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Preoperative Fasting Guidelines


Ingested Material

Minimum Fasting Period

clear liquids 2 hours
breast milk 4 hours
formula 6 hours
milk (non-human) 6 hours
light meal 6 hours
solids 8 hours

These are the guidelines recommended by the American Society of Anesthesiologists. The guidelines are applied in each individual case according to the clinical judgment of the attending anesthesiologist.

These recommendations apply to healthy patients who are undergoing elective surgery. They are not intended for women in labor. The fasting periods apply to all ages.

Examples of clear liquids are water, fruit juices without pulp, carbonated beverages, clear tea, and black coffee.

Since non-human milk is similar to solids in gastric emptying time, the amount ingested must be considered when determining an appropriate fasting period.

A “light meal” consists of plain toast and clear liquids. Meals that include fried or fatty foods or meat will increase the acid in your stomach and also may prolong the time it takes your stomach to empty.

You will be given specific instructions on preoperative fasting for both liquids and solids before your surgery.