Line Spread as a Visual Clinical Tool for Thickened Liquids

Abstract

Preparing modified liquids to a target level of consistency is critical to patients' nutritional care. This study examined the relationship of line spread (i.e., the distance a liquid flows) to viscometer measurements for a variety of product/liquid combinations and determined if flow distance visually differentiated nectar-thick versus honey-like consistency. Combinations of 4 thickening products (3 starch-based and 1 gum-based thickener) prepared with 6 serving-temperature liquids that had various levels of fat, fiber, and added nutrients were tested. A total of 32 product/liquid combinations tested within the target range of 80-800 centipoise (cP). Measurements were recorded using line spread and a Brookfield RVDV-II+ viscometer. Nectar-thick and honey-like consistencies significantly differed in their degree of line spread. Using our line spread apparatus, a value of 4.5 cm differentiated between nectar-thick and honey-like consistencies. There was an inverse correlation (-.75) between viscometer data and line spread results. That is, high viscosity values represented samples with less flow distance (line spread), and low viscosity values represented samples with more flow distance. Line spread appears to be a quick, objective, and visual method that might be used to help patients and their caregivers achieve more accurate and consistent thickened liquid preparation.