Explainer: All you need to know about ventilators

A doctor at the University Hospital Eppendorf in Germany explaining how a ventilator works. PHOTO | AXEL HEIMKEN | POOL | AFP

What you need to know:

  • Ventilators are primarily used in intensive care medicine, home care, emergency medicine and in anaesthesiology.
  • The amount of oxygen the patient receives while on a ventilator can be controlled through a monitor.

Based on news reports from across the world, one of the major challenges in fighting the coronavirus (Covid-19) pandemic is the limited number of ventilators in hospitals and quarantine centres.

Ventilators are a critical equipment in saving the lives of people infected with the coronavirus, particularly those who are in the advanced stages of infection.

But what exactly are ventilators and how do they help? Here is what you need to know.

• What is a ventilator?

A ventilator is a machine that takes over a person's breathing when his or her lungs have failed due to a disease.

These machines are used to assist or replace spontaneous breathing by moving breathable air into and out of the lungs to deliver oxygen to a patient.

Modern ventilators are computerised. Patients can also be ventilated using a simple hand-operated bag-valve mask.

Ventilators are primarily used in intensive care medicine, home care, emergency medicine (as standalone units) and in anaesthesiology (as a component of an anaesthesia machine).

• How do ventilators work?

Ventilators gently blow air (or air with increased amounts of oxygen) into the airways to the lungs.

These airways include the nose, mouth, larynx or voice box, trachea, and bronchioles.

In a process known as intubation, one end of a breathing tube is inserted into the windpipe and the other end is attached to the ventilator.

However, in most cases, the breathing tube is put into a patient's windpipe through the nose or the mouth.

The tube is then moved down into the throat. A tube placed like this is called an endotracheal tube.

There are two types of medical ventilation: the mechanical ventilation or respirator that is inserted into a person's throat, and a non-invasive ventilation where breathing support is administered through a face mask, nasal mask, or a helmet.

The amount of oxygen the patient receives while on a ventilator can be controlled through a monitor connected to the machine.

If the patient's condition is critical, the monitor will be set to send an alarm, indicating an increase in air pressure.

• Who needs ventilators?

Ventilators are classified as life-critical systems because without them a patient may die.

It is for this reason that precautions must be taken to ensure that they are highly reliable, including their power-supply.

These machines are mostly used for short periods such as during surgery, when a patient is under general anaesthesia.

They are also used after surgery, when a patient is recovering in the intensive care unit.

Lung disease

A ventilator may also be used during treatment for a serious lung disease or other condition that affects normal breathing.

These conditions include:
— Pneumonia and other respiratory infections.

— Lung diseases like COPD (chronic obstructive pulmonary disease).

— Upper spinal cord injuries, polio, amyotrophic lateral sclerosis (ALS), myasthenia gravis and other diseases or factors that affect the nerves and muscles involved in breathing.

— Brain injury.

— Stroke.

— Drug overdose.

Then can also be used for people who have breathing difficulty, shallow breathing, acute respiratory distress syndrome and shortness of breath (dyspnoea).

• Are patients with coronavirus likely to use ventilators?

According to the World Health Organisation (WHO), about 80 per cent of people with the coronavirus (Covid-19) recover without needing hospital treatment.

However, one in six persons becomes seriously ill and can develop breathing difficulties.

Before deciding to put a patient on a ventilator, doctors look for signs of respiratory failure.

Some of these signs include an increased breathing rate, an indication of distress.

The normal breathing rate of a human being is about 15 breaths a minute. But if the rate gets to about 28 times a minute, ventilation is required.

In severe cases, the coronavirus may damage the lungs resulting to lung failure and difficulty in breathing as a result of fluid build-up. When this happens, ventilators are urgently needed to help push air with higher oxygen levels to the lungs.

The ventilator also has a humidifier, which warms up the medical air to match a patient's body temperature.

In addition, patients are also given medication to relax the respiratory muscles so that breathing can be fully regulated by the ventilator.

• Can I buy a ventilator for home use?

While you are free to acquire a ventilator for home care, it has to be done on the recommendation of a specialist.

Ventilators are mostly used in intensive care units in hospitals and emergency vehicles such as ambulances.

They are also very expensive — ranging between Sh500,000 and Sh5 million.

Currently, due to the coronavirus pandemic, ventilators are in short supply around the world with countries such as Italy, the UK and the US reporting shortages.

Ventilator makers are under intense pressure to increase production even as the pandemic continues to disrupt transport and supply of crucial parts, such as hoses, valves, motors and electronics.

Some companies are even looking at 3D printing of some of the parts.

• What is the importance of ventilators for patients?

The main purpose of a ventilator is to allow the patient time to heal.

In most cases, as soon as a patient can breathe effectively on their own, they are taken off the mechanical ventilator.

Other benefits of ventilators include:

— Helping a patient not have to work as hard to breathe, thus allowing their respiratory muscles to rest.

— Giving a patient time to recover.

— Helping the patient get adequate oxygen and clear out carbon dioxide from their system.

— Preserving a stable airway and preventing injury from aspiration.

Are there any risks associated with ventilators?

The main risk associated with ventilators is infection, as a breathing tube may allow germs to enter the lungs.

The risk of infection increases with the period that one is under ventilation and studies show that the risk is highest around two weeks.

Other risks include lung damage, which may be caused by either over inflation or repetitive opening and collapsing of the small air sacs of the lungs.

Another risk is that some patients might need to be weaned off the ventilator and may require prolonged support.