Imagine this scenario. Dialysis as a therapy is just starting to “click”. Treatments are available in one of two modalities- coil or flat plate. The coil (schematic shown) system reminds one of a giant washing machine, with a bathing solution of warm salt water, bubbled carbon dioxide, and a plastic device (looking like a car “air filter”) inserted inside this mess, through which passes your blood. The “air filter” is a membrane that separates the solution from your blood; the impurities from your blood are whisked away by the solution. The flat plate (schematic shown) involves two sets of membranes placed inside of gaskets and blocks of polypropylene (a plastic) . Your blood flows through the membranes and on the other side (of the membrane) is a salt water solution, that “catches” the impurities in your blood. The coil is a manufactured device; the flat plate requires a technician to prepare the membranes, insert them between the gaskets and the blocks, and then tighten some very big bolts. The salt water solution (called dialysate) is produced (typically) from a salt packet provided by a small company in New York, which is then mixed into water. Lots of preparation time for each treatment.
Treatment times are 12 hours. They happen every other day. Your blood gets purified over the 12 hours. In between, your diseased kidneys afford a buildup of impurities and toxins in your body. Not very efficient. Your blood concentrations have a seesaw effect- no (or little) toxins or impurities, followed by a slow buildup over the next two or three days. [Note: this link is to a simulated graph.]
Many researchers are looking to cut the 12 hour treatment period. It’s way too long. About the same time, one of the prime innovators determines that with the current equipment, one can substitute the buffer in dialysate (which was bicarbonate, the same as your blood’s buffer) for another (acetate). Why? Because acetate is soluble in water and bicarbonate is not. (That’s why carbon dioxide was being bubbled into the solution; to maintain the bicarbonate level in the dialysate.) He approaches the small company that makes the salt packets to have it produce his new invention- a one gallon concentrate that will cut preparation time (and errors) dramatically. The president of the small firm is convinced no one in their right mind will want to pay to ship a gallon of water/salt mixture to save time. He believes his product is the best solution.
Too bad. The inventor goes to a different company- it jumps at the opportunity. Lo and behold, the small company stays small; the new one becomes one of the kings of the business.
The moral of this part of the story- always examine your basis. Always speak with your customers to find out what they want- not what you think they want. (And, this little change (acetate v. bicarbonate) will create new problems down the road… more on this problem later.)