Injectable Hemodynamic Monitoring Devices, Systems and Methods

A hemodynamic monitoring method including patient blood pressure monitoring using a subcutaneously placed sensor implant having first and second ultrasound sensors spaced apart at fixed distance, the method comprising:

• receiving an ultrasound imaging signal from the first ultrasound sensor depicting imaging of a target blood vessel at a first sensing location;
• detecting a cardiac cycle pulse in the first imaging signal;
• receiving an ultrasound imaging signal from the second ultrasound sensor depicting imaging of the target blood vessel at a second sensing location spaced at a sensing distance from the first sensing location;
• detecting the cardiac cycle pulse in the second imaging signal;
• determining the sensing distance based on the fixed distance and the first and second imaging signals;
• measuring time between the detection of the cardiac cycle pulse at the first and second sensing locations;
• detecting patient movement during a timeframe encompassing the detecting of the cardiac cycle pulse at the first and second sensing locations;
• and
• transmitting a signal containing data representing the detected patient movement, determined sensing distance and measured time for receipt at a computing device outside a patient's body configured to determine patient blood pressure during the timeframe based on said data contained in the transmitted signal.

A hemodynamic monitoring method, comprising:

• (a) subcutaneously placing a sensor implant in a patient in tissue at a placement location outside a target blood vessel within about 2 mm to about 50 mm of the target blood vessel, said implant comprising at least one sensor configured to detect changes in vessel diameter at first and second spaced apart sensing locations along said vessel, wherein a distance between said first and second sensing locations along said vessel varies based on orientation of the implant with respect to the vessel;
• (b) with said sensor implant—
• detecting vessel diameter at the first and second sensing locations;
• and
• generating a data stream correlated to a sensing period, the data stream comprising—
• data representative of a change in target vessel diameter at the first sensing location,
• data representative of a change in target vessel diameter at the second sensing location,
• data representative of the distance between the first and second sensing locations,
• data representative of a time difference between the change in target blood vessel diameter at the first sensing location and the second sensing location,
• data representative of patient movement or change in position, and
• data representative of vessel inner and outer diameter;
• and
• (c) transmitting said data stream to an external system, whereby said data stream is accessible by a computing device to determine pulse wave velocity for the vessel and patient blood pressure during the sensing period based on said data stream.

A hemodynamic sensor system, comprising:

• a sensor implant, comprising a housing configured and dimensioned to be delivered subcutaneously through a hollow introducer sheath into tissue adjacent a target blood vessel in a patient, and at least one tissue fixation feature on an outer surface of the housing, the sensor implant further comprising within the housing:
• at least one sensor module configured to detect changes in one or more physiological parameters indicative of patient hemodynamic condition, wherein at least one said sensor module comprises an ultrasound transducer;
• and
• a communication module communicating with the at least one sensor module to transmit one or more signals comprising signals representative of the detected changes to an external receiver.