Dexmedetomidine reduces the incidence of postoperative delirium after cardiac surgery: a meta-analysis of randomized controlled trials

Perioperative dexmedetomidine for the prevention of postoperative delirium after cardiac surgery: a systematic review, Bayesian meta-analysis, and Bayesian re-analysis of the DECADE trial

BACKGROUND

Dexmedetomidine is seen as a promising agent for the prevention of postoperative delirium after cardiac surgery, but the largest study (DECADE) paradoxically suggested an increased risk of delirium.

METHODS

Studies were selected using inclusion/exclusion criteria after conducting online database searches for randomised controlled trials. The primary outcome was the incidence of postoperative delirium with a minimum clinically important difference (MCID), defined as an odds ratio >1.20 or <0.84. Publication bias was quantified using Bayesian model averaging. A random-effects meta-analysis with weakly informative priors was performed. Bayesian re-analysis of DECADE using several different priors including a prior based on this meta-analysis (excluding DECADE) was also performed.

RESULTS

We identified 12 eligible randomised controlled trials (3539 participants). The overall pooled effect showed a mean benefit from dexmedetomidine in delirium prevention (odds ratio 0.67 [95% credible interval 0.45, 0.92]), but any definitive evidence of benefit disappeared after accounting for publication bias (odds ratio 1.15 [95% credible interval 0.93, 2.51]). Bayesian re-analysis of the DECADE trial under a vague prior showed a 1.5% posterior probability of any benefit and only a 0.1% probability of an MCID for benefit. Combining DECADE with the unadjusted meta-analysis-derived prior increased the probability of an MCID for benefit to 17.8%, which decreased to 0.2% using the meta-analysis-derived prior adjusted for publication bias.

CONCLUSIONS

Pooled evidence suggests dexmedetomidine is associated with reduced incidence of postoperative delirium; however, this is highly sensitive to the possibility of publication bias. Bayesian re-analysis of the recently published DECADE trial showed the effect of dexmedetomidine differs markedly depending on the weight given to previous studies. Hence, any true benefit from the use of dexmedetomidine over standard care in this population cannot be definitively characterised at present.

SYSTEMATIC REVIEW PROTOCOL

CRD42023401623 (PROSPERO).

Impact of perioperative dexmedetomidine on postoperative delirium in adult undergoing cardiac surgery: A comprehensive bibliometrix and meta-analysis

This bibliometrix and meta-analysis aimed to evaluate the efficacy of perioperative dexmedetomidine (DEX) on postoperative delirium (POD) in adult patients undergoing cardiac surgery. A comprehensive search of electronic databases identified 21 randomized controlled trials involving 5210 patients. The primary outcome was the incidence of POD from the first day to seven days post-surgery. The meta-analysis revealed that DEX significantly reduced POD incidence compared to various controls (RR 0.70; 95 % CI 0.54-0.89; P = 0.004). Subgroup analyses showed that DEX was particularly effective when compared to propofol (RR 0.48; 95 % CI 0.30-0.78; P = 0.003). However, no significant differences were observed in the duration of anesthesia, surgery, or ICU/hospital stay. Notably, DEX was associated with a higher incidence of hypotension (RR 1.90; 95 % CI 1.16-3.10; P = 0.01). The study highlights the potential neuroprotective benefits of DEX but underscores the need for careful monitoring of hemodynamic stability. Future research should focus on optimizing DEX dosing protocols and exploring its broader impact on postoperative recovery and patient outcomes.

Efficacy of perioperative dexmedetomidine in postoperative pain and neurocognitive functions in orthopedic surgery: a systematic review and meta-analysis with trial sequential analysis of randomized controlled trials

INTRODUCTION

With an estimated 2.1 million hip and knee replacements performed annually in developed countries, orthopedic surgeries can result in complications such as postoperative pain and cognitive dysfunctions. Dexmedetomidine shows potential for reducing pain and opioid use and improving cognitive outcomes, but its efficacy in orthopedic settings needs further evaluation.

