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Key Points

  • Pediatric preoperative fasting guidelines were developed to reduce the risk of pulmonary aspiration and the severity of pulmonary complications should aspiration occur.
  • National guidelines recommend a “6-4-2” rule for preoperative fasting, meaning a minimum of 6-hour fast for solid food or formula, 4 hours for breast milk, and 2 hours for clear fluids.
  • Recently updated recommendations encourage shorter actual fasting times while still allowing sufficient fasting times for safety.

Introduction

  • The goal of preoperative fasting recommendations is to reduce the risk of aspiration and the severity of pulmonary complications should aspiration occur.
  • Most national guidelines recommend a “6-4-2” rule for preoperative fasting, meaning a minimum of 6-hour fast for solid food or formula, 4 hours for breast milk, and 2 hours for clear fluids.1,2
  • In infants and children, these recommendations often result in actual fasting times that far exceed the safety margin and may result in hunger, thirst, and patient and caregiver distress.3
  • There has been a shift in focus to minimal safe fasting times and encouraging intake up until that time.

Solids and Nonhuman Milk

  • The American Society of Anesthesiologists (ASA) practice guidelines on preoperative fasting1, as well as the European Society of Anaesthesiology and Intensive Care (ESA-IC) preoperative fasting guidelines in children,2 recommend that solid food can be ingested until 6 hours before procedures requiring general anesthesia, regional anesthesia, or procedural sedation and analgesia.
  • A meal of fried food, fatty food, or meat may require additional fasting times (e.g., 8 hours or more).
  • While there is some evidence that 4 hours of fasting after a light meal is safe and well-tolerated in healthy children, there are no large studies confirming the lack of increase in aspiration rates, and the definition of a light meal may be a challenge to deliver and evaluate consistently.2

Breast Milk and Formula

  • The ASA practice guidelines recommend a 4-hour fasting period for breast milk and a 6-hour fasting period for formula before procedures requiring general anesthesia, regional anesthesia, or procedural sedation and analgesia.1
  • The ESA-IC fasting guidelines recommend that breast feeding be encouraged until 3 hours prior to anesthesia.2 This was based on 9 observational studies on gastric emptying after breast milk feeds in infants and young children. Their recommendations are the same (i.e., 3 hours) even for fortified breast milk.
  • The ESA-IC fasting guidelines suggest that for infants, formula may be given safely up until 4 hours prior to anesthesia; however, larger studies are necessary to be confident of the safety in regard to aspiration.2

Clear Fluids

  • The ASA recommends that clear fluids may be ingested for up to 2 hours before elective procedures requiring general anesthesia, regional anesthesia, or procedureal sedation and analgesia.1
  • Institutions that have been using shorter clear fluid fast times of 1 hour, or even 0 hours, have shown no increased risk of aspiration with this more liberal clear fluid fasting times and have shown a marked decrease in actual fasting times.4,5
  • This evidence has been shifting international consensus from a 2-hour to a more liberal 1-hour clear fluid fasting policy, which was proposed in a joint statement by the Association of Paediatric Anaesthetists of Great Britain and Ireland, the European Society for Pediatric Anesthesiology, and the Association of French Speaking Paediatric Anaesthetists (ADARPEF).6
  • This policy has seen been endorsed by the European Society of Anaesthesiology,2 the Canadian Pediatric Anesthesia Society, and the Society for Pediatric Anaesthesia of New Zealand and Australia.

References

  1. Practice guidelines for preoperative fasting and the use of pharmacologic agents to reduce the risk of pulmonary aspiration: Application to healthy patients undergoing elective procedures: an updated report by the American Society of Anesthesiologists Task Force on preoperative fasting and the use of pharmacologic agents to reduce the risk of pulmonary aspiration. Anesthesiology. 2017; 126(3):376-93. PubMed
  2. Frykholm P, Disma N, Andersson H, et al. Pre-operative fasting in children: A guideline from the European Society of Anaesthesiology and Intensive Care. Eur J Anaesthesiol. 2022; 39:4. PubMed
  3. Engelhardt T, Wilson G, Horne L, Weiss. Are you hungry? Are you thirsty? Fasting times in elective outpatient pediatric patients. Paediatr Anaesth. 2011; 21:964–968. PubMed
  4. Andersson H, Zaren B, Frykholm P. Low incidence of pulmonary aspiration in children allowed intake of clear fluids until called to the operating suite. Paediatr Anaesth. 2015; 25:770–777. PubMed
  5. Newton RJG, Stuart GM, Willdridge DJ, et ak. Using quality improvement methods to reduce clear fluid fasting times in children on a preoperative ward. Paediatr Anaesth. 2017; 27:793–800. PubMed
  6. Thomas M, Morrison C, Newton R, et al. Consensus statement on clear fluids fasting for elective pediatric general anesthesia. Paediatr Anaesth. 2018; 28:411–4. PubMed