Now that techs are returning to the lab and performing more EEGs, some are voicing concern over performing one specific activation procedure: hyperventilation (HV). This commonly used technique’s potential for spreading the novel coronavirus is driving their worries.
According to ASET- the Diagnostic Society, activation procedures are commonly used during EEG testing as a way to “induce, enhance, or better define abnormal EEG patterns.” These activators include sleep, photic stimulation, and hyperventilation. Hyperventilation, also called overbreathing, is usually performed at a rate of 18 to 24 breaths per minute for 3 to 5 minutes.
“Hyperventilation is a standard part of all routine EEGs for patients who are developmentally able to participate and do not have a contraindication (such as Moya Moya),” says Dr. Sophia French, a child neurologist at Oregon Health and Science University in Portland, Oregon. “It is most valuable in patients with concern for generalized epilepsies, such as Childhood Absence Epilepsy, as hyperventilation can induce epileptiform discharges and even seizures that might otherwise be missed. Hyperventilation can also bring out intermittent focal slowing.”
Though useful, hyperventilation can also force particles from inside the airways out into the surroundings. If this discharge contains a pathogen, it may potentially infect others. For this reason, the American Clinical Neurophysiology Society (ACNS) says that activation procedures, especially hyperventilation, should not be performed on a COVID-19-positive patient or a patient under investigation.
“In patients with low concern for COVID, rather than routinely performing hyperventilation and photic stimulation on all patients, patients should be selected for high diagnostic yield,” ACNS adds.
This means that the decision to do hyperventilation needs to be carefully weighed against risk.
“HV is a very important activation procedure, especially in pediatrics, so the technologist or manager should work closely with the interpreting physician to determine medical necessity,” says Anna Bonner, a neurodiagnostic technologist and co-author of ASET’s latest (pre-COVID) infection control guidelines.
HV should be done using COVID-19 precautions (even if testing is negative), if it’s considered important enough to perform. During a recent town hall hosted by ASET, several panelists mentioned that their institutions have begun allowing HV when necessary – but require techs to wear N95 masks and sometimes goggles.
“At our institution, providers and EEG technicians wear masks for all patient encounters in the setting of the COVID-19 pandemic,” adds French.
Bonner further recommends that techs should maintain safe distancing and wear appropriate PPE, including a mask, goggles and face shield, in cases where HV is ordered to be performed.
“And if a pinwheel is used or any assisting device, it should be disposable,” she adds. “Extra care/cleaning of surrounding surfaces should be taken, following the CDC’s guidelines for surface cleaning in the time of COVID.”
Special thanks to Anna M. Bonner, BA, R. EEG T., RPSGT, Director of Publications at ASET-The Neurodiagnostic Society, and Sophia French, MD., who recently completed her residency in child neurology at Oregon Health and Science University in Portland, Oregon.