METHODS

A comprehensive literature search was performed across electronic databases (e.g., PubMed) up to 1 June 2024 to identify relevant randomized controlled trials (RCTs) investigating the use of dexmedetomidine for orthopedic surgeries. The primary outcomes included visual analog scale (VAS), opioid consumption, incidence of postoperative cognitive dysfunction (POCD), and postoperative delirium (POD). Meta-analysis was conducted using RevMan 5.3 and Stata 16.0, with statistical significance set at P < 0.05. Sensitivity analyses, along with trial sequential analysis (TSA), were used to evaluate the robustness of the findings.

RESULTS

The meta-analysis included 59 RCTs with 7713 participants and demonstrated that dexmedetomidine significantly reduced postoperative VAS score (mean difference [MD] -0.50, P = 0.0003) and opioid consumption (MD -11.91, P < 0.0001) and decreased the incidence of POCD (risk ratio [RR] 0.59, P = 0.006) and POD (RR 0.49, P < 0.0001). Dexmedetomidine also prolonged motor (MD: 1.70, P < 0.0001) and sensory block durations (MD: 1.80, P < 0.0001) and delayed the time to first rescue analgesics (MD: 1.51, P < 0.0001). TSA and sensitivity analysis confirmed the robustness and reliability of the results, whereas meta-regression revealed no significant effect of variables on primary outcomes.

CONCLUSION

Our study demonstrates that intravenous dexmedetomidine significantly improved postoperative pain and neurocognitive functions in orthopedic surgery patients.

The Prevention and Treatment of Postoperative Delirium in the Elderly: A Narrative Systematic Review of Reviews

OBJECTIVES

Postoperative delirium (POD) is a common complication after major surgeries, posing significant challenges to patient recovery and outcomes, particularly among the elderly. A narrative systematic review was conducted to assess the clinical effectiveness and safety of interventions aimed at preventing and treating POD.

METHODS

A review of the literature from 2017 to September 29, 2023, was conducted using MEDLINE, EMBASE, and CINAHL. Systematic reviews, with or without meta-analyses, as well as practice guidelines, were included. Participants were adults, ≥60 years. The methodological quality of included reviews was appraised using AMSTAR 2.

RESULTS

After the search strategy identified 2295 references, 36 review studies were selected. Multicomponent interventions, incorporating both pharmacological and nonpharmacological approaches, demonstrate promise, particularly in hip fracture patients. Notably, dexmedetomidine emerges as a potential preventive measure, showing a notable reduction in delirium incidence following cardiac surgery. While several pharmacological interventions show potential, evidence remains inconclusive, necessitating further investigation. Similarly, varying anesthesia type and monitoring methods has mixed outcomes on delirium prevention. Despite methodological variations and quality appraisal limitations, this review underscores the importance of multicomponent interventions and the potential efficacy of dexmedetomidine in mitigating POD. Integration of evidence-based protocols into clinical practice is advocated to improve patient outcomes. However, the complex interplay between intervention components calls for further research to optimize delirium management strategies.

CONCLUSIONS

The strength of evidence associated with multicomponent interventions and dexmedetomidine use should require a genuine commitment from health care institutions to support their integration into efficient strategies to prevent and treat POD. Ongoing research is vital to uncover their full potential and refine clinical protocols, ultimately enhancing patient care outcomes.

Intravenous injection of 0.5 μg/kg dexmedetomidine during plasma resection of tonsil adenoids can reduce the incidence of delirium and hemodynamics in children

OBJECTIVE

To investigate the effects of different doses of dexmedetomidine on delirium and hemodynamics after plasma resection of adenoids in children.

METHODS

A retrospective analysis was conducted on the clinical data of 80 children who underwent plasma adenoidectomy of tonsil at the Pediatric Hospital of Fudan University from January 2022 to December 2023. The patients were divided into normal saline group, 0.1 μg/kg dexmedetomidine group, and 0.5 μg/kg dexmedetomidine group according to the dose of dexmedetomidine injected intravenously. Hemodynamic changes, modified Yale Preoperative Anxiety Scale (mYPAS-SF) scores, pharyngeal pain (at rest and during swallowing), coagulation function, and postoperative adverse reactions were compared at T0, 10 min after dexmedetomidine pumping (T1), extubation (T2), recovery (T3), 2 h after returning to ward (T4), 12 h after returning to ward (T5) and 24 h after returning to ward (T6), respectively.

