GB1336880A - Sphygmomanometer alarm reset technique - Google Patents

Abstract

1336880 Electro-medical apparatus F HOFFMANN-LA ROCHE & CO A G 30 Dec 1970 [12 Jan 1970] 61704/70 Heading G1N [Also in Division A5] An alarm system is a sphygmomanometer for continuously monitoring blood pressures whose values do not fall within a predetermined acceptable range bounded by maximum and minimum values, comprises at least one reset circuit to reset an alarm activated in response to an alarm condition without inhibiting subsequent alarm activation with the occurrence of an alarm condition when the alarm is reset. Manometer tubes 12 indicate the pressure level around a limb, whilst range indicator 19 displays the maximum and minimum acceptable blood pressures 21 and 22 respectively. Output signals of systolic pressure from manometer 12 are fed into high and low alarm comparators 25 and 26, into which signals corresponding to the high and low preset levels 21 and 22 are also fed. Signals from the comparators 25 and 26 are fed into an alarm logic unit 29 together with signals from a control unit 28 attached to a transducer 15 at the blood vessel. The logic of the operation of the alarm system 29 is shown in Fig.2 in which a high level alarm 17 is activated by signals from the control unit 28 and the high alarm comparator 25, which is excited when the blood pressure 12 is higher than the acceptable maximum. These signals enter an AND gate 32 which then provides an input signal for a second AND gate 37. Further signals enter AND gate 37 from a start button 36, and from a flip flop circuit 34 which is activated by the start button and produce an output signal from the AND gate which activates the alarm 17. The alarm is deactivated by pressing reset button 39 when alarm conditions do not exist and there is no input to the AND gates 32 and 37. If, however alarm conditions continue to exist and the reset button 39 is pressed then a further AND gate 33 is actuated and flip flop 34 is reset, cutting off the output to AND gate 37, flip flop 38 is simultaneously reset cutting out the alarm by the reset button. The low pressure alarm 18 is actuated and reset in a similar manner by AND gates 43, 44, 48 and flip flops 45 and 49.