A choking person's airway may be completely or partially blocked, so that not enough oxygen reaches the lungs. A complete blockage is a medical emergency. A partial blockage can quickly become life threatening if the person cannot properly breathe in and out.

Without oxygen, permanent brain damage can occur in as little as 4 - 6 minutes. Rapid first aid for choking can save a life.

Occasionally an object will enter the lung. While the person may appear to improve and breathe normally, in a few days symptoms may develop, such as:

• Persistent cough
• Pneumonia
• Wheezing

• Eating too fast, failing to chew food well enough, or eating with improperly fitted dentures
• Drinking alcohol (even a small amount of alcohol affects awareness)
• Being unconscious and breathing in vomited material
• Breathing in small objects (young children)
• Trauma to the head and face (swelling, blood, or a deformity can cause choking)

The universal distress signal for choking is grabbing the throat with the hand.

Other danger signs include:

• Bluish skin color
• Difficulty breathing
• Inability to speak
• Loss of consciousness if blockage is not cleared
• Noisy breathing or high-pitched sounds while inhaling
• Weak, ineffective coughing

How to perform the Heimlich maneuver:

1. First ask, "Are you choking? Can you speak?" DO NOT perform first aid if the person is coughing forcefully and able to speak -- a strong cough can dislodge the object.
2. Stand behind the person and wrap your arms around the person's waist.
3. Make a fist with one hand. Place the thumb side of your fist just above the person's navel, well below the breastbone.
4. Grasp the fist with your other hand.
5. Make quick, upward and inward thrusts with your fist.
6. Continue these thrusts until the object is dislodged or the victim loses consciousness.

IF THE PERSON LOSES CONSCIOUSNESS

• Lower the person to the floor.
• Call 911 -- or tell someone to call 911.
• Begin CPR.
• If you see something blocking the airway, try to remove it.

FOR PREGNANT OR OBESE PEOPLE

1. Wrap your arms around the person's CHEST.
2. Place your fist on the MIDDLE of the breastbone between the nipples.
3. Make firm, backward thrusts.

After removing the object that caused the choking, keep the person still and get medical help. Anyone who is choking should have a medical examination. Complications can occur not only from the choking, but also from the first aid measures that were taken.

• DO NOT interfere if the person is coughing forcefully, able to speak, or is able to breathe in and out adequately. However, be ready to act immediately if the person's symptoms worsen.
• DO NOT try to grasp and pull out the object if the person is conscious.

Seek medical help right away if you find someone unconscious.

When the person is choking:

• Tell someone to call 911 or the local emergency number while you begin first aid/CPR.
• If you are alone, shout for help and begin first aid/CPR.

After the object is successfully dislodged, the person should see a doctor because complications can arise.

In the days following a choking episode, contact a doctor immediately if the person develops:

• Persistent cough
• Pneumonia
• Wheezing

These could be signs that the object entered the lung instead of being expelled.

• Eat slowly and chew food thoroughly.
• Make sure dentures fit properly.
• Don't drink too much alcohol before or during eating.
• Keep small objects away from young children.

Manno M. Pediatric respiatory emergencies: upper airway obstruction and infections. In: Marx J, ed. Rosen's Emergency Medicine: Concepts and Clinical Practice. 6th ed. Philadelphia, Pa: Mosby Elsevier; 2006: chap 166.

Thomas SH, Brown DFM. Foreign bodies. In: Marx J, ed. Rosen's Emergency Medicine: Concepts and Clinical Practice. 6th ed. Philadelphia, Pa: Mosby Elsevier; 2006: chap 57.