Asphyxia: Types, Causes, Symptoms

Medically Reviewed by Zilpah Sheikh, MD on December 05, 2023
8 min read

Asphyxia, also known as suffocation or asphyxiation, happens when your body doesn't get enough oxygen to keep you from passing out. It can be a life-threatening situation.

When you breathe normally, first you take in oxygen. Your lungs send that oxygen into your blood, which carries it to your tissues. Then your cells use it to make energy. Any interruption to the process of breathing in oxygen or breathing out carbon dioxide can make you pass out or even lose your life.

Asphyxia vs. hypoxia

Hypoxia is when you have low levels of oxygen in your blood or low oxygen delivery to your tissues. It can range from mild to serious. Some of your body’s tissues can function for a long time with low levels of oxygen, while others get damaged quickly.

Asphyxia and hypoxia both affect how your body receives oxygen. However, asphyxia is when oxygen isn't getting to your airways, while hypoxia means your tissues can't take in or use oxygen as effectively as they should. Asphyxia can cause hypoxia, but not vice versa.

There are many ways oxygen can get blocked from your body. They include:

Physical (mechanical) asphyxia

Physical or mechanical asphyxia happens when a­­ force or object keeps you from breathing. This type of asphyxia is different from chemical asphyxia, where a chemical keeps oxygen from reaching your cells. There are several types of physical asphyxia.

Compressive asphyxia. This type of physical asphyxia happens when an outside force keeps you from expanding your chest to breathe. Your lungs are “crushed” and can’t take in air. This can happen from a crowd of people pressing against your body, or a person’s weight on your chest.

Traumatic asphyxia

A type of physical asphyxia, traumatic asphyxia is similar to compression asphyxia, but it tends to happen quickly and with strong force. Examples include car accidents, or when a large object, such as a piece of furniture, falls on your chest or stomach. Traumatic asphyxia causes the blood in your heart to rush backward in your veins toward your neck and brain.

Positional asphyxia

If the position of your body obstructs your breathing, that’s called positional asphyxiation. The most common reason this happens is if someone isn’t strong enough to move when their breathing is blocked. An example is an infant who can’t lift their head when their position is keeping air from getting to their lungs.

Acute asphyxia

When asphyxia is severe and sudden, it’s acute asphyxia. Traumatic asphyxia is an example of acute asphyxia.

Asphyxia in newborns (birth asphyxia)

Sometimes, an unborn child gets too little oxygen during pregnancy. This might happen, for example, because of a lack of oxygen in the mother's blood, or problems with the placenta. During delivery, the baby may get less oxygen because of umbilical cord problems or a long labor.

How harmful this is depends on how long the baby is without oxygen, how low their level of oxygen goes, and how quickly they get treatment.

You can asphyxiate for many different reasons, including:

  • Anaphylaxis. When you have an allergic reaction that's life-threatening, it’s called anaphylaxis. Anaphylaxis causes airways to swell and close, which may lead to physical asphyxia. Two common causes of anaphylaxis are allergies to bee stings and peanuts.

  • Asthma. This chronic lung condition causes your airways to swell and close off when you’re exposed to triggers such as pollution, pets, exercise, or cigarette smoke.

  • Choking (foreign object obstruction). This is when food or an object gets stuck in your airway and blocks air from getting to your lungs. Older adults are at a higher risk, especially those who live alone, wear dentures, or have trouble swallowing. Babies and toddlers also have higher odds of choking on large pieces of food or things they put in their mouths.

  • Aspiration (drowning). It's different from choking. Aspiration happens when a substance, (for example, something you eat or drink) enters your airway or lungs. The substance crowds out the air in your body. Drowning is the most common type of aspiration.

  • Suffocation (smothering). Suffocation happens when something heavy covers your face or chest and keeps you from breathing. It can also happen when you're in a place where oxygen runs out, such as a closed-in, airtight space.

  • Strangulation. If a cord, rope, or other object long enough to go around your neck presses on your airway, it can block air from reaching your lungs.

  • Autoerotic strangulation. This strangulation is done on purpose as a sexual stimulation method. When this type of solo strangulation goes on for too long, it can cause death. Another form is erotic strangulation, where one partner strangles another.

  • Drug overdose. Opioids affect your breathing. When you take too high a dose, it can slow down your breathing to the point that your body doesn't take in enough oxygen.

