Dexmedetomidine Improves Cardiovascular and Ventilatory Outcomes in Critically Ill Patients: Basic and Clinical Approaches

Immunotherapeutic Properties of Dexmedetomidine on Pain Management and Cardiovascular Function in Videolaparoscopic Cholecystectomies: A Randomized, Two-Arm, Double-Blinded, Placebo-Controlled Trial

BACKGROUND

Laparoscopy represented one of the most innovative surgical techniques approached in the surgery field. Dexmedetomidine association with general anesthesia promotes the response control to trauma by altering the neuroinflammatory reflex, provides better clinical outcomes in the postoperative period and reduces the excessive use of drugs with risk for addiction. This trial aims to evaluate the potential drug treatment of dexmedetomidine on organic function, with the targets in neuroinflammation, perioperative pain control and blood pressure measurements in a medium-sized surgical model.

METHODS

Fifty-two patients were randomized in two groups: Sevoflurane and Dexmedetomidine - A (dexmedetomidine infusion [1 μg/kg loading, .2-.5 μg/kg/h thereafter]) vs Sevoflurane and Saline .9% - B. Three blood samples were collected at three times: before surgery, 4 to 6 hours after surgery and 24 hours postoperatively. The primary outcome was inflammatory and endocrine mediators dosage analisys. Finally, we evaluated pain and opioid use as secondary outcomes, also the hemodynamic values.

RESULTS

In Dexmedetomidine group A, a reduction of Interleukin 6 was found during 4-6 hours after surgery. A reduction of IL-10 was noted in the measurement of its values 24 hours after the procedure, with statistical significance. Also, systolic and diastolic blood pressure, as well heart rate were attenuated, and there was a lower incidence of pain and opioid consumption in the first postoperative hour (P < .0001) in the anesthetic recovery room.

CONCLUSIONS

Dexmedetomidine provided anti-inflammatory activity, sympatholytic effect and analgesia with cardiovascular safety. It reinforces the therapeutic nature of highly selective α2-adrenergic agonists when combined within anesthetic interventions.

Premedication with intranasal versus intravenous dexmedetomidine for hypotensive anesthesia during functional endoscopic sinus surgery in adults: A randomized triple-blind trial

Functional Endoscopic Sinus Surgery (FESS) has been performed under controlled hypotension to increase operating field visibility. Intranasal (IN) dexmedetomidine is easy, noninvasive, and possesses lower C max, accompanied by lower pharmacodynamic action, including hypotension, bradycardia, and sedation. This trial aimed to compare IN and intravenous (IV) dexmedetomidine for hypotensive anesthesia during FESS. This randomized, controlled, triple-blinded clinical trial involved sixty cases scheduled for FESS. Patients were divided into two equal groups by random manner. 45-60 min before anesthesia induction, group IN: received 1 μg/kg IN dexmedetomidine diluted in 10 ml of saline 0.9 % intranasally preoperative. Group IV: received 1 μg/kg dexmedetomidine diluted in 10 ml of saline 0.9 % infused over 10 min. The primary outcome was the total amount of administered atropine. The secondary outcomes included hemodynamic, through 1 h before surgery, intraoperatively and postoperatively at different time intervals. The quality of the operative field, sedation, adverse reactions and hemostatic stuffing after FESS were also assessed. The total amount of consumed atropine decreased significantly in group IN compared to group IV. Preoperative Ramsay Sedation scores at T0, T5, T50 and T60 were comparable between the two groups, while at T10, T15, T20, T30, and T40 were lower significantly in the IN group compared with the IV group. Preoperative mean arterial blood pressure at T0, T5 and T60 had comparable differences across both groups while reduced at T10 to T 45 significantly in the IV group than IN group. Both groups had comparable satisfaction, postoperative Ramsey sedation, hemostatic suffering, quality of operative field and complications. In conclusion, IN dexmedetomidine administration is relatively simple and appropriate; moreover, it decreases first-pass metabolism. Onset is prolonged relative to IV dosing; thus, it should be administered nearly 1 h before surgery and recommended in adult patients as they require minor sedation preoperatively.

Incidence, associated factors, and outcomes of delirium in critically ill children in china: a prospective cohort study

BACKGROUND

Delirium occurs frequently in critically ill children and has been reported in many countries, but delirium is not well-characterized in China. The aim of this study was to represent the incidence of delirium in critically ill children in China, its associated factors, and the influence of delirium on in-hospital outcomes.

METHODS

This observational prospective cohort study was set up in a large academic medical center with a 57-bed PICU in southwestern China. Critically ill children who required PICU stays over 24 h and were admitted between November 2019 and February 2022 were included in this study. The Cornell Assessment of Pediatric Delirium was used twice daily for delirium evaluation by bedside nurses, and twenty-four clinical features were collected from medical and nursing records during hospitalization.

RESULTS

The incidence of delirium was 26.0% (n = 410/1576). Multivariate analysis revealed that seven independent risk factors including days of mechanical ventilation and physical restraints, admission diagnosis (neurologic disorder), sleep deprivation, use of benzodiazepines and dexmedetomidine, liver failure/liver dysfunction associated with delirium in critically ill children. One potentially protective factor was the watching television /listening to music/playing with toys. Children with delirium had longer lengths of stay in the PICU (median 11 vs. 10 days, p < 0.001) and hospital (median 18 vs. 15 days, p < 0.001) compared to those without delirium. Additionally, the in-hospital mortality rates were 4.63% and 0.77% in patients with and without delirium (p < 0.05).

CONCLUSIONS

Delirium is common in critically ill children in China and related to poor outcomes. Interventional studies are warranted to determine the best practices to reduce delirium exposure in at-risk children.

