A 68-year-old patient in the ICU suddenly develops ventricular fibrillation (VF) on the cardiac monitor. The nurse immediately begins CPR and calls for the code team. When the defibrillator arrives, what is the most appropriate initial energy level for defibrillation in this adult patient?
1120 joules
2200 joules✓ 정답
3300 joules
4360 joules
해설
According to ACLS guidelines, the initial defibrillation energy for VF in adults is 200 joules for biphasic defibrillators. Other options are incorrect as they do not align with standard protocols.
Clinical Judgment
This question asks about the initial energy setting for defibrillation that must be immediately applied to a patient with ventricular fibrillation in a Code Blue situation. The key is to apply the standard protocol according to the latest ACLS (AHA, 2020) guidelines. The standard initial energy for the biphasic defibrillator currently used in most medical institutions is 200 joules (J). This setting balances effective defibrillation with minimizing the risk of myocardial damage. If the first shock is ineffective, subsequent shocks are delivered at the same or higher energy (e.g., 200J → 300J) according to the manufacturer's recommendation.
Memory Tip:
An easy-to-remember tip is "Biphasic = Best start at 200." This means it is best to start with 200 joules on a biphasic machine. Monophasic defibrillators use 360J, but they are now rarely used.
KR vs US:
The ACLS guidelines and defibrillation protocols themselves are identical in Korea and the US, based on AHA standards. The difference may lie in the practical environment. The US NCLEX tests based on the absolute standard of the latest AHA guidelines, and Korean nurses must think according to the exam and latest guideline standard (biphasic 200J), not the older equipment settings they may be familiar with at their hospital (e.g., monophasic 360J).
임상 시나리오
Clinical Practice Guide
1. Defibrillation: Treatment for disorganized rhythms (e.g., VF, pulseless VT). Delivers an unsynchronized electrical shock to the heart.
2. Synchronized Cardioversion: Treatment for organized fast rhythms (e.g., A-fib, VT with pulse). Delivers an electrical shock synchronized to the heart's R wave. Energy settings differ.
3. Minimize interruptions in chest compressions before and after defibrillation. Continue CPR even during charging.
Caution:
In SATA (Select All That Apply) questions, if asked to "choose the correct statements about defibrillation," correct knowledge includes: "The initial energy is 200J for a biphasic defibrillator," "Defibrillation is applied to pulseless VT," and "Continue CPR during charging." A common mistake is confusing defibrillation with synchronized cardioversion, or choosing 360J while ignoring the difference between monophasic and biphasic devices.
핵심 개념
Ventricular Fibrillation — Ventricular fibrillation. A life-threatening arrhythmia in which the myocardial fibers of the ventricles contract rapidly and uncoordinatedly, failing to produce effective cardiac output and leading to cardiac arrest.
Defibrillation — Defibrillation. A treatment that delivers an unsynchronized electrical shock to the heart to terminate disorganized, life-threatening rhythms such as ventricular fibrillation (VF) or pulseless ventricular tachycardia (pulseless VT).
Biphasic Defibrillator — Biphasic defibrillator. A type of defibrillator in which the current direction reverses once during the shock, allowing effective defibrillation with lower energy compared to monophasic types, and is currently used as the standard.
ACLS (Advanced Cardiovascular Life Support) — Advanced Cardiac Life Support. An educational program for healthcare professionals that includes systematic treatment protocols and techniques for cardiac arrest and other cardiovascular emergencies.
Joule — Joules. A unit of energy, representing the amount of electrical energy delivered to the heart during defibrillation.