Aim: to investigate the effect of a high inspiratory oxygen fraction (FiO2) given during and
after laparotomy procedures on occurrence of a subsequent, new or recurrent, cancer diagnosis
at a long-term follow-up.
Background: A high inspiratory oxygen fraction (FiO2 = 0.80) has been linked to prevention of
surgical site infection, but the Danish randomized clinical multicenter trial, the PROXI
trial, found no difference in frequency of surgical site infection. In fact, long-term
mortality was significantly increased with a hazards ratio of 1.30 in patients receiving 80%
oxygen, and this appeared to be statistically significant in patients undergoing cancer
surgery, but not in non-cancer patients.
At this point, no convincing mechanism explains the observed increased mortality after
hyperoxia, as the long-term pathophysiological effects of oxygen are not fully understood.
Primary hypothesis of this follow-up study of the PROXI trial: Use of 80% oxygen increase the
frequency of patients with a subsequent, new or recurrent, cancer.