US 4,402,373 AGranted

Blood loss analyzer

OwnerPerry J. Comeauinventor

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Abstract

An apparatus for measuring the true loss of blood from a patient during a surgical operation, comprises a blood container on a weighing means, that provides an output signal equal to the total weight on the weighing means. A weight register is maintained, to be updated periodically to the output of the weighing means. At scheduled periodic times the new weight reading of the weighing means is compared to the previous weight as indicated by the weight register. Any difference, if positive, indicates additional input to the blood container on the weighing means. This positive difference goes to update the weight register, and also to update a blood register indicating total blood loss. If the difference between the new electrical weight signal and the previous (old) electrical weight signal is negative, then an equal number of units is withdrawn from the weight register, to bring it into agreement with the new weight on the weighing means.

Claims14

Dependent claims

Apparatus for determining the total weight of a vaporizable liquid being incrementally placed in a selected container over a selected period of time, comprising;

(a) a first selected container mounted on a weighing means, the output of said weighing means being a continuing electrical signal indicative of the weight of container and contents, at any selected time;
(b) a comparator/subtractor means having a first intermittent input of the new electrical weighing signal (NEWS) from said weighing means;
(c) a weight register (WR) means for continuously outputting an electrical signal equal to the old electrical weighing signal (OEWS), the same being the value of NEWS at the time of the previous intermittent measurement;
the output of said WR being the second input to said comparator/subtractor means;
(d) if said NEWS is greater than said OEWS, the output of said comparator/subtractor will be positive, (indicative of added liquid) and including means responsive to said positive signal to augment the reading of said WR;
and means to augment the total in a liquid register (LR) by the amount of said positive signal;
and
(e) if said NEWS is less than said OEWS, the difference signal will be negative (indicative of a loss of liquid by vaporization), and including means responsive to said negative signal to cause an equal weight to be withdrawn from said WR.

5 more elements

Dependencies are inferred from the claim text.