Lung lymph and free interstitial fluid protein composition in sheep with edema

Vreim, C. E.; Snashall, P. D.; Rh, Demling; Nc, Staub

doi:10.1152/ajplegacy.1976.230.6.1650

Cited by 77 publications

(22 citation statements)

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“…If we assume that the concentration of protein in lymph approximates that in the pulmonary interstitium, as others have shown (30,44), then measurement of lung lymph flow and the concentration of protein in lymph provides a sensitive index of net transvascular movement of fluid and protein in the lung (4,8,39,40). Our results, therefore, suggest that alveolar hypoxia increases net transvascular filtration of fluid into the lungs of lambs.…”

Section: Discussionsupporting

confidence: 61%

Lung Fluid Balance in Hypoxic Lambs

et al. 1984

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SummaryIn spontaneously breathing newborn lambs, alveolar hypoxia increases lung microvascular pressure, which causes lung lymph flow to increase and the concentration of protein in lymph to decrease. To see if this response derives from hypoxia itself rather than from the change in breathing pattern that occurs during hypoxia, we measured lung vascular pressures, pleural pressure, cardiac output, and lung lymph flow in 12 anesthetized lambs that were ventilated at a fixed rate and tidal volume, first with air, then with 10-14% O2 in nitrogen. Alveolar hypoxia did not affect pleural pressure, but pulmonary arterial pressure increased from 19 to 32 torr, lung lymph flow increased from 2.20 to 3.83 ml/h and lymph protein concentration decreased from 3.4 to 2.8 g/dl. To be certain that the increased lymph flow associated with hypoxia is not simply the result of an acute release of fluid from the lungs and to assess the effects of carbon dioxide on lymph flow during hypoxia, we next studied six unanesthetized lambs kept hypoxic for a total of 12 h. After a 2-4-h period in air the lambs breathed 9-11% 0 2 in nitrogen for 2-4 h, then 8-11% O2 and 3-5% C02 in nitrogen for 8-10 h. In these lambs we injected intravenously radioactive albumin and measured its uptake in lymph to see if sustained hypoxia alters microvascular permeability to protein in the lungs. In these experiments pulmonary arterial pressure increased from 17 to 37 torr, lung lymph flow increased from 1.74 to 3.28 ml/h, and lymph protein concentration decreased from 3.8 to 3.1 g/dl during hypoxia. Addition of C02 to the inspired gas did not affect steady state lung lymph flow. Lymph flow remained elevated throughout the 12 h of alveolar hypoxia, and postmortem lung water determinations were not different from those of controls (4.65 f 0.28 versus 4.72 f 0.14 g/g dry bloodless lung). The time required for radioactive albumin to equilibrate in lymph at one-half the specific activity of plasma was no different before and during hypoxia (130 + 7 versus 125 f 11 min). We conclude that in the newborn lamb, alveolar hypoxia increases transvascular fluid filtration by increasing microvascular hydraulic pressure without altering microvascular permeability to protein. This response is independent of changes in pleural pressure or inspired carbon dioxide. Bressack and Bland (5,6) showed that alveolar hypoxia increases lung lymph flow and decreases lymph protein concentration in newborn lambs. They concluded that alveolar hypoxia increases transvascular fluid filtration in the lung by increasing filtration pressure without altering microvascular permeability to protein.At least two issues were unanswered by the previous studies. First, because Bressack and Bland used unanesthetized lambs that breathed spontaneously, hypoxia caused hyperventilation and a resultant decrease in arterial Pco2 and pleural pressure. Arterial Pco2 may influence pulmonary vascular tone (20,25) and pleural pressure may influence lung interstitial fluid pressure (1 4,2 I, 27,38,45); it is poss...

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Section: Discussionsupporting

confidence: 61%

Lung Fluid Balance in Hypoxic Lambs

et al. 1984

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“…The reaction is dose-related and reproducible for up to three studies in a given sheep (1). There is a sizeable body of data supporting the assumption that lung lymph flow and protein concentrations under steady-state conditions reflect the flow and protein concentration oftransmicrovascular filtrate in the lung (17)(18)(19). Therefore the high flow ofprotein rich lymph seen during the steadystate late phase of the endotoxin reaction is interpreted as increased lung vascular permeability to fluid and protein (1).…”

Section: Discussionmentioning

confidence: 83%

Prevention by granulocyte depletion of increased vascular permeability of sheep lung following endotoxemia.

