A randomised controlled trial of dexmedetomidine for delirium in adults undergoing heart valve surgery

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.

Effects of dexmedetomidine on renal function after cardiac surgery for infective endocarditis: An interim analysis of a randomized controlled trial

BACKGROUND

Patients undergoing cardiac surgery for infective endocarditis (IE) are at a high risk of postoperative acute kidney injury (AKI) owing to heightened systemic inflammation. Therefore, we aimed to investigate the effect of dexmedetomidine on postoperative AKI in patients who underwent cardiac surgery for IE.

METHODS

A total of 63 patients who underwent cardiac surgery for IE were randomly assigned to receive either intravenous dexmedetomidine infusion of 0.4 μg kg-1 h-1 (DEX group) or normal saline infusion (control group) for 24 h after induction of anesthesia. The occurrence of AKI within seven days postoperation, epinephrine, norepinephrine, and interleukin-6 levels, as well as postoperative morbidities, were assessed. An intertrim analysis was conducted using Pocock's alpha spending function at α = 0.05 and β = 0.2.

RESULTS

This trial was early terminated according to the results of interim analysis performed when 60 % of the pre-set number of patients have been collected. The incidence of AKI was significantly lower in the DEX group than in the control group (32.3 % vs. 9.4 %, p = 0.025). Patients in the DEX group had significantly lower epinephrine levels than those in the control group, whereas norepinephrine and interleukin-6 levels were similar. Perioperative mean arterial pressure or heart rate did not differ between the groups.

CONCLUSIONS

Dexmedetomidine administration for 24 h starting from induction of anesthesia significantly reduced the incidence of postoperative AKI after cardiac surgery for IE (by 29 % vs. control) without hemodynamic side effects. This was accompanied by a significant attenuation of postoperative increase in serum epinephrine levels.

The effect of perioperative dexmedetomidine on postoperative delirium in adult patients undergoing cardiac surgery with cardiopulmonary bypass: a systematic review and meta-analysis of randomized controlled trials

BACKGROUND

Dexmedetomidine is considered to have neuroprotective effects and may reduce postoperative delirium in both cardiac and major non-cardiac surgeries. Compared with non-cardiac surgery, the delirium incidence is extremely high after cardiac surgery, which could be caused by neuroinflammation induced by surgical stress and CPB. Thus, it is essential to explore the potential benefits of dexmedetomidine on the incidence of delirium in cardiac surgery under CPB.

METHODS

Randomized controlled trials studying the effect of perioperative dexmedetomidine on the delirium incidence in adult patients undergoing cardiac surgery with CPB were considered to be eligible. Data collection was conducted by two reviewers independently. The pre-specified outcome of interest is delirium incidence. RoB 2 was used to perform risk of bias assessment by two reviewers independently. The random effects model and Mantel-Haenszel statistical method were selected to pool effect sizes for each study.

RESULTS

PubMed, Embase, Cochrane Library, and Web of Science were systematically searched from inception to June 28, 2023. Sixteen studies including 3381 participants were included in our systematic review and meta-analysis. Perioperative dexmedetomidine reduced the incidence of postoperative delirium in patients undergoing cardiac surgery with CPB compared with the other sedatives, placebo, or normal saline (RR 0.57; 95% CI 0.41-0.79; P = 0.0009; I2 = 61%).

CONCLUSIONS

Perioperative administration of dexmedetomidine could reduce the postoperative delirium occurrence in adult patients undergoing cardiac surgery with CPB. However, there is relatively significant heterogeneity among the studies. And the included studies comprise many early-stage small sample trials, which may lead to an overestimation of the beneficial effects. It is necessary to design the large-scale RCTs to further confirm the potential benefits of dexmedetomidine in cardiac surgery with CPB.

REGISTRATION NUMBER

CRD42023452410.

Mapping Theme Trends and Research Frontiers in Dexmedetomidine Over Past Decade: A Bibliometric Analysis

Background

Dexmedetomidine, an α2-adrenergic receptor (α2-AR) agonist, is extensively used in clinical and animal studies owing to its sedative, analgesic, and anxiolytic effects. The diverse range of research domains associated with dexmedetomidine poses challenges in defining pivotal research directions. Therefore, this study aimed to conduct a qualitative and quantitative bibliometric study in the field of dexmedetomidine over the past decade to establish current research trends and emerging frontiers.

Methods

Relevant publications in the field of dexmedetomidine between 2014 and 2023 were extracted from the Web of Science Core Collection database. The bibliometric analysis, incorporating statistical and visual analyses, was conducted using CiteSpace (6.1.R6) and R (4.3.1).

Results

The present study encompassed a total of 5,482 publications, exhibiting a consistent upward trend over the past decade. The United States and its institutions had the highest centrality. Ji, Fuhai, and Ebert, Thomas J. were identified as the most productive author and the most cited author, respectively. As anticipated, the most cited journal was Anesthesiology. Moreover, cluster analysis of cited references and co-occurrence of keywords revealed that recent studies were primarily focused on sedation, delirium, and opioid-free anesthesia. Finally, a timeline view of keywords clusters and keywords burst demonstrated that primary research frontiers were stress response, neuroinflammation, delirium, opioid-free anesthesia, peripheral nerve block, and complications.

Conclusion

Current research trends and directions are focused on sedation, delirium, and opioid-free anesthesia, as evidenced by our results. The frontier of future research is anticipated to encompass basic investigations into dexmedetomidine, including stress response and neuroinflammation, as well as clinical studies focusing on delirium, opioid-free anesthesia, peripheral nerve block, and associated complications.

