Part 7: Adult Basic Life Support

What does OHCA stand for?

Out-of-hospital cardiac arrest.

What does IHCA stand for?

In-hospital cardiac arrest.

What is the 2030 Impact Goal for the proportion of adults with cardiac arrest who receive bystander CPR?

Greater than 50%.

What is the 2030 Impact Goal for the proportion of adults with cardiac arrest for whom an AED is applied before EMS arrives?

Greater than 20%.

What are the first two 2030 Impact Goals related to?

Basic life support

What is public-access defibrillation?

The use of an AED by the public/bystanders before emergency medical responders arrive.

What is CARES?

The Cardiac Arrest Registry to Enhance Survival, a voluntary database used by EMS agencies and hospitals to track and benchmark OHCA performance and outcomes.

What does the Chain of Survival aim to do?

Strengthen the links needed to prevent, identify, treat, and support people at risk for or experiencing cardiac arrest.

How many adults are estimated to be treated by EMS annually for out-of-hospital cardiac arrest (OHCA) in the United States?

Approximately 356,000 adults per year.

What is the estimated annual incidence of adult OHCA per 100,000 people in the United States?

Approximately 83 per 100,000 people.

What percentage of adults experiencing OHCA survived to hospital discharge according to CARES data from 2024?

10.5%

What percentage of adults experiencing OHCA had a favorable neurologic outcome according to CARES data from 2024?

Approximately 8.2%.

Where does the majority of adult OHCA occur?

Private residences.

What percentage of adult OHCA occurred in public places?

18%

How often was bystander CPR provided in adult OHCA cases according to 2024 CARES data?

47.7% of cases.

How often did a bystander use an AED in adult OHCA cases according to 2024 CARES data?

7.9% of cases.

What is the estimated annual incidence of adult in-hospital cardiac arrest (IHCA) in the United States?

Approximately 292,000 cases per year.

Where does approximately 60% of adult IHCA occur?

In an acute-care setting, such as an intensive care unit, emergency department, or operating room.

Where does approximately 40% of adult IHCA occur?

On general inpatient units.

What was the survival-to-hospital-discharge rate for IHCA before the COVID-19 pandemic, according to the passage?

26.7%

To what low did IHCA survival to hospital discharge decrease during the COVID-19 pandemic?

18.8%.

What was IHCA survival to hospital discharge in 2023?

23.6%

What does CARES stand for?

Cardiac Arrest Registry to Enhance Survival.

What is CARES used for?

EMS agencies and hospitals use it to generate reports and benchmark performance and outcomes against similar systems.

When was CARES developed?

2004.

How many states had participating CARES sites according to the passage?

37 states.

Approximately what percentage of the U.S. population was covered by CARES participating sites?

Approximately 56%.

What populations have been identified as experiencing disparities in cardiac-arrest outcomes?

Differences have been observed based on geographic region, race, sex, and socioeconomic status.

Which guidelines (adult or pediatric) should you use for an unresponsive person in cardiac arrest who shows signs of puberty?

Use the Adult Basic Life Support Guidelines.

What does COR (Class of Recommendation) reflect?

The strength of the recommendation, based on the evidence, potential impact on patient outcomes, and factors such as feasibility, acceptability, and equity.

What does LOE (Level of Evidence) reflect?

The quality of the evidence supporting a recommendation.

What wording is reserved for a Class 1 recommendation?

“Is recommended” or “should.”

What is the highest Level of Evidence?

LOE A, based on randomized controlled trials (RCTs) and meta-analyses involving RCTs.

What does a lower LOE generally indicate?

The supporting evidence comes from lower-quality randomized/nonrandomized, registry, or observational studies, or from limited data/expert opinion.

Why are COR and LOE assigned to each recommendation?

To show users how strong the recommendation is and how strong the supporting evidence is, while identifying areas where more research could change future guidelines.

Are COR and LOE the same thing?

No. COR = strength of the recommendation; LOE = quality of the evidence.

What does COR stand for, and what does it tell you?

Class of Recommendation — it tells you the strength of the recommendation.

What does LOE stand for, and what does it tell you?

Level of Evidence — it tells you the quality of the evidence supporting the recommendation.

What is Class 1 (Strong)?

Benefit >>> Risk. The intervention is recommended/indicated and should be performed when appropriate.

