Cardiac Monitoring

7/28/2019 Cardiac Monitoring

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DefinitionThe cardiac monitor is a device that shows the heart's electrical activity as a wave

pattern on a monitor. It is a bedside monitor.

PurposeThe cardiac monitor continuously shows the cardiac rhythm and sends the

electrocardiogram (EKG) tracing to a main monitor in the nursing station. Most

commonly used in emergency rooms and critical care areas, cardiac monitoring

allows for continual observation of several patients. Aside from monitoring

cardiac patients, continuous monitoring is useful for observation of postoperative

patients, patients with severe electrolyte imbalances, and other unstable

patients. Continuous cardiac monitoring allows for prompt identification andinitiation of treatment for cardiac arrhythmias and other conditions.

PrecautionsThe American Heart Association warns of potential interference between

some pacemakers and cardiac monitors. Minute ventilation rate-adaptive

pacemakers can occasionally interact with certain cardiac monitoring and

diagnostic equipment, causing the pacemakers to pace at their maximum-

programmed rate. Minute ventilation is sensed in rate-adaptive pacemakers bytechnology known as bioelectric impedance measurement (BIM). Many medical

devices in addition to pacemakers use this technology. When one of these devices

is used on a patient with an active, minute ventilation rate-adaptive pacemaker,

the pacemaker can erroneously interpret the mixture of BIM signals created in

the patient, resulting in an elevated pacing rate. Cardiac monitors,

echocardiograph equipment, apnea monitors, respiration monitors, and external

defibrillators are common devices that may use BIM technology.

DescriptionThe monitor provides a visual display of the patient's heart rhythm, which is

particularly useful information during heart attacks, when patients can develop

lethal cardiac arrhythmias. The monitor sounds an alarm if the patient's heart rate

goes above or below a predetermined number. An automatic blood pressure cuff


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and a pulse oximeter, which measures the oxygen saturation in the blood, are

also included with some monitors.

Equipment required for continuous cardiac monitoring includes:

cardiac monitor monitor cable leadwires electrodes dry washcloth or gauze pad alcohol sponges

Cardiac monitors display vital information for patients in the intensive care

unit. (Photograph by Hank Morgan. Science Source/Photo

Researchers. Reproduced by permission.)

PreparationAll electrical equipment and outlets are grounded to avoid electrical shock and

artifact (electrical activity caused by interference). The nurse should plug in the

monitor, turn on power, and connect the cable if not already attached. He or she

should connect the lead wires to the proper position and ensure that color-coded

wires match the color-coded cable. If the device is not color coded, the right arm

(RA) wire should be attached to the RA outlet, the left arm (LA) wire attached to

the LA outlet, and so forth. The nurse should open the electrode package, and

attach an electrode to each lead wire. The hands should be washed and the

procedure should be explained to the patient. Privacy should be ensured for thepatient, and the patient should be clean and dry to prevent electrical shock.

Next, the chest should be exposed and the sites selected for electrode placement.

Using the rough patch on the electrode, a dry washcloth, or gauze pad, each site

should be rubbed briskly until it reddens, but care should be taken not to damage

or break the skin. Dead skin cells are removed in this manner, thereby promoting


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better electrical conduction. Patients who are extremely hairy may need to be

shaved prior to application of the electrodes. An alcohol pad is used to clean the

sites in patients with oily skin. Areas should dry completely to promote good

adhesion. Alcohol should not become trapped beneath the electrode, as this can

lead to skin breakdown. In addition to oily skin, diaphoretic skin can causeinterference in the recording. To minimize this interference, the electrode site

should be rubbed with a dry 4x4 gauze pad before application. The backing of the

electrode should be removed, and the gel inspected. If the electrode

has dried out, which can happen if the electrode package is opened before

immediate use, it should be discarded and another used. The nurse should apply

one electrode to each site, press one side of the electrode against the skin, and

pull gently. Then, the opposite side of the electrode should be pressed against the

skin. The nurse should press two fingers on the electrode in a circular pattern to

affix the gel and stabilize the electrode, then repeat for each electrode. To avoid

potential artifact, do not place the electrodes on bony prominences or hairy

areas.

After careAfter placing all electrodes, the nurse should observe the monitor and evaluate

the quality of the tracing, mak ing size and tracing position adjustments as

needed. He or she should confirm that the monitor is detecting each heartbeat by

taking an apical pulse and comparing the pulse to the digital display. The upper

and lower alarm limits should be set according to institutional policy, and the

alarm activated. A rhythm strip should be recorded for the medical record, and

labeled with patient name, room number, date, time, and interpretation of the

strip.

ComplicationsThere is a potential for skin breakdown at the electrode placement site. Thepatient may be allergic to the adhesive used, or the electrode may have been left

on the skin too long. The electrodes should be removed and new electrodes

applied, using hypoallergenic electrodes if necessary.


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INTERPRETATIONS/RESULTSA normal cardiac tracing shows a regular rate and rhythm with no deviations in

the QRST complex (the combined waves of an electrocardiogram). Abnormal

results may include bradycardia, or tachycardia, accompanied by the alarm. Q

waves (the short initial downward stroke of the QRST complex) are abnormal, and

may or may not signal an infarction.

Some causes of noninfarction Q waves are:

ventricular hypertrophy ventricular preexcitation (Wolf-Parkinson-White syndrome) cardiomyopathies pulmonary embolism incomplete left bundle branch block

Causes of changes in ST Segment (part of the EKG between the QRS complex and

the T wave) and T Wave (deflection in an EKG that represents electrical activity of

the ventricular repolarization) include:

aberrant conduction amyloidosis bundle branch block cardiomyopathy cocaine vasospasm electrolyte disturbances intracranial hemorrhage myocardial metastases myocarditis paced rhythm pancreatitis or acute abdomen pericarditis physical training Printzmetal's angina pulmonary embolism tachycardia ventricular aneurysm ventricular hypertrophy ventricular rhythms Wolff-Parkinson-White syndrome


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Alarm signals are abnormal and must be investigated. A false high alarm rate may

be caused by skeletal muscle activity or by the monitor incorrectly interpreting

large T waves as a QRS complex, which would double the true heart rate. The

electrodes should be repositioned as needed to ensure that the electrode is not

over a major muscle mass and that QRS complex is larger than the T wave. A falselow alarm rate may be due to patient movement, or poor contact between

electrodes and skin. Electrodes should be reapplied as needed. Artifact is a

common abnormal finding, and may be caused by improperly placed electrodes,

patient movement, static electricity, seizures, anxiety, or chills. The position of

electrodes should be checked and static-causing bed linen changed. The cables

should not have exposed connectors.

Health care team rolesCardiac monitoring is usually ordered by a physician. A nurse practitioner or

physician assistant can place the electrodes on thepatients body. A nurse

provides ongoing care during the monitoring, assesses patient to determine

hemodynamic effects of rhythms, and intervenes for dysrhythmias as

appropriate. The nurse also instructs the patient and family about the cardiac

monitor's use.

BIBILIOGRAPHYhttp://www.enotes.com/cardiac-monitor-reference/cardiac-monitor-171807
http://www.enotes.com/cardiac-monitor-reference/cardiac-monitor-171807http://www.enotes.com/cardiac-monitor-reference/cardiac-monitor-171807http://www.enotes.com/cardiac-monitor-reference/cardiac-monitor-171807

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Cardiac Monitoring