US20210379206A1 - Compositions and methods for measuring and expanding blood volume - Google Patents
Compositions and methods for measuring and expanding blood volume Download PDFInfo
- Publication number
- US20210379206A1 US20210379206A1 US17/245,842 US202117245842A US2021379206A1 US 20210379206 A1 US20210379206 A1 US 20210379206A1 US 202117245842 A US202117245842 A US 202117245842A US 2021379206 A1 US2021379206 A1 US 2021379206A1
- Authority
- US
- United States
- Prior art keywords
- patient
- blood
- dextran
- volume
- labeled
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
Links
- 210000004369 blood Anatomy 0.000 title claims abstract description 82
- 239000008280 blood Substances 0.000 title claims abstract description 82
- 238000000034 method Methods 0.000 title claims abstract description 41
- 239000000203 mixture Substances 0.000 title abstract description 28
- 229920002307 Dextran Polymers 0.000 claims description 68
- 230000003068 static effect Effects 0.000 claims description 27
- 230000002792 vascular Effects 0.000 claims description 19
- 238000005259 measurement Methods 0.000 claims description 18
- 230000005284 excitation Effects 0.000 claims description 5
- 230000003287 optical effect Effects 0.000 claims description 4
- 239000003058 plasma substitute Substances 0.000 abstract description 49
- 239000000084 colloidal system Substances 0.000 abstract description 32
- 102000004169 proteins and genes Human genes 0.000 abstract description 30
- 108090000623 proteins and genes Proteins 0.000 abstract description 30
- FZWBNHMXJMCXLU-BLAUPYHCSA-N isomaltotriose Chemical compound O[C@@H]1[C@@H](O)[C@H](O)[C@@H](CO)O[C@@H]1OC[C@@H]1[C@@H](O)[C@H](O)[C@@H](O)[C@@H](OC[C@@H](O)[C@@H](O)[C@H](O)[C@@H](O)C=O)O1 FZWBNHMXJMCXLU-BLAUPYHCSA-N 0.000 description 75
- MHMNJMPURVTYEJ-UHFFFAOYSA-N fluorescein-5-isothiocyanate Chemical compound O1C(=O)C2=CC(N=C=S)=CC=C2C21C1=CC=C(O)C=C1OC1=CC(O)=CC=C21 MHMNJMPURVTYEJ-UHFFFAOYSA-N 0.000 description 25
- 102000009027 Albumins Human genes 0.000 description 20
- 108010088751 Albumins Proteins 0.000 description 20
- 210000002381 plasma Anatomy 0.000 description 20
- 239000003550 marker Substances 0.000 description 18
- FAPWRFPIFSIZLT-UHFFFAOYSA-M Sodium chloride Chemical compound [Na+].[Cl-] FAPWRFPIFSIZLT-UHFFFAOYSA-M 0.000 description 14
- 239000000700 radioactive tracer Substances 0.000 description 14
- 239000000243 solution Substances 0.000 description 14
- 229940119744 dextran 40 Drugs 0.000 description 11
- FZWBNHMXJMCXLU-UHFFFAOYSA-N 2,3,4,5-tetrahydroxy-6-[3,4,5-trihydroxy-6-[[3,4,5-trihydroxy-6-(hydroxymethyl)oxan-2-yl]oxymethyl]oxan-2-yl]oxyhexanal Chemical compound OC1C(O)C(O)C(CO)OC1OCC1C(O)C(O)C(O)C(OCC(O)C(O)C(O)C(O)C=O)O1 FZWBNHMXJMCXLU-UHFFFAOYSA-N 0.000 description 9
- BPKIGYQJPYCAOW-FFJTTWKXSA-I calcium;potassium;disodium;(2s)-2-hydroxypropanoate;dichloride;dihydroxide;hydrate Chemical compound O.[OH-].[OH-].[Na+].[Na+].[Cl-].[Cl-].[K+].[Ca+2].C[C@H](O)C([O-])=O BPKIGYQJPYCAOW-FFJTTWKXSA-I 0.000 description 9
- 229940119743 dextran 70 Drugs 0.000 description 9
- 208000020832 chronic kidney disease Diseases 0.000 description 8
- 239000007850 fluorescent dye Substances 0.000 description 8
- 108010010803 Gelatin Proteins 0.000 description 6
- 229920001612 Hydroxyethyl starch Polymers 0.000 description 6
- 241000700159 Rattus Species 0.000 description 6
- 229940119742 dextran 75 Drugs 0.000 description 6
- 239000008273 gelatin Substances 0.000 description 6
- 229920000159 gelatin Polymers 0.000 description 6
- 235000019322 gelatine Nutrition 0.000 description 6
- 235000011852 gelatine desserts Nutrition 0.000 description 6
- 229940027278 hetastarch Drugs 0.000 description 6
- 210000005166 vasculature Anatomy 0.000 description 6
- 238000005516 engineering process Methods 0.000 description 5
- MOFVSTNWEDAEEK-UHFFFAOYSA-M indocyanine green Chemical compound [Na+].[O-]S(=O)(=O)CCCCN1C2=CC=C3C=CC=CC3=C2C(C)(C)C1=CC=CC=CC=CC1=[N+](CCCCS([O-])(=O)=O)C2=CC=C(C=CC=C3)C3=C2C1(C)C MOFVSTNWEDAEEK-UHFFFAOYSA-M 0.000 description 5
- 229960004657 indocyanine green Drugs 0.000 description 5
- 239000011780 sodium chloride Substances 0.000 description 5
- MPLHNVLQVRSVEE-UHFFFAOYSA-N texas red Chemical compound [O-]S(=O)(=O)C1=CC(S(Cl)(=O)=O)=CC=C1C(C1=CC=2CCCN3CCCC(C=23)=C1O1)=C2C1=C(CCC1)C3=[N+]1CCCC3=C2 MPLHNVLQVRSVEE-UHFFFAOYSA-N 0.000 description 5
- 208000009304 Acute Kidney Injury Diseases 0.000 description 4
- 208000033626 Renal failure acute Diseases 0.000 description 4
- 201000011040 acute kidney failure Diseases 0.000 description 4
- 210000004204 blood vessel Anatomy 0.000 description 4
- 230000008859 change Effects 0.000 description 4
- 208000022831 chronic renal failure syndrome Diseases 0.000 description 4
- 230000001268 conjugating effect Effects 0.000 description 4
- 230000021615 conjugation Effects 0.000 description 4
- 208000014674 injury Diseases 0.000 description 4
- 208000017169 kidney disease Diseases 0.000 description 4
- 238000011282 treatment Methods 0.000 description 4
- 230000001154 acute effect Effects 0.000 description 3
- 208000012998 acute renal failure Diseases 0.000 description 3
- 230000008901 benefit Effects 0.000 description 3
- 230000037058 blood plasma level Effects 0.000 description 3
- 238000006243 chemical reaction Methods 0.000 description 3
- 150000001875 compounds Chemical class 0.000 description 3
- 238000000502 dialysis Methods 0.000 description 3
- 239000003814 drug Substances 0.000 description 3
- 230000006870 function Effects 0.000 description 3
- 229920002521 macromolecule Polymers 0.000 description 3
- 238000004519 manufacturing process Methods 0.000 description 3
- 238000012986 modification Methods 0.000 description 3
- 230000004048 modification Effects 0.000 description 3
- 230000008569 process Effects 0.000 description 3
- 230000008733 trauma Effects 0.000 description 3
- 206010015719 Exsanguination Diseases 0.000 description 2
- 241001465754 Metazoa Species 0.000 description 2
- 238000004458 analytical method Methods 0.000 description 2
- 239000000090 biomarker Substances 0.000 description 2
- 210000000601 blood cell Anatomy 0.000 description 2
- 230000006378 damage Effects 0.000 description 2
- 238000010790 dilution Methods 0.000 description 2
- 239000012895 dilution Substances 0.000 description 2
- 239000006185 dispersion Substances 0.000 description 2
- 239000000975 dye Substances 0.000 description 2
- 208000028208 end stage renal disease Diseases 0.000 description 2
- 201000000523 end stage renal failure Diseases 0.000 description 2
- 238000011156 evaluation Methods 0.000 description 2
- GNBHRKFJIUUOQI-UHFFFAOYSA-N fluorescein Chemical compound O1C(=O)C2=CC=CC=C2C21C1=CC=C(O)C=C1OC1=CC(O)=CC=C21 GNBHRKFJIUUOQI-UHFFFAOYSA-N 0.000 description 2
- 230000024924 glomerular filtration Effects 0.000 description 2
- 238000010253 intravenous injection Methods 0.000 description 2
- 210000003734 kidney Anatomy 0.000 description 2
- 230000003907 kidney function Effects 0.000 description 2
- 238000012423 maintenance Methods 0.000 description 2
- 230000004060 metabolic process Effects 0.000 description 2
- 210000000056 organ Anatomy 0.000 description 2
- 230000000737 periodic effect Effects 0.000 description 2
- 230000036470 plasma concentration Effects 0.000 description 2
- 230000002285 radioactive effect Effects 0.000 description 2
- 230000009467 reduction Effects 0.000 description 2
- 238000012360 testing method Methods 0.000 description 2
- ZCYVEMRRCGMTRW-UHFFFAOYSA-N 7553-56-2 Chemical compound [I] ZCYVEMRRCGMTRW-UHFFFAOYSA-N 0.000 description 1
- 208000001647 Renal Insufficiency Diseases 0.000 description 1
- 208000027418 Wounds and injury Diseases 0.000 description 1
- 238000010521 absorption reaction Methods 0.000 description 1
- 230000004075 alteration Effects 0.000 description 1
- 239000003945 anionic surfactant Substances 0.000 description 1
- 239000007864 aqueous solution Substances 0.000 description 1
- 230000036772 blood pressure Effects 0.000 description 1
- 230000003139 buffering effect Effects 0.000 description 1
