Pulmonary interstitial resistance

Lai-Fook, S. J.; Conhaim, Robert L.

doi:10.1007/bf02364052

Cited by 3 publications

(1 citation statement)

References 49 publications

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“…Movement of a visous fluid is associated with a pressure drop in the direction of flow. Lai-Fook has argued that the pressure distribution in the pulmonary pleura depends on pleural fluid motion (2,14,15). However, in the current analysis we are not so much concerned with pressure gradients due to fluid motion, but rather, the reverse: the driving pressures which give rise to fluid motion.…”

Section: Appendix a Theoretical Considerationsmentioning

confidence: 99%

Nonuniform distribution of normal pericardial fluid

1990

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It has been suggested that pericardial fluid functions as a lubricant rather than a means of transmitting pericardial pressure from one region of the heart to another. Since the functional behavior of pericardial fluid depends on fluid thickness, we measured pericardial volume and fluid distribution. In seven animals, we found that the normal canine pericardium contains 0.25 +/- 0.15 ml of pericardial fluid per kg of body weight, resulting in an average pericardial fluid thickness of only 0.34 +/- 0.27 mm. We next determined the pericardial fluid distribution in eight anesthetized mongrel dogs (17-29 kg). Color video images were recorded, while green dye (0.1 ml) was injected into the pericardial space overlying the ventricular apex to allow visualization of the pericardial fluid distribution. Within 26 +/- 17 s (range 15-53 s), dye reached the base of the heart. After 15 min of equilibration, the dye distribution appeared very nonuniform with dye accumulation over the interventricular and atrioventricular grooves. Little or no dye was present over the right and left ventricular free walls. We conclude that pericardial fluid thickness over the interventricular and atrio-ventricular grooves is sufficient to allow fluid motion in these regions. In contrast, pericardial fluid thickness overlying the ventricular free walls is very thin. Thus, in these regions the pericardial fluid functions primarily as a lubricant; and regional variations in pericardial pressure may occur.

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Section: Appendix a Theoretical Considerationsmentioning

confidence: 99%

Nonuniform distribution of normal pericardial fluid

1990

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Determination of vascular compliance, interstitial compliance, and capillary filtration coefficient in rat isolated perfused lungs

Uhlig

Bethmann

1997

Journal of Pharmacological and Toxicological Methods

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Effects of pulmonary fibrosis on the distribution of edema. Computed tomographic scanning and morphology.

Zwikler

Peters²,

Michel³

1994

Am J Respir Crit Care Med

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The pulmonary interstitium acts as an important safety factor against alveolar flooding. To test the hypothesis that in advanced fibrosis, edema is redistributed away from a less compliant interstitium to flood alveoli, we induced severe left lung fibrosis in six dogs with radiation and intratracheal bleomycin. Twenty-four months later, edema was induced by infusing 20% body weight lactated Ringer's solution over 30 min, preceded and followed by computed tomography (CT) scanning. Lower lobes were frozen, and samples were taken for extravascular lung water measurements (Qwl/dQl), regional blood volume, and light microscopic grading of interstitial and alveolar edema. The total volumes of the control and fibrotic lungs were 800 +/- 63 and 45 +/- 10 ml (SE), respectively, indicative of severe fibrosis. Before edema, the fibrotic carinal and basal slices had CT densities 3.5 and 2.2 times greater than respective control slices. After edema, the densities of all control lung slices rose 2.5 times and that of fibrotic carinal and basal slices rose 1.5 times. Edema significantly accentuated the small gravity-dependent gradient in CT density of control lungs, but it had minimal effect on this gradient in fibrotic lungs. The Qwl/dQl for control and fibrotic lower lobes were 8.7 +/- 0.8 and 6.8 +/- 0.7 g H2O/g dry lung, respectively, but the amounts of water per lung volume were similar, and there was no gravity-dependent gradient in Qwl/dQl or in regional blood contents. By light microscopy, we found significantly less interstitial and more alveolar edema in the fibrotic lobes. We conclude that in severe pulmonary fibrosis, similar amounts of water accumulate per lung volume as in controls, and that there is predominant alveolar flooding over interstitial edema. We also conclude that the gravity-dependent gradients in CT densities postedema in the control lungs are not accounted for by edema fluid or congestion, but probably by atelectasis.

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Pulmonary interstitial resistance

Cited by 3 publications

References 49 publications

Nonuniform distribution of normal pericardial fluid

Nonuniform distribution of normal pericardial fluid

Determination of vascular compliance, interstitial compliance, and capillary filtration coefficient in rat isolated perfused lungs

Effects of pulmonary fibrosis on the distribution of edema. Computed tomographic scanning and morphology.

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