Means and apparatus for continuously determining cardiac output in a subject
First Claim
1. A method for continuously determining cardiac output (CO) in a subject comprising:
- providing a non-invasive sensor device for continuously measuring arterial blood pressure in a subject;
continuously measuring arterial blood pressure and obtaining arterial blood pressure data with said device;
continuously converting said arterial blood pressure data to a digital signal representative of a pulse contour curve waveform;
continuously calculating heart rate (HR), grade of slope, systolic peak pressure, the presence of reflected waves, and pressure at the dicrotic notch from said digital signal;
determining the area, A, under said pulse contour curve from the start of a pulse to the dicrotic notch of said pulse contour curve;
for any pulse which is reflective, subtracting from said area A any portion, B, of said area A, representing an approximate area due to wave reflection to obtain a stroke area, SA; and
calculating CO as a product of SA and HR.
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Abstract
A method for continuously determining cardiac output (CO) in a subject comprising continuously measuring arterial blood pressure data at a site and converting said arterial blood pressure data to a digital signal representative of a pulse contour curve waveform, calculating heart rate, grade of slope, systolic peak pressure, the presence of reflected waves, and pressure at the dicrotic notch from said digital signal; determining the area, SA, under said pulse contour from the start of a pulse to the dicrotic notch of said pulse contour curve; for any pulse which is reflective, subtracting from said area A any portion, B, of said area A, representing an approximate area due to wave reflection to obtain a stroke area, SA; and calculating CO as a product of SA and HR. Apparatus for continuously determining cardiac output (CO) in a subject comprising means for carrying out each step of the method are also disclosed.
88 Citations
21 Claims
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1. A method for continuously determining cardiac output (CO) in a subject comprising:
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providing a non-invasive sensor device for continuously measuring arterial blood pressure in a subject; continuously measuring arterial blood pressure and obtaining arterial blood pressure data with said device; continuously converting said arterial blood pressure data to a digital signal representative of a pulse contour curve waveform; continuously calculating heart rate (HR), grade of slope, systolic peak pressure, the presence of reflected waves, and pressure at the dicrotic notch from said digital signal; determining the area, A, under said pulse contour curve from the start of a pulse to the dicrotic notch of said pulse contour curve; for any pulse which is reflective, subtracting from said area A any portion, B, of said area A, representing an approximate area due to wave reflection to obtain a stroke area, SA; and calculating CO as a product of SA and HR. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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13. Method in accordance with claim 1 further comprising continuously calculating diastolic pressure, pulse pressure, mean pressure, and diastolic area.
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14. Apparatus for continuously determining cardiac output (CO) in a subject comprising:
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non-invasive sensor means for continuously measuring arterial blood pressure data at a site on said subject; means for continuously converting said arterial blood pressure data to a digital signal representative of a pulse contour curve waveform; means for continuously calculating heart rate (HR), grade of slope, systolic peak pressure, the presence of reflected waves, and pressure at the dicrotic notch from said digital signal; means for determining the area, A, under said pulse contour curve from the start of a pulse to the dicrotic notch of said pulse contour curve; means for subtracting from said area A any portion, B, of said area A, representing an approximate area due to wave reflection to obtain a stroke area, SA; and means for calculating CO as a product of SA and HR. - View Dependent Claims (15, 16, 17)
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18. A method for continuously determining cardiac output in a subject comprising:
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providing a minimally invasive sensor device for continuously measuring arterial blood pressure in a subject; continuously measuring arterial blood pressure and obtaining arterial blood pressure data with said device; continuously converting said arterial blood pressure data to a digital signal representative of a pulse contour curve waveform; continuously calculating heart rate (HR), grade of slope, systolic peak pressure, the presence of reflected waves, and pressure at the dicrotic notch from said signal; determining the area, A, under said pulse contour curve from the start of a pulse to the dicrotic notch of said pulse contour curve; for any pulse which is reflective, subtracting from said area A any portion, B, of said area A, representing an approximate area due to wave reflection to obtain a stroke area, SA; and calculating CO as a product of SA and HR. - View Dependent Claims (19)
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20. Apparatus for continuously determining cardiac output (CO) in a subject comprising:
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minimally invasive sensor means for continuously measuring arterial blood pressure data at a site on said subject; means for continuously converting said arterial blood pressure data to a digital signal representative of a pulse contour curve waveform; means for continuously calculating heart rate (HR), grade of slope, systolic peak pressure, the presence of reflected waves, and pressure at the dicrotic notch from said signal; means for determining the area, A, under said pulse contour curve from the start of a pulse to the dicrotic notch of said pulse contour curve; means for subtracting from said area A any portion, B, of said area A, representing an approximate area due to wave reflection to obtain a stroke area, SA; and means for calculating CO as a product of SA and HR. - View Dependent Claims (21)
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Specification