Effects of Intravenous Dexmedetomidine in Humans

Dexmedetomidine as an Adjunctive Sedative in Patients Undergoing Endoscopic Submucosal Dissection: A Systematic Review and Meta-Analysis

Introduction

Endoscopic submucosal dissection (ESD) is a technique for removing dysplastic lesions in the gastrointestinal tract but carries risks like pain and perforation. Dexmedetomidine, an α2-receptor agonist, offers potential benefits as an adjunct sedative during ESD by providing anxiolysis and analgesia. This systematic review and meta-analysis assesses its efficacy and safety.

Methodology

We searched databases including Embase, Medline/PubMed, Scopus, and Web of Science up to April 21, 2024, following PRISMA guidelines. Eligible studies used dexmedetomidine with other sedatives for ESD. We analyzed outcomes such as en-bloc and complete resection rates, sedation duration, and adverse events, using RevMan for meta-analysis with a random-effects model.

Results

The initial search retrieved 216 studies and after screening, eight studies were included in the final analysis. Dexmedetomidine showed no significant difference in en-bloc or complete resection rates compared to controls. Sedation and procedure times were similar between the two groups as well. Dexmedetomidine significantly reduced restlessness (OR 0.15, 95% CI:0.07 to 0.29) and increased bradycardia (OR 7.15, 95% CI 3.17 to 16.11) compared to controls. Upon subgroup analysis, Dexmedetomidine plus Propofol, and Dexmedetomidine plus Midazolam, revealed the same findings regarding restlessness and bradycardia compared to controls which confirmed the adjunctive effects of Dexmedetomidine.

Conclusion

Dexmedetomidine as an adjunctive sedative appears safe and effective in ESD, reducing restlessness without significant adverse events. The risk of bradycardia is increased, which may be reflective of reduced physiological stress. Future studies should explore optimal dosing and compare Dexmedetomidine with other sedatives in diverse populations.

Dexmedetomidine and surgical field visibility in nasal surgery: A systematic review and meta-analysis

INTRODUCTION

Nasal and sinus surgery, especially using endoscopy, relies upon adequate haemostasis to be safe and effective. Often other haemostatic methods, such as cautery are not viable, and other methods must be employed. This study examines the effectiveness of dexmedetomidine in controlled hypotension and for surgical field visibility in endoscopic sinus surgery and other nasal surgeries.

REVIEW METHODS

A literature search was conducted in PubMed, Scopus, CINAHL and Central for randomised controlled trials using dexmedetomidine for controlled hypotension in adult patients undergoing endoscopic sinus surgery or other nasal surgery. Meta-analysis of mean differences and single means were performed.

RESULTS

Of 935 identified studies, 31 met the inclusion criteria. A statistically significant difference in Fromme-Boezaart surgical field visibility scores was found comparing dexmedetomidine to placebo (p < 0.00001) and propofol (p < 0.0001), but not other agents. A significant difference in intraoperative blood loss volume was found compared with placebo (51.5mL, p < 0.00001) and propofol (13.6mL, p < 0.0001), but not other agents.

CONCLUSION

Dexmedetomidine demonstrated significantly improved surgical field visibility and blood loss volume compared with placebo and propofol, but not other agents. Dexmedetomidine is viable and useful for controlled hypotension in nasal surgery. Choice of controlled hypotension agent should follow patient and procedure-specific considerations.

Optimizing Pediatric Sedation: Evaluating Remimazolam and Dexmedetomidine for Safety and Efficacy in Clinical Practice

Daily, children undergo countless investigations and interventions, which require sedation and immobilization to ensure safety and accuracy. This remains associated with a persistent risk of sedation-induced life-threatening events as children are particularly vulnerable to adverse medical events and complications. Consequently, there is an urgent need to increase the safety of pediatric sedation and anesthesia. An ideal approach involves the use of drugs with fewer intrinsic side effects. In this context, on the basis of their pharmacokinetic properties, remimazolam (RMZ) and dexmedetomidine (DEX) were evaluated for their suitability as ideal sedatives. RMZ and DEX, both of which are currently available in pediatric medicine, have shown great promise in initial publications. To date, only very limited data concerning RMZ in small children are available. RMZ is a novel, ultrashort-acting benzodiazepine that is metabolized by tissue esterase, largely independent of organ function. It has a context-sensitive half-life of approximately 10 min, with minimal accumulation even with prolonged use. Its effects can be completely reversed with flumazenil. DEX, an isomer of medetomidine, is a potent α2-receptor-agonist with multiple indications in anesthesia and intensive care medicine. It has coanalgesic potential, allows for 'arousal sedations' and has a low profile for cardiorespiratory side effects. DEX is metabolized in the liver and is predominantly excreted renally. Both drugs show potential in the prevention and treatment of delirium, with DEX having additional neuroprotective effects. DEX and RMZ possess several properties of an optimal sedative, including clinically insignificant main metabolites and a broad dosage range, indicating their potential to reduce the incidence of sedation-related life-threatening events in children. However, further clinical research is necessary to better evaluate their potential risks.

Co-administration of dexmedetomidine with total intravenous anaesthesia in carotid endarterectomy reduces requirements for propofol and improves haemodynamic stability: A single-centre, prospective, randomised controlled trial

BACKGROUND

Total intravenous anaesthesia guided by electroencephalography and neurophysiological monitoring may be used for carotid endarterectomy. Reduction of brain metabolic demand during cross-clamping of the internal carotid artery with propofol titrated to burst suppression requires effect-site concentrations that may delay emergence and interfere with intraoperative neurophysiological monitoring.

OBJECTIVE

To test the hypothesis that dexmedetomidine decreases the effect-site concentration of propofol required for burst-suppression in patients undergoing carotid endarterectomy.

DESIGN

Randomised controlled trial.

PARTICIPANTS

Patients undergoing carotid endarterectomy.

SETTING

University Hospital of Berne, Switzerland, from October 2018 to September 2024.

INTERVENTIONS

Patients were randomised into a control ( n  = 23) and a dexmedetomidine groups ( n  = 22). Total intravenous anaesthesia was administered to both groups. Patients in the dexmedetomidine group received an intravenous bolus of dexmedetomidine (0.4 μg kg -1 over 10 min) before induction, followed by a continuous intravenous infusion (0.4 μg kg -1  h -1 ). The effect-site concentrations of propofol were titrated against frontal electroencephalography parameters. Burst suppression was induced with propofol during cross-clamping of the internal carotid artery.

OUTCOME MEASURES

The primary outcome was the effect-site concentration of propofol required for burst-suppression. The secondary outcomes were the requirement for vasoactive substances, neurophysiological monitoring parameters, and postoperative delirium.

RESULTS

The effect-site concentration of propofol required for burst suppression was 4.0 μg ml -1 [3.50 to 4.90] (median [interquartile range]) in the dexmedetomidine group compared with 6.0 μg ml -1 [5.5 to 7.3] in the control group ( P  < 0.001). Less norepinephrine was required in the dexmedetomidine group (total 454 μg [246 to 818] compared with 1000 μg [444 to 1326] ( P  = 0.015) in the control group). Dexmedetomidine did not affect intraoperative neurophysiological monitoring.

CONCLUSION

Co-administration of dexmedetomidine to total intravenous anaesthesia for carotid endarterectomy decreased the effect-site concentrations of propofol required for burst suppression by 33%. The propofol-sparing effect and peripheral alpha-agonism of dexmedetomidine may explain the reduced requirement for vasopressors.

TRIAL REGISTRATION

Clinicaltrials.gov identifier: NCT04662177.

Dexmedetomidine for analgesia and sedation for procedural pain or discomfort in newborn infants

OBJECTIVES

This is a protocol for a Cochrane Review (intervention). The objectives are as follows: To assess the benefits and harms of dexmedetomidine compared with opioids, non-opioids and placebo in providing sedation and analgesia for procedural pain in newborn infants.

Randomized controlled trial on effect of different routes of dexmedetomidine on Haemodynamics in patients undergoing saphenectomy under epidural anaesthesia

The effect of epidural infusion of dexmedetomidine on haemodynamics is unclear. This study aimed to explore the effects of epidural or intravenous infusion of dexmedetomidine on haemodynamics during lower extremity varicose veins surgery (saphenectomy) under epidural anaesthesia. Ninety patients were randomly allocated to three groups: ED group (epidural: 0.59% ropivacaine plus 0.5 µg/kg dexmedetomidine, intravenous: normal saline), VD group (epidural: 0.59% ropivacaine plus normal saline, intravenous: 0.5 µg/kg dexmedetomidine), or NS group (epidural: 0.59% ropivacaine plus normal saline, intravenous: normal saline). The primary outcome was the systolic blood pressure (SBP) at before anaesthesia (T0) and at 5 (T1), 15 (T2), and 30 min (T3) and 1 (T4), 2 (T5), 4 (T6), 6 (T7), and 8 h (T8) after dexmedetomidine infusion. The secondary outcomes were diastolic blood pressure (DBP) and heart rate (HR) at T0 - 8, plasma norepinephrine (NE), myocardial oxygen consumption (MVO2) and anesthesia efficacy. Adverse reactions and other general data were also recorded. Compared with those in the NS group, the SBP at T3 - 7 and DBP at T4 - 5,7 were significantly lower in the ED group (P = 0.008, 0.001, 0.001, 0.001, 0.038 and P = 0.017, 0.006, 0.044, respectively), and the SBP and DBP at T1 - 8 were lower in the VD group (P < 0.001, 0.001, 0.001, 0.001, 0.004 and P < 0.001, 0.001, 0.001, 0.002, 0.001, 0.001, 0.001, 0.036, respectively). The SBP and DBP at T1 - 2 in the ED group were greater than those in the VD group (P = 0.021, 0.01 and P = 0.001, 0.011, respectively). The HR at T3 - 4,6-7 was lower in the ED group than in the NS group (P < 0.001, 0.021, 0.002, 0.004, respectively). Compared with that in the VD group, the HR in the ED group at T7 was significantly lower (P < 0.001). Anaesthesia efficiency was improved in the ED group compared with VD and NS groups. The incidence of hypotension was lower in the ED group than in the VD group (P = 0.003). The combination of 0.5 µg/kg dexmedetomidine and 0.59% ropivacaine for epidural anaesthesia provides more stable haemodynamics with a lower incidence of hypotension and improved efficiency of epidural anaesthesia in patients undergoing saphenectomy.

