The Role of the α2-Adrenoceptor Agonist Dexmedetomidine in Postsurgical Sedation in the Intensive Care Unit

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.

Practice-Pattern Variation in Sedation of Neurotrauma Patients in the Intensive Care Unit: An International Survey

Background: Analgo-sedation plays an important role during intensive care management of traumatic brain injury (TBI) patients, however, limited evidence is available to guide practice. We sought to quantify practice-pattern variation in neurotrauma sedation management, surveying an international sample of providers. Methods: An electronic survey consisting of 56 questions was distributed internationally to neurocritical care providers utilizing the Research Electronic Data Capture platform. Descriptive statistics were used to quantitatively describe and summarize the responses. Results: Ninety-five providers from 37 countries responded. 56.8% were attending physicians with primary medical training most commonly in intensive care medicine (68.4%) and anesthesiology (26.3%). Institutional sedation guidelines for TBI patients were available in 43.2%. Most common sedative agents for induction and maintenance, respectively, were propofol (87.5% and 88.4%), opioids (60.2% and 70.5%), and benzodiazepines (53.4% and 68.4%). Induction and maintenance sedatives, respectively, are mostly chosen according to provider preference (68.2% and 58.9%) rather than institutional guidelines (26.1% and 35.8%). Sedation duration for patients with intracranial hypertension ranged from 24 h to 14 days. Neurological wake-up testing (NWT) was routinely performed in 70.5%. The most common NWT frequency was every 24 h (47.8%), although 20.8% performed NWT at least every 2 h. Richmond Agitation and Sedation Scale targets varied from deep sedation (34.7%) to alert and calm (17.9%). Conclusions: Among critically ill TBI patients, sedation management follows provider preference rather than institutional sedation guidelines. Wide practice-pattern variation exists for the type, duration, and target of sedative management and NWT performance. Future comparative effectiveness research investigating these differences may help optimize sedation strategies to promote recovery.

Efficacy, safety, and pharmacokinetics of MR13A11A, a generic of remifentanil, for pain management of Japanese patients in the intensive care unit: a double-blinded, fentanyl-controlled, randomized, non-inferiority phase 3 study

BACKGROUND

The aims of this study were to evaluate the efficacy, safety, and pharmacokinetics (PK) of continuous intravenous administration of remifentanil in mechanically ventilated patients in the intensive care unit (ICU).

METHODS

This was a multicenter, randomized, double-blinded, fentanyl-controlled, non-inferiority phase 3 study. Patients aged ≥ 20 years requiring 6 h to 10 days mechanical ventilation in an ICU and requiring pain relief were randomly assigned in a 1:1 ratio to receive either remifentanil (n = 98) or fentanyl (n = 98). Dose was titrated from an infusion rate of 1 mL/h (remifentanil: 0.025 µg/kg/min, fentanyl: 0.1 µg/kg/h) until the target level of analgesia (behavioral pain scale [BPS] ≤ 5 or numerical rating score [NRS] ≤ 3) was achieved by escalating the dose in 1 mL/h increasing. Administration was then adjusted to maintain the target level of analgesia until weaning from the ventilator. The primary endpoint was the proportion of patients who did not require rescue fentanyl. Safety was assessed according to standard procedures. PK of remifentanil in the arterial blood was assessed in 24 patients.

RESULTS

The proportion of patients achieving the primary endpoint in the remifentanil and fentanyl groups was 100% (92/92) and 97.8% (88/90), respectively. The difference between the groups was 2.2% (95% confidence interval, - 0.8-5.3) and non-inferiority of remifentanil to fentanyl was verified (p < 0.0001). The incidences of any adverse events in the remifentanil and fentanyl groups was 34 of 92 patients (37.0%) and 34 of 90 patients (37.8%), respectively. Adverse drug reactions was 12 in 92 patients (13.0%) and 15 in 90 patients (16.7%), respectively. In the PK analysis, blood remifentanil concentration decreased within 10 min to almost 50% of the end of administration, suggesting rapid offset of action following discontinuation of remifentanil.

CONCLUSIONS

Remifentanil can be used safely for pain management in mechanically ventilated Japanese patients in the ICU.

TRIAL REGISTRATION

Japan Registry of Clinical Trials, jRCT2080224954. Registered 20 November 2019, https://jrct.niph.go.jp/latest-detail/jRCT2080224954 .

Transversus abdominis plane block versus caudal block with bupivacaine and dexmedetomidine for unilateral inguinal hernia repair in pediatric patients: a randomized clinical trial

BACKGROUND

This study compared the transversus abdominis plane (TAP) block with bupivacaine and dexmedetomidine to the same mixture in the caudal block in delivering postoperative analgesia in children after unilateral inguinal hernia surgery.

METHODS

The current study included 80 children aged two to eight years who were scheduled for unilateral inguinal hernia surgery under general anesthesia. A caudal block (1 mL/kg 0.25% bupivacaine and one µg /kg dexmedetomidine) or a TAP block (1 mL/kg 0.25% bupivacaine and one µg /kg dexmedetomidine) was given to each participant at random. The time it took to request analgesia for the first time, the postoperative pain score, total analgesic use, sedation, family satisfaction, and side effects were all measured. The primary outcome was time to first analgesic request.

RESULTS

The caudal block group had a considerably shorter time to first analgesic request than the TAP block group. The caudal block group received more rescue analgesia doses within 24 hours than the TAP block group. The mean total dose of intravenous paracetamol within the first 24 hours postoperatively was greater in the caudal block group. The caudal block group had much higher family satisfaction.

CONCLUSIONS

The TAP block and caudal block provide good postoperative analgesia in children undergoing unilateral inguinal hernia repair. Adding dexmedetomidine to the TAP block was superior to the caudal block in terms of extending the length of the initial analgesic request, lowering analgesic requirement, and lowering pain scores without causing substantial adverse effects.

Modulating Hyperpolarization-Activated Cation Currents through Small Molecule Perturbations: Magnitude and Gating Control

The hyperpolarization-activated cation current (Ih) exhibits a slowly activating time course of the current (Ih) when the cell membrane is hyperpolarized for an extended duration. It is involved in generating electrical activity in various excitable cells. Numerous structurally distinct compounds or herbal drugs have the potential to impact both the magnitude and gating kinetics of this current. Brivaracetam, a chemical analog of levetiracetam known to be a ligand for synaptic vesicle protein 2A, could directly suppress the Ih magnitude. Carisbamate, an anticonvulsant agent, not only inhibited the Ih amplitude but also reduced the strength of voltage-dependent hysteresis (Hys(V)) associated with Ih. Cilobradine, similar to ivabradine, inhibited the amplitude of Ih; however, it also suppressed the amplitude of delayed-rectifier K+ currents. Dexmedetomidine, an agonist of α2-adrenergic receptor, exerted a depressant action on Ih in a concentration-dependent fashion. Suppression of Ih amplitude was observed when GAL-021, a breathing control modulator, was present at a concentration exceeding 30 μM. Lutein, one of the few xanthophyll carotenoids, was able to suppress the Ih amplitude as well as to depress Hys(V)'s strength of Ih. Pirfenidone, a pyridine derivative known to be an anti-fibrotic agent, depressed the Ih magnitude in a concentration- and voltage-dependent fashion. Tramadol, a synthetic centrally active analgesic, was shown to reduce the Ih magnitude, independent of its interaction with opioid receptors. Various herbal drugs, including ent-kaurane-type diterpenoids from Croton tonkinensis, Ganoderma triterpenoids, honokiol, and pterostilbene, demonstrated efficacy in reducing the magnitude of Ih. Conversely, oxaliplatin, a platinum-based chemotherapeutic compound, was observed to effectively increase the Ih amplitude. Collectively, the regulatory effects of these compounds or herbal drugs on cellular function can be partly attributed to their perturbations on Ih.

