Veno-arterial difference in alpha 1 -antitrypsin levels

alpha(1)-Antitrypsin levels, determined by radial immunodiffusion, were found to be higher in the venous than in the arterial blood of patients with pulmonary infections and in patients with obstructive airflow diseases. Large differences occurred in patients with both abnormalities. No difference was found in patients with other kinds of lung disease or in patients without lung disease. The veno-arterial difference probably occurs as blood passes through the lungs and probably results from alteration of the immunological properties of the alpha(1)-antitrypsin, perhaps by attachment to proteases, rather than absorption into the lung tissue. Further studies are needed to define the diseases in which this antienzyme plays an active part and to determine the mechanisms causing the difference.

Value of arterialized capillary blood gas analysis in lower respiratory tract infection in childhood

Blood gas analysis on arterialized capillary blood in 70 young infants yielded satisfactory information about oxygen therapy. Inspired oxygen concentrations above 40% are often required to raise the capillary Po₂ of hypoxic infants above 70 mmHg. Oxygen concentrations above 40% are difficult to achieve and maintain in presently available oxygen tents, though not in modern incubators, or oxygen chairs. A raised Pco₂ has frequently been found in infants with severe respiratory infections, but oxygen therapy has not resulted in CO₂ narcosis in these acute emergencies.