The Oxygen Dilemma

Toxic Effects of Oxygen on Cultured Human Neonatal Respiratory Epithelium

“…An additional problem with interpretation of previous studies is that the tissues have usually been simultaneously exposed to prolonged positive pressure ventilation and other potential sources of injury such as endotracheal intubation and suction, altered humidity, infection, and drugs. Observed changes, therefore, have not been unequivocally oxygen-induced [3]. In one study with a design more appropriate for the determination of oxygen-induced changes, cat tracheal mucus flow was markedly impaired after a brief exposure to 100% oxy- gen [9].…”

Effects of Inspired Oxygen on the Metabolism of Pulmonary Surfactant.

“…The problem has assumed increased significance since 1940 as certain military weapon systems have required personnel to be subjected to environments containing above ambient concentrations of oxygen, and since oxygen is often required for the management of acute and chronic respiratory failure. The ultimate outcome of breathing 100% oxygen is without doubt (2). Structural damage to endothelial and Type I epithelial cells occurs, leading to a breach of the air-blood barrier.…”

“….hhnca -Il become appreciated (2). Curiously, the question still remains unresolved, and takes an added significance because of recent studies on the cytokinetics of lung cells.…”

Purification of Alveolar Epithelial Type II Cells from Rat Lung.

“…(20 , 27), hyperplasia of alveolar Type II cells ( 1,20) , accumula tion of in ters titial and alveolar fluid (6 , 16) , depos ition of hyaline membranes (6 , 41), and in terference with the forma tion or func tion of pulmonary surfactant (11). Physiological manifestations of these changes result in decreasing 02 uptake because of impaired diffusion (5,18), V/~ abnormalities ( 6 ), decreased pulmonary compliance ( 5 ), and alveolar atelectasis ( 6,35). Desp ite this rather detailed description of the morphological and physiological changes resultant from the chronic inhalation of oxygen , the biochemical bases of these lesions are ouly speculative.…”

“…results in capillary wall destruction , protein transudation into the alveolar lumen , and in ter stit ial and alv eolar edema ( 6 ) . Certain constituents of edema fluid may be capable of interacting with pulmonary surfactant and altering its physical properties (35,37).…”