Patent ID: 7678057

Claim:
A non-invasive device that identifies volume insufficiency in a patient, comprising: a. a transducer that records a pulse density signal from said patient during at least one respiratory cycle prior to administration of a cardiovascular volume load and during at least one respiratory cycle following administration of said cardiovascular volume load, wherein each respiratory cycle includes a plurality of cardiovascular subcycles; b. a controller that controls said transducer to initiate said record of said pulse density signal, said controller comprising at least one of the following: i. a manual or an automated switch; ii. a plurality of software rules; or iii. a combination thereof; c. an activator that activates said cardiovascular volume load; and d. a processor that is configured to filter said pulse density signal to capture a maximum and minimum data point in each cardiovascular subcycle and to calculate a percent deviation of said pulse density signal across all of said cycles, said percent deviation reflecting a volume status of said patient, said percent deviation being calculated according to the following formula: percent deviation data signal =( P mean max −P mean min )/[( P mean max +Pmean min )/2]×100, wherein percent deviation data signal is a variation in said pulse density signal recorded by said transducer prior to said cardiovascular volume load and following said cardiovascular volume load, wherein Pmean max is a maximum mean value of said pulse density signal recorded during all of said cycles, wherein Pmean min is a minimum mean value of said pulse density signal recorded during all of said cycles, wherein each said mean value of said pulse density signal is calculated for each said cardiovascular subcycle (c), as follows: Pmean c =Pmax c +Pmin c /2, wherein Pmax c is a maximum pulse density signal in a given subcycle (c) and Pmin c is a minimum pulse density signal in said given subcycle (c).