Patent ID: 7641619

Claim:
A system for determining gauge pressure within a patient's body, comprising: an implantable medical device including at least one sensor configured to sense absolute pressure at a location within the body; an acoustic transducer operable to wirelessly transmit absolute pressure information to at least one device located inside or outside of the body, the absolute pressure information including an absolute pressure value corresponding to the absolute pressure sensed by the implantable medical device; a switch coupled between the acoustic transducer and an energy storage device, the energy storage device adapted to supply operating current to an electrical circuit within the implantable medical device upon the acoustic transducer receiving an acoustic wake-up signal from an acoustic energy source, the switch configured to actuate the implantable medical device between an inactive state, in which the operating current is limited from flowing from the energy storage device to the electrical circuit, and an active state that allows operating current to flow from the energy storage device to the electrical circuit; and a remote device operable to: receive the absolute pressure value; and calculate a gauge pressure value based at least in part on the absolute pressure value.