| 摘要 |
<p>494,815. Blood-pressure measuring- apparatus. SIEMENS & HALSKE AKT.- GES. March 4, 1938, No. 6875. Convention date, March 12, 1937. [Class 81 (ii)] In apparatus for continuously measuring blood-pressure in which compressed air is fed to an inflatable sleeve through a pipe which also communicates with a closed chamber, there is provided in the chamber a bolometer arrangement which is influenced by the air pulses set up by the pulse beat, and regulates through an amplifier the supply of air. A sleeve comprising two cushions o, u, secured about the upper arm of the patient, is inflated by air from a pressure vessel 2 through valves 3, 5, 6 and an electromagnetically-controlled valve 4. Quick-filling and quick-discharge valves 11, 12 are also provided. The sleeve communicates through slot-nozzle 8 with a chamber 9 containing a bolometer bridge 15, 16, 17, 18 which is fed from transformer 20. For the measurement of the systolic blood pressure, the pressure within the sleeve, which is first greater than the systolic pressure, gradually drops due to escape of air from chamber 9 through valve 7 and relief valve 10, until at about the systolic blood pressure, a pulse beat causes a jet of air to be ejected through slot 8 on to the branches 15, 16 of the bolometer bridge which are thereby cooled. The potential disturbance in the bolometer bridge is amplified in amplifier 21 and causes the electromagnetically-operated valve 4 to open. This is kept open by a retarding arrangement in the amplifier until the bolometer reaches its equilibrium state, whereupon the cycle is repeated. The pressure fluctuations are indicated by manometer 14 and recorded by pressure recorder 13, the systolic blood pressure being shown by the lower peaks of the curve. An oscillograph 24 may be connected to the output terminals of the bolometer bridge through amplifier 23. For measurement of the diastolic blood pressure, the valve 4 is normally open, the pressure gradually increasing until a pulse beat causes a sufficiently large air impulse to operate the bolometer thereby causing the valve 4 to close. The valve remains closed for a predetermined period during which the pressure drops, due to the escape of air through valve 10, below the value at which the apparatus is sensitive to pulse beats. The valve 4 then opens again and the cycle is repeated. The upper peaks of the curve correspond to the diastolic blood pressure.</p> |
