What Are Anesthetics? Key Concepts, Uses & Examples in Biology
In the middle ages, any type of surgery was very painful and tiring. Then with the discovery of anesthetics, the pain of the patient has been greatly reduced. Anesthetics play a very important role in most surgical procedures. Upon the dosage, the anesthetics tend to numb a part of the body or the whole body itself. The anesthetics usually act on the nerves and affect the central nervous system and the spinal cord. Anesthetics can be administered in several ways. It mainly includes general anesthesia, local or regional anesthesia, and Monitored Anesthesia Care (MAC).In this article, we’ll read about the various types of anesthetics.
General Anesthesia
The process of administration of anesthetics is basically the anesthesia meaning. General anesthesia is a process in which the body is put into a medically induced state of coma. After the administration of general anesthesia, the patient will not feel or remember anything about the surgery and potentially gets channeled into a state of “deep sleep”. The purpose of general anesthesia includes unconsciousness, analgesia, amnesia, immobility, and paralysis. General anesthetics like halothane tend to affect the central nervous system. The cerebral cortex, thalamus, reticular activating system, and spinal cord are the most affected by general anesthesia. The administration of general anesthetics can be divided into four stages based on dosage and purpose.
The administration of general anesthetics can be divided into four stages based on dosage and purpose. The stages are -
Stage 1- This stage is also known as the “induction stage”.This is the period between administration of anesthetics and falling into a state of unconsciousness.
Stage 2 - This stage is known as the “excited” stage. It is determined as the time between falling into unconsciousness and the experience of the delirious activity. The heart rate and the respiratory rate of the patient may show some irregularities.
Stage 3 - The third stage is known as the “ surgical” stage. The stage involves the loss of laryngeal and light reflexes. Shallow abdominal respiration occurs along with intercostal paralysis.
Stage 4 - This is the stage of “ overdose “. The patient may suffer from severe cardiovascular and respiratory problems. This can be lethal.
Local Anesthesia
Local anesthesia is a procedure to induce the absence of pain in a specific part of the body. It aims at local analgesia. Even though local anesthesia is only meant to induce local analgesia but the other local senses may be affected as well. Local anesthesia is used for a smaller part of the body such as a tooth. Regional anesthesia on the other hand affects a larger part such as a leg or an arm. Whereas conduction anesthesia consists of various local and regional anesthetic techniques. Sometimes local anesthetics are injected into a nerve trunk thus blocking the nerve. Hence it is also known as nerve block anesthesia.
Regional anesthesia is of various types depending upon their place of administration. Namely-
Axillary nerve block
Femoral nerve block.
Ankle block.
Bier block.
Interscalene nerve block.
MAC Anesthesia
Monitored Anesthesia Care or MAC anesthesia is a type of anesthesia in which the patient is aware but in a highly relaxed state. The dosage is decided by the anesthetist depending on the patient’s health. Propofol, midazolam, and fentanyl are some of the medications used for monitored anesthesia care. MAC anesthesia is mainly used for smaller surgeries like endoscopy, bronchoscopy, dental procedures, and eye surgeries. Apart from minor surgeries, MAC is used for diagnostic and therapeutic purposes. Presently MAC constitutes about 10%-30% of choice for all surgical procedures.
Did You Know?
Humphrey Davy discovered the anesthetic properties of nitrous oxide back in 1799 but the implications of his findings in surgery were ignored.
William Morton operated on a neck tumor by using ether as a general anesthetic in October 1846 to prove to the world that general anesthesia was a practical proposition.
Modern inhalation anesthetics like halothane and trichloroethylene are administered by mixing them with nitrogen oxide and oxygen.
FAQs on Anesthetic: Types, Mechanisms, and Biological Impact
1. What is an anesthetic?
An anesthetic is a type of drug used in medicine to induce a temporary loss of sensation or awareness. Its primary purpose is to prevent pain during surgical operations and other medical procedures. By affecting the nervous system, it allows patients to undergo procedures without feeling discomfort or distress.
2. What is the difference between the terms 'anesthetic' and 'anesthesia'?
The terms are related but distinct. An anesthetic refers to the actual drug or substance (e.g., propofol, lidocaine) that causes the loss of sensation. Anesthesia, on the other hand, is the medical state or process of using these drugs to induce a controlled, temporary loss of sensation or consciousness. In short, an anesthetic is the tool, and anesthesia is the result.
3. What are the major types of anesthesia used in medical procedures?
Anesthesia is broadly classified into three main types based on its effect on the body:
General Anesthesia: Induces a state of complete unconsciousness, affecting the entire body. The patient is asleep and has no memory of the procedure. It is used for major surgeries like heart or organ transplants.
Regional Anesthesia: Blocks pain in a large area of the body, such as a limb or the lower half of the body. The patient remains awake. Examples include epidurals used during childbirth and nerve blocks for arm or leg surgery.
Local Anesthesia: Numbs a small, specific part of the body for a minor procedure. It is the most common type, used for procedures like dental fillings or stitching a small cut.
4. How do anesthetics work at a biological level to block pain?
Anesthetics function by interrupting nerve signals. Local anesthetics work by blocking the sodium channels in the membranes of neurons (nerve cells) in a specific area. This action prevents the nerves from generating and transmitting electrical impulses, so pain signals from that area cannot reach the brain. General anesthetics are more complex; they act on the central nervous system (CNS), primarily the brain, depressing its activity to induce unconsciousness and block the processing of sensory information.
5. What are some common examples of anesthetic drugs?
Anesthetic drugs are diverse and chosen based on the type of anesthesia required. Common examples include:
For General Anesthesia: Propofol, Etomidate (intravenous); Sevoflurane, Halothane (inhaled).
For Local/Regional Anesthesia: Lidocaine, Bupivacaine, Ropivacaine.
6. In what situations is general anesthesia preferred over local or regional anesthesia?
The choice of anesthesia depends on the medical procedure's complexity, duration, and location. General anesthesia is typically preferred for:
Long and complex surgeries (e.g., open-heart surgery, neurosurgery).
Procedures that require the patient to be completely still and unconscious.
Operations on major internal organs in the chest or abdomen.
When a patient is extremely anxious or unable to cooperate.
In contrast, local or regional anesthesia is suitable for shorter, less invasive procedures on specific body parts.
7. Why is it essential to monitor a patient's vital signs during an operation under anesthesia?
Monitoring is critical because anesthetics, especially general anesthetics, suppress the central nervous system, which controls vital bodily functions. Anesthesiologists continuously track heart rate, blood pressure, breathing, oxygen saturation, and temperature to ensure the patient remains stable and safe. This constant monitoring allows the medical team to detect any adverse reactions immediately and adjust the anesthetic dosage in real-time, preventing complications and ensuring the patient's well-being throughout the surgery.
8. Are anesthetics and painkillers the same thing?
No, they are not the same, although both deal with pain. Anesthetics block all sensations, including pain, touch, and temperature, often causing numbness or unconsciousness. They are used *during* a procedure to make it painless. Painkillers, also known as analgesics (e.g., Paracetamol, Morphine), specifically target and reduce the sensation of pain without causing a loss of other senses or consciousness. They are typically used to manage pain *after* an injury or procedure.
