Noninvasive hemodynamic analyzer alterable to a continuous invasive hemodynamic monitor

• US 5,584,298 A
• Filed: 10/25/1993
• Issued: 12/17/1996
• Est. Priority Date: 10/25/1993
• Status: Expired due to Term

• Current Assignee: Cardiopuls Medical, Inc.
• Original Assignee: John Kabal
• Inventors: Kabal, John
• Primary Examiner(s): Sykes, Angela D.
• Assistant Examiner(s): NASSER, ROBERT L
• Application Number:
  US08/140,453
• Time in Patent Office: 1,149 Days
• Field of Search: 128/692, 128/713, 128/668, 128/672, 128/670, 128/690, 128/687-89, 128/713, 128/677, 128/680-3
• US Class Current: 600/485
• CPC Class Codes: A61B 5/022 by applying pressure to close blood vessels, e.g. against the skin; Ophthalmodynamometers
• CPC Class Codes: A61B 5/029 Measuring or recording blood output from the heart, e.g. minute volume A61B8/065 takes precedence
• CPC Class Codes: A61B 5/0295 using plethysmography, i.e. measuring the variations in the volume of a body part as modified by the circulation of blood therethrough, e.g. impedance plethysmography
• CPC Class Codes: A61B 5/4884 inducing physiological or psychological stress, e.g. applications for stress testing

Abstract

A noninvasive method for calculating Actual Stroke Volume and Cardiac Output of a human heart uses computerized algorithms, and is implemented in a continuous noninvasive hemodynamic analyzer which computes a complete real-time Hemodynamic Profile with ten parameters, in both rest and exercise modes. Inputs are received noninvasively by the analyzer, and a cascade of algorithms are used to calculate Stroke Volume, Ejection Fraction and Acceleration Index in Rest and Exercise. The analyzer displays or prints a summary in graphical form.

Claims

1. A method of electronically determining cardiac parameters in a human patient in the presence of a regular heart rate pattern, comprising the steps of:

a) Providing a computerized heart data collection and analysis apparatus including means for obtaining actual heart rate and blood pressure values for the patient;

b) Using the apparatus, obtaining and storing in the computer a set of input parameters including actual heart rate, blood pressure, sex, weight, age and height of the patient;

c) Determining a maximum heart rate for the patient based on at least one of said input parameters and calculating a % heart rate based on the actual heart rate and the maximum heart rate;

d) Calculating ideal systolic blood pressure and ideal diastolic blood pressure for the patient at the % heart rate;

e) Calculating a preliminary ideal stroke volume based on the ideal systolic blood press and the ideal diastolic blood pressure;

f) Calculating a preliminary ideal cardiac output value based on the preliminary ideal stroke volume;

g) Indexing said preliminary ideal cardiac output value to an ideal body surface area for the patient to obtain a preliminary ideal cardiac index, and adjusting said preliminary ideal cardiac index according to patient age to obtain an ideal cardiac index;

h) Calculating actual cardiac stroke volume based on the actual heart rate, blood pressure, and the difference between the ideal cardiac index and preliminary ideal cardiac index; and

i) using the computerized heart data collection and analysis apparatus, providing an output to an operator representing the calculated actual cardiac stroke volume.

2. The method of claim 1 including the further step of determining whether the patient heart rate is less than 40% of the maximum heart rate, and if so, compensating for the decreased heart rate by correspondingly increasing the calculated value of the stroke volume.

3. The method of claim 1 including the further step of calculating a hemodynamic profile including the following parameters:

Mean Arterial Blood Pressure, Cardiac Index, End Diastolic Index, Stroke Index, % Ejection Fraction, Acceleration Index, % Max. Heart Rate, Systemic Vascular Resistance Index, Lea Cardiac Work Index, and Oxygen Delivery Index.

4. The method of claim 3 wherein said Acceleration Index is calculated by:

##EQU15## where ##EQU16## and X=1 for male patients, X=1/3 for female patients.

5. The method of claim 3 wherein % Ejection Fraction is calculated by a two step process wherein

In the first step an Ideal EF is calculated and adjusted to Heart Rate according to EF_Ideal =((% Heart Rate.Actual-40) * 0.1)+57 where % HR.Actual=HR * 100/Max HR and 57 is the theoretical average EF;

and

In the second step the Actual EF is calculated according to;

##EQU17##