A lot of content in ACLS training courses focuses on learning and applying the rhythm-based algorithms, and return of spontaneous circulation (ROSC) is a favorable outcome of those processes. When a patient reaches ROSC, the team reaches a new stage of care in the ACLS algorithm.

For an ACLS team, ROSC is cause to celebrate! It means that life-saving interventions have produced some results. However the team must still proceed carefully and follow evidenced-based interventions to manage this new phase. Learning more about ROSC is important for ACLS clinicians to understand the entire continuum of care and how to optimize patient outcomes.

What is ROSC?

Return of spontaneous circulation (ROSC) is defined as “the resumption of sustained perfusing cardiac activity associated with significant respiratory effort after cardiac arrest.” Team members continuously assess for ROSC by observing the patient’s color, any movement, respiratory effort, and by frequently checking for a pulse.

It is important to understand that while ROSC is an event, it is also a phase of care that is unstable and requires team action. In other words, while the initial goal is accomplished — don’t make the mistake of thinking the ACLS event is over.

Signs of ROSC

The signs that indicate ROSC will be first observed in the patient and then verified by vital signs and cardiac monitoring. Patient spontaneous movement, coughing, sustained breathing, a palpable pulse, and measurable blood pressure all indicate ROSC. Although these signs are indicative that resuscitation efforts have been successful, remember that the patient is still unstable, the cause of the initial arrest may still be present. Plus, the patient likely has multiple medications circulating in their system that will begin to wear off.

It is also important to understand that ROSC is not necessarily a linear process. Patients can reach ROSC and then revert back into cardiac arrest. They may even do so multiple times until the underlying cause is corrected. The ACLS team should be able to quickly pivot back to the correct ACLS algorithm based on the patient’s cardiac rhythm.

The Lazarus Phenomenon

One interesting phenomenon that can occur (although rarely) is called the Lazarus phenomenon. The phenomenon is defined as the delayed return of ROSC after CPR has ceased.

There are at least 38 reported cases of this happening since 1982 when the phenomenon was first described in the literature. These anecdotes describe patients “waking up” minutes or even hours after being declared dead — and around 45% of them experienced good neurological recovery. Theories to explain this vary. Delayed action of uncirculated medications is one theory, while a buildup of pressure in the chest from CPR kickstarting the heart is another. The truth is, there is no great explanation for why this occurs.

How to Achieve ROSC

Several ACLS situations involve loss of circulation, particularly ventricular tachycardia (VT), ventricular fibrillation (VF), pulseless electrical activity (PEA), and asystole. Other conditions that activate an ACLS response, like supraventricular tachycardia (SVT), bradycardia, atrial fibrillation, and various blocks may be symptomatic and require a response, while there is no loss of circulation (pulse and measurable blood pressure).

Clearly, the patient in cardiac arrest with no pulse is in dire straits. It is up to the clinical team to provide the quality CPR and ACLS care that gives the patient the best possible chance at ROSC.

Tips to Maximize ROSC Success

At the point that an ACLS response to cardiac arrest is in progress, there are always two possible outcomes: ROSC, or no ROSC. In that, there are important things that the team can do to maximize the patient’s chance of ROSC and a favorable post-ROSC outcome.

• High Quality CPR - When a patient is in ROSC, it is important to realize that high-quality CPR is imperative. Vigorous chest compressions with adequate depth and recoil provide the cardiac perfusion pressure (CPP) that acts as a substitute for myocardial perfusion. One study suggests that a minimum of 15 mmHg of CPP was necessary for ROSC, and more importantly, that CPP was predictive of ROSC. To give your patient the very best chance at ROSC, effective CPR is critical.
• Timely Defibrillation - Prompt defibrillation (if indicated) and first shock success have been linked to increased ROSC rates and higher survival rates. This fact has been supported by several studies and is the primary motivation for placing AEDs in public locations like airports, stadiums, schools, and other places where crowds gather.
• Administering  the Right Medications (at the right times) - Medications are included in the ACLS algorithm specifically because they increase the patient’s chances for ROSC. For example, in one study of antiarrhythmic drugs used during cardiac arrest, the proportion of patients who had ROSC decreased as time to amiodarone administration increased. Epinephrine dosing has been extensively studied and has been shown to increase coronary blood flow, which is associated with an increased chance of return of ROSC.
• Analyzing Possible Causes - While all of these ACLS interventions are ongoing to try and achieve ROSC, the team should also be going through possible causes. Once ROSC is obtained, the patient’s long-term success depends on reversing the cause and maintaining hemodynamic stabilization.

