Choking

Overview
Choking is the mechanical obstruction of the flow of air from the environment into the lungs. Choking prevents breathing, and can be partial or complete, with partial choking allowing some, although inadequate, flow of air into the lungs. Prolonged or complete choking results in asphyxiation which leads to hypoxia and is potentially fatal.

Choking can be caused by:
 * Introduction of a foreign object into the airway, which becomes lodged in the pharynx, larynx or trachea.
 * Respiratory diseases that involve obstruction of the airway.
 * Compression of the laryngopharynx, larynx or trachea in strangles.

Foreign objects
The type of choking most commonly recognised as such by the public is the lodging of foreign objects in the airway. This type of choking is often suffered by small children, who are unable to appreciate the hazard inherent in putting small objects in their mouth. In adults, it mostly occurs whilst the patient is eating.

Symptoms and Clinical Signs

 * The person cannot speak or cry out.
 * The person's face turns blue (cyanosis) 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 any or all of the above, and then becomes unconscious.

Treatment
Choking can be treated with a number of different procedures, with both basic techniques available for first aiders and more advanced techniques available for health professionals.

Many members of the public associate abdominal thrusts, also known as the 'Heimlich Maneuver' with the correct procedure for choking, which is partly due to the widespread use of this technique in movies, which in turn was based on the widespread adoption of this technique in the USA at the time, although it also produced easy material for writers to create comedy effect.

Most modern protocols (including those of the American Heart Association and the American Red Cross, who changed policy in 2006 from recommending only abdominal thrusts) involve several stages, designed to apply increasingly more pressure.

The key stages in most modern protocols include:

Encouraging the victim to cough
This stage was introduced in many protocols as it was found that many people were too quick to undertake potentially dangerous interventions, such as abdominal thrusts, for items which could have been dislodged without intervention. Also, if the choking is caused by irritating liquids (alcohol, spice, mint, gastric acid, etc.) or anything without a solid shape, and if conscious, the patient should be allowed to drink water on their own to try to clear the throat. Since the airway is already closed, there is very little danger of water entering the lungs. Coughing is normal after most of the irritant has cleared, and at this point the patient will probably refuse any additional water for a short time.

Back slaps
The majority of protocols now advocate the use of hard blows with the heel of the hand on the upper back of the victim. The number to be used varies by training organisation, but is usually between 5 and 20.

The back slap is designed to use percussion to create pressure behind the blockage, assisting the patient in dislodging the article. In some cases the physical vibration of the action may also be enough to cause movement of the article sufficient to allow clearance of the airway.

Almost all protocols give back slaps as a technique to be used prior to the consideration of potentially damaging interventions such as Abdominal thrusts

Abdominal thrusts
Abdominal thrusts, also known as the Heimlich Maneuver (after Henry Heimlich, who first described the procedure in a June 1974 informal article entitled "Pop Goes the Cafe Coronary," published in the journal Emergency Medicine. Edward A. Patrick, MD, PhD, an associate of Heimlich, has claimed to be the uncredited co-developer of the procedure, and has been quoted calling it the Patrick maneuver. Heimlich has objected to the name "abdominal thrusts" on the grounds that the vagueness of the term "abdomen" could cause the rescuer to exert force at the wrong site.

Performing abdominal thrusts involves a rescuer standing behind a patient and using their hands to exert pressure on the bottom of the diaphragm. This compresses the lungs and exerts pressure on any object lodged in the trachea, hopefully expelling it. This amounts to an artificial cough.

Due to the forceful nature of the procedure, even when done correctly it can injure the person on whom it is performed. Bruising to the abdomen is highly likely and more serious injuries can occur, including fracture of the xiphoid process or ribs.

Self treatment with abdominal thrusts
A person may also perform abdominal thrusts on themselves by using a fixed object such as a railing or the back of a chair to apply pressure where a rescuers hands would normally do so. As with other forms of the procedure, it is likely that internal injuries may result.

Other uses of abdominal thrusts
Dr. Heimlich also advocates the use of the technique as a treatment for drowning and asthma attacks, but Heimlich's promotion to use the maneuver to treat these conditions resulted in marginal acceptance. Criticism of these uses has been the subject of numerous print and television reports which resulted from an internet and media campaign by his son, Peter M. Heimlich, who alleges that in August 1974 his father published the first of a series of fraudulent case reports in order to promote the use of abdominal thrusts for near-drowning rescue.

Modified chest thrusts
A modified version of the technique is sometimes taught for use with pregnant women and obese casualties. The rescuer places their hand in the center of the chest to compress, rather than in the abdomen.

CPR
In most protocols, once the patient has become unconscious, the emphasis switches to performing CPR, involving both chest compressions and artificial respiration. These actions are often enough to dislodge the item sufficiently for air to pass it, allowing gaseous exchange in the lungs.

Finger Sweeping
Some protocols advocate the use of the rescuer's finger to 'sweep' foreign objects away once they have reached the mouth. However, many modern protocols recommend against the use of the finger sweep as if the patient is conscious, they will be able to remove themselves, or if they are unconscious the rescuer should simply place them in the recovery position (where the object should fall out due to gravity). There is also a risk of causing further damage (for instance inducing vomiting) by using a finger sweep technique.

Direct vision removal
The advanced medical procedure to remove such objects is inspection of the airway with a laryngoscope or bronchoscope, and removal of the object under direct vision, followed by CPR if the patient does not start breathing on their own. Severe cases where there is an inability to remove the object may require cricothyrotomy.