BLS — Basic Life Support — All Questions
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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.