Recent Advances in the Clinical Value and Potential of Dexmedetomidine

Dexmedetomidine-mediated improvement of perioperative neurocognitive disorders by miR-184-3p-mediated NLRP3

BACKGROUND

Perioperative neurocognitive disorders (PND) is a neurological complication in the perioperative period, which may lead to severe poor prognosis. Dexmedetomidine (Dex) is a commonly used sedative in the perioperative period. However, the effect of intraoperative anesthetic Dex on PND remains complicated and confusing.

METHODS

PND model was established using aged male mice, treated with Dex, and subjected to behavioral tests. The effect of Dex on pyroptosis was assessed by western blot, enzyme-linked immunosorbent assay and immunofluorescence. In addition, the miRNA expression profile of PND mice was identified by small RNA sequencing and performed PCR to detect miRNAs. Finally, the effect of miRNA on mice neuron pyroptosis was verified in vitro.

RESULTS

We found postoperative cognitive was declined in PND mice compared with control group, while preoperative injection of Dex improved short-term working memory and anxious exploration behavior, alleviated the cognitive impairment. Intriguingly, Dex ameliorated hippocampal inflammation and neuron pyroptosis in PND mice as evidenced by the reduced GSDMD, NLRP3, IL-1β and IL-18. The miRNA expression profile of PND mice hippocampus was disordered, including 5 miRNAs up-regulated and 17 miRNAs down-regulated, compared to the sham group. Dysregulated miRNAs were mainly enriched in biological functions related to neuronal development and signaling pathways related to pyroptosis. MiR-184-3p was the key miRNA, overexpression of miR-184-3p blocked the inhibitory effect of Dex on neuron pyroptosis, which was manifested as increased expression of GSDMD and NLRP3, increased inflammatory factors IL-1β and IL-18.

CONCLUSIONS

This study revealed that miR-184-3p may mediate NLRP3 to prevent the alleviating effect of Dex on PND, which provides a new potential way to improve the therapeutic intervention of PND.

Pharmacologic Analgesia for Cesarean Section: An Update in 2024

PURPOSE OF THE REVIEW

With the increasing prevalence of cesarean section globally, the importance of perioperative analgesia for cesarean section is becoming increasingly evident. This article provides an overview and update on the current status of cesarean section worldwide and associated analgesic regimens.

RECENT FINDINGS

Some recent studies unveiled potential association of neuraxial analgesia might be associated with children's autism, pharmacologic analgesia in obstetric will potentially gain some more attention. Various commonly used techniques and medications for analgesia in cesarean section are highlighted. While neuraxial administration of opioid remains the most classic method, the use of multimodal analgesia, particularly integration of nonsteroidal anti-inflammatory drugs, acetaminophen, peripheral nerve blocks has provided additional and better options for patients who are not suitable for intrathecal and neuraxial techniques and those experiencing severe pain postoperatively. Optimal pain management is crucial for achieving better clinical outcomes and optimal recovery, and with the continuous development of medications, more and better pharmacologic regimen will be available in the future.

Haemodynamic effect of dexmedetomidine during paediatric kidney transplantation

BACKGROUND

Dexmedetomidine is increasingly used for its ability to stabilise haemodynamic status during general anaesthesia. However, there is currently no data on paediatric kidney transplant recipients (pKTR). This study investigates the haemodynamic impact of dexmedetomidine administered perioperatively in pKTR.

METHODS

From 2019 to 2023, a retrospective study was conducted at Nantes University Hospital involving all pKTR under 18 years of age. The study compared intraoperative haemodynamic parameters between patients administered dexmedetomidine during kidney transplantation (DEX group) and those who did not receive it (no-DEX group). Mean arterial pressure (MAP) and heart rate (HR) were monitored throughout the duration of anaesthesia and compared. Graft function was assessed based on creatinine levels and glomerular filtration rate (GFR) at specific intervals. The perioperative use of fluids and vasoactive drugs, as well as their administration within 24 h post-surgery, were analysed.

RESULTS

Thirty-eight patients were enrolled, 10 in the DEX group and 28 in the no-DEX group. Intraoperative HR was similar between the groups; however, MAP was higher in the DEX group (mean difference 9, standard deviation (SD, 1-11) mmHg, p = 0.039). No differences were found regarding the use of fluid and vasoactive drug therapy between groups. GFR at 1 month post-transplantation was significantly elevated in the DEX group (p = 0.009).

CONCLUSIONS

pKTR receiving intraoperative dexmedetomidine exhibited higher perioperative MAP compared to those not administered dexmedetomidine. Additionally, the DEX group demonstrated superior graft function at 1 month. The direct impact of dexmedetomidine on immediate postoperative graft function in pTKR warrants further investigation in a prospective multicentre randomised study.

Effects of Dexmedetomidine in Improving Oxygenation and Reducing Pulmonary Shunt in High-Risk Pediatric Patients Undergoing One-Lung Ventilation for Thoracic Surgery: A Double-Blind Randomized Controlled Trial

Background and objectives Pediatric thoracic surgery has unique considerations due to the immaturity of the respiratory system anatomically and physiologically, which presents technical and pharmacological considerations, including the very common technique of one-lung ventilation (OLV), which causes serious complications in children. Therefore, we investigated the effects of dexmedetomidine on oxygenation and pulmonary shunt fraction (Qs/Qt) in high-risk pediatric patients undergoing OLV for thoracic surgery. This randomized controlled trial aimed to investigate dexmedetomidine's effect on the partial pressure of arterial oxygen (PaO2) and pulmonary shunt fraction (Qs/Qt). Methods A total of 63 children underwent thoracic surgery with OLV and were divided into two groups. The dexmedetomidine group (group Dex, n = 32) received dexmedetomidine (0.4 μg/kg/hour), and the placebo group (group placebo, n = 31) received normal saline. Two arterial and central venous blood samples were taken for arterial and venous blood gas analysis at four time points: T1 (10 minutes after mechanical ventilation of total lung ventilation), T2 (10 minutes after OLV), T3 (60 minutes after OLV), and T4 (20 minutes after the end of OLV). At these intervals, the following parameters were measured: PaO2, Qs/Qt, mean arterial pressure (MAP), heart rate (HR), and peak inspiratory pressure (PIP). Results The two groups had no significant differences in FEV1/FVC and baseline pulmonary shunt fraction (Qs/Qt). Dexmedetomidine significantly improved PaO2 compared with placebo during OLV (T2 and T3). There was a significant decrease in Qs/Qt compared with placebo during OLV (T2, T3, and T4). There was a decrease in PIP compared with placebo during OLV (T2 and T3). No statistically significant differences in MAP or HR were observed between the groups. Conclusion Infusion of dexmedetomidine during OLV in high-risk pediatric thoracic surgery reduces shunt and pulmonary shunt fraction Qs/Qt, improves PaO2 and body oxygenation, reduces PIP and pressure load, and maintains hemodynamic stability (MAP, HR).

Comparison of propofol versus dexmedetomidine sedation for awake C-MAC® D-Blade video laryngoscopic nasotracheal intubation in patients with difficult airway: A randomised clinical study

Background and Aims

Awake intubation is the preferred method for securing difficult airways. We compared intravenous (IV) propofol and dexmedetomidine for C-MAC® D-blade-guided anticipated difficult nasotracheal intubation under conscious sedation.

Methods

This randomised study included 60 patients with difficult airway (El-Ganzouri Score 4-9). After adequate airway preparation with IV midazolam 0.03 mg/kg and IV fentanyl 1 µg/kg, in Group P, propofol was infused at 250 µg/kg/min and in Group D, dexmedetomidine was infused at 1 μg/kg over 10 min, then at 0.5 μg/kg/h till a bispectral index (BIS) value 65-70 was achieved. Patients underwent C-MAC® D-blade video laryngoscope-guided nasotracheal intubation. The intubation score was the primary outcome measure. Secondary outcome measures included haemodynamic parameters, intubation time, number of attempts, the incidence of failed awake intubation, glottic view, time to achieve desired BIS, complications, study drug consumption and patient-reported satisfaction with the awake intubation technique. Quantitative variables were compared between groups using unpaired t-test/Welsch test/Mann-Whitney Test. Qualitative variables were correlated using the Chi-square test/Fisher's exact test. A P value of <0.05 was considered statistically significant.

Results

The intubation score was significantly higher in Group D versus Group P (P = 0.007). Patient reaction to intubation, haemodynamic parameters and percentage of glottis opening score were more favourable in Group P. Coughing and vocal cord movement were comparable between the groups (P > 0.05). The time to target BIS was four times longer, and the time to intubate was 6 seconds longer in Group D.

Conclusion

Successful awake C-MAC® D-blade video laryngoscopic intubation can be performed under dexmedetomidine/propofol conscious sedation, with propofol giving a better intubation score.

