You are the triage officer at the scene of a mass casualty incident. Which of the following patients should be treated first?

A. A 37-year-old female patient who is unresponsive
B. An 18-year-old male patient who is not breathing and has no pulse
C. A 29-year-old male patient with a femur fracture
D. An 8-year-old patient who is conscious but is having trouble breathing

Answer: A. A 37-year-old female patient who is unresponsive