Process and apparatus for patient danger recognition and forecasting of a danger condition, especially in case of intensive medical care

• US 4,197,854 A
• Filed: 01/24/1978
• Issued: 04/15/1980
• Est. Priority Date: 07/19/1974
• Status: Expired due to Term

• Current Assignee: Medicor Muvek
• Original Assignee: Medicor Muvek
• Inventors: Kasa, Zoltan
• Primary Examiner(s): Kamm, William E.
• Application Number:
  US05/871,924
• Time in Patent Office: 812 Days
• Field of Search: 128/2 R, 128/2.05 R, 128/2.05 T, 128/2.06 A, 128/2.06 R, 128/2.06 F, 340/279, 235/92 PD, 235/92 SH
• US Class Current: 600/301
• CPC Class Codes: A61B 5/0205 Simultaneously evaluating both cardiovascular conditions and different types of body conditions, e.g. heart and respiratory condition
• CPC Class Codes: A61B 5/033 Uterine pressure

Abstract

Process and apparatus for patient danger recognition and forecasting, particularly for the intensive medical care of the patient. The invention uses various variables to set up a danger function that represents the probability of occurrence of a danger condition, forms average values of the danger function throughout subsequent time periods that are shorter than the time required for a medical intervention, by comparing the formed average values with levels of increasing sequences of threshold values, providing an indication associated with the highest exceeded threshold value, using the average values to set up a regression function which approximates the sequence thereof, determining a subsequent extrapolated value of the function for the next time period that represents a forecast average value of the danger function, and indicating the extrapolated value provided it is higher than a predetermined level. Preferably three threshold values are used in the comparing step, with magnitudes of 40, 60 and 80% of the danger function, respectively.

Claims

1. A process for the recognition and forecasting of a possible danger condition, especially for intensive medical care where an endangered patient is under continuous instrumental and personal attendance, which danger conditions is a complex function of several variables that are continuously measured specific conditional characteristics, data reported occasionally by the attending personnel, data obtained from the anamnesis, and data representing time durations that have elapsed since the occurrence of certain events, the process comprising the steps of:

using the variables to set up a danger function that represents the probability of occurrence of the danger condition;

forming discrete average values of the danger function throughout subsequent predetermined discrete time periods that are substantially shorter than the average time required for a medical intervention, known to be between 2 and 10 minutes, to overcome the danger condition;

comparing the formed average values with respective levels of discrete increasing predetermined sequences of threshold values;

providing an indication associated with a highest momentaneous exceeded threshold value;

using the discrete average values to set up a regression function which approximates the sequence thereof;

determining a subsequent extrapolated value of the regression function for the next time period that represents a forecast average value of the danger function; and

also indicating the extrapolated value provided it is higher than a predetermined level which latter corresponds to at least the lowest one of the threshold values;

which lowest value has not been exceeded during said comparing step.

2. The process as defined in claim 1 further comprising the repetition of, wherein said comparing step with three of the threshold values, the magnitudes of which correspond in succession to 40, 60 and 80% values of the danger function, respectively.

3. An apparatus for the recognition and forecasting of a possible danger condition, especially for intensive medical care, where an endangered patient is under continuous instrumental and personal attendance, comprising, in combination:

an operating unit (8) located in the vicinity of the patient, to receive results of observances, adjusted by the attending personnel, and from instruments that measure specific conditional characteristics related to the occurrence of the danger condition;

a danger function generator (2) having inputs (9) for receiving output signals of said instruments and for providing a danger function (F/D/) at its output that represents the probability of occurrence of the danger condition;

an averaging unit (3) having an input connected to said generator output, for averaging the danger function throughout subsequent predetermined discrete time periods;

digital comparator means (74 to

     76) connected to an output (80) of said averaging unit, for comparing the average values with at least one predetermined threshold value in each time period;

an indicating unit (7, 45,

     70) connected to signal outputs (82,

     83) of said comparator means, for giving indications of degrees of the danger condition, depending on said comparator outputs;

a forecasting unit (4) also connected to said averaging output, including a shift memory (40 to

