopic epithelial cells. Indeed, a break in the skin that occurs when applying EEG scalp electrodes creates the risk of infection from blood-borne pathogens such as HIV, Hepatitis-C, and Creutzfeldt-Jacob Disease.

The largest outbreak of Hepatitis B in history was due to reusable EEG electrodes

The risk of infection from EEG electrodes is not just theoretical. The largest outbreak of hepatitis B (HBV) in history was traced to an outpatient EEG lab that used subdermal and gold disk electrodes were used. Epidemiological evidence revealed an astounding 14,000 cases of HBV tied to the EEG lab between 1991 to 1996, including one HBV-related death.¹ Furthermore, Sohrt et al. published a retrospective study in 2018 reporting an incidence of 33 cases of sepsis per 100,000 EEG procedures using reusable cup electrodes.²

Lax disinfection persists despite risks

Unfortunately, many institutions lack standardized policies for cleaning. When they do have formalized protocols in place, it is not clear that the policies are strictly followed. Cleaning EEG electrodes is not always straightforward; it may be difficult to remove microscopic debris, such as blood. Moreover, cup electrodes and lead wires often become tangled, which complicates the cleaning process. ASET, the Neurodiagnostic Society, stipulates that electrodes may be cleaned with bleach or commercial chemical disinfectants.¹ However, these agents are often over-diluted, and are stored beyond the recommended shelf-life in the diluted state.

Reusable EEG electrodes poses a risk to institutions

Medical centers and clinics that use reusable EEG electrodes invite a considerable degree of scrutiny and assume a substantial risk for non-compliance. The Occupational Safety and Health Administration (OSHA) possesses the authority to inspect health care facilities that use medical devices, including semi-critical devices. OSHA may cite violations and assign fines for non-compliance with regulations such as the Bloodborne Pathogen Standard (29 CFR 1910.1030). Fines range from $250.00 to $70,000.00 per single violation. Thus, institutions that use reusable EEG electrodes and fail to clean the devices properly between patients are at risk of substantial fines and penalties. The reputational cost of an OSHA violation for unclean EEG electrodes is considerably higher.

Standard cleaning may not be enough to eliminate the risk of infection

Even after cleaning, reusable EEG electrodes may carry a risk of infection. In a recent prospective multicenter study by Albert et al. in the American Journal of Infection Control, investigators collected swabs from EEG cups and the lower third of electrode lead wires in 4 different epilepsy monitoring units. All electrodes had been disinfected with a 2-step process, which involved cleaning cup electrodes with a reusable brush and then soaking and washing with a germicidal bleach cleaner (1 site), presoaking-plus-cleaner (1 site), or using water and a dishwashing detergent (2 sites). This was followed by disinfection using a bleach-based spray, wipe, or liquid. The investigators found that, of 124 electrodes swabbed, 31 (25%) had a positive bacterial culture, 30 for a single bacterial species and one for two species.³ 88% of these bacterial species were classified as at potential risk or at risk of causing infection, and the cultured bacteria were drug-resistant in some cases.

Disposable EEG electrodes provide an elegant and cost-effective solution

These results suggest the use of reusable EEG electrodes poses a non-trivial risk to patients and that efforts to properly disinfect these electrodes face real practical barriers. Consequently, many clinical neurophysiology labs have switched to single-use EEG cup electrodes in response. Sorht et al. concluded in their cost-effectiveness analysis comparing single-use to reusable EEG cup electrodes that  single use electrodes reduced the risk of cross-contamination and may be more effective in avoiding sepsis.² In their base-case analysis, single use electrodes were associated with a small but significant cost-savings weighed against patient risk. Given their favorable safety, lower risk and cost profiles, the field will almost certainly continue to adopt single-use EEG electrode products.