Dexmedetomidine for the prevention of delirium in adults admitted to the intensive care unit or post-operative care unit: A systematic review of randomised clinical trials with meta-analysis and Trial Sequential Analysis

OBJECTIVES

To assess any benefit or harm, we conducted a systematic review of randomised clinical trials (RCTs) allocating adults to dexmedetomidine versus placebo/no intervention for the prevention of delirium in intensive care or post-operative care units.

DATA SOURCES

We searched Medline, Embase, CENTRAL and other databases. The last search was 9 April 2022.

DATA EXTRACTION

Literature screening, data extraction and risk of bias volume 2 assessments were performed independently and in duplicate. Primary outcomes were occurrences of serious adverse events (SAEs), delirium and all-cause mortality. We used meta-analysis, Trial Sequential Analysis, and GRADE (Grading Recommendations Assessment, Development and Evaluation).

DATA SYNTHESIS

Eighty-one RCTs (15,745 patients) provided data for our primary outcomes. Results from trials at low risk of bias showed that dexmedetomidine may reduce the occurrence of the most frequently reported SAEs (relative risk [RR] 0.69; 95% CI 0.43-1.09), cumulated SAEs (RR 0.70; 95% CI 0.52-0.95) and the occurrence of delirium (RR 0.62; 95% CI 0.43-0.89). The certainty of evidence was very low for delirium. Mortality was very low in trials at low risk of bias (0.4% in the dexmedetomidine groups and 1.0% in the control groups) and meta-analysis did not provide conclusive evidence that dexmedetomidine may result in lower or higher all-cause mortality (RR 0.47; 95% CI 0.18-1.21). There was a lack of information from trial results at low risk of bias for all primary outcomes.

CONCLUSIONS

Trial results at low risk of bias showed that dexmedetomidine might reduce occurrences of SAEs and delirium, while no conclusive evidence was found for effects on all-cause mortality. The certainty of evidence ranged from very low for occurrence of delirium to low for the remaining outcomes.

Effective Perturbations by Small-Molecule Modulators on Voltage-Dependent Hysteresis of Transmembrane Ionic Currents

The non-linear voltage-dependent hysteresis (Hys_(V)) of voltage-gated ionic currents can be robustly activated by the isosceles-triangular ramp voltage (V_ramp) through digital-to-analog conversion. Perturbations on this Hys_(V) behavior play a role in regulating membrane excitability in different excitable cells. A variety of small molecules may influence the strength of Hys_(V) in different types of ionic currents elicited by long-lasting triangular V_ramp. Pirfenidone, an anti-fibrotic drug, decreased the magnitude of I_h's Hys_(V) activated by triangular V_ramp, while dexmedetomidine, an agonist of α₂-adrenoceptors, effectively suppressed I_h as well as diminished the Hys_(V) strength of I_h. Oxaliplatin, a platinum-based anti-neoplastic drug, was noted to enhance the I_h's Hys_(V) strength, which is thought to be linked to the occurrence of neuropathic pain, while honokiol, a hydroxylated biphenyl compound, decreased I_h's Hys_(V). Cell exposure to lutein, a xanthophyll carotenoid, resulted in a reduction of I_h's Hys_(V) magnitude. Moreover, with cell exposure to UCL-2077, SM-102, isoplumbagin, or plumbagin, the Hys_(V) strength of erg-mediated K⁺ current activated by triangular V_ramp was effectively diminished, whereas the presence of either remdesivir or QO-58 respectively decreased or increased Hys_(V) magnitude of M-type K⁺ current. Zingerone, a methoxyphenol, was found to attenuate Hys_(V) (with low- and high-threshold loops) of L-type Ca²⁺ current induced by long-lasting triangular V_ramp. The Hys_(V) properties of persistent Na⁺ current (I_Na(P)) evoked by triangular V_ramp were characterized by a figure-of-eight (i.e., ∞) configuration with two distinct loops (i.e., low- and high-threshold loops). The presence of either tefluthrin, a pyrethroid insecticide, or t-butyl hydroperoxide, an oxidant, enhanced the Hys_(V) strength of I_Na(P). However, further addition of dapagliflozin can reverse their augmenting effects in the Hys_(V) magnitude of the current. Furthermore, the addition of esaxerenone, mirogabalin, or dapagliflozin was effective in inhibiting the strength of I_Na(P). Taken together, the observed perturbations by these small-molecule modulators on Hys_(V) strength in different types of ionic currents evoked during triangular V_ramp are expected to influence the functional activities (e.g., electrical behaviors) of different excitable cells in vitro or in vivo.

Dexmedetomidine vs other sedatives in critically ill mechanically ventilated adults: a systematic review and meta-analysis of randomized trials

Conventional gabaminergic sedatives such as benzodiazepines and propofol are commonly used in mechanically ventilated patients in the intensive care unit (ICU). Dexmedetomidine is an alternative sedative that may achieve lighter sedation, reduce delirium, and provide analgesia. Our objective was to perform a comprehensive systematic review summarizing the large body of evidence, determining if dexmedetomidine reduces delirium compared to conventional sedatives. We searched MEDLINE, EMBASE, CENTRAL, ClinicalTrials.gov and the WHO ICTRP from inception to October 2021. Independent pairs of reviewers identified randomized clinical trials comparing dexmedetomidine to other sedatives for mechanically ventilated adults in the ICU. We conducted meta-analyses using random-effects models. The results were reported as relative risks (RRs) for binary outcomes and mean differences (MDs) for continuous outcomes, with corresponding 95% confidence intervals (CIs). In total, 77 randomized trials (n = 11,997) were included. Compared to other sedatives, dexmedetomidine reduced the risk of delirium (RR 0.67, 95% CI 0.55 to 0.81; moderate certainty), the duration of mechanical ventilation (MD - 1.8 h, 95% CI  - 2.89 to  - 0.71; low certainty), and ICU length of stay (MD  - 0.32 days, 95% CI  - 0.42 to  - 0.22; low certainty). Dexmedetomidine use increased the risk of bradycardia (RR 2.39, 95% CI 1.82 to 3.13; moderate certainty) and hypotension (RR 1.32, 95% CI 1.07 to 1.63; low certainty). In mechanically ventilated adults, the use of dexmedetomidine compared to other sedatives, resulted in a lower risk of delirium, and a modest reduction in duration of mechanical ventilation and ICU stay, but increased the risks of bradycardia and hypotension.

Tasipimidine-the pharmacological profile of a novel orally active selective α2A-adrenoceptor agonist

The pharmacological profile of tasipimidine, a novel orally active α₂-adrenoceptor agonist developed for situational anxiety and fear in dogs, was studied in various in vitro and in vivo models. In the cell assays, tasipimidine demonstrated binding affinity and full agonism on the human α_2A-adrenoceptors with a pEC50 of 7.57, while agonism on the α_2B-and α_2C-adrenoceptors and the rodent α_2D-adrenoceptor was weaker, resulting in pEC50 values of 6.00, 6.29 and 6.56, respectively. Tasipimidine had a low binding affinity on the human α₁-adrenoceptors. It had no functional effects in the LNCaP cells expressing endogenously the human α_1A-adrenoceptors but was a weak agonist in the Chem-1 cells coexpressing Gα15 protein and α_1A-adrenoceptors. In the recombinant CHO cells, although tasipimidine was a weak partial agonist in the inositol monophosphate accumulation assay, it was a full agonist in the intracellular [Ca²⁺] assay. No functional effects were observed on the human α_1B-adrenoceptor, whereas in the rat α_1A and α_1B-adrenoceptors, tasipimidine was a weak partial agonist. In the rat vas deferens preparations, tasipimidine was a full agonist on the α_2D-adrenoceptor but weak partial agonist on the α₁-adrenoceptor. The receptor profile of tasipimidine indicated few secondary targets, and no functional effects were observed. Sedative effects of tasipimidine were demonstrated in vivo by the reduced acoustic startle reflex in rats with subcutaneous doses and decreased spontaneous locomotor activity in mice with subcutaneous and higher oral doses. It may be concluded that tasipimidine is an orally active and selective α_2A-adrenoceptor agonist.

