Asphyxia is one of the most common causes of death among living beings. An Indian study revealed that about  8.8% of all medico-legal deaths registered at a hospital are due to violent/mechanical asphyxia alone. Moreover, the major age group of the victims was between 21 to 30 years, with about 65% of them being males.

In this article, we are going to talk about the various aspects of asphyxia, including the definition of asphyxia, types of asphyxial deaths, causes of asphyxiation, symptoms of asphyxial death and how to prevent asphyxia.

Join Doctutorials’ online courses to gain more detailed knowledge and a better understanding of other such topics. Discover more here.

What is Asphyxia?

Asphyxia is defined as “A condition caused by interference with the exchange of oxygen and carbon dioxide in the body”. ‘Asphyxia’ is a Greek word which means “pulselessness”. 

The nature of death in asphyxial deaths can be homicidal, suicidal as well as accidental. Hanging, a form of asphyxial death, is quite commonly used as a suicide method. 

What are the Different Types of Asphyxia?

Asphyxia, as we look into it, can be of various types. Majorly these are grouped into 8 broad headings.

1. Mechanical/Violent (Physical) 

This features mechanical interference to the passage of air into the respiratory tract, which could be facilitated by:

• Closure of external respiratory orifices (openings)
• Closure of the air passages by external force (strangulation, hanging, throttling, burking) or by impaction of foreign objects (choking or gagging)
• Pressure on the chest (in a stampede or building collapse)
• Occlusion of the respiratory tract by fluids (drowning)

2. Pathological

Infection or disease of the upper respiratory tract or lungs ceases oxygen’s entry to the lungs. These are commonly seen in lung abscesses, laryngeal oedema, lung tumours, or laryngeal spasms.

3. Toxic/Chemical

The respiratory muscles cease to function due to the paralysis of the respiratory centre, which is seen in poisoning with morphine, barbiturates, or strychnine. Another mechanism of asphyxiation is through the inhibition of the oxidative process in case of cyanide poisoning.

4. Environmental

Breathing in environments where the air pressure is low or the air lacks oxygen can lead to this particular type of asphyxia. Examples include climbing at high altitudes, flying, and inhaling carbon monoxide, sewer gas, or pure helium.

5. Traumatic

It includes asphyxiation due to blunt trauma to the chest, which can lead to pneumothorax, haemothorax or pulmonary embolus, which in turn interferes with the oxygenation and perfusion capacity of the living lung parenchyma.

6. Positional/Postural 

It refers to abnormal positioning of the body, leading to impaired gaseous exchange. Examples include hogtying and jack-knife positions in alcoholics and addicts.

7. Iatrogenic

This is defined as asphyxia due to medical reasons which were originally intended to improve the condition of the patient. An example includes paralysis of respiratory muscles during anaesthesia meant for a surgical procedure.

8. Birth Asphyxia

This occurs as a result of low oxygen delivery to the foetus during pregnancy or at the time of delivery.

What are the Causes of Asphyxia?

A person can asphyxiate due to the following major reasons:

• Anaphylactic Shock

A person can have an allergic reaction to a particular allergen, like pollen. When the allergic reaction is so severe that it poses a threat to life, it is termed Anaphylaxis or Anaphylactic shock. In this case, the airways start to constrict, which can lead to physical or mechanical asphyxia.

• Asthma

Chronic asthma patients experience episodes of asthma attacks. The mechanism is quite similar to an allergic reaction, causing the airways to constrict.

The triggering agents for an asthma attack include pet hair, cigarette smoke, pollution, etc.

• Aspiration

It refers to aspiration or entry of liquid into the lungs, which happens in drowning.

• Choking

This happens when good or any foreign object gets stuck in your airways and restricts the air from entering your lungs. This is commonly seen in older patients and babies.

• Strangulation

It refers to mechanical constriction of the airways caused by the application of external force using some kind of ligature (such as rope, wire, or cord).

• Autoerotic Strangulation

It is also known as De Clerambault Syndrome or Koczwarism. It is a form of strangulation in which a person obtains sexual gratification by asphyxiating themselves.

• Suffocation

Also known as smothering, it is a condition in which something heavy is used to cover one’s face or chest, impairing breathing. It can also happen if a person is stuck in a place devoid of oxygen.

• Drug Overdose

Some drugs, like opioids, slow down your breathing. When used in an excessive amount, it can slow your breathing to such an extent that your body starts to undergo asphyxiation.

• Seizures

These are uncontrolled and violent spasms of the muscles in your body. This can impair your body’s oxygen delivery system, leading to asphyxia.

• Disease/Injury

A few conditions, such as heart failure or a broken neck, can also cause obstruction of the air passages.

What are the Symptoms of Asphyxia?

Some of the generalised symptoms of asphyxia include

• Unconsciousness
• Loss of ability to speak (Dysarthria)
• Cyanosis (bluish tinting, especially seen in the face, lips, and nail beds)
• Loss of control of urination/defaecation 
• Dysphagia (difficulty in swallowing)
• Dyspnoea (shortness of breath)
• Hyperventilation
• Coughing
• Amnesia
• Rough or hoarse voice
• Headaches
• Dizziness

How to Prevent Asphyxia?

Prevention tips for asphyxia differ according to age. Special care needs to be taken in case of young children and babies.

For Young Children and Infants	Never leave your baby unattendedTake proper care while positioning your babies in carriers or car seats.Make small portions of foodNever leave your baby unattended in water, even in bathtubs.Keep the cords of the curtain blinds out of reach for children.Remove soft bedding and pillows from the children’s beds.
For General Population	Set up carbon monoxide detectors at homeMake sure to follow safety instructions in and near water bodiesKeep your medication close if you have asthmaIf you are on opioid medications, keep Naloxane at all times with youBe aware of life-saving techniques like Heimlich Manoeuver and CPR.

FAQs about Asphyxia

1. What are some of the major causes of birth asphyxia?

Some of the major causes of birth asphyxia include too little oxygen in the mother’s blood, early separation of the placenta, and prolonged labour.

2. What is the major difference between hypoxia and asphyxia?

Hypoxia refers to decreased oxygen saturation in the blood or tissues, while asphyxia refers to impaired oxygen delivery in the body. Hypoxia can result from asphyxia.

3. Is the crying of a baby a warning sign for asphyxia?

If the baby is not getting enough oxygen in the air it breathes, its brain triggers it to cry to increase the supply of oxygen.

4. Which gases can cause asphyxia?

Some of the gases that are notorious for causing asphyxia include methane, hydrogen sulphide, nitrogen, argon, helium, carbon monoxide, butane, and propane.

5. What are the major notable stages of asphyxia?

The significant stages of asphyxia include initial apnoea, followed by dyspnoea and terminal apnoea, with the final stage being cardiac arrest.

Conclusion

Asphyxia is a major concern as it can be silently life-threatening as well. Hence it is important to know well about the condition, what causes it, and how to prevent it. 
This article covers all the major aspects of asphyxia. To better understand and increase your command of the topic and forensic medicine, you can join Dr Jayaprakash’s course through the Doctutorials application.