Transvascular fluid shifts accompanying short bodily activity in the alert rat and their relation to arterial pressure

Aziz, O.; Sommer, Ewa

doi:10.1007/bf02005343

Cited by 6 publications

(15 citation statements)

References 14 publications

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“…As mentioned, the method was developed in order to substantiate the results of experiments in which very rapid transvascular fluid movements were demonstrated essentially by blood conductometry (3,4,5). For the most part this has successfully been done qualitatively in the present experiments.…”

Section: Discussionmentioning

confidence: 93%

“…Due to the inertia of the system, very small and rapid changes (see small negative peaks as initial reaction to "activation" in the portal vein hct curve of Fig. 3A, described in detail in [3]) are not reproduced in the refractometric curves. However, the equivalent reaction to the rather large doses of noradrenalin (Fig.…”

Section: Discussionmentioning

confidence: 95%

“…Essentially the method of continuous plasmapheresis from streaming blood and continuous measurement of plasma protein will be described here, the experimental procedures having been presented in earlier papers (1,3).…”

Section: Methodsmentioning

confidence: 99%

“…In previous papers (3,4,5), conductometrically measured hematocrit (hct) was monitored as an indicator of fluid content of blood flowing in various parts of the circulatory system of the rat. The assumption of a correlation between hct changes and transvascular fluid movements was substantiated by occasional determination of both hct and total plasma protein in situations where sufficiently large and sustained changes took place for reliable measurements.…”

Section: Introductionmentioning

confidence: 99%

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Continuous simultaneous measurement of plasma protein concentration and hematocrit in the alert rat. A short preliminary report

1985

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A method for continuous plasmapheresis and refractometric determination of the protein concentration of blood circulating in the vascular system of the unanesthetized rat is presented. The method is applied to demonstrate very rapid transvascular fluid exchange during physical activity of the animal, noradrenalin infusions and hemorrhage. Changes of protein concentration are compared with concomitant changes of hematocrit in the hepatic portal vein and the v. cava inferior. Though both parameters invariably change in a parallel fashion, relative variations of protein concentration fall short of hot variations by 50%.

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Section: Discussionmentioning

confidence: 93%

Section: Discussionmentioning

confidence: 95%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Continuous simultaneous measurement of plasma protein concentration and hematocrit in the alert rat. A short preliminary report

1985

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“…As in previous papers (1,2), in which it was shown that very rapid changes of protein concentration accompany hematoerit changes in acute hemorrhage, changes of plasma volume were followed by continuous registration of large vein hematocrit by means of conductometry while producing in the present experiments pulsatile changes of blood volume of various fixed amplitudes and period lengths, thus varying blood withdrawal rates within wide limits. Beside hct, arterial pressure and heart rate were determined for assessment of their influences on fluid exchange between the two compartments of extracellular space.…”

Section: Introductionmentioning

confidence: 81%

Volume control during periodic changes of blood volume in the alert rat

Aziz¹,

Sommer²

1984

Basic Res Cardiol

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Blood (3.4-13.5% of blood volume) was pumped in and out of the circulation of rats at different rates and period lengths during continuous measurements of blood conductivity (reciprocally related to hematocrit) and arterial pressure. Hct followed the same zig-zag course as the induced changes of blood volume in every case, indicating that fluid shifts (delta v) between interstitium and intravascular space closely follow blood volume changes. As the hct increase during reinfusion was not as great as the preceding decrease, hct dropped continuously during the 20-90 minutes of experimentation, so that a final volume increase (delta v) by about 4% was calculated, which was confirmed by a corresponding decrease of plasma protein concentration. Both final delta v and delta v during periodic volume change (delta % B.V.) were greater when arterial pressure dropped. delta v was directly related to delta % B.V. but not to its rate of change. Heart rate dropped slightly at the end of the reinfusion periods, whereas it rose to control at the end of the withdrawal periods. The results were regarded as evidence of blood volume regulation proportional to the absolute volume of blood lost in non-hypotensive hemorrhage.

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The influence of arterial pressure changes on blood volume replacement after acute hemorrhage in the alert rat

Aziz

Sommer

1983

Basic Res Cardiol

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The fluid content of circulating blood was followed continuously by conductometric measurement of large vein hematocrit in the alert rat. Arterial pressure was registered simultaneously. 2.5-23% of the determined blood volume was withdrawn rapidly and the changes of fluid content (delta v) calculated. Determinations of plasma protein showed that calculated delta v(delta vapp) may exceed true delta v due to transvascular fluid inflow by maximally 38%. A very fast phase of fluid inflow into the circulation (delta vfapp, within 1 min) was observed at the beginning, followed by a slow phase (delta vsapp), the magnitude of both being proportional to the concomitant arterial pressure drop (delta p). At delta p = 0, delta vfapp was 20% of the volume of blood withdrawn, total replacement (delta vfapp + delta vsapp = volume withdrawn) being complete in 60 min. At delta p = -20 mm Hg the figures were 40% and 20 min, respectively. Experiments on splenectomized animals showed essentially the same relations, excepting that delta vsapp may have been underestimated in normal rats. An arterial pressure rise after hemorrhage may attenuate complete replacement. The results are discussed in terms of capillary fluid conductivity. Thus CFC may be in the order of 0.029 ml/min x mm Hg x 100 g.

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Transvascular fluid shifts accompanying short bodily activity in the alert rat and their relation to arterial pressure

Cited by 6 publications

References 14 publications

Continuous simultaneous measurement of plasma protein concentration and hematocrit in the alert rat. A short preliminary report

Continuous simultaneous measurement of plasma protein concentration and hematocrit in the alert rat. A short preliminary report

Volume control during periodic changes of blood volume in the alert rat

The influence of arterial pressure changes on blood volume replacement after acute hemorrhage in the alert rat

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