Pulse Oximetry
50
Marquette Responder® 3000
227 490 02-C
C-Lock ECG Synchronization
The C-Lock ECG synchronization feature enables
the device to use an ECG signal as a reference
point for identifying the pulse and synchronizing
saturation measurements. This enhances the
measurement accuracy when the patient's
perfusion is poor and in the presence of patient
movement.
When an ECG signal is present during SpO
2
measurement, the device receives two separate
signals that reflect cardiac activity; an opti-
cal/electrical signal from the SpO
2
probe and the
ECG signal. The time that elapses between the
ECG R-wave and the optical pulse detected at the
probe site depends on the heart rate and on the
location of the probe. However, for a given patient
the length of the delay is relatively stable, and the
device uses that time relationship to identify good
pulses and reject non-synchronized artifacts.
Application Tips
General Tips
−
Use only the probes listed in chapter 20 "Order
Information". Apply the probes as described in
their instructions for use. Carefully observe all
information and cautions given in these in-
structions.
−
Take care that the probe does not exert too
much pressure when applied to avoid erroneous
readings and blistering. Inadequate oxygen
supply to the skin, not heat, causes blisters.
−
Change the probe site at least every 24 hours to
allow the skin to breathe.
−
Be careful to ensure continued circulation at
the probe site.
−
Incident light may cause inaccurate readings.
Cover the measuring site with a cloth, if neces-
sary.
−
It may not be possible to measure SpO
2
values,
if cardiac output is determined at the same time
by means of the dye dilution technique.
−
It may not be possible to measure SpO
2
values
or the pulse rate, if the circulation is impaired
(e.g. by a blood-pressure cuff or by an ex-
tremely high vascular resistance).
−
Remove nail varnish and artificial finger nails
before applying the probe. Both may lead to
inaccurate readings.
−
Do not apply the finger probe to the same arm
as the blood-pressure cuff.