Effect of Dexmedetomidine on Tachyarrhythmias After Cardiac Surgery: A Systematic Review and Meta-Analysis

ABSTRACT

Tachyarrhythmias after cardiac surgery is a common occurrence in clinical practice, which can be life threatening. We searched 6 databases, including Embase, PubMed, Cochrane, CNKI, Wanfang, and Sinomed, to evaluate the effect of dexmedetomidine on tachyarrhythmias after adult cardiac surgery. The primary end point was the number of patients with atrial fibrillation (AF) after cardiac surgery. The secondary end points included the number of patients with supraventricular tachycardia or with ventricular tachycardia or with ventricular fibrillation or with myocardial infarction or deceased patients, the duration of mechanical ventilation, the intensive care unit stay, hospital stay, and the number of patients with bradycardia and those with hypotension. Among the 1388 retrieved studies, 18 studies (n = 3171 participants) met our inclusion criteria. Dexmedetomidine reduced the incidence of AF by 17% [relative risk (RR) = 0.83; 95% confidence interval (CI), 0.73-0.93; P = 0.002]. Through subgroup analysis, we found that when the maintenance dose of dexmedetomidine was >0.7 µg·kg-1·h-1, the effect of preventing AF was obvious (RR = 0.58; 95%CI 0.43-0.78; P = 0.0003). Dexmedetomidine also reduced the incidence of supraventricular tachycardia by approximately 70% (RR = 0.29; 95% CI, 0.11-0.77; P = 0.01) and the incidence of ventricular tachycardia by approximately 80% (RR = 0.23; 95% CI, 0.08-0.63; P = 0.004) but had no effect on ventricular fibrillation (RR = 1.02; 95% CI, 0.14-7.31; P = 0.99). The major side effect of dexmedetomidine was bradycardia. Dexmedetomidine can reduce the incidence of AF (especially high dosages), supraventricular tachycardia, and ventricular tachycardia after cardiac surgery in adults, but it does not affect the occurrence of ventricular fibrillation.

Effects of Intraoperative Dexmedetomidine Infusion on Postoperative Pain after Craniotomy: A Narrative Review

Craniotomy involves procedures with high incidences of postoperative pain. Dexmedetomidine, a highly selective a₂-adrenoreceptor agonist, has been shown to be beneficial in neuroanaesthesia. The purpose of this narrative review was to assess the effect and safety of dexmedetomidine given intraoperatively during anaesthesia compared to placebo and demonstrate the effect on acute postoperative pain in adult patients undergoing craniotomy. Literature published from 1996 until 2021 were analysed through a search of PubMed, Medline and Embase. Randomised controlled trials investigating intraoperative administration of Dexmedetomidine with evaluation of postoperative pain were included. Medical Subject Headings terms and free-text words were used to identify articles related to the intraoperative use of Dexmedetomidine and postcraniotomy pain. Thirteen distinct randomized controlled trials with 882 recruited patients undergoing craniotomy were identified as eligible for final inclusion. Intraoperative administration of dexmedetomidine is associated with decreased postoperative pain and opioid consumption, and it assures haemodynamic stability. Dexmedetomidine is an efficacious adjunct in craniotomy in adults, showing benefits in reduction of postoperative pain and analgesic consumption. Dexmedetomidine also offers haemodynamic stability. However, widespread methodological heterogeneity of the papers prohibits a valid meta-analysis.

Pain Management Considerations in Patients with Opioid Use Disorder Requiring Critical Care

The opioid epidemic has resulted in increased opioid-related critical care admissions, presenting challenges in acute pain management. Limited guidance exists in the management of critically ill patients with opioid use disorder (OUD). This narrative review provides the intensive care unit (ICU) clinician with guidance and treatment options, including non-opioid analgesia, for patients receiving medications for opioid use disorder (MOUD) and for patients actively misusing opioids. Verification and continuation of the patient's outpatient MOUD regimen, specifically buprenorphine and methadone formulations, assessment of pain and opioid withdrawal, and treatment of acute pain with non-opioid analgesia, nonpharmacologic strategies, and short-acting opioids as needed, are all essential to adequate management of acute pain in patients with OUD. A multidisciplinary approach to treatment and discharge planning in patients with OUD may be beneficial to engage patients with OUD early in their hospital stay to prevent withdrawal, stabilize their OUD, and to reduce the risk of unplanned discharge and other associated morbidity. This article is protected by copyright. All rights reserved.

Age-Specific Dose Regimens of Dexmedetomidine for Pediatric Patients in Intensive Care Following Elective Surgery: A Phase 3, Multicenter, Open-Label Clinical Trial in Japan

OBJECTIVES

To demonstrate the efficacy, safety, and pharmacokinetics of dexmedetomidine as a potential sedative for pediatric surgery patients in the ICU.

DESIGN

Phase 3, multicenter, open-label study.

SETTING

This study included 61 patients at 13 tertiary hospitals in Japan.

PATIENTS

Pediatric patients (≥ 45 wk corrected gestational age to < 17 yr) undergoing intensive care treatment with mechanical ventilation requiring greater than 6 hours estimated duration of sedation following elective cardiac surgery.

INTERVENTIONS

Dexmedetomidine was IV administered without a loading dose at age-specific dose regimens 0.2-1.4 (< 6 yr) and 0.2-1.0 µg/kg/hr (≥ 6 yr). The primary endpoint was the percentage of patients who did not require a rescue sedative (midazolam) infusion during mechanical ventilation or for the first 24 hours of a greater than 24 hours ventilation following the commencement of dexmedetomidine administration.

MEASUREMENTS AND MAIN RESULTS

Overall, 47 of the 61 patients (77.0%) did not require rescue midazolam. Adverse events were reported in 53 patients (86.9%). Frequently observed adverse events were hypotension (47.5%), bradycardia (31.1%), and respiratory depression (26.2%). Most of these adverse events were mild, a few moderate, and none severe. Although serious adverse events occurred in four patients, including one cardiac tamponade resulting in the withdrawal of dexmedetomidine, none of the adverse events resulted in mortality or were directly related to dexmedetomidine. The plasma dexmedetomidine concentration generally reached the target concentration of 0.3-1.25 ng/mL at 1-2 hours prior to completion of administration or immediately prior to the commencement of tapering.

CONCLUSIONS

The age-specific dose regimens of dexmedetomidine without an initial loading dose achieved an adequate sedation level during mechanical ventilation and caused no clinically significant adverse events in the intensive care pediatric patients. These effects were achieved within the therapeutic range of dexmedetomidine plasma concentration and were accompanied by minimal effects on hemodynamics and respiration.

Challenges in Sedation Management in Critically Ill Patients with COVID-19: a Brief Review

Purpose of Review

To highlight the challenges associated with providing sedation and analgesia to critically ill patients with coronavirus disease 2019 (COVID-19) and also understand the pathophysiological alterations induced by the disease process as well as the logistical difficulties encountered by providers caring for these patients. We also discuss the rationale and risks associated with the use of common sedative agents specifically within the context of COVID-19 and provide evidence-based management strategies to help manage sedation and analgesia in such patients.

Recent Findings

A significant proportion of patients with COVID-19 require intensive care and mechanical ventilation, thus requiring sedation and analgesia. These patients tend to require higher doses of sedative medications and often for long periods of time. Most of the commonly used sedative and analgesic agents carry unique risks that should be considered within the context of the unique pathophysiology of COVID-19, the logistical issues the disease poses, and the ongoing drug shortages.

Summary

With little attention being paid to sedation practices specific to patients with COVID-19 in critical care literature and minimal mention in national guidelines, there is a significant gap in knowledge. We review the existing literature to discuss the unique challenges that providers face while providing sedation and analgesia to critically ill patients with COVID-19 and propose evidence-based management strategies.

Injection of Lidocaine Alone versus Lidocaine plus Dexmedetomidine in Impacted Third Molar Extraction Surgery, a Double-Blind Randomized Control Trial for Postoperative Pain Evaluation

Objectives

Administration of medications such as dexmedetomidine as a topical anesthetic has been suggested in the pain control in dentistry. This double-blind randomized control trial study evaluated postoperative pain and associated factors following impacted third molar extraction surgery. Lidocaine alone was taken as the control and lidocaine plus dexmedetomidine as the intervention.

