Effect of different durations of preoperative computerised cognitive training on postoperative delirium in older patients undergoing cardiac surgery: a study protocol for a prospective, randomised controlled trial.

Introduction: Postoperative delirium (POD) is a common neurological complication after surgery among older patients, characterised by acute disturbances in consciousness, attention and cognition, usually occurring within 24-72 hours after surgery. POD has a significant impact on the prognosis of older patients undergoing major cardiovascular surgery, including increased length of hospital stay, hospital costs and readmission rates, with an incidence rate as high as 26%-52%. Computerised cognitive training (CCT) refers to difficulty-adaptive training in cognitive domains such as attention, memory and logical reasoning, using systematically designed tasks. Existing studies have shown that CCT has reduced the risk of delirium in non-cardiac surgery patients with at least minimal compliance. The purpose of this study is to investigate the effects of preoperative CCT on the incidence of POD in older patients undergoing elective cardiac surgery, to clarify the dose-effect relationship between different training time of preoperative CCT and POD and to explore the minimum effective time target that can significantly lower the incidence of POD.

Methods and analysis: This is a prospective, single-blind, randomised controlled trial that aims to enrol 261 older patients scheduled for elective cardiac surgery at the Affiliated Hospital of Xuzhou Medical University. The patients will be randomised into three groups: group C will be the routine care group (no CCT prior to surgery); group L will be the low-dose time group (with a total of 5 hours of CCT prior to surgery) and group H will be the high-dose time group (with a total of 10 hours of CCT prior to surgery). The primary outcome is the incidence of delirium within 7 days after surgery. Secondary outcomes include postoperative mild neurocognitive disorder (NCD) and postoperative major NCD (30 days up to 1 year), time of onset and duration and severity of delirium, and all-cause mortality within 1 year after surgery. The results of this study are of significant importance for establishing effective, patient-centred and low-risk prevention strategies for POD/postoperative NCD.

Ethics and dissemination: This study protocol has been approved by the Ethics Committee of the Affiliated Hospital of Xuzhou Medical University (Ethics Number: XYFY2023-KL149-01). All participants will provide written informed consent, and the results of the study will be published in international peer-reviewed academic journals and presented at academic conferences.

Trial registration number: ChiCTR2300072806.