Chapter 11: Inhalation Sedation - Historical Perspective

Question 1

Who discovered N2O-O2? and when?

Answer 1

Joseph Priestly in the late 18th century (1771-1777)

Question 2

What is Sir Humphrey Davy known for?

Answer 2

Chronic use of N2O

Question 3

Who chronically used N2O? and in what year?

Answer 3

Sir Humphrey Davy, in 1798

Question 4

What were the sensations Sir Humphrey Davy got from N2O?

Answer 4

pleasure, euphoria, felt like laughing, “most voluptuous sensations”, “ideal existence”, “overwhelming joy”

Question 5

In 1795, who did Davy become an apprentice to and what was their career path?

Answer 5

to the surgeon J.B. Borlase

Question 6

Who experimented with N2O and the effects of its inhalation at the age of 17?

Answer 6

Sir Humphrey Davy

Question 7

What did Sir Humphrey Davy experience while using N2O?

Answer 7

He experienced decreased pain from a toothache while using N2O; 1st indication of anesthetic properties of N2O.

Question 8

Describe things that happened during early surgery?

Answer 8

• Many deaths from infection
• Pain control was problematic
• Mostly dental extractions, amputations, incision
  and drainage of abscesses
• Usually fast less than 90 sec
• Most important medical advantage was suture
• Suicide vs. operation without pain control
• Torture

Question 9

What did Colton do in 1844?

Answer 9

demonstrated effects of N2O

Question 10

Who was Colton?

Answer 10

An itinerant medical school dropout from Columbia University. He travelled around the the countryside and presented his show of new scientific and quasi-scientific discoveries to eager audiences. In this show N2O was demonstrated and discussed. He had volunteers from the audience participate.

Question 11

How did Dr. Horace Wells and Professor Colton meet?

Answer 11

Dr. Horace Wells was in Professor Colton’s audience the particular evening he was demonstrating N2O in Hartford, CT.

Question 12

What was Wells’ profession?

Answer 12

a dentist

Question 13

Who else besides Wells’ was in the audience at Professor Colton’s demonstration?

Answer 13

a store clerk named Samuel Cooley

Question 14

What happened to Cooley at Colton’s demonstration?

Answer 14

-Cooley volunteered to receive N2O. He breathed in 100% N2O and quickly became intoxicated and was running about the stage. While running he hit his leg on the side of the table quite hard but didn’t notice. He was oblivious to his injury. His skin had been broken and he was bleeding but there was no indication that Cooley either felt discomfort or was even aware of the injury. Wells spoke with Cooley after the incident and confirmed that he had been unaware of that injury

Question 15

What did Dr. John Riggs do to Dr. Wells?

Answer 15

He extracted his wisdom tooth. After recovering from the effects of the N2O, Wells stated that he had been totally unaware of the procedure and there had been asbolutely no pain associated with it.

Question 16

What did Professor Colton teach Wells?

Answer 16

The process of manufacturing N2O and shortly thereafter began using it in his dental practice

Question 17

What happened to Wells after he started using N2O?

Answer 17

Wells demonstrated N2O pt moved and was thought to be having pain, Wells dismissed as charlatan. He used a newly developed inhaler and administered N2O through it to a student volunteer patient. As the patient lapsed into unconsicousness, Wells had to remove the inhaler, pick up his instruments and attempt to extract the volunteer’s infected tooth. During the extraction attempt, the patient cried out. The audience assumed that the procedure had failed. They booed him and forced him to leave the demonstration hall. Upon awakening the volunteer didn’t remember crying out and had no memory of the extraction.

Question 18

What is biologic variability?

Answer 18

people respond differently when given the same dose of a drug. this concept is illustrated with the bell-shaped or normal distribution curve

Question 19

What did Wells’ become addicted to? How and why did Wells’ life end?

Answer 19

He became addicted to chloroform. In 1848, he took a vial of sulfuric acid and threw it on a prostitute who earlier had damaged his clothes. Several days after Wells had inhaled some chloroform, he returned alone to Broadway in New York and while under the influence of the chloroform he threw sulfuric acid at two other prostitutes. He was arrested and placed in jail for these acts and then took his own life.

Summary:

• Wells abused chloroform
• Went crazy and threw acid on prostitute
• 1848 prison
• Committed suicide in prison

Question 20

Who is the founder of anesthesia?

Answer 20

Wells - Wells received later honors as the primary discoverer of anesthesia

Question 21

When was N2O reintroduced and by who?

Answer 21

in 1863 by Colton, in New Haven, CT

Question 22

What was Colton’s track record with N2O?

Answer 22

He spent 33 years extracting teeth under N2O. With 193,000 patients and no recorded fatalities (safety record). After this it became the most commonly used inhalation anesthetic.

Question 23

Who was William. T. G. Morton (1819-1868)?

Answer 23

He learned of the idea of inhalation anesthesia from Wells. He was a student of dentistry and then an associate in dental practice in Hartford. He then enrolled in med school at Harvard.

