Renal Function Analysis Method and Apparatus

Abstract

A method for measuring a glomerular filtration rate in a mammalian kidney comprises a source of reporter and marker fluorescent molecules. The fluorescent molecules are introduced into the blood stream of a mammalian subject. Over a period of time, a measurement of the intensities of the reporter and marker fluorescent molecules is taken. A ratio is calculated to determine the health of the subject's kidney. This method measures volume of plasma distribution based on a fluorescence of a marker molecule relative to a fluorescence of a reporter molecule.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS[0001]This application claims the benefit of U.S. Provisional Application No. 61 / 046,273, filed on Apr. 18, 2008 which is hereby incorporated by reference as if fully set forth herein.FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT[0002]N / ATECHNICAL FIELD[0003]The invention relates to medical methods and devices used in conjunction with analyzing organ functions. More particularly, the present invention is directed to an apparatus and method used for analyzing and quantifying function of a mammalian kidney.BACKGROUND OF THE INVENTION[0004]Acute kidney injury (AKI) is a serious and deadly disease process affecting 5-10% of all hospitalized patients. The mortality rate in these cases often exceeds 50%. AKI is independently associated with increased mortality rates in several clinical situations, including subsequent to administration of radio contrast dye and cardiovascular surgery. It is often multi-factorial in etiology, especially in critically il...

AI Technical Summary

Benefits of technology

[0035]The optical apparatus of the fifth aspect of the invention may further comprise a first lens for focusing at least one of the first or second fluorescent excitation wavelengths onto the excitation site. A second lens may focus at least one of the first or second emitted fluorescence signals onto one of the first or second means for detecting. A third lens may focus the other of the first or second emitted fluorescence signals onto the other of the first or second means for detecting. A first condenser lens may be provided for minimizing an aberration associated with the first fluorescent excitation wavelength. A second condenser lens may be provided for minimizing an aberration associated with the second fluorescent excitation wavelength. A first dichroic filter may be positioned within the delivery optical path. A second dichroic filter may be positioned within the return optical path. A third dichroic filter may be positioned within the optical device between the delivery optical path and the return optical path.

Problems solved by technology

AKI is independently associated with increased mortality rates in several clinical situations, including subsequent to administration of radio contrast dye and cardiovascular surgery.

Unfortunately, these two approaches are not reliable over the full range of GFR, and neither can be used in AKI, since both muscle mass (creatinine is a breakdown product of creatine, which is an important part of muscle) and GFR determine a patient's serum creatinine level.

However, even these formulas are inaccurate and often misleading in estimating GFR below 20 or above 60 ml / min.

Therefore, this is another reason they cannot be used in the setting of AKI.

Serum creatinine determinations as a measure of GFR may also be severely limiting because of the time it takes to reach equilibrium values required for an accurate conversion.

This slow rise in serum creatinine limits the physician's ability to diagnose the injury for 12-24 hours after the event, and it is also not possible to determine the extent of injury for days.

This has markedly limited the ability to conduct a therapeutic trial in AKI.

It is widely held that beginning therapy after 12-24 hours of AKI may limit the success rate of any potential therapeutic agent.

However, improvements sought utilizing these structural biomarkers may not be significant because they were developed using population results that may not apply to an individual.

Collection of a 24 hour urine and invasive techniques exist to accurately determine a patient's GFR, but these are cumbersome, error prone, expensive, time consuming, or expose the patient to radiation or radio contrast media.

Also, there is no rapid and accurate measurement technique that can determine GFR reliably in patients with acute kidney injury when the serum creatinine is rising.

Unfortunately, the liver may be diseased either acutely or chronically and its ability to perform various vital functions may be limited.

Unfortunately, these tools of detecting liver health are often identical to signs used to detect other major health issue and are often useless when diagnosing and treating a patient with multiple morbidities.

As a result, many liver diseases remain unrecognized until they reach a severe state where metabolic functions and ascites are often more definitive signs.

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