The Patient has ROSC, Now What?

Now that the patient has reached ROSC, the real work begins. This phase of care is critical to the patient’s long-term chances of survival. Unfortunately, up to two-thirds of patients with return of spontaneous circulation do not survive long enough to be discharged from the hospital. To increase the chances for survival, it’s critical to take quick action according to the best practices.

The ACLS Post-Cardiac Arrest Care Algorithm begins with ROSC and divides subsequent activities into two phases:

1. Initial stabilization phase: This includes airway management and hemodynamic stabilization of oxygenation, PaCO2 levels, blood pressure, and MAP. A 12-lead EKG should also be obtained.
2. Continued management and additional emergent activities phase: Consider emergent cardiac intervention if STEMI is present, the patient is in unstable cardiogenic shock, or mechanical circulatory support is required. During this phase, an initial neurological assessment should be conducted to assess a baseline condition, and further testing such as an EEG or brain CT should be considered.

Additionally, the algorithm reminds the team to evaluate and treat rapidly reversible causes, commonly termed the “H’s and T’s” for easy recall.

Post Cardiac Arrest Syndrome

ACLS-trained clinicians should also be aware of post-cardiac arrest syndrome, a complex set of pathophysiological processes that happens after ROSC. Because of this syndrome, careful ICU monitoring should be in place to watch for the following:

• Post-arrest brain injury
• Post-arrest myocardial infarction
• Systemic ischemia
• Reperfusion response
• Underlying pathology (acute or chronic) that contributed to the cardiac arrest itself

Each facility should have an easily accessible ROSC policy and procedure, usually accompanied by a care plan and checklist. Each member of the ACLS team should be very familiar with the facility’s processes and understand their role(s).

All organizational post-ROSC plans of care should include the following components:

• Targeted temperature management (TTM) - This intervention aims at maintaining the core body temperature at either hypothermia or normothermia, to maximize neurological recovery.
• Hemodynamic and ventilation optimization - This phase includes titrating ventilator settings for an FI02 > 94% and adjusting IV infusions to maintain SBP > 90.
• Immediate coronary reperfusion - This includes percutaneous coronary intervention (PCI) for eligible patients as soon as possible.
• Neurological care - A complete neurological assessment, consulting neurology, and performing recommended tests such as EEG and CT brain scans.
• Other targeted interventions - (Such as diagnostic testing and line placements). These interventions include, but are not limited to, arterial blood gasses, full metabolic panels, cultures, and ongoing monitoring via arterial lines.

Further Research about ROSC

Post-ROSC care has been adjusted over the years as new studies emerge, and will likely continue to evolve. The goal of ROSC is always to promote the best possible long-term outcomes for the patient, and there are various sources of information on how to accomplish that.

Some of the current topics being studied in relation to ROSC are:

• How to improve the quality and timing of CPR and post-resuscitation care
• How to identify the optimal timing and indications for coronary angiography
• How to use electrocardiogram and other biomarkers to predict ROSC and prognosis
• How to implement targeted temperature management and other neuroprotective strategies
• How to optimize the use of extracorporeal life support and other advanced therapies
• How to enhance the recovery and quality of life of cardiac arrest survivors

Learn More About ROSC and ACLS

It is easy to become overloaded with information when learning about ROSC and post-resuscitation care. After all, there are a lot of scenarios to think about and a lot of interventions needed. It is important for ACLS clinicians to remember the basics — always using high-quality CPR, following the ACLS algorithms, and practicing effective team dynamics to give the patient the best possible chance for attaining ROSC. Rather than an end goal, ROSC should be considered a milestone. From there, even more work begins to monitor the patient’s hemodynamic status and seek to optimize outcomes.

If you would like to learn more about the drugs, ECG rhythms, clinical scenarios, and other topics related to ACLS, AMRI has study materials to help you develop a better understanding. Accredited by the National Board of Emergency Care Certifications (NBECC), AMRI has helped more than one million medical professionals become certified or recertified in ACLS, BLS, and PALS since 1983.

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