Adult Cardiac Arrest Algorithm
Algorithm at a Glance
- The rescuer immediately recognizes cardiac arrest and begins high-quality CPR.
- The team determines if the cardiac arrest rhythm is shockable (VF or pVT) or nonshockable (PEA and asystole).
- If the rhythm is shockable, the team administers a shock as soon as a defibrillator is available.
- If the rhythm is not shockable, the team administers epinephrine as early as possible and every 3–5 minutes after that.
- High-quality CPR continues if the patient is in cardiac arrest.
- For VF or pVT, the team considers antiarrhythmics if defibrillation is not successful.
Related Video – Understanding the Adult Cardiac Arrest Algorithm
Goals for the Management
The responder must succeed in the following goals to successfully manage cardiac arrest:
- Recognize the rhythms of cardiac arrest: ventricular fibrillation, ventricular tachycardia, PEA, and asystole
- Recognize the Hs and Ts as possible causes of cardiac arrest
- Appropriately intervene in cardiac arrest depending on the cardiac arrest rhythm
Adult Cardiac Arrest Algorithm Explained
This algorithm was created to present the steps for assessing and managing patients presenting with cardiac arrest symptoms.
The ACLS responder must be able to recognize the rhythms indicative of cardiac arrest on a cardiac monitor. Understanding the basics of these rhythms allows the user to identify them quickly.
ECG Characteristics of Shockable Cardiac Arrest Rhythms
- VF – appears as voltage fluctuations on the ECG strip; amplitude is characterized as coarse (early VF) or fine (late VF).
- pVT – the patient does not exhibit a pulse; pVT appears as a fast and typically regular rhythm with wide QRS complexes on ECG and no P waves.
ECG Characteristics of Nonshockable Cardiac Arrest Rhythms
- Asystole – complete absence of electrical activity depicted by a flat line on the ECG
- PEA – exhibits an organized rhythm, but there is no palpable pulse
Box 0: Ensuring Scene Safety
Particularly for OHCA, it is critical that the rescuer first ensure the scene is safe for both the patient and the team.
Box 1: Identifying Cardiac Arrest and Initiating CPR
Ideally, the team performs rhythm-based management of cardiac arrest. If there is no pulse, the rescuers initiate high-quality CPR. If oxygen and a monitor/defibrillator are available, the team attaches those as CPR continues.
Box 2: Identifying Shockable Rhythms
If the rhythm is shockable (VF or pVT), the team proceeds to Box 3. If the rhythm is not shockable(asystole or PEA), they proceed to Box 9.
Related Video – ECG Rhythm Review – Ventricular Fibrillation
Related Video – ECG Rhythm Review – Polymorphic Ventricular Tachycardia (Torsades de Pointes)
Related Video – ECG Rhythm Review – Asystole
Related Video – What is PEA?
Box 3: Administering Shock
When using a manual defibrillator, the first rescuer performs chest compressions while the defibrillator is charging. Once charged, the rescuer stops chest compressions, and the second team member instructs everyone to clear the patient. Once everyone is clear of the patient, the second rescuer delivers a shock at the dosage recommended by the defibrillator manufacturer.
Energy Dose for Shock
- First shock – refer to manufacturer’s recommendation or highest dose available (if the recommended shock dose is unknown)
- Subsequent shocks – refer to manufacturer’s recommendations or escalating energies (higher for second and subsequent shocks)
Note: For monophasic defibrillators, the initial shock dose is a standard 360 J and for subsequent shocks.
Studies show that biphasic manual defibrillators are preferred over monophasic defibrillators for the treatment of atrial and ventricular arrhythmias.
Biphasic waveform defibrillators set to deliver 200 J or less for the first shock were shown to be efficacious.
The first dose of shock delivery depends on the manufacturer’s recommended energy dose. If the rescuer does not know the manufacturer’s recommended dose, they should consider the maximal dose for the first and all shocks following.
If VF recurs after a successful shock is delivered, the team should deliver subsequent shocks with the same dose.
When using a monophasic defibrillator, 360 J should be used for the first shock and for recurrent episodes.
Box 4: Continuing High-Quality CPR
The team minimizes CPR interruptions by immediately performing chest compressions after a shock. At this point in the algorithm, it is important to obtain IV or IO (intraosseous) access in anticipation of drug delivery.
Auto-compression devices are tested on a manikin.
Clinicians should pay attention to ETCO2 monitoring.
Box 5: Rhythm Check and Shock Administration
After 2 minutes of high-quality CPR, the team rechecks the patient’s rhythm. If there is continued VF or pVT, they prepare to administer another shock. The rhythm check should be as brief as possible and CPR resumed immediately afterward.
Box 6: Epinephrine and Consideration for Advanced Airway
Once the team delivers the shock, they resume high-quality CPR immediately. At this point, two shocks have been delivered, and vascular access is available. High-quality CPR is ongoing.
It is now time to utilize drug therapy to restore a perfusing rhythm. The first-line medication for the treatment of VF or pVT is epinephrine.
