Dexmedetomidine in anaesthesia

Impact of Dexmedetomidine on Hemodynamics, Plasma Catecholamine Levels, and Delirium Incidence Among Intubated Patients in the ICU--A Randomized Controlled Trial

Objective

To investigate the impact of various sedative medications on hemodynamics and plasma levels of epinephrine (E) and norepinephrine (NE) in mechanically ventilated patients postoperatively in the intensive care unit (ICU).

Methods

Ninety-seven patients admitted to the ICU undergoing postoperative mechanical ventilation with tracheal intubation and continuous analgesic sedation following general anesthesia were randomly assigned to either the observation group (dexmedetomidine) (n = 49) or the control group (propofol) (n = 48) in this randomized controlled trial. Upon transfer to the ICU, vital signs (heart rate [HR], respiratory rate [RR], mean arterial pressure [MAP]) were recorded prior to the initiation of the sedation treatment (T0), at one-hour post sedation (T1) and two hours following tracheal extubation (T2), plasma levels of epinephrine (E) and norepinephrine (NE) were measured at these time points. The incidence of delirium was recorded in both groups.

Results

MAP between the two groups at both T0 and T1 At T2 plasma NE and HR were found to be lower in the observation group compared to the control group (P < 0.001). Among the patients receiving antihypertensive medication in the ICU, NE levels were significantly lower in the observation group compared to the control group (P = 0.019) Among the patients not receiving antihypertensive medication, both NE (P < 0.001) and MAP (P = 0.001) levels were lower in the observation group compared to the control group. The incidence of delirium in the observation group (dexmedetomidine) was not significantly different from that in the control group (propofol).

Conclusion

With dexmedetomidine sedation, blood pressure fluctuated less, plasma catecholamine levels were lower, and sympathetic inhibition was stronger in patients before and after extubation. However, it did not significantly reduce the incidence of postoperative delirium.

Methylphenidate Reversal of Dexmedetomidine-Induced Versus Ketamine-Induced Sedation in Rats

BACKGROUND

Dexmedetomidine and ketamine have long elimination half-lives in humans and have no clinically approved reversal agents. Methylphenidate enhances dopaminergic and noradrenergic neurotransmission by inhibiting reuptake transporters for these arousal-promoting neurotransmitters. Previous studies in rats demonstrated that intravenous methylphenidate induces emergence from isoflurane and propofol general anesthesia. These 2 anesthetics are thought to act primarily through enhancement of inhibitory Gamma-aminobutyric acid type A (GABAA) receptors. In this study, we tested the behavioral and neurophysiological effects of methylphenidate in rats after low and high doses of dexmedetomidine (an alpha-2 adrenergic receptor agonist) and ketamine (an N-methyl-D-aspartate [NMDA] receptor antagonist) that induce sedation and unconsciousness, respectively.

METHODS

All experiments used adult male and female Sprague-Dawley rats (n = 32 total) and all drugs were administered intravenously in a crossover, blinded experimental design. Locomotion after sedating doses of dexmedetomidine (10 µg/kg) or ketamine (10 mg/kg) with and without methylphenidate (5 mg/kg) was tested using the open field test (n = 16). Recovery of righting reflex after either high-dose dexmedetomidine (50 µg/kg) or high-dose ketamine (50 mg/kg) with and without methylphenidate (1-5 mg/kg) was assessed in a second cohort of rats (n = 8). Finally, in a third cohort of rats (n = 8), frontal electroencephalography (EEG) was recorded for spectral analysis under both low and high doses of dexmedetomidine and ketamine with and without methylphenidate.

RESULTS

Low-dose dexmedetomidine reduced locomotion by 94% in rats. Methylphenidate restored locomotion after low-dose dexmedetomidine (rank difference = 88.5, 95% confidence interval [CI], 70.8-106) and the effect was blocked by coadministration with a dopamine D1 receptor antagonist (rank difference = 86.2, 95% CI, 68.6-104). Low-dose ketamine transiently attenuated mobility by 58% and was not improved with methylphenidate. Methylphenidate did not affect the return of righting reflex latency in rats after high-dose dexmedetomidine nor ketamine. Frontal EEG analysis revealed that methylphenidate reversed spectral changes induced by low-dose dexmedetomidine (F [8,87] = 3.27, P = .003) but produced only transient changes after high-dose dexmedetomidine. Methylphenidate did not induce spectral changes in the EEG after low- or high-dose ketamine.

CONCLUSIONS

Methylphenidate reversed behavioral and neurophysiological correlates of sedation, but not unconsciousness, induced by dexmedetomidine. In contrast, methylphenidate did not affect sedation, unconsciousness, nor EEG signatures in rats after ketamine. These findings suggest that methylphenidate may be efficacious to reverse dexmedetomidine sedation in humans.

From bench to bedside: A review of the application and potential of microcirculatory assessment by hand-held videomicroscopy

In clinical practice, there is vast knowledge regarding the evaluation of macrocirculatory parameters, such as systemic blood pressure and cardiac output, for the hemodynamic monitoring of patients. However, assessment of the microcirculation has not yet been incorporated into the bedside armamentarium. Hand-held intravital video microscopy enables the direct, noninvasive, evaluation of the sublingual microcirculation at the bedside, offering insights into the status of the systemic microcirculation. It is easily performed and may be employed in several clinical settings, providing immediate results that may help guide patient management. Therefore, the incorporation of hand-held intravital video microscopy into clinical practice may lead to tremendous improvements in the quality of care of critical, unstable patients or offer new data in the evaluation of patients with chronic diseases, especially those with microcirculatory involvement, such as occurs in diabetes.

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

Objective

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

Methods

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

Results

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

Conclusion

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

Impact of dexmedetomidine on electrophysiological properties and arrhythmia inducibility in adult patients referred for reentrant supraventricular tachycardia ablation

BACKGROUND

Drugs used for sedation/analgesia may affect the basic cardiac electrophysiologic properties or even supraventricular tachycardia (SVT) inducibility. Dexmedetomidine (DEX) is a selective alpha-2 adrenergic agonist with sedative and analgesic properties. A comprehensive evaluation on use of DEX for reentrant SVT ablation in adults is lacking. The present study aims to systematically assess the impact of DEX on cardiac electrophysiology and SVT inducibility.

METHODS

Hemodynamic, electrocardiographic, and electrophysiological parameters and SVT inducibility were assessed before and after DEX infusion in patients scheduled for ablation of reentrant SVT.

RESULTS

The population of this prospective observational study included 55 patients (mean age of 58.7 ± 14 years, 29 males [52.7%]). A decrease in systolic and diastolic blood pressure and in heart rate was observed after DEX infusion (p = 0.001 for all). DEX increased corrected sinus node refractory time, atrial effective refractory period, AH interval, AV Wenckebach cycle length, and AV node effective refractory period without affecting the His-Purkinje conduction or ventricular myocardium refractoriness. No AV blocks or sinus arrests occurred during DEX infusion. Globally, there was no difference in SVT inducibility in basal condition or after DEX infusion (46/55 [83.6%] vs. 43/55 [78.1%] patients; p = 0.55), without a difference in isoprenaline use (p = 1.0). In 4 (7.3%) cases, the SVT was inducible only after DEX infusion. In 34.5% of cases, DEX infusion unmasked the presence of an obstructive sleeping respiratory pattern, represented mainly by snoring.

CONCLUSIONS

DEX depresses sinus node function and prolongs atrioventricular refractoriness without significantly affecting the rate of SVT inducibility in patients scheduled for reentrant SVT ablation.

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Graph approaches for analysis of brain connectivity during dexmedetomidine sedation

Sedation is commonly used to relieve fear and anxiety during procedures. Dexmedetomidine (DEX), approved by the US Food and Drug Administration in 1999 for short-term sedation, is a selective alpha2-adrenoreceptor agonist. The use of DEX is increasing due to minimal respiratory depression and easy and quick awakening from sedation. Its sedative mechanisms are suggested to be related to changes in the interaction between brain regions. In this study, we used graph theory to investigate whether the altered network connection is associated with sedation. Electroencephalogram (EEG) recordings of 32 channels were acquired during awake and DEX-induced sedation for 20 participants. We extracted EEG epochs from the awake and the DEX sedation state. Using the graph theory, we compared the changes in the network connection parameters with the awake state. We observed that the slopes in 1/f dynamics, which indicate overall brain network characteristics, were greater during DEX-induced sedation compared to the awake state, suggesting a transition towards a random network behavior. In addition, network connections from the perspective of information processing were significantly disturbed in the alpha frequency band, unlike other frequency bands augmenting network connections. The alpha frequency band plays a prominent role in the function and interaction of cognitive activities. These results collectively indicate that changes in the brain network critical to cognition during DEX administration may also be related to the mechanism of sedation.

