CPR BLS for Healthcare Providers 1 — Questions and Answers

Question 1: What is the recommended compression-to-ventilation ratio for single-rescuer adult CPR in the BLS for Healthcare Providers course?

15:2
30:2 (Correct answer)
5:1
10:2

Correct answer: 30:2

The 30:2 ratio is the standard for single-rescuer adult CPR, minimizing interruptions to compressions while providing adequate ventilation.

The American Heart Association BLS guidelines specify a 30:2 compression-to-ventilation ratio for single-rescuer adult CPR. This ratio was chosen to balance the benefits of chest compressions (maintaining coronary and cerebral perfusion pressure) with the need for ventilation. Frequent interruptions to deliver breaths decrease the mean coronary perfusion pressure significantly, reducing survival rates. The 30:2 ratio keeps pauses brief while still delivering necessary oxygenation.

Question 2: In the BLS for Healthcare Providers course, what is the correct compression depth for adult CPR?

1-1.5 inches
At least 2 inches but no more than 2.4 inches (Correct answer)
3 inches
1.5-2 inches

Correct answer: At least 2 inches but no more than 2.4 inches

AHA guidelines recommend at least 2 inches (5 cm) but no more than 2.4 inches (6 cm) for adult chest compressions to ensure adequate perfusion without injury.

The AHA 2020 Guidelines specify adult chest compression depth of at least 2 inches (5 cm) but caution against exceeding 2.4 inches (6 cm). Compressions that are too shallow fail to generate adequate blood flow, while compressions that are too deep can cause injury such as rib fractures, liver lacerations, or aortic damage. Proper hand placement on the lower half of the sternum and full chest recoil between compressions are equally important components of high-quality CPR.

Question 3: During two-rescuer CPR for an adult patient, what should the compressor do while the ventilator delivers breaths?

Continue compressions without pausing
Pause compressions for 2 seconds (Correct answer)
Switch roles immediately
Check for a pulse

Correct answer: Pause compressions for 2 seconds

In two-rescuer adult CPR, compressions should pause briefly (less than 10 seconds) to allow effective ventilations to be delivered.

During two-rescuer adult CPR with an unprotected airway (no advanced airway), the compressor should pause briefly while the ventilator delivers 2 breaths. This pause should be less than 10 seconds total. Once an advanced airway (e.g., endotracheal tube or supraglottic airway) is placed, continuous compressions at 100-120/min can proceed with asynchronous ventilations at 10 breaths per minute (one breath every 6 seconds) without pausing for breaths.

Question 4: What is the recommended compression rate for adult CPR in the BLS for Healthcare Providers guidelines?

60-80 compressions per minute
80-100 compressions per minute
100-120 compressions per minute (Correct answer)
120-140 compressions per minute

Correct answer: 100-120 compressions per minute

The AHA recommends 100-120 compressions per minute for adult CPR to optimize cardiac output and perfusion pressure.

The 2020 AHA Guidelines recommend a chest compression rate of 100-120 compressions per minute. Rates below 100/min are associated with decreased survival, while rates above 120/min may be associated with inadequate compression depth due to the reduced time available for full compression. A metronome or feedback device can help rescuers maintain the correct rate. Studies show that many rescuers naturally compress too slowly, making this a key quality indicator in BLS training.

Question 5: When should a healthcare provider check for a carotid pulse during the BLS algorithm?

Every 2 minutes during CPR
Before starting CPR if the patient is unresponsive and not breathing normally (Correct answer)
Only after AED shock delivery
Every 5 minutes

Correct answer: Before starting CPR if the patient is unresponsive and not breathing normally

Healthcare providers should check the carotid pulse for no more than 10 seconds if a patient is unresponsive and not breathing normally before beginning CPR.

Healthcare providers are trained to check for a carotid pulse simultaneously with checking for breathing for no more than 10 seconds in an unresponsive patient who is not breathing normally. If no pulse is felt (or if uncertain), CPR should be started immediately. During ongoing CPR, pulse checks are performed every 2 minutes during rhythm analysis pauses. The key principle is to minimize time without compressions—pulse checks during CPR should be brief and only occur when a rhythm check warrants it.

Question 6: What does the term 'high-quality CPR' include according to BLS for Healthcare Providers standards?

