Patent Issued for Method for detecting intravascular volume depletion during a hemodialysis session (USPTO 11458233): Henry Ford Health System

2022 OCT 21 (NewsRx) -- By a News Reporter-Staff News Editor at Insurance Daily News -- Henry Ford Health System (Detroit, Michigan, United States) has been issued patent number 11458233, according to news reporting originating out of Alexandria, Virginia, by NewsRx editors.

The patent’s inventors are Besarab, Anatole (Bloomfield Hills, MI, US), Frinak, Stanley (Farmington Hills, MI, US), Kennedy, John B. (Evanston, IL, US), Sands, Jeffrey J. (Orlando, FL, US), Yee, Jerry (Beverly Hills, MI, US), Zasuwa, Gerard (West Bloomfield, MI, US).

This patent was filed on June 13, 2017 and was published online on October 4, 2022.

From the background information supplied by the inventors, news correspondents obtained the following quote: “Patients with end stage renal disease (ESRD) depend upon regular renal replacement therapy for survival. Typically, non-transplanted ESRD patients receive either hemodialysis or peritoneal dialysis therapy to remove accumulated waste products and excess fluid. Hemodialysis, in particular, is typically performed three times weekly for approximately 3 to 5 hours. The process of hemodialysis removes waste products by diffusion and convection and fluid removal is accomplished by ultrafiltration. During the process of ultrafiltration, fluid is removed from the extracellular space in sufficient quantity to decrease the patients’ pre-dialysis weight to their so-called “estimated dry weight” as prescribed by their physician. This weight target is frequently modified for individual treatments based upon the pre-dialysis nursing assessment of the patient including assessment of the patients’ clinical status, blood pressure, presence of edema, change in the patients’ weight since the end of the previous hemodialysis treatment, their previous post-hemodialysis treatment blood pressure and their tolerance of the previous hemodialysis treatment. A typical ultrafiltration goal is for the removal of 2 Kg-4 Kg (i.e. 2-4 L) of fluid during the hemodialysis treatment. Ultrafiltration during hemodialysis removes fluid from the intravascular space which contains only approximately 5 L of blood (intravascular volume).

“Therefore, maintenance of intravascular volume during ultrafiltration relies upon of refilling of the vascular space from movement of extracellular fluid into the vascular space. If refilling is inadequate, the patient will develop intravascular volume depletion which may result in physiologic responses such as vasoconstriction or increased heart rate in an attempt to maintain cardiac output and adequate blood pressure. Frequently, however, the patient may not be able to adequately compensate for rapid ultrafiltration and may develop signs or symptoms including cramping, dizziness or hypotension. In fact, intradialytic hypotension (IDH) is a frequent complication of hemodialysis and has been reported to occur during 5%-30% of all hemodialysis treatments and is a frequent source of morbidity (Sands J J et al., Hemodial Int. 2014 Apr; 18(2): 415-22). If severe or left untreated, IDH can result in loss of consciousness, circulatory collapse or even death. Early recognition of intravascular volume depletion is important to allow clinical personnel to provide interventions to prevent these patient complications. Such interventions may include decreasing the ultrafiltration rate, administration of IV saline, lowering patients’ heads and raising their legs to increase central vascular volume, increasing dialysate (Na, etc.) in an effort to maintain patients’ blood pressure, protect their cardiac output and correct their volume status.

“In hemodialysis facilities, the current standard of care is to obtain blood pressure measurements and assess the patient clinically every 30 min. This, however, may be insufficient to identify early signs of intravascular volume depletion and to prevent hypotensive episodes. For this reason, clinicians have utilized other measures such as changes in relative blood volume during hemodialysis treatments to help guide volume removal and identify patients at risk for developing hypotension. These measures, however, are often difficult to interpret and are not routinely available in most hemodialysis facilities. Similarly, measurements of cardiac output and peripheral resistance are not available in hemodialysis facilities and with current technology cannot be feasibly performed throughout every hemodialysis treatment, even in research facilities.”

Supplementing the background information on this patent, NewsRx reporters also obtained the inventors’ summary information for this patent: “In one embodiment, a method of detecting intravascular volume depletion in a patient during a hemodialysis session includes measuring venous drip pressure for the patient. With a computer-driven analyzer, the method further includes analyzing the venous drip pressure and automatically and continuously determining a venous access pressure in proximity to a location of needle insertion into a vascular access site of the patient, wherein changes in venous access pressure are representative of changes in intravascular blood pressure. Using the analyzer, the method further includes comparing the venous access pressure to a standard and, if the venous access pressure is outside of a defined range of the standard, determining with the analyzer that the patient is experiencing intravascular volume depletion during the hemodialysis session.

