Patient monitoring systems

Claim 2

A patient monitoring system comprising: a plurality of transducers providing analogue transducer signals representing respectively different parameters of a patient''s condition; respective integrating means each connected with an associated one of said transducers to provide analogue time-loaded integrated signals in response to said transducer signals; respective reference sources providing first and second reference level signals; respective first comparison means connected to each of said integrating means and the respective one of said reference sources to provide a first digital signal in response to said integrated and first reference level signals, indicating the relative levels of the latter signals; respective second comparison means connected to each of said transducers and the respective one of said reference sources to provide a second digital signal in response to said transducer and second reference level signals, indicating the relative level of the latter signals; logic means connected to each of said comparison means to provide an indicator signal in response to each of a plurality of predetermined combinations of said first and second digital signAls; and a patient hazard indicator connected to said logic means, which indicator is operable in response to said indicator signal.

Claim 3

A system according to claim 1 wherein at least one of said integrating means comprises first and second integrators having respectively short and long time constants, each responsive to said transducer signals to provide respectively short term and long term integrated signals; and wherein the respective one of said first comparison means is in two parts, both connected with the respective one of said reference sources, and respectively connected with said first and second integrators, to individually provide said first digital signals.

Claim 4

A system according to claim 2 comprising differencing means connected to said first and second integrators to provide a difference signal in response to said short and long term integrated signals; and wherein said first comparison means comprises a third part connected to said differencing means and the respective one of said reference source to individually provide, in response to said difference and second reference level signals, said first digital signals.

Claim 5

A system according to claim 1 wherein at least one of said reference sources provides fixed value second reference level signals, and comprises third integrating means connected to the respective one of said transducers to provide up-dated first reference level signals in response to said transducer signals.

Claim 6

A system according to claim 1 wherein at least one of said integrating means provides its integrated signal output to represent the exponentially mapped past function of the respective transducer signal.

Claim 7

A patient monitoring system comprising: at least two transducers for providing transducer signals representing respectively different parameters of a patient''s condition; respective integrating means connected with each of said transducers to provide time-loaded integrated signals in response to said transducer signals; a plurality of reference sources for providing individual high reference level signals and individual low reference level signals for each of said integrated signals; respective comparison means connected with each of said integrating means and with said reference sources to compare each of said integrated signals with associated ones of said reference level signals and to provide first digital signals indicating whether said integrated signals are higher or lower than said reference level signals; a plurality of further reference sources for providing further individual high reference level signals and further individual low reference level signals for each of said transducer signals; respective further comparison means connected with each of said transducers and with said further reference sources to compare said transducer signals with associated ones of said further reference signals and to provide second digital signals indicating whether said transducer signals are higher or lower than said further reference level signals; hazard logic means connected to each of said comparison means and said further comparison means to provide a warning signal in response to at least one predetermined combination of said first and second digital signals, and an alarm signal in response to at least one other predetermined combination of said first and second digital signals; fault logic means connected to each of said further comparison means to provide a fault signal in response to at least one predetermined combination of said second digital signals, and respective indicator means connected to said hazard and fault logic means for operation in response to said alarm and fault signals.

Claim 8

A patient monitoring system comprising: at least two transducers for providing transducer signals representing respectively different parameters of a patient''s condition; respective integrating means connected with each of said transducers to provide time-loaded integrated signals in response to said transducer signals; a plurality of reference sources for providing individual high reference level signals and individual low reference level signals for each of said integrated signals; respective comparison means connected with each of said integrating means and with said reference sources to compare each of said integrated signals with associated ones of said reference level signals and to provide first digital signals indicating whether said integrated signals are higher or lower than said reference level signals; a plurality of further reference sources for providing further individual high reference level signals and further individual low reference level signals for each of said transducer signals; respective further comparison means connected with each of said transducers and with said further reference sources to compare said transducer signals with associated ones of said further reference signals and to provide second digital signals indicating whether said transducer signals are higher or lower than said further reference level signals; hazard logic means connected to each of said comparison means and said further comparison means to provide a warning signal in response to at least one predetermined combination of said first and second digital signals, and an alarm signal in response to at least one other predetermined combination of said first and second digital signals; fault logic means connected to each of said further comparison means to provide a fault signal in response to at least one predetermined combination of said second digital signals, and respective indicator means connected to said hazard and fault logic means for operation in response to said alarm and fault signals.

Claim 9

A system according to claim 6 wherein each of said integrating means comprises both relatively short and long time constant integrating means connected with the respective one of said transducers to provide individual integrated signals.