A cardiac arrest patient may receive epinephrine when feasible after the placement of vascular access. Studies of IHCA patients show an increased chance for ROSC if epinephrine is given within 1 to 3 minutes of cardiac arrest as opposed to after 3 minutes.
For OHCA patients, studies show increased rates of ROSC if epinephrine is given 9 minutes or less from the onset of cardiac arrest compared with patients given epinephrine later.
Epinephrine 1:10,000 box package revision.
Rescuer on far right is preparing medication.
Administering Epinephrine
The recommendations for treating cardiac arrest are for epinephrine intravenously or via the intraosseous route with a preparation of 1:10,000 dilution, 1 mg every 3 to 5 minutes. Studies show that this standard dose is responsible for improved survival and ROSC.
The addition of vasopressin does not deliver any advantage over using epinephrine alone. Thus, the AHA no longer recommends vasopressin as a treatment in cardiac arrest.
Key Takeaway
- Recommendations no longer suggest vasopressin as a treatment choice in cardiac arrest.
The effects of epinephrine include:
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- Vasoconstriction, which causes increased perfusion to the heart and brain
- Increased cardiac output resulting in:
- Increased heart rate
- Increased heart contractility
- Increased conductivity of impulses through the AV node
Considering Advanced Airway
In Box 6, in addition to administering epinephrine, responders are directed to consider the insertion of an advanced airway. This is not always necessary if the patient is being ventilated adequately using a bag-mask.
A bag mask provides manual ventilation to patients.
Ideally, two rescuers are needed to ventilate effectively with a bag-mask. One obtains a tight seal with the mask over the patient’s mouth and nose. The second rescuer delivers each ventilation at the correct time in the CPR sequence (2 breaths are given after 30 compressions) and at sufficient volume to cause the chest to rise but avoiding excessive ventilation. These are essential components of high-quality CPR.
When it is determined that an advanced airway is needed, there are several essential points the team must remember:
- Inserting an advanced airway can lead to unacceptable delays in the provision of CPR.
- Only those team members with expertise should attempt insertion of an advanced airway.
- Once inserted, proper placement must be determined by both physical confirmation (equal bilateral chest rise, air entry heard in all lung fields, and no air auscultated over the epigastrium)and physiologic monitoring (waveform capnography).
- The advanced airway is then secured in place, with placement frequently checked to detect any complications, such as dislodgement.
- Once an advanced airway is in place, ventilation and compressions no longer need to be synchronous. The compressor provides continuous chest compressions, while the ventilator provides one breath every 6 seconds.
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Note: For more information on advanced airways and ventilation during cardiac arrest, see the chapter on adjuncts.
Box 7: Rhythm Check and Shock Administration
Once the initial dose of epinephrine has been given and 2 minutes have passed since the last shock, the team pauses CPR to perform another rhythm check. If the patient’s rhythm is unchanged or refractory (patient remains in VT or pVT), another shock is administered.
Box 8: Administering Antiarrhythmic and Considering Possible Causes
Once the team administers the shock, they should immediately resume CPR for 2 minutes.
Amiodarone is given for VF or pVT refractory to defibrillation, CPR, and vasopressor therapy. Lidocaine is an alternative treatment to replace amiodarone. Both drugs are given IV and IO.
Amiodarone is administered for VF or pVT after defibrillation, CPR, and vasopressor therapy.
Antiarrhythmic Drugs During and Immediately After Cardiac Arrest
Amiodarone is administered for VF or pVT refractory to defibrillation, CPR, and vasopressor therapy. Lidocaine is an alternative treatment for amiodarone. Both drugs may be given intravenously and via the intraosseous route.
Related Video – Amiodarone – ACLS Drugs
Reversible Conditions
The team leader continues to seek and identify possible reversible causes of arrest, including
- Hypoxia
- Hypovolemia
- Hydrogen ion excess
- Hypo-or hyperkalemia
- Hypothermia
- Tension pneumothorax
- Tamponade, cardiac
- Toxins
- Thrombosis, coronary
- Thrombosis, pulmonary
Preparation of antiarrhythmic Drugs in Cardiac Arrest
- Amiodarone – First dose 300 mg IV/IO push, then 150 mg IV/IO push for subsequent doses
- Lidocaine – First dose 1.0 to 1.5 mg/kg as IV/IO push, then 0.5-0.75 mg/kg IV push for a maximum of 3 doses or a total of 3 mg/kg
Box 9: Is Rhythm Asystole or PEA?
Asystole and PEA are the two cardiac arrest rhythms that are not shockable. As soon as one of these rhythms is identified, the team administers epinephrine.
Box 10: CPR Resumes for 2 minutes
The team administers epinephrine every 3–5 minutes.
At this point, the team leader considers an advanced airway and waveform capnography. After 2 minutes of high-quality CPR, the team stops briefly for a rhythm check.
Box 11: High-Quality CPR Continues If the Rhythm Is Not Shockable
The team leader assesses for treatable causes of cardiac arrest. If the rhythm is shockable at any time, the team proceeds to Box 5 or 7.
Box 12: ROSC?
If there are no signs of ROSC, the team returns to Box 10 or 11. If there are signs of ROSC, they proceed to the Post-Cardiac Arrest Care algorithm.
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