Advanced Cardiac Life Support (ACLS) Overview: What You Need to Know

If you work in the medical field, then you have probably heard of ACLS. But what exactly is it?

Advanced Cardiac Life Support (ACLS) is a set of guidelines that healthcare providers use to treat cardiac arrest and other life-threatening cardiovascular emergencies.

In this blog post, we will provide an overview of what you need to know about ACLS. We will discuss the history of ACLS, the goals of the program, and the basic steps involved in providing treatment.

Disclaimer: The information covered in this post is in line with the 2020 American Heart Association ACLS guidelines.

ACLS History and Goals

ACLS was created in the 1970s in response to the growing number of cardiac arrests that were occurring outside of the hospital setting.

The goal of ACLS is to improve patient outcomes by providing high-quality care in a timely manner.

One of the key ways that ACLS achieves this goal is by standardizing the care that is provided.

The ACLS guidelines are based on the latest evidence and best practices.

They are regularly updated to ensure that healthcare providers are using the most effective treatments.

To learn more about Basic Life Support (BLS)? ^^^ Click the Title above ^^^

Adult BLS Assessment

The basic steps of BLS are:

  • Verify scene safety
  • Check for responsiveness
  • Call for help (Activate the Emergency Response System)
  • Check for breathing and pulse
  • Begin chest compressions
  • Provide rescue breaths
  • Continue chest compressions and rescue breaths until help arrives or the patient begins to breathe on their own

Verify scene safety

Many times you may find that the scene may be unsafe with locations such as in the water, in the middle of the road, etc. If it is not safe, make the scene safe and move the person prior to starting interventions.

Check for Responsiveness

Tap the shoulders and shout “Are you okay?”

If the patient does not respond, then they are unresponsive.

Activating the Emergency Response System

The first step in any emergency is to call for help.

You have two options

  • If you have someone near you, have them get help and obtain an AED/Defibrillator
  • If you are by yourself, perform a round of CPR then call for help and obtain an AED/Defibillator

Checking for Breathing and a Pulse

To check for breathing, look for the rise and fall of the chest.

To check for a pulse, place your fingers on the inside of the patient’s neck, just below the angle of the jaw. You will palpate the carotid pulse.

These actions should be performed a maximum of no more than 10 seconds.

If no breathing and pulse are present, immediately begin cardiopulmonary resuscitation (CPR).

Compressions, Airway, Breathing (CAB)

Chest Compressions Ratios and Placement

For adults, the compression-to-ventilation ratio is 30:2 (30 compressions followed by two breaths).

Begin by placing the palm of your hand over the patient’s sternum just above the xiphoid process. Previous indicator was to place the palm of your hands on the mid-nipple line; however, due to the increase in obesity the nipple line may no longer be the best indicator.

Disclaimer regarding rescue breaths: According to guidelines posted by the American Heart Association on January 24, 2022, appropriate percautions should be worn when providing BLS, ACLS, and PALS standards with potential and confirmed COVID-19 positive patients. All providers should wear a respirator (i.e. N95), gown, gloves, and eye protection for suspected or confirmed COVID-19 infections, when performing aerosol-generating procedures (AGP)s. Out of hospitla cardiac arrest is dependent on early initiation of CPR including chest compression. It is not recommend for mouth to mouth resuscitation at this time but all patients should receive the best resuscitative efforts.

Depth of Chest Compressions

For adults, the depth of chest compressions should be at least two inches (five centimeters).

Chest Compression Rate

The compression rate should be 100-120 compressions per minute.

You can keep track of the rate by counting out loud or using a metronome.

Allow for full chest recoil between compression and minimize interruptions to less than 10 seconds.

Be sure to switch compression team members every 2 minutes.

Airway and Breathing (CAB)

Utilize the head tilt-chin lift or jaw thrust (trauma to the cervical spine).

Rescue breaths are one breath every 5 to 6 seconds. You will want to see visible chest rise and fall within each rescue breath.

