Page 471 - Critical Care Nursing Demystified

456 CRITICAL CARE NURSING DeMYSTIFIED

Chapter 4

1. C. Sinus tachycardia is normal except for the rate, which is over 100. First-degree AV
block has a prolonged PRI and everything else is normal. In ventricular tachycardia, the
ventricular rate is fast, but there are no P waves and the QRS is wide and bizarre.
2. B. The P-to-P interval shows us that the P waves are regular and marching on time.
The atrial rate refers to counting the P waves and multiplying them by 10. Ventricular
conduction is the QRS measurement, and ventricular repolarization is looking at the
T wave to see that it is upright, rounded, and symmetrical.
3. C. Q wave is the first negative wave after the P wave. The ST segment is after the QRS
and indicates the pause between ventricular depolarization and repolarization. The R
wave is the first positive wave after the P wave, and the S wave is the first negative wave
after the R wave. Deep Q waves are indicative of an MI if they are consistent in certain
leads that look at the heart.
4. D. Atrial flutter is known by its regular, multiple P waves that all march out on time and
are known as flutter waves.
5. D. Second-degree heart block, Mobitz type I or Wenckebach, is known for its charac-
teristic prolongation of the PRI until there is a blocked or nonconducted P wave. In
complete heart block the atrial and ventricular rhythms are regular because the atria
and ventricles beat independently. First-degree heart block is prolongation of the PRI.
Mobitz II has a consistent PRI and some QRS are not conducted. 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.
6. B. Because this situation is an emergency and early defibrillation is critical, the nurse
uses the anterior posterior pad position. Time wasted on CPR will delay defibrillation
time, so getting the defibrillator ready is a priority. CPR can be performed later. A strip is
only needed in a cardioversion as the machine is synched to avoid the T wave and fire
on the R.
7. B. The mA is the amount of electricity applied to the heart. It needs to be turned up to
capture the heart when the heart is brady or tachy. The rate refers to how fast the pace-
maker is set. The synchronous function is when the pacer fires only when the heartbeat
slows down too much or speeds up too fast. The asynchronous function is set so that
the pacer is firing all the time.
8. A. Atropine is used to help increase the heart rate. The other medications are used in
VT or VF.
9. B, C, and E. The nurse’s role is to prevent sepsis by suctioning, turning, and providing
infection control. An NGT is inserted to induce mild hypothermia until a cooling blan-
ket can be obtained. Antiarrhythmics can be common as the heart may still be cranky.
Antipyretics are not needed as patients do not have fevers with mild hypothermia.
10. B. A patient may not breathe well after a cardioversion, so a BVM is important to have
on hand. A chest tube is not needed as pneumothorax is not a complication of this
procedure. The defibrillator is placed on the synchronous mode to avoid the T wave
and to fire on the R wave.