BLS — Basic Life Support — All Questions

At what rate should chest compressions be delivered to an adult in cardiac arrest?

• a.60 to 80 compressions per minute
• b.80 to 100 compressions per minute
• c.100 to 120 compressions per minute✓
• d.At least 140 compressions per minute

Current AHA guidelines specify a compression rate of 100 to 120 per minute for all ages. Slower than 100 does not generate adequate perfusion, while faster than 120 shortens the recoil phase so the heart cannot refill, which paradoxically lowers the blood delivered per compression.

What is the correct compression depth for an adult victim?

• a.At least 1 inch (2.5 cm)
• b.At least 2 inches (5 cm) but no more than 2.4 inches (6 cm)✓
• c.At least 3 inches (7.5 cm)
• d.As deep as possible with each compression

Adult compressions should be at least 2 inches (5 cm) and not exceed 2.4 inches (6 cm). Depth less than 2 inches fails to move enough blood, while excessive depth beyond 2.4 inches increases the risk of injury to the chest and underlying organs without added benefit.

What is the correct compression depth for an infant (under 1 year)?

• a.About 0.5 inch (1 cm)
• b.About 1 inch (2.5 cm)
• c.About 1.5 inches (4 cm), or one-third the depth of the chest✓
• d.At least 2.4 inches (6 cm)

Compress an infant's chest at least one-third of its anterior-posterior diameter, which is about 1.5 inches (4 cm). For a child it is about one-third the depth, roughly 2 inches (5 cm). Compressing to a fixed fraction of chest depth scales the force appropriately to the small size of the pediatric chest.

To maximize blood flow during CPR, rescuers should allow complete chest recoil and aim for a chest compression fraction of at least:

• a.30%
• b.40%
• c.50%
• d.60%✓

Chest compression fraction — the proportion of arrest time spent actively compressing — should be at least 60%. Allowing full recoil between compressions lets the heart refill, and minimizing pauses (keeping any interruption under 10 seconds) preserves the coronary and cerebral perfusion that compressions build up.

An AED arrives while you are performing CPR on an adult in cardiac arrest. What should you do?

• a.Finish 5 more minutes of CPR before using the AED
• b.Turn on the AED, attach the pads, and follow its prompts while minimizing interruptions in compressions✓
• c.Check for a pulse for a full minute before attaching the AED
• d.Only use the AED if a physician is present to authorize it

Early defibrillation is time-critical for shockable rhythms, so as soon as an AED is available you turn it on, attach the pads, and follow the voice prompts. Compressions continue until the AED is ready to analyze, keeping the interruption as short as possible. No physician authorization is required to use an AED.

You are using an AED on a 5-year-old child. Which is correct?

• a.Use pediatric pads or a pediatric dose attenuator if available✓
• b.Never use an AED on a child under 8 years old
• c.Always use adult pads at full energy regardless of availability
• d.Delay defibrillation until EMS brings a pediatric AED

For a child under 8 years, use pediatric pads or a dose attenuator if they are available to reduce the delivered energy. However, if only adult pads are available, use them rather than withhold a needed shock — just ensure the pads do not touch each other. Defibrillation should never be delayed for a shockable rhythm.

Immediately after the AED delivers a shock to an adult, the rescuer should:

• a.Check for a pulse for 10 seconds before doing anything else
• b.Wait for the AED to re-analyze before touching the victim
• c.Resume chest compressions immediately, starting with compressions✓
• d.Give 2 rescue breaths and then reassess the airway

After any shock — or after a 'no shock advised' message — resume high-quality chest compressions immediately without pausing to check a pulse. The heart needs perfusion to recover an effective rhythm, and the next rhythm/pulse analysis occurs after the full 2-minute CPR cycle. Stopping to check a pulse wastes critical perfusion time.

Before the AED analyzes the rhythm and before delivering a shock, the rescuer must:

• a.Pour water on the chest to improve pad conduction
• b.Place both pads on the same side of the chest
• c.Remove the victim's clothing but leave medication patches in place
• d.Ensure no one is touching the victim and clearly state 'Clear'✓

Everyone must be clear of the victim during analysis and shock so the reading is accurate and no rescuer is shocked; announce 'Clear' and visually confirm no contact. The chest should be dry (not wet), pads are placed in the diagonal positions shown, and any transdermal medication patch is removed and the area wiped so it does not block energy or cause a burn.

