Dexmedetomidine reduces intestinal and hepatic injury after hepatectomy with inflow occlusion under general anaesthesia: a randomized controlled trial

Impact of intravenous dexmedetomidine on postoperative gastrointestinal function recovery: an updated meta-analysis

BACKGROUND

Postoperative ileus (POI) is a complication that may occur after abdominal or nonabdominal surgery. Intravenous dexmedetomidine (Dex) has been reported to accelerate postoperative gastrointestinal function recovery; however, updated evidence is required to confirm its robustness.

METHODS

To identify randomized controlled trials examining the effects of perioperative intravenous Dex on gastrointestinal function recovery in patients undergoing noncardiac surgery, databases including MEDLINE, EMBASE, Google Scholar, and Cochrane Library were searched on August 2023. The primary outcome was time to first flatus. Secondary outcomes included time to oral intake and defecation as well as postoperative pain scores, postoperative nausea/vomiting (PONV), risk of hemodynamic instability, and length of hospital stay (LOS). To confirm its robustness, subgroup analyses and trial sequential analysis were performed.

RESULTS

The meta-analysis of 22 randomized controlled trials with 2566 patients showed that Dex significantly reduced the time to flatus [mean difference (MD):-7.19 h, P <0.00001), time to oral intake (MD: -6.44 h, P =0.001), time to defecation (MD:-13.84 h, P =0.008), LOS (MD:-1.08 days, P <0.0001), and PONV risk (risk ratio: 0.61, P <0.00001) without differences in hemodynamic stability and pain severity compared with the control group. Trial sequential analysis supported sufficient evidence favoring Dex for accelerating bowel function. Subgroup analyses confirmed the positive impact of Dex on the time to flatus across different surgical categories and sexes. However, this benefit has not been observed in studies conducted in regions outside China.

CONCLUSIONS

Perioperative intravenous Dex may enhance postoperative gastrointestinal function recovery and reduce LOS, thereby validating its use in patients for whom postoperative ileus is a significant concern.

Dexmedetomidine and acute kidney injury after non-cardiac surgery: A meta-analysis with trial sequential analysis

BACKGROUND

Acute kidney injury (AKI) is a common complication after surgery and is associated with detrimental outcomes. This systematic review and meta-analysis evaluated perioperative dexmedetomidine on AKI and renal function after non-cardiac surgery.

METHODS

PubMed, Embase, and Cochrane Library databases were searched until August 2023 for randomised trials comparing dexmedetomidine with normal saline on AKI and renal function in adults undergoing non-cardiac surgery. The primary outcome was the incidence of AKI (according to Kidney Disease Improving Global Outcomes or Acute Kidney Injury Network criteria). Meta-analysis was performed using a random-effect model. We conducted sensitivity analysis, trial sequential analysis (TSA), and Grading of Recommendations Assessment, Development and Evaluation level of evidence.

RESULTS

Twenty-three trials involving 2440 patients were included. Dexmedetomidine administration, as compared to normal saline, significantly reduced the incidence of AKI (7.4% vs. 13.2%; risk ratio = 0.57, 95% CI = 0.40-0.83, P =  0.003, I2 = 0%; a high level of evidence); TSA and sensitivity analyses suggested the robustness of this outcome. For the renal function and inflammation parameters, dexmedetomidine decreased serum creatinine, blood urea nitrogen, cystatin C, tumour necrosis factor-α, and interleukin-6, and increased urine output and estimated glomerular filtration rate. Additionally, dexmedetomidine reduced postoperative nausea and vomiting and length of hospital stay. Dexmedetomidine was associated with an increased rate of bradycardia, but not hypotension.

CONCLUSION

Dexmedetomidine administration reduced the incidence of AKI and improved renal function after non-cardiac surgery. Based on a high level of evidence, dexmedetomidine is recommended as a component of perioperative renoprotection.

REGISTRATION

International Prospective Register of Systematic Reviews; Registration number: CRD42022299252.

Regulated cell death and inflammasome activation in gut injury following traumatic surgery in vitro and in vivo: implication for postoperative death due to multiorgan dysfunction

Postoperative multi-organ dysfunction (MOD) is associated with significant mortality and morbidity. Necroptosis has been implicated in different types of solid organ injury; however, the mechanisms linking necroptosis to inflammation require further elucidation. The present study examines the involvement of necroptosis and NLR family pyrin domain containing 3 (NLRP3) inflammasome in small intestine injury following traumatic surgery. Kidney transplantation in rats and renal ischaemia-reperfusion (I/R) in mice were used as traumatic and laparotomic surgery models to study necroptosis and inflammasome activation in the small intestinal post-surgery; additional groups also received receptor-interacting protein kinase 1 (RIPK1) inhibitor necrostatin-1s (Nec-1s). To investigate whether necroptosis regulates inflammasome activity in vitro, necroptosis was induced in human colonic epithelial cancer cells (Caco-2) by a combination of tumour necrosis factor-alpha (TNFα), SMAC mimetic LCL-161 and pan-caspase inhibitor Q-VD-Oph (together, TLQ), and necroptosis was blocked by Nec-1s or mixed lineage kinase-domain like (MLKL) inhibitor necrosulfonamide (NSA). Renal transplantation and renal ischaemia-reperfusion (I/R) upregulated the expression of necroptosis mediators (RIPK1; RIPK3; phosphorylated-MLKL) and inflammasome components (P2X purinoceptor subfamily 7, P2X7R; NLRP3; caspase-1) in the small intestines at 24 h, and Nec-1s suppressed the expression of inflammasome components. TLQ treatment induced NLRP3 inflammasome, promoted cleavage of caspase-1 and interleukin-1 beta (IL-1β), and stimulated extracellular ATP release from Caco-2 cells, and MLKL inhibitor NSA prevented TLQ-induced inflammasome activity and ATP release from Caco-2 cells. Our work suggested that necroptosis and inflammasome interactively promote remote postoperative small intestinal injury, at least in part, through ATP purinergic signalling. Necroptosis-inflammasome axis may be considered as novel therapeutic target for tackling postoperative MOD in the critical care settings.

Effect of inferior vena cava respiratory variability-guided fluid therapy after laparoscopic hepatectomy: a randomized controlled clinical trial

BACKGROUND

After major liver resection, the volume status of patients is still undetermined. However, few concerns have been raised about postoperative fluid management. We aimed to compare gut function recovery and short-term prognosis of the patients after laparoscopic liver resection (LLR) with or without inferior vena cava (IVC) respiratory variability-directed fluid therapy in the anesthesia intensive care unit (AICU).

METHODS

This randomized controlled clinical trial enrolled 70 patients undergoing LLR. The IVC respiratory variability was used to optimize fluid management of the intervention group in AICU, while the standard practice of fluid management was used for the control group. The primary outcome was the time to flatus after surgery. The secondary outcomes included other indicators of gut function recovery after surgery, postoperative length of hospital stay (LOS), liver and kidney function, the severity of oxidative stress, and the incidence of severe complications associated with hepatectomy.

RESULTS

Compared with patients receiving standard fluid management, patients in the intervention group had a shorter time to anal exhaust after surgery (1.5 ± 0.6 days vs. 2.0 ± 0.8 days) and lower C-reactive protein activity (21.4 [95% confidence interval (CI): 11.9-36.7] mg/L vs. 44.8 [95%CI: 26.9-63.1] mg/L) 24 h after surgery. There were no significant differences in the time to defecation, serum concentrations of D-lactic acid, malondialdehyde, renal function, and frequency of severe postoperative complications as well as the LOS between the groups.

CONCLUSION

Postoperative IVC respiratory variability-directed fluid therapy in AICU was facilitated in bowel movement but elicited a negligible beneficial effect on the short-term prognosis of patients undergoing LLR.

TRIAL REGISTRATION

ChiCTR-INR-17013093.

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.

Advances in the Clinical Application of Histamine and Diamine Oxidase (DAO) Activity: A Review

The serum level of diamine oxidase (DAO) reflects the integrity and maturation of the small intestinal mucosa. This measure is important in diagnosing various diseases, including chronic urticaria tachyphylaxis, multiple organ dysfunction syndrome, preterm abortion, and migraine. This review aimed to summarize the findings of previous studies on the changes in DAO levels in diverse diseases and the application of this enzyme in the clinical setting, as well as the roles of this enzyme under physiological and pathological conditions. The advances in the mechanism and clinical application of DAO presented in this review will contribute to a better understanding of this enzyme and open up new and broader perspectives for future basic research and clinical applications.

Effects of perioperative dexmedetomidine infusion on renal function and microcirculation in kidney transplant recipients: a randomised controlled trial

OBJECTIVE

Ischemia-reperfusion injury affects postoperative transplanted kidney function in kidney transplant recipients. Dexmedetomidine was reported to attenuate ischemia-reperfusion injury and improve microcirculation, but its propensity to cause bradycardia and hypotension may adversely affect microcirculation. This study investigated the effect of dexmedetomidine on postoperative renal function and sublingual microcirculation in kidney recipients.

