A new sphygmomanometer / by G. A. Gibson.

Date:
1909
Catalogue details

Licence: In copyright

Credit: A new sphygmomanometer / by G. A. Gibson. Source: Wellcome Collection.

Provider: This material has been provided by the Royal College of Physicians of Edinburgh. The original may be consulted at the Royal College of Physicians of Edinburgh.

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    Sometimes, as was indeed noticed by von Reckling- J| hausen (29), Janeway (4), and Masing (30), in taking 11 tracings either with the sphygmograph or plethysmograph ||! along with the Riva Rocci sphygmomanometer, one or ||j two little waves show themselves before the appearance Iji of definite pulsation. In most cases, however, the return |ji of the pulsation is quite unmistakable. The usual appear-'|j ances are shown in Fig. 3, taken with slow revolution of |j the cylinder, and in Fig. 4 with quick movement. || In the interpretation of the tracings there is one point iJ which may always be depended upon with a reasonable Ij degree of certainty: the point at which the pulsation Ij returns in the vessel below the seat of compression is ijl approximately the systolic pressure. This has been Ijl admitted ever since the observations of Vierordt (ii) ^nd |j| von Basch (14). The middle point of the kymographic'Ijl curve at this point is therefore chosen as the index ofil systolic pressure. It is perfectly true that it is not j| absolutely the end pressure. The top of the first wave jj which appears gives the maximum systolic pressure indeed, |j but it is the lateral, and not the end pressure which is jj recorded, and therefore the method of circular compression, I as was shown by Masing (30), is not the absolute maximum ; j the difference, however, between the lateral and terminal] pressures in one of the larger arteries is inconsiderable. j The determination of the diastolic pressure is not such] an easy problem. Marey (12) originally suggested that! the point at which the largest swing of the instrument occurred was an index of the mean pressure, and this was adopted and amplified by Roy and Adami (31). It has! been proved, however, by Howell and Brush (27) that this! does not indicate the mean, but the diastolic pressure i Masing (30), who obtained some tracings from the arteiy: below the seat of compression, believes that the greates' diastolic pressure. This must, however, be an error, a; the greatest amplitude of oscillation of the sphygmographi' movement of the sphygmographic tracing marks tht I h . \
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