Dexmedetomidine as a myocardial protector in pediatric heart surgery using cardiopulmonary bypass: a systematic review

Background

In recent years, dexmedetomidine has been studied as a cardioprotective agent. However, studies on its application in pediatric heart surgery using cardiopulmonary bypass (CPB) remain limited. This systematic review aimed to provide information on the cardioprotective effect of dexmedetomidine in children undergoing heart surgery using CPB.

Methods

The authors searched several databases (MEDLINE, Embase, Cochrane Library, etc.) to identify all trials comparing the levels of myocardial injury via biomarkers, including pediatric patients undergoing heart surgery using CPB who received dexmedetomidine versus placebo or other anesthetic agents. Literatures from non-primary studies were excluded. Two reviewers independently screened studies for eligibility and extracted data. The Cochrane Risk-of-Bias tool was implemented to evaluate any potential biases. Information from eligible studies was summarized and correspondingly reviewed based on any quantitative outcomes.

Results

We identified six trials composed of 419 participants, three of which (n=241) showed significantly reduced interleukin-6 (IL-6) levels in the dexmedetomidine group, while one study (n=40) showed no IL-6 difference between groups. Cardiac troponin I (cTnI) and creatinine kinase-myocardial band (CK-MB), as myocardial injury biomarkers, were found to be lower in two trials (n=180). Despite several limitations hindering this review from pooling the data objectively, the majority of published studies indicated that dexmedetomidine is a seemingly efficacious agent protecting against cardiac injury during bypass.

Conclusions

These studies suggest that dexmedetomidine has cardioprotective effects through the lowering of cardiac injury biomarkers while improving its clinical outcomes after heart surgery using bypass.

Intraoperative infusion of dexmedetomidine for prevention of postoperative delirium in elderly patients undergoing craniotomy: a protocol of randomised clinical trial

INTRODUCTION

Postoperative delirium (POD) is a common surgical complication. The incidence is 19% in neurological procedures, and advanced age is a risk factor for neurological procedures. Many studies have shown that dexmedetomidine (DEX) reduced the incidence of delirium after non-cardiac surgery in elderly patients. However, there are few studies focus on the effect of DEX on POD in elderly patients undergoing neurosurgery.

METHODS AND ANALYSIS

This is a randomised, double-blinded, paralleled-group and controlled trial. Patients older than 65 years and scheduled for elective craniotomy will be randomly assigned to the DEX group and the control group. After endotracheal intubation, patients in the DEX group will be administered with continuous DEX infusion at rate of 0.4 µg/kg/hour until the surgical haemostasis. In the control group, patients will receive the identical volume of normal saline in the same setting. The primary outcome is the incidence of POD during the first 5 days. Delirium will be evaluated through a combination of three methods, including the Richmond Agitation Sedation Scale (RASS), the confusion assessment method for ICU (CAM-ICU) and the 3 min diagnostic interview for CAM (3D-CAM). The RASS, CAM-ICU and 3D-CAM will be evaluated two times per day (08:00-10:00 and 18:00-20:00 hours) during the first postoperative 5 days. Secondary outcomes include pain severity score, quality of recovery, quality of sleep, cognitive function, psychological health state, intraoperative data, physiological status, length of stay in ICU and hospital, hospitalisation costs, non-delirium complications, and 30-day all-cause mortality.

ETHICS AND DISSEMINATION

The protocol (V.4.0) has been approved by the medical ethics committee of Beijing Tiantan Hospital, Capital Medical University (KY2021-194-03). The findings of the study will be disseminated in a peer-reviewed journal and at a scientific conference.

TRIAL REGISTRATION NUMBER

NCT05168280.

Dexmedetomidine Attenuates Methotrexate-Induced Neurotoxicity and Memory Deficits in Rats through Improving Hippocampal Neurogenesis: The Role of miR-15a/ROCK-1/ERK1/2/CREB/BDNF Pathway Modulation

Methotrexate (MTX) is a widely used neurotoxic drug with broad antineoplastic and immunosuppressant spectra. However, the exact molecular mechanisms by which MTX inhibits hippocampal neurogenesis are yet unclear. Dexmedetomidine (Dex), an α2-adrenergic receptor agonist, has recently shown neuroprotective effects; however, its full mechanism is unexplored. This study investigated the potential of Dex to mitigate MTX-induced neurotoxicity and memory impairment in rats and the possible role of the miR-15a/ROCK-1/ERK1/2/CREB/BDNF pathway. Notably, no former studies have linked this pathway to MTX-induced neurotoxicity. Male Sprague Dawley rats were placed into four groups. Group 1 received saline i.p. daily and i.v. on days 8 and 15. Group 2 received Dex at 10 μg/kg/day i.p. for 30 days. Group 3 received MTX at 75 mg/kg i.v. on days 8 and 15, followed by four i.p. doses of leucovorin at 6 mg/kg after 18 h and 3 mg/kg after 26, 42, and 50 h. Group 4 received MTX and leucovorin as in group 3 and Dex daily dosages as in group 2. Bioinformatic analysis identified the association of miR-15a with ROCK-1/ERK1/2/CREB/BDNF and neurogenesis. MTX lowered hippocampal doublecortin and Ki-67, two markers of neurogenesis. This was associated with the downregulation of miR-15a, upregulation of its target ROCK-1, and reduction in the downstream ERK1/2/CREB/BDNF pathway, along with disturbed hippocampal redox state. Novel object recognition and Morris water maze tests demonstrated the MTX-induced memory deficiencies. Dex co-treatment reversed the MTX-induced behavioral, biochemical, and histological alterations in the rats. These neuroprotective actions could be partly mediated through modulating the miR-15a/ROCK-1/ERK1/2/CREB/BDNF pathway, which enhances hippocampal neurogenesis.

