Guidelines have permitted clear fluids until two hours before anaesthesia for decades. Median fasting times worldwide remain around twelve hours. The gap is not a guideline problem; it is a process problem, and it is reproduced every day by the way lists are organised and instructions are given.
The mechanism is simple. A patient told 'nil by mouth from midnight' for an afternoon slot fasts for fourteen hours. Nobody intends it, and nobody owns it: the surgeon's letter says midnight, the ward follows the letter, and the anaesthetist meets the consequence — thirst, headache, hypotension on induction, a higher vasopressor requirement, worse postoperative nausea, and in older patients a real contribution to delirium. Children and diabetic patients suffer most.
The fix is to give a permission rather than a prohibition. Tell the patient, in writing, to drink clear fluids until two hours before their scheduled time, and to keep drinking until told to stop. Put water or oral rehydration solution at the bedside on the ward. When a list overruns, someone has to actively offer fluids again to the patients further down it — that is the step that never happens unless it is somebody's named job.
The usual objection is aspiration risk, and it deserves a straight answer: aspiration in elective patients is rare, and the evidence base for it is too thin to support twelve-hour fasting. Where delayed gastric emptying is genuinely suspected — significant gastroparesis, bowel obstruction, an emergency — the calculus changes, and increasingly gastric ultrasound can answer the question directly rather than by assumption.
- Write the instruction as a permission to drink until two hours before the scheduled time, not as 'nil by mouth from midnight'
- Make re-offering clear fluids to later patients somebody's named responsibility when a list overruns
- Keep clear fluids physically at the bedside; an instruction without a jug does not work
- Use gastric ultrasound where delayed emptying is genuinely in question rather than fasting the patient by default
- Audit actual fasting times, not policy — the two are rarely the same
Why it matters
The two-hour rule has been policy for decades and is still not practice, and the harm falls on the patients least able to absorb it.
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