What is Class 2a (Moderate)?

Benefit >> Risk. The intervention is reasonable or can be useful/effective/beneficial.

What is Class 2b (Weak)?

Benefit > Risk, but the usefulness/effectiveness is less certain. It may/might be reasonable or may/might be considered.

What does Class 3: No Benefit mean?

Benefit = Risk. The intervention is not recommended because it provides no benefit.

What does Class 3: Harm mean?

Risk > Benefit. The intervention is potentially harmful and should not be performed.

What is Level A evidence?

High-quality evidence, including evidence from more than one RCT, high-quality RCT meta-analyses, or RCTs supported by high-quality registry studies.

What does B-R mean?

B = moderate-quality evidence; R = randomized. It is based on one or more moderate-quality RCTs or meta-analyses of moderate-quality RCTs.

What does B-NR mean?

B = moderate-quality evidence; NR = nonrandomized. It comes from well-designed nonrandomized, observational, or registry studies.

What does C-LD mean?

Limited Data. Evidence comes from studies with limitations, meta-analyses of such studies, or physiological/mechanistic studies in humans.

What does C-EO mean?

Expert Opinion — consensus of expert opinion based on clinical experience.

Does a lower LOE automatically mean the recommendation is weak?

NO. COR and LOE are determined independently. Any COR can be paired with any LOE

What is the difference between COR and LOE?

COR = How strongly should we recommend it?

LOE = How strong/quality is the evidence?

What are the COR categories in order?

1 → 2a → 2b → 3 No Benefit → 3 Harm

What are the LOE categories from highest to lowest?

A → B-R → B-NR → C-LD → C-EO

How long should a healthcare professional check for a pulse?

No more than 10 seconds. If no definite pulse is felt, assume cardiac arrest and begin CPR.  

What is agonal breathing?

Slow, irregular gasping respirations that are ineffective for ventilation.

How common is agonal breathing in out-of-hospital cardiac arrest (OHCA)?

It is reported in up to 40%–60% of OHCA cases.

Why is agonal breathing dangerous for recognition of cardiac arrest?

Lay rescuers may mistake it for normal breathing, causing delays in starting CPR.

Lay rescuer vs. healthcare professional — how do they recognize cardiac arrest?

Lay rescuer: Unresponsive + absent/abnormal breathing → assume cardiac arrest

Healthcare professional: Unresponsive + absent/abnormal breathing → check pulse ≤10 sec → if no definite pulse → CPR

If a second lay rescuer is present, what can they do while the first rescuer begins CPR?

The second rescuer can call 911 and activate the emergency response system.

What type of CPR is appropriate for an untrained or unwilling lay rescuer?

Chest compression-only CPR.

What is recommended for a lay rescuer who is trained in CPR when an adult is in cardiac arrest?

Provide chest compressions and rescue breaths. CPR with breaths may improve outcomes compared with compression-only CPR.

When is it reasonable for rescuers to use personal protective equipment (PPE) during CPR?

When PPE is immediately available.

Why is PPE useful during CPR?

It provides a barrier against infectious diseases. However, lay rescuers may have limited access to PPE.

Why start CPR if cardiac arrest is suspected but unconfirmed?

The risk of withholding CPR from a victim is severe, while the potential harm from unnecessary chest compressions is very low.

What potential disadvantages can wearing PPE have during CPR?

PPE may:

Delay the initiation of CPR while the rescuer puts it on.

Make CPR more difficult or affect performance.

Increase rescuer fatigue.

During adult cardiac arrest, what should healthcare professionals provide, regardless of whether the arrest has a cardiac or noncardiac cause?

Chest compressions and ventilations. Providing both helps maintain circulation and oxygenation.

Why do hands-only compressions lose effectiveness during prolonged or asphyxial CPR?

Arterial oxygen depletes over time. Ventilation becomes essential to restore oxygenation, especially if the arrest was caused by lack of oxygen (asphyxia).

What maneuver should a rescuer use to open the airway of an unresponsive adult when no cervical spine injury is suspected?

The head-tilt, chin-lift maneuver.

Why can an unresponsive person’s airway become obstructed?

As muscle tone decreases, the tongue can fall backward and obstruct the oropharynx.

What can happen if an airway obstruction is not corrected?