Materials and Methods

Forty patients undergoing mandibular third molar extraction entered the study and were randomly allocated to the control and interventional groups. 0.15 ml of dexmedetomidine was added to each lidocaine cartridge and the drug concentration was adjusted to 15 μg for the intervention group while only lidocaine was used in the control group. A visual analog scale was used to measure and record pain levels at the end of the surgery and 6, 12, and 24 hours after the surgery and number of painkillers taken by the patients after the surgery was also recorded.

Results

Pain scores of the intervention group decreased significantly during the surgery and also 6, 12, and 24 hours after the surgery compared to the control group. The pain score was correlated significantly with our intervention during the surgery and also 6 and 12 hours after that (all P value < 0.05). There was a nonsignificant reduction in the number of painkillers taken by the patients at 6, 12, and 24 hours after surgery (all P value > 0.05).

Conclusion

In patients undergoing molar surgery, administration of a combination of dexmedetomidine and lidocaine is beneficial for the pain control. Clinical Relevance. Compared to the injection of lidocaine alone, combination of dexmedetomidine and lidocaine can be used for a better pain control in molar surgeries.

Effect of dexmedetomidine on delirium during sedation in adult patients in intensive care units: A systematic review and meta-analysis

STUDY OBJECTIVE

To compare the effect of sedation protocols with and without dexmedetomidine on delirium risk and duration in adult patients in intensive care units (ICUs).

DESIGN

A meta-analysis of randomized controlled trials.

REVIEW METHODS

We searched the Cochrane Central Register of Controlled Trials, PubMed, EMBASE, and ISI Web of Science from inception to September 3, 2020. We included studies comparing the effect of dexmedetomidine-based sedation on delirium risk with non-dexmedetomidine-based sedation in adult patients in ICUs. We pooled the data using a random-effects model using Review Manager 5.2, and assessed publication bias using Stata 11.0. The quality of evidence was rated using the Grading of Recommendations, Assessment, Development and Evaluation system.

MAIN RESULTS

We included 36 studies involving 9623 participants. The use of dexmedetomidine was associated with reduced risk of delirium (risk ratio [RR], 0.63; 95% confidence interval [CI], 0.54-0.75; very low-quality evidence), but higher incidences of hypotension and bradycardia during hospital stay. Dexmedetomidine was also associated with shorter durations of ICU stay, hospital stay and mechanical ventilation. Dexmedetomidine did not affect ICU mortality (RR, 1.01; 95% CI, 0.89-1.14; low-quality evidence), hospital mortality (RR, 1.01; 95% CI, 0.91-1.12; very low-quality evidence), or 30-day mortality (RR, 0.77; 95% CI, 0.58-1.01; moderate-quality evidence), or duration of delirium (mean difference, -0.74 days; 95% CI, -1.83 to 0.36 days; very low-quality evidence). We identified publication bias for risk and duration of delirium, length of ICU stay, and hospital stay.

CONCLUSIONS

Low- or very low-quality evidence suggests that dexmedetomidine was associated with a clinically-small reduction of delirium risk, ICU/hospital stay and mechanical ventilation duration, but were not associated with improved mortality or shorter delirium duration in ICU patients. These findings were inconclusive because of publication bias, heterogeneity, and limited sample size. Significant adverse effects of dexmedetomidine include hypotension and bradycardia. PROSPERO registration number: CRD42018095358.

Effectiveness in Block by Dexmedetomidine of Hyperpolarization-Activated Cation Current, Independent of Its Agonistic Effect on α2-Adrenergic Receptors

Dexmedetomidine (DEX), a highly selective agonist of α₂-adrenergic receptors, has been tailored for sedation without risk of respiratory depression. Our hypothesis is that DEX produces any direct perturbations on ionic currents (e.g., hyperpolarization-activated cation current, I_h). In this study, addition of DEX to pituitary GH₃ cells caused a time- and concentration-dependent reduction in the amplitude of I_h with an IC₅₀ value of 1.21 μM and a K_D value of 1.97 μM. A hyperpolarizing shift in the activation curve of I_h by 10 mV was observed in the presence of DEX. The voltage-dependent hysteresis of I_h elicited by long-lasting triangular ramp pulse was also dose-dependently reduced during its presence. In continued presence of DEX (1 μM), further addition of OXAL (10 μM) or replacement with high K⁺ could reverse DEX-mediated inhibition of I_h, while subsequent addition of yohimbine (10 μM) did not attenuate the inhibitory effect on I_h amplitude. The addition of 3 μM DEX mildly suppressed the amplitude of erg-mediated K⁺ current. Under current-clamp potential recordings, the exposure to DEX could diminish the firing frequency of spontaneous action potentials. In pheochromocytoma PC12 cells, DEX was effective at suppressing I_h together with a slowing in activation time course of the current. Taken together, findings from this study strongly suggest that during cell exposure to DEX used at clinically relevant concentrations, the DEX-mediated block of I_h appears to be direct and would particularly be one of the ionic mechanisms underlying reduced membrane excitability in the in vivo endocrine or neuroendocrine cells.

American Burn Association Guidelines on the Management of Acute Pain in the Adult Burn Patient: A Review of the Literature, a Compilation of Expert Opinion, and Next Steps

The ABA pain guidelines were developed 14 years ago and have not been revised despite evolution in the practice of burn care. A sub-committee of the American Burn Association's Committee on the Organization and Delivery of Burn Care was created to revise the adult pain guidelines. A MEDLINE search of English-language publications from 1968 to 2018 was conducted using the keywords "burn pain," "treatment," and "assessment." Selected references were also used from the greater pain literature. Studies were graded by two members of the committee using Oxford Centre for Evidence-based Medicine-Levels of Evidence. We then met as a group to determine expert consensus on a variety of topics related to treating pain in burn patients. Finally, we assessed gaps in the current knowledge and determined research questions that would aid in providing better recommendations for optimal pain management of the burn patient. The literature search produced 189 papers, 95 were found to be relevant to the assessment and treatment of burn pain. From the greater pain literature 151 references were included, totaling 246 papers being analyzed. Following this literature review, a meeting to establish expert consensus was held and 20 guidelines established in the areas of pain assessment, opioid medications, nonopioid medications, regional anesthesia, and nonpharmacologic treatments. There is increasing research on pain management modalities, but available studies are inadequate to create a true standard of care. We call for more burn specific research into modalities for burn pain control as well as research on multimodal pain control.

The Pediatric Burn: Current Trends and Future Directions

Management of the pediatric burn patient presents a variety of clinical challenges for the pediatric anesthesiologist. Despite the high incidence of burn injuries, standard management strategies are far from universal. The complex physiologic changes presented by burn injuries present airway management and resuscitation challenges and mandate careful consideration of adequate nutritional support. Long hospital stays with frequent operations and dressing changes necessitate creative approaches to anxiolysis and pain control. Underutilized modalities warranting further research include regional anesthesia and nonpharmacologic approaches, such as virtual reality. Further research and collaboration between burn centers are needed to standardize care for this population.

Adjuvant Analgesic Use in the Critically Ill: A Systematic Review and Meta-Analysis

Supplemental Digital Content is available in the text.

This systematic review and meta-analysis addresses the efficacy and safety of nonopioid adjunctive analgesics for patients in the ICU.

<p>Cost-Minimization Analysis of Dexmedetomidine Compared to Other Sedatives for Short-Term Sedation During Mechanical Ventilation in the United States</p>

Purpose

Mechanical ventilation (MV) remains a substantial cost driver in intensive care units (ICU) in the United States (US). Evaluations of standard sedation treatments used to relieve pain and discomfort in this setting have found varying impacts on ICU length of stay. This cost analysis examines both length-of=stay costs and the total cost implications among MV patients receiving common sedative treatments (dexmedetomidine, propofol, or midazolam) in short-term sedation settings (<24 hours).

