GB1394906A - Cardiovascular test station pressurometer interface system - Google Patents

Abstract

1394906 Measuring blood pressure electrically SEARLE MEDIDATA INC 15 June 1972 [18 June 1971] 28068/72 Heading A5K [Also in Division G1] A pressurometer measuring a patient's bloodpressure provides a plurality of electrical outputs corresponding to different pressure levels, with an output marked if, during deflation of a blood-inhibiting #uff, Korotkoff sounds have been detected at that level, thereby providing a band of marked outputs whose upper and lower levels are the systolic and diastolic blood pressures. The invention provides an interface unit between the pressurometer and a computer computing actual blood pressures to sequentially sample the outputs and at a transition from an unmarked to a marked output and from a marked to an unmarked ouput, generates a serial address signal for each transition to represent the systolic and diastolic pressures. In Figure 2 the parallel signals from the pressurometer 18 derived during the deflation cycle of the pressurometer are normalised in circuit 40 and connected in groups to a multiplexer 46 under the control of a counter 68 driven by clock signals from a counter 36 the multiplexers 46 and a second multiplexer 58 sample each pressure output signal in turn. Sample and hold circuit 60 holds a previous sample for comparison in exclusive OR gate 62 with the current sample and upon a transition, opens gate 66 to read out a corresponding address signal from address multiplexer 72 supplied with addresses from counter 70 and Which are sent over a data link 34 to the computer console 36. During the exhaust cycle of the cuff, gate 82 passes electrical signals derived from Korotkoff sounds to pulse shaper 82 and the resulting pulses are clocked to the console via gate 64, from which the computer 74 calculates the patient's pulse rate. At the end of a deflation of the cuff an exhaust signal 80 zero's the counters 68 and 70 to begin the sampling cycle described above.