The effect of dexmedetomidine vs. atracurium on intubation condition in children - a randomized clinical trial

BACKGROUND

Using neuromuscular blocking agents (NMBA) in pediatric induction protocol is a challenging matter. Therefore, in this study, we aimed to find a safer way for anesthesia in children. We compared the effects of dexmedetomidine with atracurium on intubation conditions in children aged 6-12 years under general anesthesia. If dexmedetomidine has the similar effect as atracurium, we can use it for intubation and anesthesia of children in situations where the use of atracurium is challenging for any reason.

METHODS

This clinical trial was carried out on children between 6 and 12 years in Mashhad University of Medical Sciences, Mashhad, Iran between January 2018 and February 2020. Participants candidates for tracheal intubation and general anesthesia were enrolled. Patients were distributed into two groups: Patients received Dexmedetomidine (Group D) and patients received Atracurium (Group A).

RESULTS

We enrolled 25 patients in each group. Most of them were male. The intubation quality score consists of 5 items including laryngoscopy, vocal cord, coughing, jaw relaxation and limb movement was assessed between two groups. This score had no statistically significant difference between study groups. Immediately after induction and one minute after it, heart rate was statistically significant higher in group A than group D (P < 0.001 & P = 0.04 respectively). All of the intubations in our study were successful. More coughing was seen in group A compared with group D (P = 0.01).

CONCLUSION

In children aged 6-12 years, the administration of intravenous dexmedetomidine 1mcg/kg over a period of 10 min before the induction of anesthesia with sufentanil 0.3 µg/kg and propofol 3 mg/kg showed no statistically significant difference in quality of intubation score when compared to the use of 0.5 mg/kg atracurium to facilitate intubation. Decreased heart rate and less coughing were observed when using dexmedetomidine. This trial was registered retrospectively in the Iranian Clinical Trials Registry at 2021-24-05 ( https://www.irct.ir/ ), and its registration number is IRCT20201028049177N1.

Intranasal Dexmedetomidine for the Management of Preoperative Anxiety-Related Insomnia: A Randomized, Three-Blinded, Clinical Trial Compared with Lorazepam and Placebo

Purpose

To evaluate the efficacy and safety of intranasal dexmedetomidine (Dex), oral lorazepam, and a placebo in managing preoperative anxiety-related insomnia.

Patients and Methods

A total of 90 patients exhibiting symptoms of preoperative anxiety and insomnia were randomly assigned to three groups: Dex (receiving 2.5 µg/kg Dex intranasally and starch tablets orally), lorazepam (receiving saline intranasally and 2 mg lorazepam orally), and placebo (receiving saline intranasally and starch tablets orally). Interventions were conducted the night before surgery. The primary outcome was measured using the Leeds Sleep Evaluation Questionnaire (LSEQ) to evaluate changes in sleep quality pre- and post-intervention. Secondary outcomes included monitoring sleep on the night of the intervention, sleep satisfaction scores, changes in vital signs within 2 hours post-intervention, and adverse reaction rates.

Results

According to sleep assessments using the LSEQ, the Dex group demonstrated significant improvements in ease of getting to sleep (GTS), ease of awakening (AFS), and alertness and behavior after waking (BFW) compared to the lorazepam group (p < 0.05). However, no significant differences were observed in the quality of sleep (QOS) between the two groups (p > 0.05). Sleep monitoring indicated that the Dex group had a median sleep onset latency (SOL) of 19.0 min, significantly shorter than those recorded for the lorazepam group at 33.5 min and the placebo group at 57.0 min (p < 0.001). The total sleep time (TST) and sleep efficiency (SE) were 403.7 min and 84.5% for the Dex group, similar to the lorazepam group (408.6 min, 83.2%)(p >0.999) and superior to the placebo group (278.8 min, 57.4%)(p < 0.001). Sleep satisfaction scores did not significantly differ between the Dex and lorazepam groups (p > 0.999). No serious adverse reactions were reported across the groups.

Conclusion

Both 2.5 μg/kg intranasal Dex and 2 mg oral lorazepam effectively improved sleep quality in patients with preoperative anxiety-related insomnia. While both treatments were comparable in maintaining sleep, intranasal Dex was more effective in initiating sleep and enhancing daytime functionality than lorazepam.

Effect of low-dose dexmedetomidine to prolong spinal anesthesia in elderly patients: a prospective randomized controlled study

BACKGROUND

Spinal anesthesia for transurethral resection of the prostate (TURP) has a short duration, which poses challenges for postoperative pain management. The present study aimed to investigate the effects of intravenous (IV) dexmedetomidine at a dosage of 0.4 µg/kg in prolonging the duration of spinal anesthesia and minimizing postoperative pain in elderly patients undergoing TURP.

METHODS

This prospective randomized controlled trial enrolled 38 patients aged 60-80 years who underwent elective TURP with spinal anesthesia. The patients were randomly assigned to two treatment groups: Group D received IV 0.4 µg/kg dexmedetomidine, whereas Group C received IV normal saline after spinal anesthesia administration. The primary outcome was the time to 2-dermatome regression.

RESULTS

The 2-dermatome regression time was longer in Group D than in Group C (104.44 ± 16.97 min vs. 80.63 ± 15.59 min, p < 0.05). The peak sensory block levels were significantly higher in Group D [T7 (T6-T8)] than in Group C [T10 (T7-T10)] (p = 0.017). The incidence of hypotension and bradycardia and postoperative pain at 0, 6, 12, and 24 h were not different between two groups.

CONCLUSION

Intravenous dexmedetomidine at a dosage of 0.4 µg/kg significantly prolongs the duration of spinal sensory blockade. Although postoperative analgesia was not different, it provided hemodynamic stability without increasing the side effects.

Dexmedetomidine as an Adjunctive Sedative in Patients Undergoing Endoscopic Submucosal Dissection: A Systematic Review and Meta-Analysis

Introduction

Endoscopic submucosal dissection (ESD) allows for curative en-bloc resection of dysplastic gastrointestinal (GI) tract lesions. However, it is associated with postoperative adverse events (AEs) such as pain, bleeding, and perforation. Dexmedetomidine, an α2-receptor agonist, has emerged as a promising adjunct sedative for ESD under moderate sedation, offering anxiolysis and analgesia. We conducted a systematic review and meta-analysis to evaluate its efficacy and safety for use in ESD.

Methods

A comprehensive systematic search was conducted across multiple databases, including Embase, Medline, Scopus, and Web of Science. Studies that involved ESD utilizing dexmedetomidine as an adjunctive medication in combination with other sedatives, were included. Data extraction and risk of bias assessment were independently performed by two reviewers. Meta-analysis was carried out with RevMan using a random-effects model.

Results

Eight studies were included in the final analysis. Dexmedetomidine showed no significant difference in en-bloc or complete resection rates compared to controls. Sedation and procedure times were similar between the two groups as well. Dexmedetomidine significantly reduced restlessness (OR 0.15, 95% CI:0.07 to 0.29) and increased bradycardia (OR 7.15, 95% CI 3.17 to 16.11) compared to controls. Upon subgroup analysis, Dexmedetomidine plus Propofol, and Dexmedetomidine plus Midazolam, revealed the same findings regarding restlessness and bradycardia compared to controls which confirmed the adjunctive effects of Dexmedetomidine.

Conclusions

Dexmedetomidine as an adjunctive sedative appears safe and effective in ESD, reducing restlessness without significant adverse events. The risk of bradycardia is increased, which may be reflective of reduced physiological stress. Future studies should explore optimal dosing and compare Dexmedetomidine with other sedatives in diverse populations.

Ropivacaine versus ropivacaine plus dexmedetomidine in serratus anterior plane block patients undergoing post-thoracotomy surgery: a randomized, double-blinded clinical trial

BACKGROUND

This study was designed and implemented to investigate the addition of dexmedetomidine to Serratus Anterior Plane Block (SAP) with ropivacaine in reducing pain in patients undergoing post-thoracotomy surgery.

METHODS

This study included patients classified as American Society of Anesthesiology (ASA) Physical Status II, with a body mass index (BMI) under 40, who were undergoing thoracotomy at Imam Khomeini Hospital in Ahvaz. The subjects were randomly divided into two groups using a randomized controlled trial design. After surgery, in the recovery room, SAP was performed for patients with ropivacaine (0.4 ml/kg of 0.2% ropivacaine solution) (group R) and ropivacaine plus dexmedetomidine (0.5 μg/kg) (group RD). Pain (with verbal rating scale, VNRS), blood pressure (systolic, diastolic, and mean arterial pressure (MAP)), heart rate (HR), and blood oxygen saturation (O2 sat) were measured and recorded before the intervention, and 1, 6, 12, 24, and 48 h after the intervention.

RESULTS

Finally, 74 patients were included in this study. Both groups exhibited significant pain reduction at one hour, with sustained pain relief observed in the RD group at 6, 12, and 24 h (P < 0.001). The RD group also showed having lower values HR and MAP at 6 and 12 h (P < 0.001). Patients in the RD group received painkillers faster (P = 0.005) and required lower total narcotic usage (P < 0.0001). Two RD group patients experienced transient bradycardia, which resolved without treatment.

CONCLUSION

The findings of this study show that SAP block with dexmedetomidine is an effective and safe drug along with ropivacaine as a nerve-blocking agent in thoracotomy candidates.

Usefulness of deep sedation with intravenous dexmedetomidine and midazolam in cardiac catheterization procedures for pediatric patients

Background

Dexmedetomidine (DEX) is a highly selective alpha 2 receptor agonist that has the advantage of causing less respiratory depression than other sedative agents. We evaluated the add-on effects of DEX on sedation among pediatric patients who received midazolam and pentazocine during cardiac catheterization.