Methods

A cost-minimization model was conducted from the hospital provider perspective. Clinical outcomes were obtained from published literature and included ICU length of stay, MV duration, prescription of sedatives and pain medication, and the occurrence of adverse events. Outcomes costs were obtained from previously conducted ICU cost studies and Medicare payment fee schedules. All costs were estimated in 2018 US Dollars.

Results

The per patient costs associated with dexmedetomidine, propofol, and midazolam were estimated to be $21,115, $27,073, and $27,603, respectively. Dexmedetomidine was associated with a savings of $5958 per patient compared to propofol and a saving of $6487 compared to midazolam. These savings were primarily driven by a reduction in ICU length of stay and the degree of monitoring and management.

Conclusion

Dexmedetomidine was associated with reduced costs when compared to propofol or midazolam used for short-term sedation during MV in the ICU, suggesting sedative choice can have a potential impact on overall cost per episode.

Center Effects in Hospital Mortality of Critically Ill Patients With Hematologic Malignancies

OBJECTIVES

We aimed to investigate center effects on hospital mortality of ICU patients with hematologic malignancies and to explore interactions between center and patients characteristics.

DESIGN

Multicenter prospective cohort.

SETTING

Seventeen ICUs across France and Belgium.

PATIENTS

One-thousand eleven patients with hematologic malignancies hospitalized in ICUs.

INTERVENTIONS

Reanalysis of the original data using state-of-the-art statistical methods with permutation procedures for testing multiple random effects.

MEASUREMENTS AND MAIN RESULTS

Average crude mortality was 39% and varied from 11% to 58% across centers. There was a significant center effect on the mean hospital mortality, after adjustment on individual prognostic factors (p < 0.001; median adjusted odds ratio for center effect 1.57 [interquartile range, 1.24-2.18]). There was also a quantitative interaction between center and the effect of the Sequential Organ Failure Assessment score: higher scores were associated with higher mortality (odds ratio for 1 point = 1.24 on average; 95% CI, 1.15-1.33) but with a magnitude that depended on center (p = 0.028).

CONCLUSIONS

Between-center heterogeneity in hospital mortality was confirmed after adjustment for individual prognostic factors. It was partially explained by center experience in treating oncology patients. Interestingly, center effect was similar in magnitude to that of known mortality risk factors.

Pain management in trauma patients affected by the opioid epidemic: A narrative review

Acute and chronic pain in trauma patients remains a challenging entity, particularly in the setting of the escalating opioid epidemic. It has been reported that chronic opioid use increases the likelihood of hospital admissions as a result of traumatic injuries. Furthermore, patients admitted with traumatic injuries have a greater than average risk of developing opioid use disorder after discharge. Practitioners providing care to these patients will encounter the issue of balancing analgesic goals and acute opioid withdrawal with the challenge of reducing postdischarge persistent opioid use. Additionally, the practitioner is faced with the worrisome prospect that inadequate treatment of acute pain may lead to the development of chronic pain and overtreatment may result in opioid dependence. It is therefore imperative to understand and execute alternative nonopioid strategies to maximize the benefits and reduce the risks of analgesic regimens in this patient population. This narrative review will analyze the current literature on pain management in trauma patients and highlight the application of the multimodal approach in potentially reducing the risks of both short- and long-term opioid use. LEVEL OF EVIDENCE: Narrative review, moderate to High.

Dexmedetomidine protects against sepsis‑associated encephalopathy through Hsp90/AKT signaling

Sepsis‑associated encephalopathy (SAE) is characterized by neuronal apoptosis and changes in mental status. Accumulating evidence has. indicated that dexmedetomidine is capable of protecting the brain against external stimuli and improving cognitive dysfunctions. The aim of the present study was to investigate the possible neuroprotective effects of dexmedetomidine on SAE and the role of heat‑shock protein (Hsp)90/AKT signaling in an experimental model of sepsis. The SAE model was established by cecal ligation and perforation (CLP) in vivo and lipopolysaccharide (LPS) treated hippocampal neuronal cultures in vitro. It was found that dexmedetomidine inhibited caspase‑3, but increased the expression level ofBcl‑2 in CLP rats. CLP rats also exhibited a decreased level of phosphorylated AKT Thr 308 and Hsp90, and their expression could be reversed by treatment with dexmedetomidine. Additionally, application of dexmedetomidine increased cell survival and decreased neuronal apoptosis in vitro. Furthermore, the neuroprotective effects of dexmedetomidine could be reversed by 17‑AAG (a Hsp90 inhibitor), or wortmannin (a PI3K inhibitor). Analysis of TUNEL staining indicated that dexmedetomidine improved LPS‑induced neuronal apoptosis, which could be eradicated by AKT short hairpin RNA transfection, prazosin or yohimbine. Finally, dexmedetomidine ameliorated both the emotional and spatial cognitive disorders without alteration in locomotor activity. The present findings suggested that dexmedetomidine may protect the brain against SAE, and that the Hsp90/AKT pathway may be involved in this process.

Delirium in the Intensive Care Unit: Is Dexmedetomidine Effective?

Delirium in the intensive care unit affects approximately 30% of patients despite vigorous efforts to encourage the use of effective screening tools and preventive strategies. The success of pharmacological treatment of delirium remains equivocal; moreover, a paucity of research supports the use of atypical antipsychotic medications. However, dexmedetomidine appears to have a promising role in delirium management. This review includes an overview of the pathophysiology and types of delirium and describes 2 established tools used to screen for delirium. Published research related to the use of dexmedetomidine in the management of delirium is also discussed. The authors make recommendations for critical care nurses on dexmedetomidine use in the context of providing evidence-based nursing care to intensive care unit patients with delirium.

Dexmedetomidine reduces inflammation in traumatic brain injury by regulating the inflammatory responses of macrophages and splenocytes

Traumatic brain injury (TBI) affects people in all demographics, since it is associated with a variety of chronic degenerative diseases, such as Alzheimer's and Parkinson's disease. In TBI, the central nervous system elicits an immune response involving various immune cells that is necessary for healing and defending the body against pathogens, but can also cause secondary damage to the brain if the response is prolonged. In our clinical practice, it has been identified that administration of dexmedetomidine was associated with reduced production of inflammatory cytokines in patients with TBI, which led to the hypothesis that dexmedetomidine may regulate certain inflammatory responses. To test this hypothesis, the roles of dexmedetomidine in the immune system of mice were investigated. Different biological assays were used to assess the influence of dexmedetomidine on the production of inflammatory cytokines, including tumor necrosis factor (TNF)-α, interleukin (IL)-6, IL-8 and IL-1β. To understand how dexmedetomidine affects different types of immune cells, the influence of dexmedetomidine on splenocytes was also investigated. Finally, the effects of dexmedetomidine on macrophage activation and inflammatory functions were studied. In the present study, clinical observations and in vivo results using a mouse model of TBI revealed the regulatory functions of dexmedetomidine in TBI-associated immune response.

Beyond Opioids for Pain Management in Adult Critically Ill Patients

Critically ill patients commonly experience pain, and the provision of analgesia is an essential component of intensive care unit (ICU) care. Opioids are the mainstay of pain management in the ICU but are limited by their adverse effects, risk of addiction and abuse, and recent drug shortages of injectable formulations. A multimodal analgesia approach, utilizing nonopioid analgesics as adjuncts to opioid therapy, is recommended since they may modulate the pain response and reduce opioid requirements by acting on multiple pain mediators. Nonopioid analgesics discussed in detail in this article are acetaminophen, α-2 receptor agonists, gabapentinoids, ketamine, lidocaine, and nonsteroidal anti-inflammatory drugs. This literature review describes the clinical pharmacology, supportive ICU and relevant non-ICU data, and practical considerations associated with the administration of nonopioid analgesics in critically ill adult patients.

Sedative drugs used for mechanically ventilated patients in intensive care units: a systematic review and network meta-analysis

BACKGROUND

The effects of different sedative drugs on all-cause mortality rate, duration of ICU stay, and risk of delirium in mechanically ventilated ICU patients are unclear. This meta-analysis aimed to compare the effectiveness and safety of individual sedative drugs and drug combinations in mechanically ventilated ICU patients.