Dexmedetomidine as a total intravenous anesthetic in pediatric patients undergoing cleft lip and palate surgery: a case series

BACKGROUND

Surgery for pediatric cleft lip and palate repair often utilizes high-dose opioids and inhaled anesthesia, thereby causing postoperative complications such as desaturation and/or severe agitation after anesthesia. These complications are detrimental to the child and medical personnel and cause tremendous psychologic stress to parents. Our aim is to decrease these complications through dexmedetomidine, an alpha-2 receptor agonist with anxiolytic, sympatholytic, and analgetic properties. Devoid of respiratory depressant effect, it allows patients to maintain effective ventilation and reduce agitation, postoperatively. Its unique anesthetic property may shed light on providing safe anesthesia and gentle emergence to this young, vulnerable population.

CASE PRESENTATION

A total of 21 patients of Sundanese ethnicity, aged 3 months to 8 years (9 males and 12 females), underwent cleft lip or cleft palate surgery using total intravenous dexmedetomidine. Anesthesia was induced using sevoflurane, fentanyl, and propofol, and airway was secured. Intravenous dexmedetomidine 1.5 μg/kg was administered within 10 minutes, and a maintenance dose of 1.5 μg/kg/hour was continued as the sole anesthetic maintenance agent thereafter. Hemodynamics and anesthetic depth using Patient State Index (SEDLine™ monitor, Masimo Corporation, Irvine, CA, USA) were monitored carefully throughout the surgical procedure. Dexmedetomidine did not cause any hemodynamic derangements or postoperative complications in any of our patients. We found agitation in 9.5% (2/21) of patients.

CONCLUSION

Dexmedetomidine can be used as a total intravenous anesthetic agent to maintain anesthesia and provide gentle emergence to infants and young children undergoing cleft lip and palate repair.

Clinical adverse events to dexmedetomidine: a real-world drug safety study based on the FAERS database

Objective

Adverse events associated with dexmedetomidine were analyzed using data from the FDA's FAERS database, spanning from 2004 to the third quarter of 2023. This analysis serves as a foundation for monitoring dexmedetomidine's safety in clinical applications.

Methods

Data on adverse events associated with dexmedetomidine were standardized and analyzed to identify clinical adverse events closely linked to its use. This analysis employed various signal quantification analysis algorithms, including Reporting Odds Ratio (ROR), Proportional Reporting Ratio (PRR), Bayesian Confidence Propagation Neural Network (BCPNN), and Multi-Item Gamma Poisson Shrinker (MGPS).

Results

In the FAERS database, dexmedetomidine was identified as the primary suspect in 1,910 adverse events. Our analysis encompassed 26 organ system levels, from which we selected 346 relevant Preferred Terms (PTs) for further examination. Notably, adverse drug reactions such as diabetes insipidus, abnormal transcranial electrical motor evoked potential monitoring, acute motor axonal neuropathy, and trigeminal cardiac reflex were identified. These reactions are not explicitly mentioned in the drug's specification, indicating the emergence of new signals for adverse drug reactions.

Conclusion

Data mining in the FAERS database has elucidated the characteristics of dexmedetomidine-related adverse drug reactions. This analysis enhances our understanding of dexmedetomidine's drug safety, aids in the clinical management of pharmacovigilance studies, and offers valuable insights for refining drug-use protocols.

Role of Dexmedetomidine and Clonidine With Hyperbaric Ropivacaine in Subarachnoid Block: A Comprehensive Review

Subarachnoid block (SAB), a fundamental technique in regional anesthesia, offers efficient anesthesia for various surgical procedures with advantages including rapid onset, reliable anesthesia, and reduced systemic effects compared to general anesthesia. Hyperbaric ropivacaine, a long-acting local anesthetic, has gained popularity due to its favorable pharmacokinetic profile and safety profile. However, to extend the duration and enhance the quality of anesthesia provided by hyperbaric ropivacaine, adjuvants such as dexmedetomidine and clonidine are frequently employed. This comprehensive review explores the roles of dexmedetomidine and clonidine as adjuvants to hyperbaric ropivacaine in SAB. It examines their pharmacological mechanisms, clinical efficacy, safety profiles, and comparative effectiveness in prolonging analgesia and enhancing anesthesia. The review synthesizes evidence from clinical studies to delineate the synergistic effects of these adjuvants, their impact on patient outcomes, and their potential advantages over traditional anesthesia techniques. Through a detailed analysis of current literature and clinical practices, this review aims to provide insights into optimizing the use of dexmedetomidine and clonidine in SAB protocols. It discusses clinical implications, offers recommendations for practice, and identifies future research directions to further enhance the efficacy and safety of SAB using these adjuvants.

An evaluation of dexmedetomidine in combination with midazolam in pediatric sedation: a systematic review and meta-analysis

BACKGROUND

Dexmedetomidine and midazolam are commonly used sedatives in children. We conducted a systematic review and meta-analysis to compare the safety and effectiveness of sedation provided by dexmedetomidine combined with midazolam versus other sedatives including chloral hydrate, midazolam and other sedatives in pediatric sedation.

METHODS

The Embase, Web of Science, Cochrane Library, and PubMed databases, and Clinicaltrials.gov register of controlled trials were searched from inception to June 2022. All randomized controlled trials used dexmedetomidine-midazolam in pediatric sedation were enrolled. The articles search, data extraction, and quality assessment of included studies were performed independently by two researchers. The success rate of sedation was considered as the primary outcome. The secondary outcomes included onset time of sedation, recovery time of sedation and occurrence of adverse events.

RESULTS

A total of 522 studies were screened and 6 RCTs were identified; 859 patients were analyzed. The administration of dexmedetomidine combined with midazolam was associated with a higher sedation success rate and a lower incidence of nausea and vomiting in computed tomography, magnetic resonance imaging, Auditory Brainstem Response test or fiberoptic bronchoscopy examinations than the other sedatives did (OR = 2.92; 95% CI: 1.39-6.13, P = 0.005, I2 = 51%; OR = 0.23, 95% CI: 0.07-0.68, P = 0.008, I2 = 0%, respectively). Two groups did not differ significantly in recovery time and the occurrence of adverse reactions (WMD = - 0.27, 95% CI: - 0.93 to - 0.39, P = 0.42; OR 0.70; 95% CI: 0.48-1.02, P = 0.06, I2 = 45%. respectively). However, the results of the subgroup analysis of ASA I-II children showed a quicker onset time in dexmedetomidine-midazolam group than the other sedatives (WMD=-3.08; 95% CI: -4.66 to - 1.49, P = 0.0001, I2 = 30%).

CONCLUSIONS

This meta-analysis showed that compared with the control group, dexmedetomidine combined with midazolam group provided higher sedation success rates and caused a lower incidence of nausea and vomiting in completing examinations, indicating a prospective outpatient clinical application for procedural sedation.

Determining the Optimal Dosage of Dexmedetomidine for Smooth Emergence in Older Patients Undergoing Spinal Surgery: A Study of 44 Cases

BACKGROUND Emergence agitation, or delirium, occurs during early recovery from general anesthesia and involves disorientation, excitation, and uncontrolled physical movements. Dexmedetomidine is an alpha agonist that has sedative, anxiolytic, analgesic, and sympatholytic activities and is used as a continuous infusion to prevent emergence agitation. This study aimed to evaluate patients aged 65 years and older undergoing general anesthesia to determine the 90% effective dose (ED90) of dexmedetomidine continuous intraoperative infusion to prevent emergence agitation. MATERIAL AND METHODS We enrolled 44 patients aged 65 years and older undergoing spinal surgery under general anesthesia. Dexmedetomidine administration commenced 30 minutes before surgery completion, with a predetermined infusion dose (μg/kg/h), without a loading dose. The initial dose was 0.2 μg/kg/h, and subsequent step size was ±0.05 μg/kg/h. We tried to find ED90 of dexmedetomidine using the biased-coin design. Vital signs, extubation quality scores, extubation-related complications, and postoperative outcomes were monitored. RESULTS Dexmedetomidine ED₉₀ for smooth emergence in older patients was 0.34 μg/kg/h. Peri-extubation vital signs remained within 20% of baseline values, without requiring pharmacological intervention. No hypoxia, hypoventilation, or post-extubation agitation occurred. In the recovery room, 1 patient briefly exhibited excitement but quickly calmed. Nine patients initially unresponsive in the recovery room fully awoke and were promptly discharged. CONCLUSIONS For older patients who are vulnerable to adverse effects of anesthetics and opioids, dexmedetomidine enables gentle awakening without adverse vital sign changes, respiratory depression, excessive sedation, or emergence agitation (ED₉₀=0.34 μg/kg/h). Further studies should involve a larger patient cohort, considering diverse medical conditions in older individuals.

