Clinical Research Directory

Heart Rate Variability Changes and Postoperative Delirium After Major Abdominal Surgery

This prospective observational cohort study aims to investigate whether early postoperative changes in heart rate variability (HRV) relative to baseline are associated with the development of postoperative delirium (POD) in older patients undergoing elective major abdominal surgery under general anesthesia. Patients aged 65-85 years will be enrolled. Resting HRV will be measured at 10:00 AM on the day of surgery before anesthesia induction and at the same time point on the first postoperative day using a validated heart rate monitoring device. HRV parameters will be derived from standardized 5-minute recordings. Changes in HRV parameters from baseline will be calculated, and their associations with POD occurrence will be evaluated. Postoperative delirium will be assessed daily from 24 hours after surgery to postoperative day 7, using the 3-Minute Diagnostic Interview for Confusion Assessment Method (3D-CAM). The study will also explore the potential utility of HRV-derived markers for early POD risk stratification. Approximately 500 participants will be enrolled.

Maintaining Intraoperative Mean Arterial Pressure at 85 mmHg or Higher to Reduce Postoperative Delirium in Older Patients With Arterial Hypertension Having Non-cardiac Surgery

In older patients having surgery, postoperative delirium (an acute disturbance in awareness, attention, or cognition) is common and associated with short-term and long-term morbidity and mortality. The pathophysiology of postoperative delirium is multifactorial - but presumably includes inadequate brain perfusion during surgery caused by low intraoperative blood pressure. Therefore, the investigators aim to determine in a multicenter randomized-controlled trial if targeted intraoperative blood pressure management reduces postoperative delirium. The investigators will test the primary hypothesis that maintaining intraoperative mean arterial pressure at 85 mmHg or higher - compared to at 65 mmHg or higher (routine care) - reduces the incidence of postoperative delirium within the first 3 postoperative days in older patients with arterial hypertension having non-cardiac surgery. The investigators will also assess the duration of postoperative delirium, postoperative complications, and the patients' quality of life. The results of this trial will have a direct impact on guidelines and will help improve medical care for patients and the patients' health. Effective strategies to prevent postoperative delirium are missing. The hypothesis that targeted intraoperative blood pressure management can help reduce postoperative delirium is supported by previous observational studies and interventional trials. This trial is supposed to confirm the causal relationship between intraoperative blood pressure and postoperative delirium and to demonstrate the effectiveness of the therapeutic approach.

Effect of Eye Mask Use on Sleep Quality and Delirium After CABG Surgery

Coronary artery bypass graft (CABG) surgery is an effective treatment for coronary artery disease; however, sleep disturbances and delirium are common during the postoperative period and may adversely affect recovery. Environmental factors, particularly light exposure, can disrupt the sleep-wake cycle and contribute to poor sleep quality. Eye masks offer a simple, safe, and non-pharmacological method of reducing light exposure and supporting sleep. This study aims to determine the effect of eye mask use on sleep quality and delirium levels in patients following CABG surgery.

Perioperative Dezocine Administration and Postoperative Delirium in Elderly Cardiac Surgery Patients

Postoperative delirium (POD) is a common complication in elderly patients undergoing cardiac surgery and is associated with prolonged hospitalization, increased morbidity, and poor recovery. Currently, effective pharmacological strategies for preventing POD remain limited. This study aims to evaluate whether perioperative administration of dezocine can reduce the incidence of postoperative delirium in elderly patients undergoing cardiopulmonary bypass cardiac surgery. This is a prospective, randomized, controlled clinical trial conducted at Fuwai Hospital. Eligible patients aged 65 years or older undergoing elective cardiopulmonary bypass cardiac surgery will be randomly assigned to receive either dezocine or normal saline control in a 1:1 ratio. Patients in the dezocine group will receive intravenous dezocine (0.1 mg/kg) before anesthesia induction and again before transfer out of the operating room. At each administration time point, dezocine will be diluted with normal saline to a total volume of 6 mL and infused intravenously over 3 minutes. Patients in the control group will receive equivalent volumes of normal saline at the corresponding time points. The primary outcome is the incidence of postoperative delirium within 7 days after surgery. Secondary outcomes include delirium characteristics, postoperative recovery outcomes, pain scores, opioid consumption, sedation status, and perioperative complications. This study will investigate the potential role of dezocine as a preventive strategy for postoperative delirium in high-risk elderly cardiac surgery patients.