MATERIALS AND METHODS

Medline, Embase, Cochrane, EBSCOhost, and ISI Web of Science databases were searched for studies that assessed sedation in ICU mechanically ventilated patients. A Bayesian random-effects model was used to combine the direct comparisons and indirect evidence.

RESULTS

Thirty-one randomized, controlled trials were included, which consisted of 4491 patients who received one of seven sedative drugs or a combination of drugs. There were no significant differences regarding the all-cause mortality rate. Compared to propofol, inhalation anesthetics (hazard ratio [HR] 0.121; 95% credible interval [CrI] -7.58 to 7.62), alpha agonists (HR 2.2; 95% CrI 0.776 to 5.22), propofol with benzodiazepines (HR 0.306; 95% CrI -6.97 to 7.65), ketamine with benzodiazepines (HR 6.57; 95% CrI -6.05 to 19.1) and placebo (HR 2.4; 95% CrI -5.37 to 10.3), benzodiazepines (HR 3.62; 95% CrI 0.834 to 6.2) may increase the duration of ICU stay. Compared to alpha agonists, propofol (HR 2.4; 95% CrI 0.304 to 21.1) and placebo (HR 6.12; 95% CrI 0.745 to 54.6), benzodiazepines (HR 2.59; 95% CrI 1.08 to 7.4) were associated with incremental risks of delirium.

CONCLUSION

Compared to propofol, benzodiazepines may increase the duration of ICU stay. Compared to alpha agonists, benzodiazepines were associated with an increased risk of delirium.

A Comparative Study of Midazolam Alone or in Combination with Dexmedetomidine or Clonidine for Awake Fiberoptic Intubation

Background:

Awake fiberoptic intubation (AFOI) is the gold standard technique for managing patients with anticipated difficult airway. Conscious sedation is desirable, not only to make the procedure more tolerable and comfortable for the patient but also to ensure optimal intubating conditions. Ideal sedation regime for AFOI should provide comfort, cooperation, hemodynamic stability, and amnesia along with maintenance of spontaneous respiration. Several sedative agents have been assessed over the past two decades for this purpose but α2 agonists appear to be the favorable choice owing to its sedative, analgesic, amnestic, and sympatholytic properties along with good hemodynamic profile.

Aims:

The present study has been aimed to recognize the characteristics of dexmedetomidine, clonidine, and midazolam and to compare their efficacy in providing optimal intubating conditions as well as hemodynamic stability during AFOI.

Settings and Design:

A prospective double-blind randomized study done in tertiary care hospital.

Materials and Methods:

Sixty patients of American Society of Anesthesiologists physical status Classes I and II aged 18–60 years with anticipated difficult airway were randomly allocated into three groups. All the patients received injection midazolam bolus followed by sedation infusion of midazolam, dexmedetomidine, and clonidine according to the allocated group. Primary outcome includes the time to achieve Ramsay Sedation Score (RSS) ≥2, time taken in intubation, intubation score, comfort score for fiberoptic insertion and intubation, and patient tolerance after intubation. The secondary outcome was hemodynamic, and respiratory variables include changes in heart rate (HR), mean arterial pressure (MAP), oxygen saturation (SpO₂), and respiratory rate during the procedure.

Statistical Analysis:

All data were recorded, summarized, tabulated, and statistically analyzed using SPSS 16.0 version (Chicago, Inc., USA). The data were presented in mean ± standard deviation. P < 0.05 was considered as statistically significant.

Results:

All the three groups were comparable in terms of demographic profile. Time to achieve RSS ≥2 and mean intubation time was significantly less in Groups D and C as compared to Group M (P < 0.001). Among groups, Group D took least time to achieve RSS ≥2 (5.53 ± 0.74) and mean intubation time (4.53 ± 0.91). Similarly, overall intubation score, comfort, and patient tolerance score were significantly more in Group M as compared to Groups D and C (P < 0.001). Among the groups, Group D achieved least intubation score (3.80 ± 0.67) and comfort score (2.53 ± 0.74). Although Groups D and C have a lower mean HR and MAP during the procedure and intubation compared to Group M, the incidence of SpO₂ is most frequent with clonidine.

Conclusions:

Patients who received α2 agonist were calmer and cooperative with less pain and discomfort than the patients who received midazolam. Dexmedetomidine allows better endurance, stable hemodynamics, and patent airway as compared to clonidine.

Effects of different doses of dexmedetomidine on analgesic efficacy and inflammatory cytokines in patients undergoing laparoscopic surgery

The effects of different doses of dexmedetomidine on analgesic efficacy and inflammatory cytokines in patients with laparoscopic surgery were investigated. A total of 179 laparoscopic patients from March 2015 to May 2017 were enrolled and randomly divided into the control group (group A) and three experimental groups with different doses of dexmedetomidine (group B: 0.25; group C: 0.5 and group D: 1 µg/kg). Results showed that there was no significant difference between the four groups in the operation time, the amount of surgical bleeding and intraoperative fluid infusion. The VAS score of group A was significantly higher than the other three groups. In addition, the VAS score of group D at each time-point was the lowest. There was no significant difference regarding the agitation score and sedation score between group A and group B. Furthermore, the restlessness score and sedation score in group C were significantly lower than those in group A and group B. Next we found that CRP and TNF-α in group A and group B were significantly higher than those in groups C and D. In addition, IL-10 in group D was significantly higher than that in group C. Moreover, patients in group C had the least adverse reaction effects. In conclusion, medium dosage of dexmedetomidine cannot only effectively relieve the pain of laparoscopic patients but also regulate the secretion of inflammatory cytokines.

Pediatric Cardiac Surgery and Pain Management: After 40 Years in the Desert, Have We Reached the Promised Land?

Pain prevention in the pediatric population is mandatory and an integrative aspect of medical practice. Optimal pain management is the right of all patients and the responsibility of all health professionals. The key to adequate pain management is assessing its presence and severity, identifying those who require intervention, and appreciating treatment efficacy. The population of pediatric patients undergoing cardiac surgery is unique in both clinical severity and hemodynamic response to painful stimuli, thus making pain management even more challenging. In this review, we will describe the different pain assessment tools as well as intra- and postoperative regimens of pain management.

Dexmedetomidine versus ketofol sedation for outpatient diagnostic transesophageal echocardiography: A randomized controlled study

Background

Moderate sedation is required for out-patient transesophageal echocardiography (TEE). Our objective was to compare the effect of Ketofol and dexmedetomidine for outpatient procedural sedation in diagnostic TEE with a hypothesis that Ketofol would be as effective as dexmedetomidine. Patients and.

Methods

Fifty adult patients of age group 18-60 years with atrial septal defect, rheumatic valvular heart disease undergoing diagnostic TEE in the outpatient echocardiography laboratory were randomized into two groups, group D and group KF. GROUP D: Dexmedetomidine infusion -200 μg in 20 ml normal saline. GROUP KF: Ketofol infusion: (ketamine: propofol, 1mg: 3 mg in 20 ml syringe). Loading dose of drug at 1ml/kg/hour IV till Ramsay sedation score (RSS) ≥ 3 achieved followed by maintenance infusion at 0.05 ml/kg/hour till end of procedure.

Results

The primary outcome - time to achieve Ramsay sedation score ≥ 3 was significantly lesser with Ketofol as compared to Dexmedetomidine 260[69] seconds vs 460 [137], (p value<0.05).

Conclusion

In out-patient setting, ketofol is favourable over dexmedetomidine for sedation regimen for diagnostic TEE as lesser time is taken to achieve optimal sedation with lesser hemodynamic perturbations, post procedure complications and better cardiologist satisfaction.

Alpha-2 adrenergic agonists for the prevention of cardiac complications among adults undergoing surgery

BACKGROUND

The surgical stress response plays an important role on the pathogenesis of perioperative cardiac complications. Alpha-2 adrenergic agonists attenuate this response and may help prevent postoperative cardiac complications.