Methods

120 cardiac catheterization procedures in 110 patients under deep sedation at Department of Pediatrics, Kanazawa University Hospital from January 2013 to August 2018: 63 procedures without DEX (i.e., non-DEX group) and 57 procedures with DEX (i.e., DEX group). Intravenous midazolam and pentazocine were used in both groups, and DEX without an initial loading dose (0.6 μg/kg/h) was used in the DEX group. We retrospectively investigated complications during catheterization, doses of sedative agents, and changes in vital signs.

Results

Hypoxemia requiring oxygen administration during catheterization tended to be higher in the non-DEX group than in the DEX group (4.8% vs. 0%). Additional dose of midazolam was significantly lower in the DEX group (median [IQR]: 0.05 mg/kg [0-0.11]) than in the non-DEX group [0.09 mg/kg (0-0.23), p = 0.0288]. The additional dose of midazolam in the non-DEX group with hypoxemia was significantly higher than the dose used in the non-DEX group without hypoxemia. No case of bradycardia below the criteria for bradycardia occurred and no serious complications occurred in the DEX group.

Conclusion

The use of intravenous DEX in combination with midazolam and pentazocine in pediatric cardiac catheterization may reduce the need for an additional dose of midazolam and may contribute to the prevention of airway complications associated with respiratory depression caused by sedative agents.

The optimal dose of dexmedetomidine as a 0.59% ropivacaine adjuvant for epidural anesthesia in great saphenous varicose vein surgery, based on hemodynamics and anesthesia efficacy: a randomized, controlled, double-blind clinical trial

Objective

This study aimed to explore the optimal dose of dexmedetomidine as a 0.59% ropivacaine adjuvant for epidural anesthesia on perioperative hemodynamics and anesthesia efficacy in patients undergoing great saphenous varicose vein surgery.

Methods

A total of 90 patients were randomly divided into three groups: 0.25 μg/kg dexmedetomidine combined with 0.59% ropivacaine epidural infusion group (ED1 group), 0.5 μg/kg dexmedetomidine combined with 0.59% ropivacaine epidural infusion group (ED2 group), and 0.75 μg/kg dexmedetomidine combined with 0.59% ropivacaine epidural infusion group (ED3 group). Hemodynamics, anesthesia efficiency, and adverse reactions were recorded.

Main results

Compared with the ED1 group, the ED2 group had lower systolic blood pressure at T1-3 (T1, 95%CIs, 6.52-21.93, p < 0.001; T2, 95%CIs, 2.88-18.21, p = 0.004; T3, 95%CIs, 0.49-18.17, p = 0.035), and the diastolic blood pressure at T1-2 was decreased (T1, 95%CIs, 4.55-14.36, p < 0.001; T2, 95%CIs, 0.37-12.17, p = 0.033). Compared with the ED2 group, the ED3 group had higher systolic blood pressure at T1-2 (T1, 95%CIs, 5.90-21.46, p < 0.001; T2, 95%CIs, 2.07-17.55, p = 0.008) and higher diastolic blood pressure at T1-3 (T1, 95%CIs, 2.91-12.81, p = 0.001; T2, 95%CIs, 1.32-13.23, p = 0.011; T3, 95%CIs, 0.14-11.52, p = 0.043). Compared with the ED2 group, the heart rate was significantly decreased at T1-4 in the ED3 group (T1, 95%CIs, 2.25-15.72, p = 0.005; T2, 95%CIs, 2.35-13.82, p = 0.003; T3, 95%CIs, 0.50-9.79, p = 0.025; T4, 95%CIs, 1.46-10.36, p = 0.005). The myocardial oxygen consumption in all three groups was significantly decreased at each time point compared to T0 (p < 0.05 or < 0.001), and no significant between-group differences were detected (P>0.05). Compared with the ED1 group, the anesthesia efficiency of ED2 and ED3 groups was markedly enhanced, but the risk of bradycardia in ED2 and ED3 groups was dramatically increased (6 of 28 [21.4%] vs. 14 of 30 [46.7%] and 14 of 27 [51.9%], p = 0.023), one patient in the ED3 group experienced difficulty urinating, and remaining adverse reactions were mild in all three groups.

Conclusion

A measure of 0.5 μg/kg dexmedetomidine is the optimal dose as a 0.59% ropivacaine adjuvant for epidural anesthesia in patients undergoing great saphenous varicose vein surgery.

Clinical trial registration

http://www.chictr.org.cn/, registration number: ChiCTR2200060619.

Comparison of safety of general anesthesia and intravenous sedation during third-molar extraction surgery

This study compared the safety of general anesthesia (GA) and intravenous sedation (IVS) in patients who underwent extraction of one or more third molars. Data from 1260 patients (GA group, n = 1043; IVS group, n = 217) were retrospectively analyzed, including demographics, preoperative data, intraoperative hemodynamic parameters (blood pressure, heart rate, and oxygen saturation level), and medications administered intraoperatively and postoperatively. The incidence of intraoperative circulatory variations, surgery and anesthesia durations, postoperative complications, and medication use were assessed and compared. The GA group had longer anesthesia and surgery durations, a higher incidence of hypotension, and a higher frequency of postoperative analgesic use than the IVS group. Dexmedetomidine was the most frequently used sedative agent. The IVS group had a lower incidence of intraoperative hypotension but they had a higher need for vasopressors in the recovery room. Both anesthesia methods maintained satisfactory oxygen saturation levels and sufficient anesthesia throughout the procedure, but they showed different characteristics regarding the duration of surgery and anesthesia duration, hemodynamic stability, and postoperative analgesic needs. IVS may be preferable for patients at risk of cardiovascular complications such as hypotension or tachycardia during surgery.

Comparison of two different doses of dexmedetomidine for continuous epidural analgesia for lower limb surgeries: A randomized double-blind study

Background and Aims

Bolus epidural dexmedetomidine provides potent analgesia but the incidence of hemodynamic instability is high. There are only a few studies that have evaluated the efficacy of epidural dexmedetomidine infusion but none of them compared different doses to find the optimum safe dose. We compared the analgesic efficacy and safety of two different doses of dexmedetomidine in continuous epidural for postoperative analgesia.

Material and Methods

Patients undergoing lower limb surgeries were divided randomly into two groups: Group I (n = 36) received an epidural infusion of 0.1% ropivacaine + 0.5 μg/kg/24 h of dexmedetomidine and Group II (n = 36) received epidural infusion 0.1% ropivacaine + 1 μg/kg/24 h of dexmedetomidine. Both groups received epidural infusion at the rate of 5 ml/h over 48 h postoperatively. Pain scores, demand for rescue analgesics, hemodynamic parameters, and sedation scores were compared between the groups. Statistical analysis was done using an independent t-test and Chi-square test.

Results

1 μg/kg group (Group II) had a significantly reduced pain score at all time intervals and less demand for rescue analgesia (P = 0.03). The severity of pain was more in the 0.5 μg/kg group (Group I), at all times (P = 0.000). Incidence hypotension was higher in Group II. Bradycardia was seen in two patients in Group II and none in Group I.

Conclusion

Dexmedetomidine in a dose of 1 μg/kg/24 h with 5 ml of 0.1% ropivacaine through epidural infusion provides better analgesia with a safe hemodynamic profile.

Intravenous Bolus of Dexmedetomidine for Treatment of Severe Shivering After Caesarean Delivery Under Combined Spinal-Epidural Anaesthesia: A Randomized Dose-Response Study

Purpose

Shivering occurs frequently after caesarean delivery. The present study aimed to investigate the ED50 and ED95 of an intravenous (i.v.) bolus of dexmedetomidine for treating severe shivering after caesarean delivery under combined spinal-epidural anaesthesia.

Patients and methods

Seventy-five parturients with severe shivering after caesarean delivery were randomized into one of the five groups to receive an i.v. bolus of 0.2 (Group D1), 0.25 (Group D2), 0.3 (Group D3), 0.35 (Group D4) or 0.4 (Group D5) μg/kg of dexmedetomidine. Effectiveness of shivering treatment was defined as a standardized shivering score decreasing to ≤1 within 10 min of dexmedetomidine injection. The ED50 and ED95 were determined by probit regression. Adverse effects were also compared among the groups.

Results

The ED50 and ED95 of i.v. dexmedetomidine to treat severe shivering were 0.23 (95% CI, 0.16-0.26) μg/kg and 0.39 (95% CI, 0.34-0.52) μg/kg, respectively. No difference in the incidence of adverse effects was found between groups.

Conclusion

An i.v. bolus of 0.39 μg/kg of dexmedetomidine will treat 95% of parturients experiencing severe shivering after caesarean delivery.

Dexmedetomidine for analgesia and sedation in newborn infants receiving mechanical ventilation

BACKGROUND

Dexmedetomidine is a selective alpha-2 agonist with minimal impact on the haemodynamic profile. It is thought to be safer than morphine or stronger opioids, which are drugs currently used for analgesia and sedation in newborn infants. Dexmedetomidine is increasingly being used in children and infants despite not being licenced for analgesia in this group.

OBJECTIVES

To determine the overall effectiveness and safety of dexmedetomidine for sedation and analgesia in newborn infants receiving mechanical ventilation compared with other non-opioids, opioids, or placebo.

SEARCH METHODS

We searched CENTRAL, MEDLINE, Embase, CINAHL, and two trial registries in September 2023.

SELECTION CRITERIA

We planned to include randomised controlled trials (RCTs) and quasi-RCTs evaluating the effectiveness of dexmedetomidine compared with other non-opioids, opioids, or placebo for sedation and analgesia in neonates (aged under four weeks) requiring mechanical ventilation.

DATA COLLECTION AND ANALYSIS

We used standard Cochrane methods. Our primary outcomes were level of sedation and level of analgesia. Our secondary outcomes included days on mechanical ventilation, number of infants requiring additional medication for sedation or analgesia (or both), hypotension, neonatal mortality, and neurodevelopmental outcomes. We planned to use GRADE to assess the certainty of evidence for each outcome.

