HELIOX THERAPY FOR PNEUMOTHORAX - NEW INDICATION FOR AN OLD REMEDY

Study objective: To evaluate a new method of treating pneumothorax: ha ving the subject breathe a helium/oxygen mixture (heliox). Methods: We conducted a prospective, randomized, controlled study of nine white r abbits weighing 2.5 to 3.5 kg. Experimental pneumothorax was induced i n all rabbits with the injection of 20 mt of air into the pleural spac e. The rabbits then breathed heliox, oxygen, or room air for 2 hours. Chest radiography was performed 5 minutes after induction of pneumotho rax, then at 1 and 2 hours. We determined pneumothorax size on the che st radiograph by measuring the interpleural distance and expressing it as a percentage of the hemithorax. Results: At 2 hours the pneumothor aces in the heliox group had diminished from 17.50%+/-.50% to .17%+/-. 29%; in the oxygen-breathing group they had diminished from 17.83%+/-2 .25% to .50%+/-.50%; and in the air-breathing group they had diminishe d from 18.50%+/-3.12% to 17.33%+/-.25%. The difference between the air -breathing and the oxygen-breathing or heliox-breathing animals was hi ghly significant; no significant difference was found between the oxyg en and heliox groups (P<.0001). Conclusion: Heliox, a safe and conveni ent therapy, is as effective as oxygen in reducing the volume of an ex perimental pneumothorax in rabbits.