American journal of physiology . igation is still in progress. A NEW INSrRUMENT FOR DETERMINING SYSTOLIC ANDDIASTOLIC BLOOD-PRESSURE IN MAN. By JOSEPH ERLANGER. Since the work of Howell and Brush has shown decisively thatinstruments which make use of the principle of Marey—viz., thepressure under which an artery will give its maximum pulsations is the mean pressure in that artery —give, not mean pressures, but mini-mum or diastolic pressures, andsince the same authors have shownthat the systolic and diastolic pres-sure may actually be affected inopposite directions, the importanceof a sphygmom
American journal of physiology . igation is still in progress. A NEW INSrRUMENT FOR DETERMINING SYSTOLIC ANDDIASTOLIC BLOOD-PRESSURE IN MAN. By JOSEPH ERLANGER. Since the work of Howell and Brush has shown decisively thatinstruments which make use of the principle of Marey—viz., thepressure under which an artery will give its maximum pulsations is the mean pressure in that artery —give, not mean pressures, but mini-mum or diastolic pressures, andsince the same authors have shownthat the systolic and diastolic pres-sure may actually be affected inopposite directions, the importanceof a sphygmomanometer that willgive parallel records of the variationsin systolic and diastolic pressuresbecomes evident. Therefore the following instrumenthas been devised. An arm-piecelike that employed in the Hill-Barnard sphygmometer is fastenedabout the arm above the elbow. Its rubber bag (A) communicateswith a mercury manometer (B) and with a Pulitzer bag (C) for vary-ing the pressure. The maximum pressure is obtained by noting the. Proceedings of the American Physiological Society, xxiii pressure required to obliterate the pulse distal to the point of appli-cation of the pressure. With the rest of the apparatus the diastolicpressure is obtained. When the stopcock (D) is open the pressurein the apparatus is also transmitted to the rubber bag (E) enclosedin the glass bulb (F). The air space between these communicateswith the exterior through the stopcock (G) and with the tambour (H)the lever of which writes upon a slowly revolving drum. Thetambour is perforated by a minute opening. To determine theminimum pressure, the stopcock (G) being open, the pressure isquickly raised above the expected minimum. The three-way stop-cock (I) is then closed and the valve (G) is closed. The lever willnow record the pulsations. After, say, twenty pulsations have beenrecorded, the stopcock (I) is turned so as to communicate with thecapillary (K). The pressure falls slowly and is stopped after a fall
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Keywords: ., bookautho, bookcentury1800, bookdecade1890, booksubjectphysiology
