ACLS Study Guide

ACLS draws heavily on Basic Life Support (BLS). In fact, it is assumed that all people who are pursuing ACLS will be competent in the techniques of BLS—so much so that it is considered a prerequisite to ACLS

The first step in any resuscitation is to make sure the rescuers (you!) and the victim are safe. Therefore, if your victim is in the middle of the highway or in a burning building, the first step is to move the victim to safety.

Assuming you and the victim are in a safe location, the next step is to assess whether the patient is responsiv

If patient is not responsive, move to BLS survey
If patient is responsive, move to ACLS survey

Adult BLS is slightly different if there is one provider (solo) or more than one provider (team) present. The difference between solo provider BLS and team BLS is that responsibilities are shared when more than one person is present. These will be detailed in Solo and Team Adult BLS.

For healthcare providers, the difference between a witnessed cardiac arrest and a victim who is found down is the order of the initial steps.

• If you are alone and witness a victim suddenly collapse: Assume cardiac arrest with a shockable rhythm. If you can get an AED quickly, you may activate EMS, leave the victim to get an AED, provide CPR for 2 minutes, and use the AED.
• If you are alone and find an unresponsive adult: Tailor response to the prospective cause of injury.
  • If you suspect cardiac arrest: Activate EMS, get AED, 2 min of CPR, use AED
  • If you suspect asphyxia: 2 min of CPR, Activate EMS, get AED, use AED

• In Team CPR, the provider giving chest compressions changes every 2 minutes
• Keep going until EMS arrives or the victim regains spontaneous circulation.

Cardiac arrest is the sudden sensation cessation of blood flow to the tissues in brain the results from a heart that is not pumping effectively. Four rhythms may occur during cardiac arrest: ventricular fibrillation, pulseless ventricular tachycardia, pulseless electrical activity, and asystole. The primary intervention for ventricular fibrillation and pulseless ventricular tachycardia is unsynchronized cardioversion, more commonly known as a “shock.” The primary intervention for pulseless electrical activity and asystole is pharmacological, beginning with the administration of epinephrine.

While ACLS provides algorithms for each of these cardiac arrest rhythms, in the real world a patient may move between these rhythms during a single instance of cardiac arrest. Therefore, the provider must be able to accurately assess and adapt to changing circumstances. After every 2 minutes of CPR, check for a pulse and check the cardiac rhythm. If the rhythm has switched from shockable or to shockable, then switch algorithms.

In ventricular fibrillation or pulseless ventricular tachycardia, the heart’s conduction system exhibits a disordered rhythm that can sometimes be corrected by applying energy to it. This energy may come in the form of an automated external defibrillator (AED) defibrillator paddles, or defibrillator pads. VFib and VTach are treated with unsynchronized cardioversion, since there is no way for the defibrillator to decipher the disordered waveform. In fact, it is important not to provide synchronized shock for these rhythms.

Ventricular fibrillation is recognized by a disordered waveform, appearing as rapid peaks and valleys as shown in this ECG rhythm strip:

Ventricular tachycardia may provide waveform similar to any other tachycardia; however, the biggest difference in cardiac arrest is that the patient will not have a pulse and, consequently, will be unconscious and unresponsive. Two examples of ventricular tachycardia are shown in this ECG rhythm strips. The first is narrow complex tachycardia and the second is wide complex tachycardia:

• Once you have determined that a patient has a shockable rhythm, immediately provide an unsynchronized shock.
• If you are using biphasic energy, use recommended settings on the device. If you do not know what that setting is, use the highest available setting, (120 to 200 J).
• If you are using a monophasic energy source, administer 360 J.
• Resume CPR immediately after a shock. Minimize interruptions of chest compressions.Provide 2 rescue breaths for each 30 compressions.
• Epinephrine (1 mg IV/IO) is given every 3 to 5 minutes (two 2 minute cycles of CPR)
• Vasopressin (40 units IV/IO) can be used instead of the first or second dose of epinephrine
• Amiodarone (IV/IO)
  • First dose 300 mg
  • Second dose 150 mg

• Lidocaine may replace amiodarone when amiodarone is not available.
  • First dose: 1-1.5 mg/kg IV
  • Second dose: 0.5-0.75 mg/kg IV every 5 to 10 min
• If the arrest rhythm is no longer shockable, move to PEA/Asystole algorithm
• If the patient regains consciousness, move to ROSC algorithm for him and him

Pulseless electrical activity or PEA is a cardiac rhythm that does not create a palpable pulse is even though it should. A PEA rhythm can be almost any rhythm except ventricular fibrillation (incl. torsade de pointes) or pulseless ventricular tachycardia.

