Patent ID: 8577462

Claim:
A package in which a medical device is stored, the package comprising an outer shell providing a vapor barrier between an interior space inside the outer shell and an exterior environment; a medical device positioned in the interior space inside the outer shell; the medical device including a liquid-containing element that is subject to drying out as liquid from the liquid-containing element vaporizes and travels from the interior space to the external environment; a condition sensor comprising two metallic elements, each of the two metallic elements being composed of different metals, with each of the different metals selected so that the two metallic elements form an anode and a cathode of an electrochemical cell, each of the two metallic elements being in electrical contact with a conductive water-containing element, so that the water-containing element forms the electrolyte of the electrochemical cell, and an electrically conductive path extending from each of the metallic elements to a location wherein the electrochemical potential formed between the metallic elements can be measured to provide an indication of the degree to which the conductive water-containing element has dried out, wherein the medical device stored in the package further comprises at least one electrode, and wherein the electrode includes a metallic layer in electrical contact with a conductive liquid-containing layer through which electrical current is delivered to a patient when the electrode has been applied to a patient, the conductive liquid-containing layer being subject to drying out as liquid from the liquid-containing layer vaporizes and travels from the interior space to the external environment, and wherein the two metallic elements and water-containing element of the condition sensor are separate from and not shared with the liquid containing element and electrode of the medical device, and wherein the condition sensor provides an indication of whether the liquid-containing element of the medical device has dried out sufficiently that the electrode of the medical device should not be used.