Lecture_6a

Anesthesia Overview

Historical Context

• General anesthesia has roots in ancient medical practices, as recorded by:

  • Ancient Sumerians

  • Babylonians

  • Assyrians

  • Egyptians

  • Indians

  • Chinese

Key Historical Figures in Anesthesia

• Hua Tuo (circa AD 200)

  • Renowned Chinese surgeon from the 2nd century AD.

  • Known for performing surgeries under general anesthesia.

  • Developed a potion called mafeisan from wine and herbal extracts.

  • Administered this oral anesthetic for major surgeries, like resection of gangrenous intestines.

  • Induced unconsciousness and partial neuromuscular blockade.

  • His clinical knowledge and the exact mafeisan formula were lost upon his death.

  • Surgical practices declined post-Hua Tuo due to Confucian beliefs regarding body integrity.

• Hanaoka Seishū (1760 - 1835)

  • A Japanese surgeon of the Edo period.

  • Pioneered the use of general anesthesia using tsūsensan, inspired by Hua Tuo's mafeisan.

  • Developed tsūsensan through research and experimentation with various plants.

  • Possible ingredients included hashish, bhang, shang-luh, or opium.

  • Became well-known for painless surgeries, performing over 150 operations for breast cancer.

  • His innovative techniques influenced future surgical practices.

• Crawford Long (1815 - 1878)

  • An American surgeon credited with the first use of inhaled ether as anesthesia.

  • Observed the effects of diethyl ether on patients, leading to its use on March 30, 1842.

  • Administered ether via a towel for surgeries, including tumor removals and childbirth.

  • First published findings in 1849, following William T. G. Morton’s public demonstration of ether anesthesia in 1846.

Nitrous Oxide and Other Anesthetics

• Discovered in 1793 by Joseph Priestly, nitrous oxide (N2O) has been used for over 150 years.

• Horace Wells pioneered its use in dentistry.

• William T. G. Morton publicly demonstrated inhaled ether in 1846, overshadowing Long's earlier work.

Development of Intravenous Anesthesia

• Began in 1656 with Wren utilizing a goose quill for injections.

• Advancements in the 1800s with the hollow needle (1843) and hypodermic syringe (1853).

• Early 1900s: Various drugs were administered intravenously for sedation.

• In 1909, Krawkow demonstrated the anesthetic properties of hedonal.

• Despite its potential, hedonal had limitations regarding application.

• Rapid development of barbiturates began in the 1920s, notably thiopental, which became a standard for anesthesia.

General Anesthesia Mechanisms

• General anesthetics induce:

  • Loss of consciousness

  • Analgesia

  • Loss of reflexes

  • Muscle paralysis (in some cases)

• Mechanisms are not entirely understood but are vital for surgical procedures.

Types of Anesthesia

• General Anesthesia

  • Delivered via inhalation or non-inhalation methods

  • Includes intravenous, intramuscular, and intraosseous routes.

• Local Anesthesia

  • Acts on peripheral receptors with minimal systemic effects.

  • Employed primarily for minor procedures (e.g., dental work).

Classification of Anesthetic Agents

• Inhaled Anesthetics

  • Requires specialized equipment for delivery.

  • Usually slower onset than intravenous anesthetics.

• Intravenous Anesthetics

  • No special equipment needed for delivery.

  • Faster onset of action relative to inhaled agents.

Modern Local Anesthetic Development

• Cocaine, the first local anesthetic from the coca bush, used in 1884.

• Procaine (1904) and Tetracaine (1930) followed.

• Lofgren developed Lidocaine in 1943, greatly reducing allergic reactions.

• Subsequent amide anesthetics improved potency and duration.

Spinal Anesthesia

• Used since the late 19th century to numb the lower body.

• Initially involved cocaine, now utilizes Lidocaine, Bupivacaine, and Ropivacaine.

• Techniques and medications have evolved, with minor side effects reported.

Conclusion

• Anesthesia has significantly evolved over the centuries, enhancing surgical techniques and patient safety.

• Ongoing research continues to aid in developing safer, more effective anesthetic agents.

