A Model of Human Microvascular Exchange

Xie, S.L.; Reed, Rolf K.; Bowen, Bruce D.; Bert, Joel L.

doi:10.1006/mvre.1995.1012

Cited by 31 publications

(20 citation statements)

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“…Mathematically modeling the dynamics of interstitial fluid balance has had a long history, (7,8,11,30,33,34,64,79) and resulted in concepts such as an edema "safety factor" that has played a significant role in our current understanding of edema formation (31). Typically, these approaches focused solely on hemodilution or hemorrhage, and the role of vascular permeability.…”

Section: Discussionmentioning

confidence: 99%

“…4) into the equations that must be solved. To deal with these complications, investigators typically develop detailed mathematical models requiring numerical solutions (7,8,11,33,34,64,79). Because results cannot be expressed analytically (i.e., by an algebraic formula), they must be expressed as separate plots of fluid volume as a function of any one of a long list of parameters and variables: microvascular pressure, plasma colloid osmotic pressure, water permeability, interstitial compliance, effective lymphatic resistance, and venous pressure.…”

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confidence: 99%

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Edemagenic gain and interstitial fluid volume regulation

Dongaonkar

Quick²,

Stewart³

et al. 2008

American Journal of Physiology-Regulatory, Integrative and Comp

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Under physiological conditions, interstitial fluid volume is tightly regulated by balancing microvascular filtration and lymphatic return to the central venous circulation. Even though microvascular filtration and lymphatic return are governed by conservation of mass, their interaction can result in exceedingly complex behavior. Without making simplifying assumptions, investigators must solve the fluid balance equations numerically, which limits the generality of the results. We thus made critical simplifying assumptions to develop a simple solution to the standard fluid balance equations that is expressed as an algebraic formula. Using a classical approach to describe systems with negative feedback, we formulated our solution as a "gain" relating the change in interstitial fluid volume to a change in effective microvascular driving pressure. The resulting "edemagenic gain" is a function of microvascular filtration coefficient (K(f)), effective lymphatic resistance (R(L)), and interstitial compliance (C). This formulation suggests two types of gain: "multivariate" dependent on C, R(L), and K(f), and "compliance-dominated" approximately equal to C. The latter forms a basis of a novel method to estimate C without measuring interstitial fluid pressure. Data from ovine experiments illustrate how edemagenic gain is altered with pulmonary edema induced by venous hypertension, histamine, and endotoxin. Reformulation of the classical equations governing fluid balance in terms of edemagenic gain thus yields new insight into the factors affecting an organ's susceptibility to edema.

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Section: Discussionmentioning

confidence: 99%

mentioning

confidence: 99%

Edemagenic gain and interstitial fluid volume regulation

Dongaonkar

Quick²,

Stewart³

et al. 2008

American Journal of Physiology-Regulatory, Integrative and Comp

View full text Add to dashboard Cite

show abstract

“…1 combines ideas and equations from two previous models of the cardiovascular hemodynamics (Randall, 1986;Mason, 1989) and fluid exchange in the microcirculation (Xie, 1995). (Randall, 1986;Mason, 1989;Xie, 1995) The flow through the left and right heart, i.e. the cardiac output, is described by the following empirically derived equations:…”

Section: Physiological Modeling Of the Cardiac Function In Septic Patmentioning

confidence: 99%

“…Subscripts p and s denote pulmonary and systemic, v and a denote veins and arteries. The compliance and resistance parameters were taken from (Xie, 1995;Gyenge et al, 1999).…”

Section: Physiological Modeling Of the Cardiac Function In Septic Patmentioning

confidence: 99%

“…A constant urine output was also included in the model. The Cardiovascular System (CVS) model is extended with an additional compartment describing the transport and distribution of fluid and plasma proteins between the circulation and the interstitial space (Xie, 1995;Gyenge et al, 1999). In the microcirculation, fluid and protein balance is maintained by hydrostatic and oncotic pressures existing on either sides of the capillary barrier according to Starling's equation which described the rate of fluid filtration from the circulation to the interstitial space (Gyenge et al, 1999;Klabunde, 2004).…”

Section: Physiological Modeling Of the Cardiac Function In Septic Patmentioning

confidence: 99%

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