[The functionally amputated lung. Studies on the unilateral hyperlucent lung syndrome].

On the basis of comprehensive clinicopathological evidence 6 patients presenting with unilateral left-sided hyperlucent lungs are evaluated for pathogenesis, function and postoperative (n = 5) course. The common denominator in all proves to be moderate to severe hypoperfusion and overinflation of the respective lungs. Pulmonary function is characterized by a combined restrictive-obstructive pattern. In 4 patients overinflation is due to a central check-valve mechanism (tumor: n = 3; central airways collapse: n = 1), whereas in 2 increased translucency results from some sort of peripheral obstruction (Swyer-James syndrome: n = 1; congenital cystic bronchiectasis: n = 1). We consider the origin of hypoperfusion to be alveolar distension and hypoxic precapillary vasoconstriction, both participating in diminished blood flow to the check-valve obstructed lung. In Swyer-James syndrome reduced vascularity is an additional feature. Preoperative and long-term postoperative lung function data of 5 pneumonectomized patients are compared. On the whole, FEV1 and IVC remain unchanged, whereas the obstructive profile (RV, RV/TLC, sRAW) improves. From these data it is concluded that the affected hyperlucent lung is 'amputated' even before operation - irrespective of the nature of tissue damage. On the other hand postoperative relief of airways obstruction is supposed to be due to both antiobstructive medication and the removal of a diseased lung.