Issues in medical measurements

Most of medical measurement techniques are extended from different non-medical fields. Glucometry was developed from sugar measurement in apples; X-ray is used in crystallography, while MRI is employed in numerous industrial applications. These methods were transferred in medicine wherever direct measurements of physical or chemical parameters were possible. Non-invasive blood pressure measurement is the only application where direct measurement methods from other fields could not be applied for practical and ethical reasons. Direct measurement of blood pressure is invasive, and, as such, it has a very limited clinical value. On the other hand, we know little about the physics of blood pressure. Indeed, the nature of the Korotkov sound is still barely investigated, although millions of measurements are made daily based on it. The pulsatile flow of smart fluids in collapsible tubes has yet to benefit from a rigorous scientific description. Non-invasive blood pressure measurement is improperly called "measurement" since it is more an estimation which is derived from the correlation between the blood pressure and external phenomena, such as the Korotkoff sounds in the case of the method with the same name. The validity of this approximation is determined by factors such as the state of the subject, and influences the accuracy of the method at hand. To improve the robustness and trustworthiness of blood pressure estimation for broader categories of subjects and conditions, our team conceived and implemented several algorithms that were added to or complemented the oscillometric method, the most wide-spread automated technique nowadays.