The effect of dexmedetomidine and clonidine on the inflammatory response in critical illness: a systematic review of animal and human studies

Association between Dexmedetomidine Use and Mortality in Patients with COVID-19 Receiving Invasive Mechanical Ventilation: A U.S. National COVID Cohort Collaborative (N3C) Study

(1) Background/Objectives: Dexmedetomidine is a sedative for patients receiving invasive mechanical ventilation (IMV) that previous single-site studies have found to be associated with improved survival in patients with COVID-19. The reported clinical benefits include dampened inflammatory response, reduced respiratory depression, reduced agitation and delirium, improved preservation of responsiveness and arousability, and improved hypoxic pulmonary vasoconstriction and ventilation-perfusion ratio. Whether improved mortality is evident in large, multi-site COVID-19 data is understudied. (2) Methods: The association between dexmedetomidine use and mortality in patients with COVID-19 receiving IMV was assessed. This retrospective multi-center cohort study utilized patient data in the United States from health systems participating in the National COVID Cohort Collaborative (N3C) from 1 January 2020 to 3 November 2022. The primary outcome was 28-day mortality rate from the initiation of IMV. Propensity score matching adjusted for differences between the group with and without dexmedetomidine use. Adjusted hazard ratios (aHRs) for 28-day mortality were calculated using multivariable Cox proportional hazards models with dexmedetomidine use as a time-varying covariate. (3) Results: Among the 16,357,749 patients screened, 3806 patients across 17 health systems met the study criteria. Mortality was lower with dexmedetomidine use (aHR, 0.81; 95% CI, 0.73-0.90; p < 0.001). On subgroup analysis, mortality was lower with earlier dexmedetomidine use-initiated within the median of 3.5 days from the start of IMV-(aHR, 0.67; 95% CI, 0.60-0.76; p < 0.001) as well as use prior to standard, widespread use of dexamethasone for patients on respiratory support (prior to 30 July 2020) (aHR, 0.54; 95% CI, 0.42-0.69; p < 0.001). In a secondary model that was restricted to 576 patients across six health system sites with available PaO2/FiO2 data, mortality was not lower with dexmedetomidine use (aHR 0.95, 95% CI, 0.72-1.25; p = 0.73); however, on subgroup analysis, mortality was lower with dexmedetomidine use initiated earlier than the median dexmedetomidine start time after IMV (aHR, 0.72; 95% CI, 0.53-0.98; p = 0.04) and use prior to 30 July 2020 (aHR, 0.22; 95% CI, 0.06-0.78; p = 0.02). (4) Conclusions: Dexmedetomidine use was associated with reduced mortality in patients with COVID-19 receiving IMV, particularly when initiated earlier, rather than later, during the course of IMV as well as use prior to the standard, widespread usage of dexamethasone during respiratory support. These particular findings might suggest that the associated mortality benefit with dexmedetomidine use is tied to immunomodulation. However, further research including a large randomized controlled trial is warranted to evaluate the potential mortality benefit of DEX use in COVID-19 and evaluate the physiologic changes influenced by DEX that may enhance survival.

Dexmedetomidine Inhibits Hippocampal Neuronal Damage Caused by Persistent Isoflurane-Induced Hypotension in Rat Model of Chronic Cerebral Hypoperfusion

Purpose The purpose of this study was to investigate the effect of dexmedetomidine (DEX) on hypotension-induced neuronal damage in a chronic cerebral hypoperfusion (CCH) model of rats, an established model of cerebral white matter lesions (WML) in humans, which is prevalent in the elderly and closely related to cognitive decline. Methods The CCH model rats were randomly assigned to one of four groups: normotension + no DEX (NN) group (n = 6), normotension + DEX (ND) group (n = 6), hypotension + no DEX (HN) group (n = 6), or hypotension + DEX (HD) group (n = 6). Under isoflurane anesthesia, mean arterial blood pressure was maintained at or above 80 mmHg (normotension) or below 60 mmHg (hypotension) for a duration of two hours. The DEX groups received 50 μg of DEX intraperitoneally. Two weeks later, the Y-maze test and, after preparing brain slices, immunohistochemical staining were performed using antibodies against neuronal nuclei (NeuN), microtubule-associated protein 2 (MAP2), glial fibrillary acidic protein (GFAP), and Ionized calcium-binding adapter molecule 1 (Iba1). Results Behavioral observations showed no significant differences among the groups. Significant reductions of both NeuN-positive cells and the MAP2-positive area were found in the hippocampal CA1 in the HN group compared with NN and ND groups, but not in the HD group. GFAP and Iba-1-positive areas were significantly increased in the HN group, but not in the HD group. Conclusion DEX significantly ameliorated hypotension-induced neuronal damage and both astroglial and microglial activation in the CA1 region of CCH rats.

Association of dexmedetomidine and intraoperative thermal insulation with postoperative outcomes in colorectal cancer resection

OBJECTIVE

To investigate the effects of dexmedetomidine combined with intraoperative thermal insulation on postoperative cognitive function, cellular immune status and inflammatory markers in patients undergoing radical resection for colorectal cancer.

METHODS

Fifty patients who underwent radical resection of colorectal cancer in our hospital from March 2020 to September 2021 were selected and divided into observation group (26 cases with dexmedetomidine combined with intraoperative thermal insulation intervention) and control group (24 cases with conventional anesthesia management). The evaluation measures included the mini-mental state scale (MMSE) score, CD4+ T cell, CD8+ T cell ratio and CD4+/CD8+ ratio, the level of inflammatory markers (IL-6, TNF-α, CRP), and the incidence of postoperative complications.

RESULTS

The MMSE score of the observation group was significantly higher than that of the control group on the 3rd day after operation (p < 0.001). After treatment, the proportion of CD4+ T cells, the proportion of CD8+ T cells and the ratio of CD4+/CD8+ in observation group were higher than those in control group (p < 0.01), while the inflammatory markers IL-6, TNF-α and CRP were lower than those in control group (p < 0.01). The incidence of postoperative cognitive dysfunction (POCD) in the observation group (7.69%) was significantly lower than that in the control group (33.33%) (p = 0.010), and the postoperative infection rate was also significantly decreased (p = 0.042).

CONCLUSION

Dexmedetomidine combined with intraoperative insulation can significantly improve postoperative cognitive function, maintain immune balance, reduce inflammatory response, and reduce the incidence of POCD and other postoperative complications in patients with radical resection of colorectal cancer.

Intranasal dexmedetomidine improves postoperative sleep quality in older patients with chronic insomnia: a randomized double-blind controlled trial

Objective: This study was determined to investigate the impact of intranasal dexmedetomidine (DEX) on postoperative sleep quality in older patients (age over 65) with chronic insomnia during their hospitalization after surgery. Design: A randomized double-blind controlled trial was conducted to compare the effects of intranasal dexmedetomidine spray with a placebo group. Setting and Participants: The study was carried out at Xiangya Hospital, Central South University. 110 participants with chronic insomnia were analyzed. Methods: This trial enrolled older patients who underwent total hip/knee arthroplasty and randomized them to receive intranasal dexmedetomidine (2.0 μg/kg) or saline daily at around 9 p.m. after surgery until discharge. The primary outcomes were subjective sleep quality assessed with the Leeds Sleep Evaluation Questionnaire (LSEQ). The secondary outcomes included the objective sleep quality measured with the Acti-graph, the Pittsburgh Sleep Quality Index (PSQI), the Insomnia Severity Index (ISI). The other outcomes included the incidence of delirium, levels of inflammatory factors, visual analog scale (VAS) pain scores, postoperative opioid consumption, and treatment-related adverse events. Results: 174 patients were screened for eligibility, and 110 were recruited and analyzed. The DEX group had significantly higher scores on both the LSEQ-Getting to sleep and LSEQ-Quality of Sleep at each time point compared to the placebo (p < 0.0001), The least squares (LS) mean difference in LSEQ-GTS score at T0 between placebo group and DEX group was 2 (95% CI, -1-6), p = 0.4071 and at T5 was -14 (95% CI, -17 to -10), p < 0.0001; The LS mean difference in the LSEQ-QOS score at T0 was -1 (95% CI, -4 to 1), p = 0.4821 and at T5 was -16 (95% CI, -21 to -10), p < 0.0001. The DEX group exhibited significant improvement in Total Sleep Time (TST), Sleep Onset Latency (SOL), and Sleep Efficiency (SE), at each time point after treatment compared to the placebo group (p < 0.0001). The PSQI and ISI scores in the DEX group were reduced after treatment (p < 0.001). No significant adverse events were reported with the use of dexmedetomidine. Conclusion and Implications: This study demonstrates that intranasal administration of dexmedetomidine improves postoperative sleep quality in older patients with chronic insomnia who undergo surgery, without increasing the incidence of adverse effects. Clinical Trial Registration: http://www.chictr.org.cn/, identifier ChiCTR2200057133.

