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The following message was posted to: PharmPK
I would like to know how we can measure the extracellular water volume
with inulin or sinistrin.
Thanks in advnce.
M. Sánchez
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The following message was posted to: PharmPK
The following paper gives references for assays to measure inulin
(extracellular fluid space), indocyanine green (intravascular volume),
and antipyrine (total body water).
dhanesh
J Pharmacol Exp Ther. 1996 Sep;278(3):1050-7. Related Articles, Links
Recirculatory pharmacokinetic models of markers of blood, extracellular
fluid and total body water administered concomitantly.
Krejcie TC, Henthorn TK, Niemann CU, Klein C, Gupta DK, Gentry WB,
Shanks CA, Avram MJ.
Northwestern University Medical School, Department of Anesthesiology,
Chicago, Illinois, USA.
Pharmacokinetic models were developed to describe the disposition of
markers of extracellular fluid (inulin) and total body water
(antipyrine) from the moment of injection to incorporate the
intravascular mixing component, determined by a marker of intravascular
space (indocyanine green, ICG). The simultaneous dispositions of these
markers were characterized in four halothane-anesthetized dogs. After
injection of ICG, [14C]-inulin, and antipyrine into the right atrium,
femoral arterial blood samples were collected every 3 sec for 1 min and
less frequently to 20 min for ICG and to 360 min for inulin and
antipyrine. ICG and antipyrine concentrations were measured by
high-performance liquid chromatography and [14C]-inulin concentrations
were measured by liquid scintillation counting. The marker
concentration histories were characterized completely by fully
identifiable recirculatory compartmental models. Because neither ICG
nor inulin distribute beyond intravascular space before recirculation,
their first-pass data were modelled simultaneously to improve
confidence in central circulation model parameters. This central
circulation model included an estimate of cardiac output that was
retained in the recirculatory models of all markers. Three tissue
compartments were identified for antipyrine, a lipid soluble marker
that equilibrates with tissue (including the lung) and estimates total
body water and tissue blood flow. The hydrophilic marker, inulin,
diffuses into interstitial fluid so slowly that only two extravascular
compartments were identified. These models may be used to determine how
cardiac output and its distribution, pulmonary drug uptake, and
nondistributive blood flow contribute to variability in patient
response to drugs with a rapid onset of effect.
PMID: 8819485 [PubMed - indexed for MEDLINE]
Dhanesh K. Gupta, M.D.
Assistant Professor
Division of Neuroanesthesia
Department of Anesthesiology
University of Utah SOM
30 N 1900 E Room 3C-444
TEL: (801) 581-6393 X313
PGR:(801) 249-1296
Salt Lake City, UT 84132
TEL: 801-581-6393
FAX: 801-581-6397
E-mail: Dhanesh.Gupta.-a-.hsc.utah.edu
E-mail: guptad.aaa.runbox.com
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