Blood pressure monitoring system

Abstract

A blood pressure monitoring system includes a blood pressure measurement device for measuring blood pressure using a cuff, a memory for storing an externally inputted pulse wave propagation time fluctuation threshold, a time interval detection reference point detection section for detecting a time interval detection reference point in a pulse wave on the side of aortae of a living organism, a pulse wave detection section for detecting a pulse wave on the side of peripheral blood vessels appearing with a time lag with respect to the pulse wave on the side of aortae, a pulse wave propagation time measurement section for measuring a pulse wave propagation time based on respective detected outputs from the time interval detection reference point detection section and the pulse wave detection section, an operation device for calculating a pulse wave propagation fluctuation from two measured pulse wave propagation times, a judgment device for judging whether or not the calculated pulse wave propagation time fluctuation exceeds the pulse wave propagation time fluctuation threshold read from the memory, and a control device for controlling the blood pressure measurement device based on an output of the judgment device so that the blood pressure of a subject is measured using the cuff.

What is claimed is:  
     
       1. A blood pressure monitoring system comprising: 
       blood pressure measurement means for measuring blood pressure using a cuff;  
       a memory for storing an externally inputted pulse wave propagation time fluctuation threshold;  
       time interval detection reference point detection means for detecting a time interval detection reference point in an aortic pulse wave of a subject;  
       pulse wave detection means for detecting a pulse wave in peripheral blood vessels appearing with a time lag with respect to the aortic pulse wave;  
       pulse wave propagation time measurement section for measuring a pulse wave propagation time based on respective detected outputs from the time interval detection reference point detection means and the pulse wave detection means;  
       first operation means for calculating a pulse wave propagation fluctuation from two measured pulse wave propagation times;  
       judgment means for judging whether or not the calculated pulse wave propagation time fluctuation exceeds the pulse wave propagation time fluctuation threshold read from the memory; and  
       control means for controlling the blood pressure measurement means based on an output of the judgment means so that the blood pressure of a subject is measured using the cuff.  
     
     
       2. The blood pressure monitoring system according to the  claim 1 , wherein the memory stores a blood pressure fluctuation threshold, and further comprising: 
       second operation means for calculating constants inherent in the subject by dividing a difference between two blood pressure values obtained by the blood pressure measurement means by a difference between the two measured pulse wave propagation times;  
       third operation means for updating the pulse wave propagation time fluctuation threshold within the memory by dividing the blood pressure fluctuation threshold read from the memory by the at least on of said calculated constants inherent in the subject; and  
       auxiliary control means for controlling the operation of updating the pulse wave propagation time fluctuation threshold.  
     
     
       3. A blood pressure monitoring method comprising the steps of: 
       measuring blood pressure using a cuff;  
       storing an externally inputted pulse wave propagation time fluctuation threshold in a memory;  
       detecting a time interval detection reference point in an aortic pulse wave of aortae of a living organism;  
       detecting a pulse wave in peripheral blood vessels appearing with a time lag with respect to the aortic pulse wave;  
       measuring a pulse wave propagation time based on respective detected outputs from the time interval detection reference point detection means and the pulse wave detection means;  
       calculating a pulse wave propagation fluctuation from two measured pulse wave propagation times;  
       judging whether or not the calculated pulse wave propagation time fluctuation exceeds the pulse wave propagation time fluctuation threshold read from the memory; and  
       controlling the blood pressure measurement means based on an output of the judgment means so that the blood pressure of a subject is measured using the cuff.  
     
     
       4. A blood pressure monitoring method comprising the steps of: 
       measuring blood pressure using a cuff;  
       storing a pulse wave propagation time fluctuation threshold and a blood pressure fluctuation threshold in a memory, the thresholds being inputted from an external means;  
       detecting a time interval detection reference point in an aortic pulse wave of a living organism;  
       detecting a pulse wave in peripheral blood vessels appearing with a time lag with respect to the aortic pulse wave;  
       measuring a pulse wave propagation time based on respective detected outputs from the time interval detection reference point detection means and the pulse wave detection means;  
       calculating a pulse wave propagation time fluctuation from two measured pulse wave propagation times;  
       calculating constants inherent in said living organism by dividing a difference between two blood pressure values obtained by the blood pressure measurement means by a difference between the two measured pulse wave propagation times;  
       updating the pulse wave propagation time fluctuation threshold within the memory by dividing the blood pressure fluctuation threshold read from the memory by the at least on of said calculated constants inherent in the subject;  
       controlling the operation of updating the pulse wave propagation time fluctuation threshold;  
       judging whether or not the calculated pulse wave propagation time fluctuation exceeds the pulse wave propagation time fluctuation threshold read from the memory; and  
       controlling the blood pressure measurement means based on an output of the judgment means so that the blood pressure of the subject is measured using the cuff.  
     
