Continuous versus bolus norepinephrine administration to treat hypotension after induction of general anaesthesia in low-to-moderate risk noncardiac surgery patients: a randomised trial

Kristen K Thomsen; Finn Külls; Christina Vokuhl; Linda Krause; Dominik Müller; Max Bossemeyer; Mirja Wegge; Alina Kröker; Alina Bergholz; Christian Zöllner; Daniel I Sessler; Bernd Saugel

doi:10.1016/j.bja.2025.03.017

Continuous versus bolus norepinephrine administration to treat hypotension after induction of general anaesthesia in low-to-moderate risk noncardiac surgery patients: a randomised trial

Br J Anaesth. 2025 May 2:S0007-0912(25)00195-3. doi: 10.1016/j.bja.2025.03.017. Online ahead of print.

Affiliations

¹ Department of Anesthesiology, Center of Anesthesiology and Intensive Care Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany; Outcomes Research Consortium®, Houston, TX, USA. Electronic address: science.thomsen@gmail.com.
² Department of Anesthesiology, Center of Anesthesiology and Intensive Care Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.
³ Institute of Medical Biometry and Epidemiology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.
⁴ Outcomes Research Consortium®, Houston, TX, USA; Center for Outcomes Research and Department of Anesthesiology, UTHealth, Houston, TX, USA.
⁵ Department of Anesthesiology, Center of Anesthesiology and Intensive Care Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany; Outcomes Research Consortium®, Houston, TX, USA.

PMID: 40318949
DOI: 10.1016/j.bja.2025.03.017

Abstract

Background: Hypotension after induction of general anaesthesia (postinduction hypotension) is common in patients undergoing noncardiac surgery and frequently requires treatment with vasopressors such as norepinephrine. We tested the hypothesis that giving norepinephrine continuously using a syringe infusion pump, compared with giving it as repeated manual boluses, reduces postinduction hypotension within 15 min after starting induction of general anaesthesia in low-to-moderate risk noncardiac surgery patients.

Methods: Patients undergoing elective noncardiac surgery were randomised to either continuous norepinephrine infusion or manual bolus norepinephrine administration intravenously during induction of general anaesthesia. In both groups, norepinephrine was administered through a peripheral venous catheter. Blood pressure was measured by clinicians using intermittent oscillometry. We additionally performed blinded continuous noninvasive blood pressure monitoring to quantify the duration and extent of postinduction hypotension. The primary endpoint was postinduction hypotension, defined as the area under a MAP of 65 mm Hg within 15 min after starting induction of general anaesthesia.

Results: From 276 randomised patients, 261 had complete data (median age: 62 yr; 40% female). The median (25th-75th percentile) area under a MAP of 65 mm Hg was 3.6 (0.0-16.6) mm Hg × min in patients assigned to continuous norepinephrine infusion, compared with 5.5 (0.5-24.5) mm Hg × min in patients assigned to manual bolus norepinephrine administration (P=0.070). The median duration of MAP values <65 mm Hg was 1.0 (0.0-2.5) min vs 1.4 (0.2-3.2) min (P=0.052).

Conclusions: Continuous administration of norepinephrine, compared with repeated manual bolus doses, did not reduce postinduction hypotension in low-to-moderate risk noncardiac surgery patients who had intermittent oscillometric blood pressure monitoring.

Keywords: anaesthesia induction; arterial pressure; cardiovascular dynamics; general anaesthesia; haemodynamic monitoring; norepinephrine; vasopressor.