Compressions at 60/min, depth 1 inch, full recoil
Rate 100-120/min, depth ≥2 in, full recoil, minimal interruptions, avoid hyperventilation (Correct answer)
Rate 80-100/min, depth 3 inches, no recoil needed
Ventilations every 3 seconds, rate 150/min

Correct answer: Rate 100-120/min, depth ≥2 in, full recoil, minimal interruptions, avoid hyperventilation

High-quality CPR encompasses the correct rate, depth, full chest recoil, minimal interruptions, and avoiding excessive ventilation.

High-quality CPR as defined by the AHA includes: compression rate of 100-120/min, compression depth of at least 2 inches in adults, full chest recoil after each compression, minimizing interruptions (keeping CPR fraction above 60%), and avoiding excessive ventilation (hyperventilation increases intrathoracic pressure and reduces venous return). Real-time feedback devices and team communication are recommended to help rescuers maintain all these components simultaneously during resuscitation.

Question 7: In the BLS healthcare provider algorithm, after delivering a shock with an AED, the rescuer should immediately:

Check the pulse for 10 seconds
Resume CPR starting with chest compressions (Correct answer)
Wait 2 minutes before touching the patient
Deliver a second shock

Correct answer: Resume CPR starting with chest compressions

Immediately after an AED shock, CPR should resume starting with chest compressions without checking the pulse first.

After delivering a shock with an AED, the rescuer should immediately resume CPR starting with chest compressions. A pulse check should not be performed immediately post-shock because it delays compressions and studies show the myocardium needs time to recover perfusion before an organized rhythm can be palpated. The AED will prompt a rhythm analysis after 2 minutes of CPR, at which point the team will pause to allow the device to reassess. Minimizing the peri-shock pause is critical for improving defibrillation success rates.

Question 8: When two rescuers perform CPR on an adult, how often should they switch roles?

Every 1 minute
Every 2 minutes (Correct answer)
Every 5 minutes
Only when one rescuer is fatigued

Correct answer: Every 2 minutes

Rescuers should switch roles every 2 minutes (at each rhythm check) to prevent compressor fatigue and maintain compression quality.

Compressor fatigue leads to shallower compressions and incomplete recoil within as little as 1-2 minutes, even when rescuers report no perceived fatigue. Switching compressors every 2 minutes—coinciding with the AED's rhythm analysis pause—maintains compression quality without adding extra interruptions. Role switching should be practiced so it can be done in under 5 seconds. In hospital settings, the team leader should proactively announce upcoming role switches to ensure smooth transitions.

Question 9: What is the correct hand position for adult chest compressions?

One hand on the upper third of the sternum
Two hands on the lower half of the sternum (Correct answer)
Two hands on the xiphoid process
One hand on the left side of the chest over the heart

Correct answer: Two hands on the lower half of the sternum

Both hands should be placed on the lower half of the sternum (not on the xiphoid process) to deliver effective compressions.

The correct hand position for adult chest compressions is to place the heel of one hand on the lower half of the sternum (center of the chest), then place the other hand on top, interlacing fingers. Rescuers should keep their fingers off the chest wall to focus force on the sternum and avoid rib fractures. The xiphoid process should be avoided as pressure on it can cause liver laceration. Arms should be kept straight and compressions delivered using body weight rather than arm strength alone.

Question 10: For an adult with an advanced airway in place during CPR, ventilations should be delivered at what rate?

Every 3 seconds (20 breaths/min)
Every 6 seconds (10 breaths/min) (Correct answer)
Every 10 seconds (6 breaths/min)
Every 2 seconds (30 breaths/min)

Correct answer: Every 6 seconds (10 breaths/min)

With an advanced airway, give one breath every 6 seconds (10 breaths/min) without pausing compressions.

Once an advanced airway (endotracheal tube, LMA, or other supraglottic device) is in place, compressions should be continuous at 100-120/min while the ventilator delivers one breath every 6 seconds (approximately 10 breaths/min) asynchronously. This eliminates the need for synchronized pauses between breaths and compressions. Each breath should be delivered over 1 second and produce visible chest rise. Hyperventilation must be avoided as it increases intrathoracic pressure, reduces venous return, and decreases cardiac output.

Question 11: What is the preferred method of opening the airway in a patient with no suspected cervical spine injury?