MAIN RESULTS

We identified no eligible studies for inclusion. We identified four ongoing studies, two of which appear to be eligible for inclusion; they will compare dexmedetomidine with fentanyl in newborn infants requiring surgery. We listed the other two studies as awaiting classification pending assessment of full reports. One study will compare dexmedetomidine with morphine in asphyxiated newborns undergoing hypothermia, and the other (mixed population, age up to three years) will evaluate dexmedetomidine versus ketamine plus dexmedetomidine for echocardiography. The planned sample size of the four studies ranges from 40 to 200 neonates. Data from these studies may provide some evidence for dexmedetomidine efficacy and safety.

AUTHORS' CONCLUSIONS

Despite the increasing use of dexmedetomidine, there is insufficient evidence supporting its routine use for analgesia and sedation in newborn infants on mechanical ventilation. Furthermore, data on dexmedetomidine safety are scarce, and there are no data available on its long-term effects. Future studies should address the efficacy, safety, and long-term effects of dexmedetomidine as a single drug therapy for sedation and analgesia in newborn infants.

Persistent Paradoxical Reaction to Midazolam despite General Anesthesia with Dexmedetomidine

Midazolam is a widely used benzodiazepine due to its rapid onset of action and relatively safe side effect profile. It is used for sedation, anxiolysis, and induction of general anesthesia. However, in <1% of instances, it may cause a paradoxical excitement: agitation, restlessness, myoclonus, stiffening of the limbs, and aggression. We report a case report in which preoperative administration of midazolam caused onset of the aforementioned symptoms that were not attenuated by general anesthesia with dexmedetomidine. This case report aims to create awareness about the rare adverse reactions of midazolam and prepare clinicians to manage these situations.

The feasibility of dexmedetomidine-led anesthesia maintenance strategy during major abdominal surgery

Background

Dexmedetomidine is known for its selective action on α2-adrenoceptor sites and is recognized for its neuroprotective capabilities. It can improve postoperative cognitive function. Commonly used anesthetics, such as sevoflurane and propofol, have been reported to affect postoperative cognitive function. Therefore, it could be valuable to explore dexmedetomidine-led anesthesia strategy. This study was designed to assess the performance, safety, and effective infusion rate in anesthesia maintenance, to explore a feasible dexmedetomidine-led anesthesia maintenance protocol, and to provide a foundation for potential combined anesthesia.

Methods

Thirty patients aged 18-60 years, classified as ASA I or II, undergoing abdominal surgery were involved. The anesthesia maintenance was achieved with dexmedetomidine, remifentanil and rocuronium. Dixon up-and-down sequential methodology was utilized to ascertain the ED50 of dexmedetomidine for maintaining Patient State Index (PSI) 25-40 (depth of stage III anesthesia). Intraoperative HR, BP and depth of anesthesia were monitored and controlled. The wake-up time from anesthesia, the incidence of intraoperative awareness and postoperative delirium, and the patients' satisfaction were assessed.

Results

The results indicated that dexmedetomidine-led anesthesia could maintain the depth of stage III anesthesia during abdominal surgery. The ED50 and ED95 of dexmedetomidine infusion rates during anesthesia maintenance were 2.298 μg/kg·h (95%CI: 2.190-2.404 μg/kg·h) and 3.765 μg/kg·h (95%CI: 3.550-4.050 μg/kg·h). Continuous infusion of dexmedetomidine and 0.1-0.3 μg/kg·min remifentanil could maintain PSI 25-40, and provide appropriate anesthesia depth for abdominal surgery. Perioperative bradycardia and hypertension could be rapidly corrected with atropine and nitroglycerin. The median wake-up time after anesthesia was 4.8 min, the perioperative maximum HR had significant correlation with wake-up time and intraoperative dexmedetomidine dose. No intraoperative awareness and postoperative delirium occurred; the patients were satisfied with dexmedetomidine-led anesthesia.

Conclusions

dexmedetomidine-led strategy could maintain stable depth of anesthesia throughout surgery, and the ED50 of dexmedetomidine infusion rates was 2.298 μg/kg·h. Intraoperative HR, BP and depth of anesthesia require monitoring, the bradycardia and hypertension could be rapidly corrected.

Effects of an intraoperative intravenous Bolus Dose of Dexmedetomidine on postoperative catheter-related bladder discomfort in male patients undergoing transurethral resection of bladder tumors: a randomized, double-blind, controlled trial

PURPOSE

To investigate whether the effect of intravenous bolus doses of dexmedetomidine on postoperative catheter-related bladder discomfort (CRBD) was dose-dependent in male patients undergoing transurethral resection of bladder tumors (TURBT).

METHODS

The study protocol was registered at the Chinese Clinical Trial Registry (ChiCTR 2,000,034,657, date of registration: July 14, 2020). Adult male patients were randomized to one of four groups: placebo (Group C); dexmedetomidine 0.2 µg/kg (Group D 0.2); dexmedetomidine 0.5 µg/kg (Group D 0.5); or dexmedetomidine 1 µg/kg (Group D 1). The primary outcome was the incidence of moderate-to-severe CRBD at 0, 1, 6, 24, and 48 h postoperatively.

RESULTS

The incidence of moderate-to-severe CRBD was significantly lower in Group D 0.5 and Group D 1 than in Group C at 0 h (13% vs. 40%, P = 0.006; 8% vs. 40%, P = 0.001), 1 h (15% vs. 53%, P < 0.001; 13% vs. 53%, P < 0.001), and 6 h (10% vs. 32%, P = 0.025; 8% vs. 32%, P = 0.009) postoperatively. Compared with baseline, both the MAP and HR were significantly lower in Group D 1 at 1 min ([94 ± 15] vs. [104 ± 13] mm Hg, P = 0.003; [64 ± 13] vs. [73 ± 13] bpm, P = 0.001) and 30 min ([93 ± 10] vs. [104 ± 13] mm Hg, P < 0.001; [58 ± 9] vs. [73 ± 13] bpm, P < 0.001) postextubation.

CONCLUSION

The effect of intravenous bolus doses of dexmedetomidine on postoperative CRBD was dose-independent, whereas intravenous administration of 0.5 µg/kg dexmedetomidine reduced the early postoperative incidence of CRBD with minimal side effects.

TRIAL REGISTRATION

Clinical trial number and registry URL: ChiCTR 2,000,034,657, http://www.chictr.org.cn , date of registration: July 14, 2020.

Comparison of remimazolam and dexmedetomidine for intraoperative sedation in patients undergoing lower extremity surgery under spinal anesthesia: a randomized clinical trial

BACKGROUND

Dexmedetomidine sedation has advantages, such as low incidence of respiratory depression and prolonged block duration, but also significant disadvantages, such as slow onset, high rate of sedation failure, and a long context-sensitive half-life. Remimazolam provides rapid sedation and recovery, high sedation efficacy and has minimal hemodynamic effects. We hypothesized that patients who received remimazolam would require less rescue midazolam than dexmedetomidine.

METHODS

Patients (n=103) scheduled for surgery under spinal anesthesia were randomized to receive dexmedetomidine (DEX group) or remimazolam (RMZ group) targeting a Modified Observer's Assessment of Alertness/Sedation score of 3 or 4. Rescue midazolam was administered if the patient failed to be sedated after the initial loading dose or despite infusion rate adjustment.

RESULTS

Rescue midazolam administration was significantly higher in the DEX group (0% vs 39.2%; p<0.001). Patients in the RMZ group reached the target sedation level more rapidly. The incidences of bradycardia (0% vs 25.5%; p<0.001) and hypertension (0% vs 21.6%; p<0.001) were higher in the DEX group. Respiratory depression occurred at a higher rate in the RMZ group (21.2% vs 2.0%; p=0.002), but no patients required manual ventilation. Patients in the RMZ group recovered faster, had a shorter PACU stay and higher satisfaction scores. Hypotensive episodes in the PACU were more frequent in the DEX group (1.9% vs 29.4%; p<0.001).

CONCLUSIONS

Remimazolam showed excellent sedation efficacy, minimal hemodynamic effects, and fewer adverse events in the PACU than dexmedetomidine. However, it is important to note that respiratory depression was more frequent with the use of remimazolam.

TRIAL REGISTRATION NUMBER

NCT05447507.

Effectiveness of dexmedetomidine during surgery under general anaesthesia on patient-centred outcomes: a systematic review and Bayesian meta-analysis protocol

INTRODUCTION

Dexmedetomidine is a promising pharmaceutical strategy to minimise opioid use during surgery. Despite its growing use, it is uncertain whether dexmedetomidine can improve patient-centred outcomes such as quality of recovery and pain.

METHODS AND ANALYSIS

We will conduct a systematic review and meta-analysis following the recommendations of the Cochrane Handbook for Systematic Reviews. We will search MEDLINE, Embase, CENTRAL, Web of Science and CINAHL approximately in October 2023. We will include randomised controlled trials evaluating the impact of systemic intraoperative dexmedetomidine on patient-centred outcomes. Patient-centred outcome definition will be based on the consensus definition established by the Standardised Endpoints in Perioperative Medicine initiative (StEP-COMPAC). Our primary outcome will be the quality of recovery after surgery. Our secondary outcomes will be patient well-being, function, health-related quality of life, life impact, multidimensional assessment of postoperative acute pain, chronic pain, persistent postoperative opioid use, opioid-related adverse events, hospital length of stay and adverse events. Two reviewers will independently screen and identify trials and extract data. We will evaluate the risk of bias of trials using the Cochrane Risk of Bias Tool (RoB 2.0). We will synthesise data using a random effects Bayesian model framework, estimating the probability of achieving a benefit and its clinical significance. We will assess statistical heterogeneity with the tau-squared and explore sources of heterogeneity with meta-regression. We have involved patient partners, clinicians, methodologists, and key partner organisations in the development of this protocol, and we plan to continue this collaboration throughout all phases of this systematic review.