A comprehensive overview of clinical research on dexmedetomidine in the past 2 decades: A bibliometric analysis

Introduction: Dexmedetomidine is a potent, highly selective α-2 adrenoceptor agonist with sedative, analgesic, anxiolytic, and opioid-sparing properties. A large number of dexmedetomidine-related publications have sprung out in the last 2 decades. However, no bibliometric analysis for clinical research on dexmedetomidine has been published to analyze hot spots, trends, and frontiers in this field. Methods: The clinical articles and reviews related to dexmedetomidine, published from 2002 to 2021 in the Web of Science Core Collection, were retrieved on 19 May 2022, using relevant search terms. VOSviewer and CiteSpace were used to conduct this bibliometric study. Results: The results showed that a total of 2,299 publications were retrieved from 656 academic journals with 48,549 co-cited references by 2,335 institutions from 65 countries/regions. The United States had the most publications among all the countries (n = 870, 37.8%) and the Harvard University contributed the most among all institutions (n = 57, 2.48%). The most productive academic journal on dexmedetomidine was Pediatric Anesthesia and the first co-cited journal was Anesthesiology. Mika Scheinin is the most productive author and Pratik P Pandharipande is the most co-cited author. Co-cited reference analysis and keyword analysis illustrated hot spots in the dexmedetomidine field including pharmacokinetics and pharmacodynamics, intensive care unit sedation and outcome, pain management and nerve block, and premedication and use in children. The effect of dexmedetomidine sedation on the outcomes of critically ill patients, the analgesic effect of dexmedetomidine, and its organ protective property are the frontiers in future research. Conclusion: This bibliometric analysis provided us with concise information about the development trend and provided an important reference for researchers to guide future research.

Dexmedetomidine administration during brain tumour resection for prevention of postoperative delirium: a randomised trial

BACKGROUND

Delirium is common, especially after neurosurgery. Dexmedetomidine might reduce delirium by improving postoperative analgesia and sleep quality. We tested the primary hypothesis that dexmedetomidine administration during intracerebral tumour resection reduces the incidence of postoperative delirium.

METHODS

This randomised, double-blind, placebo-controlled trial was conducted in two tertiary-care hospitals in Beijing. We randomised 260 qualifying patients to either dexmedetomidine (n=130) or placebo (n=130). Subjects assigned to dexmedetomidine were given a loading dose of 0.6 μg kg^-1 followed by continuous infusion at 0.4 μg kg^-1 h^-1 until dural closure; subjects in the placebo group were given comparable volumes of normal saline. The primary outcome was the incidence of delirium, which was assessed with the Confusion Assessment Method twice daily during the initial 5 postoperative days.

RESULTS

The average (standard deviation) age of participating patients was 45 (12) yr, duration of surgery was 4.2 (1.5) h, and patients assigned to dexmedetomidine were given an average of 126 (45) μg of dexmedetomidine. There was less delirium during the initial 5 postoperative days in patients assigned to dexmedetomidine (22%, 28 of 130 patients) than in those given placebo (46%, 60 of 130 patients) with a risk ratio of 0.51 (95% confidence interval: 0.36-0.74, P<0.001). Postoperative pain scores with movement, and recovery and sleep quality were improved by dexmedetomidine (P<0.001). The incidence of safety outcomes was similar in each group.

CONCLUSIONS

Prophylactic intraoperative dexmedetomidine infusion reduced by half the incidence of delirium during the initial 5 postoperative days in patients recovering from elective brain tumour resection.

CLINICAL TRIAL REGISTRATION

NCT04674241.

Anesthetic Considerations in the Electrophysiology Laboratory: A Comprehensive Review

Catheter ablation procedures for arrhythmias or implantation and/or extraction of cardiac pacemakers can present many clinical challenges. It is imperative that there is clear communication and understanding between the anesthesiologist and electrophysiologist during the perioperative period regarding the mode of ventilation, hemodynamic considerations, and various procedural complications. This article provides a comprehensive narrative review of the anesthetic techniques and considerations for catheter ablation procedures, ventilatory modes using techniques such as high-frequency jet ventilation, and strategies such as esophageal deviation and luminal temperature monitoring to decrease the risk of esophageal injury during catheter ablation. Various hemodynamic considerations, such as the intraprocedural triaging of cardiac tamponade and fluid administration during catheter ablation, also are discussed. Finally, this review briefly highlights the early research findings on pulse-field ablation, a new and evolving ablation modality.

Efficacy and safety evaluation of dexmedetomidine for postoperative patient controlled intravenous analgesia: A systematic review and meta-analysis

Objective: To investigate the efficacy and safety of dexmedetomidine (DEX) for postoperative patient controlled intravenous analgesia (PCIA). Measurements: Two investigators independently searched Pubmed, Embase, Scopus, Cochrane Library and CBM for randomized controlled trials of DEX for PCIA. Main results: Thirty-seven studies with a total of 5,409 patients were included in this meta-analysis. Compared with analgesics alone, DEX for PCIA reduced pain score at 24 h [mean difference (MD) = -0.70; 95% confidence interval (CI): -0.85, -0.54; p < 0.00001, I ² = 90%] and 48 h postoperatively (MD = -0.43; 95% CI: -0.52, -0.34; p < 0.00001, I ² = 96%). Moreover, DEX reduced analgesics consumption during the first 24 h [standardized mean difference (SMD) = -0.25; 95% CI: -0.34, -0.16; p < 0.00001, I ² = 91%] and the number of resuscitation analgesics administered [odds ratio (OR) = 0.54; 95% CI: 0.44, 0.66; p < 0.00001, I ² = 72%]. Furthermore, DEX improved patient satisfaction (OR = 3.55; 95% CI: 2.36, 5.35; p < 0.00001, I ² = 60%), and reduced incidence of side effects, such as postoperative nausea and vomiting (PONV) (OR = 0.47; 95% CI: 0.39, 0.57; p < 0.00001, I ² = 59%) and pruritus after surgery (OR = 0.45; 95% CI: 0.30, 0.68; p = 0.0001, I ² = 0%). Besides, DEX attenuates inflammatory cytokine levels, such as IL-6 (MD = -5.73; 95% CI: -8.34, -3.12; p < 0.00001, I ² = 91%) and TNF-α (MD = -0.63; 95% CI: -0.76, -0.50; p < 0.00001, I ² = 89%). Finally, DEX increased the risk of bradycardia (OR = 1.66; 95% CI: 1.12, 2.45; p = 0.01, I ² = 15%), but the complication of hypotension did not differ between the two groups (OR = 1.30; 95% CI: 0.84, 2.04; p = 0.25, I ² = 0%). Conclusion: DEX is used for postoperative PCIA analgesia, which can significantly improve the analgesic effect, effectively control postoperative inflammatory response, reduce the dosage and adverse reactions of analgesics, and improve postoperative patient satisfaction. Of course, the impact of the immunosuppressive effect of DEX on the prognosis of patients needs further study. Systematic review registration: CRD42022340933, https://www.crd.york.ac.uk/prospero/.

Moderate sedation with dexmedetomidine-remifentanil is safer than deep sedation with propofol-remifentanil for endobronchial ultrasound while providing comparable quality: a randomized double-blind trial

OBJECTIVE

We compared dexmedetomidine-remifentanil vs. propofol-remifentanil in terms of safety and quality during sedation for Endobronchial ultrasonography (EBUS).

METHODS

A randomized, double-blind trial. Outpatients undergoing EBUS randomly received 1 μg/kg/hour dexmedetomidine or a target concentration of 2.5 μg/mL propofol, both combined with remifentanil initially targeted at 1.5 ng/mL and subsequently titrated. Additional sedatives were restricted. The primary outcome was the need for airway rescue interventions to treat oxygen desaturation.

RESULTS

Twenty-eight patients received dexmedetomidine-remifentanil and 27 received propofol-remifentanil. Airway rescue interventions were fewer in the dexmedetomidine group vs. the propofol one (23 vs. 76% patients, relative risk 3.21 (95% CI 1.55-6.64, P < 0.002)). Desaturation in the dexmedetomidine group was always resolved by increasing nasal oxygen flow, whereas additional interventions were needed in 60% of patients receiving propofol. Hypotension was more frequent in the propofol group, while hypertension, bradycardia and coughing were similar in both. Bronchoscopists' and patients' satisfaction were similar, although in the dexmedetomidine group two patients needed additional sedatives and two patients would not repeat the sedation technique.

CONCLUSION

Moderate sedation with dexmedetomidine-remifentanil for EBUS is safer than deep sedation with propofol-remifentanil but it would occasionally need additional sedatives to ensure patient satisfaction.