It is important to avoid excess ventilation because it can decrease coronary perfusion pressure and a reduction of cerebral blood flow causing PaCO2 to decrease.

How to use an AED/Defibrillator

When the AED arrives, review the instructions with the bystander.

If you are alone, perform one minute of CPR before using the AED.

Step One: Turn on the AED and follow the prompts.

Step Two: After removing the person’s shirt, apply the electrode pads to the patient’s bare chest in accordance with the instructions and plug in the connector. It is important to remove any wet barriers or medication patches before applying the pads.

Step Three: Stop chest compressions and confirm everyone is clear by saying “Stand Clear.”

Step Four: Push the analyze button and the AED will analyze the patient’s heart rhythm and, if needed, deliver a shock.

Step Five: if a shock is recommended, make sure no one is touching the person and repeat “Stand Clear.” Once clear, press the shock button.

Step Six: Immediately begin CPR following the shock or if no shock is advised. Perform another two minutes of CPR and follow the AED prompts again.

Bradycardic Rhythms in ACLS

Some bradycardic rhythms you may encounter in ALCS include sinus bradycardia, first-degree heart block, second-degree heart block type I, second-degree heart block type II, and third-degree heart block.

Sinus Bradycardia is defined as a heart rate of less than 60 bpm and the QRS complex is normal. The patient may or may not have symptoms.

First-degree heart block is defined as a PR interval greater than 0.20 seconds but less than 0.30 seconds with a normal QRS complex. The patient usually has no symptoms.

Second-degree heart block type I is defined as a PR interval greater than 0.20 seconds with some occasional dropped QRS complexes.

Second-degree heart block type II is defined as a constant PR interval greater than 0.20 seconds with consistently dropped QRS complexes.

Third-degree heart block is defined as a complete absence of electrical conduction from the atria to the ventricles. The atrial rhythm is regular and the QRS complex is regular with a rate of less than 60 bpm. The conduction in the atria is not communicating with the conduction system in the ventricles.

Bradycardic Rhythm Interventions


If symptomatic, the ACLS guideline’s first drug of choice recommends atropine for bradycardia interventions. The initial dose is 1 mg (maximum of 3 mg) and may be given every three to five minutes.

Second-degree type II and third-degree heart blocks do not typically respond to atropine.

If the patient is unresponsive to atropine or has a high-degree heart block, you will need to place transcutaneous pacing pads.

Transcutaneous Pacing

Transcutaneous pacing is an external form of pacing that uses electrical current to stimulate the heart through the skin. This is considered a temporizing measure and is not a definitive treatment.

The pads are placed in the anterolateral position on the patient’s chest and plugin the pacing unit.

The unit will automatically deliver a pacing stimulus/demand rate at 60-100 bpm.

Pacer current (mA) output is also important as it determines the strength of the electrical impulse being delivered to the heart. The higher the number, the greater current being delivered which can cause burns if used for too long.

The recommended settings for an adult are:

-Pacing mode: demand

-Pacing rate: 60-100 bpm (can be set lower if the patient has a pre-existing tachycardia)

-Pacer output: 50-80 mA

Transcutaneous pacing should be continued until the patient’s condition improves, a transvenous pacemaker can be placed, or for no more than 45 minutes to avoid skin burns and patient discomfort.

Transcutaneous Precautions

Conscious paced patients may require additional analgesics for pacing discomfort. Also, you will want to avoid palpating the carotid pulses to confirm capture as the electric impulses cause muscle jerking that may mimic a pulse.


Dopamine is the second drug of choice for symptomatic bradycardia. The starting dose is low at 5 to 20 mcg/kg/min and should be titrated slowly based on the patient’s blood pressure/hemodynamics.

It is important to correct any hypovolemia with adequate fluid replacement prior to starting any dopamine drip. Use this medication cautiously with cardiogenic shock with congestive heart failure.

