System for Repetitive Measurements of Cardiac Output in Freely Moving Individuals

a technology for detecting the parameters of the cardiovascular system and repeating the measurement, which is applied in the field of cardiac output detection, can solve the problems of severe risks to patients, the placement of the catheter in place is expensive and invasive, and the catheter is difficult to remov

Inactive Publication Date: 2008-01-31
ALFRED E MANN INST FOR BIOMEDICAL ENG AT THE UNIV OF SOUTHERN CALIFORNIA
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

[0024] In another aspect of cardiovascular measurement devices and methods, a noninvasive, mobile, self-contained, stand alone system can be used to repetitively perform the cardiac output measurements in freely moving individuals. Th

Problems solved by technology

Thermodilution measurements of cardiac output are disadvantageous for several reasons.
First, placement of the thermodilution balloon catheter is an expensive and invasive technique requiring a sterile surgical field.
Second, the catheter left in place has severe risks to the patient such as local infections, septicemia, bleeding, embolization, catheter-induced damage of the carotid, subclavian and pulmonary arteries, catheter retention, pneumothorax, dysrrhythmias including ventricular fibrillation, perforation of the atrium or ventricle, tamponade, damage to the tricuspid values, knotting of the catheter, catheter transection and endocarditis.
Third, only specially trained physicians can insert the balloon catheter for thermodilution cardiac output.
Last, thermodilution measurements of the cardiac output are too invasive to be performed in small children and infants.
Dye-dilution measurements of cardiac output have been found to be disadvantageous for several reasons.
First, arterial blood withdrawal is time consuming, labor intensive and depletes the patient of valuable blood.
This calibration process can be very laborious and time consuming in the context of the laboratory where several samples must be run on a daily basis.
Further, technical difficulties arise in extracting the dye concentration from the optical absorbance measurements of the blood samples.
However, as described a

Method used

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  • System for Repetitive Measurements of Cardiac Output in Freely Moving Individuals
  • System for Repetitive Measurements of Cardiac Output in Freely Moving Individuals
  • System for Repetitive Measurements of Cardiac Output in Freely Moving Individuals

Examples

Experimental program
Comparison scheme
Effect test

example 1

[0129] Experimental system and method. An implementation of the system and method of this invention was tested in rats. The excitation source was a 775 nm pulsed diode laser and the fluorescence was detected with a detector being a photomultiplier (PMT) with extended response in the near-infrared range of the spectrum (FIG. 1). Optic fibers were placed in close contact with the skin of the animal's ear for the excitation and detection of the indicator within the blood stream. After injection of a 100□l bolus of ICG (0.0075 mg / ml) into the jugular vein of a rat, the fluorescence intensity trace (indicator concentration recording) was measured transcutaneously at the level of the rat's ear using reflection mode detection of emissions (FIG. 2).

[0130] Calculation of blood volume and cardiac output. The initial rapid rise and rapid decay segments of the fluorescence intensity trace represent the first pass of the fluorescent indicator in the arterial vasculature of the animal. Such a wa...

example 2

A. A Sample Method and System for Measuring Cardiac Output and Blood Volume

[0135] Experiments have been performed in New Zealand White rabbits (2.8-3.5 Kg) anesthetized with halothane and artificially ventilated with an oxygen-enriched gas mixture (FiO2˜0.4) to achieve a SaO2 above 99% and an end-tidal CO2 between 28 and 32 mm Hg (FIG. 4). The left femoral artery was cannulated for measurement of the arterial blood pressure throughout the procedure. A small catheter was positioned in the left brachial vein to inject the indicator, ICG. Body temperature was maintained with a heat lamp.

[0136] Excitation of the ICG fluorescence was achieved with a 780 nm laser (LD head: Microlaser systems SRT-F780s-12) whose output was sinusoidally modulated at 2.8 KHz by modulation of the diode current at the level of the laser diode driver diode (LD Driver: Microlaser Systems CP 200) and operably connected to a thermoelectric controller (Microlaser Systems: CT15W). The near-infrared light output wa...

example 3

Comparison with Thermodilution Method

[0161] Experimental methodology. Other experiments were performed in New Zealand White rabbits using the methodology described for the preceding example 2. In addition, a 4 F thermodilution balloon catheter was inserted into the right femoral vein and advanced until the thermistor reached the main pulmonary artery. Correct placement of the catheter tip was verified visually through the thoracotomy. The catheter was connected to a cardiac output computer to measure the thermodilution cardiac output. Cardiac output measurements were obtained with the present method (COICG) and the comparison thermodilution method (COTD) during baseline conditions, reduced flow conditions resulting from vagal stimulation, and increased flow conditions resulting from blood volume expansion with saline.

[0162] Results. Average values of COICG and COTD measured in baseline conditions in the 10 animals were 412 (±13) ml / min and 366 (±11) ml / min, respectively, in the ex...

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Abstract

A system for evaluating the cardiovascular system parameters using indicator dilution and non-invasive or minimally invasive detection and calibration methods are disclosed. Intravascular indicators are stimulated, and emissions patterns detected for computation of cardiac output, cardiac index, blood volume and other indicators of cardiovascular health.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS [0001] This application is a continuation-in-part of U.S. patent application Ser. No. 10 / 847,480, filed May 17, 2004, entitled “Measurement of Cardiac Output and Blood Volume by Non-Invasive Detection of Indicator Dilution;” which is Continuation of U.S. patent application Ser. No. 10 / 153,387, filed May 21, 2002 (now U.S. Pat. No. 6,757,554, issued Jun. 29, 2004) entitled “Measurement of Cardiac Output and Blood Volume by Non-Invasive Detection of Indicator Dilution.” This application also relates to U.S. patent application Ser. No. 11 / 625,184 filed Jan. 19, 2007 entitled “Method and Apparatus for Measurement of Cardiac Output and Blood Volume by Non-Invasive Detection of Indicator Dilution”; U.S. patent application Ser. No. 11 / 744,147 filed May 3, 2007 entitled “Method for Dye Injection for The Transcutaneous Measurement of Cardiac Output”; and U.S. patent Ser. No. 11 / 744,157 filed May 3, 2007 entitled “Method and Apparatus for Measurement of...

Claims

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Application Information

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IPC IPC(8): A61B5/02
CPCA61B5/0261A61B2503/40A61B2560/0223A61B5/0275
Inventor BLANCO, CESARRICHMOND, FRANCESHOLSCHNEIDER, DANIEL P.MAAREK, JEAN-MICHEL I.
Owner ALFRED E MANN INST FOR BIOMEDICAL ENG AT THE UNIV OF SOUTHERN CALIFORNIA
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