Noninvasive systems for blood pressure measurement in arteries

Abstract

Hardware and software methodology are described for a non-invasive approach to blood pressure measurement in pulmonary artery and systemic arteries by using wall displacement and blood velocity that are measured using ultrasound, microwave techniques and/or other radiofrequency (RF) techniques.

1 . A system for noninvasive determination of blood pressure comprising:
 at least one sensor that produces a first data set that correlates to distension of a blood vessel and a second data set that correlates to blood velocity within the vessel; and   at least one processor that converts the first data set to measurement of blood vessel distention and the second data set to measurement of blood velocity.   
     
     
         2 . The system of  claim 1 , wherein the processor causes the system to capture the data sets at the beginning of a cardiac cycle. 
     
     
         3 . The system of  claim 2 , wherein the processor selects from the data sets at the beginning of the cardiac cycle. 
     
     
         4 . The system of  claim 3 , wherein the processor calculates a slope of a D-U loop at the beginning of the cardiac cycle. 
     
     
         5 . The system of  claim 4 , wherein the processor calculates blood pressure based on the slope and the blood vessel distension. 
     
     
         6 . The system of  claim 5 , adapted to record at least one of the first and second data sets, the measurements of blood vessel distention and average blood velocity, or the calculated blood pressure. 
     
     
         7 . The system of  claim 5 , wherein the processor outputs the calculated blood pressure for visual display. 
     
     
         8 . The system of  claim 1 , adapted to produce the first and second data sets at substantially the same location of the blood vessel. 
     
     
         9 . The system of  claim 1 , wherein the at least one sensor is a radiofrequency sensor. 
     
     
         10 . The system of  claim 1 , wherein the at least one sensor is an ultrasound or microwave sensor. 
     
     
         11 . A method of blood pressure estimation, the method comprising:
 selecting a blood vessel;   measuring blood vessel distention and blood velocity with at least one sensor;   calculating, in real time, blood pressure based on the blood vessel distension and blood velocity; and   displaying the calculated blood pressure on an electronic display.   
     
     
         12 . The method of  claim 11 , wherein the blood vessel is a pulmonary or systemic artery. 
     
     
         13 . The method of  claim 11 , wherein calculating includes determining a slope calculated for vessel diameter plotted against blood velocity at the beginning of a cardiac cycle. 
     
     
         14 . The method of  claim 11 , wherein the blood velocity measured is selected from center-line blood velocity and cross-section area average of the velocity. 
     
     
         15 . A computer readable medium having stored thereon instructions, which when executed cause one or more processors to:
 receive input signals from at least one sensor corresponding to blood vessel distention and blood velocity;   determine, using the input signals, vessel distention and blood velocity from sensor;   calculate blood pressure based on the blood vessel distension and blood velocity; and   output a signal corresponding to the calculated blood pressure.   
     
     
         16 . The computer readable medium of  claim 15 , wherein the blood pressure calculation includes determining a slope calculated for vessel diameter plotted against blood velocity at the beginning of a cardiac cycle. 
     
     
         17 . The computer readable medium of  claim 16 , wherein the blood velocity is selected from center-line blood velocity and cross-section area average of the velocity. 
     
     
         18 . The computer readable medium of  claim 16 , wherein the output is selected from instantaneous pressure, systolic/diastolic max/min pressure, pulse pressure, and an entire pressure wave. 
     
     
         19 . The computer readable medium of  claim 18 , wherein the instructions cause the output to be displayed in real time. 
     
     
         20 . The computer readable medium of  claim 18 , wherein the instructions cause the output to be displayed as an average over a number of cycles.