In the 16th century, Flemish physician 
Andreas Vesalius

described how a suffocating animal 
could be kept alive

by inserting a tube into its trachea
and blowing air to inflate its lungs.

In 1555, this procedure didn’t warrant
much acclaim.

But today, Vesalius’s treatise 
is recognized

as the first description 
of mechanical ventilation—

a crucial practice in modern medicine.

To appreciate the value of ventilation,

we need to understand how 
the respiratory system works.

We breathe by contracting our diaphragms, 
which expands our chest cavities.

This allows air to be drawn in, 
inflating the alveoli—

millions of small sacs inside our lungs.

Each of these tiny balloons is surrounded 
by a mesh of blood-filled capillaries.

This blood absorbs oxygen 
from the inflated alveoli

and leaves behind carbon dioxide.

When the diaphragm is relaxed,

the CO2 is exhaled alongside 
a mix of oxygen and other gases.

When our respiratory systems 
are working correctly,

this process happens automatically.

But the respiratory system can be 
interrupted by a variety of conditions.

Sleep apnea stops diaphragm muscles
from contracting.

Asthma can lead to inflamed airways 
which obstruct oxygen.

And pneumonia, often triggered 
by bacterial or viral infections,

attacks the alveoli themselves.

Invading pathogens kill lung cells,

triggering an immune response 
that can cause lethal inflammation

and fluid buildup.

All these situations render the lungs 
unable to function normally.

But mechanical ventilators 
take over the process,

getting oxygen into the body 
when the respiratory system cannot.

These machines can bypass 
constricted airways,

and deliver highly oxygenated air 
to help damaged lungs diffuse more oxygen.

There are two main ways 
ventilators can work—

pumping air into the patient’s lungs 
through positive pressure ventilation,

or allowing air to be passively drawn 
in through negative pressure ventilation.

In the late 19th century,

ventilation techniques largely 
focused on negative pressure,

which closely approximates 
natural breathing

and provides an even distribution 
of air in the lungs.

To achieve this, doctors created 
a tight seal around the patient’s body,

either by enclosing them in 
a wooden box or a specially sealed room.

Air was then pumped 
out of the chamber,

decreasing air pressure,
and allowing the patient’s chest cavity

to expand more easily.

In 1928, doctors developed 
a portable, metal device

with pumps powered 
by an electric motor.

This machine, known as the iron lung,

became a fixture in hospitals 
through the mid-20th century.

However, even the most compact 
negative pressure designs

heavily restricted a patient’s movement

and obstructed access for caregivers.

This led hospitals in the 1960’s to shift 
towards positive pressure ventilation.

For milder cases, 
this can be done non-invasively.

Often, a facemask is fitted 
over the mouth and nose,

and filled with pressurized air 
which moves into the patient’s airway.

But more severe circumstances

require a device that takes over 
the entire breathing process.

A tube is inserted 
into the patient’s trachea

to pump air directly into the lungs,

with a series of valves 
and branching pipes

forming a circuit for inhalation 
and exhalation.

In most modern ventilators,

an embedded computer system

allows for monitoring the patient’s 
breathing and adjusting the airflow.

These machines aren’t used 
as a standard treatment,

but rather, as a last resort.

Enduring this influx of pressurized air 
requires heavy sedation,

and repeated ventilation 
can cause long-term lung damage.

But in extreme situations,

ventilators can be the difference 
between life and death.

And events like the COVID-19 pandemic

have shown that they’re even more 
essential than we thought.

Because current models 
are bulky, expensive,

and require extensive training to operate,
most hospitals only have a few in supply.

This may be enough 
under normal circumstances,

but during emergencies, 
this limited cache is stretched thin.

The world urgently needs more low-cost
and portable ventilators,

as well as a faster means 
of producing and distributing

this life-saving technology.