Abstract

The Venturi meter which has long been used in hydraulics is here applied to the measurement of volume flow of blood through vessels. One method is by inserting an accurately calibrated Venturi meter made of glass into the circulation. This method requires an anticoagulant, but is accurate and sensitive to slight changes in flow. Another method is to produce a constriction in a vessel by means of a ligature near a branch, which can be used as a side tube, thus transforming the vessel itself into a Venturi meter. The latter method is subject to greater error in calibration for absolute flows, but is sensitive for estimating slight changes in the rate of flow and does not require the use of an anticoagulant.