Hemodynamic Safety and Effect of Dexmedetomidine on Superficial Cervical Block Quality for Carotid Endarterectomy: A Prospective Study

OBJECTIVE

Dexmedetomidine as an adjuvant to local anesthetics (LAs) in regional anesthesia has demonstrated a positive effect on the quality of regional blocks, but there are no studies on usage in superficial cervical block (SCB) for carotid endarterectomy (CEA), in which the management of mean arterial pressure is essential. The authors designed a prospective, randomized, double-blinded study to investigate the effects of the addition of dexmedetomidine on the hemodynamic management and quality of SCB.

DESIGN

A prospective, randomized, double-blinded study.

SETTING

A single-center study at a university hospital center.

PARTICIPANTS

Ultrasound-guided SCB was performed on 60 patients classified as American Society of Anesthesiologists Grades II and III undergoing elective CEA surgery who were assigned into 2 groups randomly.

INTERVENTION(S)

Both groups received 2 mg/kg of 0.5% levobupivacaine with 2 mg/kg of 2% lidocaine. The intervention group additionally received 50 μg of dexmedetomidine.

MEASUREMENTS AND MAIN RESULTS

The onset and duration of sensory block and analgesia, hemodynamic parameters, and adverse effects were recorded. There were minimum effects on hemodynamic parameters and no differences in the incidence of adverse effects. The time to first analgesia was longer in the intervention group than in the control group (N = 30). There was no difference in the duration of the sensory block between groups. The log-rank test indicated a significant difference in the probability of the Numeric Pain Rating Scale <3.

CONCLUSION

The addition of 50 μg of dexmedetomidine to 0.5% levobupivacaine and 2% lidocaine for SCB did not influence the hemodynamics and frequency of adverse effects. The median sensory block duration time showed no statistical difference between the groups, but the quality of analgesia postoperatively was much improved in the study group.

Alfaxalone provides reliable sedation for intradermal allergen testing in dogs and does not significantly affect results when compared to dexmedetomidine

BACKGROUND

Dexmedetomidine (Dexmedetomidine hydrochloride-Dexdomitor; Zoetis) is the preferred sedative used for canine intradermal allergen testing (IDT) in the United States. Alfaxalone (Alfaxan Multidose; Jurox Animal Health) is a neuroactive steroid, and its effect on sedation and allergen reactivity scores is unknown.

HYPOTHESIS/OBJECTIVES

We hypothesised that alfaxalone would produce an adequate level of sedation with fewer cardiovascular adverse effects and would not affect allergen reactivity scores or histamine wheal size compared to dexmedetomidine.

MATERIALS AND METHODS

Twenty client-owned dogs were included in two groups: 10 atopic and 10 nonatopic. In a randomised, controlled, blinded, cross-over design all dogs underwent two modified IDT, 1-4 weeks apart, using intravenous dexmedetomidine (2.87-5.22 μg/kg) or alfaxalone (1.8-2.4 mg/kg). Anaesthetic parameters and sedation level were recorded over 25 min using a validated canine sedation scale described by Grint et al. (Small Anim Pract, 2009, 50, 62). Simultaneously, both objective and subjective reactivity scores were measured in technical triplicates at 10, 15 and 20 min. The modified IDT included eight allergens, histamine-positive and saline-negative controls.

RESULTS

Alfaxalone produced a significantly higher sedation score across all time points (p < 0.05). All objective scores were significantly correlated to the corresponding subjective scores (Spearman R = 0.859, p < 0.0001). Sedative used did not significantly affect subjective allergen scores for nine atopic dogs (p > 0.05, 15 min). Sedative used did not affect the diameter of objective scores for individual allergens and histamine wheals (p > 0.05, 15 min).

CONCLUSIONS AND CLINICAL RELEVANCE

Intravascular alfaxalone is an alternative sedative for IDT in dogs. Alfaxalone may be preferred to dexmedetomidine in some clinical scenarios as a result of having fewer cardiovascular adverse effects.

Dexmedetomidine improves the outcomes for pediatric severe sepsis with mechanical ventilation

BACKGROUND

The sedative dexmedetomidine has been shown to reduce mortality in adult patients with severe sepsis, but it is not known whether children benefit. This study explored the effects of dexmedetomidine on the outcomes of children with severe sepsis with mechanical ventilation.

METHODS

In this retrospective cohort study, children with severe sepsis requiring mechanical ventilation from 2016 to 2020 were categorized as dexmedetomidine and non-dexmedetomidine group. The propensity score matching was performed to match cases in both groups. The primary outcome was 28-day mortality, and the secondary outcomes were acute kidney injury, ventilator-free days, lengths of PICU and hospital stays. The Kaplan-Meier method and was the log-rank test used to estimate the 28-day mortality rate and assess between-group differences.

RESULTS

In total, 250 patients were eligible patients: 138 in the dexmedetomidine group and 112 in the non-dexmedetomidine group. After 1:1 propensity score matching, 61 children in each group. dexmedetomidine group showed more lower 28-day mortality (9.84% vs. 26.23%, P = 0.008). During the 7-day observation period after PICU admission, the dexmedetomidine group showed significantly lower neurological and renal sub-scores at day 7 and serum creatinine level at day 3 and day 7. There were no statistical differences in the incidence of acute kidney injury, ventilator-free days, lengths of PICU and hospital stays between the two groups.

CONCLUSIONS

dexmedetomidine treatment in children with severe sepsis is associated with better outcomes and should therefore be considered for the sedation strategy.

Automated phenotyping of postoperative delirium-like behaviour in mice reveals the therapeutic efficacy of dexmedetomidine

Postoperative delirium (POD) is a complicated and harmful clinical syndrome. Traditional behaviour analysis mostly focuses on static parameters. However, animal behaviour is a bottom-up and hierarchical organizational structure composed of time-varying posture dynamics. Spontaneous and task-driven behaviours are used to conduct comprehensive profiling of behavioural data of various aspects of model animals. A machine-learning based method is used to assess the effect of dexmedetomidine. Fourteen statistically different spontaneous behaviours are used to distinguish the non-POD group from the POD group. In the task-driven behaviour, the non-POD group has greater deep versus shallow investigation preference, with no significant preference in the POD group. Hyperactive and hypoactive subtypes can be distinguished through pose evaluation. Dexmedetomidine at a dose of 25 μg kg-1 reduces the severity and incidence of POD. Here we propose a multi-scaled clustering analysis framework that includes pose, behaviour and action sequence evaluation. This may represent the hierarchical dynamics of delirium-like behaviours.

Effect of the Lipoxin Receptor Agonist BML-111 on Cigarette Smoke Extract-Induced Macrophage Polarization and Inflammation in RAW264.7 Cells

Background

Macrophages are known to play a crucial role in the chronic inflammation associated with Chronic Obstructive Pulmonary Disease (COPD). BML-111, acting as a lipoxin A4 (LXA4) receptor agonist, has shown to be effective in protecting against COPD. However, the precise mechanism by which BML-111 exerts its protective effect remains unclear.

Methods

In order to establish a cell model of inflammation, cigarette smoke extract (CSE) was used on the RAW264.7 cell line. Afterwards, an Enzyme-linked immunosorbent assay (ELISA) kit was employed to measure concentrations of tumor necrosis factor-α (TNF-α), interleukin-1beta (IL-1β), interleukin-18 (IL-18), and interleukin-10 (IL-10) in the cell supernatants of the RAW264.7 cells.In this study, we examined the markers of macrophage polarization using two methods: quantitative real-time polymerase chain reaction (qRT-PCR) and Western blot analysis. Additionally, we detected the expression of Notch-1 and Hes-1 through Western blotting.

Results

BML-111 effectively suppressed the expression of pro-inflammatory cytokines TNF-α, IL-1β, and IL-18, as well as inflammasome factors NLRP3 and Caspase-1, while simultaneously up-regulating the expression of the anti-inflammatory cytokine IL-10 induced by CSE. Moreover, BML-111 reduced the expression of iNOS, which is associated with M1 macrophage polarization, and increased the expression of Arg-1, which is associated with M2 phenotype. Additionally, BML-111 downregulated the expression of Hes-1 and the ratio of activated Notch-1 to Notch-1 induced by CSE. The effect of BML-111 on inflammation and macrophage polarization was reversed upon administration of the Notch-1 signaling pathway agonist Jagged1.

