An interface to display special physiologic signals on patient monitors.
OBJECTIVE
The objective of this study was to develop an interface to allow special physiologic signals (e.g., in a research setting) to be displayed on the invasive pressure channel of conventional clinical monitors. The interface accepts single-ended high-level signals for display using the pressure channel of patient monitors, which use strain-gauge transducers employing direct current (DC) excitation.


METHODS
By studying the electronic circuitry common to most clinical invasive pressure measurement systems (Wheatstone bridge, differential input instrumentation amplifier) it was possible to develop an interface to convert high-level single-ended signals into the low-level differential signal needed for input to an invasive pressure channel.


CONCLUSIONS
The device is useful when it is desired to display signals from special transducers on regular patient monitors. Schematic diagrams and sample results are provided.
Department of Anaesthesia, Toronto Hospital, Ontario, Canada.
D J
DJ
Doyle
D006801:Humans; D008991:Monitoring, Physiologic / Q000295:instrumentation*; D014160:Transducers, Pressure