The overall goal of this clinical examination technique is to monitor infant's cerebral function status during treatment in the neonatal intensive care unit. This method can help to evaluate the cerebral function status and brain maturation in term and preterm infants. The main advantage of this bedside technique is that it is easily accessible and can be used on any infant in the neonatal intensive care unit.
Demonstrating the procedure will be Susanne, a nurse from our own EQ.Begin by connecting the aEEG device to electrical power at the location where the monitoring will take place. Next, collect two electrodes for a single-channel amplitude integrated EEG, or aEEG, and four electrodes for a two-channel aEEG. If not using needle electrodes, choose the type of electrodes you want to use instead.
Prepare a positioning strip, skin disinfectant, tape appropriate for use in neonates, swabs, skin preparation gel, a module box, and contact gel for gold cups. Plug the module box into the aEEG device. Apply the electrodes during routine care by first disinfecting the skin.
Then place skin preparation gel on a cotton swab until it is moist. Apply a few gentle strokes with the cotton swab using very little pressure. Then place the reference electrode on the back or the chest of the infant.
After the reference electrode has been placed, put the measuring device on the infant's head and line up the same signs on the infant's tragus and sagittal suture. Then right before placing the remaining electrodes on the infant's head, disinfect the area indicated by the arrows on the measuring device. When using needle electrodes, stretch the skin slightly and insert the needle tangentially, just underneath the skin of the markings with the tip of the needle pointing in the caudal direction.
Use tape to keep the electrode in place. Next, insert the cables into the module box as indicated by the legend on the box. If the impedance of the reference electrode, gold cups, or hydrogel electrodes is not satisfactory, perform a few strokes with the cotton swab under the corresponding electrode.
Finally, start the recording. If using gold cups, fill each cup with contact gel. Place the cup in the proper position with the cable running towards the head end, tape it into place.
Alternatively, if using hydrogel electrodes, place the electrodes with the cable running towards the head end. Ensure that all electrodes are in place and there is no mechanical contact between electrodes. If required, place a CPAP hat or headband on top of the aEEG electrodes.
During the recording, regularly check for impedance and the dislocation of electrodes to obtain quality recordings. Mark events to facilitate the identification of artefacts using the provided button on the screen of the cerebral function monitor. Check the infant for skin irritation to avoid lesions or infections.
Leave aEEG electrodes in place for intubation, or other invasive measures to resume the recording later. In case the cables are not long enough to move the infant within the incubator, disconnect them from the module box, and reconnect them after the procedure. Finally, review the tracing at the end of the recording on the monitor, or transfer it to an external storage device.
During an aEEG, continuous and discontinuous normal voltage patterns are considered physiological background patterns in term and preterm infants, respectively. A burst suppression pattern, continuous low-voltage pattern, and a flat trace, are pathological background patterns. Seizures in term infants have a characteristic shape with a sudden rise of both the lower and upper border.
In preterm infants however, seizures can be camouflaged by the discontinuous background pattern, and may only be detected by viewing the raw EEG. Once mastered, this technique can be done in a few minutes if it's performed properly. During the recording it's important to check for impedance and electrode dislocation regularly.
After watching this video you should have a good understanding of how to plan an aEEG monitor to a neonate and how to make sure you receive a good quality recording.
