U.S. Pat. No. 4,863,016, entitled "Packaging for a Sterilizable Calibratable Medical Device", assigned to the assignee of the present invention, describes a package for and method of packaging a sterilizable calibratable medical device that includes a hydratable sensor component. Because the specification of the above noted patent, including the Background of the Invention, is useful to an understanding of the present invention, the specification of U.S. Pat. No. 4,863,016 is hereby incorporated herein by reference.
The medical device referenced in the above noted patent is a blood chemistry sensor that must be maintained in a sterile environment during storage and in a clean environment during the calibration procedure. The packaging provided for the medical device accommodates these requirements. This packaging includes a manifold and a hydration solution pouch, each connected to the sensor component by plumbing. The plumbing also connects the sensor component to the ambient environment of the plumbing. When the packaging is manufactured, the manifold, plumbing, and medical device are sealed in a wrap including a gas-permeable, bacterial retentive surface. The wrap and its contents, including the exterior surfaces of the components, are sterilized by exposure to gaseous ethylene oxide (ETO). During the sterilization procedure, the plumbing is adjusted so that the sensor is exposed to the ambient environment, i.e., the sterilizing gas. After sterilization, the plumbing is adjusted and the medical device is hydrated within the package by directing the hydration solution from the hydration solution pouch to the sensor by means of the plumbing. To allow storage of the package for an extended period of time, a gas-impermeable bag is provided to define a chamber in which the ambient sterile environment of the plumbing is preserved, while the sensor component remains immersed in the hydration solution.
Prior to using the medical device, the sensor component must be calibrated. A portion of the plumbing remote from the sensor component is removed from the packaging. A reservoir including a calibration solution is connected to the plumbing, and the calibration solution is conveyed to the sensor component. As the calibration solution is introduced to the sensor component, the hydration solution is flushed into the manifold via the plumbing. In this manner, the sensor component is calibrated without removing it from the clean environment of the packaging.
The above description reveals one of the problems with the packaging used for the medical device. Before the sensor component can be calibrated, the hydration solution in which it is stored must be removed from the packaging and replaced with the calibration solution. This process introduces several undesirable complications. It would therefore be desirable to calibrate the sensor component without removing it from the clean environment of the package and without removing the hydration solution. The present invention contributes to attaining this objective.