ACLS — Advanced Cardiovascular Life Support — All Questions

What is the recommended chest compression rate for high-quality CPR in an adult?

• a.60 to 80 compressions per minute
• b.80 to 100 compressions per minute
• c.100 to 120 compressions per minute✓
• d.120 to 140 compressions per minute

Current AHA guidelines call for a compression rate of 100 to 120 per minute. Rates slower than 100 reduce coronary and cerebral perfusion, while rates faster than 120 shorten the recoil/filling phase and reduce the depth actually achieved, so the diastolic filling of the heart suffers. Staying inside the 100-120 window balances forward blood flow with adequate ventricular filling.

What is the correct chest compression depth for an average adult?

• a.At least 2.5 cm (1 in)
• b.At least 5 cm, not over 6 cm✓
• c.At least 4 cm (1.5 in)
• d.At least 7.5 cm (3 in)

Evidence behind the 2025 AHA Guidelines links survival with compression depths of at least 5 cm (about 2 inches) and reduced survival with excessive depth over 6 cm (about 2.4 inches). Shallower compressions move too little blood; deeper ones risk injury without benefit.

To maximize the chest compression fraction, interruptions in compressions should be limited to less than:

• a.5 seconds
• b.10 seconds✓
• c.20 seconds
• d.30 seconds

Pauses in compressions (for rhythm checks, ventilation, or defibrillation) should be kept under 10 seconds. The goal is a chest compression fraction of at least 60%. Every second without compressions drops coronary perfusion pressure, which then takes several compressions to rebuild, so minimizing hands-off time directly improves the odds of ROSC.

Once an advanced airway (e.g., endotracheal tube) is in place during cardiac arrest, how should ventilations be delivered?

• a.Pause compressions and give 30:2 cycles
• b.1 breath every 3 seconds with pauses
• c.10 per minute, compressions continuing✓
• d.20 per minute synchronized to compressions

With an advanced airway, compressions continue without pausing for breaths, and ventilations are given at about 10 per minute (1 every 6 seconds); no faster rate has been shown superior, and excessive ventilation lowers cardiac output.

What is the most reliable method to confirm and continuously monitor correct endotracheal tube placement during CPR?

• a.Auscultation alone
• b.A chest x-ray after the code
• c.Pulse oximetry readings
• d.Waveform capnography✓

In the studies cited by the 2025 AHA Guidelines, waveform capnography was 100% specific for confirming endotracheal tube position during cardiac arrest; auscultation and oximetry are less reliable, and an x-ray after the code is too late.

During bag-mask ventilation, delivering breaths too rapidly and forcefully is harmful mainly because it:

• a.Reduces cardiac output✓
• b.Cools the patient too quickly
• c.Improves oxygenation beyond need
• d.Has no measurable effect

The 2025 AHA Guidelines state that excessive ventilation can cause gastric inflation, regurgitation, aspiration and decreased cardiac output; each breath should only produce visible chest rise.

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.

Which pair of rhythms is treated with defibrillation (i.e., is 'shockable')?

• a.Asystole and pulseless electrical activity (PEA)
• b.Ventricular fibrillation and pulseless ventricular tachycardia✓
• c.Sinus bradycardia and first-degree AV block
• d.Normal sinus rhythm and atrial flutter with a pulse

Only ventricular fibrillation (VF) and pulseless ventricular tachycardia (pVT) are shockable — defibrillation can reset the chaotic ventricular activity so an organized rhythm can resume. Asystole and PEA are non-shockable; they are treated with CPR, epinephrine, and correction of reversible causes. Delivering a shock to asystole or PEA provides no benefit.

The monitor shows a flat line, confirmed in two leads, in a pulseless patient. The correct action is to:

• a.Defibrillate immediately
• b.Perform synchronized cardioversion
• c.CPR and epinephrine; no shock✓
• d.Give adenosine 6 mg rapid IV push

Asystole is a nonshockable rhythm: continue high-quality CPR, give epinephrine as early as possible, and look for reversible causes. Shocks and cardioversion do not treat asystole.

A stable patient has a regular narrow-complex tachycardia at 180 bpm; vagal maneuvers have not worked. The next appropriate step is:

• a.Defibrillate the patient
• b.Give adenosine 6 mg by rapid IV push✓
• c.Give atropine 1 mg IV
• d.Give epinephrine 1 mg IV push

A regular narrow-complex tachycardia that persists after vagal maneuvers in a stable patient is treated with adenosine 6 mg rapid IV push (then 12 mg if needed). This most likely represents a re-entrant SVT, and adenosine's transient AV nodal block can break the circuit. Defibrillation, atropine, and arrest-dose epinephrine are all inappropriate for a stable, perfusing SVT.

A patient collapses in witnessed VF arrest and a defibrillator is immediately available. The highest priority is to:

• a.Establish IV access and give epinephrine
• b.Intubate the patient first
• c.Shock now, then resume CPR✓
• d.Give amiodarone before any shock

When VF is witnessed with a defibrillator immediately available, the 2025 Guidelines say defibrillation can be performed immediately; compressions resume at once after the shock. Drugs come after initial CPR and shocks fail.

