ACLS guidelines evolve — and with those changes come new standards that sometimes contradict what providers learned years ago. Whether you’re preparing for recertification or simply want to sharpen your resuscitation skills, these five clinical pearls cut through the confusion and give you clear, evidence-based answers to questions that come up in real codes.

1. Immediate CPR After Defibrillation — Even If the Patient Has Pulses?

Yes. And it’s not harmful.

After a successful defibrillation, a palpable pulse is unlikely to be present in the immediate moments that follow — even if the heart has restarted. When an organized rhythm returns, it takes time for the heart to build enough circulation to generate a pulse you can feel at a peripheral site. Pausing CPR to check for one wastes critical seconds.

Starting compressions immediately after shock delivery supports circulation if defibrillation failed, and boosts circulation during this vulnerable window if it succeeded. Studies suggest this approach actually increases the likelihood of sustained ROSC. The new guidelines aren’t arbitrary — they’re built on evidence that compressions in this moment help, not hurt.

Bottom line: Resume CPR immediately after every shock. Check the rhythm at the next scheduled pause.

2. Sodium Bicarbonate Is Not a Routine Cardiac Arrest Drug

Acidosis is common in cardiac arrest, but that doesn’t mean sodium bicarbonate belongs in every resuscitation.

The acidosis seen during cardiac arrest is typically respiratory acidosis — caused by inadequate ventilation, not a metabolic problem. The fix for respiratory acidosis is restoring ventilation, not buffering with bicarbonate. Giving sodium bicarbonate routinely does not improve outcomes and does not address the actual cause.

Sodium bicarbonate should be reserved for cases where metabolic acidosis is a suspected reversible cause of the arrest — such as tricyclic antidepressant overdose or severe hyperkalemia. In those specific scenarios, it’s appropriate. In a routine arrest, it’s not.

Bottom line: Treat the cause of the acidosis. Optimize ventilation first. Reserve sodium bicarbonate for specific indications.

3. Don’t Check for a Pulse After Defibrillating

This one surprises a lot of providers. Checking for a pulse after defibrillation feels instinctive — but the guidelines are clear: don’t do it.

The goal of defibrillation is to interrupt VF or pulseless VT and allow an organized rhythm to return. When that rhythm does return, the heart needs time to restore normal circulation before a pulse is palpable. Interrupting CPR to check for a pulse that isn’t there yet allows circulation to drop and risks pushing the patient back into arrhythmia.

Providing chest compressions immediately after the shock maintains perfusion pressure and protects the newly restarted heart during its most vulnerable moments.

Bottom line: After every shock, go straight back to compressions. No pulse check until the next 2-minute CPR cycle is complete.

4. Stacked Shocks Are No Longer Recommended

If you trained on the old “shock, shock, shock” protocol, this is one of the most important updates to internalize.

Evidence shows that defibrillation success is directly tied to minimizing the gap between the last chest compression and shock delivery — the pre-shock pause should be under 10 seconds. Stacked shocks, delivered back-to-back without CPR in between, significantly reduce the total amount of CPR the patient receives and are less likely to be successful than a single well-timed shock followed by immediate compressions.

One shock. Back to CPR. That’s the standard.

Bottom line: Deliver one shock, resume compressions immediately, and reassess at the next rhythm check. Stacked shocks are out.

5. Intraosseous Access Is Just as Effective as a Peripheral IV

IO access is not a backup plan — it’s a legitimate, guideline-supported route for resuscitation drugs.

Drug delivery through an intraosseous device is comparable to delivery through a peripheral IV. Medications are given at the same dose as IV, and IO access can be established rapidly when peripheral access is difficult or impossible during a cardiac arrest. There is no reason to delay resuscitation hunting for a vein when IO access is available.

One caveat: medications with an extremely short half-life — such as Adenosine — may be less effective depending on where the IO is placed, due to slower transit to central circulation. For those specific drugs, a more proximal site or alternative access is preferable when possible.

Bottom line: Don’t hesitate to use IO. It’s fast, reliable, and guideline-approved at the same dose as IV.

Stay Sharp. Stay Current.

ACLS guidelines exist because the evidence keeps improving — and so should your practice. These five pearls represent some of the most commonly misunderstood points in resuscitation, and knowing them cold can make a real difference in a code.

Ready to recertify or brush up on the full scope of ACLS? Explore ACI’s 100% online ACLS courses — built on the most current ILCOR/AHA/ECC guidelines and available on your schedule.

Author: Timothy Fitzgerald, MD | Reviewer: ACI Medical Team | Published: July 1, 2026 | Last Updated: July 1, 2026