To Zap or Not to
Zap
Keith Martin, RN, BSN, BSc.
Clinical Nur Educator, ER/ICU
毛蚶子MD10
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Disclaimer: this handout contains a lot of information that is protocol oriented. Protocols are not examinable in the first year MD/DMD curriculum. Further, a lot of information contained is handout is beyond the scope of the first year CV block. Plea refer to the weekly objectives and the weekly quizzes to help you determine what is included in the curriculum of the block. Questions relating to the content of this handout should be emailed to the author. The author is responsible for accuracy. J Waechter
猕猴桃如何保存To Zap or Not to Zap
•80% of all arrests are found in V.tach or V. fib
•CPR prolongs life, it doesn’t save it
•Defibrillation is the most cost effective method of terminating V. Fib.
•Earlier the zap = better the survival rate.
•As critical care nurs it is one of our many responsibilities to know when to defibrillate, when to cardiovert, and when to leave the patient alone.
First the Basics:
Arrhythmia:
•Abnormal electrical activity of the heart.
•The one we are concerned about here are:
o Ventricular Fibrillation: A chaotic arrhythmia that caus the heart to quiver rather than contract in a coordinated fashion. No effective pul or
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blood pressure is generated, unconsciousness is nearly immediate, and
death follows within minutes if the arrhythmia is not halted.
o Ventricular Tachycardia: This rhythm is usually regular to slightly irregular. It is characterized by a rapid, bizarre wide QRS complex usually
around 150 to 250 beats per minute. The symptoms of V. Tach depend
upon the rate, duration, and verity of the underlying heart dia. The
immediate significance of this rhythm to nurs depends on the
hemodynamic stability of the patient and the possibility of degenerating
into ventricular fibrillation.
o Supraventricular Tachycardia: SVT is characterized by it narrow QRS complex ventricular tachycardia with no measurable P wave, since it is
usually obscured by the preceding T-wave. The rate is regular at ~ 150-
250 beats per minute. Usually brought on by stress, smoking, caffeine, or
over exertion. Sometime the patients will feel palpations, nervousness,
anxiety and even angina. This rhythm can lead to heart failure or shock飞的笔顺
depending upon the verity of the symptoms and the duration.
o Atrial Fibrillation: In this rhythm, the atrial rate is above 350 contractions per minute. It is characterized by a baline which is coarly or finely
irregular. There is no P wave preceding the QRS complex, which is
irregular and may be slow or rapid.
o Atrial Flutter: This rhythm is characterized by its saw tooth pattern of the P waves. The atrial rate is constant between 250 and 400 contractions
per minute. The ventricular rate will vary with the degree of the block.
The chief concern here is losing the block and having all the atrial beats
conducting to the ventricles.
Electrical Therapy:
•Electrical therapy or shocking the heart completely depolarizes the myocardium so that the natural pacemaker can resume.
•It’s not “jump starting” the heart, it’s “jump stopping” it.
•The machine ud in electrical therapy is called the defibrillator.
Defibrillator:
• A device that can deliver electrical current to the heart to treat arrhythmias. All of the defibrillators in this hospital are portable and have electrocardiographic
普宁豆腐monitoring capacity.
•The output of defibrillators is called measured in joules
o The amount of energy (J) relead per cond.
•There are two types of defibrillators:
o Biphasic Waveform (Lifepak 12 and 20): Pattern of electrical flow where the current revers direction in the middle of the waveform, flowing first
from one electrode pad, through the heart, to the cond electrode pad,
and then from the cond pad, through the heart, to the first. A biphasic
waveform requires less energy than the monophonic waveform to achieve
superior defibrillation efficacy. Biphasic waveforms are considered the
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standard of care and intervention of choice.
o Monophonic Waveform (Hewlett Packard): Pattern of electrical flow where the current, throughout the pul, flows in one direction, from one
electrode pad, through the heart to the other electrode pad.
•Factors to consider when using a defibrillator:
o Transthoracic resistance
Amount of joules
Electrode size (paddles vs pads)
Number of shocks
Electrode pressure = 25 lbs
Skin preparation = gel vs saline
o Electrode Position
If the patient has a permanent pacemaker, paddles/pads must be
10 cm away from pacer.
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Paddles
•The anterior-posterior scheme is the preferred scheme for
long-term electrode placement. One electrode is placed over
the left precordium (the lower part of the chest, in front of the
heart). The other electrode is placed on the back, behind the
heart in the region between the scapula. This placement is
preferred becau it is best for non-invasive pacing.
•The anterior-apex scheme can be ud when the anterior-
posterior scheme is inconvenient or unnecessary. In this系统分析员
scheme, the anterior electrode is placed on the right, below
the clavicle. The apex electrode is applied to the left side of
the patient, just below and to the left of the pectoral muscle.
This scheme works well for defibrillation and cardioversion,
as well as for monitoring an ECG.
Pads
•Follow directions on package and pads themlves.