The monitor shows an organized rhythm but the patient has no pulse (PEA). Management includes:

• a.Immediate defibrillation
• b.Synchronized cardioversion
• c.Adenosine 6 mg rapid IV push
• d.CPR, epinephrine and a cause search✓

PEA is nonshockable: high-quality CPR, early epinephrine and a search for reversible causes such as hypovolemia, hypoxia, tamponade, pulmonary embolism, electrolyte problems and toxins.

Immediately after delivering a defibrillation shock, the team should:

• a.Check a pulse for 30 seconds
• b.Resume compressions right away✓
• c.Reanalyze the rhythm at once
• d.Give two breaths before compressions

Immediate resumption of compressions after a shock shortens the perishock pause and improves the compression fraction; the rhythm is rechecked after about 2 minutes of CPR.

A patient has a heart rate of 38 with hypotension and altered mental status. What is the first-line drug?

• a.Adenosine
• b.Atropine✓
• c.Amiodarone
• d.Metoprolol

Atropine has been shown effective for symptomatic bradycardia in observational studies and is the first drug used; the other options are tachycardia or rate-slowing drugs.

A patient with wide-complex tachycardia has a pulse but is hypotensive and confused. The appropriate treatment is:

• a.Unsynchronized defibrillation
• b.Synchronized cardioversion✓
• c.Adenosine only, then observe
• d.No treatment; continue to observe

An unstable tachycardia WITH a pulse (hypotension, altered mental status, ischemic chest pain, or signs of shock) is treated with immediate synchronized cardioversion. Synchronization times the shock to the R wave to avoid delivering energy during the vulnerable T-wave period, which could induce VF. Unsynchronized defibrillation is reserved for pulseless VT/VF.

Atropine has failed to improve a patient's symptomatic bradycardia. Appropriate next steps include:

• a.Pacing or an epinephrine drip✓
• b.Defibrillate the patient
• c.Adenosine 6 mg rapid IV push
• d.Synchronized cardioversion

If atropine is ineffective, the 2025 Guidelines call transcutaneous pacing or agents that raise heart rate and blood pressure (such as epinephrine or dopamine) reasonable; the choice depends on experience and resources.

For a patient with a STEMI, the goal for first-medical-contact-to-device time with primary PCI is within:

• a.30 minutes
• b.90 minutes✓
• c.4 hours
• d.12 hours

For STEMI, the reperfusion goal for primary percutaneous coronary intervention (PCI) is a first-medical-contact-to-device time of 90 minutes or less. 'Time is muscle' — the sooner the occluded coronary artery is reopened, the more myocardium is salvaged. When timely PCI is unavailable, fibrinolytic therapy is targeted within 30 minutes of arrival (door-to-needle).

Before a clot-dissolving drug is given for suspected acute ischemic stroke, what must brain imaging do?

• a.Show the carotid arteries
• b.Exclude bleeding in the brain✓
• c.Measure brain temperature
• d.Replace the neurologic exam

Brain scans show what type of stroke has occurred, and CT or MRI identifies bleeding; thrombolytic therapy is for strokes caused by a clot, so hemorrhage must be excluded first.

For an adult who remains unresponsive to commands after ROSC, what temperature control do the 2025 AHA Guidelines recommend?

• a.32–37.5 °C for at least 36 hours✓
• b.38–40 °C for 12 hours
• c.28–30 °C for 72 hours
• d.No temperature management

The 2025 Guidelines recommend maintaining a temperature between 32 °C and 37.5 °C in adults unresponsive to verbal commands after ROSC, and consider 36 hours of total temperature control the shortest recommended duration.

During an ACLS code, the feedback device shows a compression rate of 132 per minute. What should the team leader say?

• a.Slow down to 100–120✓
• b.Switch to breaths only
• c.Pause and restart at 140
• d.Keep going; faster is better

Adult compressions are delivered at 100 to 120 per minute; survival evidence favored rates in that range over faster ones, and faster compressions shorten refilling time.

A code has run 18 minutes with frequent long pauses for pulse checks. What metric is likely too low?

• a.Epinephrine dose
• b.Oxygen flow
• c.Compression fraction✓
• d.Pad size

The chest compression fraction is the share of time with compressions; pulse checks longer than 10 seconds reduce it, and 60% is the minimum target.

Why does the ACLS team leader watch compression quality even while ordering drugs?

• a.Drugs work only after compressions stop
• b.CPR is the most critical intervention✓
• c.Compressions matter only before the first shock
• d.The leader must do compressions personally

The Guidelines call high-quality CPR the single most critical intervention for a patient in cardiac arrest; drugs and airways support resuscitation but perfusion comes from compressions.

During CPR the ETCO2 is 9 mm Hg. What adjustment is most likely to help?