The effectiveness of dexmedetomidine for preventing acute kidney injury after surgery: a systematic review and meta-analysis

Background

Postoperative acute kidney injury (AKI) is a serious and distressing complication connected to various adverse outcomes following the surgical operation. Controversy remains regarding the dexmedetomidine's preventive impact on postoperative AKI. Therefore, this investigation aims to explore the efficiency and safety of dexmedetomidine in preventing AKI after surgical operation.

Methods

We systematically searched electronic databases such as PubMed, Embase, Web of Science, and the Cochrane Library to detect eligible randomized controlled studies that used dexmedetomidine for the prevention of AKI following operation up to April 30, 2023. The main outcome evaluated was AKI incidence. The evidence quality was assessed employing the Grading of Recommendations Assessment, Development, and Evaluation.

Results

The meta-analysis included 25 trials, including 3,997 individuals. Of these, 2,028 were in the dexmedetomidine group, and 1,969 were in the control group. The result showed that patients administered dexmedetomidine significantly decreased the AKI incidence following surgical operation in contrast to the control group (risk ratio, 0.60; 95% confidence intervals, 0.45-0.78; p < 0.05; I 2 = 46%). In addition, dexmedetomidine decreased the period of hospitalization in both the intensive care unit (ICU) and the hospital while also reducing postoperative delirium (POD) occurrence. However, dexmedetomidine elevated the incidence of bradycardia but did not have a significant impact on other indicators.

Conclusion

Our meta-analysis indicates that the dexmedetomidine treatment reduces the postoperative AKI and POD risk while also shortening the time of hospitalization in the ICU and hospital. However, it is connected to an increased bradycardia risk.

Effect of percutaneous cerebral oximetry-guided anaesthetic management on postoperative delirium in older adults undergoing off-pump coronary artery bypass grafting: study protocol for a single-centre prospective randomised controlled trial in a tertiary academic hospital in China

INTRODUCTION

Postoperative delirium is a prominent and clinically important complication in older adults after coronary artery bypass grafting (CABG) surgery, resulting in prolonged hospital stay, long-term cognitive impairment and increased morbidity and mortality. Many studies have shown that cerebral desaturation is associated with increased risk of postoperative delirium during on-pump cardiac surgery. However, few studies have focused on the effect of optimising regional cerebral oxygen saturation (rSO2) on postoperative delirium during off-pump CABG. The purpose of this study is to investigate whether intraoperative anaesthetic management based on percutaneous cerebral oximetry monitoring decreases the incidence of postoperative delirium in older adults undergoing off-pump CABG.

METHODS

This single-centre randomised controlled trial will randomly assign 200 patients to the intervention group or the control group at a ratio of 1:1. The patients in the intervention group will be observed by percutaneous cerebral oximetry monitoring that the desaturation (a drop of more than 20% from baseline value or rSO2 less than 55% for >60 consecutive seconds at either probe) during the procedure triggered the intervention strategies, while the cerebral oximetry data of the control group will be hidden from the clinical team and patients will be anaesthetised by the usual anaesthetic management. The primary outcome will be the incidence of postoperative delirium during the first 7 days after off-pump CABG. Delirium will be comprehensively evaluated by the combination of the Richmond Agitation Sedation Scale and the Confusion Assessment Method for the intensive care unit. The secondary outcomes will include the incidence of postoperative acute kidney injury and myocardial infarction during the hospital stay, as well as the intensive care unit and hospital length of stay.

ETHICS AND DISSEMINATION

This study was approved by the Ethics Committee of the Chinese Academy of Medical Sciences, Fuwai Hospital (No 2022-1824). Written informed consent will be obtained from each patient or their legal representatives before enrolment. The results of this trial will be published in an international peer-reviewed scientific journal.

TRIAL REGISTRATION NUMBER

ChiCTR2300068537.

Effects of dexmedetomidine on kidney and brain tissue microcirculation and histology in ovine cardiopulmonary bypass: a randomised controlled trial

Cardiac surgery requiring cardiopulmonary bypass is associated with postoperative acute kidney injury and neurocognitive disorders, including delirium. Intra-operative inflammation and/or impaired tissue perfusion/oxygenation are thought to be contributors to these outcomes. It has been hypothesised that these problems may be ameliorated by the highly selective α2 -agonist, dexmedetomidine. We tested the effects of dexmedetomidine on renal and cerebral microcirculatory tissue perfusion, oxygenation and histology in a clinically relevant ovine model. Sixteen sheep were studied while conscious, after induction of anaesthesia and during 2 h of cardiopulmonary bypass. Eight sheep were allocated randomly to receive an intravenous infusion of dexmedetomidine (0.4-0.8 μg.kg-1 .h-1 ) from induction of anaesthesia to the end of cardiopulmonary bypass, and eight to receive an equivalent volume of matched placebo (0.9% sodium chloride). Commencement of cardiopulmonary bypass decreased renal medullary tissue oxygenation in the placebo group (mean (95%CI) 5.96 (4.24-7.23) to 1.56 (0.84-2.09) kPa, p = 0.001), with similar hypoxic levels observed in the dexmedetomidine group (6.33 (5.33-7.07) to 1.51 (0.33-2.39) kPa, p = 0.002). While no differences in kidney function (i.e. reduced creatinine clearance) were evident, a greater incidence of histological renal tubular injury was observed in sheep receiving dexmedetomidine (7/8 sheep) compared with placebo (2/8 sheep), p = 0.041. Graded on a semi-quantitative scale (0-3), median (IQR [range]) severity of histological renal tubular injury was higher in the dexmedetomidine group compared with placebo (1.5 (1-2 [0-3]) vs. 0 (0-0.3 [0-1]) respectively, p = 0.013). There was no difference in cerebral tissue microglial activation (neuroinflammation) between the groups. Dexmedetomidine did not reduce renal medullary hypoxia or cerebral neuroinflammation in sheep undergoing cardiopulmonary bypass.