RESULTS

There were no significant differences in extubation time, recovery time, or unguardianship time among the three groups (P>0.05). The incidence of postoperative delirium was significantly lower in the 0.1 μg/kg dexmedetomidine group and 0.5 μg/kg dexmedetomidine group compared to the normal saline group (P<0.05), with the 0.5 μg/kg group showing better results. At T2, heart rate (HR) and mean arterial pressure (MAP) levels were significantly lower in 0.1 μg/kg group and 0.5 μg/kg dexmedetomidine group than those in normal saline group (P<0.05). The mYPAS-SF score was significantly lower in the 0.1 μg/kg group and 0.5 μg/kg dexmedetomidine groups than that of the normal saline group at T3, T4 and T5 (P<0.05). The score of pharyngeal pain during swallowing was significantly lower in the 0.5 μg/kg dexmedetomidine group at T5 than that of the normal saline group and 0.1 μg/kg dexmedetomidine group (P<0.05). Coagulation values (PT, APTT, and TT) were significantly altered 36 hours post-surgery, with PT, APTT, and TT increasing, while fibrinogen (FIB) decreased (P<0.05). Postoperative nasopharyngeal hemorrhage occurred in one case and nausea/vomiting in two cases in the saline group. No anesthesia-related adverse reactions were observed in the dexmedetomidine group.

CONCLUSION

Intravenous injection of 0.5 μg/kg dexmedetomidine during plasma resection of tonsillar adenoids can reduce the incidence of postoperative delirium, stabilize hemodynamics, relieve postoperative anxiety and pharyngeal pain, with minimal impacts on coagulation function. Additionally, it reduces the incidence of adverse reactions, making it a promising option for clinical use.

Effectiveness of perioperative remimazolam in preventing postoperative delirium: a systematic review and meta-analysis

BACKGROUND

To compare the POD rates in patients undergoing non-cardiac surgery who received remimazolam perioperatively versus placebo or other sedatives.

METHODS

We systematically searched four major databases (Cochrane Central Register of Controlled Trials, Web of Science, Embase, and PubMed) for relevant randomized controlled trials (RCTs) up to July 11, 2024. Literature quality evaluation was used the bias risk table in Review Manager 5.4. The primary outcome of interest was POD, and secondary outcomes were the hypotension risk, bradycardia and, nausea and vomiting.

RESULTS

Across 11 trials involving 1985 participants, we recorded 309 cases of POD during follow-up. In trials where the control group received saline, remimazolam decrease the risk of POD significantly by 70% (RR 0.30, 95% CI [0.19, 0.46]; p < 0.00001). Statistical analysis did not show significant difference in the risk of POD between the remimazolam group and the groups receiving either dexmedetomidine (RR 1.23 [0.64, 2.37]; p = 0.53) or propofol (RR 0.83 [0.60, 1.16]; p = 0.28). Regarding adverse events, remimazolam significantly reduces the morbidity of hypotension compared to dexmedetomidine (RR 0.25 [0.10, 0.65]; p = 0.004) and propofol (RR 0.45 [0.33, 0.60]; p < 0.00001). In addition, there were no significant differences in the incidence of bradycardia (RR 0.85; 95% CI [0.34-2.12], p = 0.72) and nausea and vomiting (RR 1.06; 95% CI [0.74-1.51], p = 0.77) between remimazolam and the control group.

CONCLUSIONS

During the perioperative period, using remimazolam can lower POD risk after surgery for patients who had non-cardiac surgery, but remimazolam does not work better than dexmedetomidine or propofol. Compared with the dexmedetomidine and propofol, remimazolam also has apparent advantages in preventing intraoperative hypotension.