Asystole is the “flatline” on the ECG monitor. It represents a lack of electrical activity in the heart. It is critically important not to confuse true asystole with disconnected leads or an inappropriate gain setting on an in-hospital defibrillator. Asystole may also masquerade as a very fine ventricular fibrillation. If the ECG device is optimized and is functioning properly, a flatline rhythm is diagnosed as asystole. Note that asystole is also the rhythm one would expect from a person who has died. Consider halting ACLS efforts in people who have had prolonged asystole.

It is inappropriate to provide a shock to pulseless electrical activity or asystole. Cardiac function can only be recovered in PEA or asystole through the administration of medications.

• As long as the patient is in PEA or asystole, the rhythm is not shockable.
• Chest compressions/high-quality CPR should be interrupted as little as possible during resuscitation.
• After 2 min. of high-quality CPR, give 1 mg of epinephrine IV/IO.
• Remember, chest compressions are a means of artificial circulation, which should deliver the epinephrine to the heart. Without chest compressions, epinephrine is not likely to be effective.
• Chest compressions should be continued while epinephrine is administered.
• Rhythm checks every 2 min.

• Epinephrine (1 mg IV/IO) is given every 3 to 5 minutes (after two, 2 minute cycles of CPR)
• Vasopressin (40 units IV/IO) can be used instead of the first or second dose of epinephrine
• If the arrest rhythm becomes shockable, move to VFib/Pulseless VTach algorithm
• If the patient regains circulation, move to ROSC algorithm

In ACLS, the term airway is used to refer both to the pathway between the lungs and the outside world and victim in the devices that help keep that airway open. The simplest way to “manage an airway” is the head tilt-chin lift, which creates the straightest passageway for air to flow into the lungs. As if the victim may have experienced head or neck trauma, airway management should include a jaw thrust, which leaves the head and neck unmoved, but which opens up the airway.

If one is to use a pocket mask or a bag mask to perform ventilations, it is important to make a tight seal with a mask on the victim’s face. Proper use of these masks may require the rescuer to use one or even two hands to secure the mask to the victim’s face.

A nasopharyngeal airway, which extends from the nose to the pharynx, can be used in both conscious and unconscious patients. An oropharyngeal airway can only be used in unconscious patients because it may stimulate the gag reflex.
Advanced airways such as endotracheal tubes (ET tubes) and laryngeal mask airways (LMAs) usually require specialized training, but are useful in-hospital resuscitations (especially LMAs).

While nasopharyngeal and oropharyngeal airways are basic airways, they do require a bit of preparation and skill to use correctly.

• The patient who has been successfully resuscitated will regain spontaneous circulation.
• You can detect spontaneous circulation by feeling a palpable pulse at the carotid artery.
• Even after Return of Spontaneous Circulation (ROSC), the patient still needs close attention and support. The patient is at risk for reentering cardiac arrest at any time. Therefore, the patient should be moved to an intensive care unit.
• Titrate the patient’s blood oxygen levels to ≥94%
• Does the person need an advanced airway? If so, it should be placed.
• Add quantitative waveform capnography
• Titrate the patient’s systolic blood pressure to at least 90 mmHg. this may require the addition of fluids and/or vasopressors o Epinephrine IV 0.1-0.5 mcg/kg/min o Dopamine IV 5-10 mcg/kg/min o Norepinephrine IV 0.1-0.5 mcg/kg/min o 1-2 liters of fluid resuscitation
• Does the person follow verbal commands? If not, there may be neurological compromise. Consider inducing therapeutic hypothermia with 4°C fluids during fluid resuscitation.
• Does the person have signs of myocardial infarction by ECG? Move to ACS algorithm.

Many different disease processes and traumatic events can cause cardiac arrest, but in an emergency, it is important to be able to rapidly consider and eliminate or treat the most typical causes of cardiac arrest. To facilitate remembering the main, reversible causes of cardiac arrest, they can be organized as the Hs and the Ts.