Conclusion

BML-111 has the potential to suppress inflammation and modulate M1/M2 macrophage polarization in RAW264.7 cells. The underlying mechanism may involve the Notch-1 signaling pathway.

Dexmedetomidine alleviates osteoarthritis inflammation and pain through the CB2 pathway in rats

As a common joint disease, osteoarthritis (OA) is often associated with chronic pain. Synovial inflammation is correlated with OA progression and pain. Synovial inflammation can produce a series of destructive substances, such as inflammatory factors and pain mediators, which aggravate cartilage injury and further accelerate the progression of OA. Although many studies investigated the effects of synovial inflammation on the onset and progression of OA, there are limited reports regarding slowing the progression of OA and relieving pain by modulating synovial inflammation. Therefore, there is an urgent need to search for safe and effective drugs to alleviate synovial inflammation. Dexmedetomidine, a selective α₂ agonist, has been shown to have anti-inflammatory and analgesic effects. However, its role and mechanism in OA remain unclear. Here, the effects and mechanisms of dexmedetomidine in OA synovial inflammation were investigated both in vivo and in vitro. We observed that dexmedetomidine stunted LPS-induced migration and invasion of FLSs and the expression of inflammatory factors by upregulating cannabinoid receptor type 2 (CB₂) expression. Surprisingly, the application of AM630 (CB₂ antagonist) reversed this therapeutic effect. The results of the animal experiments showed that dexmedetomidine reduced synovial inflammation and increased the pain threshold in an OA rat model. These preliminary results imply that dexmedetomidine may be an effective compound for OA treatment.

Effect of Dexmedetomidine on Postoperative Renal Function in Patients Undergoing Cardiac Valve Surgery Under Cardiopulmonary Bypass: A Randomized Clinical Trial

OBJECTIVE

The effect of dexmedetomidine on postoperative renal function was investigated in patients undergoing cardiac valve surgery under cardiopulmonary bypass (CPB).

DESIGN

A randomized controlled trial.

SETTING

University teaching, grade A tertiary hospital.

PARTICIPANTS

A total of 70 patients scheduled to undergo cardiac valve replacement or valvuloplasty under CPB were eligible and randomly divided into groups D (n = 35) and C (n = 35) between January 2020 and March 2021.

INTERVENTIONS

Patients in group D were administered 0.6 μg/kg/h of dexmedetomidine intravenously from 10 minutes before anesthesia induction to 6 hours after surgery; normal saline was used instead of dexmedetomidine in group C.

MEASUREMENTS AND MAIN RESULTS

The primary outcome was the incidence of acute kidney injury (AKI). Acute kidney injury was defined according to the Kidney Disease Improving Global Outcomes (2012). It was 22.86% and 48.57% in groups D and C, respectively (p = 0.025). The secondary outcomes were intraoperative hemodynamics and various indices in serum. Ten minutes before CPB (T₁), 10 minutes after CPB (T₂), and 30 minutes after CPB (T₃), mean arterial pressure in group D was lower than that in group C, with statistical significance (74.94 ± 8.52 v 81.89 ± 13.66 mmHg, p=0.013; 62.83 ± 11.27 v 71.86 ± 7.89 mmHg, p < 0.001; 72.26 ± 8.75 v 78.57 ± 8.83 mmHg, p = 0.004). At T₁, the heart rate in group D was significantly lower than in group C (80.89 ± 14.04 v 95.54 ± 12.53 bpm, p=0.022). The tumor necrosis factor α, interleukin-6, C-reactive protein, and cystatin C levels in group D were lower than those in group C after the surgery (T₄) and 24 hours after surgery (T₅), with statistical significance. The duration of mechanical ventilation, intensive-care-unit stay time, and hospital stay time in group D were significantly shorter than in group C. The incidences of tachycardia, hypertension, nausea, and vomiting in group D were similar to those in group C.

CONCLUSIONS

Dexmedetomidine may be considered as a way to reduce the incidence and severity of postoperative AKI in patients undergoing cardiac valve surgery under cardiopulmonary bypass.

Dexmedetomidine in Psychiatry: Repurposing of its Fast-Acting Anxiolytic, Analgesic and Sleep Modulating Properties

Drug repurposing is a strategy to identify new indications for already approved drugs. A recent successful example in psychiatry is ketamine, an anesthetic drug developed in the 1960s, now approved and clinically used as a fast-acting antidepressant. Here, we describe the potential of dexmedetomidine as a psychopharmacological repurposing candidate. This α₂-adrenoceptor agonist is approved in the US and Europe for procedural sedation in intensive care. It has shown fast-acting inhibitory effects on perioperative stress-related pathologies, including psychomotor agitation, hyperalgesia, and neuroinflammatory overdrive, proving potentially useful in clinical psychiatry. We offer an overview of the pharmacological profile and effects of dexmedetomidine with potential utility for the treatment of neuropsychiatric symptoms. Dexmedetomidine exerts fast-acting and robust sedation, anxiolytic, analgesic, sleep-modulating, and anti-inflammatory effects. Moreover, the drug prevents postoperative agitation and delirium, possibly via neuroprotective mechanisms. While evidence in animals and humans supports these properties, larger controlled trials in clinical samples are generally scarce, and systematic studies with psychiatric patients do not exist. In conclusion, dexmedetomidine is a promising candidate for an experimental treatment targeting stress-related pathologies common in neuropsychiatric disorders such as depression, anxiety disorders, and posttraumatic stress disorder. First small proof-of-concept studies and then larger controlled clinical trials are warranted in psychiatric populations to test the feasibility and efficacy of dexmedetomidine in these conditions.

Paediatric sepsis-associated encephalopathy (SAE): a comprehensive review

Sepsis-associated encephalopathy (SAE) is one of the most common types of organ dysfunction without overt central nervous system (CNS) infection. It is associated with higher mortality, low quality of life, and long-term neurological sequelae, its mortality in patients diagnosed with sepsis, progressing to SAE, is 9% to 76%. The pathophysiology of SAE is still unknown, but its mechanisms are well elaborated, including oxidative stress, increased cytokines and proinflammatory factors levels, disturbances in the cerebral circulation, changes in blood-brain barrier permeability, injury to the brain's vascular endothelium, altered levels of neurotransmitters, changes in amino acid levels, dysfunction of cerebral microvascular cells, mitochondria dysfunction, activation of microglia and astrocytes, and neuronal death. The diagnosis of SAE involves excluding direct CNS infection or other types of encephalopathies, which might hinder its early detection and appropriate implementation of management protocols, especially in paediatric patients where only a few cases have been reported in the literature. The most commonly applied diagnostic tools include electroencephalography, neurological imaging, and biomarker detection. SAE treatment mainly focuses on managing underlying conditions and using antibiotics and supportive therapy. In contrast, sedative medication is used judiciously to treat those showing features such as agitation. The most widely used medication is dexmedetomidine which is neuroprotective by inhibiting neuronal apoptosis and reducing a sepsis-associated inflammatory response, resulting in improved short-term mortality and shorter time on a ventilator. Other agents, such as dexamethasone, melatonin, and magnesium, are also being explored in vivo and ex vivo with encouraging results. Managing modifiable factors associated with SAE is crucial in improving generalised neurological outcomes. From those mentioned above, there are still only a few experimentation models of paediatric SAE and its treatment strategies. Extrapolation of adult SAE models is challenging because of the evolving brain and technical complexity of the model being investigated. Here, we reviewed the current understanding of paediatric SAE, its pathophysiological mechanisms, diagnostic methods, therapeutic interventions, and potential emerging neuroprotective agents.

The impact of stress and anesthesia on animal models of infectious disease

Stress and general anesthesia have an impact on the functional response of the organism due to the detrimental effects on cardiovascular, immunological, and metabolic function, which could limit the organism's response to an infectious event. Animal studies have formed an essential step in understanding and mitigating infectious diseases, as the complexities of physiology and immunity cannot yet be replicated in vivo. Using animals in research continues to come under increasing societal scrutiny, and it is therefore crucial that the welfare of animals used in disease research is optimized to meet both societal expectations and improve scientific outcomes. Everyday management and procedures in animal studies are known to cause stress, which can not only cause poorer welfare outcomes, but also introduces variables in disease studies. Whilst general anesthesia is necessary at times to reduce stress and enhance animal welfare in disease research, evidence of physiological and immunological disruption caused by general anesthesia is increasing. To better understand and quantify the effects of stress and anesthesia on disease study and welfare outcomes, utilizing the most appropriate animal monitoring strategies is imperative. This article aims to analyze recent scientific evidence about the impact of stress and anesthesia as uncontrolled variables, as well as reviewing monitoring strategies and technologies in animal models during infectious diseases.

