Page 210 - Critical Care Nursing Demystified

Chapter 4 CARE OF THE PATIENT WITH CRITICAL CARDIAC RHY THM DISTURBANCE NEEDS 195

the time, so make sure the patient has no underlying rhythm that comes
through.
• Capture – when the pacer causes the heart to beat; usually signified by a
pacer spike and the chamber paced (i.e., pacer spike and P wave for atrial
pacing; pacer spike and R wave for ventricular pacing).
• Threshold – the minimum amount of voltage (mA) needed to consistently
capture the heart.
• mA – amount of electricity needed to capture the heart.

NURSING ALERT

An asynchronous pacing mode is only used when there is no chance that the pa-
tient’s own rhythm will break through and compete with the pacer. If the pacer fires

on the patient’s own T wave, it could create electrical chaos and lead to ventricular
tachycardia or fibrillation.

The Pacer Codes Downloaded by [ Faculty of Nursing, Chiangmai University 5.62.158.117] at [07/18/16]. Copyright © McGraw-Hill Global Education Holdings, LLC. Not to be redistributed or modified in any way without permission.
The critical care nurse needs to know about the five pacing codes that tell
about different pacer functions. These are divided into chamber paced, cham-
ber sensed, response to sensed event, rate modulation, and multisite pacing.
Table 4–7 helps identify the modes of pacing.
The first three letters of the code refer to the prevention of bradycardias in
the pacemaker. The first letter indicates the chamber that is paced or where the

TABLE 4–7 Codes of Pacemakers
Chamber Paced Chamber Response to Rate Modula- Multisite
(First Letter) Sensed Sensed Event tion (Fourth (Fifth
(Second Letter) (Third Letter) Letter) Letter)
O – none O – none O – none O – none O – none
A – atrial A – atrial T – triggered R – rate A – atrial
modulated
V – ventricular V – ventricle I – inhibited V – ventricle
D – dual (both D – dual D = T and I D – dual
atrial/ventricular)
S – single (atrial/ S – single
ventricular)