Jaw-thrust maneuver
Head-tilt chin-lift maneuver (Correct answer)
Triple airway maneuver
Neck extension maneuver

Correct answer: Head-tilt chin-lift maneuver

The head-tilt chin-lift is the preferred technique for opening the airway when no spinal injury is suspected.

The head-tilt chin-lift maneuver is performed by placing one hand on the forehead and tilting the head back while lifting the chin with the fingers of the other hand. This extends the neck and lifts the tongue away from the posterior pharynx, opening the airway. It is the preferred technique when cervical spine injury is not a concern. When spinal injury is suspected (e.g., trauma patients), the jaw-thrust maneuver should be used to open the airway without extending the neck, though the head-tilt chin-lift may be used if the jaw-thrust fails to open the airway.

Question 12: Which of the following rhythms is shockable and would prompt AED use?

Asystole
Pulseless electrical activity (PEA)
Ventricular fibrillation (VF) (Correct answer)
Sinus bradycardia

Correct answer: Ventricular fibrillation (VF)

Ventricular fibrillation is a shockable rhythm. The AED is designed to detect and deliver shocks for VF and pulseless ventricular tachycardia.

The two shockable cardiac arrest rhythms are ventricular fibrillation (VF) and pulseless ventricular tachycardia (pVT). In VF, the ventricles quiver chaotically without coordinated contractions, producing no cardiac output. In pVT, there are organized but rapid ventricular complexes with no effective pulse. Both respond to defibrillation, which depolarizes the myocardium simultaneously, allowing the heart's natural pacemaker to resume control. Asystole and PEA are non-shockable rhythms requiring continued CPR and treatment of reversible causes (H's and T's).

Question 13: What is 'chest recoil' and why is it important in CPR?

The sound made during compressions; it confirms correct depth
Allowing the chest to fully return to its natural position after each compression; it allows venous return and cardiac refilling (Correct answer)
The amount of force applied during compressions
The angle of the rescuer's arms during compressions

Correct answer: Allowing the chest to fully return to its natural position after each compression; it allows venous return and cardiac refilling

Full chest recoil allows negative intrathoracic pressure to draw venous blood back to the heart, enabling effective cardiac output.

Chest recoil refers to allowing the chest wall to return fully to its natural position after each compression before the next compression is initiated. This is critical because the negative intrathoracic pressure created during recoil drives venous return to the heart (both right atrium filling and coronary perfusion). Leaning on the chest between compressions—even lightly—impedes this recoil, reduces ventricular filling, and decreases both cardiac output and coronary perfusion pressure. Studies show that incomplete recoil is common even among trained rescuers, making it a key quality metric.

Question 14: In the BLS algorithm, what should be done when the AED indicates 'no shock advised'?

Stop CPR and monitor the patient
Immediately resume CPR starting with chest compressions (Correct answer)
Deliver a manual shock
Check the pulse and call for help

Correct answer: Immediately resume CPR starting with chest compressions

If the AED advises no shock, immediately resume CPR with chest compressions and continue the algorithm.

When the AED indicates 'no shock advised,' the underlying rhythm is either asystole or pulseless electrical activity (PEA)—both non-shockable rhythms. In either case, CPR should be immediately resumed starting with chest compressions. For asystole and PEA, the primary treatment is high-quality CPR combined with identification and treatment of reversible causes (the H's and T's: hypovolemia, hypoxia, hydrogen ion acidosis, hypo/hyperkalemia, hypothermia, tension pneumothorax, tamponade, toxins, thrombosis pulmonary, thrombosis coronary). After 2 more minutes of CPR, the AED will re-analyze.

Question 15: What is the maximum recommended time to pause compressions for any intervention during CPR?

5 seconds
10 seconds (Correct answer)
15 seconds
20 seconds

Correct answer: 10 seconds

Interruptions to chest compressions should not exceed 10 seconds to maintain coronary and cerebral perfusion pressure.

Any interruption to chest compressions—whether for pulse checks, airway management, rhythm analysis, or defibrillation—should not exceed 10 seconds. This is because coronary perfusion pressure (CPP), which is critical for restoring spontaneous circulation, drops precipitously within seconds of stopping compressions and takes many compressions to rebuild. Keeping the chest compression fraction (CCF)—the proportion of resuscitation time during which compressions are being performed—above 60% is associated with improved outcomes. High-performing teams strive for CCF above 80%.