- 210000004027 cell Anatomy 0.000 description 1
- 230000002596 correlated effect Effects 0.000 description 1
- 238000001514 detection method Methods 0.000 description 1
- 229940079593 drug Drugs 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 210000003743 erythrocyte Anatomy 0.000 description 1
- 239000012530 fluid Substances 0.000 description 1
- 238000002637 fluid replacement therapy Methods 0.000 description 1
- 230000001435 haemodynamic effect Effects 0.000 description 1
- 238000005534 hematocrit Methods 0.000 description 1
- 230000036571 hydration Effects 0.000 description 1
- 238000006703 hydration reaction Methods 0.000 description 1
- 230000028993 immune response Effects 0.000 description 1
- 230000001771 impaired effect Effects 0.000 description 1
- 238000002642 intravenous therapy Methods 0.000 description 1
- PNDPGZBMCMUPRI-UHFFFAOYSA-N iodine Chemical compound II PNDPGZBMCMUPRI-UHFFFAOYSA-N 0.000 description 1
- 229910052740 iodine Inorganic materials 0.000 description 1
- 239000011630 iodine Substances 0.000 description 1
- 201000006370 kidney failure Diseases 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 230000007246 mechanism Effects 0.000 description 1
- 230000007102 metabolic function Effects 0.000 description 1
- 230000004089 microcirculation Effects 0.000 description 1
- 230000000149 penetrating effect Effects 0.000 description 1
- 230000010412 perfusion Effects 0.000 description 1
- 230000035699 permeability Effects 0.000 description 1
- 239000012466 permeate Substances 0.000 description 1
- 239000000047 product Substances 0.000 description 1
- 230000001737 promoting effect Effects 0.000 description 1
- 239000012857 radioactive material Substances 0.000 description 1
- 230000029865 regulation of blood pressure Effects 0.000 description 1
- 238000012959 renal replacement therapy Methods 0.000 description 1
- 238000009256 replacement therapy Methods 0.000 description 1
- 239000001022 rhodamine dye Substances 0.000 description 1
- 238000002798 spectrophotometry method Methods 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 230000000153 supplemental effect Effects 0.000 description 1
- 230000001502 supplementing effect Effects 0.000 description 1
- 230000001225 therapeutic effect Effects 0.000 description 1
- 230000009424 thromboembolic effect Effects 0.000 description 1
- 210000001519 tissue Anatomy 0.000 description 1
- 238000011277 treatment modality Methods 0.000 description 1
- 230000036325 urinary excretion Effects 0.000 description 1
Images
Classifications
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
- A61K49/00—Preparations for testing in vivo
- A61K49/001—Preparation for luminescence or biological staining
- A61K49/0013—Luminescence
- A61K49/0017—Fluorescence in vivo
- A61K49/0019—Fluorescence in vivo characterised by the fluorescent group, e.g. oligomeric, polymeric or dendritic molecules
- A61K49/0021—Fluorescence in vivo characterised by the fluorescent group, e.g. oligomeric, polymeric or dendritic molecules the fluorescent group being a small organic molecule
- A61K49/0041—Xanthene dyes, used in vivo, e.g. administered to a mice, e.g. rhodamines, rose Bengal
- A61K49/0043—Fluorescein, used in vivo
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
- A61K31/00—Medicinal preparations containing organic active ingredients
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
- A61K31/00—Medicinal preparations containing organic active ingredients
- A61K31/70—Carbohydrates; Sugars; Derivatives thereof
- A61K31/715—Polysaccharides, i.e. having more than five saccharide radicals attached to each other by glycosidic linkages; Derivatives thereof, e.g. ethers, esters
- A61K31/716—Glucans
- A61K31/721—Dextrans
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
- A61K38/00—Medicinal preparations containing peptides
- A61K38/16—Peptides having more than 20 amino acids; Gastrins; Somatostatins; Melanotropins; Derivatives thereof
- A61K38/17—Peptides having more than 20 amino acids; Gastrins; Somatostatins; Melanotropins; Derivatives thereof from animals; from humans
- A61K38/38—Albumins
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
- A61K49/00—Preparations for testing in vivo
- A61K49/001—Preparation for luminescence or biological staining
- A61K49/0013—Luminescence
- A61K49/0017—Fluorescence in vivo
- A61K49/0019—Fluorescence in vivo characterised by the fluorescent group, e.g. oligomeric, polymeric or dendritic molecules
- A61K49/0021—Fluorescence in vivo characterised by the fluorescent group, e.g. oligomeric, polymeric or dendritic molecules the fluorescent group being a small organic molecule
- A61K49/0041—Xanthene dyes, used in vivo, e.g. administered to a mice, e.g. rhodamines, rose Bengal
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
- A61K49/00—Preparations for testing in vivo
- A61K49/001—Preparation for luminescence or biological staining
- A61K49/0013—Luminescence
- A61K49/0017—Fluorescence in vivo
- A61K49/005—Fluorescence in vivo characterised by the carrier molecule carrying the fluorescent agent
- A61K49/0054—Macromolecular compounds, i.e. oligomers, polymers, dendrimers
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
- A61K49/00—Preparations for testing in vivo
- A61K49/001—Preparation for luminescence or biological staining
- A61K49/0013—Luminescence
- A61K49/0017—Fluorescence in vivo
- A61K49/005—Fluorescence in vivo characterised by the carrier molecule carrying the fluorescent agent
- A61K49/0056—Peptides, proteins, polyamino acids
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
- A61K9/00—Medicinal preparations characterised by special physical form
- A61K9/0012—Galenical forms characterised by the site of application
- A61K9/0019—Injectable compositions; Intramuscular, intravenous, arterial, subcutaneous administration; Compositions to be administered through the skin in an invasive manner
- A61K9/0026—Blood substitute; Oxygen transporting formulations; Plasma extender
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N33/00—Investigating or analysing materials by specific methods not covered by groups G01N1/00 - G01N31/00
- G01N33/48—Biological material, e.g. blood, urine; Haemocytometers
- G01N33/483—Physical analysis of biological material
- G01N33/487—Physical analysis of biological material of liquid biological material
- G01N33/49—Blood
Definitions
- Volume expanders are used in intravenous therapy for providing additional volume for the circulatory system, typically for fluid replacement, as the patient undergoes a medical procedure.
- Many volume expanders are typically based on solutions of dextrans of various molecular weights, but volume expanders can also include other biocompatible substances such as albumin.
- Blood volume measurement is important for the determination of proper drug dosing, pharmacokinetics, and blood pressure maintenance.
- Blood volume status and blood volume management are indicators of medical conditions such as end stage renal disease, acute kidney injury, chronic kidney disease, and acute blood loss.
- the evaluation of blood volume is important for dialysis patients since there are important implications with regard to the loss of blood volume while on dialysis. This is clinically important for the control of blood pressure and clinical outcomes in patients with end stage renal disease who require dialysis or renal replacement therapy for volume removal.
- ICG-labeled albumin as a tracer indicator has also been disclosed, with the ICG-labeled albumin measured by near infra-red absorption of the molecule.
- both the ICG and radiolabeled methods require a rapid succession of precisely timed blood draws in order to back calculate and estimate the peak concentration of the exogenously introduced albumin at the time when it was fully distributed throughout the vascular compartment.
- the process of taking a succession of five or more blood draws is logistically challenging in busy hospital and critical care environments.
