Preparing for general anaesthesia is a critical process that ensures your safety during surgery. Your anaesthetist is responsible for your well-being throughout the procedure, and their ability to do so depends heavily on the information you provide and the instructions you follow. Failure to comply with these guidelines can lead to serious, life-threatening complications, potentially resulting in the delay or cancellation of your surgery. This guide addresses the most common things to avoid in the hours and days leading up to your anaesthetic.
Fasting: The Critical Rule
One of the most important pre-operative rules is to avoid eating or drinking. When you are under general anaesthesia, your body's protective reflexes, such as coughing and swallowing, are suppressed. Aspiration occurs when stomach contents enter the lungs, and an empty stomach is the best defense against this dangerous and potentially fatal complication.
Food and Liquids
The standard instruction is to have no solid food for a minimum of six to eight hours before surgery. For clear liquids, modern guidelines from the American Society of Anesthesiologists (ASA) often permit consumption up to two hours prior for healthy patients, though many facilities still follow a stricter timeline. Clear liquids include water, apple juice, black coffee, or tea without milk or cream. Individual circumstances and the time of the procedure will dictate the exact fasting schedule provided by your care team.
Special Dietary Considerations
For patients with diabetes or those taking certain medications like GLP-1 agonists (e.g., Ozempic, Wegovy), special instructions are necessary. These medications can slow gastric emptying, meaning the stomach may not be empty even after the standard fasting period, increasing aspiration risk. It is crucial to discuss these with your anaesthetist well in advance.
Medication Management Before Anaesthesia
Certain medications, both prescription and over-the-counter, can have dangerous interactions with anaesthetic agents or increase the risk of complications like bleeding. Your care team must have a complete and accurate list of everything you are taking.
Medications to Discontinue
- Blood Thinners and NSAIDs: Drugs such as aspirin, warfarin (Coumadin), clopidogrel (Plavix), ibuprofen (Advil, Motrin), and naproxen (Aleve) interfere with blood clotting and must be stopped one to two weeks before surgery, depending on the specific medication.
- Herbal Supplements and Vitamins: Many popular supplements, including ginseng, ginkgo biloba, St. John's Wort, vitamin E, and fish oils, can increase bleeding risk or interact with anaesthesia. These should typically be stopped one to two weeks before surgery.
- Diabetes Medications: As mentioned, GLP-1 agonists and other diabetes medications must be discussed with your physician. They may need to be held for a specific period before surgery to prevent complications.
Medications to Continue
It is important to note that not all medications should be stopped. Some, like certain blood pressure medications (e.g., beta-blockers), may need to be taken with a small sip of water on the day of surgery. Your anaesthetist will provide precise instructions regarding which medications to continue and which to hold.
Substances to Avoid
Beyond prescribed and over-the-counter medications, other substances can profoundly impact your body's reaction to anaesthesia.
Alcohol
Consuming alcohol in the 24 to 48 hours before surgery is strongly discouraged. Alcohol can thin your blood, interfere with anaesthetic drugs, and increase dehydration. For chronic drinkers, withdrawal symptoms during or after surgery pose a significant risk, and a higher dose of anaesthesia may be required to achieve the desired effect.
Smoking and Nicotine
Ideally, you should stop smoking several weeks before surgery, but stopping at least 24 hours beforehand offers immediate benefits. Smoking compromises heart and lung function, increases the risk of blood clots, and impairs wound healing, making post-operative recovery more difficult.
Recreational Drugs
Use of recreational drugs must be disclosed to your anaesthetist. Stimulants like cocaine and methamphetamine can cause cardiac instability during surgery. Cannabinoids, including marijuana, can increase the need for anaesthetic and heighten pain perception after surgery. The effects of recreational drugs, combined with anaesthesia, can be toxic and potentially fatal.
Other Pre-Surgical Precautions
Your care team will provide a detailed checklist of things to avoid on the day of your surgery. These often include:
- Makeup and Nail Polish: Remove all makeup, nail polish (especially from fingers), and lotions. These can interfere with monitoring devices that measure blood oxygen levels.
- Jewelry and Piercings: Remove all jewelry and piercings to prevent infection and avoid potential burns from medical equipment like electrosurgical units.
- Dental Appliances: Notify the anaesthetist of any loose teeth, dentures, or bridges, as these can pose a risk during intubation.
Comparing Safe vs. Prohibited Actions Before Anaesthesia
| Activity | Prohibited (Most Cases) | Allowed (with Doctor's Approval) |
|---|---|---|
| Eating/Drinking | Solid food, dairy products, non-clear liquids, alcohol within 6-8+ hours | Clear liquids up to 2 hours before arrival |
| Medications | Blood thinners (NSAIDs, aspirin, Plavix, Xarelto), many diabetes and weight-loss drugs | Certain heart and blood pressure medications with a small sip of water |
| Supplements | Ginseng, ginkgo, St. John's Wort, vitamin E, fish oil within 1-2 weeks | Generally none unless explicitly approved by your anaesthetist |
| Lifestyle | Smoking, vaping, alcohol consumption within 24+ hours | None |
| Personal Items | Makeup, nail polish, jewelry, body piercings | None |
Conclusion: The Importance of Communication and Compliance
Your personal health history, daily habits, and medication list are crucial pieces of information for your anaesthesia team. By following the prescribed instructions on what not to do before a general anaesthetic, particularly regarding medications and substances, you play an active and vital role in minimizing risks and ensuring a safe surgical experience. Always be completely transparent and do not hesitate to ask questions. Remember, these rules are in place for your safety.
For additional guidance and patient resources, consult authoritative sources like the American Society of Anesthesiologists (ASA).
