- Design
- Systematic review and meta-analysis of randomised and non-randomised studies
- Population
- 580,197 children under 18 having anaesthesia or sedation
- Primary outcome
- Pulmonary aspiration
- Effect
- 0.03% in both policies; RR 0.77 (0.40–1.47)
A meta-analysis pooled 33 studies of 580,197 children under 18 having general anaesthesia or sedation, comparing liberal clear fluid fasting (under two hours) with conventional fasting (two hours or more).
Pulmonary aspiration occurred in 0.03% under both policies, about 3 in 10,000 children. In the 14 studies that compared the policies directly (475,399 children), there was no difference in risk (RR 0.77, 95% CI 0.40 to 1.47). Vomiting without aspiration was also similar (0.76% vs 0.99%). Certainty was very low, largely because most data are observational and events are rare.
Prolonged clear fluid fasting leaves children thirsty, distressed and sometimes hypoglycaemic or hypovolaemic, and in practice fasts often run far longer than the policy states. Several European paediatric anaesthesia bodies already endorse a one-hour clear fluid fast.
These data add reassurance for units adopting or keeping a shorter clear fluid policy for children, while individual exceptions (delayed gastric emptying, bowel obstruction) still apply.
- Consider allowing clear fluids up to one hour before anaesthesia in otherwise well children.
- Encourage children to drink rather than simply permitting it, so fasts do not run long.
- Keep individual exceptions for delayed gastric emptying or obstruction.
- Audit actual fasting times, which often exceed the policy.
Why it matters
It reassures units that shorter fasts do not trade comfort for aspiration risk.
Don't overread it
Very low certainty; aspiration is too rare for these data to exclude a small difference.
The statistics, in plain English
A risk ratio of 0.77 with an interval from 0.40 to 1.47 is compatible with anything from 60% fewer to 47% more aspirations. Because the baseline risk is 3 in 10,000, even the upper bound means a very small absolute difference.
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