Apply ECG leads and electrodes and adjust ECG size and lead for a convenient waveform to display an R wave. Verify a proper R wave detection. The heart shape symbol flashes with each R wave when proper detection is taking place.
Attach MFE pads Anterior and posterior positions:
Place pad left midclavicular line and fourth intercostal space. Avoid nipple.
Pace pad under the left scapula next to the spine.
If unable to place anterior or posterior then revert to normal defibrillation positions.
MFE pads should be replaced after 8 hours (2 hours if using radiolucent stat-padz).
Demand pacing using the M series Monitor Defibrillator. The unit monitors the patient pulse via the ECG cable and delivers selected energy level only when the patient’s intrinsic rate falls below the set pacer rate. If the rate does not
fall below this rate the pacer will not send a stimulus.
Turn selector switch to PACER. Display as per figure 1.
Turn the PACER RATE knob clockwise until screen displays the desired pacing rate. Variable rate from 30-180 pulse per minute (ppm).
Verify that pacing markers display on the ECG trace.
Turn the PACER OUTPUT (milliamps) knob clockwise slowly until ventricular capture is consistently achieved. Generally the amount of current varies widely however the range is normally between 50-90mA. The maximum current on the external pacer
Increase pacer output until symptoms resolve or rate of 100ppm is reached.
Note: when the unit is switched out of Pacer mode into defib or monitor modes and back again the pacer settings will remain unchanged. If the unit is turned off for more than ten seconds the pacer default settings will be restored.
Check for electrical capture by the presence of a pacing spike followed by a widened QRS complex (response to the stimuli), the loss of any underlying intrinsic rhythm, and the appearance of an extended, and sometimes enlarged T wave.
Check for mechanical capture by taking a pulse on the femoral, brachial or radial artery. Mechanical capture will be evident by a palpable pulse, rise in blood pressure and improvement in conscious state (if not sedated and paralysed).
Caution. If you suspect an inaccurate beat detection, change the selected lead to view the heart from a different angle. If this does not solve the suspected problem, change the selected size.
For certain patients at risk of symptomatic bradycardia, it may be advisable to use the unit in standby mode.
In this mode the unit automatically provides a pacing stimulus whenever the patient’s pulse drops below a predetermined level.
Patient’s ECG must be monitored using ECG leads and patient cables.
Establish effective pacing
Note: mA output at capture and run an ECG strip to document ECG morphology during capture.
Set mA output to 10% higher than the minimum mA output necessary to effect consistent ventricular capture.
Turn the pacing rate (ppm) below the patient’s pulse. The pacing rate should be set at a level sufficient for adequate cardiac output.
Check threshold periodically
During asynchronous pacing the M series unit delivers an electrical stimulus regardless of patient’s pulse. If any of the following conditions are present, it may be necessary to operate the pacemaker asynchronously:
ECG electrodes are not available.
ECG artefact is present.
Patient has Ventricular Tachycardia.
Asynchronous pacing should only be performed in emergency situations when there are no other alternatives.
If ECG cables are used during asynchronous pacing, ECG waveforms display and you can determine whether capture was achieved. While asynchronous pacing without ECG cables, no ECG activity displays, so other means for determining capture such as checking pulse are necessary.
To pace asynchronously:
Turn Selector Switch to PACER
Press the Async Pacing On/Off softkey
Confirm that the ASYNC PACE message displays
While pacing a patient you should occasionally check the patient’s underlying rhythm to see if pacing is still required. This can be done quickly using the 4.1 Button.
Whilst the 4.1 button is held down the pacer delivers an electrical impulse at one quarter the displayed rate. This enables you to see the patient’s underlying rhythm while safely pacing. Releasing the button will return the unit to normal pacing.
Explain procedure; consider changing pad placement to anterior /posterior positions, initiate pain management.
Diaphragmatic pacing is relatively frequent and may require sedation and ventilatory support at times.
Pacing problems, failure to:
Where pacing spikes are not followed by a broad QRS complex, the current is insufficient to stimulate the heartbeat.
Increase current and consider other causes that might alter the threshold such as hypoxia, metabolic and electrolyte derangements.
Another possibility is that the patient is moribund.
Occurs when the pacer interprets artefact as intrinsic rhythm and inhibits itself from firing; this may result in blood pressure drop.
Reposition leads or electrodes and select the non-demand mode.
When the pacer fails to detect intrinsic activity and paces inappropriately.
Change the lead, and increase ECG size or reposition the electrodes.
Document the rate threshold, output, underlying rhythm and any adjustments made.