METHODS

The enrolled kidney transplant recipients were randomly allocated to the control group or dexmedetomidine group. After anaesthesia induction, patients in the dexmedetomidine group received dexmedetomidine infusion until 2 h after surgery. Sublingual microcirculation was recorded using an incident dark-field video microscope and analysed. The primary outcomes were the creatinine level on a postoperative day 2 and total vessel density at 2 h after surgery.

RESULTS

A total of 60 kidney recipients were analysed, and the creatinine levels on postoperative day 2 were significantly lower in the dexmedetomidine group than in the control group (1.5 (1.1-2.4) vs. 2.2 (1.7-3.0) mg/dL, median difference -0.6 (95% CI, -0.7 to -0.5) mg/dL, p = .018). On a postoperative day 7, the creatinine levels did not differ significantly between the two groups. Total vessel density at 2 h after surgery did not differ significantly between the two groups.

CONCLUSION

We found that early postoperative renal function was better in kidney transplant recipients receiving dexmedetomidine infusion, but total vessel density was not significantly different between the intervention and control groups. Key messagesIschemia-reperfusion injury affects postoperative transplanted kidney function, and dexmedetomidine was reported to attenuate ischemia-reperfusion injury and improve microcirculation in other clinical conditions.This study showed that early postoperative renal function was better in kidney transplant recipients receiving dexmedetomidine.Dexmedetomidine's side effect of bradycardia and hypotension may affect microcirculation, our results revealed that the perioperative sublingual microcirculation did not differ significantly in kidney transplant recipients receiving dexmedetomidine.

Influence of Dexmedetomidine on Myocardial Injury in Patients with Simultaneous Pancreas-Kidney Transplantation

Background

Diabetes is one of the most common chronic diseases in the world. End-stage renal disease (ESRD) caused by diabetes is the most serious long-term complication. The main cause of death in patients with simultaneous pancreas-kidney transplantation (SPKT) is cardiovascular disease. Although dexmedetomidine (Dex) has unique advantages in heart protection against ischaemic/reperfusion injury, few clinical studies have been conducted on its cardioprotective effect in SPKT. This study aimed to explore the influence of Dex on myocardial injury in patients undergoing SPKT and to analyze its possible mechanism.

Methods

A randomized controlled trial (RCT) was performed from July 1, 2018 to December 1, 2020. Eighty patients, regardless of gender, scheduled for SPKT were randomly allocated into a Dex group (D group) receiving Dex at a rate of 1 µg/kg for 10 minutes before anaesthesia induction and then continuous infusion at 0.5 µg/kg/hour until the end of surgery and control group (C group) receiving equivalent capacity of saline. Serum cardiac troponin I (cTnI), creatine kinase isoenzyme (CK-MB), tumour necrosis factor-α (TNF-α), and interleukin-6 (IL-6) were recorded at 5 minutes after anaesthesia induction (baseline,T0), 5 minutes before renal arteriovenous opening (T1), 30 minutes after renal arteriovenous opening (T2), 30 minutes after pancreatic related arteriovenous opening (T3), immediately after surgery (T4), 4 hours after surgery (T5), and 24 hours after surgery (T6). Adverse cardiovascular events were recorded during the perioperative period. Changes in ECG S-T segments and T waves were monitored at T0-T6. Myocardial infarction and percutaneous coronary intervention were recorded with an average follow-up of one year.

Results

Compared with T0, TNF-α and IL-6 concentrations significantly increased at T1-T6 in the C and D groups (P < 0.05). IL-6 concentration increased significantly after renal artery opening and reached the peak after the opening of pancreatic blood vessels. Compared with the C group, TNF-α, and IL-6 concentrations were significantly reduced in group D at T2-T6 (P < 0.05). Compared with T0, cTnI and CK-MB concentrations were significantly increased at T3-T6 in the C and D groups (P < 0.05). cTnI and CK-MB concentrations increased significantly after the opening of renal artery, and reached the peak after the opening of pancreatic blood vessels. Compared with the C group, cTnI and CK-MB concentrations were significantly reduced in the D group at T3-T6 (P < 0.05). There was no significant difference in patient characteristics amongst groups, including the proportion of intraoperative vasoactive drug use and adverse cardiovascular events during the follow-up period. Heart rate, mean blood pressure, central venous pressure, and cardiac output were not remarkably different between the two groups at any time point.

Conclusions

Perioperative reperfusion could aggravate myocardial injury in SPKT. Dex may be considered a way to reduce myocardial injury caused by inflammatory action by decreasing the release of inflammatory factors. Trial Registration Number: Chinese Clinical Trial Registry ID: ChiCTR2200060084.

Study on the protective mechanism of dexmedetomidine on the liver of perioperative diabetic patients: A randomized controlled trial

BACKGROUND

Although several studies have reported that dexmedetomidine is a highly selective α2-adrenergic receptor agonist that protects liver function in perioperative patients by inhibiting oxidative stress (OS) and inflammatory response, patients with type 2 diabetes mellitus (T2DM) have not been included in the previous studies. The purpose of this study was to investigate the effects of perioperative low-dose dexmedetomidine on perioperative liver function in T2DM patients.

METHODS

This was a single-center, placebo-controlled randomized trial. Fifty-four T2DM patients scheduled for debridement of lower extremity ulcers were included in this study and randomly divided into 2 groups (n = 27 per group): the dexmedetomidine group (DEX group) and the control group (CON group). Continuous intravenous infusion of dexmedetomidine (DEX group) or normal saline (CON group) was administered from the completion of monitoring to the end of surgery. All participants received femoral and sciatic nerve block with 0.33% ropivacaine. The main result was the activity of liver enzymes (AST, ALT) reflecting liver function. The secondary results included variables reflecting blood glucose (Glu), blood lipids (TG, HDL, LDL, total cholesterol), biomarkers of OS (MDA, SOD), and systemic inflammatory response (TNF-α, IL-6).

RESULTS

Compared with CON group, DEX group exhibited a reduction in hemodynamic parameters, Glu, systemic inflammatory response, and liver injury indicators. OS response MDA activity was lower in DEX group than in CON group, while SOD was higher than that in CON group. The variables reflecting lipid metabolism function showed no differences between the groups.

CONCLUSION SUBSECTIONS

Dexmedetomidine administered perioperatively can reduce Glu levels and protect the liver by attenuating OS injury and inflammatory response in T2DM patients without any potential risk.

The Role of Dexmedetomidine in Tumor-Progressive Factors in the Perioperative Period and Cancer Recurrence: A Narrative Review

Dexmedetomidine, a specific α2 adrenergic receptor agonist, is highly frequently used in the perioperatively for its favorable pharmacology, such as mitigating postoperative cognitive dysfunction. Increasing attention has been recently focused on the effect of whether dexmedetomidine influences cancer recurrence, which urges the discussion of the role of dexmedetomidine in tumor-progressive factors. The pharmacologic characteristics of dexmedetomidine, the tumor-progressive factors in the perioperative period, and the relationships between dexmedetomidine and tumor-progressive factors were described in this review. Available evidence suggests that dexmedetomidine could reduce the degree of immune function suppression, such as keeping the number of CD3+ cells, NK cells, CD4+/CD8+ ratio, and Th1/Th2 ratio stable and decreasing the level of proinflammatory cytokine (interleukin 6 and tumor necrosis factor-alpha) during cancer operations. However, dexmedetomidine exhibits different roles in cell biological behavior depending on cancer cell types. The conclusions on whether dexmedetomidine would influence cancer recurrence could not be currently drawn for the lack of strong clinical evidence. Therefore, this is still a new area that needs further exploration.

Comparison of effects of dexmedetomidine and amifostine against X-ray radiation-induced parotid damage

Radiotherapy can be employed as a therapeutic modality alone in the early stages of cancer and is used together with other treatments such as surgery and chemotherapy in more advanced stages. However, exposure to ionizing radiation in association with radiotherapy affects several organs in the head and neck and can give rise to early and late side effects. Exposure to ionizing radiation used in radiotherapy is known to cause cell damage by leading to oxygen stress through the production of free oxygen radicals (such as superoxide radicals, hydroxyl radical, hydrogen peroxide, and singlet oxygen), depending on the total radiation dosage, the fractionation rate, radiosensitivity, and linear energy transfer. The purpose of the present study was to determine the potential protective role of a powerful and highly selective α2-adrenoreceptor agonist with a broad pharmacological spectrum against salivary gland damage induced by ionizing radiation exposure. Forty Sprague-Dawley rats were divided into five groups-control, ionizing radiation, ionizing radiation + dexmedetomidine (100 µg/kg), ionizing radiation + dexmedetomidine (200 µg/kg), and ionizing radiation + amifostine (200 mg/kg). Following exposure to ionizing radiation, we observed necrosis, fibrosis, and vascular congestions in parotid gland epithelial cells. We also observed increases in malondialdehyde (MDA) and cleaved Caspase-3 levels and a decrease in glutathione (GSH). In groups receiving dexmedetomidine, we observed necrotic epithelial cells, fibrosis and vascular congestion in parotid gland tissue, a decrease in MDA levels, and an increase in GSH. Dexmedetomidine may be a promising antioxidant agent for the prevention of oxidative damage following radiation exposure.