Question 16: Which of the following best describes the 'CPR fraction' or 'chest compression fraction'?

The ratio of ventilations to compressions
The proportion of resuscitation time spent performing chest compressions (Correct answer)
The depth of compressions as a fraction of chest diameter
The number of compressions per breath

Correct answer: The proportion of resuscitation time spent performing chest compressions

CPR fraction (chest compression fraction) is the proportion of total resuscitation time during which chest compressions are being performed; a higher fraction is associated with better outcomes.

The chest compression fraction (CCF), also called CPR fraction, is the proportion of total cardiac arrest resuscitation time during which chest compressions are being delivered. The AHA recommends targeting a CCF of at least 60%, with high-performing teams achieving 80% or higher. A higher CCF means fewer and shorter pauses in compressions, which translates to higher mean coronary perfusion pressure, better myocardial oxygenation, and improved survival rates. Major factors that reduce CCF include prolonged rhythm analysis, lengthy pulse checks, extended ventilation pauses, and delayed defibrillation.

Question 17: During mouth-to-mask ventilation in adult CPR, each breath should be delivered over approximately:

0.5 seconds
1 second (Correct answer)
3 seconds
5 seconds

Correct answer: 1 second

Each rescue breath should be delivered over 1 second, sufficient to produce visible chest rise without causing gastric inflation.

Each rescue breath should be delivered over approximately 1 second, providing just enough tidal volume to produce visible chest rise (approximately 500-600 mL in an average adult). Breaths delivered too quickly or forcefully increase airway pressure, promote gastric insufflation (which risks regurgitation and aspiration), and can cause lung injury. During CPR without an advanced airway, the lower esophageal sphincter tone is reduced, making gastric inflation more likely. Using a pocket mask or bag-valve-mask device provides better seal, filtration, and allows supplemental oxygen delivery.

Question 18: A healthcare provider finds an unresponsive adult. After confirming no normal breathing and no pulse, what is the FIRST action?

Activate the emergency response system (call for help/AED)
Begin chest compressions (Correct answer)
Give 2 rescue breaths
Apply the AED immediately

Correct answer: Begin chest compressions

For a witnessed cardiac arrest with another rescuer present, begin chest compressions immediately while a second rescuer activates EMS and retrieves an AED.

In a witnessed cardiac arrest, if two rescuers are present, one should begin chest compressions immediately while the other activates the emergency response system and retrieves an AED. If alone, the healthcare provider should activate the emergency response system (call for help) and retrieve an AED before beginning CPR for an unwitnessed arrest, but for a witnessed arrest, starting CPR while calling out for someone to call 911 is appropriate. The key principle is minimizing time to first compression and earliest possible defibrillation for shockable rhythms.

Question 19: What does 'ROSC' stand for in the context of advanced cardiac life support and BLS?

Rhythm Of Sinus Contractions
Return Of Spontaneous Circulation (Correct answer)
Rate Of Sustained Compressions
Restoration Of Sinus Capture

Correct answer: Return Of Spontaneous Circulation

ROSC stands for Return of Spontaneous Circulation, indicating the heart has resumed beating effectively on its own.

Return of Spontaneous Circulation (ROSC) is the resumption of a sustained perfusing cardiac rhythm following cardiac arrest. Signs of ROSC include a palpable pulse, a measurable blood pressure, spontaneous breathing, purposeful movement, or improved skin color. When ROSC is achieved, post-resuscitation care becomes the priority—this includes targeted temperature management, hemodynamic optimization, and coronary angiography for suspected cardiac etiology. In BLS, recognition of ROSC (or failure to achieve it) guides decisions about continuing or terminating resuscitation efforts.

Question 20: In BLS for Healthcare Providers, what is the preferred airway management device when bag-valve-mask ventilation is being used?

Nasopharyngeal airway (NPA) only
Oropharyngeal airway (OPA) in unconscious patients without a gag reflex (Correct answer)
Endotracheal tube for all patients
No adjunct needed for BLS

Correct answer: Oropharyngeal airway (OPA) in unconscious patients without a gag reflex

An oropharyngeal airway (OPA) is used in unconscious patients without a gag reflex to maintain airway patency during BVM ventilation.

