Patent Application
20120289840
The present invention relates to a method that dynamically analyzes the form of pressure wave in cuff recorded during measurement of blood pressure by electronic manometer. The analytic method measures the central arterial systolic blood pressure accurately, and the manometer employing the technology of the present invention can simultaneously measure the traditional peripheral arterial (brachium artery) blood pressure as well as the central arterial blood pressure. The present invention largely improves the accuracy of hypertensive medicine choice and the dosage adjustment.
Abnormality of blood dynamics is usually occurred in hypertension, including enhancement of reflected wave, acceleration of pulse conduction and decrease of compliance. It has been clinically proven that the central arterial pressure is a key factor of recovery from hypertension. The brachium arterial blood pressure value is determined by measurement of the peripheral arterial blood pressure by traditional or electronic manometer, usually being higher than the central arterial blood pressure, such as the ascending aortic and carotid arterial blood pressure value. Due to the different effects of different medications of blood pressure-lowering medicine on the central aortic and peripheral arterial blood pressure, using the brachium arterial systolic and diastolic blood pressure measured alone by traditional or electronic manometer to estimate the central aortic blood pressure may overestimate or underestimate the effect of blood pressure-lowering medicine on the central aortic blood pressure. Hence, it is insufficient to evaluate how well the blood pressure is controlled only by measuring of the brachium arterial blood pressure. There has been a method already which can estimate the waveform and value of ascending aortic systolic blood pressure by recording the radial arterial waveform, the brachium arterial blood pressure, and by a known mathematic formula, the related commercialized product (SphygmoCor, AtCor Medical Pty Limited) has been widely used in clinical trial, and it has been proven that the estimation of the value of ascending aortic systolic blood pressure can show the different effects on the central aortic blood pressure by different medications of blood pressure-lowering medicine. It could predict the risk of patients with cardiovascular disease after medication of different pressure-lowering medicines; hence, the measurement of the central arterial blood pressure played a role in the control of hypertension. Although SphygmoCor can estimate the ascending aortic systolic blood pressure, it needs expensive and complicated accessories and special operation techniques and is not appropriate for widely use in hospital and personal use of a patient.
Patent No. WO/1996/0390 showed an innovation of technology, employing two separated measurement parts (upper arm and wrist) to measure the brachium arterial blood pressure value (by technology of common electronic manometer) and the radial arterial blood pressure waveform (by pen-shaped arterial tonometer) respectively, and then converts the radial arterial blood pressure waveform to the ascending aortic blood pressure waveform by a known mathematic formula, and adjusts the converted ascending aortic blood pressure waveform by the measured brachium arterial blood pressure value. Users can obtain the ascending aortic blood pressure value through the converted ascending aortic blood pressure waveform, which is the commercialized, non-invasive and patented technology of estimating the waveform and value of ascending aortic blood pressure. The product of this patent, invented by an Australian scientist, Dr. Michael F. O'Rourke, needs the expensive pen-shaped pressure tonometer, a laptop, and a specialized analytic program. The pen-shaped pressure tonometer is related to the accuracy of the estimated value and needs special operation technique; therefore, the usage of the expensive diagnostic instrument is still limited to research and can not be a personal home care.
U.S. Pat. No. 6,428,482 did not disclose the using of (I) systolic blood pressure of pulse volume recording, X1, (II) last phase systolic blood pressure of pulse volume recording, X2, (III) the value of the area below the waveform during systole and the area below the waveform during diastole dividing the area below the waveform during diastole, X3, and (IV) the pressure of reflected wave hiding beneath the waveform of pressure, X4, to estimate a central arterial blood pressure.
The present invention provides a measuring device of estimating the central arterial blood pressure at remote site (10), which includes:
The present invention further provides a method of estimating a central arterial blood pressure by measuring signals of pulse oscillation of a brachium artery by a cuff, which includes:
The present invention changes the procedure of measuring blood pressure appropriately, and uses the recorded oscillatory wave of pressure pulse in the cuff to do dynamic analysis and then estimates the central aortic systolic blood pressure accurately. The techniques of operation and analysis of the present invention can apply to a common electronic manometer without other expensive accessories. The diagnosis of hypertension can be a revolution while a common electronic manometer has the function to measure the central aortic systolic blood pressure.
The present invention relates to a method of analyzing the oscillatory wave of pressure pulse in the cuff. The present invention use the pressure value obtained from the measurement part (upper arm) to estimate the pressure value of remote parts (ascending aorta or carotid arteries) directly. In detail, the present invention is characterized by the analytic method of oscillatory waveform of pressure pulse used in the cuff of electronic manometer, including the analysis of dynamic oscillatory waveform (the oscillatory waveform recorded during decrease period of pressure in the cuff) and the analysis of static oscillatory waveform (the oscillatory waveform recorded when the pressure in the cuff decreased to certain degree, the so-called pulse volume recording). The analytic method of the present invention includes the techniques of analyzing time and frequency, which estimates the pressure value of remote parts (ascending aorta or carotid arteries) directly through real-time analysis oscillatory waveform of pressure pulse.
As Shown in
The “central artery” refers to carotid arteries or the ascending aorta.