Dexmedetomidine for reducing succinylcholine-induced myalgia in patients undergoing electroconvulsive therapy: A randomised controlled trial

Background and Aim

Electroconvulsive therapy (ECT) is an effective intervention for psychiatric patients. Succinylcholine is considered the drug of choice for muscle relaxation for ECT. Significant adverse effects of succinylcholine include fasciculation and myalgia. Dexmedetomidine is a highly selective α-2 adrenergic agonist. This study aims to determine the efficacy of a low dose of dexmedetomidine in reducing succinylcholine-induced myalgia in patients receiving ECT.

Methods

This randomised controlled trial was conducted on 100 patients, aged 18-65 years, undergoing ECT, who were randomly allocated into two groups with an allocation ratio of 1:1. Group D received intravenous (IV) dexmedetomidine 0.25 µg/kg, and Group C received IV normal saline (0.9%). Patients' self-reported myalgia scores were measured after 60 min of the procedure. Fasciculations were noted after IV succinylcholine administration. Heart rate (HR) and mean blood pressure (MBP) were measured at baseline, after infusion (5 min) and after ECT (0, 2.5, 5, 10, 15, 30 min). Continuous data were analysed using a Student's t-test for two-group comparisons, a mixed model analysis of variance for group comparisons and various time point analyses. Categorical data were analysed using the Chi-square/Fisher's exact test.

Results

There were no differences between the groups regarding demographics. Myalgia and fasciculations were less in Group D than in Group C (P < 0.001). MBP and HR changes were comparable (P > 0.05).

Conclusion

A low dose of dexmedetomidine (0.25 µg/kg) effectively reduces myalgia and fasciculations due to succinylcholine in patients undergoing electroconvulsive therapy.

Effects of Dexmedetomidine on Cognitive Function, Oxidative Stress and Brain Protection in Patients Undergoing Craniocerebral Surgery

BACKGROUND

The protective mechanism of dexmedetomidine on the brains of patients undergoing craniocerebral surgery remains unclear. The aim of this study was to examine the impact of dexmedetomidine on cognitive function, oxidative stress, and brain protection in such patients.

METHODS

Fifty-four patients who underwent craniocerebral surgery at our hospital from January 2020 to June 2023 were retrospectively selected as study subjects. They were divided into two groups: the control group (n = 27) and the study group (n = 27), based on different auxiliary anesthesia protocols. Patients in the study group received dexmedetomidine before anesthesia induction, using a midline intravenous pump to assist anesthesia, while the control group received an equivalent amount of normal saline. The remaining anesthesia induction and maintenance protocols were consistent for both groups. Cognitive function was assessed using the Mini Mental State Examination (MMSE) before and 1 day after surgery for both groups. Oxidative stress indicators, including malondialdehyde (MDA), glutathione peroxidase (GSH-Px), and superoxide dismutase (SOD) levels in the serum of both groups, were measured using enzyme-linked immunosorbent assay (ELISA). Additionally, changes in postoperative brain injury indicators, namely neuron-specific enolase (NSE) and central nervous system-specific protein (S100β), were detected and compared in the serum of both groups. Concurrently, postoperative adverse reactions were recorded for both groups.

RESULTS

The MMSE scale scores of both groups of patients 24 hours after surgery were significantly lower than those before surgery. However, the MMSE scale scores of the study group patients were notably higher than those in the control group, with a statistically significant difference (p < 0.05). One hour after surgery, the serum levels of MDA, GSH-Px, and SOD in both groups of patients were significantly elevated compared to pre-surgery levels. Yet, the study group exhibited significantly lower levels of MDA, GSH-Px, and SOD in comparison to the control group, and these differences were statistically significant (p < 0.05). The serum levels of NSE and S100β in both groups were markedly higher than preoperative levels 24 hours after surgery. However, the study group demonstrated significantly lower levels of serum NSE and S100β compared to the control group, with a statistically significant difference (p < 0.05). The incidence of postoperative complications in the study group was 7.41% (2/27), indicating a decreasing trend compared to 18.52% (5/27) in the control group. However, this difference did not reach statistical significance (χ2 = 1.477, p = 0.224).

CONCLUSION

Dexmedetomidine-assisted anesthesia in craniocerebral surgery can effectively enhance postoperative cognitive function, mitigate oxidative stress, and facilitate overall postoperative recovery for patients. The intervention exhibits a favorable safety profile with no reported serious adverse reactions, establishing it as a relatively safe and reliable approach.

Comparison of the effect of dexmedetomidine intrathecal injection and intravenous infusion on subarachnoid blockade during knee arthroscopy procedures: a randomized controlled trial

BACKGROUND

Comparison of whether intrathecal dexmedetomidine prolongs spinal anesthesia-associated sensorimotor blockade more than intravenous infusion during knee arthroscopy procedures performed under subarachnoid blockade.

METHODS

Ninety patients aged 18-75 years, ASA class I-II, who underwent knee arthroscopy between October 2022 and April 2023 were randomized into intrathecal、intravenous and control groups.Subjects received three modes of administration: an intrathecal group (2 ml of 1% ropivacaine + 1 ml of 5 μg dexmedetomidine, along with intravenous saline infusion), an intravenous group (intrathecal 2 ml of 1% ropivacaine + 1 ml of 0.9% saline, with dexmedetomidine pumped intravenously at a dose of 0.5 μg/kg/h), and a control group (intrathecal 2 ml of 1% ropivacaine + 1 ml of 0.9% saline, along with intravenous saline infusion). Total analgesic duration, duration of sensory and motor blockade, Ramsay sedation score, Visual Analogue Score (VAS) at different postoperative time points, and occurrence of adverse effects were recorded.

RESULTS

The total analgesia duration was significantly longer in the intrathecal group than in the intravenous and control groups (352.13 ± 51.70 min VS 273.47 ± 62.57 min VS 241.41 ± 59.22 min, P < 0.001).The onset of sensory block was shorter in the intrathecal group than in the intravenous and control groups (4 [3-4]min VS 5 [4-5]min VS 5 [4-5]min; P < 0.001);the onset of motor block was shorter in the intrathecal group than in the intravenous group and the control group (5 [4-5]min VS 5 [5-6]min VS 6[5.5-7]min; P < 0.001).Sedation scores were higher in the intravenous group than in the intrathecal and control groups (P < 0.001). At 5 h postoperatively, the VAS score in the intrathecal group was lower than that in the intravenous and control groups (P < 0.001). At 24 h postoperatively, the VAS score in the intrathecal group was lower than that in the control group (P < 0.001). In addition, the incidence of bradycardia was significantly higher in the intravenous group than in the intrathecal and control groups (30%, 6.5%, and 3.4%, respectively; P = 0.018, P = 0.007).

CONCLUSIONS

Intrathecal administration of dexmedetomidine did prolong the total analgesia duration, as well as accelerate the onset of sensory-motor blockade compared with intravenous infusion, and did not result in any hemodynamic instability or other adverse events at the doses studied.

TRIAL REGISTRATION

This single-center, prospective, RCT has completed the registration of the Chinese Clinical Trial Center at 26/09/2023 with the registration number ChiCTR2300076170.

Molecular mechanisms of cholinergic neurotransmission in visceral smooth muscles with a focus on receptor-operated TRPC4 channel and impairment of gastrointestinal motility by general anaesthetics and anxiolytics

Acetylcholine is the primary excitatory neurotransmitter in visceral smooth muscles, wherein it binds to and activates two muscarinic receptors subtypes, M2 and M3, thus causing smooth muscle excitation and contraction. The first part of this review focuses on the types of cells involved in cholinergic neurotransmission and on the molecular mechanisms underlying acetylcholine-induced membrane depolarisation, which is the central event of excitation-contraction coupling causing Ca2+ entry via L-type Ca2+ channels and smooth muscle contraction. Studies of the muscarinic cation current in intestinal myocytes (mICAT) revealed its main molecular counterpart, receptor-operated TRPC4 channel, which is activated in synergy by both M2 and M3 receptors. M3 receptors activation is of permissive nature, while activation of M2 receptors via Gi/o proteins that are coupled to them plays a direct role in TRPC4 opening. Our understanding of signalling pathways underlying mICAT generation has vastly expanded in recent years through studies of TRPC4 gating in native cells and its regulation in heterologous cells. Recent studies using muscarinic receptor knockout have established that at low agonist concentration activation of both M2 receptor and the M2/M3 receptor complex elicits smooth muscle contraction, while at high agonist concentration M3 receptor function becomes dominant. Based on this knowledge, in the second part of this review we discuss the cellular and molecular mechanisms underlying the numerous anticholinergic effects on neuroactive drugs, in particular general anaesthetics and anxiolytics, which can significantly impair gastrointestinal motility. This article is part of the Special Issue on "Ukrainian Neuroscience".