An oropharyngeal airway (OPA) is inserted in unconscious patients who lack a gag reflex to prevent the tongue from obstructing the posterior pharynx. The correct size is estimated by measuring from the center of the mouth to the earlobe or from the corner of the mouth to the angle of the jaw. A nasopharyngeal airway (NPA) is used in patients with intact gag reflexes or mild-to-moderate altered consciousness. Both adjuncts facilitate bag-valve-mask (BVM) ventilation by maintaining airway patency, improving seal, and reducing the effort required to ventilate effectively.

Question 21: When using a bag-valve-mask (BVM) device with two rescuers, one rescuer should focus on:

Delivering compressions only
Creating a seal with both hands on the mask while the second rescuer squeezes the bag (Correct answer)
Squeezing the bag while monitoring the cardiac monitor
Checking the pulse while ventilating

Correct answer: Creating a seal with both hands on the mask while the second rescuer squeezes the bag

Two-person BVM technique has one rescuer maintain a two-hand mask seal (EC technique) while the second squeezes the bag, ensuring better ventilation.

Two-person BVM technique is significantly more effective than single-person technique. One rescuer uses both hands to maintain a tight mask seal using the 'EC clamp' technique—the thumb and index finger form a 'C' to press down on the mask while the remaining three fingers form an 'E' to lift the jaw. The second rescuer squeezes the bag with both hands. This two-person approach provides a better mask seal, reduces air leak, and allows adequate tidal volume delivery. Studies demonstrate that single-person BVM ventilation is associated with high rates of inadequate ventilation and gastric inflation.

Question 22: What are the H's and T's of cardiac arrest used for in the BLS/ACLS context?

They represent the sequence of AED shocks to deliver
They are reversible causes of cardiac arrest that should be identified and treated (Correct answer)
They describe the correct hand positions for CPR
They are contraindications to starting CPR

Correct answer: They are reversible causes of cardiac arrest that should be identified and treated

The H's and T's are a memory aid for potentially reversible causes of cardiac arrest that can be corrected during resuscitation.

The H's and T's are a mnemonic for the potentially reversible causes of cardiac arrest. The H's include: Hypovolemia, Hypoxia, Hydrogen ion (acidosis), Hypo/Hyperkalemia, and Hypothermia. The T's include: Tension pneumothorax, Tamponade (cardiac), Toxins, Thrombosis pulmonary (PE), and Thrombosis coronary (MI). Identifying and treating these reversible causes is particularly important in PEA and asystole, where defibrillation is ineffective and the primary treatment is CPR plus correction of the underlying cause. A systematic approach to evaluating for these causes should occur concurrently with ongoing resuscitation.

Question 23: What is the recommended epinephrine dose for adult cardiac arrest in the BLS/ACLS context?

0.5 mg IV every 5 minutes
1 mg IV every 3-5 minutes (Correct answer)
2 mg IV once
0.1 mg IV every minute

Correct answer: 1 mg IV every 3-5 minutes

The standard epinephrine dose for adult cardiac arrest is 1 mg IV/IO every 3-5 minutes.

For adult cardiac arrest, epinephrine 1 mg IV or IO (intraosseous) should be administered every 3-5 minutes. For non-shockable rhythms (asystole/PEA), epinephrine should be given as soon as possible. For shockable rhythms (VF/pVT), epinephrine is typically given after the first or second defibrillation attempt. Epinephrine's primary mechanism in cardiac arrest is alpha-1 adrenergic receptor stimulation, causing peripheral vasoconstriction that increases aortic diastolic pressure and improves coronary and cerebral perfusion pressure. Note that while epinephrine improves ROSC rates, its impact on neurologically intact survival remains a topic of ongoing research.

Question 24: Which of the following is a sign of ROSC (Return of Spontaneous Circulation)?

The AED advises 'no shock'
A sudden increase in end-tidal CO2 (ETCO2) to ≥40 mmHg (Correct answer)
The patient remains unresponsive
The heart rate on the monitor is 30 bpm

Correct answer: A sudden increase in end-tidal CO2 (ETCO2) to ≥40 mmHg

A sudden rise in ETCO2 to ≥40 mmHg during CPR strongly suggests ROSC, as improved cardiac output increases CO2 delivery to the lungs.