Anesthesia Overview

Historical Context

• General anesthesia has roots in ancient medical practices, as recorded by:

  • Ancient Sumerians

  • Babylonians

  • Assyrians

  • Egyptians

  • Indians

  • Chinese

Key Historical Figures in Anesthesia

• Hua Tuo (circa AD 200)

  • Renowned Chinese surgeon from the 2nd century AD.

  • Known for performing surgeries under general anesthesia.

  • Developed a potion called mafeisan from wine and herbal extracts.

  • Administered this oral anesthetic for major surgeries, like resection of gangrenous intestines.

  • Induced unconsciousness and partial neuromuscular blockade.

  • His clinical knowledge and the exact mafeisan formula were lost upon his death.

  • Surgical practices declined post-Hua Tuo due to Confucian beliefs regarding body integrity.

• Hanaoka Seishū (1760 - 1835)

  • A Japanese surgeon of the Edo period.

  • Pioneered the use of general anesthesia using tsūsensan, inspired by Hua Tuo's mafeisan.

  • Developed tsūsensan through research and experimentation with various plants.

  • Possible ingredients included hashish, bhang, shang-luh, or opium.

  • Became well-known for painless surgeries, performing over 150 operations for breast cancer.

  • His innovative techniques influenced future surgical practices.

• Crawford Long (1815 - 1878)

  • An American surgeon credited with the first use of inhaled ether as anesthesia.

  • Observed the effects of diethyl ether on patients, leading to its use on March 30, 1842.

  • Administered ether via a towel for surgeries, including tumor removals and childbirth.

  • First published findings in 1849, following William T. G. Morton’s public demonstration of ether anesthesia in 1846.

Nitrous Oxide and Other Anesthetics

• Discovered in 1793 by Joseph Priestly, nitrous oxide (N2O) has been used for over 150 years.

• Horace Wells pioneered its use in dentistry.

• William T. G. Morton publicly demonstrated inhaled ether in 1846, overshadowing Long's earlier work.

Development of Intravenous Anesthesia

• Began in 1656 with Wren utilizing a goose quill for injections.

• Advancements in the 1800s with the hollow needle (1843) and hypodermic syringe (1853).

• Early 1900s: Various drugs were administered intravenously for sedation.

• In 1909, Krawkow demonstrated the anesthetic properties of hedonal.

• Despite its potential, hedonal had limitations regarding application.

• Rapid development of barbiturates began in the 1920s, notably thiopental, which became a standard for anesthesia.

General Anesthesia Mechanisms

• General anesthetics induce:

  • Loss of consciousness

  • Analgesia

  • Loss of reflexes

  • Muscle paralysis (in some cases)

• Mechanisms are not entirely understood but are vital for surgical procedures.

Types of Anesthesia

• General Anesthesia

  • Delivered via inhalation or non-inhalation methods

  • Includes intravenous, intramuscular, and intraosseous routes.

• Local Anesthesia

  • Acts on peripheral receptors with minimal systemic effects.

  • Employed primarily for minor procedures (e.g., dental work).

Classification of Anesthetic Agents

• Inhaled Anesthetics

  • Requires specialized equipment for delivery.

  • Usually slower onset than intravenous anesthetics.

• Intravenous Anesthetics

  • No special equipment needed for delivery.

  • Faster onset of action relative to inhaled agents.

Modern Local Anesthetic Development

• Cocaine, the first local anesthetic from the coca bush, used in 1884.

• Procaine (1904) and Tetracaine (1930) followed.

• Lofgren developed Lidocaine in 1943, greatly reducing allergic reactions.

• Subsequent amide anesthetics improved potency and duration.

Spinal Anesthesia

• Used since the late 19th century to numb the lower body.

• Initially involved cocaine, now utilizes Lidocaine, Bupivacaine, and Ropivacaine.

• Techniques and medications have evolved, with minor side effects reported.

Conclusion

• Anesthesia has significantly evolved over the centuries, enhancing surgical techniques and patient safety.

• Ongoing research continues to aid in developing safer, more effective anesthetic agents.