     43) having at least two memory elements for storing a number of the subsequent average values obtained during the preceding predetermined time periods;

said forecasting unit serving to establish a regression function which approximates the sequence of the stored average values and to forecast by an indication via an additional element (45) of said indicating unit, by way of D/A conversion, analog addition and comparison in elements (46, 48,

     47) of said forecasting unit, a subsequent extrapolated value of the regression function for the next time period; and

a control unit (5) for determining the time periods, being connected to said averaging unit and said forecasting unit.

4. The apparatus as defined in claim 3, further comprising a time-measuring unit (6) for delivering a signal that is proportional to the time duration that has elapsed since the beginning of an event adjusted by the attendant personnel, said operating unit (8) being operatively connected with said measuring unit, the output of which latter is connected to one of said input unit (1) and said danger function generator (2).

5. The apparatus as defined in claim 3, further comprising in said averaging unit (3) an A/D converter (21) and a numerical integrator (22) for summarizing discrete values of the danger function, sampled by clock pulses having a considerably shorter cycle time than the predetermined time periods, said danger function generator (2) being connected to said averaging unit through said converter, and wherein said control unit (5) has an output (52) for delivering the clock pulses, being connected to a clock-signal input of said integrator.

6. The apparatus as defined in claim 5, wherein said comparator means (74 to 76) has inputs (81) that are parallel-connected and controlled by way of said averaging output (80), from an output (34) of said integrator (22), by the integrated value of the danger function, said comparator means having at least two units (74 to 76) therein with separate reference inputs, with means (77 to 79) connected to said comparator units for adjusting the differring threshold values that correspond to successive and increasing ones of the discrete values of the danger function, said comparator signal outputs (82, 83) being led to elements (71 to 73) of said indicating unit (7, 45, 70), each associated with a predetermined danger level, wherein an inverse output (82) of one (74) of said comparator units, being associated with the lowest danger level, is a further element (70) of said indicating unit for dinstinctively signalling a danger-free condition.

7. The apparatus as defined in claim 6, wherein said adjusting means (77 to 79) serves to provide threshold values of 40, 60, 80% values of the danger function, respectively, for three of said comparator units (74 to 76).

8. The apparatus as defined in claim 6, wherein said comparator means has three units (74 to 76) therein, respectively connected to said indicating elements (71 to 73), and electronic selecting means as an effect of which only that one of said elements operates that belongs to the highest exceeded threshold value.

9. The apparatus as defined in claim 6, further comprising in said forecasting unit (4) D/A converters (30 to 33), analog-level adjusting means (a₁ to a₄) for adjusting coefficients of the regression function, and an analog adder (48) which furnishes an extrapolated average value of the danger function that corresponds to the next time period, wherein an input of one (40) of said shift-memory elements (40 to 43) is connected to said integrator output (34), and individual outputs (35 to 38) of said memory elements are coupled through respective ones of said converters to said adjusting means, outputs of the latter means being connected to respective inputs of said adder.

10. The apparatus as defined in claim 9, further comprising a digital OR circuit (80) at said averaging output, said circuit having a first input connected to said integrator output (34), a second input connected to an output (35) of said one (40) shift-memory element, and outputs of said circuit constituting said comparator inputs (81).

11. The apparatus as defined in claim 9, further comprising in said forecasting unit (4) an analog comparator (47) having a reference input and a D/A converter (46), wherein an output of said analog adder (48) is connected to a signal input of said comparator, said input of the latter being coupled to an output of said converter, the latter having inputs connected to said inverse output (82) and to a signal output (83) of said one (74) comparator unit, as well as to a signal output of another one (75) of said comparator units (74 to 76), respectively, and an output of said analog comparator is coupled to said additional element (45) of the indicating unit (7, 45, 70), for producing a distinctive indication of a forecast danger condition.