Pulmonary Vein Pressure Research Articles

Effect of gram-negative endotoxin on pulmonary circulation.

Effects of endotoxin on the pulmonary hemodynamics of dogs and cats have been studied in intact animals, open chest animals with and without control of cardiac output by an extracorporeal venous reservoir—pump system, and in isolated perfused continuously weighed lungs. Pulmonary artery pressure increased without a rise in left atrial pressure in all preparations following the injection of endotoxin. Pulmonary artery wedge and small pulmonary vein pressures uniformly increased. Total pulmonary vascular, pulmonary arterial and pulmonary venous resistances were calculated in five perfused lungs. The absolute increase in pulmonary venous resistance was greater than in the arterial resistance in four of the five studies and was relatively greater in every instance. There was a consistent increase in lung weight associated with these hemodynamic changes. Analysis of the determinants of lung weight changes has provided evidence to support the conclusion that the pulmonary vascular response to endotoxin administration is characterized predominantly by constriction of pulmonary venules and/or small veins.

Influence of low oxygen tension on pulmonary circulation after temporary arrest of ventilation in curarized dogs.

The purpose of this study was to investigate the influence of moderate hypoxia on the pulmonary circulation after eliminating the ventilatory response to hypoxia and its secondary effects on the circulation. After Pentothal anesthesia, 10 dogs were fitted with catheters in the pulmonary artery and vein, right atrium and descending aorta. Respiratory arrest was induced by curare-like compounds and mechanical breathing installed. Photokymographic records of pressures and cardiac output determinations were made during artificial respiration and at the end of 90-second periods of 'apneic oxygenation' and 'apneic hypoxia.' Apneic oxygenation is a period of respiratory arrest following denitrogenation of the animal and during which the trachea is connected to a reservoir containing 100% O2. Apneic hypoxia is a period of respiratory arrest following ventilation with room air. Both periods were marked by an increase in alveolar pCO2 not exceeding 20 mm Hg. After 90 seconds of apneic oxygenation mean pulmonary and vein pressure, and pressure gradient between pulmonary artery and vein were significantly lowered. Mean femoral artery was significantly increased. Cardiac output and calculated pulmonary and peripheral resistance were not changed. During apneic hypoxia (with arterial oxygen saturation averaging 46%), mean pulmonary artery, pulmonary vein and femoral artery pressure and pressure gradient between pulmonary artery and vein were significantly increased. Calculated pulmonary and peripheral resistance rose significantly from 2.6 to 3.7 and 40 to 48 mm Hg/l/min., respectively. These increases occurred in the presence of a significant fall in heart rate and in right atrial pressure, and while cardiac output did not change significantly. Submitted on March 8, 1956

Transposed pulmonary veins: A correlation of clinical and cardiac catheterization data

Ten patients with transposed pulmonary veins are described. These include four patients with partial and two with complete pulmonary vein transposition, in whom cardiac catheterization and clinical findings are correlated. The other patients presented (1) pulmonary valvular stenosis accompanied by partial pulmonary vein transposition, (2) a left superior vena cava entering a sinus venosus in common with the hepatic veins, accompanied by anomalous drainage of the right pulmonary veins into the right atrium, and (3) probable tricuspid atresia with partial pulmonary vein transposition (two cases). The diagnosis of anomalous pulmonary vein drainage in these cases was made at cardiac catheterization by roentgen visualization of the catheter in the anomalous vein, by a characteristic pulmonary vein pressure curve and finally by 90 to 95 per cent oxygen saturation in the blood sample from the anomalous vein. Surgical exploration and attempts to correct this anomaly should be reserved for those patients with complete transposition in whom limitation of physical activity is progressive.

Cardiac function in experimental mitral stenosis.

The results of 85 combined right and left heart catheterizations in normal dogs and dogs with experimental mitral stenosis are presented. Animals lived as long as 10 months with elevated pulmonary vein pressures. Pulmonary vein pressures in excess of 15 mm. Hg were associated with mitral orifice areas which were smaller than those found in normal animals. Elevation of pulmonary vein pressure was associated with a decrease in the pulmonary vascular pressure gradient, with no change in cardiac index as measured and with a decrease in calculated pulmonary vascular resistance.

An evaluation of wedge pressures in dogs under conditions of normal and elevated pulmonary vascular pressures.

Fifty-six combined right and left heart catheterizations in normal dogs and dogs with experimental mitral stenosis failed to show a significant positive correlation between pulmonary artery wedge pressure and pulmonary vein pressure when the latter was below approximately 17 mm. Hg. Evidence is presented which suggests that the wedged catheter outlets are totally occluded in many instances in the dog. Pulmonary vein wedge pressure reflected a pressure nearer the pulmonary artery pressure than the expected capillary pressure. One instance of mitral regurgitation revealed large pulmonary vein and pulmonary artery wedge pulse pressures.