Effect and Mechanism of Lidocaine Pretreatment Combined with Dexmedetomidine on Oxidative Stress in Patients with Intracranial Aneurysm Clipping

This study aimed to explore the effect and mechanism of lidocaine pretreatment combined with dexmedetomidine on oxidative stress in patients with intracranial aneurysm clipping. Many studies have used various drugs such as lidocaine to explore the effect and mechanism of lidocaine pretreatment. A total of 80 patients with intracranial aneurysm clipping surgery were randomly divided into 4 groups: the single lidocaine group, single dexmedetomidine group, lidocaine combined with dexmedetomidine group, and control group. The thread embolism method was used to establish a stable intracranial aneurysm model of Hashimoto rats. Fifty adult rats were randomly divided into a sham operation group, ligation of the left common carotid artery and bilateral posterior branch of renal artery, lidocaine group, dexmedetomidine group, and lidocaine combined with dexmedetomidine group. The colorimetric method was used to determine the oxidative stress indicators in brain tissue: MDA content, SOD activity, and T-AOC content. The western blot method characterized the protein levels related to oxidative stress: nNOS, iNOS, and NADPH oxidase subunits p22phox, gp91phox, and p47phox. The differences in each index between the groups were statistically significant (P < 0.05). Animal experiment results revealed that the content of MDA in the brain tissue of rats in the LD group was significantly lower than that in the single-drug group and sham group. The T-AOC and SOD concentrations in the LD group were significantly higher than those in the single-drug group and sham group, and the differences between the groups were statistically significant (P < 0.05). The protein expression of the LD group was significantly lower than that of the drug-alone group and model group, and the difference between groups was statistically significant (P < 0.05). To sum up, lidocaine pretreatment combined with dexmedetomidine can effectively maintain the hemodynamic stability of patients with intracranial aneurysm clipping and reduce postoperative oxidative stress response. Its mechanism of action may be related to the inhibition of oxidative stress damage mediated by nNOS, iNOS, and p22phox, gp91phox, and p47phox in the hippocampus. Our study has significant and applicable medical aspects in lidocaine pretreatment combined with dexmedetomidine on oxidative stress in patients.

The Protective Effect of Dexmedetomidine Against Ischemia-Reperfusion Injury after Hepatectomy: A Meta-Analysis of Randomized Controlled Trials

Background: Hepatic inflow occlusion proceeded to reduce blood loss during hepatectomy induces ischemia-reperfusion (IR) injury in the remnant liver. Dexmedetomidine, a selective α₂-adrenoceptor agonist used as an anesthetic adjuvant, has been shown to attenuate IR injury in preclinical and clinical studies. However, a meta-analysis is needed to systematically evaluate the protective effect of perioperative dexmedetomidine use on IR injury induced by hepatectomy.

Methods: A prospectively registered meta-analysis following Cochrane and PRISMA guidelines concerning perioperative dexmedetomidine use on IR injury after hepatectomy was performed via searching Cochrane Library, PubMed, EMBASE, ClinicalTrials.gov, Web of Science, CNKI, WanFang, and Sinomed for eligible randomized controlled trials up to 2021.3.31. The main outcome is postoperative liver function. Risk of bias was assessed by the Cochrane Risk of Bias tool. Review Manager 5.3 and Stata12.0 were applied to perform data analyses.

Results: Eight RCTs enrolling 468 participants were included. Compared with 0.9% sodium chloride, dexmedetomidine decreased serum concentration of ALT (WMD = −66.54, 95% CI: −92.10–−40.98), AST (WMD= −82.96, 95% CI: −106.74–−59.17), TBIL (WMD = −4.51, 95% CI: −7.32–−1.71), MDA (WMD = −3.09, 95% CI: −5.17–−1.01), TNF-α (WMD = −36.54, 95% CI: −61.33–−11.95) and IL-6 (WMD = −165.05, 95% CI: −225.76–−104.34), increased SOD activity (WMD = 24.70, 95% CI: 18.09–31.30) within postoperative one day. There was no significant difference in intraoperative or postoperative recovery parameters between groups.

Conclusions: Perioperative administration of dexmedetomidine can exert a protective effect on liver IR injury after hepatectomy. Additional studies are needed to further evaluate postoperative recovery outcomes of dexmedetomidine with different dosing regimens.

Present and Future Therapeutic Approaches to Barrier Dysfunction

There is converging and increasing evidence, but also uncertainty, for the role of abnormal intestinal epithelial barrier function in the origin and development of a growing number of human gastrointestinal and extraintestinal inflammatory disorders, and their related complaints. Despite a vast literature addressing factors and mechanisms underlying changes in intestinal permeability in humans, and its connection to the appearance and severity of clinical symptoms, the ultimate link remains to be established in many cases. Accordingly, there are no directives or clinical guidelines related to the therapeutic management of intestinal permeability disorders that allow health professionals involved in the management of these patients to carry out a consensus treatment based on clinical evidence. Instead, there are multiple pseudoscientific approaches and commercial propaganda scattered on the internet that confuse those affected and health professionals and that often lack scientific rigor. Therefore, in this review we aim to shed light on the different therapeutic options, which include, among others, dietary management, nutraceuticals and medical devices, microbiota and drugs, and epigenetic and exosomes-manipulation, through an objective evaluation of the scientific publications in this field. Advances in the knowledge and management of intestinal permeability will sure enable better options of dealing with this group of common disorders to enhance quality of life of those affected.

Intraoperative Low-Dose Dexmedetomidine Administration Associated with Reduced Hepatic Ischemia-Reperfusion Injury in Pediatric Deceased Liver Transplantation: A Retrospective Cohort Study

Background

Dexmedetomidine (DEX) attenuates hepatic ischemia-reperfusion injury (HIRI) in adult liver transplantation (LT), but its effects on postoperative liver graft function in pediatric LT remain unclear. We sought to investigate whether intraoperative DEX administration was associated with improved liver graft function in pediatric LT recipients. It was hypothesized that DEX administration was associated with reduced HIRI and improved liver graft function.

Material/Methods

From November 2015 to May 2020, 54 deceased pediatric LT recipients were categorized into a control group and a DEX group. Intraoperatively, the DEX group received an additional infusion of DEX at 0.4 μg/kg/h from incision to the end of the operation in comparison with the control group. Preoperative, intraoperative, and postoperative data were reviewed. Postoperative liver enzyme levels and HIRI severity were assessed and compared. Independent risk factors for HIRI were determined by multivariate logistic regression analysis using a stepwise forward conditional method.

Results

We enrolled 28 and 26 patients in the DEX and control groups, respectively. Patients in the DEX group exhibited a reduced incidence of moderate-to-severe HIRI (88.5% vs 60.7%, P=0.020) and decreased level of serum alanine aminotransferase (median [interquartile range]: 407 [230–826] vs 714 [527–1492] IU/L, P=0.048) compared with the controls. Binary logistic analysis revealed that longer cold ischemia time (odds ratio [OR]=1.006; 95% confidence interval [CI]=1.000–1.013; P=0.044) and intraoperative DEX use (OR=0.198; 95% CI=0.045–0.878; P=0.033) were independent predictors for moderate-to-severe HIRI.

Conclusions

Intraoperative low-dose DEX administration was associated with a lower incidence of moderate-to-severe HIRI in pediatric deceased LT. However, further studies are needed to confirm our results and elucidate the underlying mechanisms.

The effect of dexmedetomidine on renal function after surgery: A systematic review and meta-analysis

WHAT IS KNOWN AND OBJECTIVE

Acute kidney injury (AKI) is a complication following surgery and has been associated with worsened patient outcomes. Providers have used agents that may confer a degree of renal protection in the perioperative stage. Such is the case of dexmedetomidine, a selective alpha-2 adrenergic agonist used in the intensive care unit (ICU) as a sedative agent. The primary objective of this meta-analysis was to characterize the use of dexmedetomidine and to evaluate its impact on renal markers and outcomes in patients after surgery.

METHODS

A systematic review of manuscripts was performed to identify patients who received dexmedetomidine after surgery by searching the PubMed, Embase, and Cochrane databases. The following parameters were captured: blood urea nitrogen (BUN), serum creatinine, creatinine clearance, neutrophil gelatinase-associated lipoprotein (NGAL), cystatin C, urine output, duration of mechanical ventilation, ICU length of stay, AKI, need for dialysis, and mortality.

RESULTS AND DISCUSSION

Nineteen studies with 3,395 patients were included in the analyses. The mean bolus and infusion dose of dexmedetomidine were 0.82 µg/kg and 0.54 mcg/kg/hr, respectively. There was a significant difference in creatinine clearance and NGAL in favour of the dexmedetomidine group. In addition, the dexmedetomidine group had a shorter ICU length of stay, and a lower risk of acute kidney injury and mortality compared to the control. There was no difference in the rest of the parameters.

