Introduction Recently I was notified that a rumor among freedivers regarded the use of oxygen as a rescue gas being dangerous. It was further claimed that the diving medicine world would have officially doubt the use of oxygen as a safe gas to use in diving emergencies. In this article, I have tried to research this claim and have searched for the current advice concerning the use of oxygen as rescue gas. Finding the root of the rumor Contact with Divers Alert Network soon learned that there was no doubt on the use of oxygen drowning victims. Also extensive search on medical libraries as PubMed did not herald any evidence that there was any doubt on the use of oxygen as a rescue gas. Based on questions of oxygen providers and divers, it seemed that a possible cause of such a rumor could have been caused by the phenomenon of reactive oxygen species that can develop after reperfusion after ischemia. In the article Loss of consciousness: reactive oxygen species after hypoxia will this phenomenon discussed. Current standards on oxygen and drowning. In leading books as The Handbook on Drowning, 100% Oxygen is noted one of the first steps in initial treatment. While the authors do acknowledge that the use of 100% oxygen has been controversial. Experimental models would suggest a more effective effect of room air. Research on asphyxia with new born children showed now difference in clinical long-term outcome between air room and 100% oxygen. However, it should be noted that drowning victims can be troubled by aspiration of water or gastric contents. Not noted by the authors, but known for freediving, hemoptysis or blood in the lungs also will hamper the distribution of oxygen. Room air will probably lead to hypoxia in these cases and should therefore 100% oxygen should be used in the initial resuscitation. Also books on diving medicine do still recommend the use of 100% oxygen towards drowning victims (including the formerly used near-drowning victims). While acute oxygen toxcitity is possible with 100% oxygen, it will only happen after 12 to 16 hours of exposure in a normal breathing person. Conclusion It is no question if 100% oxygen should be used in emergency situations with freediving. Sources Handbook on Drowning, Prevention, Rescue, Treatment, Bierens, Joost J.L.M. (Ed.),
2006, XLIV, 714 p. 100 illus., Hardcover, ISBN: 3-540-43973-0 Bove and Davis'Diving Medicine by Alfred A. Bove, Jefferson Davis, W.B. Saunders Company; 4th edition (October 10, 2003) ISBN: 0721694241
Loss of conciousness:
Oxygen as rescue gas