Supplemental oxygen improves resolution of injury-induced pneumothorax

Background/Purpose: Traditionally, supplemental oxygen is administered to p atients 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 resoluti on in a visceral pleural injury model. Methods: A total of 27 New Zealand white rabbits were divided randomly into 3 groups: room air (RA), 40% FiO(2) (40%), and 60% FiO(2) (60%) A complete unilateral pneumothorax was created in each animal by a thoracoscopically guided visceral pleural puncture. The animals were then housed in designate d oxygen chambers, and observers were blinded to the inspired oxygen concen tration. Cross table anteroposterior chest x-rays were obtained preoperativ ely, postoperatively, and twice a day until the pneumothorax resolved. Time to resolution between the 3 groups was analyzed with 1-way analysis of var iance (ANOVA). Results: 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% grou p (n = 7; 39.4 +/- 14.2 hours). The time to resolution also was longer in t he 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). Conclusions: Supplemental oxygen improves resolution of injury-induced pneu mothorax. The tradition of administering supplemental oxygen to patients wi th asymptomatic pneumothorax should be continued even if there is ongoing p leural air leak.