New CPR guidelines: What changed?
Post-cardiac arrest oxygen and CO2 targets, seizure prophylaxis, more
New guidelines on cardiopulmonary resuscitation in adults were published in Circulation in November 2024. They’re 187 pages long.
What’s changed, and what do you need to know?
Who Writes the CPR Guidelines?
The International Liaison Committee on Resuscitation (ILCOR) is comprised of experts on resuscitation around the world. ILCOR is a scientific advisory body to the American Heart Association and similar societies in other countries. The committee convenes and issues recommendations periodically; the American Heart Association (AHA) generally then incorporates ILCOR’s recommendations into its published guidelines, which set the standard of care for cardiac arrest and resuscitation in the U.S.
How Evidence-Based Are the CPR Guidelines?
Most of the CPR guidelines are based on a very low-quality body of evidence (retrospective observational studies, simulation-based studies, etc). Although millions of cardiac arrests happen each year globally, high-quality clinical research on resuscitation is very difficult to conduct, due in part to challenges in obtaining consent and randomization.
Unless otherwise noted, the CPR guidelines referenced here are ILCOR’s weak recommendations based on low-certainty evidence.
“Cardiac Arrest Centers” Upvoted
After out-of-hospital cardiac arrest (OHCA), the committee recommended patients be treated at a “cardiac arrest center”—by which they mean a hospital that describes itself as a “critical care medical center”, “tertiary heart center,” or “regional center” and offers at least two of the following menu of services:
24/7 heart catheterization
Mechanical ventilation
Targeted temperature control
Neurology consultations
Extracorporeal membrane oxygenation (ECMO)
In several observational trials, patients treated after OHCA at cardiac arrest centers had better outcomes, although the likelihood of confounding should be obvious (as these are larger, better-resourced hospitals generally):

Backboards
There was no strong endorsement of backboards to provide a firm surface to enhance chest compression quality.
Treating teams were encouraged to place patients on firm surfaces only if it would not delay the initiation of CPR.
If a bed has a CPR mode (which stiffens the bed surface), it was suggested that someone push the button to activate the mode.
Hospitals not using backboards were not encouraged to start.
These suggestions came from studies testing CPR on manikins, not live patients.
Feedback Devices for CPR Quality
Low-quality evidence suggests that audiovisual feedback devices (“PRESS HARDER”, etc.) can improve the depth and rate of chest compressions. Very few studies testing these devices were randomized, and nearly all tested them as part of a more comprehensive quality improvement program, limiting conclusions about feedback devices per se.
Audiovisual feedback devices continue to be weakly recommended to improve CPR quality, but only as part of a comprehensive quality improvement program.
Oxygen and CO2 Targets After Cardiac Arrest
Delivery of 100% oxygen is advised after cardiac arrest in any setting until the patient has reliable pulse oximetry. Both hypoxemia and hyperoxemia are to be avoided.
A specific target of oxygen saturation of 94% to 98% or partial pressure of arterial oxygen of 75 to 100 mm Hg was recommended. This was new. There was no new evidence for this—the committee just wanted to be more specific than previously to eliminate any confusion.
They also suggested targeting a normal partial pressure of carbon dioxide (35–45 mm Hg) after ROSC has been achieved post-cardiac arrest.
Blood Pressure Targets Post-Cardiac Arrest
There was insufficient evidence to recommend a specific blood pressure target after ROSC is achieved post-cardiac arrest.
Therefore, the committee advised a default target of a mean arterial pressure of at least 60 to 65 mm Hg after cardiac arrest in any setting.
Temperature Targets After Cardiac Arrest: <37.5° = OK
In 2022, ILCOR and the AHA acknowledged the lack of evidence supporting hypothermia after cardiac arrest: the original studies were never convincingly replicated, and the largest randomized trials suggested no benefits from cooling patients below 37.5° Celsius.
Interim guidance at that time made cooling optional, but advised active temperature management to prevent fevers:
This guideline update reaffirms that position.
They also walked back the previous suggestion for the duration of active fever prevention in patients who remain comatose, from 72 hours to “36 to 72 hours.” This was new.
Seizure Prophylaxis and Treatment of Abnormal EEGs
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