Preoperative Breathing Exercise Training and Postoperative Delirium After Robotic Radical Prostatectomy

Postoperative delirium is an acute and fluctuating disturbance in attention, awareness, and thinking that may occur after major surgery. Patients undergoing robot-assisted radical prostatectomy may be at risk because of factors such as older age, general anesthesia, prolonged surgery, pneumoperitoneum, and steep Trendelenburg positioning. This single-center, prospective, two-arm controlled pilot study will evaluate whether preoperative deep breathing exercise training is associated with a lower occurrence of postoperative delirium in patients undergoing elective robot-assisted radical prostatectomy. A total of 50 patients will be included, with 25 patients in the breathing exercise training group and 25 patients in the control group. Patients in the breathing exercise training group will receive standardized, device-free deep breathing exercise instruction during the preoperative period, usually approximately one week before surgery. They will be asked to perform three sessions per day until surgery, with 10 deep breaths in each session. Patients in the control group will receive routine preoperative information without additional structured breathing exercise training. Postoperative delirium will be assessed during the first 48 hours after surgery using the 4AT and Nursing Delirium Screening Scale (Nu-DESC). The study will also evaluate postoperative oxygenation, oxygen requirement, pain, nausea and vomiting, respiratory complications, intensive care requirement, and length of hospital stay. The study will not alter routine anesthesia, surgery, or postoperative treatment, and no additional invasive procedures, laboratory tests, or imaging will be performed for research purposes.

Cognitive Impact Associated With Surgery For Gastric Or Esophageal Cancer

The primary objective of this observational study is to investigate the incidence of Post Operative Delirium (POD) after gastroesophageal cancer surgery. Secondary objectives are to investigate the relationship between POD, preoperative depression, frailty, quality of life, malnutrition and sarcopenia. Participants identified with POD will be asked (at the routine follow-up meeting after surgery) to participate in an qualitative interview, in order to understand the participant's experience of postoperative delirium. The main objective aims to answer: What is the incidence of POD after gastroesophageal cancer surgery.

Impact of Intraoperative Hemodynamic Instability on Outcomes in Cardiac Surgery

Intraoperative hemodynamic instability (IOHI) is a common occurrence during cardiac surgery and is associated with organ hypoperfusion. However, the specific impact of IOHI on composite adverse outcomes remains unclear. This prospective cohort study aims to evaluate the association between intraoperative hemodynamic instability (defined as MAP \< 65 mmHg or vasopressor requirement) and major postoperative complications (Delirium, Acute Kidney Injury, Stroke, or Mortality) in adult patients undergoing elective cardiac surgery with cardiopulmonary bypass.

Intranasal Insulin for Postoperative Delirium in Older Patients With T2DM

Postoperative delirium (POD) is highly prevalent in older patients with type 2 diabetes mellitus (T2DM). Cerebral insulin resistance is considered a key pathophysiological mechanism underlying this association. This study aims to investigate whether intranasal insulin (INI) can prevent POD and early postoperative cognitive decline by improving cerebral insulin resistance. We will conduct a randomized, double-blind, placebo-controlled multicenter trial. Older T2DM patients will be randomly assigned to receive intranasal insulin at doses of 40 IU or 80 IU, or placebo. The primary objective is to evaluate the efficacy of INI in preventing POD and to determine the dose-response relationship.

