Central Blood Pressure: Part 2, Pulse Wave Analysis
We have already dealt with the importance of central blood pressure values and we have seen that pulse wave analysis can provide clear indications of the interpretation of blood pressure values. But how can we measure, noninvasively, central blood pressur
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Central Blood Pressure: Part 2, Pulse Wave Analysis
We have already dealt with the importance of central blood pressure values and we have seen that pulse wave analysis can provide clear indications of the interpretation of blood pressure values. But how can we measure, noninvasively, central blood pressure values and record aortic pressure wave?
5.1
How to Measure Blood Pressure: Work in Progress
Reverend Stephen Hales (1677–1761), an English naturalist, was the first to quantitatively measure blood pressure. Figure 5.1 describes the experiment as it was published. However, he did not continue with his blood pressure experiments for long, as his studies on animal vivisection were greatly criticized. One of his best friends, the poet Alexander Pope, used to say about him: “He is a very good man, only he has his hands imbrued with blood ”. Thus, it was not until a century later that the accurate study of blood pressure was taken up again. At first, invasive methods, such as hemautography, were used (Fig. 5.2). With this test, large-sized animals were stung on a large artery, and the spurt of their blood would trace out a curve on a moving strip of paper. Finally, in the second half of the 19th century, some physiologists, realizing that arterial blood pressure played a large role in cardiovascular diseases, raised the question of noninvasive recording of arterial pressure waveform and assessment of blood pressure values.
5.1.1
Primitive Recordings of Arterial Pulse Wave in Humans
The sphygmograph, developed by Karl von Vierordt (1818–1884) in 1854, was the first noninvasive device used to estimate blood pressure. Von Vierordt’s sphygmometer was a system of levers and weights placed to determine the amount of external pressure needed to stop blood flow in the radial artery (Fig. 5.3). # Springer International Publishing 2017 P. Salvi, Pulse Waves, DOI 10.1007/978-3-319-40501-8_5
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Central Blood Pressure: Part 2, Pulse Wave Analysis
Fig. 5.1 Stephen Hales described his first attempts to measure the values of blood pressure in Volume II of Statical Essays (1733) as follows: “In December I caused a mare to be tied down alive on her back; she was 14 hands high [142 cm], and about 14 years of age, had a fistula on her withers, was neither very lean, nor very lusty: having laid open the left crural artery about 3 inches [7.62 cm] from her belly, I inserted into it a brass pipe whose bore was 1/6 of an inch in diameter [0.42 cm] and to that by means of another brass pipe which was fitly adapted to it, I fixed a glass tube of nearly the same diameter which was 9 feet in length [274 cm]. Then untying the ligature on the artery, the blood rose in the tube to 8 feet in length [244 cm; 244 cm H2O ¼ about 180 mmHg], 3 inches [7.6 cm] perpendicular above the level of the left ventricle of the heart”
However, the result was a bulky and rudimentary device, providing inaccurate measurements. E´tienne Jules Marey (1830–1904) improved von Vierordt’s sphygmograph by making it portable and available in clinical prac
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