For additional precautions, please reference an up-to-date drug guide.


Epinephrine is an alternative drug choice for symptomatic bradycardia in place of dopamine when not appropriate. This alternative is usually used when pacing and atropine fail as well as in cases of severe hypotension.

The recommended dose is 2 to 10 mcg/min infusion and should be titrated slowly based on the patient’s blood pressure/hemodynamics.

Use epinephrine cautiously as raising blood pressures with an increase in heart rate can cause angina, myocardial ischemia, and increase oxygen demand.

For additional precautions, please reference an up-to-date drug guide.

Tachycardic Rhythms in ACLS

One of the most common tachycardic rhythms you may encounter in ALCS includes supraventricular tachycardia.

Supraventricular Tachycardia is defined as tachycardia that originates from above the ventricles in the atria or AV node.

Tachycardic Rhythm Interventions

Oxygenation and Ventilation

The first and most important intervention for any patient in tachycardia is to ensure they are adequately oxygenated and ventilated.

As the oxygen demand on the heart increases with tachycardia, it is important to ensure they are receiving as much oxygen as possible.

Be sure to monitor the patient’s oxygen saturation for any changes in condition or fluctuation that may require supplemental oxygen.

Vagal Maneuvers

Vagal maneuvers are a physical intervention used to decrease the heart rate by stimulating the vagus nerve.

The most common maneuver is the Valsalva maneuver which is performed by having the patient:

  • Take a deep breath in
  • Attempt to exhale by bearing down or blowing through an occluded 10mL syringe for 15 to 20 seconds

This should result in a decrease in heart rate by decreasing the conduction of electrical impulses through the AV node.

Additional vagal techniques include coughing, a cold stimulus to the face, carotid massage, and gagging.


If unsuccessful vagal maneuvers are unsuccessful, the next step is to administer adenosine.

Adenosine is a medication that works by decreasing the conduction of electrical impulses through the AV node.

The recommended initial dose is 6 mg given as a rapid IV push followed by a 20 mL saline flush. It also helps to elevate the extremity after administration.

The recommended second dose is 12 mg given as a rapid IV push followed by a 20 mL saline flush. Typically, you will wait for 1 to 2 minutes between doses as needed.

Synchronized Cardioversion

If the patient remains unstable or unresponsive to previous interventions, synchronized cardioversion may be necessary.

Cardioversion is a procedure that uses electrical shocks to reset the heart’s electrical impulses and rhythm.

It is important to note that this should only be done when the patient is unstable or unresponsive as it can be a painful and traumatic experience for the patient.

The recommended dose of electricity is 50-100 J for monophasic defibrillators and 100- J for biphasic defibrillators. However, always follow your facility’s guidelines for the most accurate doses.

Initial recommended voltage doses

  • Narrow regular (SVT): 50 – 100 joules (SVT or Atrial Flutter)
  • Narrow irregular: 120 – 200 joules biphasic or 200 joules monophasic (atrial fibrillation)
  • Wide regular: 100 -360 joules (monomorphic ventricular tachycardia)
  • Wide irregular: defibrillation dose (not synchronized cardioversion)

Synchronized Cardioversion Procedure

  1. Obtain a 12-Lead ECG if the patient is stable
  2. Prepare proper sedation since cardioversion is painful and have emergency equipment ready in case of complications
  3. Place defibrillator pads on the patient and set the monitor to synchronized (sync) mode. Engage the synch mode before each attempt.
  4. Look for sync markers above each R wave.
  5. Set your dose of electricity/voltage
  6. Clear all personnel from the patient prior to the shock
  7. Press the “charge” button, “clear” the patient, and press the “shock” button
  8. Reassess the patient after each shock

ACLS Shockable Rhythms

There are two shockable rhythms in the AHA ACLS guidelines that you may encounter in ACLS: pulseless ventricular tachycardia and ventricular fibrillation.