Dexmedetomidine for sedation during epicardial ablation for ventricular tachycardia: a single-center experience

BACKGROUND

Epicardial approach to ventricular tachycardia (VT) ablation is mainly performed under general anesthesia (GA). Although catheter manipulation and ablation in the epicardial space could be painful, GA lowers blood pressure and may interfere with arrhythmia induction and mapping, and the use of muscle relaxants precludes identification of the phrenic nerve (PN). Moreover, an anesthesiologist's presence is required during GA for the whole procedure, which may not always be possible. Therefore, we evaluated the feasibility and safety of epicardial VT ablations performed under conscious sedation using dexmedetomidine in our center.

METHODS

Between January 2018 and January 2022, all patients who underwent epicardial VT ablation under continuous dexmedetomidine infusion were prospectively included in the study. All patients received premedication 30 min before the epicardial puncture with paracetamol (acetaminophen 10 mg/ml) 1000 mg and ketorolac 30 mg. Sedation protocol included an intravenous bolus of midazolam hydrochloride (0.03-0.05 mg/kg) followed by continuous infusion of dexmedetomidine (0.2-0.7 mcg/kg/h). In addition, an intravenous fentanyl citrate bolus (0.7-1.4 mcg/kg) was given for short-term analgesia, followed by a second dose repeated after 30 to 45 min. Sedation-related complications were defined in case of respiratory failure, severe hypotension, and bradycardia requiring treatment.

RESULTS

Sixty-nine patients underwent epicardial or endo-epi VT ablation under conscious sedation and were included in the analysis. The mean age was 65.4 ± 12.1 years; forty-six patients were males (66.6%). All patients had drug-refractory recurrent VT. Forty-seven patients (68.1%) had non-ischemic cardiomyopathy (NICM), 13 patients (18.9%) had ischemic-cardiomyopathy (ICM), and 9 patients (13%) had myocarditis. Standard percutaneous sub-xiphoid access was attempted in all patients. Non-inducibility of any VT was achieved in 82.6% (9/9 myocarditis, 10/13 ICM, 38/47 NICM, n = 57/69 patients), inducibility of non-clinical VT in 13% (3/13 ICM, 6/38 NICM, n = 9/69 patients), and failure in 4.3% (3/38 NICM, n = 3/69 patients). Although we observed procedural-related complications in five patients (7.2%), one transient PN palsy, two pericarditis, and two vascular complications, those were not related to the conscious sedation protocol. No respiratory failure, severe hypotension, or bradycardia requiring treatment has been observed among the patients.

CONCLUSIONS

Prompt availability of anesthesiology support remains crucial for complex procedures such as epicardial VT ablation. Continuous infusion of dexmedetomidine and administration of midazolam and fentanyl seem to be a safe and effective sedation protocol in patients undergoing epicardial VT ablation.

Determination of the effective dose of dexmedetomidine to achieve loss of consciousness during anesthesia induction

Background

Dexmedetomidine (DEX) is a sedative with greater preservation of cognitive function, reduced respiratory depression, and improved patient arousability. This study was designed to investigate the performance of DEX during anesthesia induction and to establish an effective DEX induction strategy, which could be valuable for multiple clinical conditions.

Methods

Patients undergoing abdominal surgery were involved in this dose-finding trial. Dixon's up-and-down sequential method was employed to determine the effective dose of DEX to achieve the state of "loss of consciousness", and an effective induction strategy was established with continuous infusion of DEX and remifentanil. The effects of DEX on hemodynamics, respiratory state, EEG, and anesthetic depth were monitored and analyzed.

Results

Through the strategy mentioned, the depth of surgical anesthesia was successfully achieved by DEX-led anesthesia induction. The ED50 and ED95 of the initial infusion rate of DEX were 0.115 and 0.200 μg/kg/min, respectively, and the mean induction time was 18.3 min. The ED50 and ED95 of DEX to achieve the state of "loss of consciousness" were 2.899 (95% CI: 2.703-3.115) and 5.001 (95% CI: 4.544-5.700) μg/kg, respectively. The mean PSI on the loss of consciousness was 42.8 among the patients. During anesthesia induction, the hemodynamics including BP and HR were stable, and the EEG monitor showed decreased α and β powers and increased θ and δ in the frontal and pre-frontal cortices of the brain.

Conclusion

This study indicated that continuous infusion of combined DEX and remifentanil could be an effective strategy for anesthesia induction. The EEG during the induction was similar to the physiological sleep process.

Analysis of anesthetic effect of dexmedetomidine in femoral shaft fracture surgery

To investigate the effect of dexmedetomidine (DEX) on hemodynamics and recovery period after femoral shaft fracture surgery. Fifty-two patients, aged 3 to 7 years, who underwent femoral shaft fracture reduction surgery in our hospital in 2019 were randomly divided into the experimental group (n = 26) and the control group (n = 26). Both groups were given routine propofol combined with remifentanil by intravenous anesthesia. The experimental group was continuously pumped with DEX after induction of anesthesia, while the control group was continuously pumped with the same volume of normal saline. The mean arterial pressure (MAP) and heart rate (HR) were recorded before anesthesia induction (T0), when laryngeal mask was inserted (T1), when skin was cut (T2), when intramedullary needle was inserted (T3), and when laryngeal mask was removed (T4). Extubation time after anesthesia withdrawal was recorded in the 2 groups. According to the Pediatric Anesthesia Emergence Delirium score, the agitation and the incidence of agitation were recorded immediately after extubation (T5), 10 minutes after entering the recovery room (T6) and 30 minutes after entering the recovery room (T7). There was no significant difference in MAP and HR between the 2 groups at T0 and T1 time points (P > .05). The MAP and HR of the experimental group at T2 to T4 were significantly lower than those of the control group (P < .05). The extubation time of the experimental group was longer than that of the control group (P < .05), but the Pediatric Anesthesia Emergence Delirium score and the incidence of agitation in the recovery period of the experimental group were lower than those of the control group (P < .05). In femoral shaft fracture surgery, intravenous anesthesia combined with continuous pumping DEX can effectively stabilize the hemodynamics of patients, and the incidence of postoperative agitation during anesthesia recovery is low.

