Anesthesia

Main

Anesthesia is a medical intervention that prevents patients from feeling pain during surgical procedures, diagnostic tests, and other medical treatments. It involves the use of anesthetic drugs to induce a temporary loss of sensation or awareness.

How anesthesia works:

1. Administration of anesthetic drugs: Anesthetics are given through injection, inhalation, or topical application.

2. Anesthetic drugs interact with the central nervous system: They bind to receptors in the brain and spinal cord.

3. Suppression of nerve signals and brain activity: This interaction blocks the transmission of pain signals and reduces overall brain function.

4. Induction of unconsciousness, pain relief, or both: Depending on the type and dose of anesthetic, the patient may experience a loss of consciousness, pain relief, or a combination of both.

Types of anesthesia:

• General anesthesia: Renders the patient completely unconscious and unable to feel pain, often used for major surgeries.

• Local anesthesia: Numbs a specific area of the body, allowing the patient to remain awake during minor procedures.

• Regional anesthesia: Blocks pain in a larger region of the body, such as an arm or leg, by targeting specific nerve clusters.

• Sedation: Relaxes the patient and reduces anxiety, often used in combination with local or regional anesthesia.

Anesthesia can be dangerous if not administered properly or if the patient has certain risk factors such as obesity, sleep apnea, or heart disease. Complications may include allergic reactions, breathing problems, nausea and vomiting, or rarely, awareness during surgery.

Terms

• Analgesia: Pain relief without loss of consciousness.

• Central nervous system: The brain and spinal cord, which process and interpret sensory information and coordinate the body's responses.

Analogy

Anesthesia is like putting a computer into "sleep mode". Just as a sleeping computer is unresponsive to keyboard or mouse input, a person under anesthesia does not respond to surgical stimuli or feel pain. The anesthesiologist acts like the computer's power manager, inducing the "sleep state" and "waking up" the patient after the procedure is complete.

Misconception

Many people believe that general anesthesia is simply a deep sleep. However, while anesthesia does resemble sleep, it is a drug-induced state of unconsciousness that is much more profound. Under general anesthesia, you do not dream, your brain does not respond to pain signals, and your body's protective reflexes are suppressed.

History

1. 1846: First public demonstration of ether anesthesia by William T.G. Morton

2. 1884: Cocaine used as the first local anesthetic by Carl Koller

3. 1899: Spinal anesthesia introduced by August Bier

4. 1902: Barbiturates synthesized, later used for IV anesthesia induction

5. 1942: Curare introduced as a neuromuscular blocking agent

6. 1956: Halothane introduced as a potent inhaled anesthetic

7. 1980s-present: Development of shorter-acting, safer IV and inhaled anesthetics

How to use it

1. For a colonoscopy, you will receive sedation or "twilight" anesthesia. The anesthesiologist will administer medications through an IV to make you relaxed and drowsy, but you will still be breathing on your own.

2. If you are having a C-section, you will typically receive regional anesthesia in the form of a spinal or epidural block. This will numb you from the waist down, allowing you to remain awake during the birth of your baby.

3. For dental procedures like wisdom tooth extraction, your dentist or oral surgeon will use local anesthesia to numb your mouth. They will inject a numbing medication near the surgical site, ensuring you feel no pain during the procedure.

Facts

• Over 60,000 people in the US receive anesthesia each day.

• The word "anesthesia" comes from the Greek "an-" (without) and "aesthesis" (sensation).

• Anesthetic gases are exhaled unchanged by patients and contribute to greenhouse gas emissions. Avoiding unnecessarily high anesthetic flows can reduce the environmental impact by up to 5,000kg of CO2 per operating room per year.

• Anesthesia enables over 70 million surgical procedures to be performed safely each year in the US alone.

• Patients over 65 years old have a 35-50% risk of experiencing postoperative delirium after general anesthesia.