Methods for monitoring and optimizing central venous pressure and intravascular volume
First Claim
1. A method for non-invasively determining and optimizing Central Venous Pressure (CVP) comprising the steps of:
- applying a controllable pressure to a vein of interest at a non-distal point of a patient;
taking pressure and volume measurements from the patient to generate data points;
plotting intravascular measurements based on the data points as pressure and volume change curves;
determining from the pressure and volume and change curves an overall slope of the volume change curve and a maximum slope of the volume change curve; and
determining the CVP based on pressure at the volume change curve maximum slope.
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Abstract
Central Venous Pressure (CVP) is non-invasively determined with accuracy comparable to invasive measurement techniques. To do so, curves are plotted based on non-invasively determined patient information obtained by applying a controllable variable (pressure) to a vein of interest at a non-distal point and taking certain measurements (such as pressure and volume measurements) from the patient. An example of a controllable variable is voltage applied in incremental inflation/deflation of a vascular cuff (1). A curve is plotted based on datapoints (such as a volume increase curve or a volume decline curve). Pertinent, accurate CVP and/or blood volume information is obtained from the slope of the non-invasive-based curve. Accurate CVP information is provided without the risks and disadvantages of invasive measurements.
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Citations
33 Claims
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1. A method for non-invasively determining and optimizing Central Venous Pressure (CVP) comprising the steps of:
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applying a controllable pressure to a vein of interest at a non-distal point of a patient; taking pressure and volume measurements from the patient to generate data points; plotting intravascular measurements based on the data points as pressure and volume change curves; determining from the pressure and volume and change curves an overall slope of the volume change curve and a maximum slope of the volume change curve; and determining the CVP based on pressure at the volume change curve maximum slope. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24)
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25. A method of non-invasively determining Central Venous Pressure (CVP) comprising the steps of:
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making an identified pressure measurement during a cuff inflation and/or deflation procedure; and subtracting from the pressure measurement a baseline cuff pressure, to determine CVP according to CVP˜
Pmax slope−
P0, where P0 is a measured initial pre-inflation pressure in an inflatable vascular cuff applied at a non-distal part of a patient and Pmax slope is a measured pressure at a maximally sloping part of a curve consisting of data points (x,y), with x being a volume variable and y being time. - View Dependent Claims (26, 27)
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28. A system for non-invasively determining Central Venous Pressure (CVP) comprising:
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a inflatable cuff for applying a controllable pressure to a vein of interest at a non-distal point of a patient; a data processing system; a cuff inflator receiving control instructions from and sending pressure data to the data processing system, the cuff inflator controlling the inflatable cuff in response to control instructions from the data processing system; a non-invasive volume sensitive detector attached to the patient and sending volume data to the data processing system, said volume data varying in response to pressure applied by the inflatable cuff; said data processing system plotting intravascular measurements based on the data points as pressure and volume change curves, determining from the pressure and volume and change curves an overall slope of the volume change curve and a maximum slope of the volume change curve, and determining the CVP based on pressure at the volume change curve maximum slope. - View Dependent Claims (29, 30, 31, 32, 33)
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Specification