[Epistemological focus on sphygmomanometry].

In the XVIII century, the English naturalist Stephen Hales started to apply blood sphygmomanometry in animals. Direct recording of the blood pressure was first applied, in the XIX century, by AE Chauveau and JLM Poiseuille. However, it was not until 1856 that it was possible to perform a direct determination of blood pressure in humans by means of a device designed by Faivre. The first sphygmomanometer appeared at the end of the XIX century. The physician Samuel K. von Basch, native of Prague and who lived a few years in Mexico, fabricated successively three models of sphygmomanometers. The first (1881), with a mercury column, proved to be the most practical and useful. This instrument inspired the sphygmomanometer of the Italian physician Scipione Riva-Rocci who presented it in 1896. His sphygmomanometer, supported on the Vierordt principle, could measure manometrically the force needed to stop the pulse wave. Thanks to the research of Russian physician N. Korotkoff, the auscultatory method was added to sphygmomanometry. During the XX century other instruments to measure blood pressure were fabricated: the Pachon's and Plesch's oscillometers, as well as the aneroid manometer. On the other side, the use of direct tensional recordings has subsisted which has allowed to document the wide oscillations of arterial pressure levels during the day. Anyway, the sphygmomanometer with a mercury column has persisted until the present and will still be used for a long time. A new evolving methodology is the continuous ambulatory sphygmomanometry.