Effect of perioperative dexmedetomidine on sleep quality in adult patients after noncardiac surgery: A systematic review and meta-analysis of randomized trials

BACKGROUND

Dexmedetomidine may improve sleep quality after surgery, but conflicting results also exist. Herein, we explored the effects of perioperative dexmedetomidine on postoperative sleep quality in adult patients.

METHODS

In this systematic review and meta-analysis, randomized controlled trials investigating the effects of perioperative dexmedetomidine on sleep quality after noncardiac surgery were retrieved from Cochrane Library, PubMed, and EMBASE from inception to January 12, 2023, and updated on March 15, 2024. The Cochrane Collaboration's tool was applied to assess risk of bias. A random-effects model was used for meta-analysis. The primary outcome was the subjective sleep quality score on the first night after surgery.

RESULTS

A total of 29 trials containing 5610 participants were included. The subjective sleep score on the first postoperative night was lower (better) with dexmedetomidine than with placebo (SMD [standardized mean difference] = -0.8, 95% CI -1.1 to -0.6, p<0.00001; I2 = 93%; 22 trials; n = 4611). Sensitivity analysis showed that overall conclusion was not changed (SMD = -0.8, 95% CI -1.1 to -0.5, p<0.00001; I2 = 93%; 14 trials; n = 3846). Results of polysomnographic monitoring showed improved sleep structure with dexmedetomidine on the first night after surgery, as manifested by increased sleep efficiency index and stage N2 sleep and decreased arousal index and stage N1 sleep.

CONCLUSIONS

This systematic review suggests that, among patients who underwent noncardiac surgery, perioperative dexmedetomidine administration may improve early postoperative sleep quality pattern. However, the resulting evidence were of low or very low qualities and further studies are required to confirm our results.

PROSPERO REGISTRATION NUMBER

CRD42023390972.

Retrospective comparison of the effects of remimazolam and dexmedetomidine on postoperative delirium in elderly patients undergoing orthopedic surgery of the lower extremities under spinal anesthesia

PURPOSE

Remimazolam is often used for perioperative sedation due to its rapid onset and offset. However, the possible association between remimazolam and postoperative delirium (POD) remains undetermined. The present study evaluated whether remimazolam increased the incidence of POD compared with dexmedetomidine in elderly patients undergoing orthopedic surgery of the lower extremities.

METHODS

This retrospective study included patients aged ≥ 65 years who had undergone orthopedic surgery of the lower extremities under spinal anesthesia from January 2020 to November 2022 and were sedated with continuous intravenous infusion of dexmedetomidine or remimazolam. The incidence of POD was assessed through a validated comprehensive review process of each patient's medical records. The effect of remimazolam on the occurrence of POD compared with dexmedetomidine was evaluated by propensity score weighted multivariable logistic models.

RESULTS

A total of 447 patients were included in the final analysis. The crude incidence of POD within 3 days after surgery was 7.5% (17/226) in the dexmedetomidine group and 11.8% (26/221) in the remimazolam group, increasing to 9.7% (22/226) and 15.8% (35/221), respectively (p = 0.073), within 5 days. The multivariable models showed that, compared with dexmedetomidine, intraoperative sedation with remimazolam significantly increased the occurrence of POD within 3 days (odds ratio [OR] 2.21, 95% confidence interval [CI] 1.31 to 3.82, p = 0.003) and 5 days (OR 2.10, 95% CI 1.32 to 3.40, p = 0.002).

CONCLUSION

Compared with dexmedetomidine, remimazolam infusion may be associated with a higher risk of POD in elderly patients undergoing orthopedic surgery of the lower extremities under spinal anesthesia.

Clinical investigation into risk factors for delirium post-cardiac surgery and its implications for nursing intervention guided by behavior change theory

BACKGROUND

This study explores the factors contributing to the occurrence of delirium following cardiac surgery and devises nursing strategies rooted in behavior change theory.