Question 24

What did Morton experiment with?

Answer 24

Ether. He was a member of the audience at Colton’s demonstration and thought a more effective anesthetic gas was required so he began to experiement with ether.

Question 25

Why was Morton well-received compared to Wells?

Answer 25

Because Morton was a physician and Wells was a dentist.

Question 26

Who was James Young Simpson? (1811-1870)

Answer 26

An obstetrician who experimented with chloroform (perchloride of formyl). They found that chloroform worked well and began using it as a means of alleviating pains of childbirth

Question 27

Who is Dr. Edmund W. Andrews (1824-1904) and what is he known for?

Answer 27

he was a physician born in Vermont and was one of the founders of the Chicago Medical College, now known as Northwestern School of Medicine. His major claim to fame was the addition of 20% of O2 to N2O. He claimed that this combination was safer and more pleasant than any anesthetic mixture then known.

Question 28

What was Andrews’ recommendation? Year 1868

Answer 28

Adding 4:1 N2O:O2. aka 80% N2O: 20% O2

Question 29

What did Paul Bert do in 1868?

Answer 29

He developed equipment to deliver N2O to patients. In 1868 he wrote that the use of 100% N2O for more than 2 minutes would bring about signs and symptoms of asphyxia. Bert designed an apparatus capable of delivering 25% O2 and 75% N2O.

Question 30

What happened in the twenieth century?

Answer 30

In 1910, E. I. McKesson, MD introduced the first intermittent-flow machine with accurate percentage control for N2O-O2. McKesson soon became the undisputed international authority on N2O anesthesia and a leader in its development.

Question 31

When was nitrous beginning to become more frequently used?

Answer 31

in the 1950s and 1960s it was becoming more frequently used in dentistry

Question 32

Why is nitrous used in GA?

Answer 32

it is commonly used in general anesthesia as a way to provide rapid induction of more potent agents

Question 33

What % of general dentists use N2O?

Answer 33

56% of general dentists use N2O/O2

Question 34

What % of oral surgeons use N2O?

Answer 34

85% of oral surgeons use N2O/O2

Question 35

What % of pediatric dentists use N2O?

Answer 35

88% of pediatric dentists use N2O/O2

Question 36

Define Pain

Answer 36

Pain is an unpleasant sensory or emotional experience arising from actual or potential tissue damage. The experience includes the perception of an uncomfortable stimulus and the response to that perception

Question 37

What’s the objective of pain?

Answer 37

Alert CNS to potential tissue damage

Question 38

What reverses the actions of opioids, ketamine and N2O?

Answer 38

Naloxone Hydrochloride

Question 39

Define anxiety

Answer 39

A nonspecific feeling of apprehension, worry, uneasiness, or dread, the source of which may be vague or unknown. A normal reaction when one’s body, lifestyle, values, or loved ones are threatened

Question 40

Define Fear

Answer 40

A feeling of fright or dread related to an identifiable source recognized by the individual

Question 41

Define Phobia

Answer 41

Any persistent and irrational fear of something specific, such as an object, activity, or situation that results in avoidance or desire to avoid the feared stimulus

Question 42

Continuum of Depth of Sedation

Answer 42

• Minimal sedation-anxiolysis
• Moderate sedation-analgesia
• Deep sedation-analgesia
• General anesthesia

Question 43

Definition of Minimal Sedation

Answer 43

A drug induced state during which patients respond normally to verbal commands. Although cognitive function and coordination may be impaired, ventilatory, and cardiovascular functions are unaffected.
- When administering N2O, minimal sedation is accomplished when concentrations are less than 50%

Question 44

Definition of Moderate Sedation

Answer 44

A drug-induced depression of consciousness during which
patients respond purposefully to verbal commands, either
alone or accompanied by light tactile stimulation. no
interventions are required to maintain a patent airway, and
spontaneous ventilation is adequate.
- Cardiovascular function is usually maintained.
- Moderate sedation is/may be achieved when N2O
concentrations are greater than 50%.

Question 45

Definition of Deep Sedation

Answer 45

• A drug induced depression of consciousness during
  which patients cannot be easily aroused but respond
  purposefully following repeated or painful
  stimulation. The ability to independently maintain
  ventilatory function may impaired. Patients may
  require assistance maintaining a patent airway, and
  spontaneous ventilations may be inadequate.
  
  • Cardiovascular function is usually maintained

Question 46

Definition of General Anesthesia

Answer 46

• A drug-induced loss of consciousness during which patients are not arousable, even by painful stimulation. The ability to independently maintain ventilatory function is often impaired. patients often require assistance in maintaining a patent airway, and positive pressure ventilation may be required because of depressed spontaneous ventilation or drug-induced depression of neuromuscular function.
• Cardiovascular function may be impaired.
• With N2O/O2 it is difficult to reach the appropriate plane for performing a surgical procedure; however, although difficult it is possible to render a patient unconscious using N2O/O2