Chain of Survival and Recognition of Arrest / Emergencies
Two chains, one goal
Out-of-hospital cardiac arrest (OHCA) and in-hospital cardiac arrest (IHCA) each have their own chain, and questions test whether you know which link belongs where. The OHCA chain starts with recognition and activation of the emergency response system, then bystander CPR, rapid AED use, advanced resuscitation, post-arrest care, and recovery. The IHCA chain starts with surveillance and prevention - spotting the deteriorating patient before arrest - then rapid response team activation, followed by the same later links. Both chains end with recovery, which is a link, not an afterthought.
Recognition
The first decision saves the most lives: is the patient unresponsive and not breathing normally? Agonal gasps are common in the first minutes of arrest and are frequently mistaken for adequate breathing. An unresponsive patient with only gasping needs CPR now. Palpate a carotid pulse for no more than 10 seconds; if you are not certain a pulse is present, begin compressions. Waiting for certainty is a classic distractor.
Traps
Watch for answers that delay compressions: "complete the assessment," "obtain a full history," "wait for the code team," or "give two rescue breaths first." Also watch for reversed links, such as defibrillating before starting CPR in a lone-rescuer situation without an AED at hand, or a lone rescuer with no phone who calls instead of starting CPR.
Rule of thumb
Unresponsive plus not breathing normally equals start compressions. A lone rescuer with a mobile phone calls first, then does CPR; a lone rescuer without a phone does 2 minutes of CPR, then leaves to call.