吃东西时突然大块食物呛入气管，怎么办？打电话等救护车吗？

Every year about 3,000 adults die because they accidentally inhale rather than swallow food. The food gets stuck and blocks their trachea, making breathing impossible. Death follows rapidly unless the food or other foreign material can be displaced from the airway.Oxygen deprivation from a foreign body airway obstruction can result in permanent brain damage or death in four minutes or less.
每年有3000例成年人因为食物误入气管而意外死亡。食物或者其他异物卡在气管内，如果不迅速取出，呼吸即被阻断。由此造成的组织缺氧在4分钟内即可造成不可逆性的脑损伤并可导致死亡。


In 1974 Dr. Henry Heimlich first described an emergency technique for expelling foreign material blocking the trachea. This technique, now called the Heimlich maneuver or abdominal thrusts, is simple enough that it can be performed immediately by anyone trained in the maneuver. The Heimlich maneuver is a standard part of all first aid courses.The theory behind the Heimlich maneuver is that by compressing the abdomen below the level of the diaphragm, air is forced under pressure out of the lungs dislodging the obstruction in the trachea and bringing the foreign material back up into the mouth.The Heimlich maneuver is used mainly when solid material like food, coins, vomit, or small toys are blocking the airway. There has been some controversy about whether the Heimlich maneuver is appropriate to use routinely on near-drowning victims. After several studies of the effectiveness of the Heimlich maneuver on reestablishing breathing in near-drowning victims, the American Red Cross and the American Heart Association both recommend that the Heimlich maneuver be used only as a last resort after traditional airway clearance techniques and cardiopulmonary resuscitation (CPR) have been tried repeatedly and failed or if it is clear that a solid foreign object is blocking the airway.海姆里克急救法，1974年由Dr. Henry Heimlich这个人首先报道。注意，不是所有的气管阻塞都可以使用这个急救法。

Precautions
Incorrect application of the Heimlich maneuver can damage the chest, ribs, and internal organs of the person on whom it is performed. People may also vomit after being treated with the Heimlich maneuver. 使用不当可以造成局部组织的损伤。
Description
The Heimlich maneuver can be performed on all people. Modifications are necessary if the choking victim is very obese, pregnant, a child, or an infant.
气管阻塞的指征：
急迫的抓、挠咽喉部；
无法说话、喊叫或者呼吸；
面部和口唇粘膜变青紫；
呼吸困难、费力并发出高调哨鸣音；
以上这些之后就是昏迷。
Indications that a person's airway is blocked include:
• The person can not speak or cry out.
• The person's face turns blue from lack of oxygen.
• The person desperately grabs at his or her throat.
• The person has a weak cough, and labored breathing produces a high-pitched noise.
• The person does all of the above, then becomes unconscious.
Performing the Heimlich maneuver on adults
如何操作：

To perform the Heimlich maneuver on a conscious adult, the rescuer stands behind the victim. The victim may either be sitting or standing. The rescuer makes a fist with one hand, and places it, thumb toward the victim, below the rib cage and above the waist. The rescuer encircles the victim's waist, placing his other hand on top of the fist.In a series of 6–10 sharp and distinct thrusts upward and inward, the rescuer attempts to develop enough pressure to force the foreign object back up the trachea. If the maneuver fails, it is repeated. It is important not to give up if the first attempt fails. As the victim is deprived of oxygen, the muscles of the trachea relax slightly. Because of this loosening, it is possible that the foreign object may be expelled on a second or third attempt.If the victim is unconscious, the rescuer should lay him or her on the floor, bend the chin forward, make sure the tongue is not blocking the airway, and feel in the mouth for foreign objects, being careful not to push any farther into the airway. The rescuer kneels astride the victim's thighs and places his fists between the bottom of the victim's breastbone and the navel. The rescuer then executes a series of 6–10 sharp compressions by pushing inward and upward.After the abdominal thrusts, the rescuer repeats the process of lifting the chin, moving the tongue, feeling for and possibly removing the foreign material. If the airway is not clear, the rescuer repeats the abdominal thrusts as often as necessary. If the foreign object has been removed, but the victim is not breathing, the rescuer starts CPR.

Performing the Heimlich maneuver under special circumstances
OBVIOUSLY PREGNANT AND VERY OBESE PEOPLE. The main difference in performing the Heimlich maneuver on this group of people is in the placement of the fists. Instead of using abdominal thrusts, chest thrusts are used. The fists are placed against the middle of the breastbone, and the motion of the chest thrust is in and downward, rather than upward. If the victim is unconscious, the chest thrusts are similar to those used in CPR.
CHILDREN. The technique in children over one year of age is the same as in adults, except that the amount of force used is less than that used with adults in order to avoid damaging the child's ribs, breastbone, and internal organs.
INFANTS UNDER ONE YEAR OLD. The rescuer sits down and lays the infant along his or her forearm with the infant's face pointed toward the floor. The rescuer's hand supports the infant's head, and his or her forearm rests on his or her own thigh for additional support. Using the heel of the other hand, the rescuer administers four or five rapid blows to the infant's back between the shoulder blades.After administering the back blows, the rescuer sandwiches the infant between his or her arms, and turns the infant over so that the infant is lying face up supported by the opposite arm. Using the free hand, the rescuer places the index and middle finger on the center of the breastbone and makes four sharp chest thrusts. This series of back blows and chest thrusts is alternated until the foreign object is expelled.
SELF-ADMINISTRATION OF THE HEIMLICH MANEUVER. To apply the Heimlich maneuver to oneself, one should make a fist with one hand and place it in the middle of the body at a spot above the navel and below the breastbone, then grasp the fist with the other hand and push sharply inward and upward. If this fails, the victim should press the upper abdomen over the back of a chair, edge of a table, porch railing or something similar, and thrust up and inward until the object is dislodged.PreparationAny lay person can be trained to perform the Heimlich maneuver. Knowing how may save someone's life.
Before doing the maneuver, it is important to determine if the airway is completely blocked. If the person choking can talk or cry, Heimlich maneuver is not appropriate. If the airway is not completely blocked, the choking victim should be allowed to try to cough up the foreign object on his or her own.
Aftercare
It is used only when the airway is totally obstructed, as shown by inability to speak or breathe.
资料来源：answers.com