ETHICS AND DISSEMINATION

Our systematic review does not require research ethics approval. It will help inform current clinical practice guidelines and guide development of future randomised controlled trials. The results will be disseminated in open-access peer-reviewed journals, presented at conferences and shared among collaborators and networks.

PROSPERO REGISTRATION NUMBER

CRD42023439896.

Severe Hypertensive Response to Atropine Therapy for Bradycardia Associated with Dexmedetomidine: Case Report and Literature Review

Dexmedetomidine is a selective and potent α2-adrenoceptor agonist used for sedation, analgesia, and anxiolysis, with minimal respiratory depression; therefore, it is widely used in clinical practice. Transient hypertension has been reported to be an indication for the use of dexmedetomidine. The authors report three female patients who experienced hypertensive crisis when used atropine to treat bradycardia caused by dexmedetomidine. The transient hypertension is a relatively common side effect of dexmedetomidine, hypertensive crisis seen with coadministration of atropine is much less frequently reported. This is the first report to describe the use of atropine to treat bradycardia induced by dexmedetomidine, which may cause severe hypertension in female patients. They discuss the reason for and treatment of hypertension caused by administration of atropine and dexmedetomidine together and review the relevant literature.

Clinical Use of Adrenergic Receptor Ligands in Acute Care Settings

In this chapter, we review how ligands, both agonists and antagonists, for the major classes of adrenoreceptors, are utilized in acute care clinical settings. Adrenergic ligands exert their effects by interacting with the three major classes of adrenoceptors. Adrenoceptor agonists and antagonists have important applications, ranging from treatment of hypotension to asthma, and have proven to be extremely useful in a variety of clinical settings of acute care from the operating room to the critical care environment. Continued research interpreting the mechanisms of adrenoreceptors may help the discovery of new drugs with more desirable clinical profiles.

Comparison of the effects of dexmedetomidine and propofol on the cardiovascular autonomic nervous system during spinal anesthesia: preliminary randomized controlled observational study

Spinal anesthesia induces sympatholysis and is usually combined with dexmedetomidine or propofol which induce different hemodynamic changes. The purpose of this study was to compare the effect on autonomic nervous system between dexmedetomidine and propofol combined with spinal anesthesia. Patients aged 20-65 undergoing elective surgery under spinal anesthesia were randomly assigned to dexmedetomidine or propofol group. Heart rate variability (HRV) and hemodynamic variables were measured at four time points: T0, baseline; T1, 10 min after spinal anesthesia; T2, 10 min after sedative administration; and T3, 20 min after sedative administration. In 59 patients, dexmedetomidine and propofol groups had significantly different hemodynamic changes over time (time × group effect P < 0.001). The dexmedetomidine group had slower heart rate at T2 (P = 0.001) and higher blood pressures at T2 and T3 (P < 0.001) than the propofol group. Overall HRV dynamics showed a significant change over time from T0 to T3, but both groups exhibited similar trends. Compared to the baseline data within the group, the low frequency (LF) decreased in both groups but the decrease occurred at T2 in the propofol group and at T3 in the dexmedetomidine group. The high frequency (HF) increased at T2 and T3 only in the dexmedetomidine group. The LF/HF ratio decreased in the dexmedetomidine group at T3. Dexmedetomidine showed slower heart rate and higher blood pressure than propofol when combined with spinal anesthesia, however, dexmedetomidine and propofol exhibited similar trends in HRV dynamics. Compared with the baseline within each group, both agents decreased LF, but only dexmedetomidine increased HF and decreased in the LF/HF ratio significantly.

Ventricular Tachycardia Following Ephedrine During Dexmedetomidine Dental Procedural Sedation

We present the case of a 46-year-old man who received ephedrine for hypotension after surgery for a mandibular lesion under intravenous (IV) moderate sedation with dexmedetomidine (DEX) and experienced transient ventricular tachycardia (VT). The patient was scheduled to have cystectomy and multiple apicoectomies for the mandibular periapical infection and the simple bone cyst. Other than obesity, snoring, and a nonalcoholic fatty liver, he denied any other significant medical history, medications, or allergies. The surgery was successful; however, his blood pressure dropped after stopping the DEX infusion. Ephedrine was administered IV several times, which resulted in the onset of VT on the electrocardiogram (ECG). His blood pressure could not be measured at the time, but he was able to respond and breathe independently. A defibrillator was immediately made available. The ECG revealed a spontaneous transition from VT to atrial fibrillation with ST depression. Because he was unable to revert to a normal sinus rhythm, the patient was transferred to a general hospital, where he underwent additional testing. No abnormalities were observed in his heart or brain. After DEX administration, its long-lasting alpha-2 adrenoceptor agonist effects can cause vasodilation and inhibition of sympathetic activity, leading to hypotension in some patients. Should that occur, ephedrine can be used to increase blood pressure, but it may also provoke transient coronary artery spasms and lead to VT. Consequently, extreme caution should be exercised in patients who develop hypotension following DEX administration. We also recognize the significance of regular training sessions, such as advanced cardiac life support programs.

A comparation of dexmedetomidine and midazolam for sedation in patients with mechanical ventilation in ICU: A systematic review and meta-analysis

BACKGROUND

The use of dexmedetomidine rather than midazolam may improve ICU outcomes. We summarized the available recent evidence to further verify this conclusion.

METHODS

An electronic search of PubMed, Medline, Embase, Cochrane Library, and Web of Science was conducted. Risk ratios (RR) were used for binary categorical variables, and for continuous variables, weighted mean differences (WMD) were calculated, the effect sizes are expressed as 95% confidence intervals (CI), and trial sequential analysis was performed.

RESULTS

16 randomized controlled trials were enrolled 2035 patients in the study. Dexmedetomidine as opposed to midazolam achieved a shorter length of stay in ICU (MD = -2.25, 95%CI = -2.94, -1.57, p<0.0001), lower risk of delirium (RR = 0.63, 95%CI = 0.50, 0.81, p = 0.0002), and shorter duration of mechanical ventilation (MD = -0.83, 95%CI = -1.24, -0.43, p<0.0001). The association between dexmedetomidine and bradycardia was also found to be significant (RR 2.21, 95%CI 1.31, 3.73, p = 0.003). We found no difference in hypotension (RR = 1.44, 95%CI = 0.87, 2.38, P = 0.16), mortality (RR = 1.02, 95%CI = 0.83, 1.25, P = 0.87), neither in terms of adverse effects requiring intervention, hospital length of stay, or sedation effects.

CONCLUSIONS

Combined with recent evidence, compared with midazolam, dexmedetomidine decreased the risk of delirium, mechanical ventilation, length of stay in the ICU, as well as reduced patient costs. But dexmedetomidine could not reduce mortality and increased the risk of bradycardia.

The effects of perioperative dexmedetomidine infusion on hemodynamic stability during laparoscopic adrenalectomy for pheochromocytoma: a randomized study

Introduction

Pheochromocytoma is a rare catecholamine-producing neuroendocrine tumor originating from the adrenal medulla chromaffin cells. Hemodynamic instability can occur during the induction of anesthesia and surgical manipulation of the tumor. This study investigated the effects of intraoperative dexmedetomidine administration on hemodynamic stability in patients undergoing laparoscopic adrenalectomy for pheochromocytoma.

Methods

Forty patients who underwent laparoscopic adrenalectomy for pheochromocytoma were randomly assigned to the dexmedetomidine (n = 20) or control (n = 20) group. The primary outcome of this study was intraoperative hemodynamic stability, and the secondary endpoint was the plasma catecholamine concentrations, specifically of epinephrine and norepinephrine.

Results

The intraoperative maximum blood pressures were significantly lower in the dexmedetomidine group (control vs. dexmedetomidine group: 182 ± 31 vs. 161 ± 20, 102 ± 17 vs. 90 ± 10, and 128 ± 22 vs. 116 ± 12 [mean ± SD] mmHg and p = 0.020, 0.015, and 0.040 for systolic, diastolic, and mean blood pressure, respectively). The maximum heart rate during surgery was 108 ± 15 bpm in the control group and 95 ± 12 bpm in the dexmedetomidine group (p = 0.010). Other parameters of hemodynamic instability were comparable between both groups. Plasma catecholamine concentrations did not differ between the groups.

Conclusion

Dexmedetomidine infusion following the induction of anesthesia at a rate of 0.5 μg/kg/h significantly attenuated the maximum intraoperative SBP, DBP, MBP, and HR, contributing to improved hemodynamic stability.

Hemodynamic instability following intravenous dexmedetomidine infusion for sedation under brachial plexus block: Two case reports

BACKGROUND

Dexmedetomidine (DMED) is frequently used as a sedative in several medical fields. The benefits of DMED include enhanced quality of regional anesthesia, prolonged analgesia, and postoperative opioid-sparing when administered intravenously or perineurally in combination with regional anesthesia. Severe hemodynamic complications, such as profound bradycardia and hypotension, can occur after DMED administration in critically ill patients or overdosage; however, there are few reports of complications with DMED administration following brachial plexus block (BPB).

CASE SUMMARY

We present two cases of hemodynamic instability that occurred following the initial loading of DMED under supraclavicular BPB. A healthy 29-year-old man without any medical history showed profound bradycardia after receiving a loading dose of DMED 0.9 μg/kg for 9 min. DMED administration was promptly stopped, and after receiving a second dose of atropine, the heart rate recovered. A 62-year-old woman with a history of cardiomyopathy became hypotensive abruptly, requiring the administration of inotrope and vasopressors after receiving a reduced loading dose of 0.5 μg/kg for 10 min. Half of the recommended loading dose of DMED was administered due to the underlying heart dysfunction. Decreased blood pressure was maintained despite the intravenous administration of ephedrine. With continuous infusion of dopamine and norepinephrine, the vital signs were maintained within normal ranges. Inotropic and vasopressor support was required for over 6 h after the initial loading dose of DMED.

CONCLUSION

DMED administration following BPB could trigger hemodynamic instability in patients with decreased cardiac function as well as in healthy individuals.