Risk factors for dexmedetomidine-associated bradycardia during spinal anesthesia: A retrospective study

Sedation with dexmedetomidine is needed for patients undergoing spinal anesthesia. However, dexmedetomidine sedation increases the incidence of bradycardia. We aimed to identify and to evaluate risk factors for bradycardia in patients undergoing spinal anesthesia with dexmedetomidine sedation. The records of 91 patients who underwent spinal anesthesia with sedation using dexmedetomidine were reviewed retrospectively. For this study, we identified 15 characteristics of included patients from this group who underwent lower leg surgery and had an estimated blood loss of <300 mL. We collected details on potential risk factors for bradycardia from their clinical records. These factors included age, American Society of Anesthesiologists classification, height, weight, sensory level of spinal anesthesia, history of hypertension, diabetes mellitus, loading, and maintenance dose of dexmedetomidine, tourniquet time, initial diastolic and systolic blood pressure, initial heart rate (HR), and anesthesia and surgery duration. The primary endpoint of this study was the occurrence of bradycardia. We identified potential risk factors using logistic regression analysis. The incidence of bradycardia was obtained in 23 (25%) of 91 patients. Initial HR and tourniquet time were significant individual predictive factors for the occurrence of bradycardia. Logistic regression analysis showed that adjusted baseline HR and duration of tourniquet use were risk factors for bradycardia. Patients should be monitored when undergoing spinal anesthesia with sedation using dexmedetomidine for bradycardia when they have a long tourniquet time. A low initial HR could also be a predictive factor for bradycardia.

Dexmedetomidine depresses neuronal activity in the subthalamic nucleus during deep brain stimulation electrode implantation surgery

Background

Micro-electrode recordings are often necessary during electrode implantation for deep brain stimulation of the subthalamic nucleus. Dexmedetomidine may be a useful sedative for these procedures, but there is limited information regarding its effect on neural activity in the subthalamic nucleus and on micro-electrode recording quality.

Methods

We recorded neural activity in five patients undergoing deep brain stimulation implantation to the subthalamic nucleus. Activity was recorded after subthalamic nucleus identification while patients received dexmedetomidine sedation (loading - 1 μg kg-1 over 10-15 min, maintenance - 0.7 μg kg-1 h-1). We compared the root-mean square (RMS) and beta band (13-30 Hz) oscillation power of multi-unit activity recorded by microelectrode before, during and after recovery from dexmedetomidine sedation. RMS was normalised to values recorded in the white matter.

Results

Multi-unit activity decreased during sedation in all five patients. Mean normalised RMS decreased from 2.8 (1.5) to 1.6 (1.1) during sedation (43% drop, p = 0.056). Beta band power dropped by 48.4%, but this was not significant (p = 0.15). Normalised RMS values failed to return to baseline levels during the time allocated for the study (30 min).

Conclusions

In this small sample, we demonstrate that dexmedetomidine decreases neuronal firing in the subthalamic nucleus as expressed in the RMS of the multi-unit activity. As multi-unit activity is a factor in determining the subthalamic nucleus borders during micro-electrode recordings, dexmedetomidine should be used with caution for sedation during these procedures.

Clinical trial number

NCT01721460.

Effects of opioid-free anesthesia on postoperative morphine consumption after bariatric surgery

STUDY OBJECTIVES

The objective of this study was to determine whether postoperative morphine requirement in obese patients undergoing laparoscopic bariatric surgery was reduced by opioid-free anesthesia (OFA), as compared to an anesthetic strategy using opioids (opioid balanced anesthesia (OBA)) and to investigate the differences that may exist between the use of clonidine and dexmedetomidine in the context of OFA.

DESIGN

Retrospective cohort study.

SETTING

Academic medical center in Lyon, France.

PATIENTS

257 patients who underwent laparoscopic bariatric surgery between March 2017 and March 2019. 77 patients were included in the OBA group and 180 in the OFA group. The OFA group was subdivided in two: 90 patients received OFA with clonidine (OFAC) and 90 received OFA with dexmedetomidine (OFAD).

MEASUREMENTS

Proportion of patients who did not receive morphine during the first 24 postoperative hours.

MAIN RESULTS

During the first 24 postoperative hours, the proportion of patients who did not require morphine was significantly higher in the OFA (87%) than in the OBA (52%) group (OR: 6.31; 95% CI [3.38; 11.80], P < 0.001). This difference remained significant after adjustment for age, body mass index, sex, type and duration of surgery (OR: 7.99; 95% CI [4.05; 16.48], P < 0.001). A greater proportion of patients in the OFAD (93%) than in the OFAC group (81%, P = 0.026) did not receive morphine during the same period.

CONCLUSIONS

OFA is associated with a lower morphine requirement than with OBA during the first 24 h after bariatric surgery. In addition, OFAD seems to be more effective than OFAC in order to reduce morphine consumption.

Effect of intratracheal dexmedetomidine combined with ropivacaine on postoperative sore throat: a prospective randomised double-blinded controlled trial

Background

The present study aimed to investigate whether intratracheal dexmedetomidine combined with ropivacaine reduces the severity and incidence of postoperative sore throat after tracheal intubation under general anaesthesia.

Methods

Two hundred patients with American Society of Anaesthesiologists physical status I-II who were subjected to general anaesthesia were randomly divided into four groups, namely, Group D, Group R, Group DR and Group S; these groups received intratracheal dexmedetomidine (1 µg/kg), 0.8% ropivacaine (40 mg), dexmedetomidine (1 µg/kg) combined with 0.8% ropivacaine (40 mg) and normal saline before endotracheal intubation, respectively. The primary outcomes were the incidence and grade of sore throat and hoarseness at 2 h and 24 h after surgery. Moreover, the modified Observer's Assessment of Alertness/Sedation Scale results were recorded at each time point. The secondary outcomes were intraoperative haemodynamic fluctuations, intraoperative anaesthetic drug requirements, and adverse reactions during and after surgery. The patients’ vital signs before induction, before superficial anaesthesia, after superficial anaesthesia, before intubation, after intubation, and 1 min after intubation were recorded. The use of anaesthetic drugs and occurrence of adverse effects were also recorded.

Results

The incidence and severity of sore throat were significantly lower in Group DR than in the other three groups 2 h after the operation, but they were only significantly lower in Group DR than in the control group 24 h after the operation. Moreover, compared with Group S and Group D, Group DR exhibited more stable haemodynamics during intubation. The doses of remifentanil and propofol were significantly lower in Group DR than in the other groups.

Conclusion

The combined use of dexmedetomidine and ropivacaine for surface anaesthesia before intubation significantly reduced the incidence and severity of postoperative sore throat. This treatment also decreased anaesthetic drug requirements and intraoperative haemodynamic fluctuations and caused no adverse effects.

Trial registration

This clinical research was registered at the Chinese Clinical Trial Registry (ChiCTR1900022907, Registration date 30/04/2019).

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.

The Effect of Dexmedetomidine on Postanesthesia Care Unit Discharge and Recovery: A Systematic Review and Meta-Analysis

BACKGROUND

Current evidence on the effect of dexmedetomidine in early postoperative recovery is limited. We conducted a systematic review to evaluate the effect of dexmedetomidine on the length of stay (LOS) and recovery profile in postanesthesia care unit (PACU) patients.

METHODS

The study protocol is registered on International Prospective Register of Systematic Reviews (PROSPERO; CRD42021240559). No specific funding or support was received. We conducted searches in MEDLINE, Embase, PubMed, and Cochrane Library to March 31, 2021 for peer-reviewed randomized controlled studies comparing adult patients who received intravenous dexmedetomidine and placebo undergoing noncardiac, nonneurosurgical procedures under general anesthesia. All studies reporting statistics relating to the duration of stay in the recovery ward or PACU, the primary outcome, were included. We performed individual random-effect meta-analysis on the primary and secondary outcomes (time to extubation, emergence agitation, cough, pain, postoperative nausea and vomiting, shivering, residual sedation, bradycardia, and hypotension) using Stata version 17.0. Evidence was synthesized as mean difference (MD) and risk ratio (RR) for continuous and dichotomous variables, respectively. The quality of evidence was assessed using the revised Cochrane risk-of-bias tool for randomized trials (RoB 2) tool and Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach.

RESULTS

Thirty-three studies including 2676 patients were eligible for analysis. All studies had low risk or some concerns of overall bias and provided low-to-high certainty evidence for all studied outcomes. Dexmedetomidine was not associated with a significantly increased PACU LOS (MD, 0.69 minute; 95% confidence interval [CI], -1.42 to 2.81 minutes). It was associated with a statistically but not clinically significant prolonged time to extubation (MD, 1 minute; 95% CI, 0.32-1.68 minutes). Dexmedetomidine was associated with significantly reduced incidence of emergence agitation (RR, 0.38; 95% CI, 0.29-0.52), cough (RR, 0.69; 95% CI, 0.61-0.79), pain (RR, 0.50; 95% CI, 0.32-0.80), postoperative nausea and vomiting (RR, 0.54; 95% CI, 0.33-0.86), and shivering (RR, 0.24; 95% CI, 0.12-0.49) in PACU. There was an increased incidence of hypotension (RR, 5.39; 95% CI, 1.12-5.89) but not residual sedation (RR, 1.23; 95% CI, 0.20-7.56) or bradycardia (RR, 5.13; 95% CI, 0.96-27.47) in the dexmedetomidine group.

