Following lengthy and difficult deliberations, which took place over a period of almost 2 years, we have decided on a plan to replace the sphygmomanometers currently being used at hospitals and clinics. The function of the unit should be identical to the existing mercury sphygmomanometer so that a nurse does not have to alter his/her working habits. No bells, whistles or automatic measurement functions, which are usually so tempting to us, because we believe that the oscillometric algorithms we have advanced as the forerunner in this field are as accurate and reliable as any measurement performed by doctors and nurses using mercury sphygmomanometers with the Korotokov method.

Since this decision was made, Shinobu Ozaki and his people began visiting medical facilities to interview doctors and nurses to learn more about exactly how they use their sphygmomanometers. At the start of their research they were still wondering and asking themselves, “Why do we have to design a device that is going to disappear as more and more electronic instruments with automatic measurement are going to be made available?” “Besides A&D’s goal has been to create an electronic blood pressure monitor that is reliable, economical and easy to use for every medical situation, either at home or in a hospital.” However, as they observed the way nurses and doctors used their sphygmomanometers, they came to understand the need for human interaction in medical practices and realized that generally listening for Korotokov sounds means more than simply measuring blood pressure. It can be a means of communication between a nurse or doctor and his/her patient. They also learned that there are needs for improving existing sphygmomanometers. For instance, the mercury column is too slow to respond to the pumping speed of a nurse. There is a time lapse between the pump and the pressure indication on the scale because of the mass of the mercury column, which results in pumping up to unnecessary higher pressure levels.

“It was an eye-opening experience because we realized that there was a need for some basic improvement in the current sphygmomanometer that has been in use for years.” Ozaki also added, “Nurses want better looking units. They are tired of carrying around cumbersome iron units. They are functional but very old-fashioned, heavy and bulky.”

Therefore, the original concept of merely replacing the mercury had to be altered to a more ergonomically friendly design. We also looked at improving the functionality of the unit to respond in real time while inflating and exhibit the same reactions as the mercury during deflation or measurement. Technical challenges and the need for an innovative design faced our R&D team. They knew that conventional LCD’s or liquid crystal displays are too slow to show changes in pressurization in real time. More appealing and more manageable casing to suit the current medical environment has also posed as big a challenge as developing the electronics.

While he monitored wounded or dying soldiers in the battlefield, he came to discover certain sounds could be heard during the depressurization of the arteries, which later became known as “Korotokov sounds”. His findings revolutionized the then existing diagnosis of the heart and vessels.