Determinant factors of the viscosity of enteral formulas: basic analysis of thickened enteral formulas.

Background: Thickened enteral formula (TEF), which is made by adding thickener to enteral formula, has been used mainly in Japan to reduce the incidence of clinical complications associated with enteral nutrition. However, the optimal viscosity of TEF needed to achieve a high efficiency is different for each medical complication and for individual patients.

Methods: The viscosity of TEF, which consists of enteral formula and thickener, was determined by 5 factors: (1) formula energy density, (2) formula temperature, (3) stirring speed, (4) stirring time, and (5) time elapsed since preparation. Then, the changing index (CI) was calculated for each of the 5 factors to determine which exerts the most influence on TEF viscosities.

Results: The most influential factor (CI ≥-50%) for the decrease in TEF viscosity was formula energy density. In contrast, the most influential factors (CI ≥50%) for the increase in TEF viscosity were stirring time and time elapsed since preparation.

Conclusion: The results of this study indicate that formula energy density, stirring time, and time elapsed since preparation are the most influential factors to consider during manipulation of TEF viscosity.