NPO Guidelines

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NPO Guidelines - Empty Tummy Tactics

  • Purpose: Prevent pulmonary aspiration of gastric contents during anesthesia, reducing risk of complications (e.g., aspiration pneumonitis).

  • Pathophysiology of Aspiration:

    • Aspiration occurs when gastric contents enter the lungs.
    • Severity depends on volume and acidity of aspirate.
    • Critical thresholds: Gastric volume > 0.4 ml/kg (or > 25 ml) and pH < 2.5.

    ⭐ Mendelson's syndrome is defined by aspiration of gastric contents with pH < 2.5 and volume > 0.4 ml/kg (typically > 25 ml).

  • Factors ↑ Aspiration Risk:

    • Full stomach (e.g., recent meal, gastroparesis).
    • Impaired protective airway reflexes.
    • GERD, hiatal hernia.
    • Obesity.
    • Pregnancy.
    • Emergency surgery.
    • Diabetes, opioid use.
    • Difficult airway or intubation.

Factors increasing aspiration risk during anesthesiaoka

NPO Guidelines - Clocking Clear & Solids

Nil Per Oral (NPO) guidelines are crucial to reduce aspiration risk during anesthesia. American Society of Anesthesiologists (ASA) recommendations are standard:

Intake TypeMinimum Fasting Period
Clear Liquids2h
Breast Milk4h
Infant Formula6h
Non-human Milk6h
Light Meal (e.g., toast, clear liquids)6h
Heavy/Fried/Fatty Meal8h or more
  • 2h for clear liquids.

  • 4h for breast milk.

  • 6h for infant formula, non-human milk, or a light meal.

  • 8h (or more) for a heavy, fried, or fatty meal (includes meat).

  • Chewing Gum/Hard Candy: Often allowed until just before induction if not swallowed. Gum should be removed pre-induction. Always confirm institutional policy.

⭐ Clear liquids include water, fruit juices without pulp, carbonated beverages, clear tea, and black coffee. Importantly, milk (even in tea/coffee) is NOT considered a clear liquid and requires a longer fasting duration.

NPO Guidelines - Special Patient Plays

  • Pediatrics: Age-specific fasting crucial to prevent aspiration.
    • Clear liquids (water, pulp-free juice): 2h
    • Breast milk: 4h
    • Infant formula: 6h
    • Non-human milk / Light meal (e.g., toast): 6h
    • Solids (fried/fatty food, meat): 8h
  • Pregnancy: Hormonal changes & mechanical pressure ↑ aspiration risk.
    • Labor: Clear liquids often permitted; assess individually.
    • Elective C-section: Solids 6-8h, clear liquids up to 2h pre-induction.

    ⭐ For elective cesarean delivery, solids should be withheld for 6-8 hours; clear liquids up to 2 hours pre-induction are generally safe in uncomplicated pregnancies.

    • Emergency C-section: Treat as full stomach; RSI essential.
  • Diabetes Mellitus: Potential for gastroparesis. Consider longer NPO; assess gastric emptying if concerned. Individualize based on severity and glycemic control.
  • GERD / Obesity / Hiatal Hernia: Higher risk of regurgitation/aspiration. Individualize NPO; often extended fasting. Pharmacological aids (e.g., H2 blockers, PPIs) beneficial.
  • Emergency Surgery: Always assume full stomach, irrespective of last meal. Rapid Sequence Intubation (RSI) is standard to secure airway.
  • Pharmacological Aids (Aspiration Prophylaxis):
    • Antacids (e.g., sodium citrate): Neutralize existing gastric acid.
    • H2 Blockers (e.g., ranitidine): ↓ Acid volume & production.
    • PPIs (e.g., omeprazole): ↓ Acid production (less effective for acute use).
    • Prokinetics (e.g., metoclopramide): ↑ Gastric emptying; use cautiously (contraindications, side effects).

High‑Yield Points - ⚡ Biggest Takeaways

  • Clear liquids (water, black coffee/tea, pulp-free juices) require a 2-hour fast.
  • Breast milk digestion is faster; requires a 4-hour fasting period.
  • Infant formula and non-human milk necessitate a 6-hour fast.
  • A light meal (e.g., toast and clear liquid) also requires 6 hours of fasting.
  • Heavy or fatty meals significantly delay gastric emptying, mandating an 8-hour fast.
  • NPO aims to reduce pulmonary aspiration risk; oral meds often allowed with water sips 1-2 hours pre-op.

Practice Questions: NPO Guidelines

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Mendelsons syndrome is:

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Flashcards: NPO Guidelines

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A patient with poorly controlled DM/HTN would be classified under ASA _____

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A patient with poorly controlled DM/HTN would be classified under ASA _____

III

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