The Choice of Anesthetic Drugs in Outpatient Hysteroscopic Surgery: A Systematic Review and Network Meta-Analysis

Objective

Hysteroscopy is a minimally invasive gynecologic technique that is widely practiced in outpatient procedures. The choice of anesthesia is a key factor for the surgical outcome and postoperative recovery. This study was conducted to assess the effects of different anesthetic modalities based on dexmedetomidine in outpatient hysteroscopic surgery anesthesia.

Methods

We did a systematic review and network meta-analysis of outpatient hysteroscopic surgery anesthesia. We searched Pubmed, Embase, and Cochrane-Library from database inception to December 31, 2021. Duplicate literature was excluded and screened separately for initial screening at three tiers: article title, abstract, and full text before deciding whether to include in this study against the above criteria. Results after analysis of categorical variables were expressed as ORR Ratio (95% CI) and continuous variables were expressed as Mean Difference (95% CI). Data collation and analyses were performed using the gemtc package in the R language.

Results

Four trials were finally included with data for 301 participants, three anesthetic drugs, and five anesthetic modalities. A fixed-effects model was used for the different anesthesia modalities without significant heterogeneity (all I2<20%) in the analysis of adverse events (AEs), the incidence of respiratory depression, operative time, and time in the post-anesthesia care unit (PACU). Remimazolam tosylate was associated with a lower incidence of AEs versus dexmedetomidine, and significant differences between dexmedetomidine and propofol were absent. Propofol and various doses of remimazolam tosylate resulted in a lower incidence of respiratory depression versus dexmedetomidine, with an absence of differences between propofol and dexmedetomidine. The operative time for different anesthetic modalities was, in descending order, dexmedetomidine < remimazolam tosylate (0.60 mg/kg/h <0.48 mg/kg/h) < propofol < remimazolam tosylate (1.00 mg/kg/h), despite the absence of intergroup differences. Propofol was associated with a longer time in PACU versus dexmedetomidine and remimazolam tosylate (1.00 mg/kg/h); those of dexmedetomidine and remimazolam tosylate (1.00 mg/kg/h) were similar. The time in PACU for different anesthetic modalities, in descending order, was dexmedetomidine < remimazolam tosylate (1.00 mg/kg/h) < propofol. Propofol was associated with a longer time in PACU versus dexmedetomidine and remimazolam tosylate.

Conclusion

In outpatient hysteroscopic surgery anesthesia, dexmedetomidine was associated with a higher incidence of AEs and respiratory depression and a shorter operative time and time in PACU versus remimazolam tosylate and propofol. Remimazolam tosylate showed safety benefits with a similar duration of PACU stay versus dexmedetomidine. Therefore, the choice of anesthetic drugs in outpatient surgery requires consideration of the patient's conditions and preferences.

Amelioration of myocardial ischemia/reperfusion injury in diabetes: A narrative review of the mechanisms and clinical applications of dexmedetomidine

Mechanisms contributing to the pathogenesis of myocardial ischemia-reperfusion (I/R) injury are complex and multifactorial. Many strategies have been developed to ameliorate myocardial I/R injuries based on these mechanisms. However, the cardioprotective effects of these strategies appear to diminish in diabetic states. Diabetes weakens myocardial responses to therapies by disrupting intracellular signaling pathways which may be responsible for enhancing cellular resistance to damage. Intriguingly, it was found that Dexmedetomidine (DEX), a potent and selective α2-adrenergic agonist, appears to have the property to reverse diabetes-related inhibition of most intervention-mediated myocardial protection and exert a protective effect. Several mechanisms were revealed to be involved in DEX’s protection in diabetic rodent myocardial I/R models, including PI3K/Akt and associated GSK-3β pathway stimulation, endoplasmic reticulum stress (ERS) alleviation, and apoptosis inhibition. In addition, DEX could attenuate diabetic myocardial I/R injury by up-regulating autophagy, reducing ROS production, and inhibiting the inflammatory response through HMGB1 pathways. The regulation of autonomic nervous function also appeared to be involved in the protective mechanisms of DEX. In the present review, the evidence and underlying mechanisms of DEX in ameliorating myocardial I/R injury in diabetes are summarized, and the potential of DEX for the treatment/prevention of myocardial I/R injury in diabetic patients is discussed.

Neuroprotective Effect of Dexmedetomidine against Postoperative Cognitive Decline via NLRP3 Inflammasome Signaling Pathway

Dexmedetomidine (Dex), widely used as a sedative in surgical procedures and intensive care units, induces sympatholytic, anxiolytic, analgesic, and sedative effects. Postoperative cognitive dysfunction (POCD) is routinely observed in postoperative care following surgery and general anesthesia. The NLRP3 inflammasome complex plays a critical role in innate immune response by detecting pathogenic microorganisms and activating pro-inflammatory cytokines. Although there are numerous protective effects of Dex among the neurological diseases, specific mechanisms including NLRP3 inflammasome-mediated neuroinflammation via oxidative stress response in a POCD model are not fully understood. Here, we investigated whether Dex exhibits neurocognitive effects through the NLRP3 inflammasome signaling in a POCD mouse model using a neurobehavioral test and ELISA analysis. We also confirmed the level of oxidative stress-related response in the in vitro system in the POCD model. Furthermore, we evaluated the NLRP3 inflammasome complex by immunoprecipitation analysis. In summary, the results of the present study indicated that Dex showed a neuroprotective effect in the POCD model by reducing oxidative stress response through NLRP3 inflammasome-mediated neuroinflammation.

