Anyone who suffers a serious accident is now given high-dose oxygen at an early stage by all emergency services around the world. This procedure has been recommended in international guidelines and taught in medical training for decades. Oxygen as a medication is widespread, readily available, inexpensive - and vital. So what are the arguments against the common practice of early and high-dose oxygen administration to seriously injured patients?

This question was investigated in an international study involving researchers from the University of Bern together with colleagues from Denmark, the Netherlands and Germany. A total of five large trauma centers and 15 rescue helicopters took part in the study - in Switzerland, the Inselspital Bern and three helicopters from the Swiss Air-Rescue Rega. With a total of 1,508 participants, the study investigated whether lower oxygen administration compared to high-dose oxygen administration in the first eight hours after a physical trauma reduces the mortality rate or complications within 30 days. This is by far the world's largest study on oxygen administration in severely injured patients. The results were recently published in the journal JAMA.

Ethical aspects of the study

In the first eight hours after an accident, the participants were either given the usual high-dose oxygen or only as much as they needed to ensure sufficient oxygen in their blood. Two ethical questions had to be clarified in advance: Should seriously injured patients be deprived of standard therapy? The reviewing ethics committee accepted this, as the oxygen concentration in accident victims is always routinely monitored. In addition, until recently it was assumed that oxygen has no side effects and is rather useful in cases of doubt. However, more recent findings call this assumption into question, with the result that there is hardly any reliable evidence for the benefits of high-dose oxygen.

The question of whether patients who are incapable of judgment, such as unconscious patients, may be included in this study could also be answered in the affirmative from an ethical perspective, as the Human Research Act allows seriously injured patients or their relatives in emergency situations to subsequently consent to - or withdraw - their participation in the study. The participants could therefore be randomly assigned to one of the two oxygen treatments in the Rega helicopter or in the emergency room, in accordance with the scientific and methodological standard for an experimental study. The patients' recovery was then monitored for a month and the collected data was included in the study.  

No differences between the two therapies

Wolf Hautz, co-author of the study and head of invasive emergency interventions at Inselspital, Bern University Hospital, comments on the results of the study: “Oxygen is vital - without it, a person dies within a few minutes. Surprisingly, however, lower oxygen administration did not lead to any difference in mortality or respiratory complications compared to high-dose oxygen administration. This fundamentally calls into question the long-standing dogma that 'seriously injured people need a lot of oxygen'.”  

Too much oxygen can even be harmful: New studies indicate that high doses of oxygen can cause serious damage to newborn babies. It has also been shown that the recovery of stroke and heart attack patients is better if they receive enough oxygen, but not too much. The study suggests that moderate oxygen administration should also be considered for severely injured patients in order to avoid complications such as inflammatory reactions and lung damage.

The study gives cause for hope: “Despite the major ethical, legal, medical and logistical challenges that research in highly acute emergency situations entails, it is possible to successfully conduct such studies in close collaboration,” says Roland Albrecht, co-author of the study and Rega's chief physician.