Fukuda Denshi LX-8000 Series, Operation Manual

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9. Other Setting Items
46
■ Time Constant
The default setting of the time constant is “0.4 second”.
If a stable monitoring is difficult with excessive change in the baseline due to
excessive body motion of the patient or an interference noise, such as AC
frequency, by changing the time constant to “0.1 second”, the monitoring may
become relatively stable.
For details of the setting, contact your local Fukuda Denshi service
representative.
CAUTION
 The threshold level for HR detection of this equipment and the receiving
monitor changes with ECG waveform size. Set a proper waveform size
for monitoring.
 When changing the time constant to “0.1 second”, the lower frequency
characteristic becomes 1.6 Hz ± 25%. This setup does not meet IEC
60601-2-27 standard. It may lead to a change in the ECG waveform and
the ST measurement value may be especially affected. Fukuda Denshi
recommends “0.4 seconds” setting in normal use.
 The display screen in normal use does not indicate the selection of time
constant. Make sure to take measures, such as marking on the
LX-8300M, to distinguish whether the selection of time constant has
changed.
■ Detection Sensitivity of the Pacemaker Pulse
The default setting of pacemaker pulse detection sensitivity is “Mid”.
The “Mid” setting can detect and reject the following pacemaker pulse
specified in IEC 60601-2-27 standard.
Detection/Rejection of Pacemaker Pulse:
a) Pacemaker Pulse without Over/Undershoot:
Capable to detect pulses of pulse width 0.1 ms to 2 ms,
amplitude ±2 mV to ±700 mV.
b) Pacemaker Pulse with Over/Undershoot:
Rejection is not possible.
Fukuda Denshi recommends the “Mid” setting in normal use.
There may be some cases when the pacemaker pulse cannot be detected
depending on the pacemaker type, pulse voltage, pulse width, electrode lead
type (unipolar, bipolar). In this case, change the lead or the position of the
electrodes to be able to detect the pacemaker pulse.
Nonetheless, if the detection is still undetectable, change the setting to “High”
in order to increase the detection sensitivity. So that smaller pacemaker pulse
can be detected. However, the “High” setting may lead to erroneous detection
due to interference noise, such as AC frequency.