초록 ▼

An implantable intracranial pressure (ICP) telemetry transmitter. Data transmission is accomplished by means of a radio frequency (RF) link coupled to a silicon piezoresistive pressure transducer. Electrostatic bonding of this transducer onto a tubular glass support provides long-term stability, str

An implantable intracranial pressure (ICP) telemetry transmitter. Data transmission is accomplished by means of a radio frequency (RF) link coupled to a silicon piezoresistive pressure transducer. Electrostatic bonding of this transducer onto a tubular glass support provides long-term stability, stress isolation and a hermetic package. Because of the large temperature coefficient of the electrostatically bonded pressure transducer (-6 to -9 mm Hg/°C.), a temperature sensor is added to allow temperature compensation to be carried out. Pulse code modulation is employed to assure accurate data transmission. Use of low duty cycle pulse powering techniques lowers the power consumption of the telemeter. The complexity of the electronics is reduced by the use of a custom integrated circuit. Two lithium batteries can provide more than one month of continuous operation and an RF command receiver provides ON/Off control of the telemeter to extend the lifetime of the telemeter.

대표청구항 ▼

Apparatus for monitoring intacranial pressure in a subject, said apparatus comprising: a pressure transducer for monitoring pressure variations and producing an analog electronic signal output related to said pressure variations; means for coupling a fluid pressure from an intracranial cavity to sai

Apparatus for monitoring intacranial pressure in a subject, said apparatus comprising: a pressure transducer for monitoring pressure variations and producing an analog electronic signal output related to said pressure variations; means for coupling a fluid pressure from an intracranial cavity to said transducer; transmitter means having an analog to digital converter for converting said analog electronic signal output from said transducer into a sequence of digitial data pulses to encode said pressure into a communication signal suitable for transmission to a remote receiver, said transmitter including switching means responsive to an external signal for switching said transmitter from a quiescent low power state to a higher power transmit state and circuitry coupled to said analog to digital converter for modulating the time between transmission of said sequence of digital data pulses in response to variations in temperture in a region of said pressure transducer; and means for hermetically encapsulating said transducer and said transmitter means having a through passage to accommodate said means for coupling.