inhalational agents: history and MAC Flashcards
what was surgery like prior to the invention of anesthetic agents?
- surgery was a last, and desperate, resort
- attempted a wide range of plants (marijuana, belladonna, jimsonweed), hypnosis, and knocking unconscious
- alcohol: levels needed caused N/V, death rather than sleep
- opium: strong analgesic but not enough to completely blunt sympathetic stimulation response
when is anesthesiology considered to have begun?
1842 w/ the discovery of three agents:
- nitrous oxide
- ether
- chloroform
when and by whom was chloroform discovered?
- 1847
- Dr. James Simpson, British obstetrician
who is Dr. John Snow?
first to devote his practice to the administration of anesthetics
-administered chloroform to Queen Victoria during the birth of Prince Leopold
who may have first discovered ether?
- Dr. Crawford W. Long
- from Georgia
- first to conceive the use of ether to alleviate pain of surgery, but did not publish his finding
- not until others took credit for it, claimed he had used since 1841 for minor operations
who first suggested the use of nitrous oxide for anesthesia?
- Horace Wells
- Connecticut Dentist who had used nitrous oxide successfully during tooth extraction
- tried to demonstrate technique to a group of Harvard Medical students, but pt. cried out
- he did not understand the lack of potency of nitrous oxide
- called “humbug” and driven out of Boston; became addicted to chloroform and committed suicide 1848
- 1864 finally credited by American dental assoc. and American medical assoc. w/ discovery
who gained recognition first for use of ether?
William T.G. Morton
- dentist and colleague of Wells (N2O)
- administered ether to Gilbert Abbott at Mass. General, marking first successful public demonstration
- October 16, 1846- “Ether Day”
- he called it letheon but later was forced to reveal it was simply diethyl ether
- able to provide anesthesia during Civil War
what did Morton use to administer the ether?
he made a glass inhaler and placed an ether soaked sponge
describe the event on ether day
- October 16, 1846
- William T.G. Morton, Boston dentist, demonstrated the use of ether during surgery
- used a glass inhaler containing an ether-soaked sponge to administer the anesthetic to Gilbert Abbott
- Abbott had a vascular tumor removed by widely known surgeon, John Collins Warren, MD
- Abbott woke up and denied feeling any pain
- Warren exclaimed of Morton, “gentlemen, this is no humbug!”
- known as the “greatest gift ever made to suffering humanity”
Who was Charles Jackson, MD?
- Boston physician and chemist who advised Morton to use ether and claimed to have a large part in the discovery
- pressed claims for credit all the way to Congress, which upheld Morton as discoverer
- history of making such claims: also claimed Samuel Morse stole his idea for inventing the telegraph
who is known as the first anesthesiologist and what was his first use?
- Dr. John Snow
- first administered chloroform to Queen Victoria on April 7, 1853
who proposed the use of chloroform as an alternative to ether?
James Simpson, MD, an OB in Scotland
why were anesthetics meet religious opposition?
- thought to mock the curse of “primal sin”
- Genesis 3:16 “Unto a woman, He said, I will greatly multiply the sorrow and thy conception; in sorrow thou shalt bring forth children”
- Exodus 22:18 “Thou shalt no suffer a witch to live” thought a witch couldn’t handle pain of labor
who finally endorsed the use of anesthetics, rebuffing the minority of priests and ministers who condemned OB anesthesia?
Archbishop of Centerbury, John Bird Summer (1780-1862)
who coined the term “anaesthesia”?
- Oliver Wendell Holmes, Sr. (1809-1894)
- from the Greek word “anaisthesia”, meaning “lack of sensation” (1846)
what objections to anesthesia took place?
- American Medical Association (1848)
- vice president of AMA, John P. Harrison (1849): “pain is curative, the actions of life are maintained by it…”
- Henry Ward Beecher (famous preacher): “the less pain, the less life capacity; the less pain power, the less life power”
- Pennsylvania Hospital prohibited use until 1853
describe the ideal anesthetic
- non flammable
- easily vaporized at ambient temperature
- potent
- low blood solubility to assure rapid induction and emergence
- minimal metabolism
- compatible w/ epinephrine
- skeletal muscle relaxation
- suppresses excessive SNS activity
- not irritating to airways
- bronchodilation
- absence of excessive myocardial depression
- absence of cerebral vasodilation
- absence of hepatic and renal toxicity
what were the issues w/ ether?
- flammability
- prolonged induction
- delayed emergence
- PONV high incidence
what brought the development of “modern” inhalation agents?
- with the development of the atomic bomb came discoveries in fluorine chemistry
- after 1950, all introduced agents (except ethyl vinyl ether) contains fluorine
- first fluroxene (limited use d/t PONV), then halothane
what were the advantages and disadvantages of halothane?
advantages
- non flammable
- less pungent
- less soluble
- decreased toxicity
disadvantages: decreased CO and increased arrhythmias (hepatotoxicity)
describe halothane structure
- not an ether, no oxygen
- an ethane, 2 carbon chain
- an alkane
