ACLS MidTerm Exam | Complete Practice Questions, Correct
Answers & Detailed Rationales (2026/2027)
Question 1
What is the primary and most critical intervention for survival in a
patient who experiences a witnessed sudden cardiac arrest due to
ventricular fibrillation (VF)?
• A. Immediate placement of an advanced airway
• B. Administration of high-dose intravenous vasopressin
• C. Early defibrillation combined with high-quality chest
compressions
• D. Rapid establishment of central venous access
Correct Answer: C. Early defibrillation combined with high-quality chest
compressions
Detailed Rationale: In witnessed sudden cardiac arrest due to VF or
pulseless ventricular tachycardia (pVT), the rhythm is typically
shockable. High-quality chest compressions combined with early
defibrillation provide the highest likelihood of restoring a perfusing
rhythm and ensuring neurological survival.
Question 2
During single-provider adult CPR when no advanced airway is in place,
what is the recommended compression-to-ventilation ratio?
• A. 15:2
, • B. 30:2
• C. 5:1
• D. 10:1
Correct Answer: B. 30:2
Detailed Rationale: For single-provider adult basic life support and CPR
without an advanced airway, the compression-to-ventilation ratio is 30
compressions to 2 rescue breaths. This ratio optimizes blood flow while
delivering adequate oxygenation.
Question 3
What is the recommended rate for chest compressions during adult
cardiopulmonary resuscitation (CPR)?
• A. 60 to 80 compressions per minute
• B. 80 to 100 compressions per minute
• C. 100 to 120 compressions per minute
• D. 120 to 140 compressions per minute
Correct Answer: C. 100 to 120 compressions per minute
Detailed Rationale: High-quality CPR mandates a compression rate of
100 to 120 compressions per minute. Rates below 100 are insufficient
to maintain cardiac output, while rates above 120 reduce compression
depth and venous return.
Question 4
What is the minimum recommended depth for chest compressions in
an average adult during high-quality CPR?
, • A. At least 1.5 inches (4 cm)
• B. At least 2 inches (5 cm)
• C. Exactly 3 inches (7.5 cm)
• D. 1 inch (2.5 cm)
Correct Answer: B. At least 2 inches (5 cm)
Detailed Rationale: High-quality adult CPR requires chest compressions
of at least 2 inches (5 cm) to effectively squeeze the heart between the
sternum and spine, generating adequate systemic blood flow, but not
exceeding 2.4 inches (6 cm) to minimize injury.
Question 5
Why is complete chest recoil between compressions critical during CPR?
• A. It prevents rib fractures and flail chest.
• B. It allows the heart to refill with blood between compressions.
• C. It prevents hyperventilation-induced alkalosis.
• D. It ensures synchronization with rescue breaths.
Correct Answer: B. It allows the heart to refill with blood between
compressions.
Detailed Rationale: Allowing complete chest recoil lets the heart
chambers expand and fill with venous blood (preload) during diastole.
Leaning on the chest increases intrathoracic pressure and significantly
reduces cardiac output.
Question 6
, What is the maximum recommended duration for interrupting chest
compressions to check a pulse, analyze a rhythm, or perform other
tasks?
• A. 5 seconds or less
• B. 10 seconds or less
• C. 20 seconds or less
• D. 30 seconds or less
Correct Answer: B. 10 seconds or less
Detailed Rationale: Interruptions in chest compressions cause coronary
perfusion pressure and cerebral blood flow to drop precipitously.
Providers must limit all chest compression interruptions to 10 seconds
or less.
Question 7
What is the correct ventilation rate when an advanced airway (such as
an endotracheal tube or supraglottic airway) is in place during adult
cardiac arrest?
• A. 1 breath every 2 to 3 seconds (20-30 breaths/min)
• B. 1 breath every 6 seconds (10 breaths/min)
• C. 1 breath every 10 seconds (6 breaths/min)
• D. Synchronized 2 breaths every 30 compressions
Correct Answer: B. 1 breath every 6 seconds (10 breaths/min)
Detailed Rationale: Once an advanced airway is established,
compressions are delivered continuously without pauses, and rescue
Answers & Detailed Rationales (2026/2027)
Question 1
What is the primary and most critical intervention for survival in a
patient who experiences a witnessed sudden cardiac arrest due to
ventricular fibrillation (VF)?
