Resolution of experimental pneumothorax in rabbits by oxygen therapy

The treatment of asymptomatic patients with small pneumothoraces (ie, less than 20% by volume) has included observation, tube thoracostomy, and operation. When observation is used, the anticipated expansion of the lung has been estimated to be 1.25% of the lung volume daily. This study was designed to evaluate the use of inhaled oxygen as a method to accelerate the resolution of a pneumothorax in a rabbit model. Experimental pneumothoraces were created in 23 white New Zealand rabbits. Group 1 (9 rabbits) were placed in a cage with room air and group 2 (11 rabbits) were placed in a cage with high oxygen concentration. Three rabbits died before completion of the study. Serial chest roentgenograms were performed until the pneumothoraces resolved. The majority of rabbits treated with oxygen had resolution of their pneumothoraces by 36 hours, whereas the majority of rabbits treated with room air did not show complete resolution before 48 hours. Biopsies showed no evidence of damage secondary to oxygen treatment. Oxygen treatment was found to be significantly better in the early resolution of pneumothoraces when compared with room air. This establishes an alternative treatment for some pneumothoraces that are small and asymptomatic.