Dexmedetomidine in the Treatment of Depression: An Up-to-date Narrative Review

Depressive disorders (DD) are common, and their prevalence is expected to rise over the next decade. Depressive disorders are linked to significant morbidity and mortality. The clinical conundrum of depressive disorders lies in the heterogeneity of their phenomenology and etiology. Further, the currently available antidepressants have several limitations, including a delayed onset of action, limited efficacy, and an unfavorable side effect profile. In this review, Dexmedetomidine (DEX), a highly selective and potent α2-adrenergic receptor (α2-AR) agonist, is proposed as a potentially novel antidepressant with multiple mechanisms of action targeting various depression pathophysiological processes. These mechanisms include modulation of the noradrenergic system, regulation of neuroinflammation and oxidative stress, influence on the Brain-Derived Neurotrophic Factor (BDNF) levels, and modulation of neurotransmitter systems, such as glutamate. The review begins with an introduction before moving on to a discussion of DEX's pharmacological features. The pathophysiological and phenomenological targets of DD are also explored, along with the review of the existing preclinical and clinical evidence for DEX's putative anti-depressant effects. Finally, the review ends by presenting the pertinent conclusions and future directions.

Dexmedetomidine Improved Sleep Quality in the Intensive Care Unit After Laryngectomy

Purpose

To examine whether nighttime dexmedetomidine infusion improved sleep quality in patients after laryngectomy.

Patients and Methods

Thirty-five post-laryngectomy patients admitted to the intensive care unit (ICU) were randomly assigned to a 9-h (from 2100 h on surgery day to 0600 h the morning after laryngectomy) dexmedetomidine (0.3 μg/kg/h continuous infusion) or placebo group. Polysomnography results were monitored during the dexmedetomidine infusion period. The percentage of stage 2 non-rapid eye movement (stage N2) sleep was the primary outcome measure.

Results

Thirty-five patients (18 placebo group; 17 dexmedetomidine group) had complete polysomnogram recordings. The percentage of stage N3 sleep was significantly increased in the dexmedetomidine infusion group (from median 0% (0 to 0) in placebo group to 0% (interquartile range, 0 to 4) in dexmedetomidine group (difference, -2.32%; 95% CI, -4.19 to -0.443; P = 0.0167)). Infusion had no effect on total sleep time, stage N1 or N2 sleep percentages, or sleep efficiency. It decreased muscle tensity and snore non-rapid eye movement. Subjective sleep quality improved. Hypotension incidence increased in the dexmedetomidine group, but significant intervention was not required.

Conclusion

Dexmedetomidine infusion improved overall patient sleep quality in the ICU after laryngectomy.

A Comparison of the Sedative Effect of Dexmedetomidine and Midazolam on Patients Undergoing Gastrointestinal Endosonography Outside the Operating Room

Background

Patients may experience anxiety, discomfort, and pain during endoscopy, which cannot be tolerated without sedative drugs.

Objectives

This study aimed to compare the sedative effects of dexmedetomidine and midazolam on patients undergoing endosonography outside the operating room.

Methods

This randomized, double-blind clinical trial was conducted on 126 patients aged 18 - 65 years old with American Society of Anesthesiologists (ASA) physical status I - II undergoing elective endosonography. Patients were randomly divided into 2 groups. The dexmedetomidine group received dexmedetomidine (1 μg/kg) for 25 minutes with propofol (0.5 mg/kg) and fentanyl (1 μg/kg) at the start of the procedure. The midazolam group received midazolam (0.03 mg/kg) with propofol (0.5 mg/kg) and fentanyl (1 μg/kg). Heart rate, mean arterial pressure (MAP), and oxygen saturation (SpO2) were recorded before and 5, 10, and 15 minutes after starting the procedure. The Ramsay Sedation Scale (RSS) and the need for an additional dose of propofol were recorded during the procedure. The Numeric Pain Rating scale (Ambesh score) scores were recorded at the beginning, immediately after, and 1 hour after the procedure. Nausea and vomiting were assessed using the Visual Analogue Scale in cooperation with the patient.

Results

The dexmedetomidine group had significantly higher SpO2 and RSS scores during sedation than the midazolam group (P = 0.02). Overall, specialist satisfaction was higher in the dexmedetomidine group than in the midazolam group. There was no clinically significant difference in pain score and nausea and vomiting frequencies between the 2 groups.

Conclusions

Dexmedetomidine is more effective than midazolam for sedation during gastrointestinal endosonography.

Effect of mini-dose dexmedetomidine supplemented intravenous analgesia on sleep structure in older patients after major noncardiac surgery: A randomized trial

STUDY OBJECTIVES

In previous studies, low-dose dexmedetomidine supplemented opioid analgesia improved sleep architecture but increased sedation level. Herein we tested the hypothesis that mini-dose dexmedetomidine supplemented analgesia improves sleep structure without increasing sedation.

METHODS

In this randomized trial, 118 older patients (≥65 years) following major noncardiac surgery were randomized to receive patient-controlled intravenous analgesia supplemented with either placebo or dexmedetomidine (median 0.02 μg kg^-1 h^-1) for up to 3 days. Polysomnogram was monitored from 9:00 p.m. on the day of surgery until 6:00 a.m. on the first day after surgery. Our primary outcome was the percentage of non-rapid eye movement stage 2 (N2) sleep. Secondary outcomes included other sleep structure parameters during the night of surgery and the sedation score during the first five postoperative days.

RESULTS

All 118 patients completed the study; of these, 85 were included in sleep structure analysis. Dexmedetomidine supplemented analgesia increased the percentage of N2 sleep (median difference, 10%; 95% CI, 1%-20%; P = 0.03). It also prolonged total sleep time (median difference, 78 min; 95% CI, 21 to 143; P = 0.01), increased sleep efficiency (median difference, 14%; 95% CI, 4%-26%; P = 0.01), decreased percentage of N1 sleep (median difference, -10%; 95% CI, -20% to -1%; P = 0.04), and lowered sleep fragmentation index (median difference, -1.6 times⋅h^-1; 95% CI, -3.7 to 0.1; P = 0.04). Sedation score within 5 days did not differ between the two groups.

CONCLUSIONS

Supplementing intravenous analgesia with mini-dose dexmedetomidine improved sleep structure without increasing sedation in older patients recovering from major surgery.

CLINICAL TRIALS

www.

CLINICALTRIALS

gov (NCT03117790), registered 2 April 2017.

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

INTRODUCTION

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

METHODS AND ANALYSIS

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

ETHICS AND DISSEMINATION

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

TRIAL REGISTRATION NUMBER

NCT05168280.

Dexmedetomidine versus remifentanil for controlled hypotension under general anesthesia: A systematic review and meta-analysis

This meta-analysis aimed to analyze and compare the efficacy and safety of remifentanil and dexmedetomidine applied respectively for controlled hypotension under general anesthesia. We searched the Cochrane Library, PubMed, EMBASE, Web of Science, CNKI, SinoMed, Wanfang, and VIP databases, as well as dissertations and conference papers, to obtain randomized controlled trials comparing remifentanil and dexmedetomidine applied respectively for controlled hypotension before August 23, 2021. The primary outcomes included hemodynamic profiles, surgical field score, and blood loss. Extubation time, sedation and pain score at the PACU, and perioperative adverse events were the secondary outcomes. Nine randomized controlled trials with 543 patients (272 in the dexmedetomidine group and 271 in the remifentanil group) were eventually included. This meta-analysis indicated no significant difference between dexmedetomidine and remifentanil in terms of surgical field score, blood loss, minimum values of mean arterial pressure (MD 0.24 with 95% CI [-1.65, 2.13], P = 0.80, I2 = 66%) and heart rate (MD 0.42 [-1.33, 2.17], P = 0.64, I2 = 40%), sedation scores at the PACU (MD -0.09 [-0.69, 0.50], P = 0.76, I2 = 92%), and incidence of bradycardia (OR 2.24 [0.70, 7.15], P = 0.17, I2 = 0%). Compared with remifentanil, dexmedetomidine as the controlled hypotensive agent showed a lower visual analogue score at the PACU (MD -1.01 [-1.25, -0.77], P<0.00001, I2 = 0%) and incidence of shivering (OR 0.22 [0.08, 0.60], P = 0.003, I2 = 0%), nausea, and vomiting (OR 0.34 [0.13, 0.89], P = 0.03, I2 = 0%). However, extubation time was shorter in the remifentanil group (MD 3.34 [0.75, 5.93], P = 0.01, I2 = 90%). In conclusion, dexmedetomidine and remifentanil are both effective in providing satisfactory controlled hypotension and surgical conditions. Dexmedetomidine is better in easing postoperative pain at the PACU and reducing the occurrence of shivering, nausea, and vomiting. Meanwhile, remifentanil is a fast-track anesthesia with a shorter extubation time. Given the limitations of this meta-analysis, further studies are needed for a more definitive comparison of the efficacy and safety of dexmedetomidine and remifentanil.

Efficacy and safety of intranasal ketamine compared with intranasal dexmedetomidine as a premedication before general anesthesia in pediatric patients: a systematic review and meta-analysis of randomized controlled trials

PURPOSE

To compare the efficacy and safety of intranasal ketamine with intranasal dexmedetomidine as a premedication in pediatric patients undergoing general anesthesia for elective surgery or other procedures.

SOURCE

We conducted a systematic literature search in PubMed, PubMed Central, Scopus, LILACS, Google Scholar, the Cochrane Database of Systematic Reviews, and trial registries for randomized controlled trials (RCTs) comparing intranasal ketamine with intranasal dexmedetomidine as preanesthetic medication in elective surgery or other procedures in pediatric patients. We used Review Manager software version 5.4.1 for statistical analysis and adhered to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. We assessed the methodological quality of the included studies with the RoB 2 risk of bias tool. All outcomes were pooled using the Mantle-Haenszel method and a random-effects model. The quality of evidence was assessed using the GRADE approach.

