TheoryBLS Study Guide
Study for the BLS with exam topics, practice questions, a free PDF, video walkthrough and timed mock exam links.
How to study for BLS
- Read the topic list so you know what the exam is likely to cover.
- Answer the free practice questions and read every explanation.
- Download the PDF for offline review.
- Use timed mock exams when your untimed practice feels comfortable.
Topics to review
- Safe and effective care environment
- Health promotion and maintenance
- Psychosocial and physiological integrity
- Pharmacology, infection control and patient safety
Try BLS questions now
Q1You arrive at a scene where a person is lying motionless on the floor. What is the FIRST action you should take before approaching?
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✓ Correct answer: Ensure the scene is safe for you to approach
Scene safety is the first priority in any emergency response — a rescuer who becomes a victim cannot help anyone, so you must ensure the environment is safe before approaching.
Q2When performing adult CPR as a lone rescuer, what is the correct compression-to-ventilation ratio?
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✓ Correct answer: 30:2
The AHA BLS standard for a lone rescuer performing adult CPR is 30 compressions followed by 2 ventilations, regardless of whether an advanced airway is in place.
Q3A colleague collapses at work. After confirming the scene is safe, you tap the person's shoulders firmly and shout. There is no response. What should you do NEXT?
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✓ Correct answer: Simultaneously check for breathing and a carotid pulse for no more than 10 seconds
After confirming unresponsiveness, the AHA BLS protocol directs you to simultaneously check for breathing and a carotid pulse for no more than 10 seconds before deciding on the next action.
Q4During adult CPR, your partner notes that the patient's chest is not fully returning to its resting position between compressions. What is the MOST likely consequence of this finding?
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✓ Correct answer: Venous return to the heart will be reduced, lowering cardiac output
Incomplete chest recoil (leaning on the chest) elevates intrathoracic pressure and impairs venous return, which decreases cardiac output and reduces the effectiveness of CPR.
Q5You are performing solo CPR on an adult. After your first set of 30 compressions, you deliver 2 rescue breaths, each taking about 1 second. Approximately how long should both rescue breaths take in total before you resume compressions?
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✓ Correct answer: About 2 seconds combined
Each breath should be delivered over 1 second with visible chest rise, meaning both breaths together take approximately 2 seconds, minimizing interruptions to compressions.
Q6A bystander CPR team has been performing compressions for nearly 2 minutes. According to AHA BLS guidelines, what should they do at this point regarding the compressor role?
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✓ Correct answer: Switch compressors every 2 minutes or 5 cycles to prevent fatigue-related quality decline
The AHA recommends switching compressors approximately every 2 minutes (or every 5 cycles of 30:2) because rescuer fatigue quickly degrades compression depth and rate, reducing CPR quality.
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