What are the Side Effects of Anesthesia?

Anesthesia is a critical part of modern medicine, allowing patients to safely undergo major surgeries and procedures. However, like any medical intervention, it can cause side effects or complications.

These depend on the type of surgery, the patient’s age, health, and medical history. Knowing what to expect can help patients and anesthesia providers prepare and manage these adverse effects.

General Anesthesia Side Effects & Complications.

General anesthesia puts patients into a deep sleep so they don’t feel pain during surgery. While generally safe, it can lead to temporary side effects or, more rarely, serious complications.

A side effect is a mild, expected, and usually temporary result of anesthesia. A complication is more serious, can last longer, and may require extra treatment.

Common Side Effects.

• Drowsiness or Fatigue: Very common after anesthesia; can last for several hours.
• Dry Mouth: Caused by drugs that reduce saliva production.
• Sore Throat or Hoarseness: Common if a breathing tube is used. The throat may feel scratchy, or the voice may sound different.
• Nausea and Vomiting (PONV): Affects about 1 in 3 patients. It usually resolves within a few hours and can be treated with medication.
• Itching: Often caused by opioid medications used during or after surgery.
• Shivering or Chills (Hypothermia): A common response as the body rewarms after surgery.
• Dizziness: Often caused by low blood pressure, especially when standing up.
• Confusion or Memory Problems (Temporary): Patients may feel foggy or have trouble remembering. This usually lasts a few hours to a couple days. It is more common in older adults.
• Muscle Aches: Caused by muscle relaxants or the way the body was positioned during surgery.
• Headache: May be due to dehydration, stress, or the anesthesia itself.
• Difficulty Urinating: Temporary and more likely after certain surgeries or when opioids are used.
• Emergence Delirium: Some people, especially children, may wake up confused, upset, or acting strangely. This usually resolves quickly with calm support.

Common Neurocognitive Complications.

• Postoperative Delirium: A state of confusion, disorientation, and agitation that can happen in the first few days after surgery and may last up to a week. It’s common in older adults and those with memory problems.
• Postoperative Cognitive Dysfunction: Problems with memory, focus, or clear thinking that can last weeks or months after surgery. It’s more common in older patients and after major surgery.

Rare Complications.

• Respiratory Problems: Includes trouble breathing or lung infections like pneumonia.
• Allergic Reactions: Can range from a mild rash to a severe, life-threatening reaction called anaphylaxis.
• Malignant Hyperthermia: A dangerous reaction to certain anesthesia drugs, causing high fever, muscle stiffness, and other serious issues. It needs immediate treatment.
• Nerve Damage: can occur if a patient is positioned incorrectly during surgery.
• Anesthesia Awareness: patients may regain some awareness during surgery, often due to insufficient anesthesia.
• Death: Extremely rare and usually related to pre-existing health conditions or complications during surgery.

When to Seek Medical Attention.

Most adverse effects of anesthesia are mild and go away on their own. However, patients should contact their healthcare provider if they experience:

• Severe or ongoing nausea and vomiting.
• Trouble breathing or chest pain.
• Signs of infection, such as fever, redness, or swelling at the surgical site.
• Severe headaches or confusion that don’t improve.
• Numbness, weakness, or other unusual symptoms that last longer than expected.

How to Reduce the Risk of Side Effects & Complications.

To lower your risk, patients should:

1. Discuss Their Medical History: Tell your anesthesia provider about any health conditions, allergies, or medications you’re taking.
2. Follow Pre-Surgery Instructions: This may include fasting or adjusting medications before surgery. Always ask your anesthesia provider before starting or stopping any medications.
3. Avoid alcohol, Smoking, and Recreational Drugs: These can interfere with anesthesia, slow healing, and increase complications. Patients should disclose recent use—even if it’s uncomfortable—so their team can adjust your care safely.
4. Ask Questions: Understand the type of anesthesia being used and its potential side effects.
5. Follow Post-op Instructions: Take prescriptions as directed, stay hydrated, and resume activity as approved by their healthcare team.
6. Report Side Effects: Contact their provider if they experience unusual or concerning symptoms after surgery. Treating symptoms early may help prevent more serious complications.