Dexmedetomidine mitigates neuroinflammation in an Alzheimer's disease mouse model via the miR-204-3p/FBXL7 signaling axis

Alzheimer's disease (AD) is a prevalent neurodegenerative disorder characterized by neuroinflammation. Dexmedetomidine (Dex) is known for its neuroprotective properties in clinical settings. In this study, we investigated the potential of Dex in protecting against neuroinflammation in an AD mouse model induced by amyloid-beta (Aβ) injection. First, in the AD mouse model, Aβ injection were administered, and the model was confirmed through behavioral tests, including the Morris water maze and Y-maze. Neuroinflammatory states in Aβ-injected mice were assessed using hematoxylin and eosin staining and enzyme-linked immunosorbent assay. Expression levels of microRNA (miR)-204-3p and F-box/LRR-repeat protein 7 (FBXL7) in mouse tissues were determined through real-time quantitative polymerase chain reaction and Western blot. The binding interaction between miR-204-3p and FBXL7 was elucidated using dual-luciferase analysis. Aβ-injected mice exhibited cognitive impairment, neuroinflammation, and downregulated miR-204-3p. Upregulation of miR-204-3p reduced inflammatory infiltration and mitigated neuroinflammation in Aβ-injected mice. Dex treatment reduced inflammation in hippocampal tissues of Aβ-injected mice. Dex treatment upregulated miR-204-3p, leading to suppressed FBXL7 expression in tissues. Inhibition of miR-204-3p or overexpression of FBXL7 reversed the alleviating effect of Dex on neuroinflammation in Aβ-injected mice. Overall, Dex increased miR-204-3p expression, resulting in the inhibition of FBXL7, and subsequently alleviated neuroinflammation in Aβ-injected mice.

Efficacy of ultrasound guided superior laryngeal nerve block on sedation for delayed extubation in maxillofacial surgery with free flap reconstruction

OBJECTIVE

Superior laryngeal nerve block (SLNB) is a regional anesthesia technique for addressing airway response. However, SLNB on the efficacy of sedation in patients with delayed extubation is unknown, particularly for maxillofacial surgery (MS). The aim of the study was to assess whether ultrasound guided (UG) SLNB reduces the incidence of moderate to severe cough for delayed extubation in MS with free flap reconstruction.

METHODS

60 patients were randomly assigned to the GEA group (control group) and the SLNB group (UG-SLNB postoperatively, study group). During the initial two postoperative hours, the incidence of moderate and severe cough, agitation, and the number of patients requiring rescue propofol and flurbiprofen were recorded. Additionally, the time spent under the target level of sedation, postoperative hemodynamics, and the total does of propofol during the postoperative 24 h were recorded.

RESULTS

The data showed the SLNB group had a significantly lower incidence of moderate to severe cough and agitation (p < 0.05), and a longer sedation time (p < 0.05). The number of patients required rescue propofol and flurbiprofen, as well as the hemodynamic changes, were significantly different between the two groups (p < 0.05).

CONCLUSION

The use of UG-SLNB is associated with reduced incidence of postoperative cough. Moreover, SLNB can enhance the efficacy of postoperative sedation with need of fewer agents postoperatively.

CLINICAL TRIAL REGISTRATION

ChiCTR2000039982.

Efficacy and safety of sedation with dexmedetomidine in adults undergoing gastrointestinal endoscopic procedures: systematic review and meta-analysis of randomized controlled trials

Background: The sedative role of dexmedetomidine (DEX) in gastrointestinal endoscopic procedures is unclear. We performed this systematic review and meta-analysis to assess the efficacy and safety of sedation with DEX during gastrointestinal endoscopic procedures with a view to providing evidence-based references for clinical decision-making. Methods: The PubMed, Embase, Cochrane Library, Web of Science, and ClinicalTrials.gov databases were searched for randomized controlled trials (RCTs) that compared DEX with different sedatives comparators (such as propofol, midazolam, and ketamine) for sedation in a variety of adult gastrointestinal endoscopic procedures from inception to 1 July 2022. Standardized mean difference (SMD) and weighted mean difference (WMD) with 95% confidence interval (CI) or pooled risk ratios (RR) with 95% CI were used for continuous outcomes or dichotomous outcomes, respectively, and a random-effect model was selected regardless of the significance of the heterogeneity. Results: Forty studies with 2,955 patients were assessed, of which 1,333 patients were in the DEX group and 1,622 patients were in the control (without DEX) group. The results suggested that the primary outcomes of sedation level of DEX are comparable to other sedatives, with similar RSS score and patient satisfaction level, and better in some clinical outcomes, with a reduced risk of body movements or gagging (RR: 0.60; 95% CI: 0.37 to 0.97; p = 0.04; I2 = 68%), and a reduced additional requirement for other sedatives, and increased endoscopist satisfaction level (SMD: 0.41; 95% CI: 0.05 to 0.77; p = 0.03; I2 = 86%). In terms of secondary outcomes of adverse events, DEX may benefit patients in some clinical outcomes, with a reduced risk of hypoxia (RR:0.34; 95% CI: 0.20 to 0.55; p < 0.0001; I2 = 52%) and cough (RR: 0.25; 95% CI: 0.12 to 0.54; p = 0.0004; I2 = 0%), no significant difference in the risk of hypotension, while an increased risk of bradycardia (RR: 3.08; 95% CI: 2.12 to 4.48; p < 0.00001; I2 = 6%). Conclusion: This meta-analysis indicates that DEX is a safe and effective sedative agent for gastrointestinal endoscopy because of its benefits for patients in some clinical outcomes. Remarkably, DEX is comparable to midazolam and propofol in terms of sedation level. In conclusion, DEX provides an additional option in sedation for gastrointestinal endoscopic procedures. Systematic Review Registration: https://www.crd.york.ac.uk/PROSPERO/#searchadvanced.

Dexmedetomidine combined with propofol attenuates myocardial ischemia/reperfusion injury by activating the AMPK signaling pathway

Objective

Myocardial ischemia/reperfusion (MI/R) injury is a major cause of cardiac tissue damage, with high disability and death rates. Although both dexmedetomidine (Dex) and propofol (PPF) have been indicated to alleviate MI/R injury in rat models, the effects of the combined use of these two drugs remain unclear. This study aimed to investigate the combined effects of Dex and PPF against MI/R injury and related mechanisms.

Methods

A rat model of MI/R injury was established and used to explore the combined effects of Dex and PPF on MI/R injury. Hematoxylin-eosin (HE) and Masson staining were used for histopathological evaluation. 2,3,5-triphenyltetrazolium chloride (TTC), echocardiography, terminal deoxynucleotidyl transferase dUTP nick-end labeling (TUNEL) staining were used to determine myocardial infarction size, cardiac function, and apoptosis, respectively. Enzyme-linked immunosorbent assay (ELISA) was performed to assess myocardial function and oxidative stress (OS). Autophagy was observed through transmission electron microscopy. Moreover, western blotting was conducted to detect autophagy markers and the AMPK pathway.

Results

The combination of Dex and PPF alleviated histopathological injury, reduced myocardial infarction, and rescued cardiac dysfunction in MI/R rats. Furthermore, Dex combined with PPF decreased the levels of MDA and ROS and increased the SOD level in MI/R rats. Besides, Dex combined with PPF inhibited myocardial apoptosis in MI/R rats. After combined treatment with Dex and PPF, the number of autophagosomes, expression levels of Beclin-1 and LC3II/LC3I were elevated, while the expression levels of p62 were reduced in MI/R rats. The combined use of Dex and PPF activated the AMPK pathway in MI/R rats. Compound C (an AMPK inhibitor) could abolish the combined effects of Dex and PPF on alleviating myocardial injury and enhancing autophagy in MI/R rats.

Conclusion

The combination of Dex and PPF attenuated MI/R injury in rats, which may be associated with the activation of the AMPK signaling pathway.

Development and validation of a nomogram for predicting intraoperative hypotension in cardiac valve replacement

Background: Cardiac valve replacement risks include intraoperative hypotension, endangering organ perfusion. Our nomogram predicted hypotension risk in valve surgery, guiding early intervention. Methods: Analyzing 561 patients from July to November 2022, we developed a nomogram to predict hypotension in valve replacement patients, validated using data from December 2022 to January 2023 on 241 patients, with robust statistical confirmation. Results: Our study identified age, hypertension, left ventricular ejection fraction and serum creatinine as hypotension predictors. The resulting nomogram, validated with high concordance index and area under the curve scores, provided a clinically useful tool for managing intraoperative risk. Conclusion: For valve replacement patients, factors like age, hypertension, low left ventricular ejection fraction and high serum creatinine predicted hypotension risk. Our nomogram enabled clinicians to quantify this risk and proactively manage it.

