Quick Answers
The recommended fasting times before anesthesia are:
- 8 hours for food (solids)
- 6 hours for breast milk
- 4 hours for infant formula
- 2 hours for clear liquids
These fasting times are guidelines to ensure your stomach is empty before anesthesia, which helps prevent aspiration. However, fasting times may be adjusted based on your age, medical conditions, procedure type, and other factors. Your anesthesia provider will give you specific instructions on fasting times before your procedure.
Why Fasting is Important Before Anesthesia
Fasting before anesthesia allows your stomach to empty and reduces your risk of regurgitation and aspiration during anesthesia.
Aspiration is when stomach contents enter the lungs, which can cause aspiration pneumonia. This is a serious risk because anesthesia relaxes the muscles in your airway that normally prevent vomit from entering your lungs.
By fasting before anesthesia, your stomach has less volume and acidity, lowering aspiration risk. Fasting ensures:
- Your stomach is less full so there is less to regurgitate
- Gastric fluids are less acidic, reducing damage if aspiration occurs
- No food is present to obstruct your airway if regurgitation occurs
Fasting is especially important if you have gastroesophageal reflux disease (GERD), hiatal hernia, delayed gastric emptying, or are obese – all risk factors for aspiration.
Clear Liquid Fasting Guidelines
What are Clear Liquids?
Clear liquids are liquids you can see through. They leave little residue in your stomach during digestion.
Examples of clear liquids include:
- Water
- Black coffee or tea (no milk or cream)
- Clear broth or bouillon
- Clear juice like apple juice (no pulp)
- Plain gelatin
- Popsicles without fruit or cream
- Soda
- Clear nutritional supplements
Avoid milk, juices with pulp, alcoholic beverages, and other liquids you cannot see through.
How Long to Fast from Clear Liquids
You should fast from clear liquids for 2 hours before anesthesia.
This short 2 hour fasting period is considered safe because:
- Clear liquids empty from the stomach rapidly – within 30 to 90 minutes
- They leave little residue that could cause aspiration issues
You may be instructed to drink clear liquids up until 2 hours before your scheduled anesthesia time. Avoid prolonged fasting from clear liquids, which can lead to dehydration, headaches, dizziness, and low blood pressure.
Exceptions
Some situations where longer fasting from clear liquids may be required:
- Emergency surgeries – NPO guidelines are recommended
- Conditions causing delayed gastric emptying – Like gastric outlet obstruction, gastroparesis
- Obese patients – Delayed gastric emptying so require longer fasting
Discuss any conditions or special circumstances with your anesthesia provider.
Fasting Guidelines for Food and Milk
How Long to Fast from Food/Solids
You should fast from all food and solids for 8 hours before anesthesia. This includes:
- Solid foods
- Meals
- Snacks
- Hard candies
- Gum
An 8 hour fast from solids ensures your stomach content is minimized at the time of anesthesia. After 8 hours, little solid food remains in the stomach.
How Long to Fast from Breast Milk
For breastfeeding infants, fasting from breast milk may be shorter:
- Age 0-6 months: 4 hours
- Age 6-12 months: 6 hours
Breast milk empties faster than formula or solids. A shorter fast is thought to be safe for breastfed babies.
For breastfeeding mothers, follow the 8 hour fasting guidelines for solids and light meal guidelines before anesthesia.
How Long to Fast from Formula
For infants taking formula, fast for:
- Age 0-6 months: 6 hours
- Age 6-12 months: 6-8 hours
Formula stays in the infant stomach longer than breast milk so requires a longer fast.
Fasting Exceptions
Some situations where solid food fasting requirements may differ:
- Emergency surgeries – NPO guidelines recommended
- Patients with reflux, delayed emptying – Longer fasts may be required
- Obese patients – Longer fasts due to delayed gastric emptying
- Infants and children – Shorter fasts may be allowed
Talk to your anesthesia provider about your specific needs and concerns.
Eating Before Anesthesia
While fasting is important, you don’t need to fast for extremely long times before anesthesia. Prolonged fasting can be unhealthy.
Here are some general guidelines on eating before anesthesia:
- Eat light meals up until 8-10 hours before your scheduled anesthesia time
- Drink clear liquids up until 2 hours before anesthesia
- Avoid heavy, fatty, or large meals before anesthesia – they take longer to digest
- Don’t overeat right before fasting, this will leave excess food in your stomach
- Stay well hydrated up until your fast with water and clear liquids
A light meal may include toast, cereal, yogurt, fruit, crackers, eggs, soup, juice. Avoid meat, fried foods, whole grains, dairy, fiber.