CONCLUSIONS

The use of dexmedetomidine did not increase the duration of PACU LOS but was associated with reduced emergence agitation, cough, pain, postoperative nausea and vomiting, and shivering in PACU. There was an increased incidence of hypotension but not residual sedation or bradycardia in PACU.

Lack of influence of dexmedetomidine on rat glomus cell response to hypoxia, and on mouse acute hypoxic ventilatory response

Background and Aims

There is a lack of basic science data on the effect of dexmedetomidine on the hypoxic chemosensory reflex with both depression and stimulation suggested. The primary aim of this study was to assess if dexmedetomidine inhibited the cellular response to hypoxia in rat carotid body glomus cells, the cells of the organs mediating acute hypoxic ventilatory response (AHVR). Additionally, we used a small sample of mice to assess if there was any large influence of subsedative doses of dexmedetomidine on AHVR.

Material and Methods

In the primary study, glomus cells isolated from neonatal rats were used to study the effect of 0.1 nM (n = 9) and 1 nM (n = 13) dexmedetomidine on hypoxia-elicited intracellular calcium [Ca2%]i influx using ratiometric fluorimetry. Secondarily, whole animal unrestrained plethysmography was used to study AHVR in a total of 8 age-matched C57BL6 mice, divided on successive days into two groups of four mice randomly assigned to receive sub-sedative doses of 5, 50, or 500 μg.kg-1 dexmedetomidine versus control in a crossover study design (total n = 12 exposures to drug with n = 12 controls).

Results

There was no effect of dexmedetomidine on the hypoxia-elicited increase in [Ca2%]i in glomus cells (a mean ± SEM increase of 95 ± 32 nM from baseline with control hypoxia, 124 ± 41 nM with 0.1 nM dexmedetomidine; P = 0.514). In intact mice, dexmedetomidine had no effect on baseline ventilation during air-breathing (4.01 ± 0.3 ml.g-1.min-1 in control and 2.99 ± 0.5 ml.g-1.min-1 with 500 μg.kg-1 dexmedetomidine, the highest dose; P = 0.081) or on AHVR (136 ± 19% increase from baseline in control, 152 ± 46% with 500 μg.kg-1 dexmedetomidine, the highest dose; P = 0.536).

Conclusion

Dexmedetomidine had no effect on the cellular responses to hypoxia. We conclude that it unlikely acts via inhibition of oxygen sensing at the glomus cell. The respiratory chemoreflex effects of this drug remain an open question. In our small sample of intact mice, hypoxic chemoreflex responses and basal breathing were preserved.

Dexmedetomidine versus Propofol in Combination with Fentanyl for Sedation-Analgesia in Colonoscopy Procedures: A Randomized Prospective Study

BACKGROUND Colonoscopy is an uncomfortable and short procedure needing brief sedation with fast emergence. METHODS This research is going to measure intravenous dexmedetomidine against propofol-fentanyl combination in terms of sedation-analgesia and hemodynamic changes in non-obligatory colonoscopy procedures. 70 colonoscopy candidates aged between 20 to 70 years were enrolled in this study while separated into two random equal-sized groups (p stands for propofol- & D stands for dexmedetomidine groups). All patients were premedicated with 0.03 mg/kg midazolam and 1 µ/kg fentanyl, 10 minutes and 5 minutes before the colonoscopy process, respectively. 0.5-1 mg/kg propofol for the P group and 1 µ/kg dexmedetomidine for the D group were infused in one minute before the initiation of the procedure following by normal saline as maintenance liquid and boluses of 25-50 µg fentanyl as needed. RESULTS These variables were entered into a datasheet: hemodynamic changes, sedation-analgesia level throughout the procedure, and patients' and physicians' contentment. The mean arterial pressure changes were similar and insignificant in the two groups (82.44±12.34 vs. 87.63±22.45 p=0.2). The D group had lower heart rates in comparison with the P group (72.51±16.7 vs. 81.56±15.71 p=0.001). The P group was deeply to moderately sedated and required a significantly lower doses of fentanyl rescue treatment (71.02±25.63 vs. 91.45±38.62 µg p=0.003). The P group was associated with a high incidence of apnea and was significantly superior to the D group in the matter of satisfaction (43% against 77%). CONCLUSION Colonoscopists' contentment rates were identical in both groups. Propofol infusion is more satisfactory yet having more respiratory depression possibility in comparison with dexmedetomidine infusion in colonoscopy candidates.

Preintervention imaging and intraoperative management care of the hypertrophic obstructive cardiomyopathy patient

With an estimated overall mortality of less than 1 percent per year, hypertrophic cardiomyopathy, is the most common genetic cardiomyopathy. Intraoperative transesophageal echocardiography is the standard of care for assessing patients with hypertrophic obstructive cardiomyopathy undergoing surgical septal myectomy, allowing surgical planning, intraoperative hemodynamic monitoring, and postprocedural assessment of the repair, including detection of immediate complications. At various phases during surgical septal myectomy, the changing hemodynamic conditions may lead to worsening or improvement in left ventricle outflow tract obstruction by change in preload or afterload, systolic anterior motion of the mitral valve, or sympathetic stimulation. These characteristics represent unique challenges in the management of these patients, requiring a comprehensive understanding of the management of all the conditions required to decrease the left ventricle outflow tract gradient avoiding obstruction, which include the maintenance of sinus rhythm, adequate rate avoiding tachycardia and bradycardia, and avoidance of systemic hypotension preserving preload and afterload, with adequate vasoactive agents. The aim of this review is to summarize the perioperative assessment and management of patients undergoing hypertrophic obstructive myopathy surgery.

Effects of perioperative interventions for preventing postoperative delirium: A protocol for systematic review and meta-analysis of randomized controlled trials

BACKGROUND

Postoperative delirium (POD) not only increases the medical burden but also adversely affects patient prognosis. Although some cases of delirium can be avoided by early intervention, there is no clear evidence indicating whether any of these measures can effectively prevent POD in specific patient groups.

OBJECTIVE

The aim of this meta-analysis was to compare the efficacy and safety of the existing preventive measures for managing POD.

METHODS

The PubMed, OVID (Embase and MEDLINE), Web of Science, and the Cochrane Library databases were searched for articles published before January 2020. The relevant randomized controlled trials (RCTs) were selected based on the inclusion and exclusion criteria. Data extraction and methodological quality assessment were performed according to a predesigned data extraction form and scoring system, respectively. The interventions were compared on the basis of the primary outcome like incidence of POD, and secondary outcomes like duration of delirium and the length of intensive care unit and hospital stay.

RESULTS

Sixty-three RCTs were included in the study, covering interventions like surgery, anesthesia, analgesics, intraoperative blood glucose control, cholinesterase inhibitors, anticonvulsant drugs, antipsychotic drugs, sleep rhythmic regulation, and multi-modal nursing. The occurrence of POD was low in 4 trials that monitored the depth of anesthesia with bispectral index during the operation (P < .0001). Two studies showed that supplementary analgesia was useful for delirium prevention (P = .002). Seventeen studies showed that perioperative sedation with α2-adrenergic receptor agonists prevented POD (P = .0006). Six studies showed that both typical and atypical antipsychotic drugs can reduce the incidence of POD (P = .002). Multimodal nursing during the perioperative period effectively reduced POD in 6 studies (P < .00001). Furthermore, these preventive measures can reduce the duration of delirium, as well as the total and postoperative length of hospitalized stay for non-cardiac surgery patients. For patients undergoing cardiac surgery, effective prevention can only reduce the length of intensive care unit stay.

CONCLUSION

Measures including intraoperative monitoring of bispectral index, supplemental analgesia, α2-adrenergic receptor agonists, antipsychotic drugs, and multimodal care are helpful to prevent POD effectively. However, larger, high-quality RCTs are needed to verify these findings and develop more interventions and drugs for preventing postoperative delirium.

Circulating microRNA-30a-5p, microRNA-101-3p, microRNA-140-3p and microRNA-141-3p as potential biomarkers for dexmedetomidine response in pediatric patients

PURPOSE

The aim of this study was to investigate the expression levels of plasma miR-30a-5p, miR-101-3p, miR-140-3p and miR-141-3p and their relationship to dexmedetomidine efficacy and adverse effects in pediatric patients.

