The Effect of Noradrenaline Infusion Versus Standard Blood Pressure Management on Perioperative HYPotension in NOn-caRdiac Surgery HYP-NOR Trial

A single concentration of noradrenaline (10 μg/ml) will be initiated 15-60 seconds prior to the induction of anaesthesia, then titrated and maintained until 4 hours after surgery to meet pre-specified mean arterial pressure (MAP) targets. The drug infusion will be started at a dose of 0.01 μg/kg/min and will be titrated to a maximum of 0.1 μg/kg/min. Anaesthesiologists will be advised to use the lowest possible dose of noradrenaline. Avoidance of MAP decreases of \>20% from baseline values or \<60-70 mm Hg will be required in both groups. Individual baseline MAP value will be defined as resting blood pressure obtained in at least two measurements at the surgery ward on the day before surgery. Noradrenaline will be administered peripherally in all patients who do not have a central venous catheter in place.

Patients in the control group will receive standard blood pressure management reactive to blood pressure values. In the light of the current ESA/ESC 2022 guidelines, all patients in the control group will be treated to avoid MAP \<60-70 mm Hg. Ephedrine boluses (5 mg each, up to 25 mg total intravenous dose) will be recommended as a first-line hypotension treatment. Subsequent treatment will involve administering peripheral noradrenaline. Notwithstanding, there is a variation in clinical practice regarding the choice and timing of vasopressors and fluids to be administered during and after surgery, therefore, hypotension treatment will not be further protocolized to increase the feasibility and generalizability of the trial.