METHODS

A cohort of 320 cardiac surgery patients was selected, categorized into two groups: 93 cases where postoperative delirium (POD) was anticipated, and 227 cases where it was not. Preoperative, intraoperative, and postoperative factors of POD were scrutinized using single-factor analysis, while binary logistic regression analysis was employed to pinpoint risk factors.

RESULTS

Among the 320 patients, 93 displayed POD symptoms post-surgery, yielding an incidence of 29.06%. Preoperative univariate analysis disclosed significant differences in gender, age, smoking, hypertension, and diabetes (P < 0.05). Intraoperatively, significant differences were noted in the American Society of Anesthesiologists (ASA) anesthesia grade (II, III, and IV), surgery time, cardiopulmonary bypass duration, and aortic occlusion duration (P < 0.05). Post-surgery, significant differences were observed in the duration of Intensive Care Unit (ICU) stay, mechanical ventilation time, and visual analogue scale (VAS) scores (P < 0.05). Multivariate Logistic regression identified surgery time (OR = 2.334, P < 0.001), ICU admission duration (OR = 1.457, P < 0.001), mechanical ventilation time (OR = 1.235, P = 0.004), and VAS scores (OR = 2.986, P < 0.001) as independent risk factors for POD. ROC curve analysis indicated higher sensitivity and specificity in predicting POD with surgery time, ICU stay duration, mechanical ventilation time, and VAS scores.

CONCLUSION

Irrespective of the surgical intervention type, surgery time, ICU stay duration, mechanical ventilation time, and VAS scores are recognized as risk factors for POD in cardiac surgery patients. Hence, continuous patient monitoring and early intervention tailored to specific risk factors are essential in clinical practice to mitigate POD incidence.

Postoperative Delirium and the Older Adult: Untangling the Confusion

Postoperative delirium is one of the most prevalent postoperative complications, affecting mostly older adults. Its incidence is expected to rise because of surgical advances, shifting demographics, and increased life expectancy. Although an acute alteration in brain function, postoperative delirium is associated with adverse outcomes, including progressive cognitive decline and dementia, that place significant burdens on patients' lives and healthcare systems. This has prompted efforts to understand the mechanisms of postoperative delirium to provide effective prevention and treatment. There are multiple mechanisms involved in the etiology of postoperative delirium that share similarities with the physiological changes associated with the aging brain. In addition, older patients often have multiple comorbidities including increased cognitive impairment that is also implicated in the genesis of delirium. These tangled connections pinpointed a shift toward creation of a holistic model of the pathophysiology of postoperative delirium. Scientific advancements integrating clinical risk factors, possible postoperative delirium biomarkers, genetic features, digital platforms, and other biotechnical and information technological innovations, will become available in the near future. Advances in artificial intelligence, for example, will aggregate cognitive testing platforms with patient-specific postoperative delirium risk stratification studies, panels of serum and cerebrospinal fluid molecules, electroencephalogram signatures, and gut microbiome features, along with the integration of novel polygenetic variants of sleep and cognition. These advances will allow for the enrollment of high-risk patients into prevention programs and help uncover new pharmacologic targets.

Update of the European Society of Anaesthesiology and Intensive Care Medicine evidence-based and consensus-based guideline on postoperative delirium in adult patients

Postoperative delirium (POD) remains a common, dangerous and resource-consuming adverse event but is often preventable. The whole peri-operative team can play a key role in its management. This update to the 2017 ESAIC Guideline on the prevention of POD is evidence-based and consensus-based and considers the literature between 01 April 2015, and 28 February 2022. The search terms of the broad literature search were identical to those used in the first version of the guideline published in 2017. POD was defined in accordance with the DSM-5 criteria. POD had to be measured with a validated POD screening tool, at least once per day for at least 3 days starting in the recovery room or postanaesthesia care unit on the day of surgery or, at latest, on postoperative day 1. Recent literature confirmed the pathogenic role of surgery-induced inflammation, and this concept reinforces the positive role of multicomponent strategies aimed to reduce the surgical stress response. Although some putative precipitating risk factors are not modifiable (length of surgery, surgical site), others (such as depth of anaesthesia, appropriate analgesia and haemodynamic stability) are under the control of the anaesthesiologists. Multicomponent preoperative, intra-operative and postoperative preventive measures showed potential to reduce the incidence and duration of POD, confirming the pivotal role of a comprehensive and team-based approach to improve patients' clinical and functional status.