- radiolabeled albumin has a very limited shelf life, and use of radioactive materials requires special handling procedures, and limits the environments where both testing and analysis can occur.
- blood volume expander compositions include an unmodified protein, unmodified colloid or unmodified crystalloid, and a fluorescently-labeled protein, fluorescently-labeled colloid or fluorescently-labeled crystalloid having a first excitation wavelength and a first emission wavelength, the fluorescently-labeled protein, fluorescently-labeled colloid or fluorescently-labeled crystalloid being dynamic within the patient.
- the unmodified protein and the fluorescently-labeled protein are albumin; the unmodified crystalloid and the fluorescently-labeled crystalloid are normal saline or lactated Ringer's solution; and the unmodified colloid and the fluorescently-labeled colloid are gelatin, hetastarch or dextran.
- the unmodified crystalloid is normal saline or lactated Ringer's solution and the fluorescently-labeled tracer marker is a fluorescently labeled protein or colloid.
- the fluorescently-labeled protein, colloid or crystalloid is a dynamic molecule with a molecular weight of less than about 75 kDa, preferably about 40 Kda.
- Such dynamic molecules with a molecular weight of less than about 75 kDa include, for example normal saline, lactated Ringer's solution, gelatin, hetastarch, albumin and dextran.
- the unmodified colloid is Dextran 40, Dextran 70 or Dextran 75.
- the unmodified protein is albumin.
- the unmodified colloid is gelatin or hetastarch.
- the fluorescently-labeled protein or colloid is prepared by conjugating a protein or colloid with at least one fluorescent compound.
- fluorescent compounds include, but are not limited to, Texas Red, fluorescein isothiocyanate (FITC) and 2-SulfhydroRhodamine (2SHR).
- the fluorescent compound is fluorescein isothiocyanate (FITC).
- a series of additional blood samples are taken from the patient or a series of additional non-invasive measurements are made at time intervals of between about 10 and 20 minutes.
- the patient is suffering from kidney disease, acute renal failure or chronic renal failure.
- the patient is suffering from blood loss due to trauma.
- the fluorescently-labeled static molecule is a dextran with a molecular weight greater than about 75 kDa, preferably a dextran with a molecular weight of 150 kDa; and preferably labeled with 2-SulfhydroRhodamine (2SHR).
- the unmodified protein and the fluorescently-labeled protein are albumin; the unmodified crystalloid and the fluorescently-labeled crystalloid are normal saline or lactated Ringer's solution; and the unmodified colloid and the fluorescently-labeled colloid are gelatin, hetastarch or dextran.
- the unmodified crystalloid is normal saline or lactated Ringer's solution and the fluorescently-labeled tracer marker is a fluorescently labeled protein or colloid.
- the unmodified protein is albumin.
- the unmodified colloid is gelatin or hetastarch.
- the unmodified crystalloid is normal saline or lactated Ringer's solution.
- the amount of fluorescently-labeled protein, colloid or crystalloid is present in an amount of from about 0.01% to about 10.0% by weight of unmodified protein, colloid or crystalloid, preferably 0.01% to about 1.0% by weight of unmodified protein, colloid or crystalloid, more preferably about 0.1% by weight of unmodified protein, colloid or crystalloid.
- the fluorescently-labeled protein or colloid is prepared by conjugating a protein or colloid with at least one fluorescent compound.
- fluorescent compounds include, but are not limited to, Texas Red, fluorescein isothiocyanate (FITC) and 2-SulfhydroRhodamine (2SHR).
- the fluorescent compound is fluorescein isothiocyanate (FITC).
- the patient is suffering from kidney disease, acute renal failure or chronic renal failure.
- the patient is suffering from blood loss due to trauma.
- the problems identified in the background as discussed above can be reduced or eliminated through the use of the plasma volume expanders, which incorporate a tracer compatible with the plasma volume expander, such as albumin “spiked” with a small amount of fluorescent albumin or dextran “spiked” with a small amount of a fluorescently-labeled dextran of similar, approximately identical, or identical molecular weight and dispersion characteristics.
- a tracer compatible with the plasma volume expander such as albumin “spiked” with a small amount of fluorescent albumin or dextran “spiked” with a small amount of a fluorescently-labeled dextran of similar, approximately identical, or identical molecular weight and dispersion characteristics.
- blood samples can be periodically or continuously taken from the patient, and the plasma volume concentration can be determined, thereby preventing an over-administration of the expander to the point where renal function can be impaired.
- compositions also are disclosed that include unmodified dextrans as the plasma expander base combined with dextrans which have been labeled with a fluorescent marker added to the base.
- the labeled dextrans are compatible with the unmodified dextrans and can be used to measure their concentration within the plasma in a patient undergoing volume replacement therapy.
- methods for the measurement, adjustment and maintenance of blood volume levels in a patient are accomplished by the use of a fluorescently-labeled detector molecule which is administered to the vascular system of a patient, followed by the administration of a blood volume expander having a different fluorescent characteristic.
- the first injected fluorescently-labeled molecule is used to make an initial determination of blood volume by taking a blood sample from the patient when equilibrium conditions have been established, and calculating the initial blood volume based on the fluorescent emission level of the sample.
- a blood volume expander containing tracer amounts of a differently fluorescent molecule is administered to the patient. Blood volumes can then be adjusted and maintained at the desired level for each individual patient. Blood loss or leakage from the patient can be monitored based on the rate of blood replenishments, or through the use of the novel blood volume expander compositions as described herein.
- the fluorescently-labeled molecule is a large molecular weight dextran (>about 75 kDa) conjugated to one or more fluorescent markers.
- the fluorescently-labeled dextran has a molecular weight of 150 kDA or more and is resident or “static” in the vascular system of the patient, meaning that it remains in the vascular system and is relatively impermeable, i.e. it does not penetrate the blood vessel walls, and is not metabolized, i.e. it is not immediately removed from the vascular space through a metabolic function of the body or an immunological response.
- the fluorescently-labeled dextran can be prepared by conjugating a fluorescent molecule and a macromolecule such as dextran in a conjugation reaction.
- the fluorescent molecule is a compound selected from the group consisting of Texas Red, fluorescein isothiocyanate (FITC) and 2-SulfhydroRhodamine (2SHR), with 2SHR being especially preferred.
- FITC fluorescein isothiocyanate
- 2SHR 2-SulfhydroRhodamine
- novel blood volume expander compositions are provided. Such compositions are prepared by supplementing an unmodified or standard dextran-based volume expander with a small amount of a fluorescently-labeled dextran (of a different fluorescent property than the “static” marker).
- the unmodified dextran volume expander is supplemented with from about 0.01% to about 10.0% by weight of fluorescently-labeled dextran, preferably about 0.01% to about 1.0% by weight, more preferably about 0.1% by weight.
- the fluorescently-labeled dextran is fully compatible with, and similar, nearly identical or identical in molecular weight and size dispersion to the unmodified dextran volume expander; preferably taken from the identical production lot number.
- the unmodified or standardized volume expander is a molecule having a molecular weight of 75 kDa or less.
- the unmodified or standardized volume expander can be albumin (66.5 kDa) or Dextran 40, 70 or 75, i.e. a dextran having a molecular weight of 40 kDa, 70 kDa or 75 kDa, respectively.
- a method for measuring blood volume in a patient comprises the following steps. An initial determination of the blood volume of the patient is made by administering a fluorescently-labeled static molecule to the patient, a blood sample is taken when equilibrium conditions have been established, and the initial blood volume is calculated based on the fluorescent emission level of the sample. Following the initial measurement of blood volume, a blood volume expander is administered to the patient, and a second and possibly, further sets of blood samples are periodically taken once the volume expander has fully distributed and caused an increase in plasma volume. Alternatively, the blood volume can be continuously monitored using a blood line from the patient or through non-invasive techniques, such as with an external optical sensor.
- the patient is suffering from a medical condition such as kidney disease, acute or chronic renal failure, or acute blood loss.
- FIG. 1 is a graph showing plasma volume (as determined using a “static” 150 kDa 2SHR dextran) over time for two exemplary volume expander mixtures in two different partially exsanguinated rats: a 40 kDa dextran spiked with a fluorescein-isothiocyanate (“FITC”) dextran tracer of 40 kDa dextran, and a 70 kDa dextran spiked with a tracer FITC 70 kDa dextran.
- FITC fluorescein-isothiocyanate
- the values are expressed as a % of the control changes in order to highlight the large plasma volume change that occurs with the expanders but not with the exsanguinated rat given identical saline volume but not an expander.
- the increase for rats 1 and 2 are identical with overlapping graph indicators.
