What are the 2026 American Society of Anesthesiologists (ASA) Nil Per Os (NPO) guidelines for preoperative fasting?

2026 ASA NPO Guidelines

The most current ASA preoperative fasting guidelines (last updated 2011, still in effect) recommend: clear liquids up to 2 hours before anesthesia, light meals up to 6 hours before, and fatty/fried foods up to 8 hours before elective procedures in healthy patients. 1, 2

Clear Liquid Guidelines

• Clear liquids may be consumed up to 2 hours before elective procedures requiring general anesthesia, regional anesthesia, or procedural sedation in otherwise healthy patients 1, 2
• Acceptable clear liquids include water, fruit juices without pulp, carbonated beverages, clear tea, and black coffee (no alcohol) 1, 2
• Meta-analysis demonstrates that 2-4 hour fasting for clear liquids results in smaller gastric volumes and higher gastric pH compared to prolonged fasting 2
• The volume of clear liquid ingested is less critical than ensuring no particulate matter is present 3

Breast Milk and Infant Formula

• Breast milk may be consumed up to 4 hours before elective procedures in neonates and infants 2
• Infant formula requires a minimum 6-hour fast before elective procedures for all age groups (neonates, infants, children, and adults) 1, 2

Solid Food Restrictions

• Light meals (such as toast with clear liquid) require a minimum 6-hour fast before elective procedures 1, 2
• Fried or fatty foods or meat require a minimum 8-hour fast due to prolonged gastric emptying time 1, 2
• Both the amount and type of food must be considered when determining appropriate fasting periods 1
• Nonhuman milk is treated similarly to solids, requiring 6 hours of fasting 1

High-Risk Populations Requiring Modified Approach

• Patients with gastroesophageal reflux disease or known delayed gastric emptying require longer fasting periods than standard recommendations 2, 4
• Patients with morbid obesity, diabetes mellitus, difficult airway, or other high-risk features warrant case-by-case restrictions beyond standard guidelines 3
• Patients with Child class C cirrhosis should not fast due to risk of encephalopathy, ascites, and metabolic decompensation 2
• Individuals with diabetes mellitus are at high risk of severe hypoglycemia during extended fasting and should not fast without close medical supervision 2

Medication Management During Fasting

• Non-nourishing medications via parenteral routes, suppositories, and inhalers are allowed during fasting periods 2
• Oral medications should be rescheduled to non-fasting periods when possible 2

Pharmacologic Agents

• Gastrointestinal stimulants (such as metoclopramide) should not be routinely administered before elective procedures in patients without apparent increased risk for pulmonary aspiration 1
• Metoclopramide reduces gastric volume but has equivocal effects on gastric acidity 1
• Routine preoperative antacids are not recommended for healthy patients, though they increase gastric pH, the literature does not demonstrate decreased morbidity or mortality 1

Common Pitfalls to Avoid

• Prolonged fasting beyond recommended times offers no additional protection against aspiration and causes unnecessary patient discomfort, thirst, hunger, and potential hypoglycemia (especially in children) 1, 5, 6
• The traditional "NPO after midnight" order is outdated and inconsistent with current evidence-based guidelines 6
• Actual fasting times often exceed instructed times due to scheduling changes and communication deficiencies, resulting in patients fasting 12-20 hours unnecessarily 6

Important Caveats

• These guidelines apply specifically to healthy patients undergoing elective procedures 1
• Emergency surgery patients require more conservative fasting protocols 2
• The incidence of clinically significant aspiration during elective procedures is extremely low (1.4-6.0 per 100,000 anesthetics) when guidelines are followed 5
• Clear fluids empty the stomach within 60-90 minutes, making prolonged fasting physiologically unnecessary 4