OBJECTIVES

To determine the efficacy and safety of α-2 adrenergic agonists for reducing mortality and cardiac complications in adults undergoing cardiac surgery and non-cardiac surgery.

SEARCH METHODS

We searched CENTRAL (2017, Issue 4), MEDLINE (1950 to April Week 4, 2017), Embase (1980 to May 2017), the Science Citation Index, clinical trial registries, and reference lists of included articles.

SELECTION CRITERIA

We included randomized controlled trials that compared α-2 adrenergic agonists (i.e. clonidine, dexmedetomidine or mivazerol) against placebo or non-α-2 adrenergic agonists. Included trials had to evaluate the efficacy and safety of α-2 adrenergic agonists for preventing perioperative mortality or cardiac complications (or both), or measure one or more relevant outcomes (i.e. death, myocardial infarction, heart failure, acute stroke, supraventricular tachyarrhythmia and myocardial ischaemia).

DATA COLLECTION AND ANALYSIS

Two authors independently assessed trial quality, extracted data and independently performed computer entry of abstracted data. We contacted study authors for additional information. Adverse event data were gathered from the trials. We evaluated included studies using the Cochrane 'Risk of bias' tool, and the quality of the evidence underlying pooled treatment effects using GRADE methodology. Given the clinical heterogeneity between cardiac and non-cardiac surgery, we analysed these subgroups separately. We expressed treatment effects as pooled risk ratios (RR) with 95% confidence intervals (CI).

MAIN RESULTS

We included 47 trials with 17,039 participants. Of these studies, 24 trials only included participants undergoing cardiac surgery, 23 only included participants undergoing non-cardiac surgery and eight only included participants undergoing vascular surgery. The α-2 adrenergic agonist studied was clonidine in 21 trials, dexmedetomidine in 24 trials and mivazerol in two trials.In non-cardiac surgery, there was high quality evidence that α-2 adrenergic agonists led to a similar risk of all-cause mortality compared with control groups (1.3% with α-2 adrenergic agonists versus 1.7% with control; RR 0.80, 95% CI 0.61 to 1.04; participants = 14,081; studies = 16). Additionally, the risk of cardiac mortality was similar between treatment groups (0.8% with α-2 adrenergic agonists versus 1.0% with control; RR 0.86, 95% CI 0.60 to 1.23; participants = 12,525; studies = 5, high quality evidence). The risk of myocardial infarction was probably similar between treatment groups (RR 0.94, 95% CI 0.69 to 1.27; participants = 13,907; studies = 12, moderate quality evidence). There was no associated effect on the risk of stroke (RR 0.93, 95% CI 0.55 to 1.56; participants = 11,542; studies = 7; high quality evidence). Conversely, α-2 adrenergic agonists probably increase the risks of clinically significant bradycardia (RR 1.59, 95% CI 1.18 to 2.13; participants = 14,035; studies = 16) and hypotension (RR 1.24, 95% CI 1.03 to 1.48; participants = 13,738; studies = 15), based on moderate quality evidence.There was insufficient evidence to determine the effect of α-2 adrenergic agonists on all-cause mortality in cardiac surgery (RR 0.52, 95% CI 0.26 to 1.04; participants = 1947; studies = 16) and myocardial infarction (RR 1.01, 95% CI 0.43 to 2.40; participants = 782; studies = 8), based on moderate quality evidence. There was one cardiac death in the clonidine arm of a study of 22 participants. Based on very limited data, α-2 adrenergic agonists may have reduced the risk of stroke (RR 0.37, 95% CI 0.15 to 0.93; participants = 1175; studies = 7; outcome events = 18; low quality evidence). Conversely, α-2 adrenergic agonists increased the risk of bradycardia from 6.4% to 12.0% (RR 1.88, 95% CI 1.35 to 2.62; participants = 1477; studies = 10; moderate quality evidence), but their effect on hypotension was uncertain (RR 1.19, 95% CI 0.87 to 1.64; participants = 1413; studies = 9; low quality evidence).These results were qualitatively unchanged in subgroup analyses and sensitivity analyses.

AUTHORS' CONCLUSIONS

Our review concludes that prophylactic α-2 adrenergic agonists generally do not prevent perioperative death or major cardiac complications. For non-cardiac surgery, there is moderate-to-high quality evidence that these agents do not prevent death, myocardial infarction or stroke. Conversely, there is moderate quality evidence that these agents have important adverse effects, namely increased risks of hypotension and bradycardia. For cardiac surgery, there is moderate quality evidence that α-2 adrenergic agonists have no effect on the risk of mortality or myocardial infarction, and that they increase the risk of bradycardia. The quality of evidence was inadequate to draw conclusions regarding the effects of alpha-2 agonists on stroke or hypotension during cardiac surgery.

Application of pre-injection of dexmedetomidine of different doses in pediatric intravenous general anesthesia without tracheal intubation

This study observed the clinical efficacy of pre-injection of dexmedetomidine of different doses before surgery and the adverse reactions during the recovery period in pediatric intravenous general anesthesia without tracheal intubation. Pediatric patients who received general anesthesia without tracheal intubation before surgery from January 2016 to March 2017 were randomly divided into four groups (n=30), and were respectively treated with intravenous pump infusion of loaded dexmedetomidine of high-dose (2.5 µg/kg), middle-dose (1.5 µg/kg) and low-dose (0.5 µg/kg), while the children in the control group received injection of normal saline in same dose. Then, the mean arterial pressure (MAP) at different time points (5 and 10 min after administration, after anesthesia and after surgery), heart rate, Ramsay sedation score changes and adverse reactions during recovery period of anesthesia of pediatric patients were compared among four groups. At 5 and 10 min after administration, Ramsay scores of high-dose group and middle-dose group were higher than that of the control group, and the differences had statistical significance (P<0.05). There was no significant difference in comparison of Ramsay scores between low-dose group and the control group. The MAP and heart rate after anesthesia and after surgery of pediatric patients with pump infusion of dexmedetomidine in the three groups were decreased significantly compared to those of the control group, and the differences had statistical significance (P<0.05). The incidence rate of adverse reaction of pediatric patients during the recovery period after pump infusion in the three groups and the control group was, respectively, 13/30, 8/30, 7/30 and 8/30, and the differences were statistically significant (P<0.05). The sedative effect and safety of pre-injection of dexmedetomidine in pediatric intravenous general anesthesia without tracheal intubation are promising, and the medium dosage can maximize the anesthetic effect with less side effects.

Reduced mitochondrial response sensitivity is involved in the anti‑apoptotic effect of dexmedetomidine pretreatment in cardiomyocytes

Dexmedetomidine is a commonly used α2-adreno-ceptor agonist, which affects various organs, including providing beneficial effects on the heart. However, the mechanism underlying the cardiac benefit remains to be fully elucidated. In the present study, it was demonstrated that dexmedetomidine pretreatment on primary cultured rat cardiomyocytes protected against reactive oxygen species (ROS)‑induced apoptosis. In terms of the potential mechanism, it was demonstrated that dexmedetomidine inhibited mitochondrial biogenesis and mitochondrial respiratory complexes, but with increased coupling efficiency. However, dexmedetomidine upregulated mitochondrial membrane potential (Δψm) and resisted against the loss of Δψm induced by carbonilcyanide p‑triflouromethoxyphenylhydrazone. Due to the importance of mitochondria affecting ROS, the present study investigated the dexmedetomidine‑suppressed mitochondrial response to H2O2 stimulation, which was explained by suppressed ROS levels and the suppression of the increased oxygen consumption rate. Results demonstrated for the first time, to the best of our knowledge, a novel protective mechanism for dexmedetomidine on cardiomyocytes through the attenuated response of mitochondria towards H2O2, which had a protective effect against ROS‑induced apoptosis.

A Comparative Study Evaluating Effects of Intravenous Sedation by Dexmedetomidine and Propofol on Patient Hemodynamics and Postoperative Outcomes in Cardiac Surgery

Background

The use of intravenous sedation during cardiac surgery to reduce awareness has been practised routinely during past few years and the two most commonly used drugs include propofol and dexmedetomidine, but their effects on hemodynamics and postoperative outcomes in cardiac surgery is continually being evaluated.