Dexmedetomidine Inhibits Gasdermin D-Induced Pyroptosis via the PI3K/AKT/GSK3β Pathway to Attenuate Neuroinflammation in Early Brain Injury After Subarachnoid Hemorrhage in Rats

Subarachnoid hemorrhage (SAH) is one kind of life-threatening stroke, which leads to severe brain damage. Pyroptosis plays a critical role in early brain injury (EBI) after SAH. Previous reports suggest that SAH-induced brain edema, cell apoptosis, and neuronal injury could be suppressed by dexmedetomidine (Dex). In this study, we used a rat model of SAH to investigate the effect of Dex on pyroptosis in EBI after SAH and to determine the mechanisms involved. Pyroptosis was found in microglia in EBI after SAH. Dex significantly alleviated microglia pyroptosis via reducing pyroptosis executioner GSDMD and inhibited the release of proinflammatory cytokines induced by SAH. Furthermore, the reduction of GSDMD by Dex was abolished by the PI3K inhibitor LY294002. In conclusion, our data demonstrated that Dex reduces microglia pyroptosis in EBI after SAH via the activation of the PI3K/AKT/GSK3β pathway.

Protective effects of dexmedetomidine in vital organ injury: crucial roles of autophagy

Vital organ injury is one of the leading causes of global deaths. Accumulating studies have demonstrated that dexmedetomidine (DEX) has an outstanding protective effect on multiple organs for its antiinflammatory and antiapoptotic properties, while the underlying molecular mechanism is not clearly understood. Autophagy, an adaptive catabolic process, has been found to play a crucial role in the organ-protective effects of DEX. Herein, we present a first attempt to summarize all the evidence on the proposed roles of autophagy in the action of DEX protecting against vital organ injuries via a comprehensive review. We found that most of the relevant studies (17/24, 71%) demonstrated that the modulation of autophagy was inhibited under the treatment of DEX on vital organ injuries (e.g. brain, heart, kidney, and lung), but several studies suggested that the level of autophagy was dramatically increased after administration of DEX. Albeit not fully elucidated, the underlying mechanisms governing the roles of autophagy involve the antiapoptotic properties, inhibiting inflammatory response, removing damaged mitochondria, and reducing oxidative stress, which might be facilitated by the interaction with multiple associated genes (i.e., hypoxia inducible factor-1α, p62, caspase-3, heat shock 70 kDa protein, and microRNAs) and signaling cascades (i.e., mammalian target of rapamycin, nuclear factor-kappa B, and c-Jun N-terminal kinases pathway). The authors conclude that DEX hints at a promising strategy in the management of vital organ injuries, while autophagy is crucially involved in the protective effect of DEX.

Different modalities of analgesia in open heart surgeries in Mansoura University

Background: Opioid usage in cardiac surgery is considered to be the corner stone in management. Inadequate pain control after cardiac surgery complicates patient recovery and increases the load on healthcare services. Multimodal analgesia can be used to achieve better analgesic effect and improves patient outcome.  Material and methods: A total of 90 patients undergoing cardiac surgery with median sternotomy were randomly allocated equally into three groups intraoperatively where first group received continuous infusion of high dose opioids, second group received boluses of low dose opioids and third group received multimodal non opioid analgesics including dexmedetomidine, ketamine and magnesium sulphate. All patients received the same post-operative analgesic regimen consists of morphine patient controlled analgesia (PCA). Results: Patients in multimodal non opioid group had more stable hemodynamics intra and postoperatively. Also, patients in multimodal group had lower pain scores extubation, earlier extubation, shorter ICU stay, earlier mobilization and earlier return of bowel movements compared to patients of both groups received intraoperative higher opioid doses.

A single nucleotide polymorphism-based formula to predict the risk of propofol TCI concentration being over 4 µg mL-1 at the time of loss of consciousness

We aim to develop a formula based on single nucleotide polymorphisms (SNPs) to predict whether the propofol target-controlled infusion (TCI) concentration would be over 4 μg mL^-1 at the time of loss of consciousness (LOC). We recruited 184 patients undergoing thyroid or breast surgeries with propofol anaesthesia. A total of 48 SNPs of CYP2B6, CYP2C9, UGT1A9, HNF4A, ABCB1, ABCC4, ABCG2, GABRA2, GABRA4, GABRB1, GABRB3, GABRG2, GABBR2, GAD1, SLC1A3, BDNF, and NRXN1, previously associated with propofol metabolic and pharmacology pathway, were genotyped. The formula was developed in the training cohort using the least absolute shrinkage and selection operator logistic regression model, and then validated in the testing cohort. The SNPs, GABBR2 rs1167768, GABBR2 rs1571927, NRXN1 rs601010, BDNF rs2049046, GABRA4 rs1512135, UGT1A9 rs11692021, GABBR2 rs2808536, HNF4A rs1884613, GABRB3 rs2017247, and CYP2B6 rs3181842 were selected to construct the SNP-based formula, which was used to calculate the risk score for over 4 μg mL^-1 TCI concentration of propofol at the time of LOC. Patients in the high-risk group were more likely to require a propofol concentration higher than 4 μg mL^-1 and presented a longer LOC latency. The SNP-based formula may significantly improve the safety and effectiveness of propofol-induced anaesthesia.

Effect of dexmedetomidine and propofol sedation on the prognosis of children with severe respiratory failure: a systematic review and meta-analysis

BACKGROUND

During treatment of acute respiratory failure (ARF) in children, sedation can reduce pain, improve tolerance, and reduce the incidence of adverse events, so selecting an appropriate sedation strategy is very important for improving prognosis and quality of life. Both dexmedetomidine and propofol have good sedative effects, so we investigated the application of these drugs in critically ill children with ARF by literature search and meta-analysis.

METHODS

We searched Embase, The Cochrane Library, PubMed, Ovid, Clinicaltrials.org, and Google Scholar for randomized controlled trials (RCTs) preferentially but not exclusively, and used RevMan 5.4 to analyze the screened literature.