• a.Give sodium bicarbonate
• b.Increase ventilations to 30 per minute
• c.Stop CPR for a rhythm check
• d.Improve compression depth and rate✓

ETCO2 reflects cardiac output during CPR and rises with better compression depth; the Guidelines suggest targeting at least 10 and ideally 20 mm Hg. Faster ventilation risks harm and bicarbonate is not routine.

How often should compressors switch during a prolonged resuscitation?

• a.Every 30 seconds
• b.Only when exhausted
• c.About every 2 minutes✓
• d.Every 10 minutes

Depth falls after 90 to 120 seconds, so rotating the compressor about every 2 minutes, at the planned rhythm check, keeps quality up.

After a shock, a resident wants to check for a pulse before resuming CPR. What is the correct practice?

• a.Wait for the monitor to settle
• b.Give a second shock first
• c.Resume CPR immediately✓
• d.Check the pulse for 10 seconds

Immediate resumption of compressions after a shock shortens the perishock pause and improves hands-on time; rhythm and pulse are checked after 2 minutes.

A patient in arrest is on a soft ICU bed. What quickly improves compression depth?

• a.Mechanical CPR as routine
• b.Faster compressions on the soft bed
• c.Moving to a stretcher in the hallway
• d.The bed's CPR mode or a backboard✓

A firm surface improves depth; the Guidelines note that a backboard, a deflated dynamic mattress or the bed's CPR mode can improve compression depth in hospital.

What is the minimum chest compression fraction target during adult CPR?

• a.30%
• b.45%
• c.60%✓
• d.100%

A compression fraction of 60% is considered a minimum target, and high-performing teams may exceed 80%.

An intubated adult receives CPR. How are compressions and ventilations coordinated?

• a.15:2 cycles with pauses
• b.Continuous CPR; 10 breaths/min✓
• c.30:2 cycles with pauses
• d.Compressions pause for every breath

With an advanced airway, compressions continue without pausing for ventilations, which are given at about 10 per minute.

Why is excessive ventilation during ACLS harmful?

• a.It prevents ROSC entirely
• b.It causes VF
• c.It lowers ETCO2 to zero
• d.It reduces cardiac output✓

Excessive ventilation can cause gastric inflation, regurgitation, aspiration and decreased cardiac output; too little is also harmful.

Which statement reflects the 2025 position on mechanical CPR devices in hospitals?

• a.Not recommended for routine use✓
• b.Recommended for every in-hospital arrest
• c.Required once an airway is placed
• d.Proven to improve survival

Mechanical CPR has not been shown better than manual CPR for survival, so routine use is not recommended; it may be considered where manual CPR cannot be maintained.

A nurse asks whether a step stool is useful during CPR on a high bed. What does the 2025 guidance say?

• a.Only when using mechanical CPR
• b.Yes; knees level with the torso✓
• c.Only for pediatric patients
• d.No; rescuers should always stand

Rescuers should position themselves so that their knee is aligned with the patient's torso, by kneeling or using a step stool, to improve compression quality.

A paramedic intubates a patient in cardiac arrest a few minutes after collapse. Which finding best confirms the tube is in the trachea?

• a.Equal pupils
• b.Fogging inside the tube
• c.A capnography waveform✓
• d.The patient's color improving at once

Waveform capnography was 100% specific for confirming endotracheal tube position during cardiac arrest in the studies cited; tube fogging and color change are unreliable signs.

A team is choosing between a supraglottic airway and intubation during out-of-hospital arrest. What does the evidence show?

• a.No clear winner for survival✓
• b.Neither may be used during CPR
• c.Intubation always improves survival
• d.Supraglottic airways are harmful

Trials comparing supraglottic airways and intubation gave mixed results, and a systematic review found no clear survival benefit for either.

What should guide the choice of advanced airway during cardiac arrest?

• a.The patient's age alone
• b.Whatever the nearest device is
• c.Rescuer skill and setting✓
• d.The time since the last meal

The Guidelines stress that the use, type and timing of an advanced airway depend on patient and professional characteristics, especially airway skill and experience.

In VF arrest, when should an advanced airway be placed?

• a.Without delaying CPR and shocks✓
• b.Only after 30 minutes
• c.Before the first shock
• d.Before any compressions

In shockable rhythms, CPR and defibrillation must take priority, so an advanced airway is weighed against maintaining a high compression fraction.

What basic airway strategy does resuscitation usually start with?

• a.Bag-mask ventilation✓
• b.Supraglottic airway only
• c.Surgical airway
• d.Intubation before CPR

Airway management during cardiac arrest usually begins with bag-mask ventilation, with an advanced airway added according to skill and setting.

Minutes into a cardiac arrest, a newly placed endotracheal tube shows no capnography waveform. What is the most likely explanation?

• a.This is expected during CPR
• b.Compressions are too deep
• c.The tube may be misplaced✓
• d.ROSC has occurred

Waveform capnography is highly specific for confirming tube position; the absence of a waveform suggests the tube is not in the trachea, although sensitivity falls after prolonged arrest.