Pulseless Ventricular Tachycardia is defined as a wide complex tachycardia with a heart rate of >100 bpm in the absence of a pulse.

Ventricular Fibrillation is defined as a rapid, erratic, and chaotic electrical activity in the ventricles that results in the loss of coordinated contractions.

ACLS Shockable Rhythm Interventions

Cardiopulmonary Resuscitation

Cardiopulmonary Resuscitation (CPR) is the first line of defense for both of these rhythms as it provides oxygen to the heart and brain.

Review the Basic Life Support Guidelines for CPR detail


Defibrillation is the use of electrical shocks to reset the heart’s electrical impulses and rhythm without syncing to the patient’s intrinsic rhythm.

The recommended dose of electricity is 120-200 J for biphasic machines and up to 360 J for monophasic.

Defibrillation Procedure

  1. Turn on the defibrillator and set the joules based on the machine used
  2. Place adhesive pads on patient: one on the right anterior chest wall and one on the left axillary position
  3. Announce to the team “Charging defibrillator” and press the charge button
  4. When the defibrillator is fully charged, verify all team members are clear by announcing the shock. Once the team announces all clear and you have verified the team is not touching the patient or bed, call “All Clear!”
  5. Press the shock button on the defibrillator
  6. Immediately after shock is delivered, resume CPR for 5 cycles (2 minutes) then reassess rhythm


Epinephrine is a medication that is used to stimulate the heart and increase blood pressure.

The recommended dose is 1 mg administered every 3 to 5 minutes during resuscitation. Follow each dose with a 20 mL flush and elevate the arm for 10 to 20 seconds.


Amiodarone is a medication that is used to slow the heart rate and improve cardiac output.

The recommended initial dose is 300 mg IV or IO push.

The second dose is 150 mg IV or IO push.

The maximum dosage for amiodarone is 450 mg IV over 24 hours.


Lidocaine is a medication that is used to treat ventricular arrhythmias and is considered immediately after the return of spontaneous circulation (ROSC).

The recommended initial dose during active CPR is 1 to 1.5 mg/kg IV or IO.

Refractory Ventricular Fibrillation doses can be provided. This dose is 0.5 to 0.75 mg/kg IV push every 5 to 10 minutes (maximum 3 doses or total of 3 mg/kg).

Lidocaine can also be used for maintenance post-cardiac arrest is 1 to 4 mg/min (30 to 50 mcg/kg/min).

ACLS Non-Shockable Rhythms

There are two non-shockable rhythms in the AHA ACLS guidelines that you may encounter in ACLS: asystole and pulseless electrical activity.

Asystole is defined as a heart rhythm that is not amenable to defibrillation also known as a flat line.

Pulseless Electrical Activity (PEA) is defined as electrical activity on the monitor but no mechanical activity.

ACLS Non-Shockable Rhythm Interventions

Cardiopulmonary Resuscitation

Cardiopulmonary Resuscitation (CPR) is the first line of defense for both of these rhythms as it provides oxygen to the heart and brain.

Review the Basic Life Support Guidelines for CPR detail.


Epinephrine is a medication that is used to stimulate the heart and increase blood pressure.

The recommended dose is 1 mg administered every 3 to 5 minutes during resuscitation. Follow each dose with a 20 mL flush and elevate the arm for 10 to 20 seconds.

Consider your H and T causes

It is important to consider your H’s and T’s for these rhythms and treat accordingly.

H’s and T’s are mnemonics for the major causes of arrest:

  • Hypovolemia
  • Hypoxia
  • Hydrogen ions (acidosis)
  • Hyperkalemia or hypokalemia
  • Hypothermia
  • Tamponade (cardiac, tension)
  • Toxins
  • Tension pneumothorax
  • Thrombosis (coronary, pulmonary)

ACLS Post Cardiac Arrest / Return of Spontaneous Circulation (ROSC)

Once the patient has been successfully resuscitated, it is important to focus on post-arrest care.