Prediction and Prevention of Postoperative Mortality and Morbidity

This study will contribute to creating a prospective and automated preoperative risk assessment algorithm for predicting 30-day mortality, major adverse cardiac and cerebrovascular events (MACCE), and postoperative neurocognitive outcomes following elective cardiac and vascular surgery in older adults. It will evaluate associations between perioperative factors and longer-term neurocognitive outcomes, including postoperative neurocognitive disorder and dementia. In addition, this study will assess scalable, multimodal preoperative and intraoperative interventions to improve perioperative outcomes. This study will explore two main hypotheses: 1. Preoperative personalized prehabilitation with proactive cognitive and behavioral interventions will improve postoperative cognitive outcomes, morbidity, and mortality in high-risk elderly surgical patients. 2. Proactive bundled intraoperative interventions are superior to reactive standard of care in reducing postoperative cognitive outcomes, MACCE, and mortality. Expected Outcome: Improved EHR algorithm will have higher predictive accuracy for MACCE and mortality while predicting postoperative cognitive outcomes.

Effects of Ciprofol on Postoperative Delirium and Outcomes in Elderly Patients Undergoing Major Thoracic Surgery

There are many factors that make elderly patients prone to POD. On the basis of these factors, surgery and anesthesia can increase the incidence of POD in elderly patients. Deep depth of intraoperative anesthesia and persistent hypotension may increase the risk of POD occurrence in elderly patients. So far, no specific POD prevention method has been found. In recent years, a large number of studies on POD have brought forward more new views on its pathogenesis, prevention and treatment. There is insufficient evidence to recommend specific anesthetic agents and dosages to reduce the risk of POD in elderly patients, and only low-quality evidence to recommend propofol. At present, it is considered that the best way to reduce postoperative delirium is perioperative risk management, to evaluate high-risk patients or patients undergoing high-risk surgery as extensive as possible, and to quantify their risk of postoperative delirium. Effective measures include depth management of anesthesia, multi-modal analgesia management, and optimization of drug intervention. Ciprofol is a class 1 innovative drug independently developed by China and with global independent intellectual property rights. Ciprofol has been widely used in anesthesiology and critical care medicine. The pre-market phase I-III and post-market data showed that during the induction and maintenance of general anesthesia, Ciprofol had less impact on hemodynamics and more stable anesthesia depth than propofol. Relevant studies have shown that Ciprofol can reduce the risk of hypotension, and can provide better brain oxygenation and more stable intraoperative hemodynamics than propofol. At present, the influence of different sedative drugs on POD incidence in elderly patients remains to be studied. Therefore, we will apply Ciprofol or propofol in elderly patients undergoing thoracic surgery to observe their influence on POD incidence and provide reference for clinical use.

Ketofol Versus Ketodex for POD Prophylaxis in Elderly Cancer Surgery

Postoperative delirium (POD) is a common and serious neurocognitive complication after surgery, particularly in elderly patients undergoing major cancer surgeries. It is associated with prolonged hospital stay, impaired quality of life, increased postoperative cognitive dysfunction, and higher mortality. The pathophysiology of POD is multifactorial and involves neuroinflammation, oxidative stress, impaired cerebral perfusion, and neurotransmitter imbalance. Several anesthetic agents have been investigated for their potential neuroprotective effects against POD. Ketamine, through NMDA receptor antagonism, may reduce neuroinflammation and provide hemodynamic stability and opioid-sparing analgesia, although concerns remain regarding hallucinations and psychomimetic effects. Propofol, acting through GABA receptor activation, may protect against oxidative neuronal injury but may also induce hypotension in elderly patients. Dexmedetomidine, a selective α2-adrenergic agonist, has shown promising sedative, analgesic, and anti-inflammatory properties with potential protective effects against POD, although bradycardia and uncertainty regarding optimal dosing remain concerns. Combinations such as ketofol (ketamine-propofol) and ketodex (ketamine-dexmedetomidine) may provide synergistic benefits by improving hemodynamic stability, analgesia, and sedation while minimizing adverse effects. Previous studies have demonstrated favorable perioperative outcomes with both combinations; however, direct comparisons regarding their role in preventing postoperative delirium in elderly patients undergoing pelvi-abdominal cancer surgeries remain limited. Therefore, this study aims to compare the efficacy and safety of ketofol versus ketodex as prophylactic strategies against POD in this high-risk population.

