The 5 Most Common Complications From General Anesthesia

Many people are afraid of getting general anesthesia. Yet the most feared complications are actually quite rare. For a healthy person, the chance of dying from anesthesia is 0.0004%. The chance of being left paralyzed from a spinal or epidural anesthetic is 0.005%. The chance of being aware while under anesthesia is 0.13%. 

Though anesthesia is safer now that it’s ever been, that doesn’t mean there aren’t potential risks. The most common complications from anesthesia are usually unpleasant but not dangerous. And even so, your anesthesiologist is medically trained to prevent these complications and treat them if they do develop.

If you’re having surgery or a procedure, here’s what you need to know about the most common complications of general anesthesia.

Postoperative nausea and vomiting (PONV)

Postoperative nausea and vomiting (PONV) is one of the most common complications of all types of anesthesia. But it’s especially common after general anesthesia. 

PONV can be serious enough to keep you in the hospital longer after your surgery. It usually begins during the first few hours after your procedure. The chance of getting PONV is about 10%, but the risk goes up if you have a history of prior PONV, motion sickness, or you receive opioid medications before or during your procedure. 

To prevent you from getting PONV, your provider may give you medication to prevent nausea and vomiting. Examples of these medications include:

• Ondansetron 

• Chlorpromazine

• Casopitant and rolapitant 

• Dexamethasone

• Promethazine 

• Scopolamine

Studies show that receiving one of these medications before surgery can decrease your risk of developing PONV by 25%.

Sore throat

When you receive general anesthesia, your anesthesia team will often insert a breathing tube into your windpipe (trachea) to help you breathe during surgery. This can cause a sore throat afterward. If placing the breathing tube was difficult, you might also sustain a cut in your throat, or even a chipped tooth.

A sore throat occurs roughly 30% of the time with general anesthesia. People who have longer operations or a history of a lung condition are more likely to develop a sore throat after anesthesia.

Your sore throat can be treated with different medicines, including:

• Steroids

• Licorice gargle

• Azulene sulfate gargle

• Topical lidocaine

• Topical ketamine

• Nonsteroidal anti-inflammatory drugs (NSAIDs)

A sore throat usually goes away within a few days — though, for some people, it can fade much quicker.

Muscle aches

People commonly experience muscle aches and backaches after anesthesia.

In the case of muscle aches, a common cause is a medicine called succinylcholine, which relaxes your muscles and paralyzes you for a few minutes while under anesthesia. This allows your provider to place a breathing tube in your windpipe. Succinylcholine may cause you to experience muscle stiffness and aches for several days after your operation. 

People are more likely to develop post-anesthesia muscle aches if they are: 

• Female

• Between 15 and 50 years old

• More sedentary (less-active lifestyle)

• Having minor (as opposed to major) surgery

Anesthesia teams are very aware of this potential problem. If you are at higher risk for developing this complication, they will try to use an alternative muscle relaxant when possible. 

People also sometimes complain of a backache after anesthesia. The chance of a backache increases if your surgery lasts longer than 40 minutes. Backaches happen because you’re lying still on a hard operating table for a long time, and this overstretches the ligaments in your back.  Normally, you would move around to relieve the stretching. But you can’t move while you’re under anesthesia, and so the ligaments remain stretched and become sore. 

To help prevent this, the operating team may place an inflatable lumbar support under your back, or a pillow under your knees, to lessen the strain on your back and lower your risk of backache. If you develop a backache after surgery, it usually disappears after a few days. Your healthcare team may also give you a heat pack and NSAIDs to help with the discomfort after surgery. It can also be helpful to work with a physical therapist during your recovery.

Nerve injuries

You can suffer a nerve injury while under anesthesia, but this is very rare and is reported in less than 1% of anesthesia cases.

Nerve injuries can happen in several ways: 

• Direct nerve damage: Sometimes you need a local anesthetic or other injection during your surgery in addition to general anesthesia. If the needle used for the injection hits the nerve, it can cause damage. To avoid this, providers will use ultrasound imaging to guide needle placement. 

• Poor blood flow: Certain conditions, like diabetes, high blood pressure, and smoking, cause poor blood flow. When people with these conditions develop low blood pressure or low oxygen levels during surgery, their blood flow worsens. This causes less oxygen to get to the nerves, and they can become injured.

• Compression and stretching: People asleep under general anesthesia are usually placed in a safe and comfortable position to shield their nerves from injury. But sometimes a person’s arm or leg might accidentally press against something, or become overextended during the operation without the operating team knowing. The person then wakes up with nerve damage, called “neuropraxia.” This occurs more commonly in nerves in the arms than in the legs. The nerve most often compressed during surgery is the ulnar nerve, which some people call the “funny bone,” and is most vulnerable at the elbow. People with neuropraxia wake up with numbness, pain, tingling, or weakness in the affected area. 

Compression and stretching injuries are the most common form of nerve injuries while under anesthesia. People usually recover within days or weeks, although sometimes it can take a few months for symptoms to go away completely. 

Allergic reactions

Anesthesia medications can cause allergic reactions. The chance of an allergic reaction from anesthesia is less than 0.5%. Symptoms can be mild, such as a skin rash, or severe, like anaphylaxis.

Before surgery, your provider will ask you if you have any history of allergies to medications, chemicals, or materials. Make sure to let your team know if you have a latex allergy or a preservative allergy, such as methylparaben or metabisulfite, which are in some anesthesia medications.

If you have a history of multiple allergies, your team may give you steroids and antihistamines before surgery to lower your chance of an allergic reaction. If you have a reaction anyway, your team can treat it with more steroids, antihistamines, and epinephrine.

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Written by:

Ronald W. Dworkin, MD, PhD

Ronald W. Dworkin, MD, is a board-certified anesthesiologist who has been practicing anesthesiology in a community hospital for 30 years. He has taught in the honors program at George Washington University for over 10 years and works as a senior fellow at the Hudson Institute.

Edited by:

Patricia Pinto-Garcia, MD, MPH

Patricia Pinto-Garcia, MD, MPH, is a medical editor at GoodRx. She is a licensed, board-certified pediatrician with more than a decade of experience in academic medicine.

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