Genetic polymorphisms are associated with individual susceptibility to dexmedetomidine

Introduction: Dexmedetomidine (DXM) is widely used as an adjuvant to anesthesia or a sedative medicine, and differences in individual sensitivity to the drug exist. This study aimed to investigate the effect of genetic polymorphisms on these differences. Methods: A total of 112 patients undergoing hand surgery were recruited. DXM 0.5 μg/kg was administered within 10 min and then continuously injected (0.4 μg/kg/h). Narcotrend index, effective dose and onset time of sedation, MAP, and HR were measured. Forty-five single nucleotide polymorphisms (SNPs) were selected for genotype. Results: We observed individual differences in the sedation and hemodynamics induced by DXM. ABCG2 rs2231142, CYP2D6 rs16947, WBP2NL rs5758550, KATP rs141294036, KCNMB1 rs11739136, KCNMA1 rs16934182, ABCC9 rs11046209, ADRA2A rs1800544, and ADRB2 rs1042713 were shown to cause statistically significant (p < 0.05) influence on the individual variation of DXM on sedation and hemodynamics. Moreover, the multiple linear regression analysis indicated sex, BMI, and ADRA2A rs1800544 are statistically related to the effective dose of DXM sedation. Discussion: The evidence suggests that the nine SNPs involved in transport proteins, metabolic enzymes, and target proteins of DXM could explain the individual variability in the sedative and hemodynamic effects of DXM. Therefore, with SNP genotyping, these results could guide personalized medication and promote clinical and surgical management.

Dexmedetomidine ameliorates diabetic cardiomyopathy by inhibiting ferroptosis through the Nrf2/GPX4 pathway

OBJECTIVE

Dexmedetomidine (DEX) has been shown to have anti-apoptotic effects in diabetes mellitus, but its role in mitigating diabetic cardiomyopathy (DCM) through ferroptosis regulation is unclear.

METHODS

An in vitro DCM model was established using H9C2 cells induced with high glucose (HG) and treated with DEX at varying doses and a nuclear factor erythroid 2-realated factor 2 (Nrf2) specific inhibitor ML385. Cell viability was evaluated using the MTT method after treatment with DEX or mannitol (MAN), and the dosage of DEX used in subsequent experimentation was determined. The effects of HG-induced high osmotic pressure were assessed using MAN as a control. Cell apoptosis was evaluated using flow cytometry. Protein levels of Bcl2, Bax, nuclear Nrf2, and glutathione peroxidase 4 (GPX4) were measured using Western blot. Superoxide dismutase (SOD) activity, malondialdehyde (MDA) levels, Fe²⁺ concentration and reactive oxygen species (ROS) levels were measured using corresponding kits and dichlorodihydrofluorescein diacetate, respectively.

RESULTS

Treatment with DEX or MAN had no effect on H9C2 cell viability. HG induction reduced H9C2 cell viability, increased cell apoptosis, upregulated levels of Bax, Fe²⁺, MDA, and ROS, and downregulated Bcl2 protein levels, SOD activity, and protein levels of nuclear Nrf2 and GPX4. DEX inhibited HG-induced H9C2 cell apoptosis, promoted Nrf2 nuclear translocation, and activated the Nrf2/GPX4 pathway. Inhibition of Nrf2 partially reversed the protective effects of DEX against HG-evoked H9C2 cell injury.

CONCLUSION

Our findings demonstrate that DEX attenuates HG-induced cardiomyocyte injury by inhibiting ferroptosis through the Nrf2/GPX4 pathway, providing potential therapeutic targets for DCM treatment.

Alpha2 Adrenergic Modulation of Spike-Wave Epilepsy: Experimental Study of Pro-Epileptic and Sedative Effects of Dexmedetomidine

In the present report, we evaluated adrenergic mechanisms of generalized spike-wave epileptic discharges (SWDs), which are the encephalographic hallmarks of idiopathic generalized epilepsies. SWDs link to a hyper-synchronization in the thalamocortical neuronal activity. We unclosed some alpha2-adrenergic mechanisms of sedation and provocation of SWDs in rats with spontaneous spike-wave epilepsy (WAG/Rij and Wistar) and in control non-epileptic rats (NEW) of both sexes. Dexmedetomidine (Dex) was a highly selective alpha-2 agonist (0.003-0.049 mg/kg, i.p.). Injections of Dex did not elicit de novo SWDs in non-epileptic rats. Dex can be used to disclose the latent form of spike-wave epilepsy. Subjects with long-lasting SWDs at baseline were at high risk of absence status after activation of alpha2- adrenergic receptors. We create the concept of alpha1- and alpha2-ARs regulation of SWDs via modulation of thalamocortical network activity. Dex induced the specific abnormal state favorable for SWDs-"alpha2 wakefulness". Dex is regularly used in clinical practice. EEG examination in patients using low doses of Dex might help to diagnose the latent forms of absence epilepsy (or pathology of cortico-thalamo-cortical circuitry).

RNA-sequencing approach for exploring the protective mechanisms of dexmedetomidine on pancreatic injury in severe acute pancreatitis

Background: Severe acute pancreatitis (SAP) is a severe form of acute pancreatitis with the potential to cause life-threatening complications. Patients with acute SAP require surgical intervention and are admitted to the intensive care unit for non-invasive ventilation. Dexmedetomidine (Dex) is currently used by intensive care clinicians and anaesthesiologists as an adjunctive sedative. Therefore, the clinical availability of Dex makes it easier to implement in SAP treatment than developing new drugs. Methods: Randomly dividing thirty rats into sham-operated (Sham), SAP, and Dex groups. The severity of pancreatic tissue injury in each rat was assessed by Hematoxylin and eosin (HE) staining. Serum amylase activity and inflammatory factor levels were measured using commercially available kits. The expressions of necroptosis-related proteins, myeloperoxidase (MPO), CD68, and 4-hydroxy-trans-2-nonenal (HNE) were detected using immunohistochemistry (IHC). Transferase-mediated dUTP nick-end labeling (TUNEL) staining was utilized to identify pancreatic acinar cell apoptosis. The subcellular organelle structure of pancreatic acinar cells was observed using transmission electron microscopy. The regulatory effect of Dex on the gene expression profile of SAP rat pancreas tissue was investigated using RNA sequencing. We screened for differentially expressed genes (DEGs). Quantitative real-time PCR (qRT-PCR) measured critical DEG mRNA expression in rat pancreatic tissues. Results: Dex attenuated SAP-induced pancreatic injury, infiltration of neutrophils and macrophages, and oxidative stress. Dex inhibited the expression of necroptosis-associated proteins RIPK1, RIPK3, and MLKL and alleviated apoptosis in acinar cells. Dex also mitigated the structural damage caused by SAP to mitochondria and endoplasmic reticulum. Dex inhibited SAP-induced 473 DEGs, as determined by RNA sequencing. Dex may regulate SAP-induced inflammatory response and tissue damage by inhibiting the toll-like receptor/nuclear factor κB (TLR/NF-κB) signaling pathway and neutrophil extracellular trap formation. Conclusion: This study elucidated the remarkable effect of Dex against SAP and investigated the potential mechanism of action, providing an experimental base for the future clinical application of Dex in the treatment of SAP.

The Sympathetic Nervous System in Dental Implantology

The sympathetic nervous system plays a vital role in various regulatory mechanisms. These include the well-known fight-or-flight response but also, for example, the processing of external stressors. In addition to many other tissues, the sympathetic nervous system influences bone metabolism. This effect could be highly relevant concerning osseointegration, which is responsible for the long-term success of dental implants. Accordingly, this review aims to summarize the current literature on this topic and to reveal future research perspectives. One in vitro study showed differences in mRNA expression of adrenoceptors cultured on implant surfaces. In vivo, sympathectomy impaired osseointegration in mice, while electrical stimulation of the sympathetic nerves promoted it. As expected, the beta-blocker propranolol improves histological implant parameters and micro-CT measurements. Overall, the present data are considered heterogeneous. However, the available publications reveal the potential for future research and development in dental implantology, which helps to introduce new therapeutic strategies and identify risk factors for dental implant failure.

Association of Dexmedetomidine With New-Onset Atrial Fibrillation in Patients With Critical Illness

Importance

Dexmedetomidine is a widely used sedative in the intensive care unit (ICU) and has unique properties that may be associated with reduced occurrence of new-onset atrial fibrillation (NOAF).

Objective

To investigate whether the use of dexmedetomidine is associated with the incidence of NOAF in patients with critical illness.

Design, Setting, and Participants

This propensity score-matched cohort study was conducted using the Medical Information Mart for Intensive Care-IV database, which includes records of patients admitted to the ICU at Beth Israel Deaconess Medical Center in Boston dating 2008 through 2019. Included patients were those aged 18 years or older and hospitalized in the ICU. Data were analyzed from March through May 2022.