  • Seizure. It can cause asphyxia in several ways. Epileptic seizures may make your breathing suddenly pause (also called apnea) and lower the oxygen in your body to life-threatening levels. Also, during a seizure, your body may move in such a way that your airway gets covered, blocking your breathing.

  • Illnesses or injuries. Conditions such as heart failure or a broken neck can cause physical asphyxia.

Chemical asphyxia

Chemicals that can keep your cells from taking in oxygen and cause asphyxia include:

  • Carbon monoxideThis is a colorless, odorless gas that comes from burning different types of fuel. If you breathe in too much of it, the gas builds up in your body and replaces the oxygen in your blood.
  • Cyanide. It keeps cells from taking oxygen in. You're at risk of cyanide poisoning if you breathe smoke during a fire, have contact with certain industrial chemicals, or work in jobs such as mining or metalworking.
  • Hydrogen sulfide. This gas smells like a rotten egg. It can come from sewage, liquid manure, sulfur hot springs, and natural gas. If you breathe in too much, it can keep oxygen from entering your cells, much like cyanide does.

Many causes of asphyxia are accidental, but some things can increase your chances of certain types of asphyxiation. 

For example, premature and low birth-weight infants are at a higher risk of positional asphyxiation. So are people with asthma or serious allergies. Activities such as taking opioid drugs and participating in erotic strangulation can also raise your risk of having asphyxia.

Some symptoms of asphyxiation happen right away, and some develop when you don't get enough oxygen over time. They include:

  • Loss of consciousness
  • Inability to speak
  • A red, purple, blue, or gray tint to your face or lips
  • Peeing or pooping without meaning to
  • Trouble swallowing
  • Shortness of breath
  • Quick or deep breathing (hyperventilation)
  • Coughing
  • Raspy or hoarse voice
  • Memory loss
  • Dizziness
  • Headaches

In some cases, the cause of asphyxia will be obvious, such as an accident or injury. If you notice someone suddenly unable to breathe, ask if they’re choking. If they can’t talk or cough, watch for these signs of asphyxiation:

  • Clutching at the throat with hands crossed
  • Shallow coughing
  • Wheezing
  • Inability to talk
  • Passing out

A baby who can’t breathe or give you signals they’re choking may have changes in behavior, trouble breathing, or a weak cry or shallow cough.

If your doctor doesn’t know what's causing your asphyxia, you may need an imaging test such as an X-ray or bronchoscopy. That's a technique where your doctor uses a flexible tube with a small camera on the end to look at your airway.

Asphyxia is an emergency, and you need immediate treatment for it. The type of treatment you need will depend on what’s causing your asphyxia and how serious it is. You may need:

Cardiopulmonary resuscitation (CPR). It's done to get blood flowing to your vital organs until your heart starts beating again. CPR requires hard chest compressions on your sternum, also called breastbone.

Mouth-to-mouth resuscitation. After drowning or a drug overdose, mouth-to-mouth resuscitation can help get someone breathing. Often, it's done together with CPR. 

Heimlich maneuver. It helps dislodge an object stuck in your airway. To do it, someone stands behind you, wraps their arms around your torso, and thrusts upward with their clasped fists. For infants, you lay them chest-down on your outstretched forearm and use the heel of your hand to strike several blows against their back.

Medications to open airways closed from certain conditions. Steroid inhalers can open airways after an asthma attack. Epinephrine (EpiPen) injections can open airways after a serious allergic reaction, and naloxone (Narcan) can restart breathing after an opioid overdose.

Oxygen therapy. This uses some combination of a breathing tube, oxygen mask, nose tube, or a ventilator to deliver oxygen to your body. This can help when your body is having trouble getting enough oxygen into your blood and tissues.

In many cases, preventing asphyxia simply means being careful.

For infants and small children, take these precautions:

  • Position babies correctly in car seats or carriers, and don’t leave them unattended.
  • Cut foods that are hard to chew into small pieces.
  • Don’t leave babies in water unattended. Even a bathtub with small amounts of water can be deadly.
  • Remove cords from blinds in your home, tie them out of reach, or use cordless blinds.
  • Keep soft bedding and pillows out of infant beds.

In general, keep the following in mind to prevent asphyxia:

  • Install carbon monoxide detectors in your home.
  • Follow safety guidelines whenever you're around a body of water.
  • Keep medications on hand at all times if you have asthma or serious allergies.
  • If you or a friend uses opioid drugs, keep naloxone (Narcan) with you.
  • Learn techniques such as CPR and the Heimlich maneuver.