This includes:

Brain Management

  • Targeted Temperature Management is the current standard of care for comatose post-cardiac arrest patients.
  • The AHA recommends a target temperature of 33 degrees Celsius for 24 hours be used in comatose patients.

Heart Management

  • Coronary intervention should be considered in all patients who remain unstable after resuscitation.
  • This can be done via angioplasty or thrombectomy.
  • Treat hypotension with systolic blood pressure less than 90 mmHg.
  • Obtain a 12-Lead ECG

Intensive Care Management

  • Respiratory Failure – Maintaining the patient’s airway, mechanical ventilation
  • Liver Failure – Monitor for signs and symptoms, maintain adequate nutrition
  • Renal Failure – Monitor for signs and symptoms, maintain hydration, dialysis if needed

AHA ACLS Acute Coronary Syndrome (ACS)

The AHA released updated guidelines for the management of ACS in 2020.

Acute Coronary Syndrome (ACS) is defined as a sudden onset of coronary artery disease that can lead to myocardial infarction (heart attack).

The mainstay of therapy for ACS is:

  • Obtain a 12-Lead ECG
  • Provide oxygen if oxygen is less than 94%
  • Aspirin 160-325 mg if no contraindications
  • Pain Control (morphine)
  • Nitroglycrin sublingual or spray

Obtain a 12-Lead ECG

The AHA recommends that all patients with ACS receive a 12-Lead ECG to assess for ST-segment elevation.

If the patient has ST-segment elevation, they should be treated with early reperfusion therapy.


The first and most important intervention for any patient in tachycardia is to ensure they are adequately oxygenated and ventilated.

As the oxygen demand on the heart increases, it is important to ensure they are receiving as much oxygen as possible.


The AHA recommends that all patients with ACS be treated with aspirin 162 to 325 mg as soon as possible.

There are very few contraindications to aspirin and it has been shown to decrease mortality in ACS.

Morphine Pain Control

Morphine is the preferred pain control agent in ACS.

It has been shown to decrease mortality and myocardial oxygen demand.


Nitroglycerin is a medication that is used to decrease the workload on the heart and coronary dilation.

It can be given sublingually or as a spray. The AHA recommends that all patients with ACS be treated with nitroglycerin.

Contraindications for nitroglycerin inclde right ventircular acute myocardial infarction and sexual enhancement medication use such as Cialis and Viagra.

STEMI (ST Elevation MI) Interventions

The AHA recommends early reperfusion for all patients with ST-segment elevation myocardial infarction.

Reperfusion can be done via thrombolytics or primary percutaneous coronary intervention.

  • Door to ballon inflation (PCI) goal is 90 minutes
  • Door to needle (fibrinloysis) goal is 30 minutes

ACLS Dynamic Teams

ACLS is a team-based approach to resuscitation.

The most important part of ACLS is the development of a well-functioning team that can work together to provide the best care for the patient.

The AHA recommends that all ACLS teams have a designated team leader.

The team leader is responsible for coordinating the efforts of the team and ensuring that all members are aware of their roles.

The AHA also recommends that all ACLS teams have a designated medical director.

The medical director is responsible for the overall medical care of the patient and for the development of ACLS protocols.

If a person is given an assignment outside of their scope of practice or are not knowledge, it is the person’s responsibility to ask for another role.

Lastly, closed loop communication is vitally important during resuscitation efforts. The person performing an action should repeat back what the person has called and advised for clarification or when an action is being performed.

ACLS Stroke Guidelines

The AHA released updated guidelines for the management of stroke in 2020.

The mainstay of therapy for stroke is:

  • Rapid identification and assessment
  • Determining the time of last known well (LKW)
  • Immediate blood pressure control if systolic blood pressure is greater than 185 mmHg or diastolic blood pressure is greater than 110 mmHg
  • CT scan with no contrast to be performed immediately upon arrival
  • Provide fibrinolytic therapy immediately as long as no contraindications are noted
  • Rapid transfer to a comprehensive stroke center if one is available
  • The AHA also recommends the use of telemedicine for the evaluation of stroke patients when a comprehensive stroke center is not available.

