An address on blood pressure in man : its estimation and indications for treatment : delivered before the Westminster Division of the British Medical Association / by Sir Lauder Brunton.

  • Brunton, Thomas Lauder, Sir, 1844-1916.
Date:
1909
Catalogue details

Licence: In copyright

Credit: An address on blood pressure in man : its estimation and indications for treatment : delivered before the Westminster Division of the British Medical Association / by Sir Lauder Brunton. Source: Wellcome Collection.

Provider: This material has been provided by The Royal College of Surgeons of England. The original may be consulted at The Royal College of Surgeons of England.

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    mercury stands in the manometer is then noted. This gives the tension at which the blood within the vessel can overcome external pressure. The objections to this instrument are the trouble it takes to empty the finger of blood and the difficulty there sometimes is of being quite sure of the moment when the blood returns to it. In another subdivision of band apparatus the pressure is applied to the forearm or arm by an india-rubber bag encircled by a broad unyielding band. The air is blown into this until the pulse at the wrist can no longer be distinguished, and the pressure is then read off either from a mercurial or aneroid manometer, which is also con- nected with the bulb by which air is pumped into the armlet. Two of the most convenient forms of this apparatus are Martin’s and Lockhart Mummery’s. In Martin’s the manometer is formed by a U tube containing mercury ; in Lockhart Mummery’s by a somewhat wide cistern from which a graduated tube rises. In Martin’s the mercury descends in one leg of the tube as it rises in the other, and the actual height of the mercurial column depends on its rise above the zero point in the ascending column plus its fall below the zero point in the descending one. If both tubes are of equal calibre the height of the column will be exactly given by doubling the rise above the zero point; but if the two tubes are of unequal size, doubling the rise above zero may give a very inaccurate reading indeed, and each manometer ought to have a scale made expressly for itself. We can see the effect of inequality between the size of the two limbs in Lockhart Mummery’s, where the cistern which constitutes the descending limb is so wide that the fall in it is almost negligible, and if we were to double the rise above zero in the ascending limb as we did in Martin’s we would get very nearly twice the true measure. The disadvantage of the band apparatus is that, although it may be used above the dress, yet it is better to have the arm exposed, and this is troublesome. It also causes discomfort in the hand and arm, and sometimes even pain, which makes nervous and sensitive ladies dislike it. The advantage is that it is less liable to give a wrong reading through imperfect application, and its indications are therefore generally much more trustworthy than those obtained by simple pressure bulbs. Instead of a mercurial manometer the pressure may be estimated by a column of coloured liquid working against the compressed air, as in Oliver’s apparatus, or by an aneroid. The latter, I find, is the most convenient form. The band apparati s is often known by the name of the Riva-Rocci, as he first introduced the method, although it has been considerably modified by others—Hill arid Barnard, Martin, Mummery, and many others. Its indi- cations are upon the whole, as I have said, more trust- worthy than those of von Basch’s, but the latter apparatus is so easy to use that if we employ half a minute to count the pulse we can ascertain the tension easily in half a minute more without any trouble to the patient. W e