Aims

The aim of this study was to compare the effects of anesthesia by dexmedetomidine and propofol on the hemodynamic variables and postoperative outcomes in patients who were planned for elective cardiac surgery.

Settings

Cardiac operating room of a tertiary care hospital.

Design

A prospective, randomized controlled, double-blind clinical trial.

Materials and Methods

Sixty patients were randomized to receive either a continuous infusion of propofol (0.25-1 mg/kg/h) or dexmedetomidine bolus of 1 μg/kg over 10 min followed by infusion (0.2-0.6 μg/kg/h) after induction of anesthesia. The anesthesia technique and physiological monitoring including bispectral index monitoring were similar among both the groups. Hemodynamic variables (mean heart rate [HR], mean arterial pressure [MAP]) were noted at predefined time intervals, intraoperative vasopressor or inotrope requirements and postoperative outcomes including postoperative ventilation time and length of stay in the Intensive Care Unit (ICU) were also recorded.

Statistical Analysis

Statistics was done using SPSS V 20 (IBM, NY) using Student's t-test, analysis of variance, and Mann-Whitney U-test, and a P < 0.05 was considered to indicate a significant difference.

Results and Conclusions

HR and MAP were significantly less in dexmedetomidine group compared to propofol group (P < 0.05). Both the groups had a similar requirement of vasopressors and inotropes. The duration of postoperative ventilation and length of stay in the ICU were significantly shorter in the dexmedetomidine group (P < 0.05). The risk of delirium was significantly less in dexmedetomidine group (P < 0.05). From our study we concluded, that the perioperative infusion of dexmedetomidine produces better hemodynamic stability, reduces the risk of postoperative delirium, and leads to shorter ICU stay.

Safety and efficacy of ketamine-dexmedetomidine versus ketamine-propofol combinations for sedation in patients after coronary artery bypass graft surgery

Background and Aims:

Prolonged mechanical ventilation after cardiac surgery is associated with serious complications that increase morbidity and mortality. The present study was designed to compare ketamine-propofol (KP) and ketamine-dexmedetomidine (KD) combinations for sedation and analgesia in patients after coronary artery bypass graft (CABG) surgery as regards hemodynamics, total fentanyl dose, time of weaning from mechanical ventilation, time of extubation, and any adverse outcome.

Materials and Methods:

Seventy post-CABG patients were sedated using ketamine 1 mg/kg IV then 0.25 mg/kg/h infusion combined with either dexmedetomidine or propofol to maintain Ramsay sedation score ≥4 during assisted ventilation. Group KP received ketamine + propofol 1 mg/kg bolus followed by 25–50 μg/kg/min. Group KD received ketamine + dexmedetomidine 1.0 μg/kg over 20 min and then 0.2–0.7 μg/kg/h. Total dose of fentanyl in the first 24 h, time of weaning, time of extubation, mean arterial blood pressure, heart rate, and Intensive Care Unit (ICU) stay time were recorded.

Statistics:

Sample size of 35 patients was calculated for 90% power, α = 0.05, β = 0.1, and anticipated effect size = 0.40 using sample size software (G*Power version 3.00.10, Germany). Analytic statistics was performed on IBM compatible computer using SPSS version 11.5 (IBM, New York, United States) software package under Windows XP operating system. All results presented in the form of mean ± standard deviation. Data compared using unpaired Student's t-test, P < 0.05 was considered as statistically significant.

Results:

Group KD showed a significant decrease in mean time of weaning and extubation in group KD in comparison with group KP (374.05 ± 20.25 min vs. 445.23 ± 21.7 min, respectively, P < 0.001) (432.4 ± 19.4 min and 504 ± 28.7 min, respectively, P < 0.0001). Fentanyl consumption showed a significant decrease in group KD in comparison with group KP (41.94 ± 20.43 μg and 152.8 ± 51.2 μg, respectively, with P < 0.0001). There were insignificant difference between both groups as regards hemodynamic stability and length of ICU stay.

Conclusion:

Using KD combination for sedation, post-CABG surgery provided short duration of mechanical ventilation with less fentanyl dose requirement in comparison with KP with insignificant difference in both groups as regards hemodynamic stability and length of the ICU stay.

Pediatric Perioperative Pain Management

Effective perioperative pain control in pediatric patients undergoing orthopedic surgery remains a challenge. Developing a successful pain control regimen begins preoperatively with assessment of the patient and discussion with the patient and family regarding expectations. Perioperative pain control regimens are customized based on the type of surgery, patient characteristics, and anticipated severity and duration of the postoperative pain. Recent study focuses on multimodal strategies and regional anesthesia options, allowing for decreased opioid use. This article provides an evidence-based overview of preoperative, intraoperative, and postoperative pain control for the pediatric orthopedic patient.

A Comparative Study between Intrathecal Isobaric Ropivacaine 0.75% Plus Dexmedetomidine and Isobaric Ropivacaine 0.75% Plus Fentanyl for Lower Limb Surgeries

Background:

Spinal anesthesia is used commonly intraoperatively. However, local anesthetics are associated with relatively short duration of action. A number of adjuvants have been used to prolong the postoperative analgesia.

Objectives:

To compare efficacy of dexmedetomidine and fentanyl when given intrathecally as an adjuvant to 2.5 ml of 0.75% isobaric ropivacaine.

Materials and Methods:

Sixty selected patients were randomized to receive 2.5 ml of 0.75% isobaric ropivacaine with dexmedetomidine 5 mcg (Group RD) or 20 mcg of fentanyl (Group RF) intrathecally for lower limb surgeries, block characteristics, hemodynamic changes, and adverse effects were compared.

Results:

Efficacy of both the drugs when given intrathecally was studied. Mean time needed for sensory blockade at T10 was 156.4667 ± 33.78 s in Group RD and 185.2000 ± 35.17 s in Group RF. The results are clinically and statistically significant (P - 0.002). The mean of total duration of sensory block in Group RD was 194.400 min while it was 139.9000 min in Group RF which was clinically and statistically significant (P - 0.0001). Time taken for onset of motor block was almost same in both groups. The mean of total duration of motor block in Group RD was 136.7333 min while it was 94.8667 min in Group RF which was clinically and statistically significant (P - 0.000).

Conclusion:

Dexmedetomidine at a dose of 5 μg added to 2.5 ml of ropivacaine provided earlier sensory blockade, prolonged duration of sensory and motor blockade for patients under intrathecal anesthesia for lower limb surgeries with no sedation.

Dexmedetomidine ameliorates the inflammatory immune response in rats with acute kidney damage

It has been demonstrated that dexmedetomidine (Dex) can protect patients with acute kidney injury from experiencing further tissue damage, however its mechanism of action remains unclear. The present study investigated the immune modulatory functions of Dex in rats with acute kidney injury (AKI) induced via injection of lipopolysaccharide into the tail vein. ELISA analysis showed that Dex reduced the levels of inflammatory cytokines in rats with AKI in a dose dependent manner. Furthermore, the regulatory effects of Dex on cytokine production disappeared when the α-2 adrenergic receptor antagonist Yohimbine (YOH) was added. For a detailed investigation on how Dex regulates the immune response in rats with AKI, the impact of Dex on the viability of splenocytes and lymphocytes was determined and it was determined that Dex did not influence splenocyte and lymphocyte viability. In addition, ELISA tests showed that Dex regulated the production of the T-helper (Th) 17 cytokines interleukin (IL)-17 and IL-23, but not the Th1 cytokine tumor necrosis factor α, in splenocytes and lymphocytes. To confirm whether Dex functioned as an α-2-adrenergic receptor in these immune regulations, YOH was administered together with Dex. When Dex and YOH were administered together, the regulatory functions of Dex were reduced, confirming that Dex acted as an agonist on the α-2-adrenergic receptor. Thus the results of the current study may provide novel insights regarding how Dex modulates immune functions in AKI.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSION

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