User's Manual

Ultraview Care Network
24-6
The EEG is commonly divided into four frequency bands. From lowest to highest,
they are: Delta (less than 4 Hz), Theta (4 to 8 Hz), Alpha (8 to 13 Hz), and Beta
(13 Hz and higher). Delta waves emanate from the central region of the brain, and
occur most frequently if a patient is an infant or a sleeping adult. Theta waves,
also from the central region, occur in children and lightly sleeping adults. Alpha
waves originate primarily from the occipital region of the brain, and occur in adults
that are relaxed or drowsy. Finally, Beta waves emanate from the parietal and
frontal regions of the brain, and indicate that the patient is alert and awake.
Normal EEG patterns are influenced by cerebral blood flow, medications, and
anesthetic levels.
The beta band can be divided into two bands. The low beta band is labeled beta1
and usually represents signals between about 13 Hz and 20 Hz. The high beta
band is labeled beta2 and usually represents signals between about 20 Hz and 30
Hz. It is clinically useful to separate the beta band for trending purposes,
especially when looking at high frequency activity.
Setting Up the EEG Module
Up to six setup configurations can be saved and recalled as needed. To recall a
particular EEG display setup requires only that you touch one of the six recall
setup keys.
After determining what your EEG monitoring needs are, Spacelabs Medical
recommends that you pre-configure the EEG module and store your configuration
setup. Module configurations should be set up and stored prior to connecting a
patient for monitoring. In this way, you can simply select a pre-configured setup
after you connect the patient.
Also, some of the configuration menus are not available after EEG processing has
started. Therefore, it is recommended that you pre-configure the module, defining
the trend parameters, frequency ranges, and other variables (such as those
outlined in the bulleted list below), before processing starts. This way, you will not
have to stop processing to change some parameters.
The following sections describe:
• How to change the module’s EEG monitoring parameters and store them
• The EEG displays
• How to prepare the patient for monitoring
• How to connect the patient to the module
• Bedside and central monitors
CAUTION:
• The Spacelabs Medical model 90481 EEG module should
only be used by someone with a knowledge of and/or
background in EEG monitoring.