WHAT IS NEW AND CONCLUSION

Dexmedetomidine appears to have postoperative renal protective effects. This is evidenced by lower NGAL levels and increased creatinine clearance in those who received dexmedetomidine. These effects are associated with decreases in ICU length of stay and risk of AKI and mortality.

Effects of Dexmedetomidine on Patients Undergoing Laparoscopic Surgery for Colorectal Cancer

BACKGROUND

Pneumoperitoneum during laparoscopic surgery has a systemic impact on the renal system and might contribute to acute kidney injury or postoperative renal dysfunction. However, effective preventive strategies are still lacking. We aimed to explore the effects of dexmedetomidine (DEX) on kidney and other organ function in patients undergoing elective laparoscopic surgery for colorectal cancer.

MATERIALS AND METHODS

Fifty-six patients were randomly enrolled into the Control or DEX group. The DEX group received 1 µg kg^-1 DEX intravenously within 10 min followed by a maintenance dose of 0.5 µg kg^-1 h^-1 infused until 30 min before closing the peritoneum. In the Control group, 0.9% sodium chloride was administered as a placebo. The primary outcome was serum neutrophil gelatinase-associated lipocalin (NGAL) levels reflecting kidney injury. Secondary outcomes included variables reflecting the kidney, intestinal injury and systemic inflammatory response.

RESULTS

NGAL levels were significantly lower in the DEX group than in the Control group at 1 d and 5 d postoperatively (107.5 ± 55.6 ng mL^-1versus 179.5 ± 78.2 ng mL^-1; 70.3 ± 45.8 ng mL^-1versus 135.2 ± 59.6 ng mL^-1, P < 0.001), while the BUN and Cr levels showed no differences between the groups. Serum DAO activity was significantly lower in the DEX group patients 24 h after surgery. Moreover, I-FABP levels were markedly lower at 2 h and 24 h postoperatively in the DEX group than in the Control group (P < 0.001).

CONCLUSIONS

Perioperative DEX administration may potentially confer kidney and intestinal protection during laparoscopic surgery for colorectal cancer patients.

Dexmedetomidine alleviates neuroinflammation, restores sleep disorders and neurobehavioral abnormalities in rats with minimal hepatic encephalopathy

The occurrence and progress of minimal hepatic encephalopathy (MHE) is closely related to the inflammatory response; however, inflammation contributes to behavioral abnormalities and sleep disorders. Dexmedetomidine has anti-inflammatory effects against various diseases. Whether dexmedetomidine improves MHE and the underlying mechanism is yet unclear. The present study aimed to explore the effects of dexmedetomidine on sleep structure, neurobehavior, and brain morphology of MHE rats and investigate its underlying mechanism. A rat MHE model was established by intraperitoneal injection of thioacetamide (TAA). Dexmedetomidine or yohimbine was administered intraperitoneally to investigate the role of α2 adrenoreceptor in the protection conferred by dexmedetomidine. The 24-h sleep, neurobehavioral changes, the liver function, blood ammonia and morphological changes of the liver and brain were assessed. Also, the microglia, astrocytes, neurons, the expression of pro-inflammatory factors (IL-1β, TNF-α, IL-18), and NLRP3 inflammasomes were detected. The results showed that marked sleep disorders, cognitive impairment, anxiety, abnormal liver function and pathological damage of liver and brain were detected in the MHE rats. The microglia in the prefrontal cortex was highly activated along with the increased expression of pro-inflammatory factors and NLRP3 inflammasomes. Interestingly, dexmedetomidine improved above indicators, however, yohimbine significantly abolished the protection of dexmedetomidine. These findings showed that dexmedetomidine restored the changes in the sleep disorders and neurobehavior in rats and reduced brain damage. The mechanism might be partially related to the activation of α2 adrenergic receptors, reduction of neuroinflammatory response, and inhibition of the activation of microglia and NLRP3/Caspase1 signaling pathway.

Dexmedetomidine hydrochloride inhibits hepatocyte apoptosis and inflammation by activating the lncRNA TUG1/miR-194/SIRT1 signaling pathway

Background

Liver injury seriously threatens the health of people. Meanwhile, dexmedetomidine hydrochloride (DEX) can protect against liver injury. However, the mechanism by which Dex mediates the progression of liver injury remains unclear. Thus, this study aimed to investigate the function of DEX in oxygen and glucose deprivation (OGD)-treated hepatocytes and its underlying mechanism.

Methods

In order to investigate the function of DEX in liver injury, WRL-68 cells were treated with OGD. Cell viability was measured by MTT assay. Cell apoptosis was detected by flow cytometry. Inflammatory cytokines levels were measured by ELISA assay. The interaction between miR-194 and TUG1 or SIRT1 was detected by dual-luciferase reporter. Gene and protein levels were measured by qPCR or western blotting.

Results

DEX notably reversed OGD-induced inflammation and apoptosis in WRL-68 cell. Meanwhile, the effect of OGD on TUG1, SIRT1 and miR-194 expression in WRL-68 cells was reversed by DEX treatment. However, TUG1 knockdown or miR-194 overexpression reversed the function of DEX in OGD-treated WRL-68 cells. Moreover, TUG1 could promote the expression of SIRT1 by sponging miR-194. Furthermore, knockdown of TUG1 promoted OGD-induced cell growth inhibition and inflammatory responses, while miR-194 inhibitor or SIRT1 overexpression partially reversed this phenomenon.

Conclusions

DEX could suppress OGD-induced hepatocyte apoptosis and inflammation by mediation of TUG1/miR-194/SIRT1 axis. Therefore, this study might provide a scientific basis for the application of DEX on liver injury treatment.

Dexmedetomidine for prevention of postoperative delirium in older adults undergoing oesophagectomy with total intravenous anaesthesia: A double-blind, randomised clinical trial

BACKGROUND

Dexmedetomidine is known to be a sedative. Recent studies suggest that administration of dexmedetomidine can prevent postoperative delirium (POD) which has been confirmed as a common complication after major surgery. However, its effects in patients undergoing oesophagectomy are scarce.

OBJECTIVE

To investigate the efficacy and safety of dexmedetomidine in reducing POD in elderly patients after transthoracic oesophagectomy with total intravenous anaesthesia (TIVA).

DESIGN

A randomised, double-blind, placebo-controlled trial.

SETTING

Single-centre, tertiary care hospital, November 2016 to September 2018.

PATIENTS

Eligible patients (n = 177) undergoing transthoracic oesophagectomy were randomly assigned to receive total intravenous anaesthesia (TIVA, n = 87) or dexmedetomidine with TIVA (DEX-TIVA, n = 90).

INTERVENTIONS

Patients receiving DEX-TIVA received a loading dose of dexmedetomidine (0.4 μg kg-1), over 15 min, followed by a continuous infusion at a rate of 0.1 μg kg-1 h-1 until 1 h before the end of surgery. Patients receiving TIVA received physiological saline with a similar infusion rate protocol.

OUTCOME MEASURES

The primary outcome was the incidence of POD. The secondary endpoints were the incidence of emergence agitation, serum interleukin-6 (IL-6) levels and haemodynamic profile.

RESULTS

All randomised patients were included with planned intention-to-treat analyses for POD. Delirium occurred in 15 (16.7%) of 90 cases given dexmedetomidine, and in 32 (36.8%) of 87 cases given saline (P = 0.0036). The DEX-TIVA group showed less frequent emergence agitation than the TIVA group (22.1 vs. 48.0%, P = 0.0058). The incremental change in surgery-induced IL-6 levels was greater in the TIVA group than DEX-TIVA group (P < 0.0001).

CONCLUSION

Adding peri-operative dexmedetomidine to a total intravenous anaesthetic safely reduces POD and emergence agitation in elderly patients undergoing open transthoracic oesophagectomy. These benefits were associated with a postoperative reduction in circulating levels of the pro-inflammatory cytokine IL-6 and stabilisation of the haemodynamic profile.

TRIAL REGISTRATION

Chinese Clinical Trials Register Identifier: ChiCTR-IPR-17010881.

Drugs and the liver

The liver is a major organ with multiple functions. A number of drugs are metabolized by the liver during phase 1 and 2 reactions which include complex processes involving cytochrome P450 enzymes. Genetic and acquired variability in cytochrome P450 activity may have profound effects on pharmacokinetics. Additionally, drugs can also modify how the liver functions and cause dysfunction or even failure of the organ both by a direct effect on the liver or by alteration in liver blood flow. It is important to recognize the signs and symptoms of liver failure in patients and identify possible causes including drug interactions. Furthermore, once a patient has been recognized to be suffering with liver dysfunction or failure drug choice and dosing regime will need to be rationalized.

Paracetamol overdose can have severe and life threatening consequences for patients due to its effect on liver function. It is the leading cause of acute liver failure in the UK,¹ Correct and early management is crucial and will be discussed within this article.