METHODS

The expression levels of miR-30a-5p, miR-101-3p, miR-140-3p and miR-141-3p were measured by qRT-PCR in plasma of 133 pediatric patients receiving dexmedetomidine for preoperative sedation. We analyzed the relationship between miRNA abundance and dexmedetomidine response, including sedative effect and adverse effects, and assessed the predictive power of miRNAs for drug response.

RESULTS

Among 133 pediatric patients, 111 patients were dexmedetomidine responders (UMSS ≥ 2) and 22 patients were non-responders (UMSS < 2). We observed higher expression levels of miR-101-3p and miR-140-3p in dexmedetomidine responders compared with non-responders (P < 0.05, P < 0.0001). In contrast, there was no significant difference in the expression levels of miR-30a-5p and miR-141-3p between responders and non-responders (P > 0.05). The plasma levels of miR-101-3p and miR-30a-5p were markedly downregulated in patients who experienced hypotension and bradycardia, respectively (P < 0.05). MiR-101-3p and miR-140-3p demonstrated a potential discriminatory ability between dexmedetomidine responders and non-responders, with AUC of 0.64 (P < 0.05) and 0.77 (P < 0.0001), respectively. The AUC of miR-101-3p in distinguishing patients without hypotension was 0.63 (P < 0.05). The AUC of miR-30a-5p in distinguishing patients without bradycardia was 0.74 (P < 0.05).

CONCLUSION

Our study demonstrated that circulating miR-101-3p, miR-140-3p and miR-30a-5p might be used as a blood-based marker for dexmedetomidine efficacy and safety in pediatric patients.

The 90% effective dose of intranasal dexmedetomidine for procedural sedation in children with congenital heart disease before and after surgery: A biased-coin design up-and-down sequential allocation trial

BACKGROUND

Intranasal dexmedetomidine can provide adequate sedation during short procedures. However, there are few reports investigating the effective dose of intranasal dexmedetomidine for sedation in children with congenital heart disease (CHD) before and after surgery.

METHODS

Children aged 13-36 months with acyanotic CHD requiring trans-thoracic echocardiography before cardiac surgery were recruited for this study. One month after the cardiac surgery, the same children were studied again. The 90% effective dose was established using a biased-coin design up-and-down sequential method. Onset time, examination time, wake-up time and adverse effects were measured. Safety was evaluated in terms of changes in vital signs.

RESULTS

A total of fifty-eight subjects were recruited for this study. The 90% effective dose of intranasal dexmedetomidine for sedation was 2.13 μg/kg (95% CI, 1.73-2.34 μg/kg) in children with CHD before cardiac surgery and 3.51 μg/kg (95% CI, 2.99-3.63 μg/kg) after cardiac surgery (P < .01). There were no differences between the groups in terms of demographic variables, onset time, examination time, wake-up time or adverse effects.

CONCLUSIONS

The 90% effective dose of intranasal dexmedetomidine for sedation in children with CHD was 2.13 μg/kg before cardiac surgery and 3.51 μg/kg after cardiac surgery.

Attenuation of the increase in intraocular pressure with dexmedetomidine: Systematic review with meta-analysis and trial sequential analysis

STUDY OBJECTIVE

Whether dexmedetomidine effectively attenuates the increase in intraocular pressure (IOP) remains inconclusive. We aim to evaluate the effects of dexmedetomidine on IOP in adult patients undergoing surgery which requires general anesthesia and endotracheal intubation.

DESIGN

Systematic review and meta-analysis.

INTERVENTIONS

Intravenous administration of dexmedetomidine during surgery.

MEASUREMENTS

Intraocular pressure.

METHODS

We searched PubMed, Embase, Scopus, Web of Science, Cochrane Library, Google Scholar, Wanfang Data, and China National Knowledge Infrastructure from the inception through April 14, 2020. Randomized control trials which involved adult patients undergoing surgery that required general anesthesia and endotracheal intubation, which compared intravenous administration of dexmedetomidine with placebo regarding the IOP levels, which also provided sufficient information for meta-analysis were considered eligible.

MAIN RESULTS

Twenty-nine randomized control trials were included. The IOP levels are significantly lower in patients receiving dexmedetomidine after the administration of dexmedetomidine [mean difference (MD), -2.04 mmHg; 95% confidence interval (CI), -2.40 mmHg to -1.67 mmHg], after the injection of succinylcholine (MD, -3.84 mmHg; 95% CI, -4.80 mmHg to -2.88 mmHg), after endotracheal intubation (MD, -3.64 mmHg; 95% CI, -4.46 mmHg to -2.82 mmHg), after pneumoperitoneum (MD, -3.12 mmHg; 95% CI, -3.93 mmHg to -2.30 mmHg), and after the patients being placed in a steep Trendelenburg position (MD, -4.12 mmHg; 95% CI, -5.39 mmHg to -2.85 mmHg). Trial sequential analyses for these outcomes are conclusive.

CONCLUSIONS

Dexmedetomidine effectively attenuates the increase in IOP levels, and should be considered especially for at-risk patients.

Dexmedetomidine-Associated Hyperpyrexia in Three Critically Ill Patients With Coronavirus Disease 2019

Objectives:

To present three patients with severe coronavirus disease 2019 infection who developed life-threatening hyperpyrexia while being treated with dexmedetomidine for sedation.

Data Sources:

Clinical records.

Study Selection:

Case report.

Data Extraction:

Relevant clinical information.

Data Synthesis:

We describe three patients, a 60-year-old female, 43-year-old female, and 46-year-old male, who were hospitalized in surge ICUs during the coronavirus disease 2019 pandemic in the early spring of 2020. All developed hyperpyrexia, defined as a temperature above 41.1°C, following an increase in dexmedetomidine dosing to above 1.5 µg/kg/hr. Fevers resolved following discontinuation of dexmedetomidine.

Conclusions:

While the exact mechanism of hyperpyrexia remains unclear, findings in this study suggest that high doses of dexmedetomidine infusion are associated with hyperpyrexia in a seemingly dose-dependent fashion in critically ill patients with coronavirus disease 2019. Coronavirus disease 2019 infection causes a hyperinflammatory state characterized by pro-inflammatory cytokine dysregulation. Dexmedetomidine, a centrally acting alpha-2 agonist, may alter hypothalamic temperature regulation through disturbances in neurotransmitter expression and metabolism. We postulate that the use of high-dose dexmedetomidine in a hyperinflammatory state may increase the risk of developing hyperpyrexia in this severe disease state.

Effect of Dexmedetomidine on Delirium in Elderly Surgical Patients: A Meta-analysis of Randomized Controlled Trials

OBJECTIVE

The purpose of this meta-analysis is to assess the effect of dexmedetomidine on delirium in elderly surgical patients.

DATA SOURCES

The Cochrane Library, Web of Science, PubMed, EMBASE, and Google Scholar were searched (January 1, 2000, to February 4, 2020) for randomized controlled trials (RCTs).

STUDY SELECTION AND DATA EXTRACTION

RCTs without language restrictions were included if delirium incidence was assessed in elderly surgical patients receiving dexmedetomidine. Intervention and basic information were extracted.

DATA SYNTHESIS

21 studies were included. Dexmedetomidine reduced delirium occurrence (risk ratio [RR] = 0.55; 95% CI = 0.45 to 0.67) in elderly surgical patients with sufficient evidence from trial sequential analysis. Dexmedetomidine did not prevent delirium incidence for cardiac surgery (RR = 0.71; 95% CI = 0.44 to 1.15) with insufficient evidence. Dexmedetomidine decreased mortality incidence (RR = 0.47; 95% CI = 0.25 to 0.89), shortened the length of intensive care unit (ICU; standard mean difference [SMD] = -0.46) and hospital stays (SMD = -0.41), and increased bradycardia incidence (RR = 1.60).

RELEVANCE TO PATIENT CARE AND CLINICAL PRACTICE

This review revealed that dexmedetomidine could reduce delirium incidence for elderly noncardiac surgical patients, and the effect of dexmedetomidine on delirium for elderly cardiac surgical patients needs further studies to guide clinicians.

CONCLUSION

Dexmedetomidine reduced delirium incidence in elderly surgical patients. The efficacy of dexmedetomidine on delirium for elderly cardiac surgical patients warrants further studies. Furthermore, dexmedetomidine was associated with an increased bradycardia incidence, shorter length of ICU/hospital stays, and a lower incidence of mortality.

Effects of various methods of dexmedetomidine administration for sedation in elderly patients undergoing spinal anesthesia: a randomized controlled study

Background

The purpose of this study was to investigate the degree of sedation and the incidence of adverse effects resulting from various methods of administering the initial dose followed by continuous infusion of dexmedetomidine (DEX) for sedation in elderly patients undergoing spinal anesthesia.