Dexmedetomidine ameliorates liver injury and maintains liver function in patients with hepatocellular carcinoma after hepatectomy: a retrospective cohort study with propensity score matching

Background

Although dexmedetomidine (DEX) is widely used during the perioperative period in patients with hepatocellular carcinoma (HCC), its clinical effects on liver function and postoperative inflammation are unclear. This study aimed to explore effects of DEX on postoperative liver function and inflammation in patients with HCC after hepatectomy.

Methods

A retrospective cohort study with propensity score matching was performed. A total of 494 patients who underwent hepatectomy from June 2019 to July 2020 and fulfilled the eligibility criteria were included in this study. Baseline data, liver function indexes and inflammation-related biomarkers were collected and compared between the two groups. Survival analysis was conducted to investigate the effects of DEX on the overall survival (OS) of patients. Propensity score matching (PSM) was used to minimize bias between the two groups.

Results

The study cohort comprised 189 patients in the DEX-free group and 305 patients in the DEX group. Patients in the DEX group had lower levels of alanine transaminase (ALT, P = 0.018) and lactate dehydrogenase (LDH, P = 0.046) and higher level of serum albumin (ALB, P < 0.001) than patients in the DEX-free group before discharge. A total of 107 pairs of patients were successfully matched by PSM. Results consistently suggested that ALT and LDH levels were significantly lower (P = 0.044 and P = 0.046, respectively) and ALB levels were significantly higher (P = 0.002) in the DEX group than in the DEX-free group in the early postoperative period. No significant differences of inflammation-related biomarkers were observed between two groups after PSM. Neither the Kaplan-Meier survival analysis nor the multiple Cox regression survival analysis identified DEX as a contributing factor that would affect the OS of patients after PSM.

Conclusion

DEX exerts protective effects on liver function while has little effects on inflammation-related biomarkers in the early postoperative period in patients undergoing hepatectomy due to HCC.

Circulating oxylipin and bile acid profiles of dexmedetomidine, propofol, sevoflurane, and S-ketamine: a randomised controlled trial using tandem mass spectrometry

Background

This exploratory study aimed to investigate whether dexmedetomidine, propofol, sevoflurane, and S-ketamine affect oxylipins and bile acids, which are functionally diverse molecules with possible connections to cellular bioenergetics, immune modulation, and organ protection.

Methods

In this randomised, open-label, controlled, parallel group, Phase IV clinical drug trial, healthy male subjects (n=160) received equipotent doses (EC50 for verbal command) of dexmedetomidine (1.5 ng ml-1; n=40), propofol (1.7 μg ml-1; n=40), sevoflurane (0.9% end-tidal; n=40), S-ketamine (0.75 μg ml-1; n=20), or placebo (n=20). Blood samples for tandem mass spectrometry were obtained at baseline, after study drug administration at 60 and 130 min from baseline; 40 metabolites were analysed.

Results

Statistically significant changes vs placebo were observed in 62.5%, 12.5%, 5.0%, and 2.5% of analytes in dexmedetomidine, propofol, sevoflurane, and S-ketamine groups, respectively. Data are presented as standard deviation score, 95% confidence interval, and P-value. Dexmedetomidine induced wide-ranging decreases in oxylipins and bile acids. Amongst others, 9,10-dihydroxyoctadecenoic acid (DiHOME) -1.19 (-1.6; -0.78), P<0.001 and 12,13-DiHOME -1.22 (-1.66; -0.77), P<0.001 were affected. Propofol elevated 9,10-DiHOME 2.29 (1.62; 2.96), P<0.001 and 12,13-DiHOME 2.13 (1.42; 2.84), P<0.001. Analytes were mostly unaffected by S-ketamine. Sevoflurane decreased tauroursodeoxycholic acid (TUDCA) -2.7 (-3.84; -1.55), P=0.015.

Conclusions

Dexmedetomidine-induced oxylipin alterations may be connected to pathways associated with organ protection. In contrast to dexmedetomidine, propofol emulsion elevated DiHOMEs, oxylipins associated with acute respiratory distress syndrome, and mitochondrial dysfunction in high concentrations. Further research is needed to establish the behaviour of DIHOMEs during prolonged propofol/dexmedetomidine infusions and to verify the sevoflurane-induced reduction in TUDCA, a suggested neuroprotective agent.

Clinical trial registration

NCT02624401.

Standard opioid-containing versus opioid-sparing anesthesia on early postoperative recovery after video-assisted thoracic surgery: A propensity-weighted analysis

PURPOSE

Opioids have several adverse effects. At present, there are no large clinical studies on the effects of opioid-sparing anesthesia on early postoperative recovery after thoracoscopic surgery. This study was to investigate the effects of opioid-sparing anesthesia on early postoperative recovery after thoracoscopic surgery.

METHODS

Adult patients who underwent video-assisted thoracic surgery from 1 January 2019 to 28 February 2021 were enrolled by reviewing the electronic medical records. Participants were divided into opioid-sparing anesthesia (OSA group) and opioid-containing anesthesia (STD group) based on intraoperative opioid usage. The propensity-score analysis was to compare the early postoperative recovery of two groups. The outcome measurements included the incidence of postoperative nausea and vomiting (PONV) during an entire hospital stay, need for rescue antiemetic medication, postoperative-pain episodes within 48 h after surgery, need for rescue analgesia 48 h postoperatively, duration of postoperative hospital stay, length of PACU stay, postoperative fever, postoperative shivering, postoperative atrial fibrillation, postoperative pulmonary infection, postoperative hypoalbuminemia, postoperative hypoxemia, intraoperative blood loss, and intraoperative urine output.

RESULTS

A total of 1,975 patients were identified. No significant difference was observed in patient characteristics between the OSA and STD groups after adjusting for propensity score-based inverse probability treatment weighting. The incidence of postoperative nausea and vomiting was significantly lower in the OSA group than in the STD group (14.7% vs. 18.9%, p = 0.041). The rescue antiemetic use rate was lower in the OSA group than in the STD group (7.5% vs.12.2%; p = 0.002). PACU duration was longer in the OSA group than in the STD group (70.8 ± 29.0 min vs. 67.3 ± 22.7 min; p = 0.016). The incidence of postoperative fever was higher in the STD group than that in the OSA group (11.0% vs.7.7%; p = 0.032). There were no differences between the groups in terms of other outcomes.

CONCLUSIONS

Our results suggest that opioid-sparing anesthesia has a lower incidence of postoperative complications than opioid-based anesthetic techniques.

Use of dexmedetomidine in patients with sepsis: a systematic review and meta-analysis of randomized-controlled trials

Background

Dexmedetomidine is widely used in patients with sepsis. However, its effect on septic patients remains controversial. The objective of this study was to summarize all randomized controlled trials (RCTs) examining dexmedetomidine use in sepsis patients.

Methods

This systematic review and meta-analysis included RCTs comparing dexmedetomidine with other sedatives in adult sepsis patients. We generated pooled relative risks (RRs) and standardized mean differences and performed trial sequential analysis and a cumulative meta-analysis. The primary outcome was mortality, and the secondary outcomes were the length of the intensive care unit stay, duration of mechanical ventilation, number of ventilation-free days, incidence of total adverse event, incidence of delirium, and levels of interleukin 6, tumor necrosis factor alpha, and alanine aminotransferase.

Results

We included 19 RCTs that enrolled 1929 patients. Compared with other sedatives, dexmedetomidine decreased the all-cause mortality (RR 0.83; 95% confidence interval [CI] [0.69, 0.99]) and inflammatory response (interleukin 6 and tumor necrosis factor alpha levels at 24 h: standardized mean difference (SMD) − 2.15; 95% CI [− 3.25, − 1.05] and SMD − 1.07, 95% CI [− 1.92, − 0.22], respectively). Trial sequential analysis showed that it is not up to required information size. The overall risk adverse events was similar between dexmedetomidine and the other sedatives (RR 1.27, 95% CI [0.69, 2.36]), but dexmedetomidine increased the risk of arrhythmias (RR 1.43, 95% CI [0.59, 3.51]). Length of intensive care unit stay (SMD − 0.22; 95% CI [− 0.85, − 0.41]), duration of mechanical ventilation (SMD 0.12; 95% CI [− 1.10, 1.35]), incidence of delirium (RR 0.98; 95% CI [0.72, 1.33]), and levels of alanine aminotransferase and creatinine at 24 h were not significantly reduced.

