Assessment of coagulation cascade during air microembolization of the lung

1983 ◽  
Vol 55 (6) ◽  
pp. 1743-1747 ◽  
Author(s):  
H. O'Brodovich ◽  
M. Andrew ◽  
R. Silver ◽  
G. Coates

Experiments were performed to determine whether activation of the coagulation cascade was required for pulmonary vascular permeability to increase during microembolization of the lung. For 30-45 min air microemboli were intravenously infused (0.05-0.10 ml X kg-1 X min-1) into awake sheep with chronic lung-lymph fistulas and anesthetized mongrel dogs. During embolization the pulmonary arterial pressure increased, and O2 partial pressure (PaO2) fell by more than 20 Torr (P less than 0.01). Subsequently lymph flow nearly tripled without a change in the lymph-to-plasma protein concentration ratio. Partial thromboplastin and prothrombin times, biological activity of antithrombin III, and circulating concentration of 125I-labeled dog or sheep fibrinogen did not change during or following air infusion. In two additional sheep an intravenous infusion of thrombin at 0.6 U X kg-1 X min-1 for 15 min resulted in a 20% decrease in 125I-labeled sheep fibrinogen concentration without a change in pulmonary arterial pressure or PaO2. We conclude that air microembolization can increase permeability to water and protein without a detectable activation of the coagulation cascade in the sheep or dog.

1984 ◽  
Vol 56 (4) ◽  
pp. 999-1007 ◽  
Author(s):  
J. H. Newman ◽  
J. E. Loyd ◽  
M. L. Ogletree ◽  
B. O. Meyrick ◽  
K. L. Brigham

In vitro, phorbol myristate acetate (PMA) causes sheep granulocytes to release superoxide. Infused into sheep, PMA causes leukopenia, hypoxemia, pulmonary hypertension, and increased flow of protein-rich lung lymph. Lung lymph thromboxane B2 and 6-ketoprostaglandin F1 alpha levels rise markedly after PMA infusion. To see whether cyclooxygenase products of arachidonic acid mediate the lung vascular responses to PMA, we infused 5 micrograms/kg PMA twice in each of six sheep, once in the presence of sodium meclofenamate and once alone. We varied the order of paired experiments and allowed 4–7 days between experiments. Meclofenamate (5 mg/kg loading dose + 3 mg X kg-1 X h-1 infusion) given alone had no effect on base-line variables. Meclofenamate inhibited or delayed the initial pulmonary hypertension and hypoxemia after PMA but exaggerated the later increase in pulmonary arterial pressure; it prevented any increase in thromboxane B2 and 6-ketoprostaglandin F1 alpha after PMA. Meclofenamate did not affect the degree of leukopenia or the severity of the later hypoxemia nor did it prevent accumulation of granulocytes in the lung. Lung lymph flow was higher with meclofenamate + PMA than with PMA alone, but lymph-to-plasma protein concentration ratio was lower, suggesting that the main effect of meclofenamate on lymph production after PMA was related to the degree of pulmonary hypertension. We conclude that the early increase in pulmonary arterial pressure caused by PMA is mediated by a cyclooxygenase product of arachidonic acid, possibly thromboxane A2, but the later pulmonary hypertension and the increase in pulmonary vascular permeability are not the result of cyclooxygenase products.


1994 ◽  
Vol 77 (3) ◽  
pp. 1333-1340 ◽  
Author(s):  
K. Kubo ◽  
T. Kobayashi ◽  
T. Hayano ◽  
T. Koizumi ◽  
T. Honda ◽  
...  

The purpose of the present study was to assess the role of polymorphonuclear leukocyte (neutrophil) elastase in endotoxin-induced acute lung injury in sheep with lung lymph fistula. We studied the effects of ONO-5046, a specific inhibitor of neutrophil elastase, on the lung dysfunction induced by the intravenous infusion of 1 microgram/kg of Escherichia coli endotoxin. Endotoxin alone produced a biphasic response as previously reported. Early (0.5–1 h) after endotoxin, pulmonary arterial pressure increased from 19.5 +/- 0.9 cmH2O at baseline to a peak of 46.8 +/- 2.4 cmH2O (P > 0.05). Pulmonary vascular resistance increased from 3.03 +/- 0.17 cmH2O.l–1.min at baseline to a peak of 9.77 +/- 0.70 cmH2O.l–1.min (P < 0.05). Circulating neutrophils decreased from 7,355 +/- 434/mm3 at baseline to a nadir of 1,762 +/- 32/mm3 (P < 0.05). Thromboxane B2 and 6-ketoprostaglandin F1 alpha concentrations in plasma and lung lymph were significantly increased. Late (3–5 h) after endotoxin, pulmonary arterial pressure and pulmonary vascular resistance returned to baseline levels, but lung lymph flow remained increased from 4.2 +/- 0.3 ml/0.5 h at baseline to 7.3 +/- 0.7 ml/0.5 h (P < 0.05), with a slight increase in lung lymph-to-plasma protein concentration ratio, suggesting increased pulmonary vascular permeability. The histopathological features of the lungs during the early period in sheep treated with endotoxin alone revealed a large increase in neutrophils per 100 alveoli and changes of pulmonary edema such as thickening of the interstitium of the lung and alveolar flooding.(ABSTRACT TRUNCATED AT 250 WORDS)