RESULTS

Seven studies were included in the quantitative meta-analysis, with a total of 1,188 patients. There was no significant difference in the effect of dexmedetomidine and propofol on the duration of tracheal intubation in children with ARF [mean difference (MD) =-0.05; 95% confidence interval (CI): (-0.42, 0.32); Z=0.26; P=0.79], but dexmedetomidine sedation could reduce the intensive care unit (ICU) stay in children with ARF [MD =-0.62; 95% CI: (-1.08, -0.16); Z=2.65; P=0.008], and shorten the total hospital stay [MD =-1.94; 95% CI: (-2.63, -1.25); Z=5.48; P<0.00001]. There was no significant effect on mortality between the two groups [odds ratio (OR) =0.48; 95% CI: (0.19, 1.25); Z=1.50; P=0.13]. The incidence rate of bradycardia with dexmedetomidine sedation was higher than with propofol [OR =12.30; 95% CI: (2.28, 66.47); Z=2.92; P=0.004], and the incidence of hypotension was also higher [OR =6.99, 95% CI: (1.22, 39.86); Z=2.19; P=0.03].

DISCUSSION

Compared with propofol, dexmedetomidine can significantly reduce the ICU stay and hospital stay. However, bradycardia and hypotension may occur during the use of dexmedetomidine, which requires close attention and timely intervention.

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

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

Anesthetic Management of a Patient Undergoing Cochlear Implantation With Superficial Cervical Plexus Block and Sedation: A Case Report

Avoidance of general anesthesia and endotracheal intubation has been shown to reduce respiratory complications in patients with severe lung disease. We describe the case of a 75-year-old patient with chronic obstructive pulmonary disease (COPD) who underwent cochlear implantation managed with nerve block and sedation. A superficial cervical plexus block (SCPB) was performed with 1% mepivacaine before surgery. A small amount of intravenous analgesic and sedative was administered. The patient experienced only slight pain during surgery. A SCPB had a good analgesic effect on the posterior auricle. Cochlear implantation in patients with COPD can be performed using a SCPB and sedation.

The effectiveness of dexmedetomidine in patients with severe COVID-19

Background: Mortality in patients with severe COVID-19 remains high. Finding therapies that can improve the outcome in these patients is an urgent task. Aims: To evaluate the clinical efficacy of dexmedetomidine in the complex treatment of patients with a severe course of COVID-19. Methods: The retrospective study included 50 adult patients with severe COVID-19 admitted to the intensive care unit (ICU). The primary outcome of the study was the incidence of delirium. The secondary results of the study were the dynamics of gas exchange indicators (PaO2 and PaCO2) and inflammatory markers (C-reactive protein, CRP; procalcitonin, lymphocyte count, and neutrophil-lymphocyte ratio, NLR) on day 3 and day 5 of the treatment, as well as the duration of mechanical ventilation (MV), length of stay (LOS) in the ICU and in the hospital and mortality. Results: The incidence of delirium did not differ between the dexmedetomidine group and the control group (41 and 48%, respectively; p=0.661). The LOS in the ICU and in the hospital, as well as the MV duration, was comparable between the groups. However, the hospital mortality in the dexmedetomidine treatment group was lower than that in the control group (10.3% and 42.9%, respectively; p=0.008). The addition of dexmedetomidine to the therapy complex did not affect the blood gas composition but contributed to the increase in the number of lymphocytes (p=0.006) and to the NLS decrease (p=0.002) by the fifth day of treatment. At the same time, no significant changes in the CRP and procalcitonin levels were observed. Conclusion: In the treatment group, the mortality was statistically significantly lower than it was in the control group. At the same time, the use of dexmedetomidine did not reduce the incidence of delirium, the length of stay in the ICU and in the hospital, and the duration of mechanical ventilation in patients with severe COVID-19. The revealed relationship between the use of dexmedetomidine and NLR and the number of lymphocytes suggests an immune-mediated effect on the outcome in this category of patients. Prospective randomized trials are needed to confirm the beneficial effects of dexmedetomidine on the immune system and mortality.

Safe electrophysiologic profile of dexmedetomidine in different experimental arrhythmia models

Previous studies suggest an impact of dexmedetomidine on cardiac electrophysiology. However, experimental data is sparse. Therefore, purpose of this study was to investigate the influence of dexmedetomidine on different experimental models of proarrhythmia. 50 rabbit hearts were explanted and retrogradely perfused. The first group (n = 12) was treated with dexmedetomidine in ascending concentrations (3, 5 and 10 µM). Dexmedetomidine did not substantially alter action potential duration (APD) but reduced spatial dispersion of repolarization (SDR) and rendered the action potentials rectangular, resulting in no proarrhythmia. In further 12 hearts, erythromycin (300 µM) was administered to simulate long-QT-syndrome-2 (LQT2). Additional treatment with dexmedetomidine reduced SDR, thereby suppressing torsade de pointes. In the third group (n = 14), 0.5 µM veratridine was added to reduce the repolarization reserve. Further administration of dexmedetomidine did not influence APD, SDR or the occurrence of arrhythmias. In the last group (n = 12), a combination of acetylcholine (1 µM) and isoproterenol (1 µM) was used to facilitate atrial fibrillation. Additional treatment with dexmedetomidine prolonged the atrial APD but did not reduce AF episodes. In this study, dexmedetomidine did not significantly alter cardiac repolarization duration and was not proarrhythmic in different models of ventricular and atrial arrhythmias. Of note, dexmedetomidine might be antiarrhythmic in acquired LQT2 by reducing SDR.

Dexmedetomidine protects the heart against ischemia reperfusion injury via regulation of the bradykinin receptors

BACKGROUND

Dexmedetomidine (DEX) has been reported to protect the heart against ischemia reperfusion (I/R) injury. However, the exact mechanisms are still not fully understood.

