Ecg Signal Processing And Display; Patient Preparation For Ecg Monitoring - Dräger Infinity M300 series Supplemental Manual

ECG signal processing and display

The M300/M300+ calculates heart rates within a range of 15 beats to 300 beats per minute, using the R-
R intervals of the last 10 seconds. This calculation excludes the two longest and two shortest R-R
intervals. The M300/M300+ averages the remaining intervals and displays the result as the current heart
rate in the heart rate parameter box.
During dual-channel processing, a weight is assigned to each channel depending on its level of artifact.
The channel with less artifact always receives the greater weight. When a channel exceeds a certain level
of artifact, it is excluded from the composite signal, and the M300/M300+ shifts to single-channel
processing. If both channels experience excessive artifact, the message ECG artifact appears until at
least one channel is sufficiently free of artifact.
During artifact, asterisks (* * *) replace the heart rate value. When the artifact clears, QRS processing
resumes without initiating a relearning phase.
NOTE
For heart rates of 300 bpm and greater, the mon-
itor may display VF and not the expected +++ as
the parameter value.

Patient preparation for ECG monitoring

The following tips provide optimal ECG monitoring results but must never replace hospital-approved prac-
tices or the recommendations of the electrode manufacturer.
Follow hospital procedures for proper skin preparation. Dräger recommends Ag/AgCl disposable elec-
trodes. Never use disposable electrodes after their expiration date and make sure that there is enough gel
and that the gel has not dried out.
If QRS detection threshold is configured to Low, P- and T-waves with amplitudes exceeding 0.17 mV may
be interpreted as QRS complexes. P- and T-waves with amplitudes exceeding 0.35 mV when QRS detec-
tion threshold is configured to Normal, may be interpreted as QRS complexes. The algorithm has imple-
mented safeguards to reduce the occurrence of P- and T-wave detection as QRS complexes, however
additional steps can be taken to prevent and/or troubleshoot occurrence: .
– To allow detection of low heart rate conditions under these circumstances, place the lead with the high-
est R-wave in ECG Channel number 1.
– If P- and T-waves are misinterpreted, confirm that the lead with highest R-wave is in ECG Channel
number 1 and set QRS detection threshold to Normal.
– If P- and T-waves continue to be misinterpreted, reposition the electrodes or use a pulse oximeter to
monitor the pulse rate.
Supplement – Infinity M300 and M300+ Series – VG2.4
Infinity M300/M300+ Features for VG2.4
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