1995 ◽  
Vol 268 (2) ◽  
pp. R366-R374 ◽  
Author(s):  
F. Bertolino ◽  
J. P. Valentin ◽  
M. Maffre ◽  
A. M. Bessac ◽  
G. W. John

We investigated whether the stable thromboxane A2 (TxA2) analogue U-46619 had any direct effect on extracellular fluid partition. In anesthetized open-chest rats, U-46619 (1.25 and 20 micrograms/kg iv) dose dependently increased mean pulmonary arterial pressure and hematocrit, whereas mean systemic arterial pressure was raised only at the low dose of agonist. The increase in hematocrit (13.2 +/- 2.9% at 20 micrograms/kg; P < 0.05) still occurred in bilaterally nephrectomized rats and in binephrectomized plus splenectomized rats (11.6 +/- 2.7 and 12.2 +/- 4.6%, respectively; both P = NS vs. U-46619 in control rats), corresponding to a calculated decrease in plasma volume of 22.1 +/- 4.5, 19.6 +/- 4.0, and 19.2 +/- 5.8%, respectively. Plasma protein concentration increased less than hematocrit, and the coefficient of reflection was significantly lower in these groups, suggesting protein extravasation. Additional experiments showed that U-46619 (1.25 and 10 micrograms/kg iv) dose dependently increased the vascular leak of albumin mainly in lung, kidneys, and spleen but not in brain, liver, mesentery, and cardiac and skeletal muscles. Pretreatment with the TxA2 receptor antagonist SQ-29,548 (2.5 mg/kg iv bolus plus 2.5 mg.kg-1.h-1 as maintenance) abolished all effects of U-46619, including the increase in mean pulmonary arterial pressure, hematocrit, plasma protein concentration, and albumin extravasation and the decrease in mean systemic arterial pressure, plasma volume, and coefficient of reflection.(ABSTRACT TRUNCATED AT 250 WORDS)


1999 ◽  
Vol 87 (4) ◽  
pp. 1354-1359 ◽  
Author(s):  
Yasuyuki Sone ◽  
Vladimir B. Serikov ◽  
Norman C. Staub

We recently showed that we can selectively and safely deplete most (average 85%) of the pulmonary intravascular macrophages in sheep by intravenously infusing liposomes containing dichloromethylene bisphosphonate. After a 1-h stable baseline, we made a 6-h comparison after a 30-min intravenous endotoxin infusion (1 μg/kg) between six anesthetized control lambs and six anesthetized lambs in which the intravascular macrophages had been depleted 24 h previously. Three of the control lambs had been macrophage depleted and allowed to recover their intravascular macrophage population for ≥2 wk. After depletion, both the early and late pulmonary arterial pressure rises were dramatically attenuated. Our main interest, however, was in the acute lung microvascular injury response. The early and late rises in lung lymph flow and the increase in lung lymph protein clearance (lymph flow × lymph-to-plasma protein concentration ratio) were >90% attenuated. We conclude the pulmonary intravascular macrophages are responsible for most of the endotoxin-induced pulmonary hypertension and increased lung microvascular leakiness in sheep, although the unavoidable injury of other intravascular macrophages by the depletion regime may also contribute something.


