| abstract |
An apparatus is provided which can assist in determining the presence or absence of a venous obstruction such as occurs in hemorrhage or inflammatory conditions affecting the veins by measuring the precentage change in electrical impedance of the veins caused by their temporary forced blockage. This measured change in impedance, normalized with respect to a baseline impedance measured during normal respiration, provides a sensitive index which is indicative of the presence or absence of a clot or constriction. |