METHODS AND RESULTS

A rat cardiac I/R injury model was induced by ligation of the left anterior descending coronary artery for 1 h and subsequent reperfusion for 2 h, and DEX was administered intravenously 30 min before ischemia. We confirmed that DEX treatment mitigated cardiac I/R injury. Interestingly, we found that DEX regulated the expression of bradykinin (BK) receptors (B1R and B2R) in rat hearts during I/R injury and enhanced the protective action of BK administered during reperfusion. Moreover, in vitro hypoxia reoxygenation (H/R) injury was induced in neonatal rat cardiomyocytes (CMs), and DEX was administered 1 h before hypoxia. The in vitro findings were consistent with the in vivo experiments. We found that an α2-adrenoceptor (α2-AR) antagonist (yohimbine) completely aborted DEX-induced B1R and B2R regulation; an adenylyl cyclase (AC) agonist (forskolin) blocked B1R downregulation, while a phosphatidylinositol 3-kinase (PI3K) inhibitor (LY294002) blocked B2R upregulation. The above findings indicated that DEX interacted with α2-AR in cardiomyocytes, inhibited B1R expression via suppression of AC, and stimulated B2R expression via activation of PI3K.

CONCLUSIONS

DEX regulates BK receptor expression and potentiates the protection of BK in cardiac I/R injury, which suggests that modulating endogenous cardioprotective factors may play an important role in DEX-induced cardioprotection.

Comparison of Dexmedetomidine and Etomidate on Intraoperative Wake-Up Equality, Hemodynamics, and Cerebral Protection in Operation of the Brain Functional Area

In recent years, with the increasing incidence of brain functional area tumors, the clinical application of functional area tumor resection has become extremely urgent. Intraoperative wake-up is an important auxiliary method of this operation, which can effectively reduce the damage of the brain function area caused by the operation and anesthesia itself while playing the role of auxiliary function area and tumor positioning. However, the intraoperative wake-up requires a higher anesthesia effect, so higher requirements are put forward for the choice of anesthetic drugs. Based on hemodynamic and serum molecular observations, this study found that dexmedetomidine- and etomidate-assisted anesthesia were used for intraoperative wake-up in brain functional area surgery, both of which could maintain hemodynamic stability. In addition, the arousal effect and brain protection of dexmedetomidine were better than those of etomidate, and the incidence of adverse reactions was lower during the arousal period. This can provide relevant reference for clinical improvement of the anesthesia effect and surgical safety of intraoperative wake-up.

Dexmedetomidine does not compromise neuronal viability, synaptic connectivity, learning and memory in a rodent model

Recent animal studies have drawn concerns regarding most commonly used anesthetics and their long-term cytotoxic effects, specifically on the nervous tissue. It is therefore imperative that the search continues for agents that are non-toxic at both the cellular and behavioural level. One such agent appears to be dexmedetomidine (DEX) which has not only been found to be less neurotoxic but has also been shown to protect neurons from cytotoxicity induced by other anesthetic agents. However, DEX's effects on the growth and synaptic connectivity at the individual neuronal level, and the underlying mechanisms have not yet been fully resolved. Here, we tested DEX for its impact on neuronal growth, synapse formation (in vitro) and learning and memory in a rodent model. Rat cortical neurons were exposed to a range of clinically relevant DEX concentrations (0.05-10 µM) and cellular viability, neurite outgrowth, synaptic assembly and mitochondrial morphology were assessed. We discovered that DEX did not affect neuronal viability when used below 10 µM, whereas significant cell death was noted at higher concentrations. Interestingly, in the presence of DEX, neurons exhibited more neurite branching, albeit with no differences in corresponding synaptic puncta formation. When rat pups were injected subcutaneously with DEX 25 µg/kg on postnatal day 7 and again on postnatal day 8, we discovered that this agent did not affect hippocampal-dependent memory in freely behaving animals. Our data demonstrates, for the first time, the non-neurotoxic nature of DEX both in vitro and in vivo in an animal model providing support for its utility as a safer anesthetic agent. Moreover, this study provides the first direct evidence that although DEX is growth permissive, causes mitochondrial fusion and reduces oxygen reactive species production, it does not affect the total number of synaptic connections between the cortical neurons in vitro.

Efficacy of Dexmedetomidine Infusion Without Loading Dose on Hemodynamic Variables and Recovery Time During Craniotomy: A Randomized Double-blinded Controlled Study

Background

Maintaining hemodynamic stability during intracranial surgery is one of the most important tasks. There is no general agreement regarding which anesthetics are optimal for craniotomy. Propofol and short-acting opioids are usually used, but their use is not without side effects. Recently, dexmedetomidine has been considered a safe alternative in different surgeries.

Objectives

We aimed to assess the efficacy of 0.5 µg/kg/h dexmedetomidine infusion without loading dose as an adjunct to general anesthesia for craniotomy.

Methods

A prospective, randomized, double-blinded, parallel-group, placebo-controlled trial was conducted. Setting: Single university teaching hospital’s operating rooms and postoperative intensive care unit. Patients: A total of 50 patients scheduled for elective supratentorial craniotomy participated in this study. Interventions: Patients were randomly divided into either control group (group C) and Dexmedetomidine group (group D). Main outcome measure: Intraoperative hemodynamics measurements at specific timings.

Results

We found that dexmedetomidine had significantly maintained mean arterial blood pressure and heart rate (P-value < 0.001); with lower intraoperative fentanyl and propofol consumption in group D (132 ± 35 µg and 14 ± 30 mg, respectively) when compared to group C (260 ± 38 µg and 534 ± 66 mg, respectively). Finally, a lesser sedation level was noticed in the dexmedetomidine group, together with a significantly lesser recovery time of 10.3 ± 4 min.

Conclusions

Dexmedetomidine infusion without loading dose could be an efficacious and safe agent in achieving hemodynamic stability with intraoperative opioid-sparing effect and lesser recovery time.

