Breathing that slows down or stops from any cause is called apnea. Apnea can come once in a while and be temporary. This can occur with obstructive sleep apnea, for example. Prolonged apnea means a person has stopped breathing. This is also called respiratory arrest when the heart is still active. Prolonged apnea accompanied by lack of any cardiac activity and a patient who is not responsive is called cardiac arrest.

Prolonged apnea (respiratory arrest) is a life-threatening disorder that requires immediate medical attention and first aid.

If a person with any type of apnea turns blue, has a seizure, becomes limp, remains drowsy, or is unconscious, immediately seek medical attention and call 911.

Apnea can occur for many different reasons. The most common causes of apnea in infants and small children are generally quite different from the most common causes in adults.

In infants and children, the most common cause of cardiac arrest (lack of an effective heartbeat) is respiratory arrest. In adults, the opposite usually occurs: Cardiac arrest leads to respiratory arrest.

Common causes of apnea in infants and young children include:

• Asthma
• Bronchiolitis
• Choking
• Encephalitis
• Gastroesophageal reflux (heartburn)
• Holding one's breath
• Meningitis
• Pneumonia
• Premature birth
• Seizures

Common causes of apnea in adults include:

• Asthma or other lung diseases
• Cardiac arrest
• Choking
• Drug overdose, especially drugs such as alcohol, narcotic pain killers, barbiturates, anesthetics, and other depressants (See also: Drug abuse first aid)
• Obstructive sleep apnea

Other causes of apnea include:

• Head or brain-stem injury
• Irregular heartbeat (arrhythmias)
• Metabolic disorders
• Near-drowning
• Nervous system disorders

If a person has stopped breathing, call for emergency help and perform CPR (if you know how). When in a public place, look for an Automated External Defibrillator (AED) and follow the directions.

CPR or other emergency measures will be done in an emergency room or by an ambulance EMT (emergency medical technician).

Once the patient is stable, the doctor will do a physical exam and ask questions about the person's medical history. Questions may include:

• Time pattern
  • Has this ever happened before?
  • How long did the event last?
  • Has the person had repeated, brief episodes of apnea?
  • Did the episode end with a sudden deep snorting breath?
  • Did the episode occur while awake or asleep?
• Recent heath history
  • Has there been any recent history of an accident or injury?
  • Has the person been ill recently?
  • Had there been any breathing difficulty before the breathing stopped?
  • What other symptoms are also present?
  • What medication does the person take?
  • Does the person use street drugs?

The doctor will listen to the person's heart sounds and breath sounds. Diagnostic tests may be performed. They include:

• Arterial blood gas
• Chest x-ray
• ECG
• Other blood tests

Marx, J. Rosen's Emergency Medicine: Concepts and Clinical Practice. 6th ed. St. Louis, Mo: Mosby; 2006.

Fleisher KE, Krieger AC. Current trends in the treatment of obstructive sleep apnea. J Oral Maxillofac Surg. 2007: 65 (10): 2056-68.