Sex-Dependent Risk of Postoperative Delirium and Mediating Effects of Family Visits

Postoperative delirium is a common and serious complication after surgery, affecting 10-40% of older patients undergoing non-cardiac procedures. It is characterized by sudden changes in attention, awareness, and thinking that fluctuate throughout the day. Delirium is associated with longer hospital stays, higher mortality, worse long-term brain function, and substantially increased healthcare costs. While several risk factors are known, it remains unclear whether a patient's sex independently influences the risk of developing postoperative delirium, as existing studies have produced conflicting results and were often not designed to specifically examine sex differences.Family visitation is a promising non-drug approach to preventing delirium. Studies in intensive care patients have shown that those who receive family visits have a significantly lower risk of developing delirium. However, it is unknown whether men and women receive different amounts of family visits after surgery, and whether any such difference could help explain sex-based disparities in delirium risk. Given that traditional gender roles in caregiving persist, women - who often serve as primary caregivers in their families - may receive fewer visits when they themselves become patients.This prospective observational study led by the University of Zurich will enroll 471 patients aged 65 years or older undergoing non-cardiac surgery lasting at least 2 hours under general or spinal anesthesia. The primary aim is to determine whether female patients have a higher risk of developing postoperative delirium within three days after surgery compared to male patients. Delirium will be assessed twice daily using the 4 A's Test (4AT), a validated and standardized screening tool. The secondary aim is to evaluate whether female patients receive fewer family visits than male patients and whether any difference in visitation mediates the sex-dependent delirium risk. Family visits will be recorded using an anonymous sign-in sheet placed in the patient's room. The study does not involve any experimental interventions; all patients receive standard clinical care. Participation is voluntary, and withdrawal is possible at any time without affecting medical treatment.

MInimizing Delirium With Nasal Dexmedetomidine-InducEd Sleep (MIDDIES)

This study aims to determine whether, compared with placebo, the nighttime self-administration of a nasal dexmedetomidine is effective at inducing sleep and preventing postoperative delirium in high-risk patients.

Impact of Sevoflurane Versus Propofol on Postoperative Delirium in Elderly Diabetic Patients Undergoing Non-Cardiac Surgery: a Multicenter, Randomized Controlled Trial

The present study is a multicenter， randomized controlled clinical trial, which plans to enroll 450 diabetic patients aged more than 60 years. The participants will be randomly assigned in a 1:1 ratio and will receive either propofol or sevoflurane for intraoperative anesthesia maintenance to evaluate the impact of these two anesthetic drugs on postoperative delirium. The aim of our study is to explore whether the use of propofol for anesthesia maintenance in elderly diabetic patients undergoing elective non-cardiac major surgery can reduce the incidence of postoperative delirium. This study will provide new perspectives for improving perioperative management in elderly diabetic patients and optimizing anesthesia management strategies to reduce the risk of postoperative delirium.

Elderly Patients Undergoing Surgery During Perioperative Period

The elderly patients have poorer overall conditions and have lower tolerance to trauma, anesthesia, and surgery. Therefore, the incidence of postoperative complications is relatively higher. In non-cardiac surgeries, approximately 20% of elderly patients experience postoperative complications, and the incidence of postoperative delirium (POD) is 23.8%. This may lead to prolonged hospital stays, increased hospital costs, and affect prognosis and even mortality. The investigators plan to conduct a prospective cohort study by systematically collecting biological samples and clinical information of elderly patients during the perioperative period to explore the possible risk factors and pathogenesis of postoperative delirium and postoperative complications in elderly surgical patients, and to construct a risk prediction model for postoperative complications.

