Perioperative Supplemental Oxygen and Plasma Catecholamine Concentrations after Major Abdominal Surgery-Secondary Analysis of a Randomized Clinical Trial.

Perioperative stress is associated with increased sympathetic activity that leads to increases in heart rate and blood pressure, which are associated with the development of perioperative myocardial ischemia. In healthy volunteers, it was shown that the administration of supplemental oxygen attenuated sympathetic nerve activity and subsequently led to lower plasma catecholamine concentrations. We therefore tested the hypothesis that perioperative supplemental oxygen attenuates sympathetic nerve in patients at risk for cardiovascular complications undergoing major abdominal surgery. We randomly assigned 81 patients to receive either 80% or 30% inspired oxygen concentration throughout surgery and the first two postoperative hours. We assessed noradrenaline, adrenaline, and dopamine plasma concentrations before the induction of anesthesia, two hours after surgery and on the third postoperative day. There was no significant difference in postoperative noradrenaline (effect estimated: -41.5 ng·L, 95%CI -134.3, 51.2; = 0.38), adrenaline (effect estimated: 11.2 ng·L, 95%CI -7.6, 30.1; = 0.24), and dopamine (effect estimated: -1.61 ng·L, 95%CI -7.2, 3.9; = 0.57) concentrations between both groups. Based on our results, it seems unlikely that supplemental oxygen influences endogenous catecholamine release in the perioperative setting.