What is anesthesia?
Anesthesia is a medical procedure that puts you into a sleeping state and makes sure that you’re not feeling pain during surgery. Different types of medicines are used for this purpose. They are called anesthetics. Some of them are injected into veins (IV anesthetics), and others are in a gas form and delivered to a patient by breathing mask (inhalational anesthetics). The mechanisms by which these drugs affect the human body are diverse, and some are not fully understood. For example, local anesthetics numb nerves in the place where drugs are injected. In contrast, general anesthetics numb brain parts that are responsible for consciousness and the feeling of pain. A doctor who specializes in anesthesia (anesthesiologist), along with a trained nurse (certified registered nurse anesthetist, known as a CRNA), provides anesthesia.
Indications for anesthesia are diverse for different procedures and anesthesia types.
Types of anesthesia
There are 3 main anesthesia types:
- General anesthesia: this type of anesthesia makes you unconscious. You can’t see, feel, or hear anything. Plastic breathing tubes may be inserted into your mouth to protect your airways from secretions (gastric, mouth), to make you breathe by specialized breathing machine, and to deliver inhalational anesthetics to your lungs. The breathing tube is removed after the surgical procedure, before your awareness.
- Regional anesthesia: This type of anesthesia blocks pain in certain areas of your body. When peripheral nerve blocks are used, the doctor puts anesthetic drugs around the nerves that supply the body part that should undergo the surgical procedure. For example, it can be a leg or an arm.
Other types of regional anesthesia are spinal and epidural anesthesias. These block pain in the lower half of your body. For spinal anesthesia, an anesthesiologist makes an injection in your lower back and puts an anesthetic solution around your spine. Indications for spinal anesthesia are surgeries on your legs or lower part of the belly.
During epidural anesthesia, an anesthesiologist inserts a thin metallic tube (catheter) in your lower back around the spinal nerves. Then, an anesthetic solution is injected by this catheter in a repeated manner or continuously. Indications for epidural anesthesia are surgical procedures and pain control after surgeries.
Regional anesthesia can be used alone or in combination with general anesthesia or sedation. Sedation is a state of sleepiness and relaxation induced by sedating drugs. In contrast with general anesthesia, your sleep is not deep enough for painful surgical procedures, and during sedation doctors can wake you up immediately. Sedation is indicated for small, painful procedures (e.g., chest tube placement) or for diagnostic procedures (e.g., MRI).
- Local anesthesia: this type of anesthesia numbs only a small part of your skin or other tissues. It can be given as a cream, gel, or spray or injected by a needle.
Before the procedure
An anesthesiologist or an anesthetist does a preanesthetic evaluation, which means a physical exam and questions about:
- your health problems
- loose or false teeth
- all medicines that you take, including prescription and over-the-counter ones and supplements
- your habits (smoking, alcohol use, drug abuse)
- food and medicine allergies
- your past anesthesia experience
- your relatives that have anesthesia problems
The anesthesiologist also gives you instructions about fasting before the procedure and about which medications to take or avoid if you take any drugs.
During preoperative preparation, some lab tests, an electrocardiogram (ECG), or a chest X-ray may also be ordered.
After your preanesthetic evaluation, the anesthesiologist makes a decision about which type of anesthesia is best for you.
Preparation for anesthesia
For anesthesia preparation, you should:
- Keep fasting instructions.
- Follow the instructions that your healthcare provider gives to you about which medications to take or quit before your anesthesia.
- Stop smoking for at least 24 hours before anesthesia. For better prevention of respiratory complications, you should avoid smoking two weeks prior to anesthesia.
During the procedure
During the anesthesia, an anesthesiologist constantly monitors your vital signs: pulse, blood pressure, blood oxygen level, and respiration. During general anesthesia, the doctor also constantly adjusts anesthetic drugs to keep you asleep. An anesthesiologist also identifies and manages complications, like allergic reactions, etc.
Postanesthesia period and recovery
After local anesthesia, you can return to your normal activities if there are no contraindications. In contrast, after regional and general anesthesia, there are some limitations, as anesthetics stay in your organism for up to 24 to 48 hours. You should avoid driving or making important or legal decisions and should rest and recover.
Potential side effects
Most anesthesia side effects are minor and temporary. Some are predictable, and others are not. Here is the list of common side effects:
- nausea and vomiting
- back pain
- chills
- headache
- fatigue
- sore throat
- damage to your teeth
Complications
Though anesthesia safety has grown dramatically during the last decades, there is still a small percent of severe anesthesia complications. Rare but severe complications of general anesthesia include the following:
- anaphylaxis
- aspiration
- infection
- breathing problems
- injuries to arteries, veins, nerves, voice, or skin
- injuries to vital organs
- postoperative delirium
- anesthetic awareness
- malignant hyperthermia
- cardiac arrest
- death
Sources:
UpToDate
Mayo Clinic
Clevland Clinic