End-tidal CO2 (ETCO2) monitoring is a valuable tool during resuscitation. During cardiac arrest with CPR, ETCO2 values are typically low (10-20 mmHg) due to reduced pulmonary blood flow. A sudden, sustained rise in ETCO2 to ≥40 mmHg during CPR suggests ROSC because increased cardiac output delivers more CO2 to the lungs for exhalation. ETCO2 is also used to confirm proper endotracheal tube placement, assess CPR quality (low ETCO2 suggests inadequate compressions), and may serve as a prognostic indicator—persistently low ETCO2 despite good CPR quality may predict failure to achieve ROSC.

Question 25: In what situation should a healthcare provider use the jaw-thrust maneuver instead of head-tilt chin-lift?

When the patient is a child
When cervical spine injury is suspected (Correct answer)
When the patient has dentures
When bag-valve-mask ventilation is being used

Correct answer: When cervical spine injury is suspected

The jaw-thrust maneuver is used when cervical spine injury is suspected to avoid neck extension that could worsen a spinal injury.

The jaw-thrust maneuver opens the airway by displacing the mandible anteriorly without extending the neck, making it the preferred technique when cervical spine injury is suspected (e.g., trauma patients, diving accidents, falls from height). It is performed by placing fingers behind the angle of the jaw and lifting anteriorly while the thumbs are on the chin. However, the AHA guidelines acknowledge that if the jaw-thrust does not adequately open the airway, the head-tilt chin-lift may be used even in suspected spinal injury, as airway management takes priority over concerns about potential spinal injury.

Question 26: How should a healthcare provider assess breathing adequacy before starting CPR?

Listen for breath sounds with a stethoscope for 30 seconds
Look for chest rise and listen for breathing for no more than 10 seconds (Correct answer)
Place a mirror in front of the mouth for 20 seconds
Administer a sternal rub and observe the response

Correct answer: Look for chest rise and listen for breathing for no more than 10 seconds

Simultaneously check for breathing and pulse for no more than 10 seconds—look for chest rise and listen/feel for air movement.

Healthcare providers should simultaneously assess for breathing and pulse for no more than 10 seconds. For breathing, look for chest rise and fall and listen/feel for air movement. Agonal gasps (irregular, gasping breaths) should NOT be mistaken for normal breathing—they are a common sign of cardiac arrest. Studies show that dispatchers and bystanders frequently misidentify agonal respirations as normal breathing, delaying CPR initiation. If in doubt about whether breathing is normal, treat the patient as if they are in cardiac arrest and begin CPR.

Question 27: What is the primary purpose of defibrillation in cardiac arrest?

To restart the heart by delivering a sustained electric current
To simultaneously depolarize all myocardial cells, allowing the heart's natural pacemaker to resume (Correct answer)
To increase heart rate in bradycardic patients
To convert PEA to a shockable rhythm

Correct answer: To simultaneously depolarize all myocardial cells, allowing the heart's natural pacemaker to resume

Defibrillation simultaneously depolarizes the myocardium to terminate VF/pVT, allowing the natural pacemaker to potentially resume.

Defibrillation works by delivering a large electrical current that simultaneously depolarizes a critical mass of myocardial cells. This terminates the disorganized, chaotic electrical activity of ventricular fibrillation or pulseless ventricular tachycardia. After the shock, the cardiac conduction system may resume organized electrical activity, potentially restoring an effective perfusing rhythm. Defibrillation does not 'restart' the heart in the common sense—it terminates the abnormal rhythm. Immediate CPR before and after defibrillation is essential to maintain perfusion and maximize the likelihood that the heart will resume an effective rhythm post-shock.

Question 28: What is the correct pediatric (child) compression depth during CPR?

1 inch (2.5 cm)
At least 2 inches (5 cm)
At least one-third the depth of the chest (approximately 2 inches) (Correct answer)
3 inches (7.5 cm)

Correct answer: At least one-third the depth of the chest (approximately 2 inches)

For children (1 year to puberty), compress at least one-third the anteroposterior depth of the chest, approximately 2 inches (5 cm).

