How do ventilators work? - Alex Gendler
-
0:07 - 0:11In the 16th century, Flemish physician
Andreas Vesalius -
0:11 - 0:15described how a suffocating animal
could be kept alive -
0:15 - 0:21by inserting a tube into its trachea
and blowing air to inflate its lungs. -
0:21 - 0:26In 1555, this procedure didn’t warrant
much acclaim. -
0:26 - 0:29But today, Vesalius’s treatise
is recognized -
0:29 - 0:33as the first description
of mechanical ventilation— -
0:33 - 0:36a crucial practice in modern medicine.
-
0:36 - 0:39To appreciate the value of ventilation,
-
0:39 - 0:43we need to understand how
the respiratory system works. -
0:43 - 0:49We breathe by contracting our diaphragms,
which expands our chest cavities. -
0:49 - 0:54This allows air to be drawn in,
inflating the alveoli— -
0:54 - 0:58millions of small sacs inside our lungs.
-
0:58 - 1:04Each of these tiny balloons is surrounded
by a mesh of blood-filled capillaries. -
1:04 - 1:09This blood absorbs oxygen
from the inflated alveoli -
1:09 - 1:13and leaves behind carbon dioxide.
-
1:13 - 1:15When the diaphragm is relaxed,
-
1:15 - 1:21the CO2 is exhaled alongside
a mix of oxygen and other gases. -
1:21 - 1:24When our respiratory systems
are working correctly, -
1:24 - 1:27this process happens automatically.
-
1:27 - 1:31But the respiratory system can be
interrupted by a variety of conditions. -
1:31 - 1:36Sleep apnea stops diaphragm muscles
from contracting. -
1:36 - 1:41Asthma can lead to inflamed airways
which obstruct oxygen. -
1:41 - 1:46And pneumonia, often triggered
by bacterial or viral infections, -
1:46 - 1:49attacks the alveoli themselves.
-
1:49 - 1:52Invading pathogens kill lung cells,
-
1:52 - 1:56triggering an immune response
that can cause lethal inflammation -
1:56 - 1:58and fluid buildup.
-
1:58 - 2:03All these situations render the lungs
unable to function normally. -
2:03 - 2:07But mechanical ventilators
take over the process, -
2:07 - 2:12getting oxygen into the body
when the respiratory system cannot. -
2:12 - 2:15These machines can bypass
constricted airways, -
2:15 - 2:22and deliver highly oxygenated air
to help damaged lungs diffuse more oxygen. -
2:22 - 2:25There are two main ways
ventilators can work— -
2:25 - 2:30pumping air into the patient’s lungs
through positive pressure ventilation, -
2:30 - 2:36or allowing air to be passively drawn
in through negative pressure ventilation. -
2:36 - 2:38In the late 19th century,
-
2:38 - 2:42ventilation techniques largely
focused on negative pressure, -
2:42 - 2:44which closely approximates
natural breathing -
2:44 - 2:49and provides an even distribution
of air in the lungs. -
2:49 - 2:54To achieve this, doctors created
a tight seal around the patient’s body, -
2:54 - 3:01either by enclosing them in
a wooden box or a specially sealed room. -
3:01 - 3:03Air was then pumped
out of the chamber, -
3:03 - 3:07decreasing air pressure,
and allowing the patient’s chest cavity -
3:07 - 3:10to expand more easily.
-
3:10 - 3:15In 1928, doctors developed
a portable, metal device -
3:15 - 3:18with pumps powered
by an electric motor. -
3:18 - 3:21This machine, known as the iron lung,
-
3:21 - 3:26became a fixture in hospitals
through the mid-20th century. -
3:26 - 3:30However, even the most compact
negative pressure designs -
3:30 - 3:33heavily restricted a patient’s movement
-
3:33 - 3:36and obstructed access for caregivers.
-
3:36 - 3:42This led hospitals in the 1960’s to shift
towards positive pressure ventilation. -
3:42 - 3:46For milder cases,
this can be done non-invasively. -
3:46 - 3:50Often, a facemask is fitted
over the mouth and nose, -
3:50 - 3:55and filled with pressurized air
which moves into the patient’s airway. -
3:55 - 3:57But more severe circumstances
-
3:57 - 4:02require a device that takes over
the entire breathing process. -
4:02 - 4:05A tube is inserted
into the patient’s trachea -
4:05 - 4:08to pump air directly into the lungs,
-
4:08 - 4:11with a series of valves
and branching pipes -
4:11 - 4:15forming a circuit for inhalation
and exhalation. -
4:15 - 4:17In most modern ventilators,
-
4:17 - 4:19an embedded computer system
-
4:19 - 4:23allows for monitoring the patient’s
breathing and adjusting the airflow. -
4:23 - 4:27These machines aren’t used
as a standard treatment, -
4:27 - 4:30but rather, as a last resort.
-
4:30 - 4:35Enduring this influx of pressurized air
requires heavy sedation, -
4:35 - 4:39and repeated ventilation
can cause long-term lung damage. -
4:39 - 4:42But in extreme situations,
-
4:42 - 4:45ventilators can be the difference
between life and death. -
4:45 - 4:48And events like the COVID-19 pandemic
-
4:48 - 4:52have shown that they’re even more
essential than we thought. -
4:52 - 4:55Because current models
are bulky, expensive, -
4:55 - 5:02and require extensive training to operate,
most hospitals only have a few in supply. -
5:02 - 5:05This may be enough
under normal circumstances, -
5:05 - 5:09but during emergencies,
this limited cache is stretched thin. -
5:09 - 5:14The world urgently needs more low-cost
and portable ventilators, -
5:14 - 5:18as well as a faster means
of producing and distributing -
5:18 - 5:21this life-saving technology.
- Title:
- How do ventilators work? - Alex Gendler
- Speaker:
- Alex Gendler
- Description:
-
View full lesson: https://ed.ted.com/lessons/how-do-ventilators-work-alex-gendler
In the 16th century, 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. Today, Vesalius's treatise is recognized as the first description of mechanical ventilation— a crucial practice in modern medicine. So how do our modern ventilators work? Alex Gendler explains the life-saving technology.
Lesson by Alex Gendler, directed by Artrake Studio
- Video Language:
- English
- Team:
- closed TED
- Project:
- TED-Ed
- Duration:
- 05:21
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