ACLS — Advanced Cardiovascular Life Support — All Questions

What is the correct dose and interval of epinephrine during adult cardiac arrest?

• a.0.5 mg IV/IO every 10 minutes
• b.1 mg IV/IO every 3 to 5 minutes✓
• c.3 mg IV/IO given once
• d.1 mg IV/IO every minute

Epinephrine in cardiac arrest is 1 mg IV/IO every 3 to 5 minutes. Its alpha-adrenergic vasoconstriction raises aortic diastolic pressure and thereby coronary perfusion pressure. In non-shockable rhythms (asystole/PEA), give epinephrine as soon as feasible; in shockable rhythms (VF/pVT), give it after the first shock or two fail to convert the rhythm.

For VF or pulseless VT that persists after defibrillation, which drugs may be considered?

• a.Adenosine or atropine
• b.Diltiazem or verapamil
• c.Calcium or magnesium
• d.Amiodarone or lidocaine✓

The 2025 AHA Guidelines cite a large placebo-controlled trial in which amiodarone and lidocaine each improved survival to hospital admission for shock-refractory VF, without an overall difference in survival to discharge. Routine calcium and magnesium did not improve arrest outcomes.

A stable patient has a regular narrow-complex SVT and vagal maneuvers have failed. What is the first dose of adenosine?

• a.6 mg rapid push, then 12 mg✓
• b.1 mg slow IV push
• c.0.5 mg IV push
• d.12 mg infused over 10 minutes

The FDA-approved adenosine label gives 6 mg as a rapid IV bolus over 1 to 2 seconds, then 12 mg if the tachycardia persists after 1 to 2 minutes, followed by a rapid saline flush; adenosine's very short half-life is why slow injection fails.

Which statement about atropine matches the 2025 adult ALS guidance?

• a.Routine treatment for asystole
• b.First drug for symptomatic bradycardia✓
• c.First-line for stable SVT
• d.Replaces epinephrine in PEA

The 2025 Guidelines cite observational evidence that atropine is effective for symptomatic bradycardia, and it is the first drug used; it is not part of the cardiac arrest pathway (an in-hospital study found no survival benefit for nonshockable rhythms), and SVT is treated with vagal maneuvers and adenosine.

Four minutes have passed since the first 1 mg of epinephrine in an adult cardiac arrest. What is appropriate now?

• a.Give 5 mg to catch up
• b.Wait at least 10 more minutes
• c.Give the next 1 mg dose✓
• d.Stop epinephrine for good

Trials used 1 mg of epinephrine every 3 to 5 minutes, so a repeat dose at 4 minutes fits; larger or more frequent dosing has not shown benefit and may be harmful.

What does epinephrine improve during cardiac arrest, according to the 2025 evidence summary?

• a.ROSC and short-term survival✓
• b.Nothing measurable
• c.Only survival in VF
• d.Proven long-term brain outcomes

Epinephrine increases ROSC and survival to hospital admission; evidence for better neurological outcome is lacking, but it remains standard therapy.

In a shockable rhythm, when is the first epinephrine dose given?

• a.Only after 20 minutes
• b.Never in VF
• c.After CPR and shocks fail✓
• d.Before the first shock

For shockable rhythms, the Guidelines support prioritizing rapid defibrillation and giving epinephrine after initial CPR and defibrillation attempts are unsuccessful.

For VF that persists after defibrillation, which antiarrhythmics improved survival to hospital admission in a large trial?

• a.Amiodarone and lidocaine✓
• b.Diltiazem and verapamil
• c.Magnesium and calcium
• d.Adenosine and atropine

A large placebo-controlled prehospital trial found amiodarone and lidocaine each improved survival to admission, without a difference in survival to discharge.

What does the evidence show about vasopressin in adult cardiac arrest?

• a.It offers no survival edge✓
• b.It is required in asystole
• c.It improves neurologic survival
• d.It should replace epinephrine

Reviews found no survival difference between vasopressin, alone or with epinephrine, and epinephrine alone.

Why is routine calcium not given during cardiac arrest?