ACLS Mega Code Survey

The ACLS mega code survey is a tool that can be used to assess the knowledge of ACLS providers.

The ACLS Megacode survey consist of a primary survey and secondary survey.

ACLS Primary Survey (ABCDE)

The ACLS Primary Survey is ABCDE (Airway, Breathing, Circulation, Disability, and Exposure).


The airway should be assessed for patency and the presence of foreign bodies.

  • Maintain airway patency in unconscious patients​
  • Use advanced airway if needed​
  • Confirm CPR/Ventilation/Secure Device​
  • Monitor Airway Placement with continuous quantitative waveform capnography


The breathing should be assessed for the quality of breathing

  • Give supplementary oxygen as needed​
  • 100% oxygen for cardiac arrest patients​
  • Titrate oxygen for stable patients​
  • Avoid excessive ventilations​


The circulation should be assessed for blood pressure, heart rate, and pulse quality.

Monitor CPR quality

  • Minimize interruptions and checking pulse no more than 10 seconds
  • If person performing CPR starts to provide ineffective chest compressions: Give constructive feedback

Attach Monitor/Defibrillator/AED

  • First Step to using AED is turning on the device. Then follow the prompts. 

Obtain IV/IO Access

  • Give Appropriate medications
  • Administer IV/IO fluids

Check glucose levels/temperature/ capillary refill



The disability should be assessed for the level of consciousness and the presence of seizures.

  • Check for neurological function
  • Quickly assess for responsiveness (LOC, Pupil Dilation)


  • Alert
  • Verbal stimulation
  • Painful stimulation
  • Unresponsive


The exposure should be assessed for the presence of signs and symptoms of injuries.

Remove clothing: Assess for obvious signs of trauma, bleeding, burns, markings, medical alert bracelet.

ACLS Secondary Survey (SAMPLE)

The ACLS Secondary Survey is SAMPLE (signs and symptoms; allergies; medications, past medical history; last meal, liquid consumed; and events).

Signs and Symptoms

The signs and symptoms should be assessed for the presence of any changes.

  • Objective information from what we see
  • Subjective information from family or the ambulance


The allergies should be assessed for any food, medication, or environmental causes.


The medications should be assessed any medication causes.

  • Over the counter medications​
  • Vitamins​
  • Supplements​
  • Prescribed Medications​
  • Any medications not prescribed that may have been ingested or used

Past Medical History

The past medical history should be assessed pre-existing conditions.

  • Medical conditions​
  • Surgical history​
  • Previous hospitalizations
  • Clinical procedures​

Last Meal, Liquid Consumed

The last meal, liquid consumed should be assessed for the time of the last meal or drink.

  • Time of last meal​
  • Type of food or drink consumed


The events should be assessed for any changes that lead up to the current presentation.

  • Headache​
  • Dizziness​
  • Nausea/vomiting​
  • Visual changes​
  • Sudden onset of symptoms (e.g., slurred speech)


ACLS algorithms are standardized protocols that guide the management of a variety of cardiac and non-cardiac emergencies. These ACLS algorithms provide a framework for the delivery of care, but they do not replace the need for clinical judgment. The ACLS provider must be able to assess the patient, identify the problem, and select the appropriate ACLS intervention.

The ACLS provider must also be familiar with the basic concepts of advanced airway management, defibrillation, and intravenous access. These ACLS interventions are the cornerstone of care for cardiac and non-cardiac emergencies.

Jennifer Cheung


Meet Jennifer Cheung, a passionate nurse, educator, and the creative force behind ""&"" With a simple mission to help passioned healthcare professionals with "endless educational resources" across all career levels.

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