Conclusions

Dexmedetomidine in sepsis patients could significantly reduce mortality compared with benzodiazepines but not with propofol. In addition, dexmedetomidine can significantly decrease inflammatory response in patients with sepsis compared with other sedatives. Dexmedetomidine might lead to an increased incidence of arrhythmias, but its safety profile did not show significant differences in the incidence of total adverse events. Future RCTs are needed to determine the sepsis patient population that would benefit most from dexmedetomidine and its optimal dosing regimen.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13613-022-01052-2.

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.

Effects of Dexmedetomidine on Immune Cells: A Narrative Review

As we all know, dexmedetomidine (DEX), as a highly selective α₂ adrenergic receptor agonist, exerts sedative, anti-anxiety and hypnotic effects by inhibiting the discharge of norepinephrine neurons in locus coeruleus and GABA-related hypnotic pathways. However, the role of DEX in anti-inflammatory and immune regulation has gradually attracted the attention of researchers in recent years. The α₂ adrenergic receptor is one of the members of the adrenergic receptor family, which is widely present in a variety of immune cells and mediates the biological behavior of the inflammatory immune system. At present, there have been more and more studies on the effects of DEX on immune cells and inflammatory responses, but few studies have systematically explored the anti-inflammatory and immunomodulatory effects of DEX. Here, we comprehensively review the published human and animal studies related to DEX, summarize the effects of DEX on immune cells and its role in related diseases, and propose potential research direction.

The Association of an Alpha-2 Adrenergic Receptor Agonist and Mortality in Patients With COVID-19

There is a need for treatments to reduce coronavirus disease 2019 (COVID-19) mortality. Alpha-2 adrenergic receptor (α₂ AR) agonists can dampen immune cell and inflammatory responses as well as improve oxygenation through physiologic respiratory parameters. Therefore, α₂ AR agonists may be effective in reducing mortality related to hyperinflammation and acute respiratory failure in COVID-19. Dexmedetomidine (DEX) is an α₂ AR agonist used for sedation. We performed a retrospective analysis of adults at Rush University System for Health hospitals between March 1, 2020 and July 30, 2020 with COVID-19 requiring invasive mechanical ventilation and sedation (n = 214). We evaluated the association of DEX use and 28-day mortality from time of intubation. Overall, 28-day mortality in the cohort receiving DEX was 27.0% as compared to 64.5% in the cohort that did not receive DEX (relative risk reduction 58.2%; 95% CI 42.4–69.6). Use of DEX was associated with reduced 28-day mortality on multivariable Cox regression analysis (aHR 0.19; 95% CI 0.10–0.33; p < 0.001). Adjusting for time-varying exposure to DEX also demonstrated that DEX was associated with reduced 28-day mortality (aHR 0.51; 95% CI 0.28–0.95; p = 0.03). Earlier DEX use, initiated <3.4 days from intubation, was associated with reduced 28-day mortality (aHR 0.25; 95% CI 0.13–0.50; p < 0.001) while later DEX use was not (aHR 0.64; 95% CI 0.27–1.50; p = 0.30). These results suggest an α₂ AR agonist might reduce mortality in patients with COVID-19. Randomized controlled trials are needed to confirm this observation.

Application of Dexmedetomidine combined with Propofol Intravenous Anesthesia in Laparoscopic Day Surgery in Pediatric Urology

Objectives

To evaluate the sedative and analgesic effects of dexmedetomidine combined with propofol intravenous anesthesia in laparoscopic day surgery in pediatric urology.

Methods

Eighty male children with cryptorchidism and hydrocele who underwent laparoscopic daytime surgery in our hospital from January 2019 to January 2021 were selected and randomly divided into two groups: the experimental group and the control group. Children in the experimental group ranged in age from 5.7 to 11.3, with an average of 8.52±2.17 years old, while those in the control group ranged in age from 5.3 to 12.0, with an average of 8.60±2.07 years old. There were 12 cases of cryptorchidism and 28 cases of hydrocele in the experimental group, and 14 cases of cryptorchidism and 26 cases of hydrocele in the control group. Children in the control group received conventional propofol intravenous combined anesthesia, while those in the experimental group were given dexmedetomidine (2-5 ug/kg) intranasally on the basis of conventional propofol intravenous anesthesia. The anesthetic effect, analgesic effect, serum levels of inflammatory cytokines before and after surgery and adverse drug reactions in the two groups were compared and analyzed.

Results

The awakening time, extubation time and retention time in the resuscitation room of the experimental group were shorter than those of the control group, with a statistically significant difference (P<0.05); The VAS pain scores of the experimental group were significantly lower than those of the control group at 15minutes, 12hour and 24hour after awakening, with a statistically significant difference (P<0.05). In addition, the levels of TNF-a, CRP, IL-6 and other inflammatory factors in the control group were significantly higher compared with those in the experimental group 24h after surgery, with a statistical significance (TNF-a, P=0.02; CRP, P=0.00; IL-6, P=0.03); The incidence of adverse drug reactions in the experimental group was 17.5%, while that in the control group was 12.5%, which was not statistically significant (P=0.53).

Conclusion

Dexmedetomidine combined with intravenous propofol anesthesia may be helpful to shorten the extubation time, the recovery time and the stay time in the anesthesia resuscative room, improve the analgesic effect, and may reduce the inflammatory response and the expression of serum inflammatory cytokines, with no significant increase in side effects.

Recent Advances in the Clinical Value and Potential of Dexmedetomidine

Dexmedetomidine, a highly selective α2-adrenoceptor agonist, has sedative, anxiolytic, analgesic, sympatholytic, and opioid-sparing properties and induces a unique sedative response which shows an easy transition from sleep to wakefulness, thus allowing a patient to be cooperative and communicative when stimulated. Recent studies indicate several emerging clinical applications via different routes. We review recent data on dexmedetomidine studies, particularly exploring the varying routes of administration, experimental implications, clinical effects, and comparative advantages over other drugs. A search was conducted on the PubMed and Web of Science libraries for recent studies using different combinations of the words “dexmedetomidine”, “route of administration”, and pharmacological effect. The current routes, pharmacological effects, and application categories of dexmedetomidine are presented. It functions by stimulating pre- and post-synaptic α2-adrenoreceptors within the central nervous system, leading to hyperpolarization of noradrenergic neurons, induction of an inhibitory feedback loop, and reduction of norepinephrine secretion, causing a sympatholytic effect, in addition to its anti-inflammation, sleep induction, bowel recovery, and sore throat reduction effects. Compared with similar α2-adrenoceptor agonists, dexmedetomidine has both pharmacodynamics advantage of a significantly greater α2:α1-adrenoceptor affinity ratio and a pharmacokinetic advantage of having a significantly shorter elimination half-life. In its clinical application, dexmedetomidine has been reported to present a significant number of benefits including safe sedation for various surgical interventions, improvement of intraoperative and postoperative analgesia, sedation for compromised airways without respiratory depression, nephroprotection and stability of hypotensive hemodynamics, reduction of postoperative nausea and vomiting and postoperative shivering incidence, and decrease of intraoperative blood loss. Although the clinical application of dexmedetomidine is promising, it is still limited and further research is required to enhance understanding of its pharmacological properties, patient selection, dosage, and adverse effects.

The Effect of Dexmedetomidine as a Sedative Agent for Mechanically Ventilated Patients With Sepsis: A Systematic Review and Meta-Analysis

Purpose: Dexmedetomidine has been shown to improve clinical outcomes in critically ill patients. However, its effect on septic patients remains controversial. Therefore, the purpose of this meta-analysis was to assess the effect of dexmedetomidine as a sedative agent for mechanically ventilated patients with sepsis. Methods: We searched PubMed, Embase, Scopus, and Cochrane Library from inception through May 2021 for randomized controlled trials that enrolled mechanically ventilated, adult septic patients comparing dexmedetomidine with other sedatives or placebo. Results: A total of nine studies involving 1,134 patients were included in our meta-analysis. The overall mortality (RR 0.97, 95%CI 0.82 to 1.13, P = 0.67, I² = 25%), length of intensive care unit stay (MD -1.12, 95%CI -2.89 to 0.64, P = 0.21, I² = 71%), incidence of delirium (RR 0.95, 95%CI 0.72 to 1.25, P = 0.70, I² = 0%), and delirium free days (MD 1.76, 95%CI -0.94 to 4.47, P = 0.20, I² = 80%) were not significantly different between dexmedetomidine and other sedative agents. Alternatively, the use of dexmedetomidine was associated with a significant reduction in the duration of mechanical ventilation (MD -0.53, 95%CI -0.85 to -0.21, P = 0.001, I² = 0%) and inflammatory response (TNF-α: MD -5.27, 95%CI -7.99 to -2.54, P<0.001, I² = 0%; IL-1β: MD -1.25, 95%CI -1.91 to -0.59, P<0.001, I² = 0%). Conclusions: For patients with sepsis, the use of dexmedetomidine as compared with other sedative agents does not affect all-cause mortality, length of intensive care unit stay, the incidence of delirium, and delirium-free days. But the dexmedetomidine was associated with the reduced duration of mechanical ventilation and inflammatory response.

