The effect of posture on the capillary filtration rate in the human forearm

1970 ◽  
Vol 48 (6) ◽  
pp. 405-414 ◽  
Author(s):  
P. D. Newberry ◽  
J. M. McDonald ◽  
E. R. Rowe
Keyword(s):  
Filtration Rate ◽  
Room Temperature ◽  
Venous Pressure ◽  
Filtration Coefficient ◽  
Left Forearm ◽  
Capillary Filtration ◽  
Capillary Filtration Coefficient ◽  
Human Forearm ◽  
Capillary Resistance ◽  
Male Subjects

A water-filled plethysmograph of a new design was used to measure the capillary filtration rate in the left forearm of each of six male subjects at a room temperature of 27 °C, in the supine and the seated positions. The adoption of the seated position resulted in a decrease of the capillary filtration rate by an average of 0.050 ± 0.015 S.E. ml/min∙100 ml (p < 0.02) and in an increase of the average threshold venous pressure for capillary filtration from 14 to 26 mm Hg (p < 0.01). This change was associated with an increase in the post-capillary resistance. Adoption of the seated position caused no significant change in the capillary filtration coefficient.

Fetal whole-body interstitial compliance, vascular compliance, and capillary filtration coefficient

1984 ◽  
Vol 247 (5) ◽  
pp. R800-R805 ◽  
Author(s):  
R. A. Brace ◽  
P. S. Gold
Keyword(s):  
Venous Pressure ◽  
Isotonic Saline ◽  
Optimization Techniques ◽  
Filtration Coefficient ◽  
Whole Body ◽  
Fetal Sheep ◽  
Mean Values ◽  
Capillary Filtration ◽  
Vascular Compliance ◽  
Capillary Filtration Coefficient

Fluid movements across the capillary wall were studied in chronically catheterized, near-term fetal sheep. We hemorrhaged 15 fetuses and infused isotonic saline in seven fetuses. The average experimental changes in arterial pressure, venous pressure, and blood volume were then analyzed by using mathematical modeling and parameter optimization techniques to estimate mean values for the average whole-body interstitial and vascular compliances of the fetus and for the average whole-body fetal capillary filtration coefficient. After fetal hemorrhage, interstitial compliance averaged 45 ml X mmHg-1 X kg-1 of fetal weight and vascular compliance averaged 3.0 ml X mmHg-1 X kg-1, whereas the capillary filtration coefficient averaged 0.4 ml X min-1 X mmHg-1 X kg-1. For intravenous saline infusions, interstitial compliance averaged 45 ml X mmHg-1 X kg-1, and vascular compliance averaged 3.5 ml X mmHg-1 X kg-1, whereas the capillary filtration coefficient averaged 0.8 ml X min-1 X mmHg-1 X kg-1. These data suggest that the fetus has a high whole-body interstitial compliance and a high capillary filtration coefficient compared with the adult. In addition, it appears that the fetus has the ability to decrease its vascular compliance and capillary surface area after a fetal hemorrhage.

scholarly journals Comparative Study of Capillary Filtration Coefficient (Kfc) Determination by a Manual and Automatic Perfusion System. Step by Step Technique Review

2019 ◽  
pp. 901-908
Author(s):  
C.C. Bravo-Reyna ◽  
G. Torres-Villalobos ◽  
N. Aguilar-Blas ◽  
J. Frías-Guillén ◽  
J.R. Guerra-Mora
Keyword(s):  
Arterial Pressure ◽  
Pulmonary Arterial Pressure ◽  
Ischemia Reperfusion ◽  
Venous Pressure ◽  
Filtration Coefficient ◽  
Perfusion System ◽  
Gold Standard Method ◽  
Capillary Filtration ◽  
Capillary Filtration Coefficient ◽  
Pulmonary Arterial