- FIG. 3 is a graph showing the decay in concentration over time for two exemplary volume expanders: a 40 kDa dextran spiked with a tracer FITC 40 kDa dextran, and a 70 kDa dextran spiked with a tracer FITC 70 kDa dextran. This graph illustrates that with this method it is possible to determine the concentration of the plasma expander by standard spectrophotometric methods and dilution principles.
- FIG. 4 is a graph showing the relationship between static marker fluorescence and plasma volume in the presence of two exemplary volume expanders: a 40 kDa dextran spiked with a tracer FITC 40 kDa dextran, and a 70 kDa dextran spiked with a tracer FITC 70 kDa dextran.
- a fluorescently-labeled dextran is incorporated in a dextran-based plasma volume expander (i.e. a small known amount of fluorescently-labeled dextran is mixed into a known amount of non-fluorescent dextran) to permit the direct measurement of the amount of expander by measuring the intensity of the signal generated by the fluorescent marker in the volume expander.
- biological marker or “biomarker” is intended to denote a molecular entity designed to be introduced into the vascular system of an animal, preferably a human subject, primarily to measure the function of an organ or vasculature of the animal. It is a biocompatible molecule formed as the conjugation product of one or more fluorescent molecules or dyes and a macromolecule.
- volume expander blood volume expander
- plasma volume expander are used synonymously herein and designate biocompatible compositions designed to restore vascular volume, stabilize circulatory haemodynamics, and maintain tissue perfusion.
- Typical blood volume expanders include saline, albumin and dextran, such as Dextran 40, Dextran 70 and Dextran 75, where the numerical designations refer to the molecular weight of the dextran.
- An “unmodified” or “standard” blood volume expander is a blood volume expander typically given to a patient in a clinical setting, and which does not include a labeled fluorescent component or molecule, or any other type of label or marker as a detection mechanism.
- blood volume or “plasma volume” as used herein denotes the amount of plasma volume within the vascular space including arterial, venous and capillary spaces.
- the blood volume does not include the volume contributed by the blood cells, such as the red blood cells.
- the total blood volume is the blood volume and the volume contributed by the blood cells, which can be determined from the hematocrit or the packed cell volume.
- non-metabolized molecule, or a molecule which is “not metabolized within the subject”, as used herein, is a molecule which is not significantly metabolized during the time in which the measurements are performed. Such molecules typically have a half life of 4 hours or greater in the vascular system of the subject.
- permeable to vessel walls is meant a molecule that can cross vessel walls.
- impermeable to vessel walls means that the molecule cannot cross the vessel walls either through a passive process or an active process.
- a “dynamic molecule” is a molecule of sufficiently low molecular mass to permeate the blood vessel walls or the vasculature of a subject. These molecules are also cleared by the kidney via glomerular filtration with a decrease in clearance as molecular weight increases. Dynamic molecules are known in the art to have a molecular mass of less than about 75 kDa.
- a “static molecule” is a molecule of sufficiently high molecular mass to significantly limit its blood vessel wall permeability and metabolism. Static molecules or markers may reach a quasi-stable vascular concentration for a period of time, although such markers may ultimately be cleared from the vasculature. Static markers are known in the art to have a molecular mass greater than about 75 kDa, preferably about 150 kDa. Such markers can remain in the vasculature for a time period of between about 1 or 2 hours, up to 12 hours or longer, depending on the molecular mass of the marker and rate of metabolism of the marker.
- fluorescently-labeled crystalloid refers to adding a free, unconjugated fluorescent dye such as FITC into the solution.
- the blood volume of a patient can be conveniently measured, adjusted and maintained using the techniques and compositions described herein.
- An initial assessment of the patient's blood volume is conducted, and once the initial assessment is completed, any loss in blood can be supplemented by administering a blood volume expander to the patient.
- Blood volume can be measured directly by utilizing a static fluorescent molecule introduced into the vascular system of the subject by techniques such as disclosed, for instance, in published PCT application PCT/US2013/026277, filed Feb. 15, 2013, the disclosure of which is incorporated herein in its entirety by reference.
- This procedure in general, involves the administration of a static marker suitable for the measurement of initial plasma levels in a subject.
- the fluorescent moiety is conjugated with the dextran in a conjugation reaction by covalent attachment.
- the fluorescent molecule can be a fluorescent dye marker such as a rhodamine dye. Suitable fluorescent molecules include, by way of example, Texas Red, fluorescein isothiocyanate (FITC) and 2-sulfurhodamine (2SHR), with 2SHR being preferred.
- the blood volume expander can be any of a variety of blood volume expanders typically used by a clinician. Suitable blood volume expanders include, for example, saline, albumin and dextran. In a typical clinical environment, the blood volume expander is administered to a subject in order to adjust and maintain the subject's blood volume at a predetermined level. Loss of blood typically occurs as a result of the treatment of the patient for a medical condition wherein blood loss is a significant factor or result. These conditions include severe trauma due to external injuries, and chronic renal disease and/or failure.
- a blood sample can be taken from a patient on a continuous or periodic basis, and the level of the volume expander in the blood can be measured by recording and correlating the presence of the dynamic molecule in the blood sample with the blood volume. This technique can be used to provide an accurate real time measurement of blood volume.
- compositions described herein can be typically used in a clinic or hospital where the treatment of renal disease and renal failure are indicated.
- a standard dose of a Dextran 40 or Dextran 70 blood volume expander is administered to the subject with a small amount of a fluorescently-tagged dextran of approximately the same molecular weight added to the blood volume expander.
- a 30 gram solution of Dextran 40 or Dextran 70 is formulated with about 30 mg of approximately the same molecular weight dextran conjugated to Fluorescein (FITC) (or about 0.1% of fluorescently-labeled dextran by weight of unmodified dextran).
- FITC Fluorescein
- Blood plasma volume and fluorescent concentration (ug/mL) are recorded as a function of time for Dextran 40 and Dextran 70. The results are shown in FIGS. 1, 2 and 3 .
- FIG. 4 shows that when using the static 2SHR 150 kDa marker to measure plasma volume, an increase in plasma volume caused by the volume expanders results in a decrease in the fluorescence of the static marker as it becomes more diluted.
Abstract
A method for measuring, adjusting and maintaining the level of blood volume in a patient is described. A blood volume expander composition includes, in combination, a standard unmodified protein, colloid or crystalloid and a fluorescently-labeled protein, colloid or crystalloid of approximately the same molecular weight. The use of blood volume expanders to measure, adjust and maintain the level of blood volume in a patient also is described.
Description
- This application is a continuation of co-pending U.S. patent application Ser. No. 15/116,650, filed on Aug. 4, 2016, entitled COMPOSITIONS AND METHODS FOR MEASURING AND EXPANDING BLOOD VOLUME, which in turn is a U.S. national stage application under 35 U.S.C. 371 of International Application No. PCT/US2015/14845, filed on Feb. 6, 2015, which in turn claims priority to U.S. Provisional Patent Application No. 61/936,981, filed on Feb. 7, 2014, all of which are incorporated by reference herein in their entirety for all purposes.
- Volume expanders (or plasma volume expanders) are used in intravenous therapy for providing additional volume for the circulatory system, typically for fluid replacement, as the patient undergoes a medical procedure. Many volume expanders are typically based on solutions of dextrans of various molecular weights, but volume expanders can also include other biocompatible substances such as albumin.
- Typical blood expanders used in clinical settings include normal saline, lactated Ringer's solution, albumin, and dextran. Dextran 40, as an example, is in widespread use as a volume expander. In addition to its volume-expanding effects, Dextran 40 is additionally able to improve microcirculation with a relatively low risk of antigenicity, and it can also be used with patients where there is a risk of thromboembolic complications. Dextran 40 has a molecular weight of 40 kDa, but other higher molecular weight dextrans, such as Dextran 70 and Dextran 75, are also used as volume expanders.
- Blood volume measurement is important for the determination of proper drug dosing, pharmacokinetics, and blood pressure maintenance. Blood volume status and blood volume management are indicators of medical conditions such as end stage renal disease, acute kidney injury, chronic kidney disease, and acute blood loss. In addition, the evaluation of blood volume is important for dialysis patients since there are important implications with regard to the loss of blood volume while on dialysis. This is clinically important for the control of blood pressure and clinical outcomes in patients with end stage renal disease who require dialysis or renal replacement therapy for volume removal.
