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ACLS Algorithms 2023 (Advanced Cardiac Life Support)

Introduction: What is Advanced Cardiac Life Support (ACLS)?

ACLS is an acronym that stands for Advanced Cardiac Life support. ACLS teaches healthcare professionals advanced interventional protocols and algorithms for the treatment of cardiopulmonary emergencies. These include primary survey, secondary survey, advanced airways, myocardial infarction, cardiac arrest, tachycardias, bradycardias, and stroke. The treatment protocols have been established through collaborative clinical research and later published by the International Liaison Committee on Resuscitation (ILCOR).

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Welcome to our ACLS algorithms and guidelines page offered free here at United Medical Education. Take your time to review each section. Here you’ll find everything you’ll need to prepare for ACLS certification. We have a separate page for additional information on the anatomy of the human heart.

Secondary ABCD (Airway, Breathing, Circulation, Differential Diagnosis)

Airway (two provider)


If the patient is not ventilating well or if there is a presumed risk of aspiration, insert an advanced airway device when prudent:
Endotreacheal Intubation is the preferred method.
(View the advanced airway section)


Confirm correct placement of the advanced airway device:

If incorrect placement:

If correct placement:

Continue to monitor:

Rescue breathing during CPR with an advanced airway:



Differential Diagnosis

(needed for successful treatment of some patients)
Consider reversible causes of rhythm/arrhythmia.

Differential Diagnosis Chart:


Airway & Breathing

There are two important principles when evaluating the airway and breathing. First, is the airway patent or obstructed. Second, is there possible injury or trauma that would change the providers method of treating an obstructed airway or inefficient breathing.

If the airway is patent there should be noticeable chest rise/expansion with either spontaneous respirations or with rescue breaths. The provider may also be able to hear or feel the movement of air from the patient.
A completely obstructed airway will be silent. An awake patient will lose their ability to speak, while both a conscious or unconscious patient will not have breath sounds on evaluation. If the patient is attempting spontaneous breaths without success, there may be noticeable effort of intercostal muscles, diaphram, or other accessory muscles without significant chest rise/expansion. The provider will also not feel or hear the movement of air. If the airway is partially obstructed snoring or stridor may be heard.

Cervical Spine Injury?
If the provider evaluates the patient to have an obstructed airway, intervention should take place. If the adverse event of the patient was witnessed and there is no reason to suspect a cercival spine injury, the provider should use the head tilt-chin lift maneuver to open the airway.
If there is a reason to suspect a cervical spine injury, if the patient’s adverse event went unwitnessed, if trauma occured, or the patient suffered drowning the jaw-thrust maneuver should be used to open the airway. If the jaw-thrust proves unsuccessful in opening the patient’s airway attempt an oropharangeal or nasopharangeal airway. If neither technique works, attempt an advanced airway using inline stabilization.

Brain Injury?
The breathing center that controls respirations is found within the pons and medulla of the brain stem. If trauma, hypoxia, stroke, or any other form of injury affects this area, changes in respiratory function may occur. Some possible changes are apnea (cessation of breathing), irregular breathing patterns, or poor inspiratory volumes. If the breathing pattern or inspiratory volumes are inadequate to sustain life, rescue breathing will be required, and an advanced airway should be placed.

Oral Airway:

Nasal Trumpet Airway:

Advanced Airways


Remember, a patient should be unconscious or sedated without an active gag reflex before instrumentation of the airway occurs with an ETT, Combitube, or LMA.

Endotracheal Tube (ETT)

Average depth of intubation:

endotracheal tube

Esophageal-Tracheal Combitube

First attempt confirmation of esophageal intubation by ventilating through the esophageal tube. (See “Secondary ABCD” section regarding placement confirmation)

If placement not confirmed through esophageal tube:

Once placement has been confirmed:

Laryngeal Mask Airway (LMA)

Visualization of the vocal cords is not required for insertion.

Positive pressure ventilation is generally kept under 20 CmH2O to prevent inflation of the stomach. LMA’s are contraindicated for the morbidly obese patient.

The patient is still at high risk of aspiration, even with an appropriately placed LMA. LMA’s are contraindicated in patients with GERD, full stomachs, and pregnant women.

Cardiac/Electrical Therapy

Transcutaneous Pacemaker (External Pacemaker):
Used to treat unstable bradycardias not responding to drug therapy. Provides temporary pacing through the skin in emergency situations.


Shock energy level:
Monophasic: 100-200J
Biphasic: factory recommendations (generally 100J)
Assure the patient is sedated and comfortable during shock delivery.


Shock energy level:
Monophasic: 360J
Biphasic: factory recommendations (generally 120-200J)


Common Cardiac Rhythms

Normal Sinus Rhythm


Atrial Tachycardia


Supraventricular Tachycardia


Atrial Fibrillation


Atrial Flutter


Sinus Bradycardia


1° Atrioventricular Block


2° Atrioventricular Block- Type 1 (Mobitz I/Wenckebach)


2° Atrioventricular Block- Type 2 (Mobitz II/Hay)


3° Atrioventricular Block (Complete Heart Block)


Ventricular Tachycardia – Monomorphic


Ventricular Tachycardia – Polymorphic


Ventricular Tachycardia – Torsades de Pointes


Ventricular Fibrillation




Pulseless Electrical Activity (PEA)


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Acute Myocardial Infarction

ACLS Adult Cardiac Arrest Algorithm


Narrow QRS Complex – Stable



Narrow QRS Complex – Unstable

Wide Complex – Stable


Ventricular Tachycardia (monomorphic):

SupraVentricular Tachycardia (SVT) with Aberrancy:


Atrial Fibrillation with Aberrancy:

Atrial Fibrillation with Wolff Parkinson White (delta wave):

Toursades de Pointes:

Wide Complex – Unstable

Ventricular Tachycardia (VT) – monomorphic:

Ventricular Tachycardia (VT) – polymorphic:

Pulseless Ventricular Tachycardia / Ventricular Fibrillation (Refractory):


Using defibrillator:

Drug treatment options:

Treat the cause of the arrhythmia.

Bradycardia (Rate < 60)




Drug therapy:

Pulseless Electrical Activity​

Drug Therapy:

Acute Stroke

Initiated treatment within 10 min of arrival to the ER:

Initiated treatment within 25 min of arrival to the ER:

ACLS Case Scenarios

1) You are shopping at a grocery store and an elderly lady in the produce section suddenly grimaces, grabs her chest, and falls to the floor. You and a few others hurry to her side and she quickly becomes unresponsive.

Appropriate Action:

[Patient is not breathing.]

[Patient has no pulse.]

[Have the student explain the steps of 2 person CPR.]
[Onlooker arrives with the AED.]

[Have the student explain the correct use of the AED.]
[After the AED analyzes the patient a shock is recommended.]

2) You are just returning from lunch to the ER and you hear a code blue being initiated in bay 2. You run to the bay to find a patient confused, obtunded, and lethargic in the bed. Oxygen by NC, ECG, and IV access are already established. The nurse is unable to cycle a blood pressure. When assessing the ECG you see:


What should you do next?

[Patient is breathing.]
[Faint pulse is felt approximately 35 times a minute.]

[Central line access is established.]

3) You enter your friends house to find their elderly grandmother staring at the wall and leaning to their side.

[Have student identify signs of stroke.]
[Have student perform prehospital stroke assessment.]

[Have student explain appropriate medical interventions for this patient.]


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