Methods

In total, 72 patients aged over 65 years who were to be administered spinal anesthesia were randomly allocated into three groups. The initial doses were injected to the groups as follows: group DD, DEX 0.5 μg/kg for 10 min; group MD, midazolam 0.02 mg/kg; and group D, no initial dose. This was followed immediately by infusing a maintenance dose of DEX 0.5 μg/kg/h to all groups.

Results

The Bispectral index (BIS) in the D group was significantly higher than in the other two groups. There were no significant differences in the Ramsay sedation scale (RSS) among the groups. The RSS 3 level was reached in 10 min from the start of sedation in MD and DD groups and in 20 min from the start of sedation in D group. Neither bradycardia nor hypotension was observed in any of the groups.

Conclusions

Patients in all three groups reached the RSS 3 sedating-effect level. However, the group that received continuous infusion only without the initial dose showed higher BIS than the other two groups and reached the RSS 3 later. No adverse events were observed in any of the groups.

[Comparison of ED50 of intranasal dexmedetomidine sedation in children with acyanotic congenital heart disease before and after cardiac surgery]

OBJECTIVE

To compare the median effective dose (ED50) of intranasal dexmedetomidine for procedural sedation in uncooperative pediatric patients with acyanotic congenital heart disease before and after cardiac surgery.

METHODS

We prospectively recruited 47 children (22 in preoperative group and 25 in postoperative group) who needed sedation for transthoracic echocardiography (TTE). A modified up-and-down sequential study design was employed to determine dexmedetomidine dose for each patient with a starting dose of 2 μg/kg in both groups; dexmedetomidine doses for subsequent subjects were determined according to the responses from the previous subject using the up-and-down method at a 0.25 μg/kg interval. The ED95 was determined using probit regression. The onset time, examination time, wake-up time and adverse effects were measured, and the safety was evaluated in terms of changes in vital signs every 5 min.

RESULTS

The ED50 value of intranasal dexmedetomidine for sedation was 1.84 μg/kg (95% CI: 1.68-2.00 μg/kg) in children with congenital heart disease before cardiac surgery, and 3.38 μg/kg (95% CI: 3.21-3.54 μg/kg) after the surgery. No significant difference was found between the two groups in the demographic variables, onset time, examination time, wake-up time, or adverse effects.

CONCLUSIONS

In children with acyanotic congenital heart disease, the ED50 of intranasal dexmedetomidine for TTE sedation increases to 3.38 μg/ kg after cardiac surgery from the preoperative value of 1.84 μg/kg.

Organ-Protective Effects and the Underlying Mechanism of Dexmedetomidine

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

Use of Dexmedetomidine in Transfemoral Transcatheter Aortic Valve Implantation (tf-TAVI) Procedures

INTRODUCTION

Dexmedetomidine is a highly selective alpha-2 adrenoreceptor agonist without any effect on the GABA receptor. Its sedative, anxiolytic, analgesic, and sympatholytic activities together with opioid-sparing effects make it suitable for short- and long-term sedation in the intensive care setting. We report our experience with dexmedetomidine use during transfemoral transcatheter aortic valve implantation (TAVI) procedure as an alternative to general anesthesia.

METHODS

This is a retrospective analysis of high-risk patients undergoing dexmedetomidine infusion for the transfemoral TAVI procedure between July 2017 and October 2019. The primary outcome parameters were hemodynamic: heart rate (HR), mean arterial pressure (MAP); respiratory oxygen saturation (SpO₂), pH, partial pressure of arterial oxygen (PaO₂), partial pressure of arterial carbon dioxide (PaCO₂), and sedation level (Richmond Agitation-Sedation Scale, RASS). The frequency of conversion to general anesthesia and the need for sedative "rescue therapy" were secondary endpoints. We also reported the overall anesthetic management and the incidence of intra- and postoperative complications.

RESULTS

Eighty-five patients were evaluated (age 81.58 ± 5.23 years, 36.5% men, 63.5% women). High comorbidity, according to the Society of Thoracic Surgeons Predicted Risk of Mortality (STS PROM). The patients' hemodynamic functions were kept normal. Complications such as cardiac arrest occurred in four patients; orotracheal intubation and cardiopulmonary resuscitation were necessary. Atrioventricular block occurred in nine patients. Respiratory parameters were maintained stable. Complications such as apnea, hypoventilation, and hypoxemia did not occur. All patients had RASS scores above or equal to 0 and - 1. No patient required rescue midazolam or fentanyl. No conversion to general anesthesia in patients sedated with dexmedetomidine was observed in the absence of hemodynamic complications caused by the surgical technique.

CONCLUSION

In this series, sedation with dexmedetomidine for TAVI procedures with femoral access was proven effective and safe. Dexmedetomidine may be a valid alternative to general anesthesia in high-risk older patients undergoing transfemoral TAVI.

Dexmedetomidine and Bupivacaine Association in Caudal Epidural Injection in Mares

The objective of the study was to compare the effects of caudal epidural bupivacaine and dexmedetomidine (DEX) combination, with bupivacaine or DEX plain for perineal analgesia in mares. Six healthy saddle mares weighing 330-370 kg and aged 10-15 years were used in this study. Each mare was assigned to receive three treatments: 0.04 mg/kg 0.25% bupivacaine (BP), 2 μg/kg DEX (DX), or 0.02 mg/kg bupivacaine and 1 μg/kg DEX (BPDX). The order of treatments was randomized. All drugs were injected into the caudal epidural space (Co1-Co2) through a 16-G Tuohy epidural needle. After the epidural injections, heart rate, respiratory rate, arterial blood pressures (systolic, diastolic, and mean), and rectal temperature were measured at 5, 10, 15, 30, 60, 90, and 120 minutes, and after this time, every 60 minutes until the end of the experiments. A subjective score system was used to assess analgesia, behavioral and motor blockade at the same time points. The BPDX treatment produced analgesic action with twice the duration (200 minutes) of the BP treatment (97 minutes), but with an analgesic duration shorter than the DX treatment (240 minutes) in the regions of the tail, perineum, and upper hind limbs in mares. All treatments showed mild motor blockade. No behavioral changes were observed in any of the animals. There was hemodynamic stability without significant changes in respiratory rate for all treatments. Epidural analgesia using DEX alone or the combination of DEX and bupivacaine may be an option for painful obstetric and gynecological procedures in mares.

Dexmedetomidine in Enhanced Recovery After Surgery (ERAS) Protocols for Postoperative Pain

PURPOSE OF REVIEW

Effective acute pain management has evolved considerably in recent years and is a primary area of focus in attempts to defend against the opioid epidemic. Persistent postsurgical pain (PPP) has an incidence of up to 30-50% and has negative outcome of quality of life and negative burden on individuals, family, and society. The 2016 American Society of Anesthesiologists (ASA) guidelines states that enhanced recovery after surgery (ERAS) forms an integral part of Perioperative Surgical Home (PSH) and is now recommended to use a multimodal opioid-sparing approach for management of postoperative pain. As such, dexmedetomidine is now being used as part of ERAS protocols along with regional nerve blocks and other medications, to create a satisfactory postoperative outcome with reduced opioid consumption in the Post anesthesia care unit (PACU).

RECENT FINDINGS

Dexmedetomidine, a selective alpha2 agonist, possesses analgesic effects and has a different mechanism of action when compared with opioids. When dexmedetomidine is initiated at the end of a procedure, it has a better hemodynamic stability and pain response than ropivacaine. Dexmedetomidine can be used as an adjuvant in epidurals with local anesthetic sparing effects. Its use during nerve blocks results in reduced postoperative pain. Also, local infiltration of IV dexmedetomidine is associated with earlier discharge from PACU. Perioperative use of dexmedetomidine has significantly improved postoperative outcomes when used as part of ERAS protocols. An in-depth review of the use of dexmedetomidine in ERAS protocols is presented for clinical anesthesiologists.