The Anti-inflammatory Effect of Dexmedetomidine Administration on Patients Undergoing Intestinal Surgery: A Randomized Study

BACKGROUND AND OBJECTIVE

Dexmedetomidine is a highly selective α2-adrenergic receptor agonist with sedative, analgesic, anti-sympathetic and stress-reducing effects. It has been widely used as an adjunct for general anesthesia of multiple surgeries. However, the relationship between the utilization of dexmedetomidine in intestinal surgery and the postoperative inflammatory response of patients remains unclear.

METHODS

A randomized, controlled, single-blinded clinical trial was performed. Eighty-six patients assigned for intestinal surgery were recruited and were randomly divided into two groups (dexmedetomidine group, n = 40; control group, n = 40) [six participants were excluded due to multiple reasons, such as allergy and drug use history]. The clinical characteristics and physiological outcomes of participants who received different treatments (dexmedetomidine and 0.9% sodium chloride) were collected and analyzed. Blood samples of the two groups were collected before administration (T0), 10 min after pumping dexmedetomidine/saline solution (T1), immediately after the operation started (T2), 30 min after the operation started (T3), and immediately after the operation ended (T4). Enzyme-linked immunosorbent assay (ELISA) was performed to evaluate the proinflammatory factors.

RESULTS

Intravenous injection of dexmedetomidine before intestinal surgery decreased a variety of circulating proinflammatory factors. Dexmedetomidine alleviated the stress response and promoted the recovery of cognitive ability among patients undergoing intestinal surgery.

CONCLUSION

Dexmedetomidine administration in patients undergoing intestinal surgery inhibited the surgery-induced inflammatory reactions.

How should dexmedetomidine and clonidine be prescribed in the critical care setting?

Cardiac, ventilatory and kidney management in the critical care setting has been optimized over the past decades. Cognition and sedation represent one of the last remaning challenges. As conventional sedation is suboptimal and as the sedation evoked by alpha-2 adrenergic agonists ("cooperative" sedation with dexmedetomidine, clonidine or guanfacine) represents a valuable alternative, this manuscript covers three practical topics for which evidence-based medicine is lacking: a) Switching from conventional to cooperative sedation ("switching"): the short answer is the abrupt withdrawal of conventional sedation, immediate implementation of alpha-2 agonist infusion and the use of "rescue sedation" (midazolam bolus[es]) or "breakthrough sedation" (haloperidol bolus[es]) to stabilize cooperative sedation. b) Switching from conventional to cooperative sedation in unstable patients (e.g., refractory delirium tremens, septic shock, acute respiratory distress syndrome, etc.): to avoid hypotension and bradycardia evoked by sympathetic deactivation, the short answer is to maintain the stroke volume through volume loading, vasopressors and inotropes. c) To avoid these switches and associated difficulties, alpha-2 agonists may be considered first-line sedatives. The short answer is to administer alpha-2 agonists slowly from admission or endotracheal intubation up to stabilized cooperative sedation. The "take home" message is as follows: a) alpha-2 agonists are jointly sympathetic deactivators and sedative agents; b) sympathetic deactivation implies maintaining the stroke volume and iterative assessment of volemia. Evidence-based medicine should document our propositions.

Effects of a BMI1008 mixture on postoperative pain in a rat model of incisional pain

Background

The purpose of this study was to evaluate the analgesic effect of BMI1008 (a new drug containing lidocaine, methylene blue, dexamethasone and vitamin B complex) and to investigate the analgesic effect of lidocaine and BMI-L (other components of BMI1008 except lidocaine) at different concentrations in a rat model of incisional pain.

Methods

Male Sprague-Dawley rats (250–300 g) were used for the incisional pain model simulating postoperative pain. After the operation, normal saline, various concentrations of BMI1008, lidocaine with a fixed concentration of BMI-L, and BMI-L with a fixed concentration of lidocaine were injected at the incision site. The preventive analgesic effect was evaluated using BMI1008 administered 30 min before and immediately after the operation. In addition, BMI1008 was compared with positive controls using intraperitoneal ketorolac 30 mg/kg and fentanyl 0.5 μg/kg. The mechanical withdrawal threshold was measured with a von Frey filament.

Results

The analgesic effect according to the concentration of BMI1008, lidocaine with a fixed concentration of BMI-L, and BMI-L with a fixed concentration of lidocaine showed a concentration-dependent response and statistically significant difference among the groups (P <0.001, P <0.001, and P <0.001, respectively). The analgesic effect according to the time point of administration (before and after the operation) showed no evidence of a statistically significant difference between the groups (P = 0.170). Compared with the positive control groups, the results showed a statistically significant difference between the groups (P = 0.024).

Conclusion

BMI1008 showed its analgesic effect in a rat model of incisional pain in a concentration-dependent manner. Moreover, BMI-L showed an additive effect on the analgesic effect of lidocaine.

Dexmedetomidine attenuates one-lung ventilation associated lung injury by suppressing inflammatory responses: A systematic review and meta-analysis

One-lung ventilation (OLV), a common ventilation technique, is associated with perioperative lung injury, tightly connected with inflammatory responses. Dexmedetomidine has shown positive anti-inflammatory effects in lung tissues in pre-clinical models. This study investigated the efficacy of dexmedetomidine for suppressing inflammatory responses in patients requiring OLV. We searched PubMed, MEDLINE, Embase, Scopus, Ovid, and Cochrane Library for randomized controlled trials focusing on dexmedetomidine's anti-inflammatory effects on patients requiring OLV without any limitation on the year of publication or languages. 20 clinical trials were assessed with 870 patients in the dexmedetomidine group and 844 in the control group. Our meta-analysis investigated the anti-inflammatory property of dexmedetomidine perioperatively [T1 (30-min OLV), T2 (90-min OLV), T3 (end of surgery) and T4 (postoperative day 1)], demonstrating that dexmedetomidine's intraoperative administration resulted in a significant reduction in serum concentration of interleukin-6, tumor necrosis factor-α and other inflammatory cytokines perioperatively. By calculating specific I2 index, significant heterogeneity was observed on all occasions, with I2 index ranging from 95% to 99%. For IL-6 changes, sensitivity analysis showed that the exclusion of a single study led to a significant decrease of heterogeneity (96%-0%; p < 0.00001). Besides, pulmonary oxygenation was ameliorated in the dexmedetomidine group comparing with the control group. In conclusion, perioperative administration of dexmedetomidine can attenuate OLV induced inflammation, ameliorate pulmonary oxygenation, and may be conducive to a decreased occurrence of postoperative complications and better prognosis. However, the results should be prudently interpreted due to the evidence of heterogeneity and the limited number of studies.

Dexmedetomidine Mitigated NLRP3-Mediated Neuroinflammation via the Ubiquitin-Autophagy Pathway to Improve Perioperative Neurocognitive Disorder in Mice

Background: Surgery and anesthesia-induced perioperative neurocognitive disorder (PND) are closely related to NOD-like receptors (NLR) family, pyrin domain containing 3 (NLRP3) inflammasome microglia inflammatory response. Inhibiting the occurrence of neuroinflammation is an important treatment method to improve postoperative delirium. Fewer NLRP3-targeting molecules are currently available in the clinic to reduce the incidence of postoperative delirium. Dexmedetomidine (DEX), an α2 adrenergic receptor agonist has been shown to have antioxidant and anti-inflammatory activities. The present study showed that DEX reduced the production of cleaved caspase1 (CASP1) and destroyed the NLRP3–PYD And CARD Domain Containing (PYCARD)–CASP1 complex assembly, thereby reducing the secretion of IL-1β interleukin beta (IL-1β). DEX promoted the autophagy process of microglia and reduced NLRP3 expression. More interestingly, it promoted the ubiquitination and degradation of NLRP3. Thus, this study demonstrated that DEX reduced NLRP3-mediated inflammation through the activation of the ubiquitin-autophagy pathway. This study provided a new mechanism for treating PND using DEX.

