Why patients are kept NPO and fluid administered intravenously before the surgeries?

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E6 Nursing Fundamentals Potter Perry 12e Part 6 pp. 185-187, 183-185
E6 Nursing Brunner Adult Health 3SA Vol 1 Part 1 p. 64-66
Practise the full NORCET 3 - 2022 (Shift-1)
Attempt every question from this paper in a timed mock, then review the full solution for each one.