- A commonly used technique for estimating blood volume is based on the indicator dilution technique in which an indicator molecule is mixed and distributed into an unknown volume. An identical amount of the indicator molecule is placed into a known volume. The unknown volume can be measured by comparing the concentration of the indicator between the known and unknown volume. A common indicator molecule is albumin labeled with various dyes, such as radioactive iodine, or the fluorescent dye indocyanine green (ICG). For example, Daxor Corporation (New York, N.Y.) has developed a device for measuring blood volume using albumin labeled with radioactive iodine as the tracer indicator. The use of ICG-labeled albumin as a tracer indicator has also been disclosed, with the ICG-labeled albumin measured by near infra-red absorption of the molecule. However, because albumin is also being cleared from the blood during the time that the test is being conducted, both the ICG and radiolabeled methods require a rapid succession of precisely timed blood draws in order to back calculate and estimate the peak concentration of the exogenously introduced albumin at the time when it was fully distributed throughout the vascular compartment. The process of taking a succession of five or more blood draws is logistically challenging in busy hospital and critical care environments. Additionally, radiolabeled albumin has a very limited shelf life, and use of radioactive materials requires special handling procedures, and limits the environments where both testing and analysis can occur.
- Current technology does not permit a determination of the plasma volume expander concentration in the patient's plasma because the volume expanders do not include a detectable marker, such as a fluorescent label, which is capable of providing the timeliest data on concentration. This can have a significant impact on biometric parameters, such as glomerular filtration rate (GFR) an important kidney function parameter. For instance, blood loss can potentially lead to a reduction in GFR values, while the addition of excess plasma volume expander may exacerbate the reduction in GFR. Using current technology, a clinician can continue to administer a plasma volume expander to a kidney patient in an effort to maintain the plasma volume to the point where the GFR stops due to an elevated level of plasma volume expander beyond efficacious levels.
- It will be readily appreciated that there is a clinical need to develop a minimally invasive method to accurately and inexpensively measure blood volume and critical organ function. The present invention is provided to solve the problems discussed above and other problems, and to provide advantages and aspects not provided by prior techniques. A full discussion of the features and advantages of the present invention is deferred to the following detailed description.
- According to the disclosure, blood volume expander compositions are provided. The blood volume expander compositions include an unmodified protein, unmodified colloid or unmodified crystalloid, and a fluorescently-labeled protein, fluorescently-labeled colloid or fluorescently-labeled crystalloid having a first excitation wavelength and a first emission wavelength, the fluorescently-labeled protein, fluorescently-labeled colloid or fluorescently-labeled crystalloid being dynamic within the patient.
- In various illustrative embodiments, the unmodified protein and the fluorescently-labeled protein are albumin; the unmodified crystalloid and the fluorescently-labeled crystalloid are normal saline or lactated Ringer's solution; and the unmodified colloid and the fluorescently-labeled colloid are gelatin, hetastarch or dextran. In an alternative embodiment, the unmodified crystalloid is normal saline or lactated Ringer's solution and the fluorescently-labeled tracer marker is a fluorescently labeled protein or colloid.
- In further illustrative embodiments, the fluorescently-labeled protein, colloid or crystalloid is a dynamic molecule with a molecular weight of less than about 75 kDa, preferably about 40 Kda. Such dynamic molecules with a molecular weight of less than about 75 kDa include, for example normal saline, lactated Ringer's solution, gelatin, hetastarch, albumin and dextran.
- In one illustrative embodiment, the unmodified colloid is Dextran 40, Dextran 70 or Dextran 75.
- In another illustrative embodiment, the unmodified protein is albumin.
- In another illustrative embodiment, the unmodified colloid is gelatin or hetastarch.
- In yet another illustrative embodiment, the unmodified crystalloid is normal saline or lactated Ringer's solution.
- In further illustrative embodiments, the amount of fluorescently-labeled protein, colloid or crystalloid is present in an amount of from about 0.01% to about 10.0% by weight of unmodified protein, colloid or crystalloid, preferably 0.01% to about 1.0% by weight of unmodified protein, colloid or crystalloid, more preferably about 0.1% by weight of unmodified protein, colloid or crystalloid.
- In further illustrative embodiments, the fluorescently-labeled protein or colloid is prepared by conjugating a protein or colloid with at least one fluorescent compound. Fluorescent compounds include, but are not limited to, Texas Red, fluorescein isothiocyanate (FITC) and 2-SulfhydroRhodamine (2SHR). In certain preferred embodiments, the fluorescent compound is fluorescein isothiocyanate (FITC).
- Also according to the disclosure is described methods for measuring and maintaining blood volume in a patient by administering a fluorescently-labeled static molecule to the vascular system of a patient, the static molecule having a second excitation wavelength and a second emission wavelength, and the static molecule being non-metabolized within the patient; obtaining a first blood sample from the patient or making a first non-invasive measurement of the blood of the patient after the static molecule has reached a fully distributed steady state concentration in the vascular system, and calculating the initial plasma volume based on the emission level in the sample; administering a blood volume expander to the vascular system of the patient; obtaining additional blood samples or non-invasive measurements from the patient following administration of the blood volume expander, and measuring the loss of blood volume expander from the patient.
- In certain illustrative embodiments, the method further includes adding supplemental blood volume expander to the patient as needed.
- In further illustrative embodiments of the method, a series of additional blood samples are taken from the patient or a series of additional non-invasive measurements are made at time intervals of between about 10 and 20 minutes.
- In other illustrative embodiments of the method, the additional blood samples are continuously taken through an indwelling venous catheter or the additional non-invasive measurements are continuously made using an optical sensor.
- In yet other illustrative embodiments of the method, the patient is suffering from kidney disease, acute renal failure or chronic renal failure.
- In other illustrative embodiments of the method, the patient is suffering from blood loss due to trauma.
- In further illustrative embodiments of the method, the fluorescently-labeled static molecule is a dextran with a molecular weight greater than about 75 kDa, preferably a dextran with a molecular weight of 150 kDa; and preferably labeled with 2-SulfhydroRhodamine (2SHR).
- Also according to the disclosure is described the use of a blood volume expander composition for the manufacture of a medicament for measuring, adjusting and maintaining blood volume in a patient.
- In an illustrative embodiment of the use of blood volume expander compositions, the composition is an unmodified protein, unmodified colloid or unmodified crystalloid, and a fluorescently-labeled protein, fluorescently-labeled colloid or fluorescently-labeled crystalloid having a first excitation wavelength and a first emission wavelength, said fluorescently-labeled protein, fluorescently-labeled colloid or fluorescently-labeled crystalloid being non-metabolized within the patient.
- In various illustrative embodiments of the use of blood volume expander compositions, the unmodified protein and the fluorescently-labeled protein are albumin; the unmodified crystalloid and the fluorescently-labeled crystalloid are normal saline or lactated Ringer's solution; and the unmodified colloid and the fluorescently-labeled colloid are gelatin, hetastarch or dextran. In an alternative embodiment of the use of blood volume expander compositions, the unmodified crystalloid is normal saline or lactated Ringer's solution and the fluorescently-labeled tracer marker is a fluorescently labeled protein or colloid.
- In further illustrative embodiments of the use of blood volume expander compositions, the fluorescently-labeled protein, colloid or crystalloid is a dynamic molecule with a molecular weight of less than about 75 kDa, preferably about 40 Kda. Such dynamic molecules with a molecular weight of less than about 75 kDa include, for example normal saline, lactated Ringer's solution, gelatin, hetastarch, albumin and dextran.
- In one illustrative embodiment of the use of blood volume expander compositions, the unmodified colloid is Dextran 40, Dextran 70 or Dextran 75.
- In another illustrative embodiment of the use of blood volume expander compositions, the unmodified protein is albumin.
- In another illustrative embodiment of the use of blood volume expander compositions, the unmodified colloid is gelatin or hetastarch.
- In yet another illustrative embodiment of the use of blood volume expander compositions, the unmodified crystalloid is normal saline or lactated Ringer's solution.
- In further illustrative embodiments, the amount of fluorescently-labeled protein, colloid or crystalloid is present in an amount of from about 0.01% to about 10.0% by weight of unmodified protein, colloid or crystalloid, preferably 0.01% to about 1.0% by weight of unmodified protein, colloid or crystalloid, more preferably about 0.1% by weight of unmodified protein, colloid or crystalloid.
- In further illustrative embodiments of the use of blood volume expander compositions, the fluorescently-labeled protein or colloid is prepared by conjugating a protein or colloid with at least one fluorescent compound. Fluorescent compounds include, but are not limited to, Texas Red, fluorescein isothiocyanate (FITC) and 2-SulfhydroRhodamine (2SHR). In certain preferred embodiments, the fluorescent compound is fluorescein isothiocyanate (FITC).
- In yet other illustrative embodiments of the use of blood volume expander compositions, the patient is suffering from kidney disease, acute renal failure or chronic renal failure.