Exposure

Patients were divided into 2 groups according to dexmedetomidine exposure: those who received dexmedetomidine within 48 hours after ICU admission (dexmedetomidine group) and those who never received dexmedetomidine (no dexmedetomidine group).

Main Outcomes and Measures

The primary outcome was the occurrence of NOAF within 7 days of ICU admission, as defined by the nurse-recorded rhythm status. Secondary outcomes were ICU length of stay, hospital length of stay, and in-hospital mortality.

Results

This study included 22 237 patients before matching (mean [SD] age, 65.9 [16.7] years; 12 350 male patients [55.5%]). After 1:3 propensity score matching, the cohort included 8015 patients (mean [SD] age, 61.0 [17.1] years; 5240 males [65.4%]), among whom 2106 and 5909 patients were in the dexmedetomidine and no dexmedetomidine groups, respectively. Use of dexmedetomidine was associated with a decreased risk of NOAF (371 patients [17.6%] vs 1323 patients [22.4%]; hazard ratio, 0.80; 95% CI, 0.71-0.90). Although patients in the dexmedetomidine group had longer median (IQR) length of stays in the ICU (4.0 [2.7-6.9] days vs 3.5 [2.5-5.9] days; P < .001) and hospital (10.0 [6.6-16.3] days vs 8.8 [5.9-14.0] days; P < .001), dexmedetomidine was associated with decreased risk of in-hospital mortality (132 deaths [6.3%] vs 758 deaths [12.8%]; hazard ratio, 0.43; 95% CI, 0.36-0.52).

Conclusions and Relevance

This study found that dexmedetomidine was associated with decreased risk of NOAF in patients with critical illness, suggesting that it may be necessary and warranted to evaluate this association in future clinical trials.

Correlation between perioperative dexmedetomidine administration and postoperative acute kidney injury in hypertensive patients undergoing non-cardiac surgery

Background: Previous studies have suggested that dexmedetomidine may have a protective effect on renal function. However, it is currently unclear whether perioperative dexmedetomidine administration is associated with postoperative acute kidney injury (AKI) incidence risk in hypertensive patients undergoing non-cardiac surgery.

Methods: This investigation was a retrospective cohort study. Hypertensive patients undergoing non-cardiac surgery in Third Xiangya Hospital of Central South University from June 2018 to December 2019 were included. The relevant data were extracted through electronic cases. The univariable analysis identified demographic, preoperative laboratory, and intraoperative factors associated with acute kidney injury. Multivariable stepwise logistic regression was used to assess the association between perioperative dexmedetomidine administration and postoperative acute kidney injury after adjusting for interference factors. In addition, we further performed sensitivity analyses in four subgroups to further validate the robustness of the results.

Results: A total of 5769 patients were included in this study, with a 7.66% incidence of postoperative acute kidney injury. The incidence of postoperative acute kidney injury was lower in the dexmedetomidine-administered group than in the control group (4.12% vs. 8.06%, p &lt; 0.001). In the multivariable stepwise logistic regression analysis, perioperative dexmedetomidine administration significantly reduced the risk of postoperative acute kidney injury after adjusting for interference factors [odds ratio (OR) = 0.56, 95% confidence interval (CI): 0.36–0.87, p = 0.010]. In addition, sensitivity analysis in four subgroups indicated parallel findings: i) eGRF &lt;90 mL/min·1.73/m2 subgroup (OR = 0.40, 95% CI: 0.19–0.84, p = 0.016), ii) intraoperative blood loss &lt;1000 mL subgroup (OR = 0.58, 95% CI: 0.36–0.94, p = 0.025), iii) non-diabetes subgroup (OR = 0.51, 95% CI: 0.29–0.89, p = 0.018), and iv) older subgroup (OR = 0.55, 95% CI: 0.32–0.93, p = 0.027).

Conclusion: In conclusion, our study suggests that perioperative dexmedetomidine administration is associated with lower risk and less severity of postoperative acute kidney injury in hypertensive individuals undergoing non-cardiac surgery. Therefore, future large-scale RCT studies are necessary to validate this benefit.

Modern Sedation and Analgesia Strategies in Neurocritical Care

PURPOSE OF REVIEW

Patients with acute neurologic injury require a specialized approach to critical care, particularly with regard to sedation and analgesia. This article reviews the most recent advances in methodology, pharmacology, and best practices of sedation and analgesia for the neurocritical care population.

RECENT FINDINGS

In addition to established agents such as propofol and midazolam, dexmedetomidine and ketamine are two sedative agents that play an increasingly central role, as they have a favorable side effect profile on cerebral hemodynamics and rapid offset can facilitate repeated neurologic exams. Recent evidence suggests that dexmedetomidine is also an effective component when managing delirium. Combined analgo-sedation with low doses of short-acting opiates is a preferred sedation strategy to facilitate neurologic exams as well as patient-ventilator synchrony. Optimal care for patients in the neurocritical care population requires an adaptation of general ICU strategies that incorporates understanding of neurophysiology and the need for close neuromonitoring. Recent data continues to improve care tailored to this population.

Effects of Dexmedetomidine on Brain and Inflammatory Outcomes In Pediatric Cardiac Surgery: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

OBJECTIVE

Dexmedetomidine use decreases adverse neurocognitive outcomes in adults undergoing cardiovascular surgery, but its effect has been unclear in children with congenital heart disease.

METHODS

The authors conducted a systematic review using the PubMed, Embase, and Cochrane Library databases for randomized controlled trials (RCTs) that compared intravenous dexmedetomidine with normal saline during pediatric cardiac surgery under anesthesia. Published randomized controlled trials that evaluated children aged <18 years who underwent congenital heart surgery were included. Nonrandomized trials, observational studies, case series and case reports, editorials, reviews, and conference papers were excluded. The quality of the included studies was assessed using the Cochrane revised tool for assessing risk-of-bias in randomized trials. Meta-analysis was performed to estimate the effects of intravenous dexmedetomidine on brain markers (neuron-specific enolase [NSE], S-100β protein) and inflammatory markers (interleukin-6, tumor necrosis factor [TNF]-α, nuclear factor kappa-B [NF-κB]) during and after cardiac surgery, using random-effect models for standardized mean difference (SMD).

RESULTS

Seven RCTs involving 579 children were eligible for the following meta-analyses. Most children underwent cardiac surgery for atrial or ventricular septum defects. Pooled analyses (5 treatment groups in 3 RCTs with 260 children) showed that dexmedetomidine use was associated with reduced serum levels of NSE (pooled SMD, -0.54; 95% CI, -0.96 to -0.12) and S-100β (pooled SMD, -0.85; 95% CI, -1.67 to -0.04) within 24 hours after the surgery. Also, dexmedetomidine use was associated with reduced levels of interleukin-6 (pooled SMD, -1.55; 95% CI, -2.82 to -0.27; 4 treatment groups in 2 RCTs with 190 children). In contrast, the authors observed similar levels of TNF-α (pooled SMD, -0.07; 95% CI, -0.33 to 0.19; 4 treatment groups in 2 RCTs with 190 children) and NF-κB (pooled SMD, -0.27; 95% CI, -0.62 to 0.09; 2 treatment groups in 1 RCT with 90 children) between the dexmedetomidine and control groups.

CONCLUSIONS

The authors' findings support the effect of dexmedetomidine on reductions in brain markers among children who undergo cardiac surgery. Further studies would be needed to elucidate its clinically meaningful effects using cognitive functions in the long term, and its effects among children who undergo more complex cardiac surgeries.

Dexmedetomidine provides type-specific tumour suppression without tumour-enhancing effects in syngeneic murine models

BACKGROUND

Dexmedetomidine is a widely used anaesthetic adjuvant for cancer resection surgeries. However, recent reports suggest that it may promote tumour growth or metastasis, so it is essential to clarify its tumour-related effects.

METHODS

Seven syngeneic murine tumour models were used to assess the impact of dexmedetomidine on primary tumour growth, spontaneous tumour metastasis, and surgical resection-associated metastasis. Cancer cell proliferation and apoptosis experiments, terminal deoxynucleotidyl transferase dUTP nick-end labelling assays, immune cell analysis, specific T-cell depletion experiments, and gene transcription analysis were conducted to identify the underlying mechanisms.