Methods: C57BL/6 mice were pre-administered DEX 3 days in advance, and an abdominal exploration model was used to establish a perioperative neurocognitive disorder model. The anti-inflammatory effect of DEX was explored in vivo by detecting NLRP3-CASP1/IL-1β protein expression and behavioral testing. Primary microglia were stimulated with lipopolysaccharide (LPS) and adenosine triphosphate (ATP) in vitro, the expression of CASP1 and IL-1β was detected in the supernatant of cells, and the expression of autophagy-related proteins microtubule-associated protein 1 light chain 3 beta (MAP1LC3B) and sequestosome 1 (SQSTM1) was examined in the cytoplasm. Meanwhile, Co-immunoprecipitation (Co-IP) was used to detect NLRP3 protein ubiquitination so as to clarify the new mechanism underlying the anti-inflammatory effect of DEX.

Results: Pre-administration of DEX reduced the protein expression of NLRP3, CASP1, and IL-1β in the hippocampus of mice induced by surgery and also improved the impairment of learning and memory ability. At the same time, DEX also effectively relieved the decrease in spine density of the hippocampal brain induced by surgery. DEX decreased the cleaved CASP1 expression, blocked the assembly of NLRP3–PYCARD–CASP1 complex, and also reduced the secretion of mature IL-1β in vitro. Mechanically, it accelerated the degradation of NLRP3 inflammasome via the autophagy–ubiquitin pathway and reduced the green fluorescent protein/red fluorescent protein MAP1LC3B ratio, which was comparable to the effect when using the autophagy activator rapamycin (Rapa). Furthermore, it increased the ubiquitination of NLRP3 after LPS plus ATP stimulated microglia.

Conclusion: DEX attenuated the hippocampal brain inflammation by promoting NLRP3 inflammasome degradation via the autophagy–ubiquitin pathway, thus improving cognitive impairment in mice.

Dexmedetomidine use and mortality in mechanically ventilated patients with severe burns: A cohort study using a national inpatient database in Japan

BACKGROUND

Dexmedetomidine is an alpha 2-adrenergic receptor agonist. Apart from its sedative effects, dexmedetomidine can potentially reduce mortality through its anti-inflammatory effect. However, the impact of dexmedetomidine on in-hospital outcomes of patients with severe burns remains unclear. Therefore, we aimed to elucidate the association between dexmedetomidine use and mortality in mechanically ventilated patients with severe burns, using a Japanese nationwide database of in-hospital patients.

METHODS

We included adults with severe burns (burn index ≥ 10) who were registered in the Japanese Diagnosis Procedure Combination national inpatient database from 2010 to 2018, started mechanical ventilation within 3 days of admission, and received any sedative drug (dexmedetomidine, midazolam, or propofol). One-to-one propensity score matching was performed between patients who received dexmedetomidine on the day of mechanical ventilation initiation (dexmedetomidine group) and those who did not receive dexmedetomidine (control group). The primary outcome was all-cause 30-day in-hospital mortality. Secondary outcomes were length of hospital stay and duration of mechanical ventilation in patients and survivors.

RESULTS

Eligible patients (n = 1888) were classified into the dexmedetomidine group (n = 371) or the control group (n = 1517). After one-to-one propensity score matching, we compared 329 patients from both groups. No significant difference was observed in the 30-day mortality between patients in the dexmedetomidine and control groups (22.8% vs. 22.5%, respectively; odds ratio, 1.02; 95% confidence interval, 0.71-1.46). Moreover, there were no significant differences between patients in the dexmedetomidine and control groups in terms of the length of hospital stay or the duration of mechanical ventilation.

CONCLUSIONS

We found no significant association between dexmedetomidine use and in-hospital outcomes (mortality, length of hospital stay, and length of mechanical ventilation) in mechanically ventilated patients with severe burns. Dexmedetomidine use may not improve the aforementioned outcomes; therefore, its selection should be based on the patient's general condition and the target level of sedation.

Dexmedetomidine ameliorates endotoxin-induced acute lung injury in vivo and in vitro by preserving mitochondrial dynamic equilibrium through the HIF-1a/HO-1 signaling pathway

Increasing lines of evidence identified that dexmedetomidine (DEX) exerted protective effects against sepsis-stimulated acute lung injury via anti-inflammation, anti-oxidation and anti-apoptosis. However, the mechanisms remain unclear. Herein, we investigated whether DEX afforded lung protection by regulating the process of mitochondrial dynamics through the HIF-1a/HO-1 pathway in vivo and in vitro. Using C57BL/6J mice exposed to lipopolysaccharide, it was initially observed that preemptive administration of DEX (50μg/kg) alleviated lung pathologic injury, reduced oxidative stress indices (OSI), improved mitochondrial dysfunction, upregulated the expression of HIF-1α and HO-1, accompanied by shifting the dynamic course of mitochondria into fusion. Moreover, HO-1-knockout mice or HO-1 siRNA transfected NR8383 cells were pretreated with HIF-1α stabilizer DMOG and DEX to validate the effect of HIF-1a/HO-1 pathway on DEX-mediated mitochondrial dynamics in a model of endotoxin-induced lung injury. We found that pretreatment with DEX and DMOG distinctly relieved lung injury, decreased the levels of mitochondrial ROS and mtDNA, reduced OSI, increased nuclear accumulation of HIF-1a and HO-1 protein in wild type mice but not HO-1 KO mice. Similar observations were recapitulated in NC siRNA transfected NR8383 cells after LPS stimulation but not HO-1 siRNA transfected cells. Concertedly, DEX reversed the impaired mitochondrial morphology in LPS stimulated-wild type mice or NC siRNA transfected NR8383 cells, upregulated the expression of mitochondrial fusion protein, while downregulated the expression of fission protein in HIF-1a/HO-1 dependent pathway. Altogether, our data both in vivo and in vitro certified that DEX treatment ameliorated endotoxin-induced acute lung injury by preserving the dynamic equilibrium of mitochondrial fusion/fission through the regulation of HIF-1a/HO-1 signaling pathway.

Dexmedetomidine Protects Against Septic Liver Injury by Enhancing Autophagy Through Activation of the AMPK/SIRT1 Signaling Pathway

Background: Liver injury is one of the serious complications of sepsis. Previous studies suggested that dexmedetomidine (DEX) could alleviate cecal ligation and puncture (CLP)-induced liver injury. However, it is unclear whether the protective effect of DEX on sepsis-induced liver injury is related to autophagy.

Methods: Mice (n = 105) were randomly divided into the following groups: (i) CON group (Sham); (ii) CLP group (CLP-induced liver injury + saline); (iii) CLP + DEX group (CLP-induced liver injury + DEX). Mouse models of sepsis-induced liver injury were established using CLP. DEX or normal saline was administered by intraperitoneal injection at 0, 2, and 4 h after CLP surgery. The mortality rate within 120 h was calculated. The levels of alanine aminotransferase (ALT), aspartate aminotransferase (AST), and inflammatory cytokines were measured at 6, 12, and 24 h in each group. Hematoxylin and eosin staining assay was carried out to detect the morphological changes of mouse liver cells in each group. The levels of autophagy-associated proteins LC3II, Beclin-1, p62, and LAMP-2 were detected in three groups of mice using western blotting. The expression of LC3II was detected using immunofluorescence. Transmission electron microscopy (TEM) of liver tissue was used to observe autophagosomes and autophagosome–lysosomes. Lastly, the effect of DEX on the AMPK/SIRT1 pathway-associated protein levels were detected using western blotting. Meanwhile, we used L0-2 cells infected with mRFP-GFP-LC3 adenovirus to further analyze the role of SIRT1 in DEX-induced autophagy in liver injury model in vitro.

Results: DEX significantly improved the survival rate of septic mice at the early stage and ameliorated the pathology of sepsis-induced liver injury. The level of autophagy-associated proteins, phosphorylated (p)-AMPK/AMPK, and SIRT1 in the liver of CLP-induced sepsis mice peaked at 12 h post-CLP and decreased significantly at 24 h. In the CLP + DEX group, the levels of autophagy-associated proteins, p-AMPK/AMPK, and SIRT1 increased, whereas inflammatory cytokines decreased at 24 h. The autophagosome structure was clearly observed at different time points in the CLP + DEX group. In the in vitro hepatocyte injury model, the SIRT1 inhibitor significantly increased intracellular ROS levels and reversed the effect of DEX on autophagy flux.

Conclusion: We demonstrated a novel mechanism in which DEX protects against CLP-induced liver injury. DEX enhances autophagy, which alleviates the inflammatory responses in CLP-induced liver injury by regulating the SIRT1/AMPK pathway.

Induced normothermia ameliorates the procoagulant host response in human endotoxaemia

Background

Dysregulation of coagulation occurs commonly in sepsis, ranging from mild coagulopathy with decreased platelets to disseminated intravascular coagulation (DIC). We investigated the effect of induced normothermia on coagulation during lipopolysaccharide (LPS)-induced endotoxaemia in healthy volunteers.