PRINCIPAL FINDINGS

Out of 2,445 full texts assessed, we included ten RCTs in the analysis. The efficacy outcomes did not fulfill the comparability criteria between intranasal ketamine and intranasal dexmedetomidine for sedation at parental separation (risk ratio [RR], 0.90; 95% confidence interval [CI], 0.79 to 1.04; I2 = 89%; GRADE evidence, low), mask acceptance (RR, 0.86; 95% CI, 0.66 to 1.13; I2 = 50%; GRADE evidence, low), and iv canulation (RR, 1.16; 95% CI, 0.79 to 1.69; I2 = 69%; GRADE evidence, very low). Intranasal ketamine-treated patients showed a higher incidence of nausea and vomiting (RR, 2.47; 95% CI, 1.24 to 4.91; I2 = 0; GRADE evidence, moderate). Significantly more bradycardia was observed in the intranasal dexmedetomidine group (RR, 0.16; 95% CI, 0.04 to 0.70; I2 = 40%; GRADE evidence, moderate) than in the ketamine group.

CONCLUSION

The low to very low-quality evidence in this systematic review and meta-analysis of RCTs neither confirmed nor refuted comparable premedication efficacy of intranasal ketamine and dexmedetomidine in terms of parental separation, mask acceptance, and iv cannulation in a pediatric population. Clinical decision-making is likely to be influenced by differences in gastrointestinal and cardiovascular safety profiles.

STUDY REGISTRATION

PROSPERO (CRD42021262516); registered 22 July 2021.

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.

Prevention of Bradycardia during Spinal Anesthesia under Dexmedetomidine Sedation in Older Adults

Older adults exhibit reduced physiological responses to beta-adrenergic stimulation and parasympathetic inhibition. This study aimed to investigate the effect of reducing the incidence of bradycardia in the atropine and ephedrine pretreatment group compared to the control group in older adults who received spinal anesthesia with intravenous dexmedetomidine. Overall, 102 older adults aged over 65 years were randomly divided into three groups, and saline (control group), atropine at 0.5 mg (atropine group), and ephedrine at 8 mg (ephedrine group) were administered intravenously to each group as pretreatment. Immediately after spinal anesthesia, dexmedetomidine loading and study drug injections were commenced. The primary outcome was the incidence of bradycardia (<50 beats per min) within 60 min following dexmedetomidine loading. The incidence of bradycardia requiring atropine treatment was significantly higher in the control group than in the atropine and ephedrine groups (27.3% vs. 6.1% and 8.8%, respectively; p = 0.035), and no difference was noted between the atropine and ephedrine groups. Therefore, if ephedrine or atropine is selected and used according to the patient’s condition and clinical situation, it may be helpful in preventing bradycardia during spinal anesthesia using dexmedetomidine in older patients.

Midazolam versus Dexmedetomidine in Patients at Risk of Obstructive Sleep Apnea during Urology Procedures: A Randomized Controlled Trial

Benzodiazepines are the most commonly used sedatives for the reduction of patient anxiety. However, they have adverse intraoperative effects, especially in obstructive sleep apnea (OSA) patients. This study aimed to compare dexmedetomidine (DEX) and midazolam (MDZ) sedation considering intraoperative complications during transurethral resections of the bladder and prostate regarding the risk for OSA. This study was a blinded randomized clinical trial, which included 115 adult patients with a mean age of 65 undergoing urological procedures. Patients were divided into four groups regarding OSA risk (low to medium and high) and choice of either MDZ or DEX. The doses were titrated to reach a Ramsay sedation scale score of 4/5. The intraoperative complications were recorded. Incidence rates of desaturations (44% vs. 12.7%, p = 0.0001), snoring (76% vs. 49%, p = 0.0008), restlessness (26.7% vs. 1.8%, p = 0.0044), and coughing (42.1% vs. 14.5%, p = 0.0001) were higher in the MDZ group compared with DEX, independently of OSA risk. Having a high risk for OSA increased the incidence rates of desaturation (51.2% vs. 15.7%, p < 0.0001) and snoring (90% vs. 47.1%, p < 0.0001), regardless of the sedative choice. DEX produced fewer intraoperative complications over MDZ during sedation in both low to medium risk and high-risk OSA patients.

Applications of Dexmedetomidine in Palliative and Hospice Care

Although the use of dexmedetomidine is currently approved by the US Food and Drug Administration in the adult population for monitored anesthesia care and sedation during mechanical ventilation, clinical experience suggests the potential application of dexmedetomidine in the palliative care arena. The medication can provide sedation with lower risk of delirium, control or minimize the adverse effects of other medications, and augment analgesia from opioids. We conducted a computerized bibliographic search of the literature regarding dexmedetomidine use for the treatment of pain and provision of sedation during palliative and hospice care in adult and pediatric patients. The objective was to provide a general descriptive account of the physiologic effects of dexmedetomidine and review its potential applications in the field of palliative and hospice care in adult and pediatric patients. The sedative and analgesic effects of dexmedetomidine have been well studied in animal and human models. Published experience from both single case reports and small case series has demonstrated the potential therapeutic applications of dexmedetomidine in palliative and hospice care. In addition to intravenous administration, case reports have demonstrated its successful use by both the intranasal and subcutaneous routes. Although these experiences have suggested its safety and efficacy, larger series and additional clinical experience with prospective comparison to other agents are needed to further define its efficacy and role in palliative and hospice care.

Population Pharmacokinetics of Intranasal Dexmedetomidine in Infants and Young Children

BACKGROUND

Intranasal dexmedetomidine provides noninvasive, effective procedural sedation for pediatric patients, and has been widely used in clinical practice. However, the dosage applied has varied fourfold in pediatric clinical studies. To validate an appropriate dosing regimen, this study investigated the pharmacokinetics of intranasal dexmedetomidine in Chinese children under 3 yr old.

METHODS

Intranasal dexmedetomidine 2 µg · kg-1 was administered to children with simple vascular malformations undergoing interventional radiological procedures. A population pharmacokinetic analysis with data from an optimized sparse-sampling design was performed using nonlinear mixed-effects modeling. Clearance was modeled using allometric scaling and a sigmoid postmenstrual age maturation model. Monte Carlo simulations were performed to assess the different dosing regimens.

RESULTS

A total of 586 samples from 137 children aged 3 to 36 months were included in the trial. The data were adequately described by a two-compartment model with first-order elimination. Body weight with allometric scaling and maturation function were significant covariates of dexmedetomidine clearance. The pharmacokinetic parameters for the median subjects (weight 10 kg and postmenstrual age 101 weeks) in the authors' study were apparent central volume of distribution 7.55 l, apparent clearance of central compartment 9.92 l · h-1, apparent peripheral volume of distribution 7.80 l, and apparent intercompartmental clearance 61.7 l · h-1. The simulation indicated that at the dose of 2 µg · kg-1, 95% of simulated individuals could achieve a target therapeutic concentration of 0.3 ng · ml-1 within 20 min, and the average peak concentration of 0.563 ng · ml-1 could be attained at 61 min.

CONCLUSIONS

The pharmacokinetic characteristics of intranasal dexmedetomidine were evaluated in Chinese pediatric patients aged between 3 and 36 months. An evidence-based dosing regimen at 2 µg · kg-1 could achieve a preset therapeutic threshold of mild to moderate sedation that lasted for up to 2 h.

EDITOR’S PERSPECTIVE

Safety and efficacy of pentazocine–midazolam combination for pain and anxiety relief in radiofrequency ablation therapy for hepatocellular carcinoma

Background and Aim

Radiofrequency ablation (RFA) therapy is frequently used as first‐line treatment for small hepatocellular carcinoma (HCC). RFA is often associated with pain; however, no definitive solution has been established for its relief. We retrospectively analyzed the safety and efficacy of the combination of pentazocine and midazolam to relieve pain experienced by HCC patients undergoing RFA.

Methods

We studied 77 patients with 98 HCCs treated with RFA between January 2015 and August 2019. Patients were divided into two groups: the sedative‐free group, which included those who received pentazocine alone, and the pentazocine–midazolam group, which included those who received a combination of pentazocine and midazolam. The degrees of analgesia and sedation were evaluated using the numerical rating scale (NRS) and the Richmond Agitation‐Sedation Scale (RASS), respectively. Other parameters such as treatment time, awakening time, midazolam dosage, vital signs, local recurrence rate, and time to recurrence were also examined.

Results

The median NRS score and RASS score were significantly lower in the pentazocine–midazolam group. Ninety‐five percent of patients in the pentazocine–midazolam group had no memory of the RFA session. The treatment time and awakening time were prolonged for the pentazocine–midazolam group. No significant differences in oxygen saturation, recurrence rates, and time to local recurrence were observed between groups.

Conclusion

A combination of pentazocine and midazolam is safe and effective for pain and anxiety relief experienced by patients undergoing RFA for local treatment of HCC.

No Benefits of Adding Dexmedetomidine, Ketamine, Dexamethasone and Nerve Blocks to an Established Multimodal Analgesic Regimen after Total Knee Arthroplasty

BACKGROUND.

An optimal opioid-sparing multimodal analgesic regimen to treat severe pain can enhance recovery after total knee arthroplasty. We hypothesized that adding 5 recently described IV and regional interventions to multimodal analgesic regimen can further reduce opioid consumption.

METHODS.

In a double-blinded fashion, seventy-eight patients undergoing elective total knee arthroplasty were randomized to either (1) a control group (n=39) that received spinal anesthesia with intrathecal morphine, periarticular local anesthesia infiltration, IV dexamethasone and a single injection adductor canal block or (2) a study group (n=39) that received the same set of analgesic treatments plus 5 additional interventions - local anesthetic infiltration between the popliteal artery and capsule of the posterior knee, intraoperative IV dexmedetomidine and ketamine, and postoperatively, 1 additional IV dexamethasone bolus, and 2 additional adductor canal block injections. The primary outcome measure was 24-hour cumulative opioid consumption after surgery and secondary outcomes were other analgesic, patient recovery and functional outcomes and adverse events.

RESULTS.