- In other illustrative embodiments of the use of blood volume expander compositions, the patient is suffering from blood loss due to trauma.
- According to the disclosure, the problems identified in the background as discussed above can be reduced or eliminated through the use of the plasma volume expanders, which incorporate a tracer compatible with the plasma volume expander, such as albumin “spiked” with a small amount of fluorescent albumin or dextran “spiked” with a small amount of a fluorescently-labeled dextran of similar, approximately identical, or identical molecular weight and dispersion characteristics. Accordingly, blood samples can be periodically or continuously taken from the patient, and the plasma volume concentration can be determined, thereby preventing an over-administration of the expander to the point where renal function can be impaired.
- Compositions also are disclosed that include unmodified dextrans as the plasma expander base combined with dextrans which have been labeled with a fluorescent marker added to the base. The labeled dextrans are compatible with the unmodified dextrans and can be used to measure their concentration within the plasma in a patient undergoing volume replacement therapy.
- In an illustrative embodiment, methods for the measurement, adjustment and maintenance of blood volume levels in a patient are accomplished by the use of a fluorescently-labeled detector molecule which is administered to the vascular system of a patient, followed by the administration of a blood volume expander having a different fluorescent characteristic. The first injected fluorescently-labeled molecule is used to make an initial determination of blood volume by taking a blood sample from the patient when equilibrium conditions have been established, and calculating the initial blood volume based on the fluorescent emission level of the sample. Following the initial measurement of blood volume, a blood volume expander containing tracer amounts of a differently fluorescent molecule is administered to the patient. Blood volumes can then be adjusted and maintained at the desired level for each individual patient. Blood loss or leakage from the patient can be monitored based on the rate of blood replenishments, or through the use of the novel blood volume expander compositions as described herein.
- In another illustrative embodiment, the fluorescently-labeled molecule is a large molecular weight dextran (>about 75 kDa) conjugated to one or more fluorescent markers. Preferably, the fluorescently-labeled dextran has a molecular weight of 150 kDA or more and is resident or “static” in the vascular system of the patient, meaning that it remains in the vascular system and is relatively impermeable, i.e. it does not penetrate the blood vessel walls, and is not metabolized, i.e. it is not immediately removed from the vascular space through a metabolic function of the body or an immunological response. The fluorescently-labeled dextran can be prepared by conjugating a fluorescent molecule and a macromolecule such as dextran in a conjugation reaction. Preferably, the fluorescent molecule is a compound selected from the group consisting of Texas Red, fluorescein isothiocyanate (FITC) and 2-SulfhydroRhodamine (2SHR), with 2SHR being especially preferred. Suitable techniques for preparing such molecules and deploying the molecules for measuring blood volume levels are disclosed in copending PCT patent application no. PCT/US2013/026277, the disclosure of which is incorporated by reference herein.
- In another illustrative embodiment, novel blood volume expander compositions are provided. Such compositions are prepared by supplementing an unmodified or standard dextran-based volume expander with a small amount of a fluorescently-labeled dextran (of a different fluorescent property than the “static” marker). The unmodified dextran volume expander is supplemented with from about 0.01% to about 10.0% by weight of fluorescently-labeled dextran, preferably about 0.01% to about 1.0% by weight, more preferably about 0.1% by weight. The fluorescently-labeled dextran is fully compatible with, and similar, nearly identical or identical in molecular weight and size dispersion to the unmodified dextran volume expander; preferably taken from the identical production lot number. After an initial plasma volume determination for the patient has been made, periodic or continual blood samples are taken to determine the change in plasma volume based on the level of fluorescent emissions in the sample using known analytical relationships as described herein.
- In yet another illustrative embodiment, the unmodified or standardized volume expander is a molecule having a molecular weight of 75 kDa or less. For example the unmodified or standardized volume expander can be albumin (66.5 kDa) or
Dextran - In a further illustrative embodiment, a method for measuring blood volume in a patient comprises the following steps. An initial determination of the blood volume of the patient is made by administering a fluorescently-labeled static molecule to the patient, a blood sample is taken when equilibrium conditions have been established, and the initial blood volume is calculated based on the fluorescent emission level of the sample. Following the initial measurement of blood volume, a blood volume expander is administered to the patient, and a second and possibly, further sets of blood samples are periodically taken once the volume expander has fully distributed and caused an increase in plasma volume. Alternatively, the blood volume can be continuously monitored using a blood line from the patient or through non-invasive techniques, such as with an external optical sensor.
- In one aspect of this embodiment, the patient is suffering from a medical condition such as kidney disease, acute or chronic renal failure, or acute blood loss.
- Other features and advantages of the present novel technology will be apparent from the following description.
- To understand the present invention, it will now be described by way of example with reference to the accompanying drawings in which:
-
FIG. 1 is a graph showing plasma volume (as determined using a “static” 150 kDa 2SHR dextran) over time for two exemplary volume expander mixtures in two different partially exsanguinated rats: a 40 kDa dextran spiked with a fluorescein-isothiocyanate (“FITC”) dextran tracer of 40 kDa dextran, and a 70 kDa dextran spiked with atracer FITC 70 kDa dextran. A third rat subjected to partial exsanguination and given identical saline volume but not treated with an expander was used as a control. -
FIG. 2 is a graph showing plasma volume (as determined by using a “static” 150 kDa 2SHR dextran) as a percent increase of initial volume over time for two exemplary volume expander mixtures in two different partially exsanguinated rats: a 40 kDa dextran spiked with atracer FITC 40 kDa dextran, and a 70 kDa dextran spiked with atracer FITC 70 kDa dextran. A third rat subject to partial exsanguinations and given identical saline volume but not treated with an expander was used as a control. The values are expressed as a % of the control changes in order to highlight the large plasma volume change that occurs with the expanders but not with the exsanguinated rat given identical saline volume but not an expander. The increase forrats -
FIG. 3 is a graph showing the decay in concentration over time for two exemplary volume expanders: a 40 kDa dextran spiked with atracer FITC 40 kDa dextran, and a 70 kDa dextran spiked with atracer FITC 70 kDa dextran. This graph illustrates that with this method it is possible to determine the concentration of the plasma expander by standard spectrophotometric methods and dilution principles. -
FIG. 4 is a graph showing the relationship between static marker fluorescence and plasma volume in the presence of two exemplary volume expanders: a 40 kDa dextran spiked with atracer FITC 40 kDa dextran, and a 70 kDa dextran spiked with atracer FITC 70 kDa dextran. - For the purposes of promoting an understanding of the principles of the invention, reference will be made to the embodiments illustrated in the drawings, and specific language will be used to describe the same. It will nevertheless be understood that these embodiments constitute no limitation as to the scope of the invention, with alterations and further modifications being permissible, and such further applications of the principles of the technology as illustrated therein, being contemplated as would normally occur to one skilled in the art to which the technology relates.
- Described herein are methods for determining, adjusting and maintaining plasma levels in a patient receiving a blood volume expander as part of a therapeutic program or treatment regime. Also described herein are improved blood volume expanders for directly measuring the amount of expander in a patient undergoing treatment. Also described herein are uses of the improved blood volume expanders for the manufacture of a medicament for measuring, adjusting and maintaining blood volume in a patient.
- A fluorescently-labeled dextran is incorporated in a dextran-based plasma volume expander (i.e. a small known amount of fluorescently-labeled dextran is mixed into a known amount of non-fluorescent dextran) to permit the direct measurement of the amount of expander by measuring the intensity of the signal generated by the fluorescent marker in the volume expander.
- Accordingly, and as may be used herein, the term “biological marker” or “biomarker” is intended to denote a molecular entity designed to be introduced into the vascular system of an animal, preferably a human subject, primarily to measure the function of an organ or vasculature of the animal. It is a biocompatible molecule formed as the conjugation product of one or more fluorescent molecules or dyes and a macromolecule.
- The terms “volume expander”, “blood volume expander”, and “plasma volume expander” are used synonymously herein and designate biocompatible compositions designed to restore vascular volume, stabilize circulatory haemodynamics, and maintain tissue perfusion. Typical blood volume expanders include saline, albumin and dextran, such as
Dextran 40,Dextran 70 and Dextran 75, where the numerical designations refer to the molecular weight of the dextran. - An “unmodified” or “standard” blood volume expander is a blood volume expander typically given to a patient in a clinical setting, and which does not include a labeled fluorescent component or molecule, or any other type of label or marker as a detection mechanism.
- The “blood volume” or “plasma volume” as used herein denotes the amount of plasma volume within the vascular space including arterial, venous and capillary spaces. The blood volume does not include the volume contributed by the blood cells, such as the red blood cells. The total blood volume is the blood volume and the volume contributed by the blood cells, which can be determined from the hematocrit or the packed cell volume.
