alpha-2 and imidazoline receptor agonists. Their pharmacology and therapeutic role

Agmatine diminishes behavioral and endocrine alterations in a rat model of post-traumatic stress disorder

Post-traumatic stress disorder (PTSD), is a severe anxiety disorder characterized by associative fear conditioning. Single prolonged stress (SPS) is a widely accepted reliable animal model to stimulate PTSD. Agmatine is an endogenous neuromodulator of stress; however, its effect on PTSD remains to be investigated. This study explored the role of agmatine in conditioned fear response (CFR) in PTSD and highlighted the role of imidazoline receptors in the effect of agmatine. Intra-cerebroventricular (icv) surgery was done in order to facilitate drug administration. Animals were subjected to SPS. Agmatine and the involvement of imidazoline receptors (I1 and I2) were assessed for their effect in fear conditioning apparatus. During weeks 1, 2, and 3, in CFR, agmatine (40 µg/rat, icv) showed significantly decreased freezing time whereas other doses of agmatine (10 and 20 µg/rat, icv). Imidazoline (I1 and I2) receptor agonists Moxonidine (25 µg/rat, icv) and 2-BFI, (10 µg/rat, icv) respectively, at their sub-effective doses, with a submaximal dose of agmatine (20 µg/rat, icv) significantly decreased the altered freezing time during weeks 1, 2 and 3 compared to SPS animals. Moreover, the effective dose of agmatine (40 µg/rat, icv) with imidazoline (I1 and I2) receptor antagonists Efaroxan (10 µg/rat, icv) and Idazoxan (4 µg/rat, icv) respectively does not reversed the effect of agmatine on freezing. Agmatine and its combination with I1 and I2 agonists, normalized the altered freezing behavior, corticosterone level, organ coefficient of adrenal gland, neuroinflammatory and neurotrophic factor due to SPS during CFR projecting its strong therapeutic effect in SPS induced PTSD.

Dexmedetomidine suppresses glucose-stimulated insulin secretion in pancreatic β-cells

Proper glycemic control is crucial for patient management in critical care, including perioperative care, and can influence patient prognosis. Blood glucose concentration determines insulin secretion and sensitivity and affects the intricate balance between the glucose metabolism. Human and other animal studies have demonstrated that perioperative drugs, including volatile anesthetics and intravenous anesthetics, affect glucose-stimulated insulin secretion (GSIS). Dexmedetomidine (DEX) decreases insulin release and affects glucose metabolism; however, the specific mechanism underlying this phenomenon remains largely unknown. Thus, we investigated the effect and mechanism of DEX on insulin secretion using mouse and rat pancreatic β-cell-derived MIN6 and INS-1 cell lines and primary pancreatic β-cells/islets extracted from mice. The amount of insulin secreted into the culture medium was determined using an enzyme-linked immunosorbent assay. Cell viability, cytotoxicity, and electrophysiological effects were investigated. Clinically relevant doses of DEX suppressed GSIS in MIN6 cells, INS-1 cells, and pancreatic β-cells/islets. Furthermore, DEX suppressed insulin secretion facilitated by insulinotropic factors. There was no significant difference in oxygen consumption rate, intracellular ATP levels, or caspase-3/7 activity. Electrophysiological evaluation using the patch-clamp method showed that DEX did not affect ATP-sensitive potassium (KATP) channels, voltage-dependent potassium channels, or voltage-gated calcium channels. We demonstrated that clinically relevant doses of DEX significantly suppressed GSIS. These findings suggest that DEX inhibits a signaling pathway via α2-adrenoceptor or insulin vesicle exocytosis, resulting in GSIS suppression. Our results support the hypothesis that DEX suppresses insulin secretion and reveal some underlying mechanisms.

Mining and analysis of adverse events profile of Guanfacine using FDA Adverse Event Reporting System (FAERS) database

OBJECTIVE

This study aims to evaluate the Guanfacine-associated adverse events (AEs) in real-world using data mining in FAERS database, seeking to provide safety profile and guidance for the potential therapeutic practices.

METHODS

We retrospectively extracted Guanfacine-associated AEs reports in the FAERS database from the first quarter of 2004 (Q1) to the fourth quarter of 2023 (Q4). All data were strictly collected and comprehensively analyzed. Disproportionality analyses, including the reporting odds ratio (ROR), the proportional reporting ratio (PRR), the Bayesian confidence propagation neural network (BCPNN), and the empirical Bayesian geometric mean (EBGM).

RESULTS

Out of 16,985,532 reports collected from the FAERS database, 2,709 reports of Guanfacine as the 'primary suspected (PS)' and 8,464 AEs induced by Guanfacine were identified. Most AEs reports (67.45%) occurred within the first 30 days of treatment (excluding unreported or unknown onset time reports). A total of 158 significant PTs that meet all four algorithms were detected. Known neuropsychiatric events and cardiovascular events documented in the drug's leaflet were found. Besides, unexpected significant AEs such as homicidal ideation, self-injurious ideation, growth failure, excessive eye blinking were also found.

CONCLUSION

Our study has unveiled novel Guanfacine-associated AEs signals and might provide guidance for its rational use.

Optimal Dosing Recommendations of Clonidine in Pediatrics Using Physiologically Based Pharmacokinetic Modeling

OBJECTIVE

Clonidine has been widely used in the pediatric population to treat neonatal abstinence syndrome (NAS), attention deficit hyperactivity disorder (ADHD), sedation, and Tourette's syndrome; however, there is no consensus on dosing. This research aims to recommend optimal dosing of clonidine in the pediatric population using physiologically based pharmacokinetic (PBPK) modeling.