For pediatric patients (defined as 1 year of age to puberty), the AHA recommends chest compressions of at least one-third the anteroposterior diameter of the chest, which is approximately 2 inches (5 cm). This proportional approach accounts for the variation in chest sizes among children. For infants (under 1 year), the recommended compression depth is at least one-third the AP diameter, which is approximately 1.5 inches (4 cm). Hand placement for children uses the heel of one hand (two hands for larger children) on the lower half of the sternum, while infants use the two-finger technique or the two-thumb encircling technique.

Question 29: In an infant cardiac arrest, which compression technique is preferred when two healthcare providers are present?

Two-finger technique on the center of the chest
Two-thumb encircling technique (Correct answer)
Heel of one hand technique
Full hand compression

Correct answer: Two-thumb encircling technique

The two-thumb encircling technique is preferred for infant CPR with two rescuers as it generates higher compression depth and coronary perfusion pressure.

When two trained rescuers are present for infant CPR, the two-thumb encircling technique is preferred over the two-finger technique because it generates higher compression depths and better coronary perfusion pressures. In this technique, both thumbs are placed side-by-side or slightly overlapping on the lower half of the sternum (just below the nipple line), while both hands encircle the infant's chest with fingers supporting the back. This technique provides more consistent depth, better recoil, and is less fatiguing than the two-finger technique. The two-finger technique remains acceptable when a single rescuer is present or in premature infants.

Question 30: What does the term 'pulseless electrical activity' (PEA) mean?

The heart has no electrical activity whatsoever
There is organized electrical activity on the monitor but no palpable pulse or adequate cardiac output (Correct answer)
The AED detected a non-shockable rhythm with normal heart rate
Sinus rhythm with very slow rate

Correct answer: There is organized electrical activity on the monitor but no palpable pulse or adequate cardiac output

PEA is organized electrical activity on the cardiac monitor without a detectable pulse, indicating mechanical cardiac failure despite electrical function.

Pulseless electrical activity (PEA) is a clinical state in which organized (or semi-organized) electrical activity is visible on the ECG monitor, but the heart is not generating effective mechanical contractions to produce a palpable pulse or adequate blood pressure. It is a non-shockable rhythm treated with CPR and correction of reversible causes. PEA was formerly called 'electromechanical dissociation' (EMD). Common causes include severe hypovolemia, tension pneumothorax, cardiac tamponade, pulmonary embolism, and severe acidosis—all potentially reversible with appropriate intervention. The prognosis for PEA is generally worse than for VF/VT.

Question 31: When should a healthcare provider consider stopping CPR?

After 10 minutes of unsuccessful resuscitation
After physician direction, Do Not Resuscitate order confirmation, signs of irreversible death, or exhaustion of rescuers (Correct answer)
When the AED advises 'no shock' twice
After 5 rounds of CPR (10 minutes)

Correct answer: After physician direction, Do Not Resuscitate order confirmation, signs of irreversible death, or exhaustion of rescuers

CPR termination decisions should be based on medical direction, DNR status, signs of irreversible death, or physical inability to continue—not on a fixed time limit.

The decision to terminate CPR is complex and should be based on multiple factors: physician direction or medical protocol, confirmed Do Not Resuscitate (DNR) or Do Not Attempt Resuscitation (DNAR) orders, presence of signs of irreversible death (rigor mortis, dependent lividity, decapitation, etc.), prolonged resuscitation without ROSC despite appropriate interventions and exclusion of reversible causes, or physical incapacity of rescuers to continue. In the out-of-hospital setting, termination of resuscitation (TOR) rules help guide EMS providers. No single time threshold universally applies—some patients achieve ROSC after extended resuscitation efforts.

Question 32: What is the recommended tidal volume for bag-valve-mask ventilation during CPR?

1,000-1,200 mL
800-1,000 mL
500-600 mL (enough to produce visible chest rise) (Correct answer)
200-300 mL

Correct answer: 500-600 mL (enough to produce visible chest rise)

Each breath should deliver approximately 500-600 mL (6-7 mL/kg), just enough to produce visible chest rise, avoiding gastric inflation.

The recommended tidal volume for CPR ventilation is 500-600 mL (approximately 6-7 mL/kg of ideal body weight), just sufficient to produce visible chest rise. This is significantly less than the traditional 800-1,000 mL previously recommended. Large tidal volumes increase intrathoracic pressure, reduce venous return, decrease cardiac output, and promote gastric insufflation (increasing aspiration risk). When using a BVM, squeezing only one hand's worth of volume from the bag (rather than a full two-handed squeeze) usually delivers an appropriate tidal volume. Supplemental oxygen should be provided at the highest available concentration during CPR.