RESULTS

Dexmedetomidine did not affect growth of EO771 or 4T1 breast tumours, LAP0297 or LLC lung tumours, MCA205 fibrosarcoma, or their spontaneous lung metastases. It did not promote lung metastasis after breast cancer resection. Dexmedetomidine significantly suppressed MCA38 and CT26 colorectal tumour growth (P<0.01) and promoted apoptosis in MCA38 tumour tissues (P<0.05) without affecting proliferation and apoptosis of MCA38 tumour cells in vitro, suggesting indirect anti-tumour effects. Dexmedetomidine increased the proportions of intratumour CD4⁺ T (P<0.01), CD8⁺ T (P<0.001), and natural killer cells (P<0.01), and it upregulated transcription of the cytotoxicity-related genes Infg, Tnfa, and Cxcl9 (P<0.05) in MCA38 tumours. Either CD8⁺ or CD4⁺ T-cell depletion reversed the anti-tumour effects of dexmedetomidine on MCA38 tumours (P<0.05).

CONCLUSIONS

Dexmedetomidine conferred colorectal tumour-type specific suppression by modulation of tumour CD4⁺ and CD8⁺ T cells without tumour-enhancing effects.

Combination of ion-pair strategy and chemical enhancers for design of dexmedetomidine long-acting patches: Dual action mechanism induced longer controlled release and better delivery efficiency

The purpose of this study was to prepare a dexmedetomidine (Dex) 72 h long-acting patch by the combined use of ion-pair strategy and chemical enhancers (CEs), and to investigate molecular mechanisms of drug-loading enhancement and controlled release. The formulation of patch was optimized by single-factor investigation and Box-Behnken design. The pharmacokinetics, analgesic pharmacodynamics and irritation of the formulation were evaluated, respectively. Moreover, the effects of ion-pairs and CEs on the patch were characterized by DSC, rheology study, FTIR, and molecular docking, and the effects on the skin were evaluated by Attenuated Total Reflection Fourier Transform Infrared Spectroscopy (ATR-FTIR), Raman study, and molecular dynamics, respectively. The optimized formulation was 17.00 % (w/w) Dex-NA (Naphthoic acid), 7.20 % Polyglyceryl-3 dioleate (POCC), 25-AAOH as pressure sensitive adhesives (PSA) and 66.50 μm in thickness. Compared with the control group (C_max = 62.02 ± 16.55 ng/mL, MRT_0-t = 26.74 ± 1.27 h), the pharmacokinetics behavior of the optimization group was more stable and durable (C_max = 31.22 ± 13.26 ng/mL, MRT_0-t = 33.62 ± 1.62 h). Besides, it also showed good analgesic effect and no obvious irritation. The results indicated that Dex-NA both increased the drug-PSA interactions and inhibited the penetration of the drug into the skin. POCC increased the molecular mobility of the PSA and disrupted skin lipids thereby improving the drug penetration rate. In summary, the Dex long-acting patch was developed, which provided a reference for the combined application of ion-pair strategy and CEs in other long-acting transdermal delivery.

Effects of Dexmedetomidine on Systemic Inflammation and Postoperative Complications in Laparoscopic Pancreaticoduodenectomy: A Double-blind Randomized Controlled Trial

BACKGROUND

Laparoscopic pancreaticoduodenectomy (LPD) may induce intense inflammatory response which might be related to the patient's outcomes. Clinical dexmedetomidine (DEX) has been widely used for opioid-sparing anesthesia and satisfactory sedation. The objective of this study was to investigate the influence of DEX on inflammatory response and postoperative complications in LPD.

METHODS

Ninety-nine patients undergoing LPD were randomly assigned to two groups: normal saline (NS) and DEX. The primary outcome was the neutrophil-to-lymphocyte ratio (NLR) differences postoperatively within 48 h. Secondary outcomes were postoperative complications, the length of postoperative hospital stay and the incidence of ICU admission. Other outcomes included anesthetics consumption and intraoperative vital signs.

RESULTS

NLR at postoperative day 2 to baseline ratio decreased significantly in the DEX group (P = 0.032). Less major complications were observed in the DEX group such as pancreatic fistula, delayed gastric emptying and intra-abdominal infection (NS vs. DEX, 21.7% vs. 13.6%, P = 0.315; 10.9% vs. 2.3%, P = 0.226; 17.4% vs. 11.4%, P = 0.416, respectively) though there were no statistical differences. Three patients were transferred to the ICU after surgery in the NS group, while there was none in the DEX group (P = 0.242). The median postoperative hospital stay between groups were similar (P = 0.313). Both intraoperative propofol and opioids were less in the DEX group (P < 0.05).

CONCLUSIONS

Intraoperative DEX reduced the early postoperative inflammatory response in LPD. It also reduced the use of narcotics that may related to reduced major complications, which need additional research further.

Comparison of Efficacy and Safety of Different Doses of Dexmedetomidine for Epidural Labor Analgesia

Objective

To explore the efficacy and safety of different doses of dexmedetomidine (DEX) for epidural labor analgesia (ELA).

Methods

From June 2021 to June 2022, 147 parturients who underwent ELA in our hospital were selected and divided into low- (0.5 μg/kg DEX), medium- (0.75 μg/kg DEX), and high-dose (1.0 μg/kg DEX) groups (n = 49 for each) according to the random number table method. The analgesic effect was assessed using the Ramsay sedation score and Visual Analogue Scale (VAS), and the labor duration, mean arterial pressure (MAP), and heart rate (HR) before and after analgesia, vaginal bleeding within 2 h postpartum, and delivery outcomes (the cesarean section conversion rate and the neonatal Apgar score) were statistically analyzed. Furthermore, the incidence of adverse reactions was calculated, and maternal satisfaction with delivery was investigated.

Results

After analgesia, the the Ramsay and labor duration were higher in the high-dose group than those in the low- and medium-dose groups, and the VAS scores was lowerin the high-dose group than those in the low- and medium-dose groups(P < 0.05), while no difference was identified among the three groups in terms of the cesarean section conversion rate and the neonatal Apgar score (P > 0.05). The high-dose group had the greatest fluctuations in MAP and HR levels before and after analgesia than the other two groups, with a higher incidence of adverse reactions (P < 0.05). Finally, the survey of delivery satisfaction showed no significant difference in delivery satisfaction among the three groups (P > 0.05).

Conclusion

DEX has excellent performance in ELA, which can effectively relieve the pain of puerperae and shorten the labor process. Among them, low-dose DEX has higher safety and is recommended as the first choice. Trial Registrations. This trial is registered with ML2021073.

Effects of Dexmedetomidine on Basic Cardiac Electrophysiology in Adults; a Descriptive Review and a Prospective Case Study

Dexmedetomidine (DEX) is a commonly used sedative agent with no or minimal effects on breathing. DEX may also be beneficial in myocardial protection. Since the mechanisms of cardiac effects are not well known, we carried out a descriptive review and examined the effects of DEX on myocardial electrical conduction in a prospective and controlled manner. For the review, clinical studies exploring DEX in myocardial protection published between 2020-2022 were explored. A case study included 11 consecutive patients at a median (range) age of 48 (38-59), scheduled for elective radiofrequency ablation of paroxysmal atrial fibrillation. A bolus dose of DEX 1 µg/kg given in 15 min was followed by a continuous infusion of 0.2-0.7 µg/kg/h. Direct intracardiac electrophysiologic measurements, hemodynamics and oxygenation were measured before and after the DEX bolus. Experimental studies show that DEX protects the heart both via stabilizing cardiac electrophysiology and reducing apoptosis and autophagy after cell injury. The clinical evidence shows that DEX provides cardiac protection during different surgeries. In a clinical study, DEX increased the corrected sinus node recovery time, prolongated the atrioventricular (AV) nodal refractory period and cycle length producing AV nodal Wenckebach retrograde conduction block. DEX has a putative role in organ protection against hypoxic, oxidative and reperfusion injury. DEX slows down the firing of the sinus node and prolongs AV refractoriness.

Use of dexmedetomidine to alleviate intestinal ischemia-reperfusion injury via intestinal microbiota modulation in mice

Background

Intestinal ischemia-reperfusion (I/R) injury is a serious condition with unacceptable mortality rates. Our previous study revealed a protective effect of dexmedetomidine (DEX) on intestinal I/R injury, but its underlying mechanism remains unclear. Gut microbiota imbalance is associated with the progression of I/R injury. We hypothesized that DEX would attenuate intestinal I/R injury via modulating gut microbiota.

Methods

An I/R injury model was established in C57BL/6 mice in the presence or absence of DEX preconditioning. Some mice were treated with antibiotics to deplete intestinal bacteria. Fecal microbiota transplantation (FMT) was performed by transplanting the feces of DEX-pretreated mice into a new batch of I/R mice. We analyzed the expression of Bacteroidetes and Firmicutes in feces, survival rate, and inflammatory cytokines.

Results

DEX reversed I/R-induced bacterial abnormalities by increasing the ratio of Firmicutes to Bacteroidetes [DEX + I/R 3.02±0.36 vs. normal saline (NS) + I/R 0.82±0.15; 95% CI: 0.80-3.60; P<0.05] and was accompanied by increased 72-hour survival (0.40±0.16 vs. 0.10±0.09; P<0.05). The protective effect of DEX did not significantly differ from that of DEX + antibiotics. Furthermore, the bacteria of the DEX-pretreated mice decreased the release of inflammatory factors.

