From USPS News Link:
Anaheim, CA, Letter Carrier Thoai Le was on his route when he saw a man performing CPR on another man and ran over to help. Le called 911, then performed chest compressions on the victim while the other man spoke to the 911 operator, who provided instructions on what to do until help arrived. The ill man was taken to a hospital, where he recovered. Le, the other good Samaritan and the emergency responders where later recognized by the city for their efforts.