1990 ◽  
Vol 68 (4) ◽  
pp. 1415-1420 ◽  
Author(s):  
D. A. Quinn ◽  
D. Robinson ◽  
C. A. Hales

Propylene glycol (30%) is the carrier base for pentobarbital sodium in preparations often used in research laboratories. It has caused pulmonary hypertension in calves, and we found it caused pulmonary hypertension in sheep as well. To investigate the mechanism of pulmonary hypertension with propylene glycol, we injected an average loading dose of 30% propylene glycol (0.5 ml/kg) into adult sheep, which was followed by a rise in thromboxane levels (P less than 0.05) in systemic arterial plasma and lung lymph and by a dramatic increase in pulmonary arterial pressure (17 +/- 1 to 35 +/- 4 mmHg, P less than 0.05) and a fall in cardiac output (2.7 +/- 0.5 to 1 +/- 0.2 l/min). Indomethacin pretreatment blocked the rise in thromboxane in lung lymph and arterial plasma and substantially, although not entirely, blocked the rise in pulmonary arterial pressure. Pulmonary intravascular macrophages (PIMS), which are present in sheep and calves, can release thromboxane in response to a stimulus. To test whether PIMS might be the source of the thromboxane and pulmonary hypertension, we injected propylene glycol into guinea pigs and dogs, which are reported to have no PIMS, as well as into newborn lambs, which are not believed to develop many PIMS until the 2nd wk of life. In dogs and guinea pigs there was no response to propylene glycol. In lambs there was a rise in pulmonary vascular resistance but significantly less than in adult sheep; indomethacin blocked this response.(ABSTRACT TRUNCATED AT 250 WORDS)


1985 ◽  
Vol 58 (3) ◽  
pp. 812-818 ◽  
Author(s):  
T. N. Hansen ◽  
A. L. Le Blanc ◽  
A. L. Gest

To assess the effects of alveolar hypoxia and angiotensin II infusion on distribution of blood flow to the lung we performed perfusion lung scans on anesthetized mechanically ventilated lambs. Scans were obtained by injecting 1–2 mCi of technetium-labeled albumin macroaggregates as the lambs were ventilated with air, with 10–14% O2 in N2, or with air while receiving angiotensin II intravenously. We found that both alveolar hypoxia and infusion of angiotensin II increased pulmonary vascular resistance and redistributed blood flow from the mid and lower lung regions towards the upper posterior region of the lung. We assessed the effects of angiotensin II infusion on filtration pressure in six lambs by measuring the rate of lung lymph flow and the protein concentration of samples of lung lymph. We found that angiotensin II infusion increased pulmonary arterial pressure 50%, lung lymph flow 90%, and decreased the concentration of protein in lymph relative to plasma. These results are identical to those seen when filtration pressure increases during alveolar hypoxia. We conclude that alveolar hypoxia and angiotensin II infusion both increase fluid filtration in the lung by increasing filtration pressure. The increase in filtration pressure may be the result of a redistribution of blood flow in the lung with relative overperfusion of vessels in some areas and transmission of the elevated pulmonary arterial pressure to fluid-exchanging sites in those vessels.


1982 ◽  
Vol 53 (3) ◽  
pp. 543-548 ◽  
Author(s):  
P. S. Barie ◽  
A. B. Malik

We examined the effects of left pulmonary arterial occlusion and reperfusion on pulmonary transvascular fluid and protein exchange in the sheep lung lymph fistula preparation. Pulmonary lymph flow (Qlym) increased from the base-line value of 5.0 +/- 0.8 to 10.0 +/- 2.1 ml/h after occlusion (P less than 0.05); the steady-state value of 11.9 +/- 2.2 ml/h during reperfusion was not significantly different from the value during occlusion. The lymph-to-plasma protein concentration ratio (L/P) did not change significantly during either occlusion or reperfusion. Transvascular protein clearance (Qlym X L/P) increased from 3.7 +/- 0.6 to 8.4 +/- 2.1 ml/h during occlusion (P less than 0.05) and remained elevated at 8.6 +/- 1.7 ml/h during reperfusion. The sustained increases in Qlym and protein clearance could not be explained by the 3-Torr increase in mean pulmonary arterial pressure during the occlusion period or by an increase in the interstitial protein concentration caused by a period of decreased filtration during occlusion. The increases in protein clearance that occurred with increased Qlym during occlusion and reperfusion were greater than the increases in protein clearance with comparably increased Qlym during left atrial hypertension. The results suggest that occlusion of a pulmonary artery increases vascular permeability to plasma proteins in the lung.