As shown in
Within the measuring device (10) of the present invention, the analytic device (40) can calculate the value of systolic blood pressure, diastolic blood pressure, average pressure, and heart rate. In an embodiment, the recording and saving device (30) can record and save the oscillometric waveform of the pressure in the cuff, which includes the signal of dynamic oscillometric waveform (recorded during decrease period of pressure in the cuff) and signal of static oscillometric waveform (recorded when the pressure in the cuff decreased to certain degree), wherein the static oscillometric waveform is the so-called pulse volume recording.
The present invention further provides a method of estimating a central arterial blood pressure by measuring signals of pulse oscillation of a brachium artery by a cuff, which includes:
As shown in
In an embodiment of the present invention, the measurement of the oscillometric waveform of the pressure in the cuff includes the process of pressure decreasing in the cuff, the moment of the pressure in the cuff decreasing to a certain degree (for example, 60 mmHg) for a certain period, and the oscillometric signal recorded during the process of the pressure re-increasing in the cuff.
50 experimenters participated in this experiment. After completion of routine catheterization, a micromanometer-tipped catheter (model SPC-320, Millar Instruments Inc) placed within the lumen of a standard 7F Judkins coronary artery catheter was advanced in the ascending aorta from right radial artery. The central aortic pressure waveform was recorded simultaneously with the noninvasive pulse volume recording. The recording was repeated during hemodynamic transient: at the peak response of intravenous bolus of 200 ug nitroglycerin. Once the signals had obtained by micromanometer in ascending aorta were recorded, the catheter was pulled back, leaving the micromanometer tip in the right brachial artery beneath the pressure cuff for the brachial pulse volume recording. Again, the invasive brachial pressure waveforms and the noninvasive brachial pulse volume traces were recorded simultaneously. The invasive central aortic and brachial pressure signals were digitized at a rate of 500 Hz on an IBM-compatible personal computer and saved for off-line analysis. The pulse volume recording was performed using a commercially available device (VP-2000, Colin Corporation, Komaki, Japan). The result of the acquired waveforms is shown in
The digitized signals were analyzed using custom software written in our laboratory. Two to 10 consecutive beats of the aortic pressure waves, brachial pressure waves, and the brachial pulse volume traces were signal averaged. Premature beats and beats immediately after premature beats were excluded. The signal-averaged brachial pulse volume recording waveforms were calibrated by matching the mean and diastolic blood pressures of brachial artery pressure measured by the automated oscillometric sphygmomanometer incorporated in the device (VP-2000, Cohn Corporation, Komaki, Japan).
Prediction of Central Systolic Blood Pressure by Statistical Regression Equation of Systolic Blood Pressure Estimated from Calibrated Brachial Pulse Volume Recording
Multiple linear regression analysis was performed for prediction of central aortic systolic blood pressure from parameters obtained from analysis of the calibrated pulse volume recording waveform. Central aortic systolic blood pressure was used as dependent variable. Unvaried correlation analyses of the pulse volume recording waveform parameters with central aortic systolic blood pressure were performed and variables above with p value less than 0.15 were selected as independent variables in the model. Subsequently, four parameters were identified to construct the multi-variate prediction model, including systolic blood pressure of pulse volume recording, last phase systolic blood pressure of pulse volume recording, the value of the area below the waveform during systole and the area below the waveform during diastole dividing the area below the waveform during diastole, and the pressure of reflected wave hiding beneath the waveform of pressure.
Agreements between the predicted SBP-C using our method and the invasively measured SBP-C were examined using the Bland-Altman analysis. The result was shown in
As shown in
(3) bringing factors (I)˜(IV) to a formula, a regression formula Y1=a1X1+a2X2+a3X3+a4X4+b, to take first values of measured central arterial blood pressure Y1 and first values of factor (I) systolic blood pressure of pulse volume recording, X1, factor (II) last phase systolic blood pressure of pulse volume recording, X2, factor (III) the value of the area below the waveform during systole and the area below the waveform during diastole dividing the area below the waveform during diastole, X3, and factor (IV) the pressure of reflected wave hiding beneath the waveform of pressure, X4, into the regression formula, wherein the measured central arterial blood pressure is used as dependent variables; the factors (I)˜(IV) in Step (2) as independent variables, to calculate the formula by multiple regression analysis to get values of parameters a1, a2, a3, a4 and b;
The values of the parameters a1, a2, a3, a4 and b shall not be limited to a single value because the values of the parameters a1, a2, a3, a4 and b will vary depending upon the type of the cuff, the methods of regression analysis, and other determinant factors.
| Number | Date | Country | Kind |
|---|---|---|---|
| 096147043 | Dec 2007 | TW | national |
This application is a Continuation-in-Part application of the Divisional application of the pending U.S. patent application Ser. No. 13/198,000 of the U.S. patent application Ser. No. 12/132,826 filed on Jun. 4, 2008, all of which is hereby incorporated by reference in its entirety. Although incorporated by reference in its entirety, no arguments or disclaimers made in the parent application apply to this divisional application. Any disclaimer that may have occurred during the prosecution of the above-referenced application(s) is hereby expressly rescinded. Consequently, the Patent Office is asked to review the new set of claims in view of the entire prior art of record and any search that the Office deems appropriate.
| Number | Date | Country | |
|---|---|---|---|
| Parent | 12132826 | Jun 2008 | US |
| Child | 13198000 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | 13198000 | Aug 2011 | US |
| Child | 13420807 | US |
