Children with congenital heart disease are at high risk for malnutrition. Standardisation of feeding protocols has shown promise in decreasing some of this risk. With little standardisation between institutions’ feeding protocols and no understanding of protocol adherence, it is important to analyse the efficacy of individual aspects of the protocols.

Adherence to and deviation from a feeding protocol in high-risk congenital heart disease patients between December 2015 and March 2017 were analysed. Associations between adherence to and deviation from the protocol and clinical outcomes were also assessed. The primary outcome was change in weight-for-age z score between time intervals.

Increased adherence to and decreased deviation from individual instructions of a feeding protocol improves patients change in weight-for-age z score between birth and hospital discharge (p = 0.031). Secondary outcomes such as markers of clinical severity and nutritional delivery were not statistically different between groups with high or low adherence or deviation rates.

High-risk feeding protocol adherence and fewer deviations are associated with weight gain independent of their influence on nutritional delivery and caloric intake. Future studies assessing the efficacy of feeding protocols should include the measures of adherence and deviations that are not merely limited to caloric delivery and illness severity.