Question 33: After ROSC, what is the recommended target for arterial oxygen saturation (SpO2)?

90-94%
94-98% (Correct answer)
100% (maximum)
98-100%

Correct answer: 94-98%

Post-ROSC, target SpO2 of 92-98% (or 94-98%) to avoid both hypoxia and hyperoxia, which are both harmful.

Post-resuscitation care guidelines recommend targeting an SpO2 of 94-98% (some guidelines specify 92-98%) after ROSC to avoid both hypoxemia and hyperoxia. Hyperoxia (excessive oxygen) after cardiac arrest may cause reperfusion injury due to oxygen free radical generation, while hypoxia causes ongoing ischemic damage. FiO2 should be titrated down from 100% as tolerated after ROSC is confirmed. This is part of a broader post-cardiac arrest care bundle that includes targeted temperature management (TTM), hemodynamic optimization targeting a mean arterial pressure ≥65 mmHg, and urgent coronary angiography for suspected STEMI.

Question 34: Which of the following is the correct sequence of the BLS Adult Chain of Survival?

CPR → Activate EMS → AED → Advanced care → Recovery
Recognition and activation → High-quality CPR → Defibrillation → ACLS → Recovery (Correct answer)
AED → CPR → Activate EMS → ACLS → Recovery
Activate EMS → AED → CPR → ACLS → Recovery

Correct answer: Recognition and activation → High-quality CPR → Defibrillation → ACLS → Recovery

The AHA In-Hospital Adult Chain of Survival: Recognition/activation → High-quality CPR → Defibrillation → ACLS → Recovery.

The AHA 2020 Guidelines updated the Adult Chain of Survival to include a 'Recovery' link. The six links in the in-hospital chain are: (1) Surveillance and prevention, (2) Recognition and activation of the emergency response system, (3) High-quality CPR, (4) Defibrillation, (5) Advanced resuscitation (ACLS), and (6) Recovery. For out-of-hospital cardiac arrest, the chain starts with recognition/activation, followed by bystander CPR, AED, EMS advanced care, ACLS, and recovery. The Recovery link acknowledges that survivors need rehabilitation, psychological support, and follow-up care to address long-term effects of cardiac arrest.

Question 35: What is the minimum recommended chest compression fraction (CCF) target during resuscitation?

40%
60% (Correct answer)
80%
95%

Correct answer: 60%

The AHA recommends a minimum CCF of 60%, with high-performing teams targeting 80% or more.

The chest compression fraction (CCF) should be at least 60% of total resuscitation time. This means compressions should be occurring during at least 60% of the time from cardiac arrest recognition to ROSC or termination of resuscitation. Research consistently shows that higher CCF is associated with improved survival and neurological outcomes. The main causes of low CCF include: prolonged pre-shock pauses for rhythm analysis, extended post-shock pulse checks, lengthy ventilation attempts, and delays for procedures. High-performing resuscitation teams routinely achieve CCF >80% through practiced role coordination, real-time feedback, and disciplined protocol adherence.

Question 36: When providing rescue breaths to an adult patient without an advanced airway, each breath should produce:

Audible wheezing
Visible chest rise (Correct answer)
An increase in heart rate on the monitor
A decrease in ETCO2

Correct answer: Visible chest rise

Each rescue breath should produce visible chest rise, confirming adequate ventilation without over-inflation.

The primary indicator of successful ventilation during CPR is visible chest rise. Each rescue breath should cause the chest to visibly rise and fall. If no chest rise is observed, the rescuer should reposition the head to improve airway alignment (head-tilt chin-lift or jaw-thrust), check for a mask seal, consider using an airway adjunct, or look for potential obstructions. A breath that fails to produce chest rise may be going into the stomach (gastric inflation) or may not be entering the lungs at all. Over-inflation (excessive tidal volume) also causes gastric inflation and should be avoided.

CPR BLS for Healthcare Providers 1

What is the recommended compression-to-ventilation ratio for single-rescuer adult CPR in the BLS for Healthcare Providers course?

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