BLS simplified algorithm
Last updated: September 11, 2023
Version control: Our ACLS, PALS & BLS courses follow 2020 American Heart Association
Guidelines for CPR and ECC. American Heart Association guidelines are updated every five years. If you are
reading this page after December 2025, please contact support@ACLS.net for an update. Version 2021.01.c
For laypersons or other non-health care personel (HCP)
The simplified ADULT BASIC LIFE SUPPORT algorithm includes five steps. The algorithm diagram provided by the
American Heart Association emphasizes the following:
-
Assess the victim's responsiveness. If a victim is not breathing, or is not breathing normally
(i.e., gasping), initiate CPR. Health care professionals should be trained to recognize cardiac arrest that
presents as seizure-like activity or with agonal respirations.
- Activate EMS (Emergency Medical Response) by calling 911.
- Retrieve a defibrillator, usually an automatic external defibrillator (AED).
- The algorithm proceeds in a loop of CPR and rhythm checks with defibrillation.
-
Check PULSE before chest compressions for at least five seconds and no more than ten seconds. If
in doubt, begin compressions.
-
If there is a pulse but inadequate or absent breathing give 10 BREATHS a minute, or one breath every six seconds. Each breath should be delivered over 1 second. For effective breathing, watch for chest rise and avoid excessive ventilation. Avoid gastric inflation, as it may result in aspiration, pneumonia, or vomiting.
-
CPR: push hard and fast. Begin chest compressions before ventilation. Chest compressions allow
blood flow to the heart and brain. Delays in chest compressions result in diminished survival. Be sure to allow
the chest to recoil between compressions. The chest should be compressed 100–120/min to a depth of 2–2.4” (5–6cm)
- The ratio of chest compressions to breaths is 30 to 2.
-
After the defibrillator becomes available,
check rhythm. USE THE AED WHEN INDICATED AND AVAILABLE. The victim should receive a shock that is repeated
every two minutes or 5 cycles.
BLS algorithm feedback and questions
I'm a certified ACLS provider by AHA, currently working as a ship's doctor on a german ship. My German colleagues
assert that it is no longer necessary to check pulse before starting the chest compressions, and it is recommended
only to check responsiveness and breathing. Could you let me know about it please?
The AHA Guidelines uses the “absence of normal breathing” as indication for chest compressions when teaching lay
rescuers. In the health professional certification, healthcare providers are taught to first check for presence or
absence of normal breathing, then to check a pulse. No more than ten seconds should be taken to do this and if there
is any doubt of the existence of a pulse, compressions should be started. There is no harm in doing compressions if
a pulse is present, but delaying them when a pulse is not present ensures poor outcome. I hope this answers helps to
clarify the guidelines for you.