History of continuous noninvasive arterial pressure

Such sphygmographs led a shadowy existence in the past, while Riva Rocci's upper arm blood pressure measurement started its triumphant success over 100 years ago.

In recent times, CNAP measurement introduced by Jan Penáz in 1973 enabled the first recording of noninvasive beat-to-beat blood pressure resulting in marketed products such as the Finapres™ device and its successors.

Prior to quantitative measurement, which was applied in medicine in the 19th century, diagnostic possibilities of hemodynamic activities had been limited to qualitative sensing of pulse through palpation.

The introduction of the stethoscope and the methods of auscultation by René-Théophile-Hyacinthe Laennec in 1816 changed the medical behavior consistently and forced the need of quantitative hemodynamic measurements.

[5] In his famous book “La méthode graphique“ (1878) and his studies with the photographic gun, Marey's work was related to cardiovascular movements of heart and vessels.

[6] Besides Marey's sphygmograph, a device developed by the Austrian Samuel von Basch attracted attention and was introduced in Europe in 1880 .

Since the finding of the characteristic sounds by the Russian Nikolai Sergejev Korotkoff in 1905, the upper arm method also allows the registration of absolute diastolic blood pressure.

[12] One year after Riva-Rocci's findings, Leonard Erskine Hill and Harold Barnard reported blood pressure monitoring during anesthesia for the first time.

It is an instantaneous, continuous measure for arterial blood pressure, which is the basic principle of the so-called “vascular unloading technique”.

[15] The Czech physiologist Jan Peňáz introduced the vascular unloading technique on the finger in 1973 by means of an electro-pneumatic control loop.

However, the changes in arterial diameter and in wall tension due to vasoconstriction and vasodilatation make a long-term measurement with this single control loop almost impossible, since the true unloading of the arterial wall is easily lost [17] Therefore, groups in the Netherlands,[18][19][20][21][22] Japan,[23][24][25][26][27][28][29] Australia[30] and Austria[31][32][33] have improved the Peňáz principle of vascular unloading.

[citation needed] Starting in 1996, an Austrian research group has developed a completely digital approach of the method.

In order to obtain a stable blood pressure signal, the tonometric sensor must be protected against movement and other mechanical artifacts.