Comparison of Target-Controlled and Manual Total Intravenous Anesthesia in Supratentorial Surgery

This study aims to investigate the effect of target-controlled infusion using the Eleveld pharmacokinetic model compared with manually controlled total intravenous anesthesia on the incidence of postoperative delirium in patients undergoing supratentorial surgery. Propofol and remifentanil are administered using either target-controlled or manual infusion techniques according to the study protocol. Secondary objectives include comparisons of intraoperative anesthetic consumption, hemodynamic responses, recovery profiles, postoperative pain, and postoperative nausea and vomiting between the two anesthesia strategies. The study seeks to evaluate whether target-controlled infusion provides improved anesthetic management and postoperative outcomes compared with manual total intravenous anesthesia.

A Phase II Clinical Two-Stage Study of Transcranial Magnetic Stimulation in Preventing Postoperative Delirium in Elderly Patients After Urological Surgery

Cases were included based on the inclusion and exclusion criteria, and induction, maintenance, and recovery were conducted in accordance with the standard protocol for general anesthesia. After tracheal intubation and before tracheal tube removal at the end of the surgery, the parameters for iTBS stimulation frequency and duration were as follows: intensity was 80% of the active movement threshold, with 3 pulses per cluster at 50Hz, a frequency of 5Hz, 30 clusters of 10 pulses each, an 8 - second interval, and a single 600 - pulse; the 8 - shaped coil was connected to the electrodes in the designated head area (left frontal lobe cortex).Observation contents: Whether there is postoperative delirium and its severity: 3D - CAM assessment scale, DMAS assessment scale; awakening time, extubation time, PACU stay time, hospital stay time; 1 - 7 days after surgery or before discharge, POD assessment and pain - sleep assessment, the first time getting out of bed; postoperative complications; adverse reactions; adverse events, and so on.

Effect of Transcutaneous Auricular Vagus Nerve Stimulation on Postoperative Delirium and Negative Emotions in Patients Undergoing Cardiac Surgery

A multicenter, randomized, double-blind, sham-controlled trial to investigate the effects of intraoperative transcutaneous auricular vagus nerve stimulation (taVNS) on the incidence of postoperative delirium and negative emotional states (anxiety, depression) in patients undergoing elective cardiac surgery.

Proactive Temperature Management in CRS-HIPEC for Prevention of Delirium

This randomized controlled trial evaluates the efficacy of a proactive Goal-Directed Temperature Management (GDTM) protocol in reducing postoperative delirium among patients undergoing Cytoreductive Surgery (CRS) with Hyperthermic Intraperitoneal Chemotherapy (HIPEC) for pseudomyxoma peritonei. CRS-HIPEC presents a unique physiological challenge characterized by a biphasic thermal trajectory: potential hypothermia during extensive surgery followed by rapid iatrogenic hyperthermia during perfusion. This study compares a standardized GDTM strategy-which incorporates strict normothermia maintenance and anticipatory pre-cooling prior to perfusion-against standard reactive thermal management. The primary objective is to determine if optimized thermoregulation can attenuate thermal variability and improve early neurocognitive recovery.

GENECARD - the Use of Genetic, Epigenetic, Metabolomic, Proteomic and Microbiotic Markers, Image and Voice Biomarker Analyses, and Pre- and Intraoperative Clinical Data - to Predict Early Complications After Cardiac Surgery.

The goal of this observational cohort study is to prove whether genetic, epigenetic, transcriptomic, proteomic, metabolomic, imaging, voice, and clinical markers can improve prediction of early complications after cardiac surgery in adult patients. The main questions it aims to answer are: Which biological and clinical markers are associated with: new-onset atrial fibrillation (NOAF), acute kidney injury (AKI), postoperative delirium (POD), vasoplegia, postoperative bleeding and 30-day mortality? Can combining these markers improve early prediction of postoperative complications compared with current clinical risk scores? Researchers will analyze a wide range of data collected before, during, and after cardiac surgery and compare patients who develop early complications with those who do not to identify risk factors and early biomarkers. Participants will: Provide biological samples (blood, urine, stool) before and after surgery for genetic, epigenetic, transcriptomic, proteomic, metabolomic, microbiome, and laboratory testing. Undergo standard preoperative and intraoperative imaging and clinical assessments. Allow collection of clinical data related to postoperative outcomes (For some participants) have voice and video recordings performed to help identify early signs of postoperative delirium. This study aims to improve early detection of postoperative complications and support development of personalized diagnostic and treatment strategies for patients undergoing cardiac surgery.

