System for management and prevention of venous pooling

Abstract

A monitoring system (1) comprises sensors (102) adapted to be worn by a user, and, a processor (101, 302) linked with the sensor. The processor receives sensor data and processes this data to determine user posture data including data indicative of vertical distance between level of the user's heart and ankle (Δh, Vd 1, Vd2, Vd3). Based on the posture data together with a value for degree of user chronic venous insufficiency and/or blood density, generate an estimate of user static venous pressure while the user is static, without calf muscle pump activity. The processor (101, 302) also processes the sensor data to determine if there is calf muscle pump activity, and generates an estimate of user active venous pressure according to the static venous pressure estimate, rate of calf muscle activity, and a value for degree of user chronic venous insufficiency. The processor (101, 302) may generate the venous pressure estimate in real time, and may control an NMES device accordingly.

1 - 39 . (canceled) 
     
     
         40 . A monitoring system comprising:
 at least one sensor adapted to be worn by a user; and   a processor linked with the sensor, wherein the processor is adapted to:
 receive sensor data and process said sensor data to determine user posture data including data indicative of vertical distance between a level of the user's heart and ankle; 
 based on said posture data together with blood density, generate in real time an estimate of user static venous pressure while the user is static, without calf muscle pump activity; 
   process said sensor data to determine a change in user posture; and   start or reset a timer on determining a change in user posture.   
     
     
         41 . The monitoring system as claimed in  claim 40 , wherein the processor is adapted to:
 compare a value of the timer to a pre-defined time threshold for maintaining a single user posture; and   provide audio, visual or tactile feedback to the user if the timer value exceeds the pre-defined time threshold.   
     
     
         42 . The monitoring system as claimed in  claim 40 , wherein the processor is adapted to:
 calculate a pressure-time integral value by multiplying an average user static venous pressure for a user posture by a value of the timer;   compare the pressure-time integral value to a pre-defined pressure-time integral threshold; and   provide audio, visual or tactile feedback to the user if the pressure-time integral value exceeds the predefined pressure-time integral threshold.   
     
     
         43 . The monitoring system as claimed in  claim 40 , wherein the processor is adapted to time stamp sensor data. 
     
     
         44 . The monitoring system as claimed in  claim 40 , wherein the processor is located on an external device for post-processing sensor data. 
     
     
         45 . The monitoring system as claimed in  claim 40 , wherein the processor is adapted to communicate the venous pressure data to one or more external devices. 
     
     
         46 . A monitoring system comprising:
 at least one sensor adapted to be worn by a user; and   a processor linked with the sensor, wherein the processor is adapted to:
 receive sensor data and process said sensor data to determine user posture data including data indicative of vertical distance between a level of the user's heart and ankle; 
 based on said user posture data together with blood density, generate in real time an estimate of user static venous pressure while the user is static, without calf muscle pump activity. 
   
     
     
         47 . The monitoring system as claimed in  claim 46 , wherein the processor is adapted to process said sensor data to determine if there is calf muscle pump activity. 
     
     
         48 . The monitoring system as claimed in  claim 47 , wherein the processor is adapted to generate an estimate of user active venous pressure according to said user static venous pressure and a value for degree of user chronic venous insufficiency, if the processor determines that there is calf muscle pump activity. 
     
     
         49 . The monitoring system as claimed in  claim 48 , wherein the processor is adapted to generate the estimate of user active venous pressure based additionally on a rate of calf muscle pump activity. 
     
     
         50 . The monitoring system of  claim 49 , wherein the processor is adapted to estimate a rate of calf muscle pump activity from rapid changes in acceleration caused by impact forces during impact of the user's heel during calf muscle pump activity. 
     
     
         51 . The monitoring system as claimed in  claim 46 , wherein the at least one sensor is selected from accelerometers, ultrasound range detectors, piezoelectric sensors, gyroscopes, flex sensors, magnetometers, foot switches and smart textiles incorporated electrical sensing elements. 
     
     
         52 . The monitoring system as claimed in  claim 46 , wherein the at least one sensor is adapted to be worn on one or more of a hip, thigh, lower leg, ankle, sole of a foot and trunk of the user. 
     
     
         53 . The monitoring system as claimed in  claim 46 , wherein the at least one sensor comprises one or more selected from a hip-worn sensor to detect step counts and postural transitions, a thigh-worn sensor to detect walking, lying, sitting and/or standing events, and a sensor arranged to be worn on the lower leg to measure step counts, distinguish between standing, sitting, and lying and to measure lower leg elevation. 
     
     
         54 . The monitoring system as claimed in  claim 46 , wherein:
 the at least one sensor comprises two tri-axial accelerometers; and   the processor is adapted to analyse static and dynamic accelerometer signals to determine said user posture and to determine user activity data including data indicative of calf muscle pump activity.   
     
     
         55 . The monitoring system as claimed in  claim 54 , wherein one of the accelerometers is adapted to be placed distal to a knee joint of the user, and the other of the accelerometers is adapted to be placed proximal to the knee joint of the user. 
     
     
         56 . The monitoring system as claimed in  claim 46 , wherein the at least one sensor and the processor are incorporated into a garment. 
     
     
         57 . The monitoring system as claimed in  claim 46 , comprising at least two sensors adapted to detect walking, lying, sitting, and/or standing posture events, and wherein the posture data includes:
 a. a first joint angle made by a thigh of the user with a first reference axis;   b. a second joint angle made by a lower leg of the user with a second reference axis;   c. any angle between the first and second reference axes;   wherein the processor is adapted to calculate the vertical distance (Δh) between the level of the heart and the ankle of the user using the length of the thigh (L 1 ), the length of the shank of the leg (L 2 ), the distance from the hip to the level of the heart (Vd 1 ), and the first and second joint angles using determined postural data.   
     
     
         58 . The monitoring system as claimed in  claim 46 , wherein the at least one sensor is adapted to measure acceleration and/or tilt of a limb segment in one or more axes. 
     
     
         59 . The monitoring system as claimed in  claim 46 , wherein:
 the at least one sensor is adapted to continuously record data; and   the processor is adapted to process sensor data to provide a continuous estimate of user venous pressure.   
     
     
         60 . A monitoring system comprising:
 at least one sensor adapted to be worn by a user; and   a processor adapted to:
 continuously calculate a vertical distance between a heart and an ankle of a user based on sensor data; 
 based on the calculated vertical distance, continuously estimate one of a user static venous pressure and a user active venous pressure using a first pressure algorithm and a second pressure algorithm respectively.