Study design of the DAS-OLT trial: a randomized controlled trial to evaluate the impact of dexmedetomidine on early allograft dysfunction following liver transplantation

Background

Perioperative ischemia/reperfusion (I/R) injury during liver transplantation is strongly associated with early allograft dysfunction (EAD), graft loss, and mortality. Hepatic I/R injury also causes remote damage to other organs including the renal and pulmonary systems. Dexmedetomidine (DEX), a selective α2-adrenoceptor agonist which is used as an adjuvant to general anesthesia, has been shown in preclinical studies to provide organ protection by ameliorating the effects of I/R injury in a range of tissues (including the liver). However, prospective clinical evidence of any potential benefits in improving outcomes in liver transplantation is lacking. This study aimed to verify the hypothesis that the application of dexmedetomidine during the perioperative period of liver transplantation can reduce the incidence of EAD and primary graft non-function (PNF). At the same time, the effects of dexmedetomidine application on perioperative renal function and lung function were studied.

Methods

This is a prospective, single-center, randomized, parallel-group study. Two hundred participants (18–65 years) scheduled to undergo liver transplantation under general anesthesia will be included in this study. For participants in the treatment group, a loading dose of DEX will be given after induction of anesthesia (1 μg/kg over 10 min) followed by a continuous infusion (0.5 μg/kg /h) until the end of surgery. For participants in the placebo group, an equal volume loading dose of 0.9% saline will be given after the induction of anesthesia followed by an equal volume continuous infusion until the end of surgery. All other supplements, e.g., opioids, sedatives, and muscle relaxant, will be identical in both arms and administered according to routine clinical practice.

Discussion

The present trial will examine whether DEX confers organoprotective effects in the liver, in terms of reducing the incidence of EAD and PNF in orthotopic liver transplantation recipients.

Trial registration

ClinicalTrials.gov NCT03770130. Registered on 10 December 2018. https://clinicaltrials.gov/ct2/show/NCT03770130

Organ-Protective Effects and the Underlying Mechanism of Dexmedetomidine

Dexmedetomidine (DEX) is a highly selective α2 adrenergic receptor (α2AR) agonist currently used in clinical settings. Because DEX has dose-dependent advantages of sedation, analgesia, antianxiety, inhibition of sympathetic nervous system activity, cardiovascular stabilization, and significant reduction of postoperative delirium and agitation, but does not produce respiratory depression and agitation, it is widely used in clinical anesthesia and ICU departments. In recent years, much clinical study and basic research has confirmed that DEX has a protective effect on a variety of organs, including the nervous system, heart, lungs, kidneys, liver, and small intestine. It acts by reducing the inflammatory response in these organs, activating antiapoptotic signaling pathways which protect cells from damage. Therefore, based on wide clinical application and safety, DEX may become a promising clinical multiorgan protection drug in the future. In this article, we review the physiological effects related to organ protection in α2AR agonists along with the organ-protective effects and mechanisms of DEX to understand their combined application value.

Randomized clinical trial of intraoperative dexmedetomidine to prevent delirium in the elderly undergoing major non-cardiac surgery

Background

Delirium is common in elderly patients after surgery and is associated with poor outcomes. This study aimed to investigate the impact of intraoperative dexmedetomidine on the incidence of delirium in elderly patients undergoing major surgery.

Methods

This was a randomized double-blind placebo-controlled trial. Elderly patients (aged 60 years or more) scheduled to undergo major non-cardiac surgery were randomized into two groups. Patients in the intervention group received a loading dose of dexmedetomidine 0·6 μg/kg 10 min before induction of anaesthesia followed by a continuous infusion (0·5 μg per kg per h) until 1 h before the end of surgery. Patients in the control group received volume-matched normal saline in the same schedule. The primary outcome was the incidence of delirium during the first 5 days after surgery. Delirium was assessed with the Confusion Assessment Method (CAM) for non-ventilated patients and CAM for the Intensive Care Unit for ventilated patients.

Results

In total, 309 patients who received dexmedetomidine and 310 control patients were included in the intention-to-treat analysis. The incidence of delirium within 5 days of surgery was lower with dexmedetomidine treatment: 5·5 per cent (17 of 309) versus 10·3 per cent (32 of 310) in the control group (relative risk (RR) 0·53, 95 per cent c.i. 0·30 to 0·94; P = 0·026). The overall incidence of complications at 30 days was also lower after dexmedetomidine (19·4 per cent (60 of 309) versus 26·1 per cent (81 of 310) for controls; RR 0·74, 0·55 to 0·99, P = 0·047).

Conclusion

Intraoperative dexmedetomidine halved the risk of delirium in the elderly after major non-cardiac surgery. Registration number: ChiCTR-IPR-15007654 (www.chictr.org.cn).

Effect of Remote Ischemic Preconditioning in Patients Undergoing Hepatectomy With Portal Triad Clamping: A Randomized Controlled Trial

BACKGROUND

Remote ischemic preconditioning (RIPC) is reported to reduce liver injury in patients undergoing hepatectomy for colorectal liver metastasis, but its role is unclear in hepatocellular carcinoma patients with portal triad clamping during hepatectomy.

METHODS

In this prospective, randomized trial, 140 patients with hepatocellular carcinoma undergoing liver resection requiring portal triad clamping were randomized to a RIPC group or a control group. Patients in the RIPC group received RIPC (3 cycles of 5-minute ischemia and 5-minute reperfusion in right upper limb with cuff pressure at 30 kPa [225 mm Hg]) approximately 10 minutes after induction of anesthesia. In the control group, patients received sham RIPC (the cuff was not inflated). The primary outcome was the postoperative peak level of total bilirubin (TBIL) and was analyzed with the independent t test. Secondary outcomes were liver function test at postoperative days 1, 3, and 5; postoperative morbidity and mortality during the first month; and the length of postoperative hospital stay.

RESULTS

Data from 136 patients (69 in the RIPC group and 67 in the control group) were analyzed. The RIPC group had on average a 5.9 μmol lower peak level of TBIL than the control group; the mean difference is -5.9, and the 95% confidence interval (CI) reverses to -17.9 to 6.1. There were no significant differences between the 2 groups in liver function test at postoperative days 1, 3, and 5; postoperative morbidity and mortality during the first month; and the length of postoperative hospital stay.

CONCLUSIONS

We found no evidence that RIPC can reduce postoperative liver injury after hepatectomy.

Dexmedetomidine exerts a protective effect on ischemia-reperfusion injury after hepatectomy: A prospective, randomized, controlled study

STUDY OBJECTIVE

Dexmedetomidine, a highly selective α₂-receptor agonist, has been widely used for protection against ischemia-reperfusion (IR) injury. We hypothesized that dexmedetomidine might exert a protective effect on IR injury after hepatectomy.

DESIGN

A prospective, randomized, single-blind study was conducted in 58 patients undergoing hepatectomy who were randomly assigned to two study groups. The dexmedetomidine group (D group) received a loading dose of 0.5 μg/kg for 10 min, and maintained it with 0.5 μg/kg/h until resection of the liver lobes. The control group (C group), received 0.9% sodium chloride administered in the same volume and infusion rate as D group. Eleven patients had hepatic inflow occlusion in D group as did 14 patients in C group.

MEASUREMENTS

The primary outcome was the serum concentration of α-glutathione S-transferase (α-GST), which reflects hepatic ischemic injury. Secondary outcomes included laboratory variables reflecting inflammatory responses, liver and kidney function, and blood coagulation, as well as hemodynamic changes, recovery variables, and complications related to anesthesia and surgery.

RESULTS

The concentration of α-GST at 0.5 h after resection was significantly lower in the dexmedetomidine group than the control group (9.1 ± 3.4 ng/mL vs 15.8 ± 6.5 ng/mL; p < .01), and was also significantly lower in the dexmedetomidine group in subgroup analyses of patients with and without hepatic inflow occlusion. While the concentrations of α-GST at 0.5 h after resection in patients with or without occlusion in D group were comparable, in C group the α-GST concentration without occlusion was significantly higher than that with occlusion. There was an interaction between dexmedetomidine and no occlusion (p < .01), and its concentration in D group without occlusion was the lowest of all subgroups. In addition, there were significant differences in interleukin (IL)-6 and tumor necrosis (TNF)-α concentrations at 24 h after hepatectomy between the two groups, and mean arterial pressure, heart rate, and the bispectral index were also significantly lower in D group than in C group (p < .05). There were significant differences between the two groups in ALT and AST at 2 h and 24 h after the resection of the liver lobe. However, there were no significant differences in renal function, recovery variables, blood coagulation. No severe complications related surgeries and anesthesia were found in both groups.

CONCLUSION

Dexmedetomidine exerts a protective effect on ischemia-reperfusion injury after hepatectomy.