- A “non-metabolized” molecule, or a molecule which is “not metabolized within the subject”, as used herein, is a molecule which is not significantly metabolized during the time in which the measurements are performed. Such molecules typically have a half life of 4 hours or greater in the vascular system of the subject.
- By “permeable to vessel walls” is meant a molecule that can cross vessel walls. Similarly, “impermeable to vessel walls” means that the molecule cannot cross the vessel walls either through a passive process or an active process.
- A “dynamic molecule” is a molecule of sufficiently low molecular mass to permeate the blood vessel walls or the vasculature of a subject. These molecules are also cleared by the kidney via glomerular filtration with a decrease in clearance as molecular weight increases. Dynamic molecules are known in the art to have a molecular mass of less than about 75 kDa.
- A “static molecule” is a molecule of sufficiently high molecular mass to significantly limit its blood vessel wall permeability and metabolism. Static molecules or markers may reach a quasi-stable vascular concentration for a period of time, although such markers may ultimately be cleared from the vasculature. Static markers are known in the art to have a molecular mass greater than about 75 kDa, preferably about 150 kDa. Such markers can remain in the vasculature for a time period of between about 1 or 2 hours, up to 12 hours or longer, depending on the molecular mass of the marker and rate of metabolism of the marker.
- The term “fluorescently-labeled crystalloid” as used herein refers to adding a free, unconjugated fluorescent dye such as FITC into the solution.
- According to the disclosure, the blood volume of a patient can be conveniently measured, adjusted and maintained using the techniques and compositions described herein. An initial assessment of the patient's blood volume is conducted, and once the initial assessment is completed, any loss in blood can be supplemented by administering a blood volume expander to the patient. Blood volume can be measured directly by utilizing a static fluorescent molecule introduced into the vascular system of the subject by techniques such as disclosed, for instance, in published PCT application PCT/US2013/026277, filed Feb. 15, 2013, the disclosure of which is incorporated herein in its entirety by reference. This procedure, in general, involves the administration of a static marker suitable for the measurement of initial plasma levels in a subject. The static marker can be a fluorescently-labeled dextran having a molecular weight greater than about 75 kDa to about 500 kDA, and preferably about 150 kDa. The fluorescent moiety used to label the dextran can be any of a variety of fluorescent molecules having a fluorescent excitation wavelength and an emission wavelength.
- The fluorescent moiety is conjugated with the dextran in a conjugation reaction by covalent attachment. The fluorescent molecule can be a fluorescent dye marker such as a rhodamine dye. Suitable fluorescent molecules include, by way of example, Texas Red, fluorescein isothiocyanate (FITC) and 2-sulfurhodamine (2SHR), with 2SHR being preferred.
- The static marker is introduced into the subject by, for instance, intravenous injection, and a blood sample can be taken after about 20 to 30 minutes once the volume expander has fully distributed. The sample can be taken using an indwelling venous catheter or a measurement can be made after about 20 to 30 minutes using a non-invasive sensor, such as a non-invasive optical sensor. The blood sample can be analyzed to establish the blood plasma level as described in PCT application no. PCT/US2013/026277.
- The use of fluorescently-labeled molecules to evaluate the physical condition of a subject by introducing the molecule into the vascular system of a subject has been disclosed. Suitable methods and materials can be found in U.S. patent application Ser. No. 12/425,827, filed Apr. 17, 2009 and U.S. patent application Ser. No. 12/946,471, filed Nov. 15, 2010, the respective disclosures of which are incorporated herein in their entirety by reference thereto.
- In general, according to the foregoing methods, a fluorescently-labeled macromolecule is introduced into the vascular system of a subject, such as by intravenous injection. Once equilibrium has been reached, blood samples can be periodically withdrawn, every 10 to 20 minutes for example, and the samples are analyzed for fluorescence in a medium formed from the sample, a buffering solution and an anionic surfactant. The analysis is conducted using a light source to activate the fluorescent molecule, and a light detector is used to measure and quantify the intensity of the fluorescent signal generated by the activated molecule. The biometric parameter under evaluation (blood volume) can be efficiently determined by comparing the values obtained from the samples of the subject with samples from a known source.
- The blood volume expander can be any of a variety of blood volume expanders typically used by a clinician. Suitable blood volume expanders include, for example, saline, albumin and dextran. In a typical clinical environment, the blood volume expander is administered to a subject in order to adjust and maintain the subject's blood volume at a predetermined level. Loss of blood typically occurs as a result of the treatment of the patient for a medical condition wherein blood loss is a significant factor or result. These conditions include severe trauma due to external injuries, and chronic renal disease and/or failure.
- The preferred blood volume expander is an unmodified or standard dextran solution, such as
Dextran 40,Dextran 70 or Dextran 75. The blood volume expander is “doped” or supplemented with a relatively small amount of a fluorescently-labeled dextran, typically from about 0.01% to about 10.0% by weight, preferably from about 0.01% to about 1.0% by weight, more preferably about 0.1% by weight. The blood volume expander itself is typically an aqueous solution of dextran on the order of 5% or 6% of dextran by weight. - The fluorescently labeled dextran can advantageously have about the same, near identical or identical molecular weight as the unmodified dextran. As noted, a dynamic molecule has a sufficiently low molecular weight to penetrate the blood vessel walls or vasculature of the patient. Therefore, the amount of the molecule in the vasculature will change over time, and this change can be recorded, measured, and correlated with a biological parameter of interest, such as the level of blood volume.
- The fluorescently-labeled dextran can be prepared by conjugating a fluorescent molecule with dextran using reaction techniques and conditions well known in the art. Typical fluorescent molecules which are suitable for conjugation include Texas Red, fluorescein isothiocyanate (FITC), and 2-SulfhydroRhodamine (2SHR), with fluorescein being preferred. The “doped” marker dextran in the expander must have a different fluorescent marker than the “static” 150 kDa dextran, which is preferably labeled with 2SHR.
- According to the disclosure, a blood sample can be taken from a patient on a continuous or periodic basis, and the level of the volume expander in the blood can be measured by recording and correlating the presence of the dynamic molecule in the blood sample with the blood volume. This technique can be used to provide an accurate real time measurement of blood volume.
- The methods and compositions described herein can be typically used in a clinic or hospital where the treatment of renal disease and renal failure are indicated.
- The invention is further illustrated by the examples provided below, which are directed to certain embodiments of the invention and are not intended to limit the full scope of the invention as set forth in the appended claims.
- A 13.6 mg dose of a 2SHR labeled dextran (150 kDa) is administered to a subject, and a blood sample is withdrawn after about 20 to 30 minutes to determine blood plasma volume using the procedure described in PCT application no. PCT/US2013/026277. This blood plasma level is recorded and used as a reference level for additional blood plasma volume measurements.
- Next, a standard dose of a
Dextran 40 orDextran 70 blood volume expander is administered to the subject with a small amount of a fluorescently-tagged dextran of approximately the same molecular weight added to the blood volume expander. For purposes of the example, a 30 gram solution ofDextran 40 orDextran 70 is formulated with about 30 mg of approximately the same molecular weight dextran conjugated to Fluorescein (FITC) (or about 0.1% of fluorescently-labeled dextran by weight of unmodified dextran). Blood plasma volume and fluorescent concentration (ug/mL) are recorded as a function of time forDextran 40 andDextran 70. The results are shown inFIGS. 1, 2 and 3 . -
FIG. 4 shows that when using thestatic 2SHR 150 kDa marker to measure plasma volume, an increase in plasma volume caused by the volume expanders results in a decrease in the fluorescence of the static marker as it becomes more diluted. - The compositions, uses thereof and methods described herein allow for the rapid determination of blood plasma levels. This facilitates the adjustment of patient fluid levels, such as the amount of blood plasma expander is required by the patient. This, in turn, can prevent renal damage due to a decrease in tubular flow as a result of renal blockage and stasis (the cessation of urinary excretion) which require adequate hydration as a treatment modality.
- While the invention has been illustrated and described in detail in the drawings and foregoing description, this is to be considered as illustrative and not restrictive in character. It is understood that one of ordinary skill in the art could readily make changes and modifications to the above-described embodiments and that it would be impractical to attempt to describe all such embodiment variations in the present specification. Accordingly, it is understood that all such changes and modifications that come within the spirit of the invention are desired to be protected.