Opioid consumption was not different between groups at 24 hours (oral morphine equivalents, mean ± SD), study: 23.7 ± 18.0 mg vs. control: 29.3 ± 18.7 mg; mean difference [95% CI], -5.6 mg [-2.7, 13.9]; P = 0.189) and all other time points after surgery. There were no major differences in pain scores, quality of recovery, or time to reach rehabilitation milestones. Hypotensive episodes occurred more frequently in the study group (25/39 (64.1%) vs. 13/39 (33.3%), p= 0.010).

CONCLUSIONS.

In the presence of periarticular local anesthesia infiltration, intrathecal morphine, single shot adductor canal block and dexamethasone, the addition of 5 analgesic interventions - local anesthetic infiltration between the popliteal artery and capsule of the posterior knee, IV dexmedetomidine, IV ketamine, an additional IV dexamethasone dose and repeated adductor canal block injections - failed to further reduce opioid consumption, pain scores or improve functional outcomes after total knee arthroplasty.

Minimizing Motion Artifacts in Intravital Microscopy Using the Sedative Effect of Dexmedetomidine

Among intravital imaging instruments, the intravital two-photon fluorescence excitation microscope has the advantage of enabling real-time 3D fluorescence imaging deep into cells and tissues, with reduced photobleaching and photodamage compared with conventional intravital confocal microscopes. However, excessive motion of organs due to involuntary movement such as breathing may result in out-of-focus images and severe fluorescence intensity fluctuations, which hinder meaningful imaging and analysis. The clinically approved alpha-2 adrenergic receptor agonist dexmedetomidine was administered to mice during two-photon fluorescence intravital imaging to alleviate this problem. As dexmedetomidine blocks the release of the neurotransmitter norepinephrine, pain is suppressed, blood pressure is reduced, and a sedation effect is observed. By tracking the quality of focus and stability of detected fluorescence in two-photon fluorescence images of fluorescein isothiocyanate-sensitized liver vasculature in vivo, we demonstrated that intravascular dexmedetomidine can reduce fluorescence fluctuations caused by respiration on a timescale of minutes in mice, improving image quality and resolution. The results indicate that short-term dexmedetomidine treatment is suitable for reducing involuntary motion in preclinical intravital imaging studies. This method may be applicable to other animal models.

Comparison of the Efficacy and Safety of Dexmedetomidine Administered in Two Different Modes Under Procedural Sedation and Analgesia in Plastic Surgery

Background

Dexmedetomidine (DEX), a highly selective α2-adrenergic receptor agonist, is now widely used in procedural sedation and analgesia. This study was designed to observe and compare the efficacy and safety of DEX administered in two different modes.

Methods

In total, 100 patients were randomly divided into two groups to receive intravenous DEX 1 µg/kg over 15 min followed by 0.4–0.7 µg/kg/h infusion or DEX 1 µg/kg over 30 min followed by 0.4–0.7 µg/kg/h infusion. Heart rate (HR), mean arterial pressure (MAP), respiratory rate (RR), bispectral index (BIS), Ramsay Sedation Scores (RSS scores), the lowest respiratory rates (LRR), incidences of respiratory adverse events and frequencies of body movements were recorded. Recovery time, recall of intraoperative events, pain scores in PACU and satisfaction of patients and surgeons were assessed.

Results

The BIS at time points from 5 min after anesthesia to the end of surgery in the intervention group were significantly higher (p < 0.05). The RSS scores at time points from 5 min after anesthesia to immediately after induction with DEX were significantly higher in the intervention group (p < 0.05). The HR at time points from the beginning of surgery to 30 min after local anesthesia, the MAP at time points from 30 min after local anesthesia to the end of surgery, and the RR at time points from 5 min after anesthesia to the end of surgery were significantly higher in the intervention group (p < 0.05). Patients in the intervention group had higher LRR, lower incidences of respiratory adverse events, and shorter recovery time (p < 0.05).

Conclusions

Dexmedetomidine infused with a loading dose over 30 min had less impact on patients’ hemodynamics and respiration and could shorten the recovery time after anesthesia in procedural sedation and analgesia.

Clinical Trial Registration

ClinicalTrials.gov, identifier: ChiCTR1900027958.

Dexmedetomidine-Induced Aortic Contraction Involves Transactivation of the Epidermal Growth Factor Receptor in Rats

In this study, we examined whether aortic contraction, induced by the alpha-2 adrenoceptor agonist dexmedetomidine, is involved in the transactivation of the epidermal growth factor receptor (EGFR) in isolated endothelium-denuded rat aortas. Additionally, we aimed to elucidate the associated underlying cellular mechanisms. The effects of the alpha-2 adrenoceptor inhibitor rauwolscine, EGFR tyrosine kinase inhibitor AG1478, Src kinase inhibitors PP1 and PP2, and matrix metalloproteinase inhibitor GM6001 on EGFR tyrosine phosphorylation and c-Jun NH2-terminal kinase (JNK) phosphorylation induced by dexmedetomidine in rat aortic smooth muscles were examined. In addition, the effects of these inhibitors on dexmedetomidine-induced contraction in isolated endothelium-denuded rat aorta were examined. Dexmedetomidine-induced contraction was inhibited by the alpha-1 adrenoceptor inhibitor prazosin, rauwolscine, AG1478, PP1, PP2, and GM6001 alone or by a combined treatment with prazosin and AG1478. AG1478 (3 × 10−6 M) inhibited dexmedetomidine-induced contraction in isolated endothelium-denuded rat aortas pretreated with rauwolscine. Dexmedetomidine-induced EGFR tyrosine and JNK phosphorylation were inhibited by rauwolscine, PP1, PP2, GM6001, and AG1478. Furthermore, dexmedetomidine-induced JNK phosphorylation reduced upon EGFR siRNA treatment. Therefore, these results suggested that the transactivation of EGFR associated with dexmedetomidine-induced contraction, mediated by the alpha-2 adrenoceptor, Src kinase, and matrix metalloproteinase, caused JNK phosphorylation and increased calcium levels.

Opioid-Free Labor Analgesia: Dexmedetomidine as an Adjuvant Combined with Ropivacaine

Background

Side effects of the use of opioid analgesics during painless delivery are the main factors that affect rapid postpartum recovery. Opioid use can result in dangerous respiratory depression in the patient. Opioids can also disrupt the baby's breathing and heart rate. The nonopioid analgesic dexmedetomidine, a new a2-adrenergic agonist, possesses higher selectivity, greater analgesic effects, and fewer side effects. Moreover, epidural administration of dexmedetomidine also reduces local anesthetic consumption.

Objective

Our study aims to compare the analgesic effects as well as the side effects of ropivacaine with dexmedetomidine against sufentanyl as an epidural labor analgesia.

Methods

This study is a randomized, double-blinded, controlled trial (registration no. ChiCTR2200055360) involving 120 primiparous (a woman who has given birth once), singleton pregnancy women who are greater than 38 weeks into gestation and have requested epidural labor analgesia. The participants were randomized to receive 0.1% ropivacaine with sufentanyl (0.4 μg/ml) or dexmedetomidine (0.4 μg/ml). The primary outcomes included Visual Analogue Score (VAS), duration of first epidural infusions, the requirement of additional PCEA bolus, and adverse reactions during labor analgesia.

Results

Of the 120 subjects who consented, 91 parturient women (women in the condition of labor) had complete data for analysis. Demographics and VAS, as well as maternal and fetal outcomes, were similar between the groups. The duration of first epidural infusions in dexmedetomidine was significantly longer than sufentanyl (median value: 115 vs 68 min, P < 0.01); the parturient women who received dexmedetomidine and who required additional PCEA bolus were fewer in comparison to those who received sufentanyl (27.5% vs 49.0%, P < 0.05). Furthermore, the incidence of pruritus in the dexmedetomidine group was lower in comparison to the sufentanyl group (0% vs 11.8%, P < 0.05).

Conclusions

Dexmedetomidine, a nonopioid, is superior to the opioid analgesic sufentanyl in providing a prolonged analgesic effect as an epidural during labor. It also reduces local anesthetic consumption and has fewer side effects. The trial is registered with ChiCTR2200055360.

No Difference between Spinal Anesthesia with Hyperbaric Ropivacaine and Intravenous Dexmedetomidine Sedation with and without Intrathecal Fentanyl: A Randomized Noninferiority Trial

To enhance the duration of single-shot spinal anesthesia, intrathecal fentanyl and intravenous dexmedetomidine are widely used as adjuvants to local anesthetics. This noninferiority trial evaluated whether hyperbaric ropivacaine alone can produce a noninferior duration of sensory block in comparison to hyperbaric ropivacaine with intrathecal fentanyl in patients under dexmedetomidine sedation. Methods. Fifty patients scheduled for elective lower limb surgery under spinal anesthesia were randomly assigned in a double-blind fashion to receive either hyperbaric ropivacaine 15 mg (Group R) or hyperbaric ropivacaine 15 mg with intrathecal fentanyl 20 μg (Group RF). Intravenous dexmedetomidine (1 μg/kg for 10 min, followed by 0.5 μg/kg/h) was administered in both groups. The primary outcome of this study was the time to two-dermatomal regression of sensory block. The noninferiority margin for the mean difference was -10 min. Characteristics of the block, intraoperative and postoperative side effects, postoperative pain score, and analgesic consumption were assessed as secondary outcomes. Results. There was no difference in the two-dermatomal regressions of sensory block between the two groups (Group R 70.4 ± 10.2 min, Group RF 71.2 ± 12.4 min, p = 0.804) with a mean difference of 0.8 min (-7.2 to 5.6, 95% confidence interval). Thus, the noninferiority of hyperbaric ropivacaine alone was established. There were no significant differences in the secondary outcomes between the two groups. Conclusions. Under intravenous dexmedetomidine sedation, the duration of spinal anesthesia with hyperbaric ropivacaine alone was noninferior to that of hyperbaric ropivacaine with intrathecal fentanyl. This suggests that addition of intrathecal fentanyl to hyperbaric ropivacaine may not be necessary in patients receiving intravenous dexmedetomidine.