TRANSCUTANEOUS CARDIAC PACING

The LIFEPAK 8 QUIK-PACE external transthoracic pacing cassette is an external cardiac pacemaker for emergency use. It's power is derived from the LIFEPAK 8 defibrillator. The monitor displays both intrinsic and pacemaker-derived complexes. It is capable of either demand or non-demand (asynchronous) pacing and has controls for adjusting both the rate and the current levels.

The pacemaker is implemented using two disposable electrodes which are self-adhering. The anterior electrode is placed on the left anterior chest, halfway between the xiphoid process and the left nipple, with the upper edge below the nipple line. The posterior electrode is placed on the left posterior chest beneath the scapula and lateral to the spine.

The RATE knob adjusts the pacing rate from forty to ninety beats per minute in ten-beat-per-minute increments.

The current level is adjusted with the CURRENT knob and is variable from zero to two-hundred milliamps.

The buttons labeled DEMAND and NON- DEMAND are self-explanatory and are mutually exclusive.

The START-STOP button begins pacing. This button must be off before changing pacing modes.

When instituting artificial pacing, the patient and the monitor of the LIKEPAK 8 must be continuously assessed.

If the current level is too low you will see pacemaker "spikes" with no resultant QRS complexes. While watching the monitor, slowly increase the current level until the pacemaker "spikes" result in consistent "capture" of the ventricle (i.e. each spike should be followed by a QRS complex).

Unfortunately, this may result in some discomfort to the patient but, in most cases, the patient does not seem to mind too much as the intervention is usually either prophylactic (in which case very little pacing actually occurs anyway as the RATE is set below the patient's intrinsic rate) or therapeutic (in which case the patient is quite ill and external pacing is continued only until a temporary transvenous pacemaker can be inserted.

Generally, if the patient is pacemaker-dependent, the rate would be set nominally at 70 beats per minute. If the pacemaker is for prophylaxis, the rate would be set around 50 beats per minute and pacing would not occur until the patient's rate fell below this value.

This is all there is to it (in a nutshell). The device is very easy to use and, as prophylaxis, has been a boon in that it saves the patient the discomfort and risks of insertion of a transvenous pacing catheter. As always, clinical judgement should prevail when making adjustments to the pacing parameters. For patient comfort, just remember to set the CURRENT at the lowest possible effective value.

- Graham Miles

This page last updated July 21, 1998