Bioelectric apparatus for monitoring body fluid compartments

Apparatus for measuring body water compartmentalization of a human subject, having potassium ion and sodium ion concentrations which can be used to form a sum, comprising:

• signal generating means for generating a sequence of alternating current electrical signals having a predetermined constant current, each signal of the sequence having a different predetermined frequency;
• means for applying the sequence of signals across a first predetermined pair of locations on the subject;
• measuring means coupled to the subject for determining body resistance between a second pair of locations disposed between the first pair of locations on the subject, and for generating a resistance signal and measuring means for determining a phase angle between the applied alternating current signals and voltage signals measured at the second pair of locations and generating a phase shift signal;
• data generation means for generating and storing anthropometric and electrolyte concentration data related to the subject;
• processor means coupled to the measuring means for processing the body resistance and phase angle data, and coupled to the data generation means for processing the anthropometric and electrolyte concentration data to compute extracellular, intracellular and total water volumes of the subject in accordance with predetermined relationships having a form V.sub.e =b.sub.0 +b.sub.1 [H.sup.2 /(R.sub.e M)], V.sub.i =b.sub.0 +b.sub.1 (C.sub.i H.sup.2)/M+b.sub.2 H.sup.2 /(R.sub.i M), and V.sub.t =b.sub.0 +b.sub.1 [H.sup.2 /(R.sub.e M)]+b.sub.2 (C.sub.i H.sup.2)/M+b.sub.3 H.sup.2 /(R.sub.i M) for intracellular, extracellular and total body water volumes, respectively, and where H is the subject's height. M is the sum of the concentration of the subject's sodium and potassium ions, and b.sub.0, b.sub.1, b.sub.2, and b.sub.3 are predetermined multrivariate linear regression coefficients;
• and
• display means coupled to the processor means for displaying the computed intracellular, extracellular and total water volumes of the subject.

Apparatus for measuring the body water compartmentalization of a human subject, comprising:

• signal generating means for generating a sequence of alternating current, constant current electrical signals at a predetermined number of different frequencies;
• means for applying the sequence of constant current electrical signals across a first predetermined pair of points on the subject;
• means for sensing the sequence of alternating current, constant current electrical signals applied to the subject;
• means for sensing an electrical current at a second predetermined pair of points on the subject, which sensed current is proportional to resistance between the second pair of points;
• means for measuring and electronically storing anthropometric and electrolyte concentration data of the subject;
• and
• processor means for processing sensed constant current and sensed electrical signals derived from the first and second pairs of electrodes and the anthropometric and electrolyte concentration data in accordance with predetermined relationships having a form V.sub.e =b.sub.0 +b.sub.1 [H.sup.2 /(R.sub.e M)], V.sub.i =b.sub.0 +b.sub.1 (C.sub.i H.sup.2)/M+b.sub.2 H.sup.2 /(R.sub.i M), and V.sub.t =b.sub.0 +b.sub.1 [H.sup.2 /R.sub.e M)]+b.sub.2 (C.sub.i H.sup.2)/M+b.sub.3 H.sup.2 /(R.sub.i M) for entracellular, extracellular and total body water volumes, respectively, and where H is the subject's height. M is the sum of the concentration of the subject's sodium and potassium ions, and b.sub.0, b.sub.1, b.sub.2 and b.sub.3 are predetermined multivariate linear regression coefficients to compute intracellular, extracellular and total water volumes of the subject as a function thereof.

Apparatus for determining body water compartmentalization of a human subject utilizing anthropometric data of the subject, said apparatus comprising:

• signal generating means for selectively generating a plurality of alternating constant current signals that each have a different predetermined frequency;
• first and second electrodes disposed on the subject and adapted to couple the alternating constant current signals to the subject;
• third and fourth electrodes disposed on the subject at selected locations between the first and second electrodes and comprising means for coupling the alternating constant current signals applied to the subject;
• processing means coupled to the second, third, and fourth electrodes and electrical ground, for processing the signals coupled thereby including means for generating a first amplitude signal indicative of the amplitude of the signal sensed between the second and third electrodes, and means for generating a second amplitude signal indicative of the amplitude of the signal sensed between the fourth electrode and electrical ground, and means for generation a phase signal indicative of a phase difference between the first and second amplitude signals;
• and
• microprocessor means for containing stored anthropometric data relating to the subject coupled to the processing means, for processing the first and second amplitude signals, the phase signals, and the anthropometric data to compute body water compartmentalization of the subject in accordance with predetermined relationships having a form V.sub.e =b.sub.0 +b.sub.1 [H.sup.2 /(R.sub.e M)], V.sub.i =b.sub.0 +b.sub.1 (C.sub.i H.sup.2)/M-H.sup.2 /(R.sub.i M), and V.sub.t =b.sub.0 +b.sub.1 [(H.sup.2 /R.sub.e M)]+b.sub.3 (C.sub.i H.sup.2)/M+b.sub.3 H.sup.2 /(R.sub.i M) for intracellular, extracellular and total body water volumes, respectively, and where H is the subject's height, M is the sum of the concentration of the subject's sodium and potassium ions and b.sub.0, b.sub.1, b.sub.2, and b.sub.3 are predetermined multivariate linear regression coefficients.

