Key result
Perioperative administration of 80% supplemental oxygen did not significantly affect postoperative plasma noradrenaline (MD -41.5 ng/L, p=0.38), adrenaline, or dopamine concentrations compared to 30% oxygen in patients at risk for cardiovascular complications undergoing major abdominal surgery.
Why the study?
Supplemental oxygen attenuated sympathetic nerve activity in healthy volunteers, but evidence was lacking in surgical patients at risk for cardiovascular complications.
Does 80% inspired oxygen concentration reduce postoperative plasma catecholamine concentrations in patients at risk for cardiovascular complications undergoing major abdominal surgery?
RCT (n=81)
Double-blind
Web-based randomization program using permutated blocks
No
Does 80% inspired oxygen concentration reduce postoperative plasma catecholamine concentrations in patients at risk for cardiovascular complications undergoing major abdominal surgery?
Mean Difference: -41.5 (95% CI -134.3–51.2)
p-value: p=0.38
Does not support hyperoxia to blunt catecholamines in high-risk surgery; challenges mechanistic rationale and reinforces standard oxygen titration.
BackgroundIncreased sympathetic nerve activity due to perioperative stress is associated with higher plasma catecholamine concentrations that lead to an increase in heart rate and blood pressure. This fact plays a pivotal role in the development of perioperative myocardial ischemia. A previous study in healthy volunteers has shown that the administration of supplemental oxygen attenuated sympathetic nerve activity, which was associated with lower plasma catecholamine concentrations. However, in patients undergoing surgery evidence is still lacking. We therefore tested the hypothesis that perioperative supplemental oxygen attenuates sympathetic nerve activity estimated by plasma catecholamines in patients at risk for cardiovascular complications undergoing major abdominal surgery.MethodsWe randomly assigned 81 patients to receive either 80% versus 30% inspired oxygen concentration throughout surgery and for the first two postoperative hours. We assessed noradrenaline, adrenaline and dopamine plasma concentrations as surrogate parameters for sympathetic nerve activity before induction of anesthesia, two hours after surgery and on the third postoperative day.Results41 patients received 80% oxygen and 40 patients received 30% oxygen. There was no significant difference in postoperative noradrenaline (effect estimated:-41.5 ng.L -1 , 95%CI -134.3, 51.2; p=0.38), adrenaline (effect estimated:11.2 ng.L -1 , 95%CI -7.6, 30.1; p=0.24) and dopamine (effect estimated:-1.61 ng.L -1 , 95%CI -7.2, 3.9; p=0.57) concentrations between both groups. ConclusionsWe found no significant difference in postoperative plasma catecholamine concentration between the 80% and 30% oxygen group in patients at risk for cardiovascular complications undergoing major abdominal surgery. Based on our results, it seems likely that supplemental oxygen did not influence sympathetic nerve activity in the perioperative setting.Trial RegistrationClinicalTrials.
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Taschner et al. (2021) conducted an RCT in Cardiovascular complications risk in major abdominal surgery (n=81). Supplemental oxygen vs. 30% inspired oxygen concentration was evaluated on Postoperative noradrenaline concentration (MD -41.5 ng.L-1, 95% CI -134.3, 51.2, p=0.38). Perioperative administration of 80% supplemental oxygen did not significantly affect postoperative plasma noradrenaline (MD -41.5 ng/L, p=0.38), adrenaline, or dopamine concentrations compared to 30% oxygen in patients at risk for cardiovascular complications undergoing major abdominal surgery.
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