1989 ◽  
Vol 66 (3) ◽  
pp. 1287-1296 ◽  
Author(s):  
D. B. Pearse ◽  
R. G. Brower ◽  
N. F. Adkinson ◽  
J. T. Sylvester

Perfusion of isolated sheep lungs with blood causes spontaneous edema and hypertension preceded by decreases in perfusate concentrations of leukocytes (WBC) and platelets (PLT). To determine whether these decreases were caused by pulmonary sequestration, we continuously measured blood flow and collected pulmonary arterial and left atrial blood for cell concentration measurements in six lungs early in perfusion. Significant sequestration occurred in the lung, but not in the extracorporeal circuit. To determine the contribution of these cells to spontaneous injury in this model, lungs perfused in situ with a constant flow (100 ml.kg-1.min-1) of homologous leukopenic (WBC = 540 mm-3, n = 8) or thrombocytopenic blood (PLT = 10,000 mm-3, n = 6) were compared with control lungs perfused with untreated homologous blood (WBC = 5,320, PLT = 422,000, n = 8). Perfusion of control lungs caused a rapid fall in WBC and PLT followed by transient increases in pulmonary arterial pressure, lung lymph flow, and perfusate concentrations of 6-ketoprostaglandin F1 alpha and thromboxane B2. The negative value of reservoir weight (delta W) was measured as an index of fluid entry into the lung extravascular space during perfusion. delta W increased rapidly for 60 min and then more gradually to 242 g at 180 min. This was accompanied by a rise in the lymph-to-plasma oncotic pressure ratio (pi L/pi P). Relative to control, leukopenic perfusion decreased the ratio of wet weight to dry weight, the intra- plus extravascular blood weight, and the incidence of bloody lymph. Thrombocytopenic perfusion increased lung lymph flow and the rate of delta W, decreased pi L/pi P and perfusate thromboxane B2, and delayed the peak pulmonary arterial pressure. These results suggest that perfusate leukocytes sequestered in the lung and contributed to hemorrhage but were not necessary for hypertension and edema. Platelets were an important source of thromboxane but protected against edema by an unknown mechanism.


1984 ◽  
Vol 56 (4) ◽  
pp. 979-985 ◽  
Author(s):  
R. Winn ◽  
J. Stothert ◽  
B. Nadir ◽  
J. Hildebrandt

Lung injuries were produced by instilling 2.5 ml/kg of 0.1 N HCl into the trachea of lightly anesthetized goats with previously implanted lung lymph fistulas. Lymph flow (QL), lymph-to-plasma protein concentration ratio (L/P), pulmonary arterial and wedge pressures (Ppa, Pw), percent shunt (Qs/QT), and postmortem extravascular lung water (EVLW) were then measured for up to 48 h. QL began to increase within 15 min of injury from a baseline value of 7.2 ml/h to reach a peak of 231% of base line by 1.5 h, then decreased to 160% at 24 h and returned to base line by 48 h. Average L/P increased from 0.66 to a peak of 0.73 at 2 h. Ppa increased from 17.0 cmH2O to a first peak of 25.3 cmH2O at 15 min, then decreased to base line by 75 min. There was a second rise that peaked at 3 h before returning to base line at 24–48 h; Pw was unchanged throughout. Qs/QT increased from 8.5 to a peak of 34% at 1 h, then decreased to 15% at 4 h, and stabilized at 17–20% at 48 h. EVLW was 237% of base line at 4 h and declined somewhat but remained elevated at 194% of base line at 24 and 48 h. Qs/QT was less than expected based on the reduction in lung volume after aspiration. We conclude that microvascular permeability was increased after acid and that a protective vasoconstriction, probably due to local hypoxia, directed blood away from nonventilated alveoli.


1987 ◽  
Vol 63 (6) ◽  
pp. 2201-2207 ◽  
Author(s):  
H. Kobayashi ◽  
T. Kobayashi ◽  
M. Fukushima

To assess the role of intracellular adenosine 3′,5′-cyclic monophosphate (cAMP), we tested the effects of dibutyryl cAMP (DBcAMP), an analogue of cAMP, on lung injury induced by pulmonary air embolism in awake sheep with chronic lung lymph fistula. We infused air (1.23 ml/min) in the pulmonary artery for 2 h in untreated control sheep. In DBcAMP-pretreated sheep DBcAMP was infused (1 mg/kg bolus and 0.02 mg.kg-1.min-1 constantly for 5 h); after 1 h from beginning of DBcAMP administration the air infusion was started. After the air infusion, pulmonary arterial pressure (Ppa) and lung lymph flow rate (Qlym) significantly increased in both groups. DBcAMP-pretreated sheep showed significantly lower responses in Qlym (2.7 X base line) compared with untreated control sheep (4.6 X base line); however, Ppa, left atrial pressure, and lung lymph-to-plasma protein concentration ratio were not significantly different between the two groups. Although plasma and lung lymph thromboxane B2 and 6-ketoprostaglandin F1 alpha concentrations increased significantly during the air infusion, DBcAMP-pretreated sheep showed significantly lower responses. Thus DBcAMP infusion attenuated pulmonary microvascular permeability induced by air embolism. We conclude that pulmonary vascular permeability is in part controlled by the intracellular cAMP level.


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