The purpose of calculating the capillary filtration coefficient is to experimentally evaluate edema formation in models of pulmonary ischemia-reperfusion injury. For many years, the obtaining of this coefficient implies a series of manual maneuvers during ex-vivo reperfusion of pulmonary arterial pressure, venous pressure and weight, as well as the calculation of the Kfc formula. Through automation, the calculation of capillary filtration coefficient could be easier and more efficient. To describe an automatic method designed in our laboratory to calculating the capillary filtration coefficient and compare with traditional determination of capillary filtration coefficient as gold standard method. An automatic three valve perfusion system was constructed, commanded by a mastery module connected to a graphical user interface. To test its accuracy, cardiopulmonary blocks of Wistar rats were harvested and distributed in manual (n=8) and automated (n=8) capillary filtration coefficient determination groups. Physiological parameters as pulmonary arterial pressure, pulmonary venous pressure, weight and capillary filtration coefficient were obtained. Results: Capillary filtration coefficient, pulmonary arterial pressure, venous arterial pressure shown no statistical significance difference between the groups. The automated perfusion system for obtaining Kfc was standardized and validated, giving reliable results without biases and making the process more efficient in terms of time and personal staff.

The Pre- to Post-capillary Resistance Ratio in the Human Forearm

1971 ◽  
Vol 49 (8) ◽  
pp. 758-773
Author(s):  
P. D. Newberry ◽  
G. A. Hayman ◽  
S. Parsons
Keyword(s):  
Venous Pressure ◽  
Mean Value ◽  
Resistance Ratio ◽  
Capillary Filtration ◽  
Human Forearm ◽  
Brass Sheet ◽  
Capillary Resistance ◽  
The Mean ◽  
The Absolute ◽  
The Relationship

A plethysmograph made of two rubber bladders, enclosed in a sleeve of thin brass sheet, was used to measure capillary filtration rate [Formula: see text] in the forearms of five supine subjects at a room temperature of 27 ± 1 °C, at several plethysmograph pressures (pPL) between 0 and 25 mm Hg while venous pressure (pV) was held constant. We (Newberry et al. 1970) reported previously that in the same five subjects [Formula: see text] increased linearly with pV at a mean rate of 0.00357 ml/min∙100 ml∙mm Hg. [Formula: see text] decreased linearly with pPL in each subject (r varied from −0.81 to −0.99) at a mean rate of −0.00538 ml/min∙100 ml∙mm Hg. Compared as paired values the absolute values of these rates are significantly different (p < 0.02). It is shown that the pre- to post-capillary resistance ratio (rA:rV) can be determined from the relationship between the rates of change of [Formula: see text] with change of pV and pPL. The mean value of this ratio was 2:1 with a range from 1.03:1 to 3.5:1. It is likely that the absolute value of [Formula: see text]/ΔpPL is the capillary filtration coefficient.

Sympathetic stimulation and intestinal capillary fluid exchange

1984 ◽  
Vol 247 (3) ◽  
pp. G279-G283 ◽  
Author(s):  
D. N. Granger ◽  
J. A. Barrowman ◽  
S. L. Harper ◽  
P. R. Kvietys ◽  
R. J. Korthuis
Keyword(s):  
Capillary Pressure ◽  
Nerve Stimulation ◽  
Sympathetic Nerve ◽  
Filtration Rate ◽  
Lymph Flow ◽  
Filtration Coefficient ◽  
Fluid Exchange ◽  
Sympathetic Nerve Stimulation ◽  
Capillary Filtration ◽  
Capillary Filtration Coefficient

Sympathetic nerve stimulation is generally considered not to alter intestinal capillary pressure or filtration rate because of appropriate adjustments in the pre-to-postcapillary resistance ratio. To directly assess this possibility, we measured lymph flow, capillary pressure, capillary filtration coefficient, and the transcapillary oncotic pressure gradient in the cat small intestine. Measurements were taken under control conditions and during the steady-state phase of periarterial nerve stimulation, i.e., following completion of the escape phase. Venous outflow pressure was held constant (0 mmHg) during the entire experiment. Nerve stimulation resulted in a significant reduction of lymph flow (by 65%), capillary filtration coefficient (by 75%), and capillary pressure (by 15%). Interstitial fluid pressure, calculated from the measured parameters in the Starling equation, was also reduced (from -0.74 to -2.53 mmHg) by nerve stimulation. The results of this study indicate that intestinal capillary pressure and capillary filtration rate are not "autoregulated" during sympathetic nerve stimulation. Capillary derecruitment appears to be largely responsible for the dramatic reduction in filtration rate associated with adrenergic stimulation.