Dexmedetomidine activates the PI3K/Akt pathway to inhibit hepatocyte apoptosis in rats with obstructive jaundice

Obstructive jaundice (OJ) is a common disease in clinical surgery. The present study aimed to determine the effects of dexmedetomidine (Dex) on hepatocyte apoptosis in rats with OJ and also to explore the underlying mechanism. A total of 30 adult male Sprague Dawley rats were randomly divided into 3 groups: Sham group, bile duct ligation (BDL) group, and BDL+Dex group. The serum liver function index, expression levels of serum inflammatory factor interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α), and the liver pathological changes were compared amongst groups. The serum liver function index and expression levels of inflammatory factors in the BDL group and BDL+Dex group were higher compared with the sham group. The serum liver function index and expression levels of inflammatory factors were lower in the BDL+Dex group compared with the BDL group. The severity of hepatic injury was diminished in the BDL+Dex group compared with the BDL group. Compared with the sham group, the hepatocyte apoptosis rate increased significantly in the BDL group and BDL+Dex group. The present findings suggested that Dex improved the liver function of rats with OJ, reduced the production of inflammatory factors and inhibited the apoptosis of hepatocytes. Dex demonstrated a protective effect on liver damage potentially via activation of the phosphoinositide 3-kinase/protein kinase B signaling pathway.

Hepatic Protective Effect of Dexmedetomidine after Partial Hepatectomy Surgery: A Prospective Controlled Study

Background:

Inflow occlusion of the portal triad is a common blood loss-reducing method during hepatectomy which may induce ischemic-reperfusion injury of the remaining parts of the liver. Dexmedetomidine is used for reducing ischemic-reperfusion injury in hepatectomy.

Aim:

The aim of this study was to assess the protective effect of dexmedetomidine on liver after partial hepatectomy using inflow occlusion.

Setting and Design:

This prospective controlled, double-blinded, randomized study included any patients of either sex with age between 20 and 70 years, those in physical status American Society of Anesthesiologists Classes I and II, and those who were planned for partial hepatectomy.

Patients and Methods:

Patients with elective hepatectomy were randomized into dexmedetomidine group, which received dexmedetomidine at 0.3 mg/kg/h, and control group, which received a placebo.

Statistical Analysis:

Statistical analysis was performed using IBM SPSS software version 18. Data were tested using Kolmogorov–Smirnov test, independent t-test or Mann–Whitney U-test, and Chi-square or Fisher's exact test. The statistical significance was considered at P < 0.05.

Results:

Serum albumin, aspartate aminotransferase, alanine aminotransferase, prothrombin time were higher in control group in comparison to dexmedetomidine group. Hypotension duration was lower in control group in comparison to dexmedetomidine group. Vasoconstrictor usage, amount of blood loss, and colloid, crystalloid, and blood given to patients were higher in control group in comparison to the study group.

Conclusions:

Dexmedetomidine can protect the liver during hepatic resection surgery with inflow occlusion with decreasing blood loss and need for blood transfusion.

Comparison of dexmedetomidine vs. remifentanil combined with sevoflurane during radiofrequency ablation of hepatocellular carcinoma: a randomized controlled trial

BACKGROUND

Remifentanil is widely used for ultrasound-guided percutaneous radiofrequency ablation (RFA) of small hepatocellular carcinoma (HCC). We determined whether dexmedetomidine could be an alternative to remifentanil for RFA of HCC under general anesthesia with sevoflurane.

METHODS

We prospectively randomized patients scheduled to undergo RFA for HCC to a dexmedetomidine (DEX) group or remifentanil (REMI) group (47 patients each). In the DEX group, a bolus infusion (0.4 μg kg^- 1) was started 15 min before anesthesia induction and continued at 0.2 μg kg^- 1 h^- 1 until 10 min before the end of surgery. In the REMI group, 3 μg kg^- 1 h^- 1 of remifentanil was administered from 15 min before anesthesia induction to the end of the surgery. The primary endpoint was postoperative pain intensity. Secondary endpoints included analgesic requirement, postoperative liver function, patient comfort, and hemodynamic changes. Group allocation was concealed from patients and data analysts but not from anesthesiologists.

RESULTS

Postoperative pain intensity, analgesic consumption, comfort, liver function, and time to emergence and extubation did not differ between the two groups. Heart rate, but not mean arterial pressure, was significantly lower in the DEX group than in the REMI group, at 1 min after intubation and from 30 min after the start of the surgery until anesthesia recovery. Sevoflurane concentration and dosage were significantly lower in the DEX group than in the REMI group.

CONCLUSION

During RFA for HCC, low-dose dexmedetomidine reduced the heart rate and need for inhalational anesthetics, without exacerbating postoperative discomfort or liver dysfunction. Although it did not exhibit outstanding advantages over remifentanil in terms of pain management, dexmedetomidine could be a safe alternative adjuvant for RFA under sevoflurane anesthesia.

TRIAL REGISTRATION

Chinese Clinical Trial Registry, ChiCTR-OPC-15006613 . Registered on 16 June 2015.

Dexmedetomidine Attenuates Orthotopic Liver Transplantation-Induced Acute Gut Injury via α 2-Adrenergic Receptor-Dependent Suppression of Oxidative Stress

Patients with orthotopic liver transplantation (OLT) frequently develop acute gut injury (AGI), and dexmedetomidine (Dex) has been reported to exert a protective effect against AGI. We investigated whether Dex protects against AGI through antioxidative stress effects by the Nrf2/HO-1 antioxidative signaling pathway. Rats were randomly allocated into a sham group and six orthotopic autologous liver transplantation (OALT) groups receiving different doses of Dex together with/without α ₂-adrenergic receptor (AR) blockers. Intestinal tissues were collected to visualize the barrier damage and to measure the indexes of oxidative stress. For in vitro studies, rat intestinal recess epithelial cells (IEC-6) underwent hypoxia/reoxygenation (H/R), and the protective role of Dex was evaluated after α _2A-AR siRNA silencing. OALT resulted in increased oxidative stress, significant intestinal injury, and barrier dysfunction. Dex attenuated OALT-induced oxidative stress and intestinal injury, which was abolished by the pretreatment with the nonspecific α _2A-AR siRNA blocker atipamezole and the specific α _2A-AR siRNA blocker BRL-44408, but not by the specific _2B/C-AR siRNA blocker ARC239. Silencing of α _2A-AR siRNA also attenuated the protective role of Dex on alleviating oxidative stress in IEC-6 cells subjected to H/R. Dex exerted its protective effects by activating Nrf2/HO-1 antioxidative signaling. Collectively, Dex attenuates OALT-induced AGI via α _2A-AR-dependent suppression of oxidative stress, which might be a novel potential therapeutic target for OALT-induced AGI.

Dexmedetomidine attenuates spinal cord ischemia-reperfusion injury through both anti-inflammation and anti-apoptosis mechanisms in rabbits

Background

Dexmedetomidine (Dex) can improve neuronal viability and protect the spinal cord from ischemia–reperfusion (I/R) injury, but the underlying mechanisms are not fully understood. This study investigated the effects of dexmedetomidine on the toll-like receptor 4 (TLR4)-mediated nuclear factor κB (NF-κB) inflammatory system and caspase-3 dependent apoptosis induced by spinal cord ischemia–reperfusion injury.

Methods

Twenty-four rabbits were divided into three groups: I/R, Dex (10 µg/kg/h prior to ischemia until reperfusion), and Sham. Abdominal aortic occlusion was carried out for 30 min in the I/R and Dex groups. Hindlimb motor function was assessed using the Tarlov scoring system for gait evaluation. Motor neuron survival and apoptosis in the ventral grey matter were assessed by haematoxylin–eosin staining and terminal deoxynucleotidyl transferase-mediated dUTP biotin nick end labelling staining. The expression and localisation of ionised calcium-binding adaptor molecule 1, TLR4, NF-κB and caspase-3 were assessed by immunoreactivity analysis. The levels of interleukin 1β and tumour necrosis factor α were assessed using enzyme-linked immunosorbent assays.

Results

Perioperative treatment with dexmedetomidine was associated with a significant preservation of locomotor function following spinal cord ischemia–reperfusion injury with increased neuronal survival in the spinal cord compared to control. In addition, dexmedetomidine suppressed microglial activation, inhibited the TLR4-mediated NF-κB signalling pathway, and inhibited the caspase-3 dependent apoptosis.

Conclusions

Dexmedetomidine confers neuroprotection against spinal cord ischemia–reperfusion injury through suppression of spinal cord inflammation and neuronal apoptosis. A reduction in microglial activation and inhibition of both the TLR4-mediated NF-κB signalling pathway and caspase-3 dependent apoptosis are implicated.