• a.It works only in children
• b.It showed no benefit, maybe harm✓
• c.It is too expensive
• d.It cannot be given IV

Trials and reviews found routine calcium did not improve survival or neurological outcome, with a cautionary trend toward harm; hyperkalemia and certain poisonings are exceptions.

When is IV magnesium useful in the ACLS setting?

• a.For torsades de pointes✓
• b.For every VF arrest
• c.For sinus bradycardia
• d.For asystole

Routine intra-arrest magnesium did not improve outcomes, but in torsades de pointes IV magnesium has suppressed and prevented recurrences.

According to the FDA-approved label, what is the first adenosine dose for supraventricular tachycardia?

• a.3 mg IV infusion
• b.6 mg rapid IV bolus✓
• c.12 mg slow IV push
• d.1 mg IM

The adenosine label gives 6 mg as a rapid IV bolus over 1 to 2 seconds, followed by 12 mg if the tachycardia persists after 1 to 2 minutes.

A patient with severe asthma has stable SVT. Which drug is contraindicated?

• a.Adenosine✓
• b.Metoprolol, in all cases
• c.Oxygen
• d.Diltiazem

Adenosine can cause severe bronchospasm in patients with asthma and is therefore contraindicated.

For a patient with a heart transplant and SVT, what adenosine adjustment do the Guidelines note?

• a.Give it intramuscularly
• b.Adenosine never works after transplant
• c.1 mg may be adequate✓
• d.Double the usual dose

Adenosine may have profound effects in patients with central lines or after heart transplant, where 1 mg IV may be adequate.

Atropine is the first drug for symptomatic bradycardia. How does it raise the heart rate?

• a.By slowing AV node conduction
• b.By stimulating β-receptors directly
• c.By shortening the QT interval
• d.By blocking vagal (muscarinic) effects✓

The FDA-approved label describes atropine as a muscarinic antagonist, so it works by blocking vagal slowing of the heart; the 2025 Guidelines cite observational evidence that it is effective for symptomatic bradycardia. When the cause is not vagal, it may fail, and pacing or an epinephrine or dopamine infusion is the next step.

Which IV rate-control dose for atrial fibrillation appears in the 2025 Guidelines' table for diltiazem?

• a.25 mg/kg over 1 hour
• b.2.5 mg/kg over 2 seconds
• c.0.25 mg/kg over 2 minutes✓
• d.0.025 mg/kg as a push

The Guidelines' rate-control table lists diltiazem 0.25 mg/kg IV over 2 minutes, followed by 5–10 mg per hour, avoiding it in hypotension and heart failure.

How fast may IV procainamide be infused?

• a.No faster than 50 mg/min✓
• b.As a rapid push
• c.No faster than 5 mg/hour
• d.No faster than 500 mg/min

The Guidelines note IV procainamide can cause hypotension and must be infused no faster than 50 mg/min.

Why is sodium bicarbonate not given routinely during cardiac arrest?

• a.It is only for children
• b.It cannot mix with saline
• c.It showed no routine benefit✓
• d.It causes VF in every patient

The 2023 focused update found routine sodium bicarbonate in cardiac arrest of no benefit; its use is limited to special circumstances such as hyperkalemia.

A patient in arrest with suspected opioid overdose is receiving high-quality CPR. What is the role of naloxone?

• a.It must be given before any CPR
• b.It reverses VF
• c.It may be given if CPR continues✓
• d.It replaces epinephrine

During arrest from presumed opioid overdose, an opioid antagonist may be reasonable if high-quality CPR is not interrupted; it does not reverse VF.

Why should amiodarone and procainamide not be combined for stable VT?

• a.They cannot be given IV
• b.The combination is too expensive
• c.They cancel each other out completely
• d.They may be arrhythmogenic together✓

The Guidelines advise avoiding co-administration of these antiarrhythmics because their combined effects may be arrhythmogenic, and a defibrillator should be ready.

Which drug route for epinephrine did the 2025 Guidelines remove?

• a.Central venous
• b.Through the endotracheal tube✓
• c.Intraosseous
• d.Intravenous

Administering intra-arrest medications via an endotracheal tube was removed because it produces low blood concentrations and unpredictable effects.