A method of determining the body water compartmentalization of a human subject utilizing anthropometric data of the subject, said method comprising the steps of:

• generating alternating constant current signals at a plurality of different predetermined frequencies;
• coupling the alternating constant current signals to a first plurality of locations on the subject;
• sensing the alternating constant current signals applied to the subject;
• sensing the phase angle between constant current signals and signals derived at a second plurality of locations on the subject located between the first plurality of locations;
• processing the sensed signals to generate a first amplitude signal indicative of an amplitude of a signal sensed between a first plurality of locations, and to generate a second amplitude signal indicative of an amplitude of a signal sensed between the second pluarlity of locations, and to generate a phase signal indicative of a phase difference between the first and second amplitude signals;
• and
• processing the first and second amplitude signals, the phase signals, and the anthropometric data of the subject to compute body water compartmentalization of the subject in accordance with predetermined relationships having a form V.sub.e =b.sub.0 +b.sub.1 [H.sup.2 /(R.sub.e M)], V.sub.i =b.sub.0 +b.sub.1 (C.sub.i H.sup.2)/M+b.sub.2 H.sup.2 /(R.sub.i M), and V.sub.t =b.sub.0 +b.sub.1 [H.sup.2 /(R.sub.e M)]+b.sub.2 (C.sub.i H.sup.2)/M+b.sub.3 H.sup.2 /(R.sub.i M) for intracellular, extracellular and total body water volumes, respectively, and where H is the subject's height, M is the sum of the concentration of the subject's sodium and potassium ions, and b.sub.0, b.sub.1, b.sub.2, and b.sub.3 are predetermined multivariate linear regression coefficients, and b.sub.0, b.sub.1, b.sub.2, and b.sub.3 are predetermined multivariate linear regression coefficients to compute intracellular, extracellular and total water volumes of the subject as a function thereof.

A method of determining body water compartmentalization of a subject, said method comprising the steps of:

• generating alternating constant current signals at a plurality of different predetermined frequencies;
• coupling the alternating constant current signals to a plurality of locations on the subject;
• sensing the alternating constant current signals applied to the subject at a second plurality of selected locations;
• processing selected ones of the sensed signals to generate a first amplitude signal indicative of an amplitude of a signal sensed between a first set of locations, and to generate a second amplitude signal indicative of an amplitude of a signal sensed between a second set of locations, and to generate a phase signal indicative of a phase difference between the first and second amplitude signals;
• processing the first and second amplitude signals, the phase signals, and anthropometric data of the subject to compute a body impedance of the subject as a function of frequency;
• and
• processing the first and second amplitude signals, the phase signals, and the anthropometric data related the subject to compute the body water compartmentalization of the subject in accordance with predetermined relationships having a form V.sub.e =b.sub.0 +b.sub.1 [H.sup.2 /(R.sub.e M)], V.sub.i =b.sub.0 +b.sub.1 (C.sub.i H.sup.2)/M+b.sub.2 H.sup.2 /(R.sub.i M), and V.sub.t =b.sub.0 +b.sub.1 [H.sup.2 /(R.sub.e M)]+b.sub.2 (C.sub.i H.sup.2)/M+b.sub.3 H.sup.2 /(R.sub.i M) for intracellular, extracellular and total body water volumes, respectively, and where H is the subject's height, M is the sum of the concentration of the subject's sodium and potassium ions, and b.sub.0, b.sub.1, b.sub.2, and b.sub.3 are predetermined multivariate linear regression coefficients to compute intracellular, extracellular and total water volumes of the subject as a function thereof.