     
       5. A blood pressure monitoring apparatus comprising: 
       
         blood pressure measurement means for measuring blood pressure using a cuff;  
       
       
         pulse wave propagation time measurement means for measuring pulse wave propagation time;  
       
       
         control means for controlling said blood pressure measurement means substantially on the basis of the pulse wave propagation time measured by said pulse wave propagation time measurement means, so that the blood pressure of a subject is measured using the cuff. 
       
     
     
       6. The blood pressure monitoring apparatus according to  claim 5 , wherein said control means controls the blood pressure measurement means based on the judgement whether or not pulse wave propagation time fluctuation exceeds a predetermined threshold, so that the blood pressure of the subject is measured using the cuff. 
     
     
       7. The blood pressure monitoring apparatus according to  claim 6 , further comprising: 
       
         updating means for updating said predetermined threshold. 
       
     
     
       8. The blood pressure monitoring apparatus according to  claim 7 , wherein said updating means updates said predetermined threshold by modifying a constant inherent in the subject which is represented in the relationship between blood pressure and pulse wave propagation time. 
     
     
       9. The blood pressure monitoring apparatus according to  claim 7 , wherein said updating means updates on the basis of at least two pairs of information of blood pressure values, obtained by said blood pressure measurement means, and pulse wave propagation times, obtained by said pulse wave propagation time measurement means. 
     
     
       10. The blood pressure monitoring apparatus according to  claim 7 , wherein said updating means comprises: 
       
         first operation means for calculating a constant inherent in the subject by dividing a difference between two blood pressure values obtained by the blood pressure measurement means by a difference between the two measured pulse wave propagation times;  
       
       
         second operation means for updating said predetermined threshold by dividing a second predetermined threshold by said calculated constant inherent in the subject; and  
       
       
         auxiliary control means for controlling the operation of updating said predetermined threshold. 
       
     
     
       11. The blood pressure monitoring apparatus according to  claim 5 , wherein said pulse wave propagation time measuring means includes an electrode to be attached to the subject, and senses an electrocardiographic wave for detecting a time interval detection reference point. 
     
     
       12. The blood pressure monitoring apparatus according to  claim 5 , wherein said pulse wave propagation time measuring means includes at least one of a photoelectric pulse wave sensor and a pressure pulse wave sensor for detecting a time interval detection reference point in an aortic pulse wave of a subject. 
     
     
       13. The blood pressure monitoring apparatus according to  claim 5 , wherein said pulse wave propagation time measuring means includes a photoelectric pulse wave sensor for measuring a pulse wave at a peripheral blood vessel. 
     
     
       14. The blood pressure monitoring apparatus according to  claim 11 , wherein said electrocardiographic wave is an R wave. 
     
     
       15. A blood pressure monitoring system comprising: 
       
         blood pressure measurement means for measuring blood pressure using a cuff;  
       
       
         pulse wave propagation time measurement means for measuring a pulse wave propagation time;  
       
       
         first operation means for calculating a pulse wave propagation fluctuation from two measured pulse wave propagation times;  
       
       
         judgment means for judging whether or not the calculated pulse wave propagation time fluctuation exceeds a first predetermined threshold; and  
       
       
         control means for controlling the blood pressure measurement means based on an output of the judgment means so that the blood pressure of a subject is measured using the cuff. 
       
     
     
       16. The blood pressure monitoring system according to the  claim 15 , further comprising: 
       
         second operation means for calculating constants inherent in a subject by dividing a difference between two blood pressure values obtained by the blood pressure measurement means by a difference between the two measured pulse wave propagation times;  
       
       
         third operation means for updating said first predetermined threshold by dividing a second predetermined threshold by the at least one of said calculated constants inherent in the subject; and  
       
       
         auxiliary control means for controlling the operation of updating said first predetermined threshold. 
       
     
     
       17. A blood pressure monitoring method comprising the steps of: 
       
         measuring blood pressure using a cuff;  
       
       
         measuring a pulse wave propagation time;  
       
       
         calculating a pulse wave propagation time fluctuation from two measured pulse wave propagation times;  
       
       
         judging whether or not the calculated pulse wave propagation time fluctuation exceeds a predetermined threshold; and  
       
       
         controlling measurement of blood pressure in the measuring step based on a result of the judging step so that the blood pressure of a subject is measured using the cuff. 
       
     
     
       18. A blood pressure monitoring method comprising the steps of: 
       
         measuring blood pressure using a cuff;  
       
       
         measuring a pulse wave propagation time;  
       
       
         calculating a pulse wave propagation time fluctuation from two measured pulse wave propagation times;  
       
       
         calculating constants inherent in said living organism by dividing a difference between two blood pressure values obtained by the blood pressure measurement means by a difference between the two measured pulse wave propagation times;  
       
       
         updating a first predetermined threshold by dividing a second predetermined threshold by at least one of said calculated constants inherent in the subject;  
       
       
         judging whether or not the calculated pulse wave propagation time fluctuation exceeds said first predetermined threshold; and  
       
       
         controlling the measuring step based on a result of the judging step so that the blood pressure of a subject is measured using the cuff.