Pharmacological Conditioning of the Heart: An Update on Experimental Developments and Clinical Implications

The aim of pharmacological conditioning is to protect the heart against myocardial ischemia-reperfusion (I/R) injury and its consequences. There is extensive literature that reports a multitude of different cardioprotective signaling molecules and mechanisms in diverse experimental protocols. Several pharmacological agents have been evaluated in terms of myocardial I/R injury. While results from experimental studies are immensely encouraging, translation into the clinical setting remains unsatisfactory. This narrative review wants to focus on two aspects: (1) give a comprehensive update on new developments of pharmacological conditioning in the experimental setting concentrating on recent literature of the last two years and (2) briefly summarize clinical evidence of these cardioprotective substances in the perioperative setting highlighting their clinical implications. By directly opposing each pharmacological agent regarding its recent experimental knowledge and most important available clinical data, a clear overview is given demonstrating the remaining gap between basic research and clinical practice. Finally, future perspectives are given on how we might overcome the limited translatability in the field of pharmacological conditioning.

[Perioperative cardioprotection - From bench to bedside : Current experimental evidence and possible reasons for the limited translation into the clinical setting]

Hintergrund

Ziel der perioperativen Kardioprotektion ist es, die Auswirkungen eines Ischämie- und Reperfusionsschadens zu minimieren. Aus anästhesiologischer Sicht spielt dieser Aspekt insbesondere in der Herzchirurgie bei Patienten mit Einsatz der Herz-Lungen-Maschine, aber auch allgemein bei längerfristigen hypotensiven Phasen oder perioperativen ischämischen Ereignissen im nichtkardiochirurgischen Setting eine wichtige Rolle. Im Laufe der letzten Jahre konnten diverse pharmakologische sowie nichtpharmakologische Strategien der Kardioprotektion identifiziert werden. Die Ergebnisse von Studien an isoliertem Gewebe sowie von tierexperimentellen In-vivo-Studien sind vielversprechend. Eine Translation dieser kardioprotektiven Strategien in die klinische Praxis ist bislang jedoch nicht gelungen. Große klinische Studien konnten keine signifikante Verbesserung des Outcome der Patienten zeigen.

Ziel der Arbeit

Dieser Übersichtsartikel gibt einen Überblick über die aktuelle experimentelle Evidenz pharmakologischer und nichtpharmakologischer Kardioprotektion. Außerdem sollen mögliche Gründe für die limitierte Translation diskutiert werden. Schließlich werden Möglichkeiten aufgezeigt, wie der Schritt „from bench to bedside“ in Zukunft doch noch gelingen könnte.

Material und Methoden

Narrative Übersichtsarbeit.

Ergebnisse und Diskussion

Trotz der vielversprechenden präklinischen experimentellen Ansätze zum Thema Kardioprotektion besteht nach wie vor eine große Diskrepanz zu den Ergebnissen aus großen klinischen Studien in der perioperativen Phase. Mögliche Gründe für die limitierte Translation könnten insbesondere Komorbiditäten und Komedikationen, die Wahl des Anästhesieverfahrens, aber auch die Wahl des Studiendesigns sein. Eine sorgfältige Studienplanung mit Berücksichtigung der genannten Probleme sowie ein simultaner Einsatz mehrerer kardioprotektiver Strategien mit dem Ziel eines additiven bzw. synergistischen Effekts stellen mögliche Ansätze für die Zukunft dar.

Perioperative Cardioprotection: General Mechanisms and Pharmacological Approaches

Cardioprotection encompasses a variety of strategies protecting the heart against myocardial injury that occurs during and after inadequate blood supply to the heart during myocardial infarction. While restoring reperfusion is crucial for salvaging myocardium from further damage, paradoxically, it itself accounts for additional cell death-a phenomenon named ischemia/reperfusion injury. Therefore, therapeutic strategies are necessary to render the heart protected against myocardial infarction. Ischemic pre- and postconditioning, by short periods of sublethal cardiac ischemia and reperfusion, are still the strongest mechanisms to achieve cardioprotection. However, it is highly impractical and far too invasive for clinical use. Fortunately, it can be mimicked pharmacologically, for example, by volatile anesthetics, noble gases, opioids, propofol, dexmedetomidine, and phosphodiesterase inhibitors. These substances are all routinely used in the clinical setting and seem promising candidates for successful translation of cardioprotection from experimental protocols to clinical trials. This review presents the fundamental mechanisms of conditioning strategies and provides an overview of the most recent and relevant findings on different concepts achieving cardioprotection in the experimental setting, specifically emphasizing pharmacological approaches in the perioperative context.

Dexmedetomidine for early postoperative cognitive dysfunction after video-assisted thoracoscopic lobectomy in elderly male patients with lung cancer

This retrospective study explored the efficacy and safety of dexmedetomidine in treating early postoperative cognitive dysfunction (EPPNCD) after video-assisted thoracoscopic lobectomy (VATL) in elderly male patients with lung cancer (LC).This study included a total of 80 elderly male patients with LC who received VATL. All of them were equally assigned to a treatment group and a control group, with 40 patients each group. The primary outcome included cognitive dysfunction, as evaluated by mini-mental state examination scale. The secondary outcomes consisted of incidence of EPPNCD, lung function (as measured by forced vital capacity, forced expiratory volume in 1 second, peak expiratory flow, and maximal voluntary ventilation), and adverse events. All outcome data were analyzed before and 3 days after surgery.After surgery, all patients in the treatment group exerted better efficacy in mini-mental state examination scale (P < .01) and incidence of EPPNCD (P = .03), than patients in the control group. However, no significant differences were detected in forced vital capacity (P = .65), forced expiratory volume in 1 second (P = .50), peak expiratory flow (P = .73), and maximal voluntary ventilation (P = .27) between 2 groups. In addition, there is similar safety profile between 2 groups.The findings of this study showed that dexmedetomidine may benefit EPPNCD after VATL in elderly male patients with LC. Future studies are needed to warrant the present conclusions.