Pretreatment with dexmedetomidine alleviates lung injury in a rat model of intestinal ischemia reperfusion

The aim of the present study was to investigate the antioxidant mechanisms of dexmedetomidine against lung injury during intestinal ischemia reperfusion (IIR) in rats. The model of IIR-induced acute lung injury was established by occluding the superior mesenteric artery (SMA) for 1 h and reperfusing for 2 h using Sprague-Dawley rats. Pathological examination was used to assess the extent of the lung injury. Oxidative stress was evaluated by measuring malondialdehyde, myeloperoxidase and superoxide dismutase in the lung and plasma. The proinflammatory cytokines tumor necrosis factor-α and interleukin-6 were determined via an enzyme-linked immunosorbent assay. The mRNA and protein expression of nuclear factor-erythroid 2 related factor 2 (Nrf2) and heme oxygenase 1 (HO-1) were determined using a reverse transcription-quantitative polymerase chain reaction and western blotting. Pretreatment with dexmedetomidine significantly inhibited the oxidative stress response and proinflammatory factor release caused by IIR compared with the normal saline group (MDA and SOD in lung and plasma, P<0.05; MPO, IL-1β and TNF-α in lung and plasma, P<0.05). Dexmedetomidine improved pulmonary pathological changes in IIR rats compared with the normal saline group. Investigations into the molecular mechanism revealed that dexmedetomidine increased the expression levels of Nrf2 and HO-1 via activating α2 adrenergic receptors compared with the normal saline group. The antagonism of α2 adrenergic receptors may reverse the protective effect of dexmedetomidine on lung injury during IIR, including decreasing the expression levels of Nrf2 and HO-1, elevating the oxidative stress response and increasing the proinflammatory factor release. In conclusion, pretreatment with dexmedetomidine demonstrated protective effects against lung injury during IIR via α2 adrenergic receptors. The Nrf2/HO-1 signaling pathway may serve a function in the protective effect of dexmedetomidine.

The role of the endogenous neurotransmitters associated with neuropathic pain and in the opioid crisis: The innate pain-relieving system

Neuropathic pain is a chronic pain caused by central and peripheral nerve injury, long-term diabetes or treatment with chemotherapy drugs, and it is dissimilar to other chronic pain conditions. Chronic pain usually seriously affects the quality of life, and its drug treatment may result in increased costs of social and medical care. As in the USA and Canada, in Europe, the demand for pain-relieving medicines used in chronic pain has also significantly increased, but most European countries are not experiencing an opioid crisis. In this review, the role of various endogenous transmitters (noradrenaline, dopamine, serotonin, met- and leu-enkephalins, β-endorphin, dynorphins, cannabinoids, ATP) and various receptors (α₂, μ, etc.) in the innate pain-relieving system will be discussed. Furthermore, the modulation of pain processing pathways by transmitters, focusing on neuropathic pain and the role of the sympathetic nervous system in the side effects of excessive opioid treatment, will be explained.

Dexmedetomidine Sedation for Paroxysmal Supraventricular Tachycardia Ablation Is Not Associated With Alteration of Arrhythmia Inducibility

BACKGROUND

Dexmedetomidine (Dex) is an attractive agent for procedural sedation due to its unique pharmacodynamic profile, specifically affording predictable sedation without concurrent respiratory depression. However, Dex has previously been reported to prevent or terminate arrhythmias. The purpose of this study was to investigate paroxysmal supraventricular tachycardia (PSVT) inducibility and homeostatic stability during electrophysiology studies (EPSs) and ablation when a standardized Dex protocol was used as the primary sedation agent.

METHODS

We performed a retrospective review of 163 consecutive procedures for PSVT ablation that received Dex as the primary sedative with adjunct fentanyl and midazolam boluses (DEX-FENT-MIDAZ). This cohort was compared to 163 consecutive control procedures wherein strictly fentanyl and midazolam were used for sedation. The primary outcome reviewed was PSVT inducibility assessed before ablation. Reviewed secondary outcomes included level of sedation and intraprocedure hemodynamics and oxygenation.

RESULTS

The arrhythmia profiles of the DEX-FENT-MIDAZ and control cohorts were very similar. The overall incidence of a "negative" EPSs in which arrhythmia was not induced was 24% in the DEX-FENT-MIDAZ group and 26% in the control group (P = .7). Unintended deep sedation was significantly less with DEX-FENT-MIDAZ (4.3% vs 27%; P ≤ .0001). However, DEX-FENT-MIDAZ use was associated with a higher incidence of intraprocedure hypotension.

CONCLUSIONS

Dex sedation during EPSs is not associated with a reduction in PSVT inducibility. The therapeutic utility of Dex during EPS arises from the predictable sedation Dex affords but is associated with an increased incidence of intraprocedure hypotension.

Sole use of dexmedetomidine for sedation and analgesia in patients undergoing endovenous thermal ablation for incompetent saphenous veins

Background

Dexmedetomidine have both sedative and analgesic properties without respiratory-depressant effect. This study aims to evaluate the safety and effectiveness of sedation and analgesia using dexmedetomidine for the endovenous treatment of varicose veins.

Methods

This study included 88 patients (male =38, female =50; mean age, 48.7 years) who underwent endovenous laser or radiofrequency ablation of saphenous vein. At the beginning of sedation, dexmedetomidine was administered intravenously to all patients with a loading dose of 1 µg/kg over 15 minutes, which was followed by a maintenance dose of 0.2 µg/kg/h throughout the procedure. Peripheral oxygen saturation, systolic and diastolic blood pressure, heart rate and respiratory rate, and the induction and recovery time were assessed. The degree of pain was recorded by using a 10-point visual analog scale after the procedure. Adverse events associated with sedation/analgesia were also recorded.

Results

Eighty-five patients responded adequately to sole use of dexmedetomidine. The mean induction time was 17.5 minutes. The mean visual analog scale pain score during the procedure was 2.3±2.0. Maximum pain scores of 4 (discomforting) or less were recorded in 69 (78.4%) patients. Six (6.8%) patients complained of pain scores in excess of 7. Systolic and diastolic blood pressure and heart rate drop between 0 and 15 minutes were 18.2/9.3 mmHg and 13.5 beat/min, respectively. Three (3.5%) patients required cessation of infusion due to significant decrease in of blood pressure or heart rate. There was no hypoxic or resuscitation event during the procedures.

Conclusions

Dexmedetomidine can provide excellent sedative and analgesic effect during endovenous thermal ablation.

Use of dexmedetomidine in pediatric cardiac anesthesia

PURPOSE OF REVIEW

In recent years, ultrafast-track anesthesia with on-table extubation and concepts of accelerated postoperative care have gained increasing support in pediatric congenital cardiac surgery. It is believed that such approaches might ideally combine economic benefits with a striving for continuous improvement of patient outcomes. The present review summarizes the role of dexmedetomidine (DEX) in this setting.

RECENT FINDINGS

DEX is a clinical multipurpose drug that mediates its diverse responses through the activation of α2-adrenoreceptors. In pediatric cardiac surgery it has various applications. Used as a premedication, DEX provides arousable sedation and anxiolysis. As an intraoperative adjunctive agent of balanced general anesthesia the primary objectives for its administration are attenuation of the neuro-humoral stress response and facilitation of early extubation. During ICU treatment DEX spares opioids, prevents the risk of postoperative delirium or emergence agitation and impacts on important patient-centered outcomes, such as duration of mechanical ventilation, restart of enteral nutrition or length of ICU stay.

SUMMARY

Due to a favorable mix of beneficial physiologic actions and a limited adverse effect profile, DEX is established in the perioperative pediatric cardiac surgery setting. However, evidence from high-quality randomized controlled trials on the effects of supplemental DEX on meaningful patient outcomes is scarce, and research on the role of DEX in providing cardioprotection, neuroprotection, or renoprotection is still at its beginning. DEX has developed to one of the main agents in the armamentarium of cardiac anesthesiologists and pediatric intensivists, but it should not be regarded as the new 'magic bullet'.

Sedation Strategies for Procedures Outside the Operating Room

With the rapid development of diagnostic and therapeutic procedures performed outside the operating room (OR), the need for appropriate sedation care has emerged in importance to ensure the safety and comfort of patients and clinicians. The preparation and administration of sedatives and sedation care outside the OR require careful attention, proper monitoring systems, and clinically useful sedation guidelines. This literature review addresses proper monitoring and selection of sedatives for diagnostic and interventional procedures outside the OR. As the depth of sedation increases, respiratory depression and cardiovascular suppression become serious, necessitating careful surveillance using appropriate monitoring equipment.

Dexmedetomidine and sufentanil combination versus sufentanil alone for postoperative intravenous patient-controlled analgesia: a systematic review and meta-analysis of randomized controlled trials

BACKGROUND

Previous studies have demonstrated that dexmedetomidine improves the quality of postoperative analgesia. In the present study, we performed a meta-analysis of randomized controlled trials to quantify the effect of dexmedetomidine as an adjuvant to sufentanil for postoperative patient-controlled analgesia (PCA).

METHODS

PubMed, Embase, the Cochrane Library, and Web of Science were systematically searched for randomized controlled trials in which dexmedetomidine was used as an adjuvant for PCA with sufentanil. In the retrieved studies, we quantitatively analyzed pain intensity, sufentanil consumption, and drug-related side effects.