It can cause hypoxia (insufficient oxygen) and hypercarbia (excess carbon dioxide), potentially worsening the patient’s condition or contributing to cardiac arrest.

What are two examples of airway adjuncts used to help maintain an adult patient’s airway?

• Oropharyngeal airway (OPA)

• Nasopharyngeal airway (NPA)

What is the purpose of an oropharyngeal or nasopharyngeal airway?

To help maintain airway patency by preventing the tongue from obstructing airflow and to facilitate ventilation.

In which unresponsive adult patients may an airway adjunct be reasonable to facilitate ventilation?

Patients who have no cough or gag reflex.

When a patient has a known or suspected basilar skull fracture or severe coagulopathy, which airway adjunct is preferred: an OPA or an NPA?

An oropharyngeal airway (OPA) is preferred because an NPA may cause serious complications, including intracranial placement in patients with a basilar skull fracture.

Is routine cricoid pressure recommended during adult cardiac arrest?

No. Routine cricoid pressure is not recommended because it has no established benefit and may interfere with ventilation.

Why may cricoid pressure be harmful during resuscitation?

It may impede air entry into the trachea during bag-mask ventilation and may interfere with advanced airway placement.

What airway-opening maneuver should a trained rescuer use for an adult with suspected head or neck trauma?

The jaw-thrust maneuver without head extension, to minimize movement of the head and neck.

If the jaw-thrust maneuver and insertion of an airway adjunct fail to open the airway of an adult with head and neck trauma, what should a trained rescuer do?

Use the head-tilt, chin-lift maneuver to open the airway.

Should lay rescuers use rigid cervical collars on adults with suspected head and neck trauma?

No. Lay rescuers should not use rigid cervical devices for spinal motion restriction because they may be harmful and interfere with airway management and ventilation.

An adult experiences cardiac arrest while lying prone (face down). What is the preferred approach?

If feasible and safe, turn the patient supine (onto their back) before beginning chest compressions, provided doing so does not delay CPR.

What may rescuers consider if an adult in cardiac arrest cannot be safely turned from prone to supine?

Performing CPR in the prone position may be reasonable.

During adult CPR, what hand-positioning adjustment may improve chest compression quality?

Placing the dominant hand directly on the sternum may improve chest compression quality.

When should rescuers switch chest compressors?

Approximately every 2 minutes.

What is chest compression fraction (CCF)?

The percentage of resuscitation time spent performing chest compressions.

What is the suggested minimum CCF target?

At least 60%; high-performance teams may exceed 80%.

What is the compression-to-ventilation ratio for adult CPR without an advanced airway?

30:2 (30 compressions, 2 breaths).

How long should each rescue breath take?

Approx. 1 second

How deep should chest compressions be for an average adult?

At least 2 inches (5 cm).

What is the maximum recommended adult chest compression depth?

Avoid depths greater than 2.4 inches (6 cm).

What is the recommended chest compression rate for adults?

100–120 compressions per minute.

Why should rescuers avoid leaning on the chest between compressions?

To allow complete chest recoil, helping the heart refill with blood.

During chest compressions, how should compression time compare with recoil time?

They should be approx. equal

What are 3 methods of providing breaths during adult cardiac arrest without an advanced airway?

Mouth-to-mouth, mouth-to-mask, or bag-mask ventilation.

During bag-mask ventilation, what is the preferred technique when 2 trained rescuers are available?

One rescuer uses both hands to open the airway and seal the mask; the second squeezes the bag.

Why is two-rescuer bag-mask ventilation preferred?

It generally provides a better mask seal and more effective ventilation.

What is the E-C clamp technique used for?

To seal a bag-mask to the face and open the airway using one hand.

What can excessive ventilation cause?

Gastric inflation, regurgitation, aspiration, and decreased cardiac output.

Why should rescuers avoid taking deep breaths when giving mouth-to-mouth ventilation?

Regular-sized breaths can help prevent dizziness and overinflation of the person’s lungs.

When can mouth-to-nose ventilation be used for an adult in cardiac arrest?

When ventilation through the mouth is impossible or impractical.

How can you provide ventilation to an adult with a tracheostoma?

Use mouth-to-stoma or face mask-to-stoma ventilation.

Why is prompt ventilation especially important during respiratory arrest?

Severe oxygen deprivation can rapidly progress to cardiac arrest.