Anesthesia has been around for nearly 200 years, and it has become increasingly commonplace. Nearly anyone who has had a cavity filled has experienced local anesthesia, and anyone who has had surgery, from getting their tonsils out to their hip replaced, has used general anesthesia. While using anesthesia for pain-free surgery is now an expectation this wasn’t always the case. The invention of anesthesia has revolutionized medicine and allowed doctors to perform life-saving surgeries.
What is anesthesia?
The word anesthesia first entered medical vocabulary in 1846, when Oliver Wendell Holmes, Sr. saw a public demonstration of ether being used at Massachusetts General Hospital on a patient. The term refers to a person’s inability to sense touch. Prior to the invention of anesthesia, surgeries were completed with a patient awake and feeling every incision, or, more commonly, a life-saving procedure was not conducted, and the person died. Anesthesia was a welcome addition to the world of medical practice, and it with newer developments, has become safer.
Anesthesia consists of three main components that can be used individually or all together. The components are:
- Analgesia: Reduction or elimination of pain
- Amnesia: Experienced only temporarily and can include unconsciousness
- Muscle relaxation
The effects of anesthesia vary based on the type of anesthesia a person receives.
Types of anesthesia
Two types of anesthesia have emerged over time: local anesthesia and general anesthesia. Local anesthesia is used when only a small area needs to be anesthetized. Examples include Novocain, which is used during dental procedures such as cavity filling or root canals. Local anesthesia also can be used for smaller surgeries, such as dermatology procedures, or for procedures such as repairing a broken bone or stitching a deep cut. It anesthetizes only a certain area of the body, hence the term “local”. General anesthesia is used for major surgeries, such as heart surgery, joint replacements, and surgeries designed to remove tumors or other cancerous growths. In simple terms, general anesthesia “knocks out” a person or “puts them under.” It essentially causes a state where a person is unconscious and cannot feel any pain or have any memory of the time while under the influence of general anesthesia.
How does anesthesia work?
Anesthesia is something many people have experienced, but few people know the science behind it. Local anesthesia and general anesthesia work differently in the body, and they have different impacts.
Local anesthesia typically blocks the nerves that transmit impulses to pain centers in a person’s central nervous system by obstructing a particular channel in the nerve cell. Think of nerve cells as a parking lot. Local anesthesia parks in a particular spot normally reserved for pain, which means the chemicals carrying a message of pain cannot park there and must continue circling around the block. That results in the inability to feel pain in specific areas of the body that a healthcare provider has targeted with local anesthesia.
General anesthesia is a bit less well understood. General anesthesia results in a person being unable to sense pain and even impact basic functions such as breathing, heart rate, and blood pressure. The majority of general anesthesia is inhaled, and new forms of it are structured quite similarly to ether, which was the original anesthetic. Scientists know that general anesthesia uses a similar concept as local anesthesia, which is blocking the transmission of chemicals from a nerve to a receptor causing the amnestic state. A recent study found that general anesthesia interacts with a small area of the brain responsible for controlling functions such as sleep. This new understanding could lead to improved anesthesia drugs in the future.
What to expect
As a person prepares to undergo a treatment that will require anesthesia, it is important to understand what to expect. For a procedure that requires local anesthesia, the healthcare provider will inject the local anesthesia directly in or near the area that needs to be anesthetized. Local anesthesia typically takes several minutes to take effect. General anesthesia is more complex as the entire body is affected. A medical doctor called an anesthesiologist will administer general anesthesia, which is typically delivered in an inhalable or injectable. General anesthesia takes effect immediately, with the patient feeling tired within a few seconds. General anesthesia can slow down breathing or lower blood pressure, and the anesthesiologist will monitor the patient to ensure their vital signs are being maintained.
Written by Sheena McFarland
