Objective To examine the impact of an implementation program on adherence to a guideline for the management of acute gastroenteritis.

Design Using four retrospective audits over a 10-year period, the authors examined the change in practice and maintenance of that change following a targeted implementation program for the clinical guideline.

Setting Tertiary children's hospital in South Wales.

Participants 447 children aged less than 5 years, admitted to hospital with acute gastroenteritis, comprising four cross-sectional samples (106 in 1999, 153 in 2002, 99 in 2004, 89 in 2009).

Main outcome measures Age of child, hydration status, method of rehydration and duration of admission, for each audit, with an implementation strategy delivered after the second audit.

Results In 1999 and 2002, intravenous rehydration was used in 20% and 15% of cases, respectively. After the implementation program in 2004, compared to 1999, there was a significant decrease in the intravenous rehydration rate to 4% in 2004 (p<0.001); in 2009 the intravenous rehydration rate was maintained at a low level of 6% (p<0.001).

Conclusion It was only after the implementation program that a change in practice was achieved. Once change had been accepted, it was maintained even in the absence of targeted training. Audit does not improve clinical practice unless, in addition, there is a clear, succinct guideline with an implementation programme in place.