Pancreatic circulation: intrinsic regulation

1982 ◽  
Vol 242 (6) ◽  
pp. G596-G602
Author(s):  
P. R. Kvietys ◽  
J. M. McLendon ◽  
G. B. Bulkley ◽  
M. A. Perry ◽  
D. N. Granger
Keyword(s):  
Blood Flow ◽  
Arterial Pressure ◽  
Vascular Resistance ◽  
Venous Pressure ◽  
Filtration Coefficient ◽  
Pancreatic Blood Flow ◽  
Capillary Filtration ◽  
Pressure Elevation ◽  
Capillary Filtration Coefficient ◽  
Intrinsic Regulation

The purpose of the present study was to characterize the intrinsic mechanisms involved in the regulation of blood flow and oxygenation in the totally isolated, perfused canine pancreas. Arterial pressure, venous outflow pressure, blood flow, arteriovenous oxygen difference, and capillary filtration coefficient were measured during graded arterial pressure reductions and venous pressure elevation. Reductions in arterial pressure caused pancreatic blood flow and vascular resistance to decrease, whereas venous pressure elevation resulted in a decreased blood flow and increased vascular resistance. The reductions in blood flow produced by arterial and venous pressure alterations were associated with increases in oxygen extraction and capillary filtration coefficient. During the same pressure perturbations, oxygen uptake remained constant between blood flows of 40-100 ml.min-1.100 g-1, yet decreased progressively as blood flow was reduced below 40 ml.min-1.100 g-1. Arterial occlusion resulted in a postocclusive reactive hyperemia, the magnitude of which was related to the duration of occlusion. The findings of this study suggest that intrinsic regulation of pancreatic blood flow can be attributed to both metabolic and myogenic mechanisms. Resistance and exchange vessels both appear to play a role in the regulation of oxygen delivery to the pancreatic parenchyma.

Effect of ANP on circulating blood volume

1989 ◽  
Vol 257 (1) ◽  
pp. R127-R131 ◽  
Author(s):  
E. Sugimoto ◽  
K. Shigemi ◽  
T. Okuno ◽  
T. Yawata ◽  
T. Morimoto
Keyword(s):  
Blood Volume ◽  
Venous Pressure ◽  
Filtration Coefficient ◽  
Whole Body ◽  
Control Group ◽  
Peak Reduction ◽  
Circulating Blood Volume ◽  
Capillary Filtration ◽  
Control Value ◽  
Capillary Filtration Coefficient

The effects of rat atrial natriuretic peptide (rANP) on blood volume (BV) were determined by the continuous measurement of BV, mean arterial pressure (MAP), and central venous pressure (CVP). Immediately after a single-bolus injection of rANP-(1-28), 1 nmol/100 g body wt, in conscious rats, BV began to decrease. Peak reduction of -0.22 +/- 0.03 ml/100 g body wt was reached 14.5 min after the injection. Thereafter, BV levels returned gradually to -0.08 +/- 0.03 ml/100 g body wt compared with the control value. In volume expansion experiment, the nephrectomized, anesthetized rats were divided into two groups: the control group, with only a saline infusion, and the ANP group, with an infusion of saline with rANP (1 nmol/100 g body wt). In the ANP group, increases in BV were not as great, and recovery was threefold faster than that of the control group. In the ANP group, the recovery time of BV to the starting control levels was 8.5 min, and the time constant of recovery was 3.6 +/- 0.3 min-1. The control group times were 25 min and 11.5 +/- 0.8 min-1, respectively. The effective vascular compliances were approximately 2.8 ml.mmHg-1.kg body wt-1 in both groups, and the capillary filtration coefficient was 0.47 ml.mmHg-1.min-1.kg body wt-1 in the ANP group and 0.33 ml.mmHg-1.min-1.kg body wt-1 in the control group. Thus the whole body capillary filtration coefficient was 1.5-fold higher in the ANP group than in the control group. This suggests that ANP may increase the permeability of capillaries.

