Merlin Larson, MD (@merlinlarsonmd1) 's Twitter Profile
Merlin Larson, MD

@merlinlarsonmd1

Swede, wannabe Italian, Bad at classical guitar; anesthesiologist, Stanford and NIH trained. UCSF Faculty 30 years. Pupillometrist. Standard disclaimers.

ID: 1292220880571965440

calendar_today08-08-2020 22:07:36

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Merlin Larson, MD (@merlinlarsonmd1) 's Twitter Profile Photo

This apparatus was used by anesthetists in the 1870s. Mask, ether bottle and forceps. The forceps was used to intermittently pull the tongue forward. To solve that problem Guedel invented the rubber airway (1933) and his design has lasted unchanged for over 90 years

This apparatus was used by anesthetists in the 1870s.  Mask, ether bottle and forceps.  The forceps was used to intermittently pull the tongue forward. To solve that problem Guedel invented the rubber airway (1933) and his design has lasted unchanged for over 90 years
Merlin Larson, MD (@merlinlarsonmd1) 's Twitter Profile Photo

The old operating room at St Thomas Hospital in London was built in 1822. This painting depicts a typical surgery in that OR. Many patients died from the stress of surgery. It is noteworthy that ether was one of the drugs in the pharmacy of that hospital.

The old operating room at St Thomas Hospital in London was built in 1822.  This painting depicts a typical surgery in that OR.  Many patients died from the stress of surgery.  It is noteworthy that ether was one of the drugs in the pharmacy of that hospital.
Merlin Larson, MD (@merlinlarsonmd1) 's Twitter Profile Photo

History.com lists these important events from the year 1846: 1. US declares war on Mexico. 2. US gains control of lands below the 49th parallel from Great Britain. They do not mention the most important discovery in the history of medicine (Boston: Oct 16, 1846).

History.com lists these important events from the year 1846: 1. US declares war on Mexico. 2.  US gains control of lands below the 49th parallel from Great Britain.  They do not mention the most important discovery in the history of medicine (Boston: Oct 16, 1846).
Merlin Larson, MD (@merlinlarsonmd1) 's Twitter Profile Photo

A submission in the 2025 California Society of Anesthesiologist’s essay contest discusses the herbal based anesthetic used by Hanaoka Seishu in 1804, 42 years prior to the introduction of ether. Here is an artists rendition of the surgery.

A submission in the 2025 California Society of Anesthesiologist’s essay contest discusses the herbal based anesthetic used by Hanaoka Seishu in 1804, 42 years prior to the introduction of ether.  Here is an artists rendition of the surgery.
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The person who secures the airway during CPR can then assess midbrain function by using a portable pupillometer (image). See discussion in “A Practical Guide to Portable Pupillometry”.

The person who secures the airway during CPR can then assess midbrain function by using a portable pupillometer (image).  See discussion in “A Practical Guide to Portable Pupillometry”.
Merlin Larson, MD (@merlinlarsonmd1) 's Twitter Profile Photo

ChatGPT claims that general anesthesia blocks sensation and perception. But that is wrong. Measure the heart rate following the incision after induction of anesthesia with propofol. The increase in rate is sensation. The word anesthesia (without sensation) was poorly chosen.

ChatGPT claims that general anesthesia blocks sensation and perception.  But that is wrong.   Measure the heart rate following the incision after induction of anesthesia with propofol. The increase in rate is sensation.  The word anesthesia (without sensation) was poorly chosen.
Merlin Larson, MD (@merlinlarsonmd1) 's Twitter Profile Photo

What’s with the anti-science rhetoric? Progress takes time. Poisoned arrows (image) were a mystery to the early explorers. Today, modern relaxants are used in all major operations. If you need surgery, thank the many government grants that made anesthesia safe.

What’s with the anti-science rhetoric?  Progress takes time. Poisoned arrows (image) were a mystery to the early explorers. Today, modern relaxants are used in all major operations. If you need surgery, thank the many government grants that made anesthesia safe.
Merlin Larson, MD (@merlinlarsonmd1) 's Twitter Profile Photo

In this classic paper, Bernard described how the autonomic nervous system protects the “internal mileau” from changes in the external environment. Anesthetics interfere with many of these reflexes. Maintaining the “internal mileau” thus depends on the skill of the anesthetist.

In this classic paper, Bernard described how the autonomic nervous system protects the “internal mileau” from changes in the external environment.  Anesthetics interfere with many of these reflexes.  Maintaining the “internal mileau” thus depends on the skill of the anesthetist.
Merlin Larson, MD (@merlinlarsonmd1) 's Twitter Profile Photo

This chart shows the anesthetic deaths in England (1846 to 1950). It was constructed by W. Stanley Sykes, MD (1984-1961). Some of the deaths occurred under his care. He “burned out” of anesthesia mid 20th century in order to write medical history books and mystery novels.

This chart shows the anesthetic deaths in England (1846 to 1950).  It was constructed by W. Stanley Sykes, MD (1984-1961).  Some of the deaths occurred under his care. He “burned out” of anesthesia mid 20th century in order to write medical history books and mystery novels.
Merlin Larson, MD (@merlinlarsonmd1) 's Twitter Profile Photo

The word rumination stems from Latin word “ruminatus” …to chew over again. Rumination can rarely be the ruin of physicians that manage life threatening emergencies.