Electroencephalogram Characteristics of Surgical Anesthetized Patients and Postoperative Dilirium

Objective: To construct a perioperative EEG database for elderly patients under general anesthesia and to explore the relationship between their EEG spectrum characteristics and the occurrence and severity of postoperative delirium. Content: This study aims to investigate elderly patients undergoing elective orthopedic surgery under general anesthesia with endotracheal intubation, analyze the changes in the perioperative EEG spectrum and its correlation with the occurrence of postoperative delirium, and explore the relationship between perioperative EEG changes and the occurrence of postoperative delirium. Methods: Patients aged 60 years or older who were scheduled to undergo orthopedic joint replacement or spinal surgery and had a hospital stay of more than 2 days were selected. All patients underwent MMSE and 3D-CAM assessment before surgery. Before anesthesia induction, anesthesia depth monitoring electrodes were placed on the patient\&#39;s occipital or frontal temporal region, and EEGs were collected in awake and quiet states, under general anesthesia, and during anesthesia recovery. In the PACU, the score was calculated based on the CAM-ICU scale. The patients were assessed with the 3D-CAM scale for awakening once a day at 15:00-20:00 the day before surgery, and twice a day at 9:00-11:00 and 15:00-20:00 during 1-5 days after surgery, or at any time when obvious delirium symptoms appeared, unless discharged from the hospital or taking sedatives (RASS\&lt;-3). Ten minutes after the assessment, the occipital EEG was monitored when the patient was conscious and quiet, or when obvious delirium appeared. According to the test results of the 3D-CAM scale, it was determined whether the patient had postoperative delirium, and the patients were divided into the delirium group and the non-delirium group. The EEG characteristics of the two groups of patients were analyzed before, during, and after surgery. Research significance: The results of this study can provide objective indicators and theoretical basis for monitoring and diagnosing the occurrence and development of POD, which can help clinicians to identify patients with increased risk of delirium at an early stage, adjust the plan in time, and change the triggering risk factors of POD.

Venous Congestion And Delirium After Cardiac Surgery

Postoperative delirium (POD) is an acute brain dysfunction characterized by inattention, impaired consciousness, and cognitive and orientation disturbances, and is a common complication after cardiac surgery. The high incidence of up to 52% of POD in cardiac surgery patients lead to a range of adverse clinical outcomes.The brain tissue is enclosed in a rigid anatomical structure; when there is an obstruction to venous return from the brain, intracranial pressure can increase, and blood supply to the brain tissue can decrease, leading to central nervous system dysfunction. Systemic venous congestion can occur when there is right heart dysfunction or excessive volume load. When right heart failure and/or volume overload occurs, changes in right atrial pressure are transmitted to the venous system of organs throughout the body, with dilatation of the inferior vena cava (IVC), obstruction of blood return from the hepatic, portal, and renal veins, and abnormal venous flow signals and altered ultrasound Doppler flow patterns. The primary objective of this prospective cohort study is to explore if intraoperative systemic venous congestion is associated with POD after cardiac surgery. This study will also investigate the relationship between intraoperative systemic venous congestion and postoperative complications, and the relationship between each separate venous congestion and POD after cardiac surgery.

Prospective Randomized Controlled Trial of VR Cognitive Training in Reducing Postoperative Delirium in Elderly Patients With Cerebral Small Vessel Disease Undergoing Non-Cardiac Surgery

This clinical study investigates whether virtual reality (VR)-based cognitive training can help prevent postoperative delirium (POD) in elderly non-cardiac patients with pre-existing cerebral small vessel disease (CSVD). With the global aging population undergoing more surgical procedures, POD has emerged as a serious complication in surgical patients that can prolong hospital stays and increase the risk of developing Alzheimer's disease. The study utilizes an innovative VR system that combines eye-tracking cognitive assessment with interactive rehabilitation games to evaluate and train patients' cognitive function before non-cardiac and non-intracranial operations. Conducted at Peking University Third Hospital and First Hospital, this research specifically targets patients undergoing general surgery, orthopedic surgery and other non-intracranial/non-cardiac procedures to determine if this technology-based intervention can effectively reduce POD incidence in this population while exploring its underlying mechanisms. The findings could lead to a practical solution for protecting cognitive health in elderly patients undergoing routine surgical procedures during recovery