Claims (9)
1.-10. (canceled)
11. A method for measuring blood volume in a patient comprising the steps of
administering a fluorescently-labeled static molecule to the vascular system of a patient, said static molecule having a first excitation wavelength and a first emission wavelength, said static molecule being non-metabolized within the patient,
obtaining a first blood sample from the patient or making a first non-invasive measurement of the blood of the patient after the static molecule has reached a fully distributed steady state concentration in the vascular system, and calculating the initial plasma volume based on the emission level in the sample,
periodically obtaining additional blood samples or non-invasive measurements from the patient,
measuring the blood volume in the patient.
12.-13. (canceled)
14. The method of claim 11 , wherein a series of additional blood samples are taken from the patient or a series of additional non-invasive measurements are made.
15. The method of claim 14 , wherein the additional blood samples are continuously taken through an indwelling venous catheter or the additional non-invasive measurements are continuously made using an optical sensor.
16. (canceled)
17. The method of claim 11 , wherein the fluorescently-labeled static molecule is a dextran with a molecular weight greater than about 75 kDa.
18. The method of claim 11 , wherein the fluorescently-labeled static molecule is a dextran with a molecular weight of 150kDa; preferably labeled with 2-SulfhydroRhodamine (2SHR).
19.-30. (canceled)
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US17/245,842 US20210379206A1 (en) | 2014-02-07 | 2021-04-30 | Compositions and methods for measuring and expanding blood volume |
Applications Claiming Priority (5)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US201461936981P | 2014-02-07 | 2014-02-07 | |
PCT/US2015/014845 WO2015120291A1 (en) | 2014-02-07 | 2015-02-06 | Compositions and methods for measuring and expanding blood volume |
US201615116650A | 2016-08-04 | 2016-08-04 | |
US16/363,068 US10994030B2 (en) | 2014-02-07 | 2019-03-25 | Compositions and methods for measuring and expanding blood volume |
US17/245,842 US20210379206A1 (en) | 2014-02-07 | 2021-04-30 | Compositions and methods for measuring and expanding blood volume |
Related Parent Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US16/363,068 Continuation US10994030B2 (en) | 2014-02-07 | 2019-03-25 | Compositions and methods for measuring and expanding blood volume |
Publications (1)
Publication Number | Publication Date |
---|---|
US20210379206A1 true US20210379206A1 (en) | 2021-12-09 |
Family
ID=53778482
Family Applications (3)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US15/116,650 Active US10279052B2 (en) | 2014-02-07 | 2015-02-06 | Compositions and methods for measuring and expanding blood volume |
US16/363,068 Active US10994030B2 (en) | 2014-02-07 | 2019-03-25 | Compositions and methods for measuring and expanding blood volume |
US17/245,842 Abandoned US20210379206A1 (en) | 2014-02-07 | 2021-04-30 | Compositions and methods for measuring and expanding blood volume |
Family Applications Before (2)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US15/116,650 Active US10279052B2 (en) | 2014-02-07 | 2015-02-06 | Compositions and methods for measuring and expanding blood volume |
US16/363,068 Active US10994030B2 (en) | 2014-02-07 | 2019-03-25 | Compositions and methods for measuring and expanding blood volume |
Country Status (3)
Country | Link |
---|---|
US (3) | US10279052B2 (en) |
EP (1) | EP3102217A4 (en) |
WO (1) | WO2015120291A1 (en) |
Families Citing this family (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP3102217A4 (en) * | 2014-02-07 | 2017-11-01 | Pharmacophotonics, Inc. D/B/A Fast Biomedical | Compositions and methods for measuring and expanding blood volume |
WO2023039129A1 (en) * | 2021-09-10 | 2023-03-16 | Pharmacophotonics, Inc. | Method and apparatus for monitoring plasma volume |
Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20120276014A1 (en) * | 2009-04-30 | 2012-11-01 | Pharmacophotonics, Inc. | Measurement of body fluid volumes |
US10279052B2 (en) * | 2014-02-07 | 2019-05-07 | Pharmacophotonics, Inc. | Compositions and methods for measuring and expanding blood volume |
Family Cites Families (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
AU705225B2 (en) * | 1995-03-23 | 1999-05-20 | Biopure Corporation | Stable polymerized hemoglobin blood substitute |
CA2279302A1 (en) * | 1997-02-05 | 1998-08-13 | University Of Wales College Of Medicine | Measurement of plasma volume |
US7037895B2 (en) * | 2001-03-27 | 2006-05-02 | Medical College Of Ohio | Albumin-based colloid composition and method of use in treating hypovolemia and multiorgan dysfunction |
US20090285761A1 (en) * | 2008-04-18 | 2009-11-19 | Pharmacophotonics, Llc D/B/A Fast Diagnostics | Renal Function Analysis Method and Apparatus |
-
2015
- 2015-02-06 EP EP15746505.5A patent/EP3102217A4/en active Pending
- 2015-02-06 WO PCT/US2015/014845 patent/WO2015120291A1/en active Application Filing
- 2015-02-06 US US15/116,650 patent/US10279052B2/en active Active
-
2019
- 2019-03-25 US US16/363,068 patent/US10994030B2/en active Active
-
2021
- 2021-04-30 US US17/245,842 patent/US20210379206A1/en not_active Abandoned
Patent Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20120276014A1 (en) * | 2009-04-30 | 2012-11-01 | Pharmacophotonics, Inc. | Measurement of body fluid volumes |
US10279052B2 (en) * | 2014-02-07 | 2019-05-07 | Pharmacophotonics, Inc. | Compositions and methods for measuring and expanding blood volume |
Also Published As
Publication number | Publication date |
---|---|
US10279052B2 (en) | 2019-05-07 |
US10994030B2 (en) | 2021-05-04 |
US20200000941A1 (en) | 2020-01-02 |
US20160346407A1 (en) | 2016-12-01 |
EP3102217A4 (en) | 2017-11-01 |
EP3102217A1 (en) | 2016-12-14 |
WO2015120291A1 (en) | 2015-08-13 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
US20210379206A1 (en) | Compositions and methods for measuring and expanding blood volume | |
Jacob et al. | Technical and physiological background of plasma volume measurement with indocyanine green: a clarification of misunderstandings | |
Abdelkader et al. | Renal oxygenation in acute renal ischemia-reperfusion injury | |
Merkel et al. | Effect of somatostatin on splanchnic hemodynamics in patients with liver cirrhosis and portal hypertension | |
Wang et al. | Rapid diagnosis and quantification of acute kidney injury using fluorescent ratio-metric determination of glomerular filtration rate in the rat | |
Proulx et al. | Non-invasive dynamic near-infrared imaging and quantification of vascular leakage in vivo | |
JP2011521899A (en) | Method and apparatus for analyzing renal function | |
EP2429588B1 (en) | Measurement of body fluid volumes | |
Molitoris | Rethinking CKD evaluation: should we be quantifying basal or stimulated GFR to maximize precision and sensitivity? | |
JP2020163170A (en) | Composition and method for monitoring biometric indicator | |
Allen et al. | Non‐invasive measurement of retinal permeability in a diabetic rat model | |
Morelle et al. | Quantification of osmotic water transport in vivo using fluorescent albumin | |
Baulig et al. | Cardiac output measurement by pulse dye densitometry in cardiac surgery | |
Maron | Differential effects of histamine on protein permeability in dog lung and forelimb | |
Qi et al. | Measurement of glomerular filtration rate in conscious mice | |
Heltne et al. | Determination of plasma volume in anaesthetized piglets using the carbon monoxide (CO) method | |
US6355624B1 (en) | Measurement of plasma volume | |
US20140193343A1 (en) | Measurement of body fluid volumes | |
Park et al. | Noninvasive hemoglobin monitoring for maintaining hemoglobin concentration within the target range during major noncardiac surgery: A randomized controlled trial | |
Rose et al. | Repeatability of measurements of the initial distribution volume of glucose in haemodynamically stable patients | |
RU2776412C2 (en) | CONTRAST COMPOSITION FOR MAGNETIC RESONANCE IMAGING AND ANGIOGRAPHY BASED ON Mn-DCTA | |
WO2015138702A1 (en) | Improved measurement of body fluid volumes | |
A Molitoris et al. | Quantifying glomerular filtration rates: kidney function analysis method and apparatus | |
JP2022504413A (en) | Methods and devices for determining gap volume | |
Mayerson | Orthostatic circulatory failure (" gravity shock") in the dog |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
STPP | Information on status: patent application and granting procedure in general |
Free format text: DOCKETED NEW CASE - READY FOR EXAMINATION |
|
STPP | Information on status: patent application and granting procedure in general |
Free format text: NON FINAL ACTION MAILED |
|
STCB | Information on status: application discontinuation |
Free format text: ABANDONED -- FAILURE TO RESPOND TO AN OFFICE ACTION |