One might ask, “What is so important about blood flow?” The answer is clear. Blood flow is the flow of life!

As blood flows through the 66,000 mile human circulatory system it delivers nourishment and oxygen to every cell to use for metabolism. Blood then removes the waste products from that metabolism. It enables life. Simply, when blood flow is cut off, life ends. 

Yet, why is blood flow so often disregarded or ignored? Simply stated, devices and technologies to reliably measure blood flow were unavailable until the mid-twentieth century. In their stead, surrogate measurement modalities such as pressure became entrenched and are still used primarily today. 

Yet pressure, routinely used to assess hemodynamic function, does not always correlate with flow. Pulses, visual and tactile, are felt and observed, but they do not provide information about true flow. Angiography shows anatomical structure, not quantitative function. Doppler technology measures the velocity, not the volume of flow. All these surrogates for true flow do not provide quantitative true volume flow data. True volume blood flow is precisely measured by Transonic devices. It is a quantitative, not a subjective (qualitative) measure of hemodynamic function.

Just as a pilot must learn to fly with instruments in order to fly safely, the researcher and clinician must also rely on real numbers, not impressions, to provide functional information to arrive at objective conclusions. Blood flow in mL/min or L/min as measured by Transonic devices provides that quantitative data. Blood flow is life’s quintessential vital sign.