“In another embodiment, a method of detecting intravascular volume depletion in a patient during a hemodialysis session includes measuring venous drip pressure for the patient. With a computer-driven analyzer, the method further includes analyzing the venous drip pressure and automatically and continuously determining a venous access pressure in proximity to a location of needle insertion into a vascular access site of the patient, wherein changes in venous access pressure are representative of changes in intravascular blood pressure. The method further includes repeating the measuring, analyzing and determining steps to determine a plurality of venous access pressure values and calculate a moving average of venous access pressures and, using the analyzer, comparing the moving average of venous access pressures to a standard. If the moving average of venous access pressures is outside of a defined range of the standard, the method includes determining with the analyzer that the patient is experiencing intravascular volume depletion during the hemodialysis session.

“In another embodiment, a method of detecting intravascular volume depletion in a patient during a hemodialysis session includes measuring venous drip pressure for the patient. With a computer-driven analyzer, analyzing the venous drip pressure and automatically and continuously determining a venous access pressure in proximity to a location of needle insertion into a vascular access site of the patient, wherein changes in venous access pressure are representative of changes in intravascular blood pressure. Using the analyzer, the method further includes comparing the venous access pressure to an initial, baseline value determined for the venous access pressure at a starting point of the hemodialysis session and, if the venous access pressure decreases by at least 50% below the baseline value, determining with the analyzer that the patient is experiencing intravascular volume depletion during the hemodialysis session.”

The claims supplied by the inventors are:

“1. A method of noninvasively monitoring intravascular volume depletion in a patient during a hemodialysis session, the method comprising: receiving a measured venous drip pressure for the patient; with a computer-driven analyzer, analyzing the venous drip pressure and automatically and continuously determining a venous access pressure in proximity to a location of needle insertion into a vascular access site of the patient, wherein changes in venous access pressure are representative of changes in intravascular blood pressure; using the analyzer, noninvasively monitoring the intravascular blood pressure by comparing the venous access pressure to a standard during a selected hemodialysis session over a time period of at least 10% of a total period of the selected hemodialysis session; and if the venous access pressure is outside of a defined range of the standard, determining with the analyzer that the patient is experiencing intravascular volume depletion during the selected hemodialysis session.

“2. The method of claim 1, wherein the standard is an initial, baseline value of venous access pressure determined at a starting point of the hemodialysis session.

“3. The method of claim 1, wherein the standard is a rate of change in the venous access pressure over time.

“4. The method of claim 1, further comprising turning off a blood pump of a hemodialysis machine if intravascular volume depletion is detected.

“5. The method of claim 1, further comprising activating an alarm that notifies at least one of the patient or medical personnel of the detected intravascular volume depletion.

“6. The method of claim 1, wherein determining the venous access pressure includes correcting the venous access pressure based on a relative height of a drip chamber and for a viscosity of blood.

“7. A method of noninvasively monitoring intravascular volume depletion in a patient during a hemodialysis session, the method comprising: receiving a measured venous drip pressure for the patient; with a computer-driven analyzer, analyzing the venous drip pressure and automatically and continuously determining a venous access pressure in proximity to a location of needle insertion into a vascular access site of the patient, wherein changes in venous access pressure are representative of changes in intravascular blood pressure; repeating the receiving, analyzing and determining steps to determine a plurality of venous access pressure values and calculate a moving average of venous access pressures; using the analyzer, noninvasively monitoring the intravascular blood pressure by comparing the moving average of venous access pressures to a standard during a selected hemodialysis session over a time period of at least 10% of a total period of the selected hemodialysis session; and if the moving average of venous access pressures is outside of a defined range of the standard, determining with the analyzer that the patient is experiencing intravascular volume depletion during the selected hemodialysis session.

“8. The method of claim 7, wherein the standard is an initial, baseline value of venous access pressure determined at a starting point of the hemodialysis session.

“9. The method of claim 7, wherein the standard is a rate of change in the venous access pressure over time.

“10. The method of claim 7, further comprising turning off a blood pump of a hemodialysis machine if intravascular volume depletion is detected.

“11. The method of claim 7, further comprising activating an alarm that notifies at least one of the patient or medical personnel of the detected intravascular volume depletion.

“12. The method of claim 7, wherein determining the venous access pressure includes correcting the venous access pressure based on a relative height of a drip chamber and for a viscosity of blood.

“13. The method of claim 2, wherein the defined range is a decrease of the venous access pressure of at least 50% below the standard.

“14. The method of claim 1, wherein the venous drip pressure and the venous access pressure are related by a constant, and the comparing step includes comparing the venous access pressure or the related venous drip chamber pressure to the standard.”

For the URL and additional information on this patent, see: Besarab, Anatole. Method for detecting intravascular volume depletion during a hemodialysis session. U.S. Patent Number 11458233, filed June 13, 2017, and published online on October 4, 2022. Patent URL: http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PALL&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.htm&r=1&f=G&l=50&s1=11458233.PN.&OS=PN/11458233RS=PN/11458233

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