. Physical diagnosis . y given time with that in themanometer. 1. Measurement of Systolic or Maximum Pressure. To use the instrument for measuring systolic blood pressure wepump in air until the radial pulse stops, and at that instant note theheight of the mercury column. The reading thus obtained is takento represent the systolic or maximum pressure in the brachial raise the mercury column slightly above the point at which thepulse stops, then let the column slowly fall and note the point on thescale at which we feel the return of the pulse is easier and no less accuratethan to fix
. Physical diagnosis . y given time with that in themanometer. 1. Measurement of Systolic or Maximum Pressure. To use the instrument for measuring systolic blood pressure wepump in air until the radial pulse stops, and at that instant note theheight of the mercury column. The reading thus obtained is takento represent the systolic or maximum pressure in the brachial raise the mercury column slightly above the point at which thepulse stops, then let the column slowly fall and note the point on thescale at which we feel the return of the pulse is easier and no less accuratethan to fix the point at which the pulse first disappears. PALPATION AND THE STUDY OF THE PULSE 109 It is true that the air within the rubber armlet has to overcomenot only the pressure within the radial artery, but the resistance ofthe artery wall and the elasticity of the soft parts around it. Theformer factor has been shown to represent a pressure of, not morethan 2 or 3 mm. Hg, provided the artery walls are normal. If arterio-. Fig. 93.:—Faughts Type of Riva Rocci Sphygmomanometer. sclerosis is present, it has been estimated by Herringham that theartery may oppose a resistance of 15 to 20 mm. Hg. The more care-fully conducted experiments of Janeway, however, convince me thatHerringham is wrong and that sclerosed arteries offer a direct resist-ance of less than 5 mm. Hg. The amount of error thus introducedis not of importance. 110 PHYSICAL DIAGNOSIS The resistance of the soft parts around the artery is a factor of noimportance, provided the compressing armlet is at least 12 cm. huge arm gives no higher reading than a shrivelled one, as has beenshown by Janeway in a patient one of whose arms was congenitallyatrophied while the other was enormous. The instrument is a very simple and quick one to use, needingvery little practice and not more than a minute or a minute and ahalf for a single reading. The chief objection to it is its bulk andfragility. Systolic pressure may also be m
Size: 1503px × 1662px
Photo credit: © Reading Room 2020 / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookdecade1910, booksubjectdiagnos, bookyear1912
