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Fasting Guidelines 

 

Adapted from American Society of Anesthesia 2011 Fasting Guideline & 2017 CAS Guidelines to practice of anesthesia   Full guidelines here: 

 

 

 

 

 

 

Preoperative Fasting Status 

 

  • Adults: 

    • Clear Fluids: 2 hrs 

    • Light meal & Non-human mild: 6 hrs 

    • Fried fatty meal/meat: 8 hrs 

  • Pediatrics:  

    • Breast milk: 4 hrs 

    • Formula: 6 hrs 

 

 

Pharmacologic Therapy 

  • Gastrointestinal Stimulants 

    • DO NOT USE ROUTINELY if average risk of reflux/aspiration 

    • Maxeran

      • good evidence for gastric emptying 

      • no good evidence for reducing acidity 

  • Gastric Acid Reducing Agents 

    • DO NOT USE ROUTINELY if average risk of reflux/aspiration 

    • All H2 receptor antagonists (cimetidine, ranitidine, famotidine) effective for reducing gastric volume & acidity.  Miller says Ranitidine most effective for reducing the gastric volume. 

    • PPI effective for reducing gastric volume & acidity 

    • Insufficient evidence to decide between H2-blocker VS PPI 

  • Antiemetics

    • DO NOT reduce the risk of aspiration in otherwise normal patients

    • Should NOT be routinely used

    • Effective only for PONV 

  • Anticholinergics

    • NOT recommended routinely 

    • Equivocal evidence that they reduce gastric volume or acidity 

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