• A. Immediate placement of an advanced airway
• B. Administration of high-dose intravenous vasopressin
• C. Early defibrillation combined with high-quality chest
compressions
• D. Rapid establishment of central venous access
Correct Answer: C. Early defibrillation combined with high-quality chest
compressions
Detailed Rationale: In witnessed sudden cardiac arrest due to VF or
pulseless ventricular tachycardia (pVT), the rhythm is typically
shockable. High-quality chest compressions combined with early
defibrillation provide the highest likelihood of restoring a perfusing
rhythm and ensuring neurological survival.
Question 2
During single-provider adult CPR when no advanced airway is in place,
what is the recommended compression-to-ventilation ratio?
• A. 15:2
, • B. 30:2
• C. 5:1
• D. 10:1
Correct Answer: B. 30:2
Detailed Rationale: For single-provider adult basic life support and CPR
without an advanced airway, the compression-to-ventilation ratio is 30
compressions to 2 rescue breaths. This ratio optimizes blood flow while
delivering adequate oxygenation.
Question 3
What is the recommended rate for chest compressions during adult
cardiopulmonary resuscitation (CPR)?
• A. 60 to 80 compressions per minute
• B. 80 to 100 compressions per minute
• C. 100 to 120 compressions per minute
• D. 120 to 140 compressions per minute
Correct Answer: C. 100 to 120 compressions per minute
Detailed Rationale: High-quality CPR mandates a compression rate of
100 to 120 compressions per minute. Rates below 100 are insufficient
to maintain cardiac output, while rates above 120 reduce compression
depth and venous return.
Question 4
What is the minimum recommended depth for chest compressions in
an average adult during high-quality CPR?
, • A. At least 1.5 inches (4 cm)
• B. At least 2 inches (5 cm)
• C. Exactly 3 inches (7.5 cm)
• D. 1 inch (2.5 cm)
Correct Answer: B. At least 2 inches (5 cm)
Detailed Rationale: High-quality adult CPR requires chest compressions
of at least 2 inches (5 cm) to effectively squeeze the heart between the
sternum and spine, generating adequate systemic blood flow, but not
exceeding 2.4 inches (6 cm) to minimize injury.
Question 5
Why is complete chest recoil between compressions critical during CPR?
• A. It prevents rib fractures and flail chest.
• B. It allows the heart to refill with blood between compressions.
• C. It prevents hyperventilation-induced alkalosis.
• D. It ensures synchronization with rescue breaths.
Correct Answer: B. It allows the heart to refill with blood between
compressions.
Detailed Rationale: Allowing complete chest recoil lets the heart
chambers expand and fill with venous blood (preload) during diastole.
Leaning on the chest increases intrathoracic pressure and significantly
reduces cardiac output.
Question 6
, What is the maximum recommended duration for interrupting chest
compressions to check a pulse, analyze a rhythm, or perform other
tasks?
• A. 5 seconds or less
• B. 10 seconds or less
• C. 20 seconds or less
• D. 30 seconds or less
Correct Answer: B. 10 seconds or less
Detailed Rationale: Interruptions in chest compressions cause coronary
perfusion pressure and cerebral blood flow to drop precipitously.
Providers must limit all chest compression interruptions to 10 seconds
or less.
Question 7
What is the correct ventilation rate when an advanced airway (such as
an endotracheal tube or supraglottic airway) is in place during adult
cardiac arrest?
• A. 1 breath every 2 to 3 seconds (20-30 breaths/min)
• B. 1 breath every 6 seconds (10 breaths/min)
• C. 1 breath every 10 seconds (6 breaths/min)
• D. Synchronized 2 breaths every 30 compressions
Correct Answer: B. 1 breath every 6 seconds (10 breaths/min)
Detailed Rationale: Once an advanced airway is established,
compressions are delivered continuously without pauses, and rescue
