GE MAC 800, Operator'S Manual

Page: 63 / 154

Recording a Resting ECG
Because of slow paper speed, pacer pulses cannot be displayed directly on the ECG
recording. For example, with a paper speed of 50 mm/s and a pulse duration of only
0.5 ms, the width of the recorded pacer pulse would be only 0.025 mm.
If Pace Enhance is enabled, the recorder reduces the pulse amplitude and expands
its width to make pacer pulses easier to identify. The system records the pulse with
the correct polarity, a width of 5 ms, and equal amplitude in all leads. Depending on
the polarity of the pacer pulse in leads I and II, the pacer pulse in lead III may be
suppressed. The following figure of an ECG recording with pacer pulses shows the
amplitude of the reverse current.
Recording ECGs During Defibrillation
WARNING:
EQUIPMENT DAMAGE — Damaged cables can cause mechanical problems.
Before connecting the cable to the device, check it for signs of mechanical
damage. Do not use a damaged cable.
For patient safety, use only the original GE Healthcare patient cable.
WARNING:
SHOCK HAZARD — Touching the patient, electrodes, or leadwires during
defibrillation can cause a shock.
During defibrillation, do not touch the patient, the electrodes, or the leadwires.
Observe all defibrillator safety information.
This equipment is protected against the effects of cardiac defibrillator discharge to
allow the ECG trace to return after defibrillation, as required by test standards.
The patient signal input is defibrillation-proof; it is not necessary to remove the ECG
electrodes before defibrillating the patient.
When using stainless steel or silver electrodes, the defibrillator discharge current may
cause the electrodes to retain a residual charge, causing an electrode polarization or
DC offset voltage. This blocks ECG signal acquisition for several minutes. If polarizing
electrodes are used, GE Healthcare recommends that you disconnect the leadwires
from the patient before delivering the shock.
To prevent polarization, GE Healthcare recommends the use of non-polarizing
disposable electrodes with defibrillation recover ratings as specified in AAMI EC12
3.2.2.4 (MMS PN 9623-105 Silver MacTrodes, MMS spec TP9623-003), which requires
the polarization potential of an electrode pair not exceed 100 mV five seconds after a
defibrillation discharge.
2060026-001C MAC™ 800 63