Properties of Australian thickened formulae for infants and children: Influence of preparation and nutritional content on IDDSI properties

Between 30% and 50% of infants and children with pediatric feeding disorders demonstrate oropharyngeal aspiration. Thickening fluids are a compensatory strategy that is commonly recommended by speech pathologists for the management of oropharyngeal aspiration. Ongoing variability in the preparation of thickened fluids across infant formulas and healthcare facilities continue to limit the standardization of the preparation of thickened infant and pediatric formulas. No studies exist which examine the influence of nutritional properties of different infant formula types on IDDSI thickness levels. Our study aimed to describe the impact of standardized resting times; and understand the influence of nutritional properties on a variety of ready-to-feed liquid and powder-based Australian thickened formulae. A total of 27 ready-to-feed liquid and powder-based formulas were tested for viscosity level at baseline and when thickener was added on at least two trials. Frequency counts and percentages were used to describe categorical data. Logistic regression was used to model the binary outcome and calculate the odds ratios and their 95% confidence intervals. A total of 18 formulas proceeded to IDDSI flow testing of at least two trials because 7 formulae tested as slightly or mildly thick at baseline; while 2 formulae only had one trial of IDDSI flow testing completed. Of the 18 formulae tested, 72.22% (13/18) of commonly used powder-based and ready-to-feed formulas in Australia thickened to IDDSI slightly thick (level 1) were prepared in a standardized manner and allowed to rest for 5 min. Formulas with higher protein totals were more likely to thicken sufficiently (AOR: 7.45; 95% CI: 2.06-26.89), while formulas with higher sugar totals or those used for enteral feeds were less likely to thicken sufficiently (AOR: 0.02; 95% CI: 0.01-0.29). There was good test-retest reliability (ICC: 0.76; 95% CI: 0.22-0.97), indicating that standardizing the preparation of thickened fluids was consistently achievable. Given that not all formulae were observed to thicken to the intended consistency using standardized preparation and resting time, this study highlights the importance of using the IDDSI Flow Testing Method regularly in practice when recommending thickened infant formula recipes for managing aspiration in infants and children.