Patent ID: 7354417

Claim:
A method for determining the volume of fluid in the peritoneal cavity of a subject comprising: (a) placing measuring electrodes M LL and M RL on the loins of the subject, M LL being placed on the left loin and M RL being placed on the right loin, M LL and M RL defining a loin plane; (b) placing measuring electrodes M LB and M RB on the buttocks of the subject, M LB being placed on the left buttock and M RB being placed on the right buttock, M LB and M RB defining a buttock plane; (c) placing upper current-providing electrodes I LU and I RU on the subject, I LU being outboard of measuring electrode M LL and I RU being outboard of measuring electrode M RL ; (d) placing lower current-providing electrodes I RL and I LL on the subject, I RL being outboard of measuring electrode M RB and I LL being outboard of measuring electrode M LB ; (e) connecting upper current-providing electrode I LU to upper current-providing electrode I RU ; (f) connecting lower current-providing electrode I LL to lower current-providing electrode I RL ; (g) applying current I between the connected upper current-providing electrodes and the connected lower current-providing electrodes; (h) measuring the voltage Î¦ L between M LL and M LB while current I is applied; (i) measuring the voltage Î¦ R between M RL and M RB while current I is applied; and (j) determining the volume V of fluid in the peritoneal cavity based on the equation: V =( K P /Ïƒ)Â·( L P 2 /R ) where: (1) K P is a subject-specific calibration constant; (2) Ïƒ is the conductivity of the fluid in the peritoneal cavity; (3) L P is the distance between the loin plane and the buttock plane; and (4) R is the average of R L and R R , where R L =Î¦ L /I, and R R =Î¦ R /I.