Supplemental oxygen improves resolution of injury-induced pneumothorax

Traditionally, supplemental oxygen is administered to patients with asymptomatic pneumothorax to accelerate spontaneous resolution. However, this practice is based on models that did not include injury to the visceral pleura and ongoing pleural air leak. This study evaluated the effects of increased inspired oxygen concentration on pneumothorax resolution in a visceral pleural injury model.

A total of 27 New Zealand white rabbits were divided randomly into 3 groups: room air (RA), 40% FIO2 (40%), and 60% FIO2 (60%). A complete unilateral pneumothorax was created in each animal by a thoracoscopically guided visceral pleural puncture. The animals were then housed in designated oxygen chambers, and observers were blinded to the inspired oxygen concentration. Cross table anteroposterior chest x-rays were obtained preoperatively, postoperatively, and twice a day until the pneumothorax resolved. Time to resolution between the 3 groups was analyzed with 1-way analysis of variance (ANOVA).

Twenty of 27 (74%) of the animals completed the study successfully. Mean time to resolution in the RA group (n = 7; 111.2 +/- 30.8 hours) was longer than in the 40% group (n = 6; 71.8 +/- 22.3 hours) and the 60% group (n = 7; 39.4 +/- 14.2 hours). The time to resolution also was longer in the 40% group than in the 60% group. Seven rabbits died before completion of the study of tension pneumothorax (3 of 7) or anesthetic complications (4 of 7).

Supplemental oxygen improves resolution of injury-induced pneumothorax. The tradition of administering supplemental oxygen to patients with asymptomatic pneumothorax should be continued even if there is ongoing pleural air leak.