RESULTS

Nine studies with 907 patients were included in this meta-analysis. Compared with sufentanil alone, dexmedetomidine-sufentanil for postoperative intravenous PCA reduced pain intensity at 24 h (mean difference (MD) = - 0.70points; 95% confidence interval (CI): - 1.01, - 0.39; P < 0.00001) and 48 h postoperatively (MD = -0.61points; 95% CI: - 1.00, - 0.22; P = 0.002). Moreover, dexmedetomidine-sufentanil reduced sufentanil consumption during the first 24 h (MD = -13.77 μg; 95% CI: - 18.56, - 8.97; P < 0.00001) and 48 h postoperatively (MD = -20.81 μg; 95% CI: - 28.20, - 13.42; P < 0.00001). Finally, dexmedetomidine-sufentanil improved patient satisfaction without increasing the incidence of side effects.

CONCLUSIONS

Dexmedetomidine as an adjuvant to sufentanil for postoperative PCA can reduce postoperative pain score and sufentanil consumption.

The Efficacy and Safety of Dexmedetomidine Combined with Bupivacaine on Caudal Epidural Block in Children: A Meta-Analysis

BACKGROUND This meta-analysis was conducted to evaluate the analgesics effect and safety of dexmedetomidine (DEX) combined with bupivacaine (BU) on caudal epidural block. MATERIAL AND METHODS Published studies were identified using the PubMed, EMBASE, Web of Science, and the Cochrane Library from inception until October 2017. Relative risk (RR), the standardized mean difference (SMD), and the corresponding 95% confidence interval (CI) were calculated using the STATA 12.0. RESULTS Ten randomized controlled trials (RCTs) were selected for this meta-analysis, involving a total of 691 patients. There was a longer duration of postoperative analgesia in children receiving DEX (SMD=3.19, 95% CI: 2.16-4.22, P<0.001). Furthermore, there was a lower number of patients requiring rescue analgesics in the (BU) + (DEX) group (6 hours: RR=0.09, 95% CI: 0.05-0.17, P<0.001; 12 hours: RR=0.50, 95% CI: 0.32-0.79, P=0.003; 24 hours: RR=0.66, 95% CI: 0.51-0.85, P=0.002). Finally, the occurrence of adverse events, between BU and DEX + BU group, was not statistically significant (RR=0.96, 95% CI: 0.58-1.58, P>0.05). CONCLUSIONS DEX seems to be a promising adjuvant to BU increase duration of caudal analgesia without an increase in side effects in children. However, the result may be influenced by clinical heterogeneity. More large-scale, multicenter, approaching, double-blinded RCTs are required to confirm our results.

Effects of anesthesia on cerebral blood flow, metabolism, and neuroprotection

Administration of anesthetic agents fundamentally shifts the responsibility for maintenance of homeostasis from the patient and their intrinsic physiological regulatory mechanisms to the anesthesiologist. Continuous delivery of oxygen and nutrients to the brain is necessary to prevent irreversible injury and arises from a complex series of regulatory mechanisms that ensure uninterrupted cerebral blood flow. Our understanding of these regulatory mechanisms and the effects of anesthetics on them has been driven by the tireless work of pioneers in the field. It is of paramount importance that the anesthesiologist shares this understanding. Herein, we will review the physiological determinants of cerebral blood flow and how delivery of anesthesia impacts these processes.

Effect of intrathecal dexmedetomidine on preventing shivering in cesarean section after spinal anesthesia: a meta-analysis and trial sequential analysis

Objective

Intrathecal dexmedetomidine (DEX) has been used to prevent shivering in patients undergoing cesarean section. The aim of this meta-analysis was to evaluate whether intrathecal DEX could prevent shivering in cesarean section after spinal anesthesia.

Methods

We searched PubMed, Embase, Web of Science, and the Cochrane Library for randomized controlled trials (RCTs) comparing intrathecal DEX in cesarean section after spinal anesthesia with placebo and reporting on shivering, postoperative nausea and vomiting (PONV), hypotension, and bradycardia. Trial sequential analysis (TSA) was also carried out for RCTs comparing DEX with placebo. This meta-analysis has been registered on PROSPERO, and the registration number is CRD42017071640.

Results

Six randomized clinical trials comparing 360 patients were included in this study. Compared with placebo, intrathecal DEX significantly reduced the incidence of shivering (risk ratio [RR]=0.40; 95% CI [0.26, 0.62]; P<0.0001). No significant difference was found in the incidence of PONV (RR=1.34; 95% CI [0.82, 2.18]; P=0.24), hypotension (RR=1.09; 95% CI [0.84, 1.42]; P=0.50), or bradycardia (RR=1.55; 95% CI [0.54, 4.42]; P=0.42). However, no firm conclusions can be made based on the results of all outcomes according to the TSA.

Conclusion

This meta-analysis found that intrathecal DEX could prevent shivering in cesarean section after spinal anesthesia and did not induce PONV, hypotension, or bradycardia. However, firm conclusions cannot be made until more studies are conducted.

Conscious sedation with dexmedetomidine compared with asleep-awake-asleep craniotomies in glioma surgery: an analysis of 180 patients

OBJECTIVEAwake craniotomies have become a feasible tool over time to treat brain tumors located in eloquent regions. Different techniques have been applied in neurooncology centers. Both "asleep-awake-asleep" (asleep) and "conscious sedation" were used subsequently at the authors' neurosurgical department. Since 2013, the authors have only performed conscious sedation surgeries, predominantly using the α2-receptor agonist dexmedetomidine as the anesthetic drug. The aim of this study was to compare both mentioned techniques and evaluate the clinical use of dexmedetomidine in the setting of awake craniotomies for glioma surgery.METHODSThe authors retrospectively analyzed patients who underwent operations either under the asleep condition using propofol-remifentanil or under conscious sedation conditions using dexmedetomidine infusions. In the asleep group patients were intubated with a laryngeal mask and extubated for the assessment period. Adverse events, as well as applied drugs with doses and frequency of usage, were recorded.RESULTSFrom 224 awake surgeries between 2009 and 2015, 180 were performed for the resection of gliomas and included in the study. In the conscious sedation group (n = 75) significantly fewer opiates (p < 0.001) and vasoactive (p < 0.001) and antihypertensive (p < 0.001) drugs were used in comparison with the asleep group (n = 105). Furthermore, the postoperative length of stay (p < 0.001) and the surgical duration (p < 0.001) were significantly lower in the conscious sedation group.CONCLUSIONSUse of dexmedetomidine creates excellent conditions for awake surgeries. It sedates moderately and acts as an anxiolytic. Thus, after ceasing infusion it enables quick and reliable clinical neurological assessment of patients. This might lead to reducing the amount of administered antihypertensive and vasoactive drugs as well as the length of hospitalization, while likely ensuring more rapid surgery.

Dexmedetomidine in prevention and treatment of postoperative and intensive care unit delirium: a systematic review and meta-analysis

BACKGROUND

To determine the preventive and therapeutic effect of dexmedetomidine on intensive care unit (ICU) delirium.

METHODS

The literature search using PubMed and the Cochrane Central Register of Controlled Trials was performed (August 1, 2018) to detect all randomized controlled trials (RCTs) of adult ICU patients receiving dexmedetomidine. Articles were included if they assessed the influence of dexmedetomidine compared to a sedative agent on incidence of ICU delirium or treatment of this syndrome. Accordingly, relevant articles were allocated to the following two groups: (1) articles that assessed the delirium incidence (incidence comparison) or articles that assessed the treatment of delirium (treatment comparison). Incidence of delirium and delirium resolution were the primary outcomes. We combined treatment effects comparing dexmedetomidine versus (1) placebo, (2) standard sedatives, and (3) opioids in random-effects meta-analyses. Risk of bias for each included RCT was assessed following Cochrane standards.

RESULTS

The literature search resulted in 28 articles (25 articles/4975 patients for the incidence comparison and three articles/166 patients for the treatment comparison). In the incidence comparison, heterogeneity was present in different subgroups. Administration of dexmedetomidine was associated with significantly lower overall incidence of delirium when compared to placebo (RR 0.52; 95% CI 0.39-0.70; I² = 37%), standard sedatives (RR 0.63; 95% CI 0.46-0.86; I² = 69%), as well as to opioids (RR 0.61; 95% CI 0.44-0.83; I² = 0%). Use of dexmedetomidine significantly increased the risks of bradycardia and hypotension. Limited data were available on circulatory insufficiency and mortality. In the treatment comparison, the comparison drugs in the three RCTs were placebo, midazolam, and haloperidol. The resolution of delirium was measured differently in each study. Two out of the three studies indicated clear favorable effects for dexmedetomidine (i.e., compared to placebo and midazolam). The study comparing dexmedetomidine with haloperidol was a pilot study (n = 20) with high variability in the results.

CONCLUSION

Findings suggest that dexmedetomidine reduces incidence and duration of ICU delirium. Furthermore, our systematic searches show that there is limited evidence if a delirium shall be treated with dexmedetomidine.