Post-cardiac Surgery Delirium: When the Details Matter!

How to cite this article: Suresh V, Magoon R. Post-cardiac Surgery Delirium: When the Details Matter! Indian J Crit Care Med 2024;28(2):185-187.

Clinical Use of Adrenergic Receptor Ligands in Acute Care Settings

In this chapter, we review how ligands, both agonists and antagonists, for the major classes of adrenoreceptors, are utilized in acute care clinical settings. Adrenergic ligands exert their effects by interacting with the three major classes of adrenoceptors. Adrenoceptor agonists and antagonists have important applications, ranging from treatment of hypotension to asthma, and have proven to be extremely useful in a variety of clinical settings of acute care from the operating room to the critical care environment. Continued research interpreting the mechanisms of adrenoreceptors may help the discovery of new drugs with more desirable clinical profiles.

The impact of a preoperative nurse-led orientation program on postoperative delirium after cardiovascular surgery: a retrospective single-center observational study

BACKGROUND

Postoperative delirium in intensive care is common and associated with mortality, cognitive impairment, prolonged hospital stays and high costs. We evaluate whether a nurse-led orientation program could reduce the incidence of delirium in the intensive care unit after cardiovascular surgery.

METHODS

In this retrospective cohort study, we enrolled patients admitted to the intensive care unit for planned cardiovascular surgery between January 2020 and December 2021. A nurse-led orientation program based on a preoperative visit was routinely introduced from January 2021. We assessed the association between these visits and postoperative delirium in the intensive care unit. We also assessed predictors of postoperative delirium with baseline and intraoperative characteristics.

RESULTS

Among 253 patients with planned cardiovascular surgery, 128 (50.6%) received preoperative visits. Valve surgery comprised 44.7%, coronary surgery 31.6%, and aortic surgery 20.9%. Cardiopulmonary bypass use and transcatheter surgery were 60.5% and 12.3%, respectively. Incidence of delirium was lower in patients that received preoperative visits, and median hospital stay was shorter than in those without visits (18 patients [14.1%] vs 34 patients [27.2%], P < 0.01; 14 days vs 17 days, P < 0.01). After adjusting predefined confounders, preoperative visits were independently associated with decreased incidence of delirium (adjusted odds ratio [aOR] 0.45; 95% confidence interval [95% CI] 0.22-0.84). Other predictors of delirium were higher European System for Cardiac Operative Risk Evaluation II score and lower minimum intraoperative cerebral oxygen saturation.

CONCLUSIONS

A preoperative nurse-led orientation program was associated with reduction of postoperative delirium and could be effective against postoperative delirium after cardiovascular surgery. Trial registration UMIN Clinical Trial Registry no. UMIN000048142. Registered 22, July, 2022, retrospectively registered, https://center6.umin.ac.jp/cgi-open-bin/ctr/ctr_view.cgi?recptno=R000054862 .

Delirium Prevention and Management in Frail Surgical Patients

Delirium, an acute, fluctuating impairment in cognition and awareness, is one of the most common causes of postoperative brain dysfunction. It is associated with increased hospital length of stay, health care costs, and mortality. There is no FDA-approved treatment of delirium, and management relies on symptomatic control. Several preventative techniques have been proposed, including the choice of anesthetic agent, preoperative testing, and intraoperative monitoring. Frailty, a state of increased vulnerability to adverse events, is an independent and potentially modifiable risk factor for the development of delirium. Diligent preoperative screening techniques and implementation of prevention strategies could help improve outcomes in high-risk patients.

