Barometric pressure sensor for use with implantable absolute pressure

Abstract

A barometric pressure sensor for deriving reference pressure data for use in combination with absolute pressure data derived by an implantable medical device (IMD) is disclosed. The barometric pressure sensor is located in a sensing module adapted to be located with the patient's body having a module housing enclosing an air chamber which encloses the barometric pressure sensor. An air vent extends through the module housing for venting the air chamber to atmospheric pressure outside the module housing. A protective vent cover extends across the air vent formed of a material capable of air passage and capable of inhibiting passage of moisture, liquids, and particulate contaminants through the air vent and into the air chamber. In one embodiment, the sensing module is adapted to be worn or carried by the patient and includes operating circuitry and a power supply for powering the barometric pressure sensor and periodically storing sensed atmospheric pressure values as reference pressure data. In another embodiment, the sensing module comprises a percutaneous access device which is adapted to be implanted in the skin and subcutaneous tissue layer of the patient and includes the protective vent cover extending across the air vent formed in the percutaneous access device. The percutaneous access device is coupled with the barometric pressure sensor to provide for an air chamber extending between the protective vent cover and the barometric pressure sensor. The barometric pressure sensor is preferably enclosed within an air chamber of the implantable medical device, and a catheter extends between the air chamber of the implantable medical device and the percutaneous access device.