Anesthesia safety and risks

How can I reduce my risk?
Several lifestyle factors, including smoking, obesity, and cannabis or recreational drug use can increase the risk of an adverse reaction to anesthesia. Your anesthesiologist will advise you on what you can do before surgery to lower your risk of complications.

During your pre-operative assessment, it’s important to provide as much detail as you can about your health and habits. For example, be sure to tell your anesthesiologist if you suspect you have sleep apnea—even if you haven’t been formally diagnosed—as this condition can impact how you respond to anesthesia. If you’re not sure how to answer a question during your assessment, ask for clarification.

To reduce your risk of complications and speed up the healing process, you can also familiarize yourself with the following pre-surgery wellness tips:



Common anesthesia questions and myths.

1. What if I wake up in the middle of surgery? Although anesthesia awareness has been popularized in film and TV, it happens very rarely—to an estimated 1 out of 15,000 patients outside of high-risk groups. Your anesthesiologist will be highly trained to watch for this situation and quickly return you to a state of unconsciousness if it does occur.
2. Does anesthesia cause brain damage? There’s little to no scientific evidence that anesthesia itself causes this. When it’s observed postoperatively, brain damage is typically a result of an underlying condition or a complication. For example, not getting enough oxygen during the operation can lead to brain damage. However, this would typically be because of a pre-existing medical condition, complications during surgery, or cardiac arrest. It is not a direct effect of the anesthetic drugs.
3. What if I’m allergic to the anesthetic? Many patients mistake common side effects of anesthesia for an allergic reaction. However, a true drug allergy usually produces different reactions, including hives, difficulty breathing, and swelling. Having an allergic reaction to an anesthetic drug is highly unlikely in Canada, but if it does happen, your anesthesiologist is trained to handle the situation. You would also undergo allergy testing after surgery so that the drug you’re allergic to can be documented and avoided in the future.
4. What are the risks of anesthesia? In every procedure, the risks and potential side effects of anesthesia depend on many different factors for each patient. Click here to read about possible risks and how to reduce your likelihood of complications. 
5. Is my child more at risk? In general, the risk to a healthy child is roughly the same as it is to a healthy adult. Like adults, children who are significantly ill and need a major operation are at a higher risk overall. However, children typically aren’t susceptible to many risk factors that impact adults, such as high blood pressure or heart problems. Children under a year old may be at greater risk of complications, due to their airways and breathing being more difficult to control. A pediatric anesthesiologist is best equipped to provide specialized pediatric anesthesia care—particularly for those who are very young or have a serious medical condition.
6. During labour, can an epidural harm me or my baby? The amount of epidural medication that may reach your baby is very minimal, and there’s no scientific evidence that it will harm them. Common side effects of an epidural during and after giving birth include small areas where pain isn’t fully blocked, weakness or heaviness in the legs, a temporary backache, low blood pressure, nausea, or difficulty passing urine. All of these side effects improve within a few hours. Very rare complications include nerve damage, infection, or blood clots. In Canada, epidurals are considered very safe and are generally performed without complications.
7. My family member died under anesthesia. Am I at risk? Some genetic conditions can lead to complications from anesthesia—and most can be safely managed by your anesthesiologist. Keep in mind that several factors, such as your relative’s age and overall health, as well as the level of anesthesia care available when they had their operation, may have played a role in the outcome of the procedure. If your relative’s death was recent, unexpected, and unexplained, your anesthesiologist will ask for details about their operation and may refer you for testing to determine how best to get you through surgery safely.
8. Can I talk to my anesthesiologist before surgery? Yes! Several weeks before your surgery, you will have a consultation with your anesthesiologist or a member of your anesthesia care team, and have the opportunity to ask any questions. On the day of your surgery, your anesthesiologist will check in with you before you go into the OR. Visit the Getting Ready for Surgery page to learn more. 
9. How likely am I to die? In Canada, your risk of dying as result of anesthesia is very small—roughly between 1 in 200,000–400,000 for a healthy person. This is largely due to anesthesiologists’ ability to continuously monitor your condition and quickly and effectively intervene when needed. If you have any concerns despite this very low risk, be sure to share them with your anesthesiologist. They will be able to reassure you in most instances.