Which best describes 'closed-loop communication' during a resuscitation?

• a.The team leader gives orders that no one is allowed to question
• b.The receiver confirms and repeats back the order, then reports when the task is complete✓
• c.Team members communicate only in writing to avoid noise
• d.Only the physician is permitted to speak during the code

Closed-loop communication means the leader gives a clear order, the receiver acknowledges and repeats it back, and then reports completion. This loop confirms the message was heard correctly and prevents tasks from being missed or duplicated — a core BLS team-dynamics behavior that keeps the resuscitation organized.

During a prolonged resuscitation, how often should the compressor be rotated to maintain high-quality compressions?

• a.Only when the compressor says they are exhausted
• b.Every 10 minutes
• c.About every 2 minutes (every 5 cycles), switching in under 5 seconds✓
• d.Never — changing compressors interrupts CPR too much

Rescuer fatigue causes compression depth and rate to decline, often before the rescuer notices. Rotating compressors about every 2 minutes — ideally during a rhythm check — keeps compressions high-quality. The switch should take less than 5 seconds to minimize the interruption in blood flow.

A team member notices the compressor's rate has slowed below 100 per minute. What is the appropriate action?

• a.Speak up promptly with constructive intervention about the rate✓
• b.Say nothing because correcting a peer is disrespectful
• c.Wait until the code is over to mention it privately
• d.Take over compressions without any communication

Constructive intervention — respectfully speaking up when you observe a problem such as a slowing rate or shallow depth — is an expected team behavior that protects CPR quality. It is directed at the action, not the person. Staying silent to avoid awkwardness allows low-quality CPR to continue, which harms the patient.

How should each rescue breath be delivered?

• a.As forcefully and quickly as possible to guarantee air entry
• b.Over about 1 second, giving just enough volume to make the chest visibly rise✓
• c.Over 5 seconds with maximum volume to fully inflate the lungs
• d.Only through the nose while holding the mouth closed

Each breath is given over about 1 second with only enough volume to produce a visible chest rise. Excessive volume or force causes gastric inflation and vomiting and raises intrathoracic pressure, which reduces venous return and cardiac output — so more air is actively harmful, not helpful.

A single rescuer is performing CPR on an adult without an advanced airway. What compression-to-ventilation ratio is used?

• a.30 compressions to 2 breaths✓
• b.15 compressions to 2 breaths
• c.5 compressions to 1 breath
• d.Continuous compressions with no breaths

A lone rescuer uses a 30:2 ratio for adults, children, and infants. The 15:2 ratio applies only when two rescuers are caring for a child or infant. Once an advanced airway is in place, rescuers switch to continuous compressions with one breath every 6 seconds and stop pausing for breaths.

An adult has a pulse but is not breathing. What is the correct rescue-breathing rate?

• a.1 breath every 2 seconds (about 30 per minute)
• b.1 breath every 10 seconds (about 6 per minute)
• c.1 breath every 6 seconds (about 10 per minute)✓
• d.1 breath every 3 seconds (about 20 per minute)

When an adult has a pulse but inadequate breathing, give rescue breaths at 1 every 6 seconds, about 10 per minute, without chest compressions. Recheck the pulse roughly every 2 minutes. If the pulse is lost, begin CPR with compressions.

A child has a pulse but is not breathing adequately. What is the correct rescue-breathing rate?

• a.1 breath every 6 seconds (about 10 per minute)
• b.1 breath every 10 seconds (about 6 per minute)
• c.1 breath every 15 seconds (about 4 per minute)
• d.1 breath every 2 to 3 seconds (about 20 to 30 per minute)✓

For an infant or child with a pulse but inadequate breathing, give 1 breath every 2 to 3 seconds, about 20 to 30 per minute — faster than the adult rate of 1 every 6 seconds because children have a higher metabolic and oxygen demand. If the heart rate falls below 60 per minute with signs of poor perfusion, start chest compressions.