Conclusions

This study revealed that DEX can alleviate intestinal I/R injury through a microbiota-related mechanism, providing a potential avenue for the management of intestinal I/R injury.

Efficacy of dexmedetomidine versus midazolam when combined with butorphanol for sedation and analgesia during burn dressing changes: A randomized clinical trial

Objective: The aim of this study was to compare dexmedetomidine-butorphanol (DB) and midazolam-butorphanol (MB) combinations for sedation, and analgesia in burn patients undergoing dressing changes.

Methods: A total of 56 ASA I–II burn patients were included in this single-center randomized clinical trial. The ages of these patients were between 20 and 60 years. TBSA ranged from 10% to 50%. They were randomized to group DB and group MB during dressing change. In the DB group, each patient received a bolus dose of dexmedetomidine (0.5 μg kg−1) and intermittent boluses of butorphanol (20 μg kg−1). In the MB group, each patient received a bolus dose of midazolam (0.05 mg kg−1) and intermittent boluses of butorphanol (20 μg kg−1). The primary outcomes were sedation scores and pain scores. The second outcomes were vital signs, side effects, and butorphanol consumption.

Results: The sedation scores of these two groups did not differ significantly (p &gt; 0.05), and the pain scores of these groups were not significantly different (p &gt; 0.05). More patients had hypotension in the DB group than in the MB group (6 versus 0, p = 0.01), but the number of patients who had respiratory depression was higher in the MB group compared with the DB group (4 versus 0, p = 0.038). Butorphanol consumption in the MB group was higher than in the DB group (p = 0.025).

Conclusion: Dexmedetomidine is comparable to midazolam when combined with butorphanol in burn patients during dressing change. Compared with midazolam, it has the advantage of opioid-sparing effect.

Clinical Trial Registration: [http://www.chictr.org.cn/showproj.aspx&amp;proj=130622], identifier [ChiCTR2100049325].

Dexmedetomidine and acute kidney injury following cardiac surgery in pediatric patients—An updated systematic review and meta-analysis

Background

Acute kidney injury (AKI) is a common postoperative complication in pediatric patients undergoing cardiac surgery and associated with poor outcomes. Dexmedetomidine has the pharmacological features of organ protection in cardiac surgery patients. The aim of this meta-analysis is to investigate the effect of dexmedetomidine infusion on the incidence of AKI after cardiac surgery in pediatric patients.

Methods

The databases of Pubmed, Embase, and Cochrane Library were searched until April 24, 2022 following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. RevMan 5.3 was used to perform statistical analyses.

Results

Five relevant trials with a total of 630 patients were included. The pooled result using fixed-effects model with OR demonstrated significant difference in the incidence of AKI between patients with dexmedetomidine and placebo (OR = 0.49, 95% CI: [0.33, 0.73], I² = 0%, p for effect = 0.0004). Subgroup analyses were performed based on congenital heart disease (CHD) types and dexmedetomidine intervention time. Pooled results did not demonstrate considerable difference in the incidence of AKI in pediatric patients receiving intraoperative (OR = 0.53, 95% CI: [0.29, 0.99], I² = 0%, p for effect = 0.05) or postoperative dexmedetomidine infusion (OR = 0.56, 95% CI: [0.31, 1.04], p for effect = 0.07), but a significant difference in patients receiving combination of intra- and postoperative dexmedetomidine infusion (OR = 0.27, 95% CI: [0.09, 0.77], p for effect = 0.01). Besides, there was no significant difference in duration of mechanical ventilation (SMD: –0.19, 95% CI: –0.46 to 0.08, p for effect = 0.16; SMD: –0.16, 95% CI: –0.37 to 0.06, p for effect = 0.15), length of ICU (SMD: 0.02, 95% CI: –0.41 to 0.44, p for effect = 0.93) and hospital stay (SMD: 0.2, 95% CI: –0.13 to 0.54, p for effect = 0.23), and in-hospital mortality (OR = 1.26, 95% CI: 0.33–4.84, p for effect = 0.73) after surgery according to the pooled results of the secondary outcomes.

Conclusion

Compared to placebo, dexmedetomidine could significantly reduce the postoperative incidence of AKI in pediatric patients undergoing cardiac surgery with cardiopulmonary bypass (CPB), but the considerable difference was reflected in the pediatric patients receiving combination of intra- and postoperative dexmedetomidine infusion. Besides, there was no significant difference in duration of mechanical ventilation, length of ICU and hospital stay, or in-hospital mortality after surgery.

CYP2A6 and GABRA2 Gene Polymorphisms are Associated With Dexmedetomidine Drug Response

Background: Dexmedetomidine is a commonly used clinical sedative; however, the drug response varies among individuals. Thus, the purpose of this study was to explore the association between dexmedetomidine response and gene polymorphisms related to drug-metabolizing enzymes and drug response (CYP2A6, UGT2B10, UGT1A4, ADRA2A, ADRA2B, ADRA2C, GABRA1, GABRB2, and GLRA1).

Methods: This study was a prospective cohort study. A total of 194 female patients aged 18–60 years, American Society of Anesthesiologists (ASA) score I-II, who underwent laparoscopy at the Third Xiangya Hospital of Central South University, were included. The sedative effect was assessed every 2 min using the Ramsay score, and the patient’s heart rate decrease within 20 min was recorded. Peripheral blood was collected from each participant to identify genetic variants in the candidate genes of metabolic and drug effects using the Sequenom MassARRAY^® platform. Furthermore, additional peripheral blood samples were collected from the first 99 participants at multiple time points after dexmedetomidine infusion to perform dexmedetomidine pharmacokinetic analysis by Phoenix^® WinNonlin 7.0 software.

Results: Carriers of the minor allele (C) of CYP2A6 rs28399433 had lower metabolic enzyme efficiency and higher plasma concentrations of dexmedetomidine. In addition, the participants were divided into dexmedetomidine sensitive or dexmedetomidine tolerant groups based on whether they had a Ramsay score of at least four within 20 min, and CYP2A6 rs28399433 was identified to have a significant influence on the dexmedetomidine sedation sensitivity by logistic regression with Plink software [p = 0.003, OR (95% CI): 0.27 (0.11–0.65)]. C allele carriers were more sensitive to the sedative effects of dexmedetomidine than A allele carriers. GABRA2 rs279847 polymorphism was significantly associated with the degree of the heart rate decrease. In particular, individuals with the GG genotype had a 4-fold higher risk of heart rate abnormality than carriers of the T allele (OR = 4.32, 95% CI: 1.96–9.50, p = 0.00027).

Conclusion:CYP2A6 rs28399433 polymorphism affects the metabolic rate of dexmedetomidine and is associated with susceptibility to the sedative effects of dexmedetomidine; GABRA2 rs279847 polymorphism is significantly associated with the degree of the heart rate decrease.

A Loading Dose of Dexmedetomidine With Constant Infusion Inhibits Intraoperative Neuromonitoring During Thoracic Spinal Decompression Surgery: A Randomized Prospective Study

Background: The effect of a bolus dose of dexmedetomidine on intraoperative neuromonitoring (IONM) parameters during spinal surgeries has been variably reported and remains a debated topic. Methods: A randomized, double-blinded, placebo-controlled study was performed to assess the effect of dexmedetomidine (1 μg/kg in 10 min) followed by a constant infusion rate on IONM during thoracic spinal decompression surgery (TSDS). A total of 165 patients were enrolled and randomized into three groups. One group received propofol- and remifentanil-based total intravenous anesthesia (TIVA) (T group), one group received TIVA combined with dexmedetomidine at a constant infusion rate (0.5 μg kg-1 h-1) (D1 group), and one group received TIVA combined with dexmedetomidine delivered in a loading dose (1 μg kg-1 in 10 min) followed by a constant infusion rate (0.5 μg kg-1 h-1) (D2 group). The IONM data recorded before test drug administration was defined as the baseline value. We aimed at comparing the parameters of IONM. Results: In the D2 group, within-group analysis showed suppressive effects on IONM parameters compared with baseline value after a bolus dose of dexmedetomidine. Furthermore, the D2 group also showed inhibitory effects on IONM recordings compared with both the D1 group and the T group, including a statistically significant decrease in SSEP amplitude and MEP amplitude, and an increase in SSEP latency. No significance was found in IONM parameters between the T group and the D1 group. Conclusion: Dexmedetomidine delivered in a loading dose can significantly inhibit IONM parameters in TSDS. Special attention should be paid to the timing of a bolus dose of dexmedetomidine under IONM. However, dexmedetomidine delivered at a constant speed does not exert inhibitory effects on IONM data.