Postoperative Application of Dexmedetomidine is the Optimal Strategy to Reduce the Incidence of Postoperative Delirium After Cardiac Surgery: A Network Meta-Analysis of Randomized Controlled Trials

BACKGROUND

Previous pairwise meta-analyses demonstrated the efficacy and safety of dexmedetomidine in preventing postoperative delirium (POD) after cardiac surgery; however, the optimal time of applying dexmedetomidine remains unclear.

OBJECTIVE

This network meta-analysis aimed to determine the optimal time of using dexmedetomidine to reduce the incidence of POD following cardiac surgery.

METHODS

We first retrieved eligible randomized controlled trials (RCTs) from previous meta-analyses, and then an updated search was performed to identify additional RCTs in PubMed, Embase, and the Cochrane library from January 1, 2021 to October 31, 2021. Two authors screened literature, collected data, and evaluated bias risk of eligible studies. Finally, we performed Bayesian network analysis using R version 3.6.1 with the "gemtc" and "rjags" package.

RESULTS

Eighteen studies with 2636 patients were included, and all studies were identified from previous meta-analyses. Results showed that postoperative dexmedetomidine reduced the risk of POD compared with normal saline (NS) (odds ratio [OR], 0.13; 95% credible interval [CrI], 0.03-0.35) and propofol (PRO) (OR, 0.19; 95%CrI, 0.04-0.66). Postoperative dexmedetomidine was associated with a lower incidence of POD compared with perioperative dexmedetomidine (OR, 0.21; 95% CrI, 0.04-0.82). Moreover, postoperative dexmedetomidine had the highest probability of ranking best (90.98%), followed by intraoperative dexmedetomidine (46.83%), PRO (36.94%), perioperative dexmedetomidine (30.85%), and NS (60.02%).

CONCLUSION AND RELEVANCE

Dexmedetomidine reduces the incidence of POD compared with PRO and NS in patients undergoing cardiac surgery, and postoperative application of dexmedetomidine is the optimal time.

Cardiac surgery, ICU sedation, and delirium: is dexmedetomidine the silver bullet?

PURPOSE OF REVIEW

Delirium is a marker of acute brain insufficiency and a harbinger of poor outcomes and increased healthcare costs. Despite success preventing delirium by nonpharmacologic measures, the incidence in the postcardiac surgical ICU population remains high. Dexmedetomidine, a selective alpha-2 agonist, is a plausible preventive agent with sedative, anxiolytic, analgesic, sympatholytic and anti-inflammatory properties, and is the subject of very active study in cardiac surgery populations.

RECENT FINDINGS

Recent trials, including DEXACET (2019), DECADE (2020), LOWDEXDEL (2021), and DIRECT (2022) individually, failed to show a benefit for dexmedetomidine and highlighted associated risks. Meta-analyses have offered conflicting results, highlighting the complexity of delirium, and likely interaction of multiple etiological pathways; those that concluded benefit often were driven by trials at high risk of bias. Meta-analyses excluding biased trials currently suggest no benefit for dexmedetomidine over control in unselected cardiac surgical populations.

SUMMARY

Although using dexmedetomidine to prevent delirium in unselected cardiac surgical patients is not supported by current evidence, there remains hope that it may offer benefits in highly selected populations, and further trials are ongoing.

Alpha-2-adrenergic receptor agonists for the prevention of delirium and cognitive decline after open heart surgery (ALPHA2PREVENT): protocol for a multicentre randomised controlled trial

INTRODUCTION

Postoperative delirium is common in older cardiac surgery patients and associated with negative short-term and long-term outcomes. The alpha-2-adrenergic receptor agonist dexmedetomidine shows promise as prophylaxis and treatment for delirium in intensive care units (ICU) and postoperative settings. Clonidine has similar pharmacological properties and can be administered both parenterally and orally. We aim to study whether repurposing of clonidine can represent a novel treatment option for delirium, and the possible effects of dexmedetomidine and clonidine on long-term cognitive trajectories, motor activity patterns and biomarkers of neuronal injury, and whether these effects are associated with frailty status.