Autoregulation of intestinal capillary filtration rate

1982 ◽  
Vol 243 (6) ◽  
pp. G475-G483
Author(s):  
D. N. Granger ◽  
N. A. Mortillaro ◽  
M. A. Perry ◽  
P. R. Kvietys
Keyword(s):  
Arterial Pressure ◽  
Capillary Pressure ◽  
Filtration Rate ◽  
Pressure Range ◽  
Fluid Pressure ◽  
Lymph Flow ◽  
Filtration Coefficient ◽  
Capillary Filtration ◽  
Capillary Filtration Coefficient ◽  
Flow Capillary

To determine whether intestinal capillary filtration rate, capillary pressure, or both are autoregulated in the cat ileum, the following parameters were measured under isovolumetric conditions: lymph flow, capillary pressure, capillary filtration coefficient, and lymph and plasma oncotic pressures. Superior mesenteric arterial pressure was reduced in 25-mmHg steps from 125 to 25 mmHg. As arterial pressure was reduced, lymph flow, capillary pressure, and the transcapillary oncotic pressure gradient decreased while the capillary filtration coefficient increased. Over the arterial pressure range of 75-125 mmHg, capillary pressure decreased in a fashion expected from a rigid system; however, capillary pressure was slightly autoregulated at lower arterial pressures. Lymph flow fell proportionately more than capillary pressure over the entire arterial pressure range. The results of this study indicate that intestinal capillary pressure and capillary filtration rate are poorly autoregulated in the cat when arterial pressure is reduced. Changes in interstitial fluid pressure play a major role in preventing interstitial dehydration in the cat ileum when arterial pressure is reduced.

Effects of Hypoxia on Capillary Filtration Coefficient and Isovolumetric Venous Pressure

1995 ◽  
Vol 89 (s33) ◽  
pp. 29P-29P
Author(s):  
DM Lewis ◽  
H Hoare ◽  
AR Bradwell ◽  
AC Shore ◽  
M Beaman ◽  
...  
Keyword(s):  
Venous Pressure ◽  
Filtration Coefficient ◽  
Capillary Filtration ◽  
Capillary Filtration Coefficient

Evaluation of Starling forces in the equine digit

1988 ◽  
Vol 64 (4) ◽  
pp. 1580-1583 ◽  
Author(s):  
D. Allen ◽  
R. J. Korthuis ◽  
S. Clark
Keyword(s):  
Capillary Pressure ◽  
Interstitial Fluid ◽  
Venous Pressure ◽  
Fluid Pressure ◽  
Calculated Data ◽  
Filtration Coefficient ◽  
Fluid Exchange ◽  
Tissue Pressure ◽  
Capillary Filtration ◽  
Capillary Filtration Coefficient

A pump-perfused extracorporeal digital preparation was used to evaluate blood flow, arterial pressure, venous pressure, isogravimetric capillary filtration coefficient, capillary pressure, and vascular compliance in six normal horses. From these data, pre- and postcapillary resistances and pre- and postcapillary resistance ratios were determined. Vascular and tissue oncotic pressures were estimated from plasma and lymph protein concentrations, respectively. By use of the collected and calculated data, tissue pressure in the digit was calculated using the Starling equation. In the isolated equine digit, isogravimetric capillary pressure averaged 36.7 mmHg, plasma and lymph oncotic pressures averaged aged 19.12 and 6.6 mmHg, respectively, interstitial fluid pressure averaged 25.6 mmHg, and the capillary filtration coefficient averaged 0.0013 ml.min-1.mm-1.100 g-1. Our results indicate that digital capillary pressure in the laterally recumbent horse is much higher than in analogous tissues in other species such as dog and human. However, the potential edemagenic effects of this high digital capillary pressure are opposed by at least two mechanisms: 1) a high tissue pressure and 2) a low microvascular surface area for fluid exchange and/or a low microvascular permeability to filtered fluid.

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