Locomotor activity of rats with SCI is improved by dexmedetomidine by targeting the expression of inflammatory factors

Dexmedetomidine, a well‑known selective α‑2 adrenoceptor agonist, inhibits the apoptosis of neurons and protects other organs from oxidative damage. In the present study, the effect of dexmedetomidine on spinal cord injury (SCI) in a rat model was investigated. The SCI rat model was prepared using the weight‑drop method, and the effect of dexmedetomidine on locomotor activity was analyzed using the Basso, Beattie and Bresnahan (BBB) rating scale. Western blot analysis was used to observe changes in the expression of apoptosis‑related proteins, including B‑cell lymphoma 2 (Bcl‑2) and Bcl‑2‑associated X protein (Bax). The results revealed that treatment of the SCI rats with dexmedetomidine at a dose of 50 mg/kg significantly prevented the formation of edema in the tissues of the spinal cord. Dexmedetomidine also inhibited the SCI‑induced accumulation of neutrophils in the spinal cord. The BBB scores were significantly increased (P<0.05) in the rats with SCI treated with dexmedetomidine after 10 days. The results of grid walking test revealed a marked decrease in the number of missteps following 10 days of dexmedetomidine treatment. The expression levels of tumor necrosis factor (TNF)‑α and interleukin (IL)‑1β were significantly reduced (P<0.05) in the spinal cord tissues of the dexmedetomidine group, compared with those in the control group of rats. Dexmedetomidine treatment following SCI exerted an inhibitory effect on the SCI‑induced increase in the expression of Bax. The expression of Bcl‑2 was increased in the dexmedetomidine treated rats, compared with that in the control group. Taken together, dexmedetomidine improved the locomotor activity of the rats through the inhibition of edema, reduction in the expression levels of TNF‑α and IL‑1β, and inhibition of the induction of apoptosis. Therefore, dexmedetomidine may be of therapeutic importance for patients with SCI.

The Opioid-Sparing Effect of Perioperative Dexmedetomidine Combined with Oxycodone Infusion during Open Hepatectomy: A Randomized Controlled Trial

Background: A large right subcostal incision performed by open hepatectomy is associated with significant post-operative pain and distress. However, post-operative analgesia solutions still need to be devised. We investigated the effects of intra- and post-operative infusion of dexmedetomidine (Dex) combined with oxycodone during open hepatectomy.

Methods: In this prospective, randomized and double-blind investigation, 52 patients undergoing selective open hepatectomy were divided into Dex group (DEX infusion at an initial loading dose of 0.5 μg⋅kg^-1 over 10 min before intubation then adjusted to a maintenance dose of 0.3 μg⋅kg^-1⋅h^-1 until incision suturing) or control (Con) group (0.9% sodium chloride was administered). Patient-controlled analgesia was administered for 48 h after surgery (Dex group: 60 mg oxycodone and 360 μg DEX diluted to 120 ml and administered at a bolus dose of 2 ml, with 5 min lockout interval and a 1 h limit of 20 ml. Con group: 60 mg oxycodone alone with the same regimen). The primary outcome was post-operative oxycodone consumption. The secondary outcomes included requirement of narcotic and vasoactive drugs, hemodynamics, incidence of adverse effects, satisfaction, first exhaust time, pain intensity, and the Ramsay Sedation Scale.

Results: Post-operative oxycodone consumption was significantly reduced in Dex group from 4 to 48 h after surgery (P < 0.05). Heart rate in Dex group was statistically decreased from T1 (just before intubation) to T6 (20 min after arriving at the post-anesthesia care unit), while mean arterial pressure was significantly decreased from T1 to T3 (during surgical incision; P < 0.05). The consumption of propofol and remifentanil were significantly decreased in Dex group (P < 0.05). The VAS scores at rest at 1, 4, and 8 h and with cough at 24, and 48 h after surgery were lower, the first exhaust time were shorter, satisfaction with pain control was statistically higher and the incidence of nausea and vomiting was less in Dex group than in Con group (all P < 0.05).

Conclusion: The combination of DEX and oxycodone could reduce oxycodone consumption and the incidence of nausea and vomiting, enhance the analgesic effect, improves patient satisfaction and shorten the first exhaust time.

Effects of Dexmedetomidine on Intestinal Microcirculation and Intestinal Epithelial Barrier in Endotoxemic Rats

BACKGROUND

Dexmedetomidine reduces cytokine production in septic patients and reduces inflammation and mortality in experimental models of endotoxemia and sepsis. This study investigated whether dexmedetomidine attenuates endothelial dysfunction, intestinal microcirculatory dysfunction, and intestinal epithelial barrier disruption in endotoxemic rats.

METHODS

Ninety-two male Wistar rats were randomly assigned to the following four groups: (1) Sham; (2) lipopolysaccharide, received IV lipopolysaccharide 15 and 10 mg/kg at 0 and 120 min; (3) dexmedetomidine, received IV dexmedetomidine for 240 min; and (4) lipopolysaccharide + dexmedetomidine, received both lipopolysaccharide and dexmedetomidine. Sidestream dark-field videomicroscope, tissue oxygen monitor, and full-field laser perfusion image were used to investigate the microcirculation of the terminal ileum. Serum endocan level was measured. The Ussing chamber permeability assay, lumen-to-blood gadodiamide passage by magnetic resonance imaging, and bacterial translocation were conducted to determine epithelial barrier function. Mucosal apoptotic levels and tight junctional integrity were also examined.

RESULTS

The density of perfused small vessels in mucosa, serosal muscular layer, and Peyer patch in the lipopolysaccharide + dexmedetomidine group was higher than that of the lipopolysaccharide group. Serum endocan level was lower in the lipopolysaccharide + dexmedetomidine group than in the lipopolysaccharide group. Mucosal ratio of cleaved to full-length occludin and spleen bacterial counts were significantly lower in the lipopolysaccharide + dexmedetomidine group than in the lipopolysaccharide group.

CONCLUSION

The study finding suggests that dexmedetomidine protects against intestinal epithelial barrier disruption in endotoxemic rats by attenuating intestinal microcirculatory dysfunction and reducing mucosal cell death and tight junctional damage. (Anesthesiology 2016; 125:355-67).

Dexmedetomidine-based intravenous anesthesia of a pediatric patient with glucose-6-phosphate dehydrogenase (G6PD) deficiency: A case report

RATIONALE

Glucose-6-phosphate dehydrogenase (G6PD) deficiency is the most common human enzyme defect, resulting in deficits in nicotinamide adenine dinucleotide phosphate production, an important intracellular antioxidant enzyme. G6PD-deficient subjects present with a susceptibility of erythrocytes to oxidative stress and hemolysis, and should avoid drugs or stressors that have oxidative actions. Dexmedetomidine is an anesthetic agent with antioxidant actions.

PATIENT CONCERNS AND DIAGNOSES

A 5-year-old boy with G6PD deficiency. The patient was diagnosed with G6PD deficiency at birth. His red blood cell levels were indicating Class II G6PD activity by the World Health Organization (WHO) classification, but had no history of hemolytic anemia.

INTRAVENTIONS

Because of the patient's anxiety and hyperactivity prior to an operation for upper labial frenum resection, we performed perioperative management using intravenous sedation with dexmedetomidine, which provides upper airway patency and has an antioxidant action.

OUTCOMES

There was no abnormal breathing observed during anesthesia, and arousal was smooth with stable hemodynamics. The patient had no symptoms of hemolytic anemia up to 1 week postsurgery.

CONCLUSION

Antioxidant sedatives such as dexmedetomidine may be useful for reducing the risk of hemolysis after surgery in infant G6PD deficiency cases.

Effect of Dexmedetomidine combined with sufentanil for post- thoracotomy intravenous analgesia:a randomized, controlled clinical study

Background

Few studies have investigated the use of dexmedetomidine in patient-controlled intravenous analgesia (PCIA) after thoracic surgery. This study to evaluate the effect of dexmedetomidine combined with sufentanil for PCIA after thoracotomy under general anaesthesia.

Methods

Ninety-seven adults patients scheduled for thoracotomy surgery. All two groups received PCIA with either sufentanil alone (control group) or combining dexmedetomidine with sufentanil (dexmedetomidine group). Hemodynamic measurements, visual analog scale (VAS) scores at rest and at coughing, Ramsay sedation score (RSS), analgesic consumption, and postoperative nausea and vomiting (PONV) as well as drug-related adverse effects were compared at 2, 6, 12, 24, 36 and 48 h postoperatively.

Results

In the patients of the dexmedetomidine group, compared to the control group, the pain scores at rest or at coughing during 48 h postoperatively were lower (P < 0.001), the sedation scores were lower, the consumption of sufentanil and rescue meperidine were lower, and the number of episode of moderate PONV was three times lower. No signs of toxicity or local complications were observed. There was a non-significant trend for a lower HR and BP in the dexmedetomidine group vs. Control.

Conclusion

The combining dexmedetomidine with sufentanil for post-thoracotomy PCIA can improve pain control together with the decrease in sufentanil requirements, and improve postoperative patient’s satisfaction compared with sufentanil alone in PCIA.

Trial Registration

This trial was retrospectively registered on 27 April 2016 at the Chinese Clinical Trial Register (number: ChiCTR-ONC-16008376).