Heflin¹,

Brigham²

1981

J. Clin. Invest.

394

116

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A B S T R A C T To see whether circulating granulocytes are necessary for the lung vascular reaction to endotoxin, we measured the endotoxin response in chronically instrumented sheep before and after granulocyte depletion with hydroxyurea. Granulocyte depletion did not affect the pulmonary hypertension caused by endotoxin (peak mean pulmonary artery pressures = 38+2 cm H20 before depletion and 42+2 after depletion, P = NS). The late phase increase in lung lymph flow after endotoxin was significantly lower in the granulocytopenic animals as reflected by lung lymph flow (mean steady state lymph flow before depletion = 30.6+2.0 SE ml/h; mean steady state lymph flow after granulocyte depletion = 15.4+1.0; P < 0.01) even though late phase pulmonary vascular pressures were similar before and after granulocyte depletion. Lung lymph protein clearance (lymph flow x lymph/plasma protein concentration) was also significantly lower after granulocyte depletion (mean steady state before depletion = 21.4 + 1.4 SE ml/h; and after depletion = 10.4+ 1.0; P < 0.01). We conclude that circulating granulocytes are necessary for the development of increased lung vascular permeability to fluid and protein following endotoxin. The pulmonary vasopressor effects of endotoxin in sheep are independent of granulocytes.

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“…Under steady state conditions, lung lymph flow reflects net filtration of liquid from the pulmonary circulation into the interstitium, and the protein concentration of lung lymph approximates that of lung interstitial liquid (33). Our results indicate that a PDA is associated with increased lymph flow rates and protein clearance in prematur_e lambs.…”

Section: Discussionmentioning

confidence: 54%

Patent Ductus Arteriosus Increases Lung Fluid Filtration in Preterm Lambs

et al. 1991

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ABSTRACT. Previous studies showed that increased pul-The DA is a fetal vascular channel that normally closes soon monary blood flow from a patent ductus arteriosus had after birth. If it remains patent, as it often does after premature little or no effect on the amount of fluid in the lungs of birth, blood flow from the aorta into the pulmonary artery mechanically ventilated preterm lambs. The purpose of increases as pulmonary vascular resistance decreases postnatally. this study was to examine the effect of a patent ductus A PDA is thus associated with increased pulmonary blood flow, arteriosus on lung vascular permeability and to see whether pulmonary blood pressure, and PLvED (1, 2). The presence of a increased pulmonary lymph flow might compensate for the PDA may cause pulmonary edema in premature infants with increased rate of fluid filtration. Using a model that allows respiratory distress (3,4). However, little information is available mechanical control of ductus patency, we studied the effects to demonstrate how the PDA adversely affects pulmonary fluid of increased pulmonary blood flow on lung vascular pres-balance. sures in six mechanically ventilated premature lambs at Several studies have examined the effects of increased pulmo-We nary blood flow on lung fluid balance in adult and mature measured lung lymph flow and protein concentrations in newborn animals (5-1 1). In some of these studies, the increase lymph and plasma to assess pulmonary vascular fluid in microvascular fluid filtration associated with increased pulfiltration and protein permeability. We studied each lamb monary blood flow was attributed to increased microvascular during sequential steady state periods, first with the ductus filtration pressure (5, 6, 1 1); in other studies, the increased open and then with it closed. When the ductus was open, filtration was thought to be the result of lung vascular recruitment pulmonary blood flow was twice what it was when the (7-10). There is some evidence that the capacity for vascular ductus was closed. Mean pulmonary artery pressure and recruitment and increased fluid filtration in the pulmonary cirleft ventricular end-diastolic pressure were greater with culation may be age dependent (10-13). Little information is the ductus open [40 +. 5 torr (5.3 f 0.7 kPa) and 8 f 3 available regarding the influence of increased perfusion on lung torr (1.1 f 0.4 kPa), respectively] than when it was closed fluid filtration in the presence of underlying pulmonary pathol-124 f 3 torr (3.2 f 0.4 kPa) and 4 f 2 torr (0.5 f 0.3 ogy (9, 14), and the relationship between blood flow and fluid kPa), respectively]. When the ductus was open, lymph flow dynamics in the immature lung is even more obscure. was 68% greater and lymph protein concentration was 17%We used an animal model of the PDA that enables us to study lower than when the ductus was closed. Lymph protein the effects of increased pulmonary blood flow on lung fluid clearance (lymph flow % lymph protein concentration/ balance in newborn sheep (1,2,15). Pr...

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Lung lymph and free interstitial fluid protein composition in sheep with edema

Cited by 77 publications

References 0 publications

Lung Fluid Balance in Hypoxic Lambs

Lung Fluid Balance in Hypoxic Lambs

Prevention by granulocyte depletion of increased vascular permeability of sheep lung following endotoxemia.

Patent Ductus Arteriosus Increases Lung Fluid Filtration in Preterm Lambs

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