The examination of the pulse : including a description of the sphygmograph / by Byrom Bramwell.

  • Bramwell, Byrom, Sir, 1847-1931.
Date:
1881
Catalogue details

Licence: Public Domain Mark

Credit: The examination of the pulse : including a description of the sphygmograph / by Byrom Bramwell. Source: Wellcome Collection.

    10/30 (page 6)
    alteration of the position of the screw D, see fig-. 3) to he brought level with the centre of the strip of smoked paper, as in figs. 1 and 2. The Adjustment of the Pressure.—The pressure of the spring must be altered until the maximum amount of movement of the lever is obtained. Every alteration of the pressure necessitates a correspond¬ ing alteration of the screw D; otherwise the point of the pen is removed from its proper position. The clockwork, which has been previously wound up, is then to be set into motion, and a tracing taken. If the tracing is satisfactory, the name of the patient, the date, and the amount of spring pressure, should be inscribed upon it (by a needle or other fine-pointed instrument). The tracing is then rendered permanent by dipping it in a rapidly drying 1 varnish. Where a comparison of tracings from different arteries (i.e.y the two radials) is required, (1) the greatest care must be taken that all the conditions (the position of the patient, amount of spring pressure, etc.) are the same; (2) the best obtainable tracing from each side must also be compared. In this case it may be necessary to have the pressure on the two sides different, but all the other conditions must be rigidly the same. A comparison of the best attainable tracing is of great importance where there are slight differences in the pulse-waves. In this con¬ nexion it is important to remember that where the heart’s action becomes excited or accelerated as the result of mental or other causes the character of the tracing is materially modified (see figs. 4, 5, 6, and 7). Tracings should always, so far as is possible, be made during tranquil action of the heart. Character of a good Tracing.—The best tracing is that which has the highest up stroke and the most pointed apex. In some patho¬ logical conditions—as, for example, in some aneurisms (see figs. 36 and 37), and in aortic stenosis (see fig. 13)—the apex is rounded ; but this is so extremely rare that a tracing in which the apices are not pointed should always be regarded as imperfect until verified by repeated and careful readjustments of the instrument. The chief points to be attended to in order to obtain a good tracing are—(1) the accurate adjustment of the ivory pad to the centre of the artery; (2) the proper regulation of the pressure. Figures 8 and 9 show tracings from the same pulse with different degrees of pressure. Having described the mode of applying the instrument, the character of the normal and pathological pulse-tracings will now be considered. Analysis of a Sphygmographic Tracing —A tracing consists of a number of curves, each of which represents one beat of the pulse. 1 The varnish recommended by Mahomed is made by macerating an ounce of gnm benzoin in five ounces of rectified spirit, with frequent agitations for two days, and then pouring off the clear liquor from the insoluble constituents of the gum.