Quick Reference Guide: Basic Life Support

C-A-B Sequence (All Ages)

1. C – Compressions

   • Rate: 100–120/min

   • Depth:

     • Adults: At least 2 inches (5 cm)

     • Children: ~2 inches (5 cm)

     • Infants: 1.5 inches (4 cm)

   • Allow for full chest recoil

   • Minimize interruptions (<10 seconds)

2. A – Airway

   • Head tilt–chin lift (unless trauma suspected)

   • Jaw thrust if spinal injury suspected

3. B – Breathing

   • Give 2 breaths (1 sec each) after every 30 compressions (1 or 2 rescuers)

   • Watch for visible chest rise

   • 
     

Compression-to-Breath Ratios

VICTIM	1 RESCUER	2 RESCUERS
Adult	30:2	30:2
Child	30:2	15:2
Infant	30:2	15:2