Dropouts - Philips IntelliVue TRx Instructions For Use Manual

Optimizing ECG Measurement Performance
Monitoring
Considerations

Dropouts

6-30
ECG Monitoring
Clinicians will tend to see more motion related artifact on the ECG of
ambulatory patients than on patients that are restricted to a bed. Proper skin
preparation and electrode application are very important in reducing this
problem.
Problems with the ECG signal stem from two main sources:
1. Frequency-related sources resulting in dropouts from signal disturbances
and loss of signal.
2. Patient-related sources with noise on the waveform caused by clinical
considerations such as poor skin prep, dry electrodes, and poor electrode
adhesion, as well as by patient motion and muscle artifact.
Even in complex situations where problems overlap, most of the time you'll be
able to greatly enhance performance by taking corrective action.
• Patient should be restricted to the designated coverage area. Monitoring
performance will degrade if patients go outside the radius of coverage of
the receiving wireless network.
• A patient location strategy is critical to a telemetry system. If a life-
threatening event occurs, the clinician must be able to locate the patient
quickly. The importance of this increases as the coverage area increases.
• Frequency management is the responsibility of the hospital. Philips
Medical System has no control over the RF environment in the hospital.
If interference exists at the operating frequencies of the telemetry
equipment, telemetry performance will be affected. Careful selection of
frequencies for all wireless devices used within a facility (transceivers,
other wireless medical devices, etc.) is important to prevent interference
between them.
Because the IntelliVue Telemetry System is a wireless system, under certain
frequency conditions dropouts can occur. Dropouts result from a weak signal or
RF interference, and appear on the waveform when the signal "drops" to the
bottom of the channel for a minimum of 200 ms. If dropouts are frequent
enough to affect the heart rate count, the "Cannot Analyze ECG" or "Cannot
Analyze ST" technical alarm occurs. If there are enough dropouts to cause