METHODS AND ANALYSIS

This five-centre, double-blind randomised controlled trial will include 900 cardiac surgery patients aged 70+ years. Participants will be randomised 1:1:1 to dexmedetomidine or clonidine or placebo. The study drug will be given as a continuous intravenous infusion from the start of cardiopulmonary bypass, at a rate of 0.4 µg/kg/hour. The infusion rate will be decreased to 0.2 µg/kg/hour postoperatively and be continued until discharge from the ICU or 24 hours postoperatively, whichever happens first.Primary end point is the 7-day cumulative incidence of postoperative delirium (Diagnostic and Statistical Manual of Mental Disorders, fifth edition). Secondary end points include the composite end point of coma, delirium or death, in addition to delirium severity and motor activity patterns, levels of circulating biomarkers of neuronal injury, cognitive function and frailty status 1 and 6 months after surgery.

ETHICS AND DISSEMINATION

This trial is approved by the Regional Committee for Ethics in Medical Research in Norway (South-East Norway) and by the Norwegian Medicines Agency. Dissemination plans include publication in peer-reviewed medical journals and presentation at scientific meetings.

TRIAL REGISTRATION NUMBER

NCT05029050.

Dexmedetomidine in Prevention of Postoperative Delirium: A Systematic Review

Delirium is defined by the DSM-5 as a fluctuating course of disturbance in attention, cognition, and awareness that develops over a short period without any pre-existing neurocognitive disorder. As people age, there is an increased risk of complications that may occur following a surgical procedure and one such acute complication is delirium. Studies are emerging to reduce the incidence of postoperative delirium, and one such preventive measures implemented in recent years include the administration of dexmedetomidine, a high selectivity α-2 adrenoceptor agonist. This study aims to review the efficacy of Dexmedetomidine in the prevention of postoperative delirium in randomized controlled trials in patients older than 18 years of age. The literature was explored in three online databases, namely, PubMed, Science Direct, and Scopus. Appropriate keywords and MesH terms were employed to scrutinize relevant articles that demonstrated the effects of dexmedetomidine in the prevention of postoperative delirium. The data was restricted to randomized controlled trials and clinical trials published from 2017 to 2021 in human patients older than >18 years of age undergoing non-cardiac-related procedures. The randomized clinical trials were critically assessed with the Cochrane risk of bias tool. We proceeded to screen 428 records with the assessment of the PRISMA chart and filtered out 420 papers to obtain a total of eight studies where we identified data such as sample size, types of surgeries in which the patients were involved, the delirium assessment tool, the plan of the administration of dexmedetomidine and the outcomes evaluated in each study. The Confusion Assessment Method (CAM) was the prevailing assessment tool used with the sole purpose to evaluate the incidence of postoperative delirium as the primary outcome, and assessment of inflammatory cytokines, sleep quality, and pain scales were considered as secondary outcomes. The dosage of dexmedetomidine varied among studies, and it displayed varying impacts on postoperative delirium and the secondary outcomes as well. Limitations include varying ages and ethnicities of the population. It was concluded that dexmedetomidine prevents the development of postoperative delirium in elderly patients undergoing non-cardiac surgical interventions by modulating important predisposing factors such as neuroinflammation, pain, and sleep quality. No funding was made for this study.

Year in Review 2021: Noteworthy Literature in Cardiothoracic Critical Care

This year marked a number of milestones in critical care. As vaccines for the SARS-CoV-2 virus became widely available and were confirmed to be exceptionally effective against severe illness and hospitalization, we were then faced with new variants and the resource-intense responses necessary to combat them. Despite challenges new and old, we have persevered and continued to provide excellent care to our patients while pushing the boundaries of clinical research. This article is a collection of studies published in 2021 relevant to critical care, with a specific focus on cardiothoracic critical care. To ignore the impact of the COVID-19 pandemic would do a disservice to our colleagues, many of whom have made incredible breakthroughs in novel therapies to the coronavirus, and yet we present additional themes of delirium, acute kidney injury, lung transplant, advances in ECMO as well as biomarkers of sepsis.