The Study of Postoperative Delirium and Glymphatic System Function in Cardiac Surgery

Postoperative delirium after cardiac surgery is an acute cerebral dysfunction characterized by inattention, impaired consciousness, and cognitive and orientation disturbances. It manifests clinically as acute onset, severe neurocognitive impairment, and periodic fluctuating progression, and is one of the most common complications after major cardiac and vascular surgery. It typically occurs within one week after surgery, with a peak incidence at 24 hours postoperatively. Due to differences in the basic characteristics of study populations and assessment tools, the reported incidence of postoperative delirium after cardiac surgery varies significantly, ranging from 14% to 50%. Postoperative delirium not only prolongs patients' ICU and hospital stays, increases medical costs, and raises short-term and long-term mortality rates, but is also closely associated with long-term cognitive impairment, dementia, and a decline in activities of daily living. The pathophysiology of delirium is complex and may be caused by a combination of multiple factors, including microembolism, ischemia-reperfusion injury, and systemic inflammatory response. Since the mechanisms underlying delirium are not yet fully understood, effective treatments are currently lacking. Postoperative delirium after cardiac surgery is a significant clinical challenge for medical teams. The brain is distinct from other organs, as the tight junctions of the blood-brain barrier isolate the exchange between the brain, cerebrospinal fluid, blood, and extracellular fluid. For a long time, it was believed that the brain lacks a lymphatic system, and the extracellular fluid in brain tissue was considered stagnant. The lack of fluid flow can lead to the accumulation of protein waste, which is very detrimental to brain health. The glymphatic system is a major update in the anatomical knowledge of the central nervous system in recent years. It is a highly organized fluid transport system within the human brain, with the primary function of promoting convective exchange between the interstitial fluid of the central nervous system and cerebrospinal fluid. The main physiological function of the glymphatic system is to clear metabolic waste and large-molecule solutes, thereby maintaining central homeostasis; it also acts as a communicator between the brain and peripheral immunity, ensuring that the central nervous system is not overlooked by the immune system. Additionally, the glymphatic system helps deliver nutrients to the brain, such as glucose, lactate, and amino acids. Dysfunction of the glymphatic system is associated with various neurological diseases, such as Alzheimer's disease and Parkinson's disease, and related research has become a frontier and hotspot in the field of neuroscience. Dysfunction of the glymphatic system leads to the accumulation of β-amyloid and tau proteins in the brain, which cannot be cleared, and is one of the pathogenic mechanisms of Alzheimer's disease. There is a strong bidirectional association between Alzheimer's disease and delirium. Patients with Alzheimer's disease-related dementia are 2.5 to 4.7 times more likely to experience delirium, and the incidence of newly diagnosed Alzheimer's disease-related dementia in patients with delirium increases by 12.5 times. However, the underlying mechanisms of postoperative delirium remain unclear, which has motivated our investigation into the causal relationship between the glymphatic system and postoperative delirium. From a theoretical perspective, chronic dysfunction of the glymphatic system signifies brain vulnerability and a higher incidence of neurological diseases. If subjected to surgical stress, sudden dysfunction may represent acute glymphatic system insufficiency. With the rapid development of clinical imaging tools, functional MRI is a non-invasive method for assessing glymphatic system function, bringing possibilities to clinical research. Therefore, this study aims to explore the association between postoperative delirium after cardiac surgery and the glymphatic system, in order to deepen the understanding of glymphatic system function and investigate the mechanisms of postoperative delirium after cardiac surgery, and to provide ideas for new interventions for postoperative delirium after cardiac surgery.