• Bradycardia is any heart rate less than 60 bpm. In practice, however, bradycardia is only a concern if it is unusual or abnormal for the patient or causing symptoms.
• New cases of bradycardia should be evaluated, but most will not require specific treatment.
• Evaluation of bradycardia includes cardiac and blood oxygen monitoring and a 12 lead ECG if available.
• Bradycardia may be treated by providing supplemental oxygen and supporting the patient’s airway if needed.
• Unstable bradycardia (i.e., an abnormally slow heart rate that causes altered mental status, hypotension, symptoms of shock, cardiac chest pain, or new signs and symptoms of heart failure) should be treated immediately.
• Unstable bradycardia is first treated with intravenous atropine at a dose of 0.5 mg. Additional doses can be given every 3 to 5 min. up to a maximum of 3 mg. Pulseless bradycardia is considered PEA.

• If atropine is unsuccessful in treating symptomatic, unstable bradycardia, consider transcutaneous pacing, dopamine or norepinephrine infusion, or transvenous pacing. An intensive or cardiologist may need to be consulted for these interventions and the patient may need to be moved to the intensive care unit

Atrial fibrillation is the most common arrhythmia. It is diagnosed by electrocardiogram, specifically the RR intervals follow no repetitive pattern. Some leads may show P waves while most leads do not. Atrial contraction rates may exceed 300 bpm. The ventricular rate often range is between 100 to 180 bpm. The pulse may be “irregularly irregular.”

Atrial flutter is a cardiac arrhythmia that generates rapid, regular atrial depolarizations at a rate of about 300 bpm. This often translates to a regular ventricular rate of 150 bpm, but may be far less if there is a 3:1 or 4:1 conduction. By electrocardiogram, or atrial flutter is recognized by a sawtooth pattern sometimes called F waves. These waves are most notable in leads II, III, and aVF

Narrow QRS complex tachycardias include several different tachyarrhythmias. A narrow QRS complex tachycardia is distinguished by a QRS complex of less than 120 ms. One of the more common narrow complex tachycardias is supraventricular tachycardia, shown below.

Wide complex tachycardias are difficult to distinguish from ventricular tachycardia. Ventricular tachycardia leading to cardiac arrest should be treated using the ventricular tachycardia algorithm. A wide complex tachycardia in a conscious person should be treated using the tachycardia algorithm.

• Tachycardia is any heart rate greater than 100 bpm. In practice, however, tachycardia is usually only a concern if it is
• New cases of tachycardia should be evaluated with cardiac and blood oxygen monitoring and a 12 lead ECG if available.
• Tachycardia may be treated by providing supplemental oxygen, supporting the patient’s airway if needed, vagal maneuvers, and IV adenosine.
• Adenosine IV rapid push
  • First dose: 6 mg
  • Second dose: 12 mg
• Unstable tachycardia (i.e., an abnormally slow heart rate that causes altered mental status, hypotension, symptoms of shock, cardiac chest pain, or new signs and symptoms of heart failure) should be treated with synchronized cardioversion or adenosine. Consider beta-blocker or calcium channel blocker.
• Wide QRS tachycardia may require antiarrhythmic drugs.

Atrioventricular block or heart block is a failure of the heart’s electrical system to properly coordinate conduction. There are four main types of atrioventricular block: first degree, second degree type I, second degree type II, and third degree heart block. The types of second degree heart block are referred to as Mobitz type I and Mobitz type II. Second degree heart block Mobitz type I is also known as the Wenckebach phenomenon.

Atrioventricular blocks may be acute or chronic. Chronic heart block may be treated with pacemaker devices. From the perspective of ACLS assessment and intervention, heart block is important because it can cause hemodynamic instability and can evolve into cardiac arrest. In ACLS, heart block is often treated as a bradyarrhythmia.

The PR interval is a consistent size, but longer or larger than it should be in first degree heart block.

The PR interval increases in size until a QRS complexes dropped, resulting in missed “beat.”

A QRS wave will occasionally drop, though the PR interval is the same size.

Complete dissociation between P waves and the QRS complex. No atrial impulses reach the ventricle.