GB1484332A - Electrical apparatus responding to the condition of a patient - Google Patents

Abstract

1484332 Detecting abnormal conditions of a patient in bed WILLIAM BEAUMONT HOSPITAL 25 Oct 1974 46336/74 Heading G1N [Also in Divisions G4 and H3] A condition responsive circuit to respond to normal and abnormal conditions of a patient in bed comprises a switch, 12, which on opening turns on an FET 10 by its gate after a time delay during which the condition of the gate is sustained, as by a capacitor 32, and an output means is coupled to one at least of the source and drain electrodes of the FET to generate an output when the FET is turned ON. The switch is preferably opened when a patient gets out of bed, although it may be of a type actuated by the presence or absence of moisture in the bed or in a feeding tube. The FET turns on a transistor 20 to actuate signal means to provide an alarm. The signal means may be a uni-junction oscillator driving a loudspeaker, Fig. 3 (not shown), or a uni-junction oscillator frequency modulating an RF oscillator for remote detection, Fig. 4 (not shown), or a lamp. Instead of a transistor 20 an SCR (34) Fig. 2 (not shown), may be used to provide a latching effect with a reset button (36) provided. A test button 28, Fig. 1, may be provided. Preferably two separate batteries are used. It is suggested that the moisture sensitive switch could be used to indicate the absence of fluid in an intravenous feeding tube.