When an emergency happens, you should always call 911 for assistance. But what if you’re in an area not quickly reached by first responders or you’re caught in a rapidly changing emergency? You may need to rely on your own skills to save a life before help arrives.

The immediate threats to life— those requiring a virtually instant response from bystanders—are actually few in number: the obstructed airway, the person without a pulse or with uncontrolled bleeding.

In all situations, ensure your own safety first, says Dr. Ben Williams, medical director of the Emergency Department at NorthBay Medical Center and NorthBay VacaValley Hospital. Then turn your attention to the ill or injured person and apply the ABCs of emergency care: Airway, Breathing and Circulation.

“If you have managed to reach a 911 operator, stay on the line and follow instructions,” Dr. Williams said. Is the person breathing or is his airway blocked? A person who can speak clearly is usually breathing through a normal airway. If the person has collapsed and is not breathing, it is time to perform cardiopulmonary resuscitation (CPR, see page 8) to maintain circulation.

When the person is breathing, your next concern is to control bleeding. If there is excessive bleeding, first apply direct pressure to the wound to contain the loss of blood. If you are unable to control the bleeding on an arm or leg with direct pressure, apply a tourniquet above the wound. Tourniquets can be used safely and will not cause irreversible damage if left on for less than one to two hours, according to Dr. Williams. When first responders arrive, they will evaluate the need for a tourniquet.

Learn basic CPR and complete a first aid class to arm yourself with the skills you need should you be called upon to help in an emergency situation.

Although usually not life-threating, a broken bone is disabling and the victim needs help. “If a bone is broken, don’t move it or try to splint it. It is best left for first responders,” Dr. Williams advised. “If you suspect a neck injury, don’t move the patient.”

If you come across a car accident, do not attempt to extricate people from the car unless they are in immediate danger of fire or flood. “Learning basic CPR and completing a first aid class will arm you with the skills you need should the unexpected happen and you are called upon to help,” Dr. Williams added.