Methods

Twelve volunteers received an infusion of bacterial lipopolysaccharide (Escherichia coli; 2 ng kg⁻¹) and were assigned to either induced normothermia or control. Induced normothermia to maintain core temperature at 37°C consisted of external surface cooling, cold i.v. fluids, and medication to reduce shivering (buspirone, clonidine, and magnesium sulphate). The primary outcome was the DIC score (International Society on Thrombosis and Haemostasis guideline). Prothrombin time (PT), activated partial thromboplastin time (aPTT), D-dimer, plasma von Willebrand factor (vWf), and rotational thromboelastometry (ROTEM) were measured before and 1, 3, 6, and 8 h after LPS infusion. Differences between groups were tested with a mixed effects model.

Results

In control subjects, lipopolysaccharide caused a fever, transiently decreased platelet levels and lowered activated partial thromboplastin time, while prolonging prothrombin time and increasing D-Dimer and vWf levels. Normothermia prevented the DIC-score exceeding 4, which occurred in 50% of control subjects. Normothermia also reduced the fall in platelet count by 67x10⁹ L⁻¹([95%CI:27-107]; p=0.002), aPTT (mean difference:3s [95%CI:1-5]; p=0.005) and lowered vWf levels by 89% ([95%CI:6-172]; p=0.03), compared to the fever group. ROTEM measurements were unaffected by lipopolysaccharide.

Conclusion

In human endotoxaemia, induced normothermia decreases markers of endothelial activation and DIC. Maintaining normothermia may reduce coagulopathy in hyperinflammatory states.

Risk factors and socio-economic burden in pancreatic ductal adenocarcinoma operation: a machine learning based analysis

BACKGROUND

Surgical resection is the major way to cure pancreatic ductal adenocarcinoma (PDAC). However, this operation is complex, and the peri-operative risk is high, making patients more likely to be admitted to the intensive care unit (ICU). Therefore, establishing a risk model that predicts admission to ICU is meaningful in preventing patients from post-operation deterioration and potentially reducing socio-economic burden.

METHODS

We retrospectively collected 120 clinical features from 1242 PDAC patients, including demographic data, pre-operative and intra-operative blood tests, in-hospital duration, and ICU status. Machine learning pipelines, including Supporting Vector Machine (SVM), Logistic Regression, and Lasso Regression, were employed to choose an optimal model in predicting ICU admission. Ordinary least-squares regression (OLS) and Lasso Regression were adopted in the correlation analysis of post-operative bleeding, total in-hospital duration, and discharge costs.

RESULTS

SVM model achieved higher performance than the other two models, resulted in an AU-ROC of 0.80. The features, such as age, duration of operation, monocyte count, and intra-operative partial arterial pressure of oxygen (PaO2), are risk factors in the ICU admission. The protective factors include RBC count, analgesic pump dexmedetomidine (DEX), and intra-operative maintenance of DEX. Basophil percentage, duration of the operation, and total infusion volume were risk variables for staying in ICU. The bilirubin, CA125, and pre-operative albumin were associated with the post-operative bleeding volume. The operation duration was the most important factor for discharge costs, while pre-lymphocyte percentage and the absolute count are responsible for less cost.

CONCLUSIONS

We observed that several new indicators such as DEX, monocyte count, basophil percentage, and intra-operative PaO2 showed a good predictive effect on the possibility of admission to ICU and duration of stay in ICU. This work provided an essential reference for indication in advance to PDAC operation.

Effect of dexmedetomidine on hemodynamic changes and inflammatory responses in patients undergoing off-pump coronary-artery bypass grafting

The aim of the present study was to determine the effect of dexmedetomidine on hemodynamic changes and inflammatory responses in patients undergoing off-pump coronary artery bypass grafting (OPCABG). A total of 300 patients about to receive OPCABG were randomized evenly into the control group (n=116) and study group (n=123). Intravenous dexmedetomidine pump infusion was administered to patients in the study group at a rate of 0.4 µg.kg^-1.h^-1. The control group received physiological saline at the same infusion speed. Changes in hemodynamic parameters and inflammatory indices were compared between the two groups. Hemodynamic parameters, such as the heart rate and mean arterial pressure, were lower in patients from the study group, compared with that in the control group (both P<0.05). The levels of pro-inflammatory factors, such as interleukin (IL)-6, tumor necrosis factor-α and C-reactive protein, were also reduced in the study group (P<0.05). The observed levels of IL-10 were lower in the control group compared with that in the study group, although a statistically significant difference was not achieved. Thus, the administration of dexmedetomidine in patients undergoing OPCABG stabilized hemodynamics and reduced inflammation. The present study was registered at the Chinese Clinical Trial Registry, under the trial registration number ChiCTR-OOC-15005978 (2015).

Effect of Dexmedetomidine on Postoperative Lung Injury during One-Lung Ventilation in Thoracoscopic Surgery

Objective

To investigate the effect of dexmedetomidine on postoperative lung injury in patients undergoing thoracoscopic surgery.

Methods

From March 2019 to October 2019, 40 patients were randomly divided into two groups: dexmedetomidine group (group D) and control group (group C). Except recording the general condition of the patients in both groups preoperatively and intraoperatively, the oxygenation index (OI) and alveolar-arterial oxygen partial pressure difference (A-aDO₂) were monitored at admission (T0), immediately after one-lung ventilation (T1), 0.5 h after one-lung ventilation (T2), and 15 minutes after inhaling air before leaving the room (T3). The content of IL-8 in arterial blood was measured by enzyme-linked immunosorbent assay (ELISA) at T0 and T2, and the expression of AQP1 protein in isolated lung tissue was measured by immunohistochemistry and Western blot. The incidence of postoperative pulmonary complications (atelectasis, pneumonia, and acute respiratory distress syndrome) was used as the index of lung injury.

Results

There was no significant difference in the general condition before and during operation between the two groups. There was no significant difference in arterial blood IL-8 content between the two groups at the T0 time point, but the arterial blood IL-8 content at the T2 time point was significantly higher than that at the T0 time point, especially in group C. The results of immunohistochemistry and Western blot showed that the expression level of AQP1 protein in the isolated lung tissue of group D was significantly higher than that of group C (P < 0 05). At T3, the OI of group D was significantly higher than that of group C, and the A-aDO₂ of group D was significantly lower than that of group C (P < 0.05). There was no significant difference in the incidence of postoperative PPCs between the two groups.

Conclusion

Dexmedetomidine can reduce the level of plasma IL-8 and upregulate the expression of AQP1 in the lung tissue of patients undergoing thoracoscopic surgery under one-lung ventilation, but it has no significant effect on the incidence of postoperative PPCs. Dexmedetomidine can be safely used in thoracoscopic surgery and has a certain protective effect on lung injury.

Dexmedetomidine and Mortality From Sepsis Requiring Mechanical Ventilation: A Japanese Nationwide Retrospective Cohort Study

BACKGROUND

Dexmedetomidine has a mild sedative effect and may reduce mortality in mechanically ventilated critically ill patients. However, few studies have examined the effects of dexmedetomidine in patients with sepsis who require mechanical ventilation. The aim of this study was to investigate the association between dexmedetomidine and mortality in patients with sepsis requiring mechanical ventilation, using a nationwide inpatient database in Japan.

METHODS

Using the Diagnosis Procedure Combination database from July 1, 2010, to March 31, 2016, we identified adult patients with sepsis who required mechanical ventilation for more than 2 days. Patients were divided into those who received dexmedetomidine and those who received midazolam or propofol within 1 day after admission. Logistic regression analysis, propensity score-matched analysis, and instrumental variable analysis were performed to compare all-cause 28-day mortality and duration of mechanical ventilation between the groups.

RESULTS

In total, 50 671 were eligible patients, including dexmedetomidine group (n = 13 759) and propofol or midazolam group (n = 36 912). The dexmedetomidine group had significantly lower all-cause 28-day mortality compared with the group receiving midazolam or propofol, as shown by the logistic regression analysis (odds ratio [OR]: 0.78; 95% confidence interval [CI]: 0.73-0.84), the propensity score-matched analysis (OR: 0.85; 95% CI: 0.80-0.91), and the instrumental variable analysis (OR: 0.64; 95% CI: 0.57-0.73). The duration of mechanical ventilation in the dexmedetomidine group was significantly shorter than that in the midazolam or propofol group.

CONCLUSIONS

Dexmedetomidine was associated with a reduction in all-cause 28-day mortality and duration of mechanical ventilation.