What Is Anesthesia?

Anesthesia is a very common and safe medical procedure that prevents you from feeling pain during medical interventions, such as surgery, certain diagnostic tests, and dental work.

It works by preventing your nerves from passing signals to the brain, causing numbness in a specific area of the body — from a small area to a whole region of your body — or inducing a controlled state of unconsciousness. 

There are several types of anesthesia, which are used for different purposes and have different effects on the body.

Local Anesthesia

Unlike other forms of anesthesia, local anesthesia can be performed by any medical professional and does not require specialized training. It’s commonly used for minor procedures, such as to block pain from a tooth during dental work or an area of skin that requires stitches.

Regional Anesthesia

Administered by an anesthetist, regional anesthesia blocks pain in a larger region of the body, such as an arm, leg, or the entire lower half of the body. It targets larger nerves that transmit signals across an entire area of the body.

Hand surgery, for example, requires regional anesthesia, given as a shot of numbing agent near the nerves in the armpit, causing your whole arm to go numb. Epidurals during childbirth are another common example.

Monitored Sedation

• Minimal sedation relaxes you while leaving you awake and able to respond to questions or instructions.

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• Moderate sedation will make you sleepy, but you can be awakened easily and interact with your healthcare team, though you may not remember any of it.

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• Deep sedation will give you a nice nap (you won’t be completely unconscious but you won’t be able to remember it, either); while you can breathe on your own, you will need close monitoring and may need to be given oxygen because the medications can cause your breathing to become slower or shallower.

General Anesthesia

Used for major, invasive surgeries — such as those that are time-consuming like back surgery or involve internal organs — general anesthesia is likely what you imagine when you hear the word “anesthesia.” It affects your entire body, making you unconscious and preventing you from feeling pain or even moving. 

Anesthesia allows healthcare providers to perform surgeries and other treatments safely and efficiently while keeping you comfortable and free from distress. It’s used to eliminate pain and discomfort during a wide range of medical procedures, including:

• Stitches
• Dental procedures including tooth removal and root canals
• Eye surgery

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• Biopsies (removal of tissue for examination under a microscope)

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• Epidural during labor
• C-section
• Joint replacement
• Various non-organ surgeries including wrist, shoulder, knee, and ankle surgeries
• Major surgeries that involve the heart, abdominal organs, back, or brain
• Endoscopy and colonoscopy
• Gynecological procedures
• Cardiac catheterization, the insertion of a catheter into the heart
• Organ transplants

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Depending on your procedure and preferences, your healthcare provider will administer a local anesthetic via:

• Topical lotion or spray
• Skin patch

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• Eye drop
• Oral rinse

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• Injection with a needle and syringe

Anesthesia specialists administer regional anesthesia by injection, with the location depending on what area of the body requires numbing.

They administer sedation and general anesthesia intravenously or as an inhaled gas (through a mask covering the mouth and nose).

Local anesthesia doesn’t require any special preparation. For other types of anesthesia, your healthcare provider or anesthesiologist will provide specific instructions.

• Your allergies, particularly any allergic reactions you have had to anesthesia (including local) in the past
• Herbal supplements you take, which may affect your heart rate and blood pressure
• Your medications, including birth control or erectile dysfunction drugs like sildenafil (Viagra)
• Your smoking and drinking (alcohol) habits
• If you are breastfeeding, pregnant, or might be pregnant

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• Your use of street drugs, including marijuana, cocaine, amphetamines, or others (keep in mind this is private information between you and your providers)

Some general guidelines to follow before your procedure include:

• Stop smoking one week before your procedure.

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• Stop taking herbal supplements one to two weeks before.

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• Stop taking certain medications, as instructed.
• Stop eating solid foods and drinking liquids as directed, typically eight hours and two hours before arrival at the medical facility, respectively.
• Stop using cannabis at least two hours before your procedure and possibly longer, as advised by your anesthesiologist.

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• Arrange for someone to bring you home after your procedure, as you won’t be allowed to drive yourself home or use a taxi or ride share service if you’ve had any kind of sedation.

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• Wear loose, comfortable clothing.

During anesthesia, your anesthesia care provider will closely monitor your vital signs, watching for any changes in your body functions, such as:

• Heart rate and rhythm
• Blood pressure
• Body temperature
• Oxygen levels
• Breathing

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They will also manage any fluid and blood replacement you may need and may monitor brain activity for some procedures.

With local or regional anesthesia, you will be awake but free of pain (you may still feel pressure during your procedure). If you are sedated, you’ll feel relaxed and drowsy and may fall asleep.

• Allergic reactions to anesthetic drugs
• Anesthesia awareness
• Malignant hypothermia, a reaction to anesthesia that causes a quick fever and muscle contractions
• Breathing difficulties, especially if you have obstructive sleep apnea

Anesthesia is riskier for you if you have or have had:

• Diabetes
• Heart disease
• High blood pressure
• Kidney problems
• Lung conditions
• Obesity
• Sleep apnea
• Stroke
• Seizures
• A history of smoking or drinking two or more alcoholic beverages a day

Recovery time varies depending on the type of anesthesia used.

With general anesthesia, you will likely recover within a few hours, but you may experience pain as the anesthesia wears off, depending on the type of procedure you had. You may also continue to be sleepy and have impaired judgement and reflexes during recovery — it’s best to have someone with you for at least the first 24 hours after general anesthesia.

Recovery from sedation is similar to general anesthesia, but the effects wear off quicker.

• Nausea and vomiting
• Sore throat
• Confusion, particularly with older patients
• Muscle aches
• Itching
• Chills and shivering

In rare cases, general anesthesia can cause a serious complication called postoperative cognitive dysfunction — long-term memory and learning problems. You are more at risk of this complication if you:

• Are older in age
• Have heart disease, Parkinson’s disease, or Alzheimer’s disease
• Previously had a stroke

Side effects from sedation include:

• Headache, which may occur a few days after the procedure
• Nausea
• Drowsiness
• Minor back pain
• Difficulty urinating
• Hematoma, or bleeding beneath the skin at the injection site

Sedation can also cause serious but rare complications including nerve damage and pneumothorax, or lung collapse (if anesthesia was injected near the lungs and the needle accidentally punctured the organ).

Rarely, regional anesthesia can cause headache, backache, and low blood pressure and heart rate. Local anesthetic toxicity (when you receive too much injected anesthesia) is a rare complication for both local and regional anesthesia — it causes confusion, slowed heartbeat, trouble breathing, and seizures.

• Anesthesia is a vital part of modern medicine that allows for pain-free and safe medical interventions.
• While it comes with some risks and side effects, especially with general anesthesia, it is considered a very safe procedure.
• By understanding what to expect and following guidelines provided to you, you can approach your procedure with confidence and peace of mind.