Special Instructions Based on Age
Infants Under 6 Months
– Breastfeed on demand up until 4 hours before anesthesia
– Formula can be given up to 6 hours before anesthesia
Older Children
– Encourage carbohydrates and discourage fatty foods before fasting
– Avoid dehydration by maintaining clear liquids until fasting time
Elderly Patients
– May need shorter pre-op fasting times due to malnutrition risk
– Anesthesia provider may allow light meal closer to surgery time
Diabetic Meal Guidelines
Patients with diabetes need special meal planning before anesthesia and surgery.
Diabetics should:
- Eat light meals before fasting
- Avoid carbohydrate loading
- Monitor blood glucose closely before and after surgery
- Adjust insulin dosage as needed
- Communicate with anesthesiologist about diabetes management
The goal is stable blood glucose levels during the perioperative period. Work closely with your healthcare team for optimal diabetic control around your procedure.
Drinking Before Anesthesia
Hydration is important before anesthesia, but avoid overhydrating right before your fast.
Here are some hydration guidelines:
- Drink clear fluids regularly in the days leading up to surgery
- Avoid alcohol for at least 24 hours pre-op
- Stop regular fluids 2 hours before anesthesia
- Sips of water may be allowed up to 1 hour pre-op for medications
- Avoid carbonated beverages – they expand the stomach
Your anesthesia team may provide specific fluid recommendations based on your health status.
If you are severely dehydrated before anesthesia, IV fluids may be given after you are under to rehydrate you.
Oral Hydration Solutions
Oral hydration solutions like Pedialyte can help optimize hydration status before surgery.
Benefits include:
- Rehydrate without overexpanding fluid volume
- Provide electrolytes
- Well tolerated up until 2 hour fasting time
Oral hydration solutions may be recommended if you are dehydrated before a scheduled procedure or have fluid losses from vomiting, diarrhea.
Chewing Gum and Mints Before Anesthesia
Can you chew gum or suck on mints before anesthesia?
The answer is no. Here’s why:
- Increases swallowed air which expands the stomach
- Stimulates gastrointestinal motility
- Pieces or particles could enter the airway during anesthesia
- Stimulates saliva production and increases gastric secretions
For these reasons, avoid gum, mints, hard candies within 8 hours of receiving anesthesia. They count as solid food.
Sips of water are allowed up to 1 hour pre-op if needed to swallow medications.
Common Fasting Questions
Why can I drink water up to 2 hours before but not eat solid foods?
Water and other clear liquids empty from the stomach quickly, usually within 30 to 90 minutes. Very little liquid remains after 2 hours. Solid foods require much longer to digest and empty from the stomach, up to 8 hours, so require longer pre-op fasting.
What if I accidentally eat or drink before anesthesia?
Inform your anesthesia care team if you eat or drink anything past the fasting deadline. Your surgery may need to be delayed or canceled depending on timing, contents ingested, and urgency of the procedure. Your team can determine the best course of action to prevent aspiration risk.
Why are fasting times longer for children having surgery?
Infants and toddlers are at higher risk of anesthesia complications, including aspiration. Their airways are smaller, making obstruction more likely. Children also have less gastric motility. For safety, pediatric patients often have stricter nothing by mouth guidelines before anesthesia – frequently no solids for 8-12 hours and no liquids for 4-6 hours.
| Age | Fasting Guidelines |
|---|---|
| Newborns 0-6 months | Breast milk: 4 hours Formula: 6 hours |
| 6-36 months | Breast milk: 6 hours Formula: 6-8 hours Solids: 6-8 hours |
| > 36 months | Solids: 8 hours Liquids: 8 hours |
Should I take my medications before anesthesia with sips of water?
Most medications can be taken with a small sip of water up to 2 hours before anesthesia. But always check with your anesthesia team for specific guidelines based on your health history and surgical needs.
Some medications may need to be held before surgery. Others may be adjusted or administered IV after anesthesia is given.
Summary
Key takeaways about eating and drinking before anesthesia:
- Follow fasting guidelines to allow complete gastric emptying before anesthesia
- Fast from solids for 8 hours – Avoid foods, milk, snacks
- Fast from clear liquids for 2 hours – Stick to water, black coffee, diluted juice
- Eat light, low-fat meals up until 8-10 hours pre-op
- Stay hydrated with clear fluids until your liquid fast begins
- Avoid gum, mints, candy, and carbonated beverages before anesthesia
- Infants and children may have longer fasting times for safety
Following an appropriate fasting schedule before anesthesia minimizes risks and improves safety. If you have any questions about eating or drinking before your procedure, discuss them with your anesthesia care team. They can provide personalized guidelines for optimal fasting based on your health status and surgery needs.
