Hypothermia and blood flow behavior

Schmid‐Schönbein, H.; Klose, Holger; Volger, E; Weiss, J

doi:10.1007/bf01851023

Cited by 11 publications

(3 citation statements)

References 12 publications

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“…The dynamic viscosity of plasma is also strongly dependent on temperature. It varies from μ = 3.1 mPa s at 4–5°C to μ = 1.25 mPa at 35–37°C [ 43 , 44 ]. Plasma is a Newtonian liquid, its viscosity is independent of shear rate [ 45 ].…”

Section: Resultsmentioning

confidence: 99%

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Effects of Aggregation on Blood Sedimentation and Conductivity

Zhbanov

Yang

2015

PLoS ONE

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The erythrocyte sedimentation rate (ESR) test has been used for over a century. The Westergren method is routinely used in a variety of clinics. However, the mechanism of erythrocyte sedimentation remains unclear, and the 60 min required for the test seems excessive. We investigated the effects of cell aggregation during blood sedimentation and electrical conductivity at different hematocrits. A sample of blood was drop cast into a small chamber with two planar electrodes placed on the bottom. The measured blood conductivity increased slightly during the first minute and decreased thereafter. We explored various methods of enhancing or retarding the erythrocyte aggregation. Using experimental measurements and theoretical calculations, we show that the initial increase in blood conductivity was indeed caused by aggregation, while the subsequent decrease in conductivity resulted from the deposition of erythrocytes. We present a method for calculating blood conductivity based on effective medium theory. Erythrocytes are modeled as conducting spheroids surrounded by a thin insulating membrane. A digital camera was used to investigate the erythrocyte sedimentation behavior and the distribution of the cell volume fraction in a capillary tube. Experimental observations and theoretical estimations of the settling velocity are provided. We experimentally demonstrate that the disaggregated cells settle much slower than the aggregated cells. We show that our method of measuring the electrical conductivity credibly reflected the ESR. The method was very sensitive to the initial stage of aggregation and sedimentation, while the sedimentation curve for the Westergren ESR test has a very mild slope in the initial time. We tested our method for rapid estimation of the Westergren ESR. We show a correlation between our method of measuring changes in blood conductivity and standard Westergren ESR method. In the future, our method could be examined as a potential means of accelerating ESR tests in clinical practice.

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Section: Resultsmentioning

confidence: 99%

“…We calculated the settling velocities of erythrocytes during sedimentation at different HCT values using Eqs 18 and 19 ( Table 5 ). Here, we assume that the dynamic viscosity of plasma is μ = 1.65 mPa s at room temperature (24°C), as follows from an interpolation of the available experimental data [ 43 , 44 ].…”

Section: Resultsmentioning

confidence: 99%

Effects of Aggregation on Blood Sedimentation and Conductivity

Zhbanov

Yang

2015

PLoS ONE

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“…Die eigenen Versuche haben jedoch gezeigt, dal3 bei Anwendung kristalloider und kolloidaler Perfusionsl6sungen die Perfusionsraten w~ihrend der Kt~hlung successiv erh6ht werden k0nnen, so dal3 wesentlich h6here Bypassraten als in der Literatur angegeben, resultieren [1,19,20,29,37,42,57]. Die starke Blutverdt~nnung und die Verbesserung der rheologischen Eigenschaften des Perfusates wirken daher der ffir Hypothermie typischen Umverteilung der Gesamtdurchstr6mung mit regionaler Temperaturdissoziation und Gefahr der Hypoxie [6,8,13,52] entgegen. Die starke Blutverdt~nnung und die Verbesserung der rheologischen Eigenschaften des Perfusates wirken daher der ffir Hypothermie typischen Umverteilung der Gesamtdurchstr6mung mit regionaler Temperaturdissoziation und Gefahr der Hypoxie [6,8,13,52] entgegen.…”

Section: Methodik Des Totalen Blutaustauschesunclassified

Hypothermer Kreislaufstillstand nach totalem Blutaustausch beim Hund

et al. 1978

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Total body washout (hct less than 1%) in hypothermia was performed in 31 dogs using either a crystalloidal or a colloidal perfusate. Blood exchange and cooling was achieved by means of partial bypass and heat exchanger. Short lasting blood exchange for crystalloids without cardiac arrest resulted in 66% survival of the animals. When in addition circulatory arrest was established for 30 min at 14 degrees C oesophageal temperature blood exchange for crystalloids was not tolerated. All four animals of this group died within 19 hours presenting massive interstitial edema. Replacement of the crystalloidal perfusate by a colloidal solution (2.5 g% Dextran 60 at Ringer's Lactate) and establishing circulatory for 30 or 60 min resulted in survival rates of 71% and 50% respectively. The use of the colloidal perfusate effectively prevented edema formation. Death could not be correlated with the parameters controlled.

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Influence of temperature on the optimal hematocrit of the bullfrog (Rana catesbeiana)

Weathers

1976

J Comp Physiol B

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Hypothermia and blood flow behavior

Cited by 11 publications

References 12 publications

Effects of Aggregation on Blood Sedimentation and Conductivity

Effects of Aggregation on Blood Sedimentation and Conductivity

Hypothermer Kreislaufstillstand nach totalem Blutaustausch beim Hund

Influence of temperature on the optimal hematocrit of the bullfrog (Rana catesbeiana)

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