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What Does Being Anesthetized Do to Your Body?

A person being anesthetized for surgery.

If you are going to have a medical procedure or surgery, your doctor or certified registered nurse anesthetist will talk to you about the type of surgical anesthesia they will use to manage pain and keep you comfortable. Anesthesia is very safe, but like all medications, anesthesia drugs can cause side effects and complications. Please continue reading to understand what anesthesia medications do to your body and some of the side effects of anesthesia.

What are the different types of anesthesia used in medical procedures?

Local Anesthesia

Local anesthesia numbs a small part of the body. It is used to perform minor procedures such as a skin biopsy, mole removal, or closure of a deep skin wound with stitches

The local anesthetic medicine is injected locally at the surgical site. You remain awake throughout and may feel some pressure or tugging, but no pain. Local anesthesia allows many common procedures to be performed safely and painlessly with minimal preparation, a short recovery time, and a relatively lower cost. 

Side effects of local anesthesia are rare and usually minimal, such as mild soreness at the injection site. Rarely, there can be an allergic reaction to the local anesthetic.

IV/Monitored Sedation

Doctors sometimes use sedation (medications to help you relax) along with anesthetic medicines (local or regional anesthesia). This is also called conscious sedation or monitored anesthesia care. It is typically used for minor procedures and surgeries for which local anesthesia alone is insufficient, but general anesthesia is not required. Examples include certain biopsies, endoscopies, and colonoscopies

The medications are given through an intravenous (IV) line. The anesthesia stages (level of sedation) can vary from minimal (you will be drowsy but will be able to understand your doctor and answer questions) to moderate (you might fall asleep and remember nothing or only parts of the procedure) to deep (you’ll be in a deep sleep and with no recollection of the procedure, but you won’t be completely unconscious like with general anesthesia). Deep sedation can affect your breathing, and you may need oxygen.

Most people recover quickly from sedation. Possible side effects of monitored sedation include drowsiness, headache, and nausea

Regional Anesthesia

Regional anesthesia includes spinal blocks and epidurals. It is used for pain management in a large area of the body, such as an arm, leg, abdomen, or from the waist down. The medications are given by injection or a small tube called a catheter. 

Regional blocks are used when local anesthesia is insufficient, but the patient must remain awake. For example, epidurals are commonly used during labor and delivery so that the mother can remain awake and push but does not feel pain. A spinal block is stronger and is used during surgeries such as cesarean sections (C-sections) to stop you from feeling pain. The use of regional anesthesia during childbirth provides pain control for the mother while protecting the baby from exposure to anesthesia medicines. 

Side effects of regional anesthetic drugs include headache, backache, and urinary retention (difficulty urinating). Possible complications associated with spinal anesthesia include nerve injuries, catheter infections, spinal or epidural hematoma, epidural abscess, meningitis, drug toxicity, and cardiac arrest (rare). 

General Anesthesia

General anesthesia is used during major surgeries like heart surgeries, joint replacements, and cancer surgeries. While it is associated with more serious complications, general anesthesia makes many life-saving surgeries possible. When a surgical procedure is done under general anesthesia, it is performed in an operating room by a combined surgical and anesthesia team. 

The anesthesia care team is led by a specially trained doctor called an anesthesiologist. The team gives the general anesthetic medications through a mask or IV line. These anesthetic drugs make you completely unconscious and slow down many of your body’s functions. Because of these effects of anesthesia, you may need a breathing tube to help you breathe. The anesthesia team carefully monitors your vital signs (heart rate, blood pressure, breathing rate, and oxygen levels) throughout the duration of the procedure. Once the surgery is over, the general anesthesia is reversed and you regain consciousness (slowly wake up) in the recovery room.

Side effects of general anesthesia include nausea, vomiting, shivering (feeling cold), dizziness, dry mouth, hoarseness, sore throat, blurred vision, itching, irregular breathing (especially after chest or abdomen surgery), muscle aches, and difficulty passing urine. You may need pain medication for pain control after a major surgery once the general anesthesia wears off. 

Very rarely, there can be a serious allergic reaction (anaphylaxis) to the drugs used in general anesthesia. Another rare occurrence is experiencing unintended intraoperative awareness, or anesthesia awareness, where there is an accidental awareness of surroundings while under general anesthesia. While there is no pain, anesthesia awareness can be distressing and lead to post-traumatic stress disorder. Other potential complications include:

  • Malignant hyperthermia (a reaction to anesthetic drugs that causes a dangerous rise in body temperature, muscle spasms, and rigidity).
  • Postoperative cognitive dysfunction (newly diagnosed memory problems and intellectual difficulties after surgery).
  • Postoperative delirium (sudden fluctuations in mental status).

How long does anesthesia stay in your body?

How long anesthesia stays in your body depends on the type of anesthesia used. Local anesthetic usually wears off in a few hours. After sedation is removed, you wake up in about 20 minutes, but sedative effects can take up to 6 hours to wear off. Depending on the anesthesia medicines used, regional nerve blocks can last for 3-6 hours or longer. It can take up to 24 hours for general anesthesia drugs to completely leave your system, during which time you may feel groggy, and your reflexes and judgment may be affected.

How does anesthesia affect the body long-term?

Anesthesia is reversible and does not usually cause any long-term effects. Some studies have shown that very young and very old people may be vulnerable to long-term effects from general anesthesia. However, it is difficult to say whether these changes occur from the disease process, the surgery, or the anesthesia. 

Does anesthesia damage your body?

Anesthesia is very safe and does not usually damage the body. However, some people are at higher risk of anesthesia complications. That’s why it’s important to give your medical doctor, surgeon, and anesthesia team a complete medical history. Significant health conditions, for example, high blood pressure, lung disease, or sleep apnea, are risk factors for anesthesia complications. Similarly, certain medications, such as muscle relaxants or even herbal supplements, can increase the risk of anesthesia causing harm. You should give your healthcare team a complete list of your medications to prevent dangerous drug interactions.



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