The use of differential pressure as an inferred measurement of a liquid's rate of flow is well known. Differential pressure flowmeters are, by far, the most common units in use today. Estimates are that over 50 percent of all liquid flow measurement applications use this type of unit.
Between 1% and 15% of people globally are affected by kidney stones at some point in their life. In 2013, 49 million cases of occurred, resulting in about 15,000 deaths. They have become more common in the Western world since the 1970s. Generally, more men are affected than women.
Chronic kidney disease is increasing in the United States, with more than 20 million Americans now suffering with it, according to the American Society of Nephrology. This occurs when a person's kidneys become damaged and can't filter blood as they should.