A responsive adult clutches his throat, cannot speak or cough, and is turning blue. What should you do?

• a.Encourage him to keep coughing and do nothing else
• b.Give abdominal thrusts until the object is expelled or he becomes unresponsive✓
• c.Give 2 rescue breaths immediately
• d.Perform a blind finger sweep of the mouth

Inability to speak or cough with cyanosis signals a severe airway obstruction. For a responsive adult or child, deliver abdominal thrusts (the Heimlich maneuver) until the object comes out or the victim becomes unresponsive. A blind finger sweep can push the object deeper and is not recommended.

A 6-month-old infant is choking, cannot cry, and is in obvious distress. The correct technique is:

• a.Abdominal thrusts (Heimlich maneuver)
• b.A blind finger sweep followed by rescue breaths
• c.Cycles of 5 back slaps followed by 5 chest thrusts✓
• d.Holding the infant upside down and shaking

For a choking responsive infant, deliver cycles of 5 back slaps followed by 5 chest thrusts, supporting the head and neck. Abdominal thrusts are not used on infants because they can injure the liver and other abdominal organs. Repeat the cycles until the object is expelled or the infant becomes unresponsive.

A choking victim you were treating suddenly becomes unresponsive. What should you do next?

• a.Lower them to the ground, activate emergency response, and begin CPR starting with compressions✓
• b.Continue abdominal thrusts on the ground until help arrives
• c.Give 5 rescue breaths before doing anything else
• d.Perform repeated blind finger sweeps until the object is found

When a choking victim becomes unresponsive, lower them safely to the ground, activate the emergency response system, and begin CPR starting with chest compressions. Each time you open the airway to give breaths, look inside the mouth and remove the object only if you can see it — the compressions themselves also help generate pressure to expel the obstruction.

An adult is coughing forcefully and can still speak while eating. This indicates:

• a.A severe obstruction requiring immediate abdominal thrusts
• b.A cardiac arrest requiring CPR
• c.A need for immediate back slaps
• d.A mild obstruction — encourage continued coughing and do not interfere✓

Forceful coughing and the ability to speak indicate a mild (partial) obstruction with good air exchange. A strong cough moves more air than any manual maneuver, so you should encourage continued coughing, stay with the victim, and be ready to act only if the obstruction becomes severe (silent cough, inability to speak or breathe).

What is the first link in the out-of-hospital adult Chain of Survival?

• a.Advanced life support by paramedics
• b.Recognition of the arrest and activation of the emergency response system✓
• c.Post-cardiac-arrest care in the ICU
• d.Defibrillation with an AED

The out-of-hospital chain begins with recognizing that the person is in cardiac arrest and activating the emergency response system (calling 911 and sending someone for an AED). Only after recognition and activation can the following links — immediate high-quality CPR, rapid defibrillation, advanced care, and post-arrest care — proceed.

How does the in-hospital Chain of Survival differ from the out-of-hospital chain at its start?

• a.It begins with post-arrest care rather than CPR
• b.It has no role for defibrillation
• c.It begins with surveillance and prevention to recognize deterioration and prevent arrest✓
• d.It skips activation of a response team

The in-hospital chain starts with surveillance and prevention — monitoring patients and recognizing deterioration early to prevent the arrest from happening — followed by activation of the rapid response or code team. Hospitalized patients are continuously monitored and surrounded by professionals, whereas out-of-hospital victims depend on bystanders and EMS.

Why is early defibrillation such a critical link in the Chain of Survival for a shockable rhythm?

• a.For every minute defibrillation is delayed, the chance of survival falls by roughly 7 to 10 percent✓
• b.Defibrillation is only useful after 20 minutes of CPR
• c.Defibrillation replaces the need for chest compressions entirely
• d.Early defibrillation matters only in the hospital setting

For ventricular fibrillation or pulseless ventricular tachycardia, defibrillation is the definitive treatment, and survival drops by approximately 7 to 10 percent for each minute it is delayed without CPR. This is why getting an AED on the chest quickly, combined with immediate high-quality CPR, is a priority for the BLS provider.