If EMS witnesses a patient in cardiac arrest with no pulse, what is the initial action?

• A. Wait for AED
• B. Begin chest compressions at 30:2 until the airway is placed
• C. Check pulse for 10 seconds
• D. Administer epinephrine first

Answer: (B)

Immediate high-quality chest compressions are essential when you witness someone in cardiac arrest with no pulse. The goal is to restore perfusion as quickly as possible because every second without circulation reduces brain and heart viability. For a single rescuer, you start CPR with a 30 compressions to 2 breaths cycle, keeping the rate around 100–120 compressions per minute and the depth about 2 inches (5 cm). Continuing this pattern until you can place an airway ensures that perfusion isn’t interrupted while you manage the airway. Once the airway is secured, you can shift to continuous chest compressions with breaths delivered as per protocol. Quick defibrillation with an AED should be done as soon as it’s available, and you don’t delay CPR or ventillation to check for a pulse or to administer medications first.