Pre-operative fasting guidelines: an update

Area of Science:

• Anesthesiology
• Gastroenterology
• Evidence-based medicine

Background:

• Current international guidelines recommend restricted pre-operative fasting, with clear fluids allowed up to 2 hours and light meals up to 6 hours before anesthesia.
• Recent advancements include pre-operative oral nutrition with carbohydrate-rich beverages, shown to be safe regarding gastric volume and acidity.
• These practices are generally extended to children and non-laboring pregnant women, with specific allowances for milk feeding in infants.

Framework:

• New consensus-based Scandinavian guidelines for pre-operative fasting have been developed based on available literature.
• The guidelines advocate for more liberal fasting routines compared to previous practices.

Implementation:

• Clear fluids are generally permitted up to 2 hours before anesthesia.
• Light meals are allowed up to 6 hours prior to anesthesia.
• Specific recommendations exist for infants (<6 months), allowing breast or formula milk up to 4 hours before anesthesia.

Implications:

• The guidelines address the need for further research into the application of liberal fasting in specific patient populations, including those with functional dyspepsia or diabetes mellitus.
• Controversial areas requiring more investigation include fasting for emergency patients, women in labor, and procedures under deep sedation.
• Additional research is essential to advance towards completely evidence-based pre-operative fasting guidelines.