The word rumination stems from Latin word “ruminatus” …to chew over again.  Rumination can rarely be the ruin of physicians that manage life threatening emergencies.
Merlin Larson, MD (@merlinlarsonmd1) 's Twitter Profile Photo

See the anesthetist on the left with a brain, eyes, ears, and hands (Figure 26 from Faulkoner)? In a widely circulated article in Science (126:827-830, 1957), J.W. Bellville suggested replacing the anesthetist with a machine.

See the anesthetist on the left with a brain, eyes, ears, and hands (Figure 26 from Faulkoner)?  In a widely circulated article in Science (126:827-830, 1957), J.W. Bellville suggested replacing the anesthetist with a machine.
Merlin Larson, MD (@merlinlarsonmd1) 's Twitter Profile Photo

Can an anesthetist be technically skilled but scientifically stupid? Gardner Q. Colton (1814-1898) administered 121,709 nitrous oxide anesthetics (dental surgeries) without a death. He was not doctor and believed that 100% nitrous oxide delivered more oxygen than room air.

Can an anesthetist be technically skilled but scientifically stupid?   Gardner Q.  Colton (1814-1898) administered 121,709 nitrous oxide anesthetics (dental surgeries) without a death.  He was not doctor and believed  that 100% nitrous oxide delivered more oxygen than room air.
Merlin Larson, MD (@merlinlarsonmd1) 's Twitter Profile Photo

75 years from now, will anesthesiologists read our case reports and find them as bizarre as this one reported by Guedel in his book “Inhalation Anesthesia” from 1937?

75 years from now, will anesthesiologists read our case reports and find them as bizarre as this one reported by Guedel in his book “Inhalation Anesthesia” from 1937?
Merlin Larson, MD (@merlinlarsonmd1) 's Twitter Profile Photo

Every decade has new innovations for the anesthesiologist. In the 1940s, the innovation was tracheal intubation. Macintosh and Mushin discussed tracheal intubation and presented the problem with small ET tubes (see image) in their book “Physics for the Anesthetist” (1947).

Every decade has new
innovations for the anesthesiologist.  In the 1940s, the innovation was tracheal intubation.  Macintosh and Mushin discussed tracheal intubation and presented the problem with small ET tubes (see image) in their book “Physics for the Anesthetist” (1947).
Merlin Larson, MD (@merlinlarsonmd1) 's Twitter Profile Photo

Pontius Pilate was the Governor of Judea from 26-36 CE. He is known for the phrase “What is Truth”. In 1860, did Dr. W. K. Atkinson speak the truth about the discovery of anesthesia? (Image: A Calculus of Suffering, by M. S. Pernick, 1985). …(See Tweet 9/4/21, about Truth).

Pontius Pilate was the Governor of Judea from 26-36 CE.  He is known for the phrase “What is Truth”.  In 1860, did Dr. W. K. Atkinson speak the truth about the discovery of anesthesia?   (Image: A Calculus of Suffering, by M. S. Pernick, 1985). …(See Tweet 9/4/21, about Truth).
Merlin Larson, MD (@merlinlarsonmd1) 's Twitter Profile Photo

Opioids do not depress the pupillary light reflex (image). See further discussion in “A Practical Guide to Portable Pupillometry”.

Opioids do not depress the pupillary light reflex (image).  See further discussion in “A Practical Guide to Portable Pupillometry”.
Merlin Larson, MD (@merlinlarsonmd1) 's Twitter Profile Photo

This year is the 250th anniversary of the discovery of oxygen by Antoine Lavoisier. Image: The opening page of this landmark publication. In 1794 Lavoisier was executed during the “Reign of Terror” following the French Revolution.

This year is the 250th anniversary of the discovery of oxygen by Antoine Lavoisier.  Image: The opening page of this landmark publication.  In 1794 Lavoisier was executed during the “Reign of Terror” following the French Revolution.
Merlin Larson, MD (@merlinlarsonmd1) 's Twitter Profile Photo

Christison’s classic book (1839) on poisons claimed that leeches died when used as treatment for opium toxicity (image). But leeches absorb oxygen through the skin- they don’t breathe. Leeches have opioid receptors that cause paralysis - they might look dead but are just fine.

Christison’s classic book (1839)  on poisons claimed that leeches died when used as treatment for opium toxicity (image). But leeches absorb oxygen through the skin- they don’t breathe.  Leeches have opioid receptors that cause paralysis - they might look dead but are just fine.
Merlin Larson, MD (@merlinlarsonmd1) 's Twitter Profile Photo

The citizens of Edinburgh have contributed ideas about how we now think about labor pain. In 1591, Effie Macalyean was executed for trying to relieve the pain of childbirth (Edinburgh). Generations later (1846), James Simpson promoted the same idea in Edinburgh, using chloroform.

The citizens of Edinburgh have contributed ideas about how we now think about labor pain. In 1591, Effie Macalyean was executed for trying to relieve the pain of childbirth (Edinburgh). Generations later (1846), James Simpson promoted the same idea in Edinburgh, using chloroform.