The Effects of Short-Term Propofol and Dexmedetomidine on Lung Mechanics, Histology, and Biological Markers in Experimental Obesity

BACKGROUND

Administering anesthetics to the obese population requires caution because of a variety of reasons including possible interactions with the inflammatory process observed in obese patients. Propofol and dexmedetomidine have protective effects on pulmonary function and are widely used in short- and long-term sedation, particularly in intensive care unit settings in lean and obese subjects. However, the functional and biological effects of these drugs in obesity require further elucidation. In a model of diet-induced obesity, we compared the short-term effects of dexmedetomidine versus propofol on lung mechanics and histology, as well as biological markers of inflammation and oxidative stress modulation in obesity.

METHODS

Wistar rats (n = 56) were randomly fed a standard diet (lean) or experimental diet (obese) for 12 weeks. After this period, obese animals received sodium thiopental intraperitoneally and were randomly allocated into 4 subgroups: (1) nonventilated (n = 4) for molecular biology analysis only (control); (2) sodium thiopental (n = 8); (3) propofol (n = 8); and (4) dexmedetomidine (n = 8), which received continuous IV administration of the corresponding agents and were mechanically ventilated (tidal volume = 6 mL/kg body weight, fraction of inspired oxygen = 0.4, positive end-expiratory pressure = 3 cm H2O) for 1 hour.

RESULTS

Compared with lean animals, obese rats did not present increased body weight but had higher total body and trunk fat percentages, airway resistance, and interleukin-6 levels in the lung tissue (P = 0.02, P = 0.0027, and P = 0.01, respectively). In obese rats, propofol, but not dexmedetomidine, yielded increased airway resistance, bronchoconstriction index (P = 0.016, P = 0.02, respectively), tumor necrosis factor-α, and interleukin-6 levels, as well as lower levels of nuclear factor-erythroid 2-related factor-2 and glutathione peroxidase (P = 0.001, Bonferroni-corrected t test).

CONCLUSIONS

In this model of diet-induced obesity, a 1-hour propofol infusion yielded increased airway resistance, atelectasis, and lung inflammation, with depletion of antioxidative enzymes. However, unlike sodium thiopental and propofol, short-term infusion of dexmedetomidine had no impact on lung morphofunctional and biological variables.

Effect of perioperative dexmedetomidine on the endocrine modulators of stress response: a meta-analysis

This study examined the effects of perioperative dexmedetomidine treatment on physiological modulators of surgical stress response. The quality of the included studies was assessed prior to performing meta-analyses of the weighted mean differences in the changes from baseline of stress hormones and interpreted in the light of statistical heterogeneity between the studies. Nineteen studies (844 surgical subjects) data were used for this meta-analysis. Dexmedetomidine administration significantly decreased blood cortisol levels (μg/dL) postoperatively (mean difference with 95% confidence interval (CI) from controls: -18.78 (-28.45, -9.10); P < 0.05). In the subgroup analysis, the mean difference between dexmedetomidine-treated and saline-treated subjects in the changes from baseline of the cortisol levels was -20.10 (-30.96, -9.25; P < 0.05) but, between dexmedetomidine- and comparator-treated subjects, it was not statistically significantly different (-15.13 (-49.78, 19.52); P < 0.05). Compared with controls, dexmedetomidine treatment also decreased adrenaline and noradrenaline levels significantly (mean difference in the percent changes from baseline: -90.41 (-145.79, -35.03)%; P < 0.05 and -62.82 (-85.47, -0.40.17)%; P < 0.05, respectively). Dexmedetomidine also decreased prolactin levels with a mean difference of -19.42 (-39.37, 0.52) μg/L (P = 0.06). In conclusion, perioperative use of dexmedetomidine reduces serum catecholamine and cortisol levels but the decrease in cortisol levels was not statistically different from the comparator anaesthetics. More data will be required to assess the effects of dexmedetomidine on corticotropin, prolactin, and growth hormone.

The Influence of Perioperative Dexmedetomidine on Patients Undergoing Cardiac Surgery: A Meta-Analysis

Background

The use of dexmedetomidine may have benefits on the clinical outcomes of cardiac surgery. We conducted a meta-analysis comparing the postoperative complications in patients undergoing cardiac surgery with dexmedetomidine versus other perioperative medications to determine the influence of perioperative dexmedetomidine on cardiac surgery patients.

Methods

Randomized or quasi-randomized controlled trials comparing outcomes in patients who underwent cardiac surgery with dexmedetomidine, another medication, or a placebo were retrieved from EMBASE, PubMed, the Cochrane Library, and Science Citation Index.

Results

A total of 1702 patients in 14 studies met the selection criteria among 1,535 studies that fit the research strategy. Compared to other medications, dexmedetomidine has combined risk ratios of 0.28 (95% confidence interval [CI] 0.15, 0.55, P = 0.0002) for ventricular tachycardia, 0.35 (95% CI 0.20, 0.62, P = 0.0004) for postoperative delirium, 0.76 (95% CI 0.55, 1.06, P = 0.11) for atrial fibrillation, 1.08 (95% CI 0.74, 1.57, P = 0.69) for hypotension, and 2.23 (95% CI 1.36, 3.67, P = 0.001) for bradycardia. In addition, dexmedetomidine may reduce the length of intensive care unit (ICU) and hospital stay.

Conclusions

This meta-analysis revealed that the perioperative use of dexmedetomidine in patients undergoing cardiac surgery can reduce the risk of postoperative ventricular tachycardia and delirium, but may increase the risk of bradycardia. The estimates showed a decreased risk of atrial fibrillation, shorter length of ICU stay and hospitalization, and increased risk of hypotension with dexmedetomidine.

HEPATOPROTECTIVE EFFECT OF DEXMEDETOMIDINE AGAINST RADIOIODINE TOXICITY IN RATS: EVALUATION OF OXIDATIVE STATUS AND HISTOPATHOLOGICAL CHANGES

OBJECTIVE AND BACKGROUND

Based on the anti-inflammatory, antioxidant and anti-apoptotic properties of DEX, the present study was conducted to investigate the possible radioprotective effects of DEX against hepatic radioiodine (I-131) toxicity.

METHODS

Thirty six rats were randomly divided into three groups as untreated control (group 1); oral radioiodine (RAI, 111 MBq) administrated rats (group 2), and DEX group (oral radioiodine and daily intraperitoneal 25 µg/kg DEX administrated rats-group 3). In the third group, DEX administration was started 2 days before and continued for five days after RAI administration. Twenty-four hours after the administration of the last dose of DEX, liver samples were taken for evaluation of oxidative stress parameters and histopathological changes.

RESULTS

The tissue malondialdehyde and advanced oxidation protein product levels in DEX group were significantly lower than RAI group. The total tissue sulphydryl and catalase levels of DEX group were higher than RAI group and the difference was statistically significant. The histopathological damage in the DEX-treated group was significantly less than the damage in the RAI group (p<0.05 for all pathological parameters). Treatment with DEX decreased the histopathological abnormalities when compared with the RAI group.

CONCLUSION

It was presented that DEX had radioprotective effect on the liver after I-131 therapy and anti-inflammatory and antioxidant activities are likely to be involved in the mechanism underlying the radioprotective effects of DEX. After further studies, DEX might be used as a hepatoprotective treatment regimen before administering radioactive iodine therapy particularly in patients with hepatic disease.

Glycyrrhizic acid prevents enteritis through reduction of NF‑κB p65 and p38MAPK expression in rat

Glycyrrhizic acid has a variety of biological properties, including a protective function in the liver, and anti‑inflammatory, anti‑ulcer, anti‑anaphylaxis, anti‑oxidant, immunoregulatory, antiviral and anticancer activities. The efficacy of glycyrrhizic acid can be increased when combined with other medicines. In the present study, the potential protective effects of glycyrrhizic acid against enteritis in rats, and its role in regulating anti‑inflammation, anti‑oxidation, angiogenic and apoptotic mechanisms were investigated using enzyme‑linked immunosorbent and bicinchoninic acid assays, and reverse transcription‑quantitative polymerase chain reaction and western blotting analyses. Adult male Sprague‑Dawley rats were injected with 20 mg/kg methotrexate (MTX) to establish enteritis. Additionally, rats with MTX‑induced enteritis were peritoneally injected with 200 mg glycyrrhizic acid for 9 weeks. The current study demonstrated that glycyrrhizic acid could alleviate MTX‑induced increases of tumor necrosis factor‑α, interleukin (IL)‑1β and IL‑6 levels, and raise IL‑10 levels, in rats with enteritis. Treatment with glycyrrhizic acid significantly reduced D‑lactate and intercellular adhesion molecule‑1 gene expression (P<0.01), but did not inhibit diamine oxidase activity in MTX‑induced enteritis. Pretreatment with glycyrrhizic acid significantly suppressed the promotion of p38 mitogen‑activated protein kinase (p38MAPK), nuclear factor‑κB p65 (NF‑κB p65) protein expression, interferon‑γ protein concentration, and caspase‑3 and cycloxygenase‑2 activity in MTX‑induced enteritis (P<0.01). The findings of the current study suggest that glycyrrhizic acid may prevent enteritis by reducing NF‑κB p65 and p38MAPK expression levels, which may inform future therapeutic strategies for the treatment of enteritis.