How does blood transfusion work? - Bill Schutt
-
0:06 - 0:12In 1881, doctor William Halsted
rushed to help his sister Minnie, -
0:12 - 0:15who was hemorrhaging after childbirth.
-
0:15 - 0:18He quickly inserted
a needle into his arm, -
0:18 - 0:21withdrew his own blood,
and transferred it to her. -
0:21 - 0:25After a few uncertain minutes,
she began to recover. -
0:25 - 0:28Halsted didn’t know
how lucky they’d gotten. -
0:28 - 0:31His transfusion only worked
because he and his sister -
0:31 - 0:33happened to have the same blood type—
-
0:33 - 0:37something that isn’t guaranteed,
even among close relatives. -
0:37 - 0:40Blood types hadn’t been discovered
by Halsted’s time, -
0:40 - 0:44though people had been experimenting
with transfusions for centuries— -
0:44 - 0:46mostly unsuccessfully.
-
0:46 - 0:50In 1667, a French physician
named Jean-Baptiste Denis -
0:50 - 0:54became the first to try the technique
on a human. -
0:54 - 0:58Denis transfused sheep’s blood
into Antoine Mauroy, -
0:58 - 1:00a man likely suffering from psychosis,
-
1:00 - 1:03in the hopes that it would reduce
his symptoms. -
1:03 - 1:06Afterward, Mauroy was in good spirits.
-
1:06 - 1:09But after a second transfusion,
he developed a fever, -
1:09 - 1:13severe pain in his lower back,
intense burning in his arm, -
1:13 - 1:17and he urinated a thick, black liquid.
-
1:17 - 1:19Though nobody knew it at the time,
-
1:19 - 1:25these were the signs of a dangerous
immune response unfolding inside his body. -
1:25 - 1:28This immune response starts
with the production of proteins -
1:28 - 1:30called antibodies,
-
1:30 - 1:33which distinguish the body’s
own cells from intruders. -
1:33 - 1:38They do so by recognizing
the foreign proteins, or antigens, -
1:38 - 1:40embedded in an intruder’s
cell membrane. -
1:40 - 1:43Antibodies latch onto the antigens,
-
1:43 - 1:47signaling other immune cells to attack
and destroy the foreign cells. -
1:47 - 1:51The destroyed cells are flushed
from the body in urine. -
1:51 - 1:54In extreme cases,
the massive break down of cells -
1:54 - 1:59causes clots in the bloodstream that
disrupt the flow of blood to vital organs, -
1:59 - 2:03overload the kidneys,
and cause organ failure. -
2:03 - 2:06Fortunately, Denis’s patient
survived the transfusion. -
2:06 - 2:10But, after other cross-species
transfusions proved fatal, -
2:10 - 2:13the procedure was outlawed across Europe,
-
2:13 - 2:16falling out of favor
for several centuries. -
2:16 - 2:21It wasn’t until 1901
that Austrian physician Karl Landsteiner -
2:21 - 2:23discovered blood types,
-
2:23 - 2:28the crucial step in the success
of human to human blood transfusions. -
2:28 - 2:32He noticed that when different types
were mixed together, they formed clots. -
2:32 - 2:37This happens when antibodies
latch on to cells with foreign antigens, -
2:37 - 2:39causing blood cells to clump together.
-
2:39 - 2:43But if the donor cells are the same
blood type as the recipient’s cells, -
2:43 - 2:48the donor cells won’t be flagged
for destruction, and won’t form clumps. -
2:48 - 2:50By 1907,
-
2:50 - 2:54doctors were mixing together small amounts
of blood before transfusing it. -
2:54 - 2:57If there were no clumps,
the types were a match. -
2:57 - 3:00This enabled them
to save thousands of lives, -
3:00 - 3:04laying the foundation
for modern transfusions. -
3:04 - 3:07Up to this point, all transfusions
had occurred in real time, -
3:07 - 3:10directly between two individuals.
-
3:10 - 3:13That’s because blood
begins to clot almost immediately -
3:13 - 3:16after coming into contact with air—
-
3:16 - 3:20a defense mechanism to prevent
excessive blood loss after injury. -
3:20 - 3:25In 1914, researchers discovered
that the chemical sodium citrate -
3:25 - 3:31stopped blood coagulating by removing
the calcium necessary for clot formation. -
3:31 - 3:35Citrated blood could be stored
for later use— -
3:35 - 3:39the first step in making large scale
blood transfusions possible. -
3:39 - 3:46In 1916, a pair of American scientists
found an even more effective anticoagulant -
3:46 - 3:52called heparin, which works by
deactivating enzymes that enable clotting. -
3:52 - 3:54We still use heparin today.
-
3:54 - 3:55At the same time,
-
3:55 - 3:59American and British researchers
developed portable machines -
3:59 - 4:05that could transport donor blood
onto the battlefields of World War I. -
4:05 - 4:07Combined with
the newly-discovered heparin, -
4:07 - 4:11medics safely stored
and preserved liters of blood, -
4:11 - 4:16wheeling it directly onto the battlefield
to transfuse wounded soldiers. -
4:16 - 4:21After the war, this crude portable box
would become the inspiration -
4:21 - 4:25for the modern-day blood bank,
a fixture of hospitals around the world.
- Title:
- How does blood transfusion work? - Bill Schutt
- Speaker:
- Bill Schutt
- Description:
-
View full lesson: https://ed.ted.com/lessons/how-does-blood-transfusion-work-bill-schutt
In 1881, doctor William Halsted rushed to help his sister Minnie, who was hemorrhaging after childbirth. He quickly inserted a needle into his arm, withdrew his own blood, and transferred it to her. After a few uncertain minutes, she began to recover. What made this blood transfusion successful? Bill Schutt explains the history of the life-saving procedure.
Lesson by Bill Schutt, directed Hype CG.
- Video Language:
- English
- Team:
- closed TED
- Project:
- TED-Ed
- Duration:
- 04:28
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