Thymatron
®
System IV Instructions for Use
41
Press and hold in the PERCENT ENERGY dial at any time to display the stimulus program in effect. Release the
dial to return to the PERCENT ENERGY display.
FREQUENCY SELECTION
When a factory-programmed preset stimulus is in effect, frequency is automatically adjusted for any given
PERCENT ENERGY setting. Selecting a specific frequency takes the Thymatron® System IV out of any preset
program. To select a specific stimulus frequency:
FLEXDIAL™ FREQUENC 10 to 70 Hz
PULSEWIDTH SELECTION
When a factory-programmed preset stimulus is in effect, the pulsewidth is automatically adjusted for any given
PERCENT ENERGY setting. Selecting a specific pulsewidth takes the Thymatron® System IV out of any preset
program. To select a specific stimulus pulsewidth:
FLEXDIAL™ P-WIDTH 0.25 (0.3) to 1.5 ms
Because stimulus duration is limited to a maximum of 8 seconds, the higher PERCENT ENERGY settings will
not be available when manually setting the 0.25 (0.3) ms pulsewidth, which will provide stimuli only up to the
50% ENERGY. However, when the LOW 0.25 (LOW 0.3) program is in effect, stimuli of up to 100% ENERGY
can be delivered because, for this program only, the frequency can go as high as 140 Hz.
STIMULUS DOSE FOR BILATERAL, BITEMPORAL, BIFRONTAL, LART ECT
For the initial treatment, select the LOW 0.5 program. The PERCENT ENERGY dial should be set to
approximately one-half the patient’s age (e.g., 25% for a 50 year-old). If no seizure activity results, the
PERCENT ENERGY setting should be increased to 100% and the patient re-stimulated within 30-60 seconds to
maximize the likelihood of obtaining a therapeutically satisfactory seizure at the first treatment session.
Before the next treatment day, the patient’s history and records should be reviewed to ensure that dehydration or
ingestion of sedative-hypnotic or anticonvulsant medications have not contributed to the difficulty in obtaining a
good seizure. Consideration should be given at the next treatment session to administering a stimulus dose at the
patient’s age or at maximum charge.
STIMULUS DOSE FOR UNILATERAL ECT
Satisfactory therapeutic results can be obtained with right unilateral ECT by simply setting the PERCENT
ENERGY dial to approximate the patient’s age in years (e.g., 75% for a 72 year-old patient). If a satisfactory
seizure is not obtained to the initial stimulus with right unilateral ECT, proceed as described in the paragraphs
