Resolution of experimental pneumothorax in rabbits by graded oxygen therapy.

BACKGROUND

Small pneumothoraces have been treated by observation and tube thoracostomy in asymptomatic patients. Using a rabbit model, we demonstrated previously that inspired oxygen at 60% FiO2 hastened the time to resolution of complete pneumothoraces compared with room air. The present study was designed to evaluate the use of lower levels of inspired oxygen and to establish a dose-response curve for the treatment of experimental pneumothoraces.

METHODS

Forty New Zealand White rabbits were divided randomly into four groups: room air (21%) and 30, 40, and 50% FiO2. Experimental pneumothoraces were created in the rabbits, and the animals were placed in cages with the designated level of inspired oxygen. Serial chest radiographs were performed until the pneumothoraces resolved.

RESULTS

Pneumothoraces treated with room air resolved in 61.65 +/- 12.30 hours. Those treated with 30% FiO2 resolved in 42.90 +/- 5.97 hours, with 40% FiO2 in 35.80 +/- 4.26 hours, and with 50% FiO2 in 33.80 +/- 4.66 hours.

CONCLUSION

These results show a statistically significant (p < 0.01) dose-dependent improvement in the resolution of pneumothoraces with increasing levels of inspired oxygen. Supplemental oxygen therapy may be used to facilitate the resolution of small, uncomplicated pneumothoraces.