DC Dysrhythmia Equipment & Technology 1 — Questions and Answers
Question 1: What is the primary difference between defibrillation and synchronized cardioversion?
- Defibrillation delivers a shock at any point in the cardiac cycle, while cardioversion is timed to the R wave (Correct answer)
- Defibrillation uses lower energy than cardioversion
- Cardioversion is used only for ventricular fibrillation
- Defibrillation requires sedation while cardioversion does not
Correct answer: Defibrillation delivers a shock at any point in the cardiac cycle, while cardioversion is timed to the R wave
Defibrillation delivers an unsynchronized shock at any point in the cardiac cycle, while synchronized cardioversion is timed to the R wave to avoid the T wave vulnerable period.
Question 2: Which energy level is recommended for biphasic defibrillation of ventricular fibrillation per current AHA guidelines?
- 50–100 joules
- 120–200 joules (Correct answer)
- 300–360 joules
- 400–450 joules
Correct answer: 120–200 joules
Current AHA guidelines recommend 120–200 joules for biphasic defibrillation, which achieves effective termination of VF at lower energy than monophasic waveforms.
Question 3: Where should defibrillator pads be placed for standard anterior-lateral positioning?
- Right upper chest below the clavicle and left lower lateral chest (Correct answer)
- Center of the chest and left shoulder
- Both sides of the lower chest
- Right lower chest and left upper chest
Correct answer: Right upper chest below the clavicle and left lower lateral chest
Standard anterior-lateral pad placement positions one pad on the right infraclavicular area and the other on the left lower lateral chest so current passes through the heart.
Question 4: Which alert indicates poor electrode-to-skin contact during defibrillation?
- Wandering baseline alarm
- 60-cycle interference alarm
- High impedance alert (Correct answer)
- Motion artifact warning
Correct answer: High impedance alert
A high impedance alert signals inadequate electrode-to-skin contact, which reduces current delivery and must be corrected before attempting defibrillation.
Question 5: What is the recommended paddle pressure when using hard paddles for manual defibrillation?
- 5 pounds
- 10 pounds
- 25 pounds (Correct answer)
- 50 pounds
Correct answer: 25 pounds
Approximately 25 pounds of firm paddle pressure reduces transthoracic impedance by eliminating air gaps between paddle and skin, improving current delivery to the heart.
Question 6: Which waveform type is used in modern automated external defibrillators (AEDs) and delivers current in two phases?
- Monophasic damped sinusoidal
- Biphasic truncated exponential (Correct answer)
- Uniphasic square wave
- Monophasic quasi-sinusoidal
Correct answer: Biphasic truncated exponential
Modern AEDs use a biphasic truncated exponential waveform that delivers current in two opposite-polarity phases, allowing effective defibrillation at lower energy levels.
DC Dysrhythmia Equipment & Technology 1
What is the primary difference between defibrillation and synchronized cardioversion?