Postoperative cognitive complications are a major concern in older surgical patients. The trial protocol addresses the clinical question of whether the choice of vasoactive agent used to treat intraoperative hypotension influences the risk of postoperative delirium. Specifically, the investigators compare two commonly used vasopressors/vasoactive drugs — phenylephrine and ephedrine — when administered as continuous intravenous infusions to maintain blood pressure during general anaesthesia for major non-cardiac, non-neurosurgical procedures.
The rationale stems from uncertainty in perioperative practice about whether pharmacologic differences between agents that primarily increase vascular tone versus those with mixed inotropic and vasoconstrictive effects might differentially affect cerebral perfusion and hence delirium risk in elderly patients. The protocol aims to generate high-quality evidence to inform strategies for intraoperative blood pressure management in this vulnerable population.
This is a multicentre, randomized, double-blind, controlled trial. The study will be conducted at seven hospitals in China. The protocol and trial details are reported in Annals of Medicine with registration recorded in the Chinese Clinical Trial Registry (ChiCTR2500115385). The publication lists the trial as a randomized controlled, comparative, multicenter study.
The trial will enrol a total of 1,084 elderly patients scheduled for elective major surgery under general anaesthesia. The population is described using MeSH indexing that includes Aged and Aged, 80 and over, indicating the focus on older patients. Inclusion and exclusion criteria, detailed demographic criteria, and specific comorbidity exclusions are not reported in the abstract provided by the source.
Participants will be randomized in a 1:1 ratio to one of two intervention arms and randomization will be stratified by study centre. The trial is double-blind: neither participants nor the clinical investigators assessing outcomes will know allocation. The abstract does not provide the randomization method, allocation concealment procedure, or code-breaking conditions; those details were not reported in the source abstract.
Patients randomized to either arm will receive a continuous intravenous infusion of the assigned drug — phenylephrine or ephedrine — during surgery. The infusion will be used to maintain mean arterial pressure (MAP) within 20% of the patient’s baseline value. The abstract specifies this MAP target but does not provide specific starting infusion rates, titration algorithms, co-interventions, or rescue therapy protocols; such protocol elements were not reported in the abstract.
Primary outcome
Secondary outcomes
The source does not provide the specific delirium assessment instruments, thresholds for severity grading, or the schedule and personnel responsible for outcome assessment; these procedural details were not reported in the abstract.
The investigators hypothesize that intraoperative management of hypotension with ephedrine, compared with phenylephrine, will reduce the incidence of postoperative delirium in elderly patients undergoing major non-cardiac and non-neurosurgical surgery. If confirmed, the results could influence choice of vasoactive agent during anaesthesia and inform guidelines for intraoperative blood pressure management to reduce delirium risk in older adults.
The trial is framed as addressing a clinically important gap: whether pharmacologic selection for blood pressure support can modify postoperative cognitive outcomes.
The trial is registered in the Chinese Clinical Trial Registry under ChiCTR2500115385. The protocol is published in Annals of Medicine (Ann Med) with PMID 42745683 and DOI 10.1080/07853890.2026.2732555; the abstract indicates electronic publication on 2026 Sep 16 with print citation in 2026 Dec;58(1):2732555.
Note on source limitations
The source material for this rewrite is the PubMed/NCBI abstract. It provides study aims, design, primary and secondary endpoints, sample size, setting, and registration number, but does not include detailed eligibility criteria, dosing regimens, monitoring protocols, safety oversight arrangements, statistical analysis plans, or results. Those elements would be available in the full trial protocol or subsequent trial reports but were not reported in the abstract.