METHODS

The pediatric PBPK model was developed from an adult model by scaling the clearance processes from adults to pediatrics using ontogeny equations. The adult and pediatric models were verified using clinical PK data, and the model performance was evaluated based on visual predictive checks and absolute fold error (AFE). The final pediatric PBPK model was used to simulate clonidine PK in the virtual pediatric population. The optimal dose was recommended based on a target concentration representing clonidine's α-2 central agonist activity (EC50 = 40.5 nM).

RESULTS

The adult and pediatric models predicted well, with more than 90% of observed data captured within the 95% prediction interval of simulated data. The AFE values were within 2-fold for clonidine plasma concentrations from observed and predicted data. The pediatric simulations showed that 30 µg/kg dose orally for neonates and 0.9 mg/day orally for children (6-17 years) are optimal for achieving target concentrations for maximal α-2 adrenergic activity.

CONCLUSIONS

The pediatric PBPK model of clonidine scaled from the adult PBPK model provided optimal dosing recommendations for clonidine in different pediatric age groups. The pediatric PBPK model described in this study can be extended to other pediatric age groups and routes of administration.

Intraoperative dexmedetomidine administration and acute kidney injury in patients undergoing unilateral partial nephrectomy: a retrospective study

Partial nephrectomies are associated with an increased risk of acute kidney injury (AKI), but dexmedetomidine administration may improve renal outcomes. We hypothesized that intraoperative dexmedetomidine administration would be associated with a decrease in AKI development in patients undergoing unilateral partial nephrectomy. In this retrospective study, adult patients who underwent unilateral partial nephrectomy from April 2016 to October 2023 were included. Exclusion criteria were a history of end-stage renal disease, ineligible procedures (i.e., aborted procedure, conversion to radical nephrectomy, surgery on a horseshoe kidney), and reoperation within three days of the initial nephrectomy. Patients were categorized according to whether they received intraoperative dexmedetomidine. The primary outcome was AKI incidence within three days of surgery; AKI was defined according to the Kidney Disease Improving Global Outcomes definition. Propensity score matching (PSM) was conducted to account for potential confounders (age, body mass index, sex, American Society of Anesthesiologists score, final surgical approach, clamping-related ischemia for >15 min). We included 1,632 patients; 214 received dexmedetomidine and 1,418 did not. Before PSM, the AKI rate was 31.2% in patients who received dexmedetomidine and 25.7% in patients who did not (p = 0.081). After PSM, the AKI rate was 31.3% in patients who received dexmedetomidine and 27.6% in those who did not (p = 0.396). The post-PSM odds ratio for AKI following dexmedetomidine administration during unilateral partial nephrectomy was 0.910 (95% CI: 0.585-1.142; p = 0.677). Intraoperative dexmedetomidine was not associated with a reduction in postoperative AKI incidence or severity after unilateral partial nephrectomy.

Anaesthetics and time perception: A review

Consciousness requires subjective experience in the "now." Establishing "now," however, necessitates temporal processing. In the current article, we review one method of altering consciousness, anaesthetic drug administration, and its effects on perceived duration. We searched PubMed, PsycInfo, and ScienceDirect databases, and article reference sections, for combinations of anaesthetic drugs and time perception tasks, finding a total of 36 articles which met our inclusion criteria. We categorised these articles with regard to whether they altered the felt passage of time, short or long interval timing, or were motor timing tasks. We found that various drugs alter the perceived passage of time; ketamine makes time subjectively slow down while GABAergic drugs make time subjectively speed up. At a short interval there is little established evidence of a shift in time perception, though temporal estimates appear more variable. Similarly, when asked to use time to optimise responses (i.e., in motor timing tasks), various anaesthetic agents make timing more variable. Longer durations are estimated as lasting longer than their objective duration, though there is some variation across articles in this regard. We conclude by proposing further experiments to examine time perception under altered states of consciousness and ask whether it is possible to perceive the passage of time of events which do not necessarily reach the level of conscious perception. The variety of methods used raises the need for more systematic investigations of time perception under anaesthesia. We encourage future investigations into the overlap of consciousness and time perception to advance both fields.

Evaluation of the Surgical Pleth Index (SPI) for the monitoring of the nociception-antinociception balance in dogs undergoing castration: A prospective clinical trial

The aim of this prospective clinical study was to evaluate the efficacy of the Surgical Pleth Index (SPI), a validated nociception monitor in human anaesthesia, in dogs. The technology uses a plethysmographic signal from a specific pulse oximetry probe to analyse pulse wave amplitudes and heartbeat intervals. Twenty-six healthy dogs anaesthetised for castration were included. SPI, invasive mean arterial pressure (MAP) and heart rate (HR) were continuously monitored. The occurrence or resolution of a haemodynamic reaction (HDR), defined as a > 20% increase in HR and/or MAP, was assessed at predefined times: cutaneous incision, testicles' exteriorization, cutaneous suture, and fentanyl administration. Following nociceptive events, the dogs presenting a HDR showed a significant 8% and 10% increase in SPI at 3 and 5 min respectively, whereas after fentanyl administration, a 13% and 16% significant decrease in SPI were noted. Receiver operating characteristic curves analysis indicated a moderate performance for the dynamic variations of SPI over 1 min to predict a HDR (AUC: 0.68, threshold value: +15%) or its resolution after fentanyl administration (AUC of 0.72, threshold value: -15%) within 3 min. The SPI varied according to perioperative nociceptive events and analgesic treatment; however, its performance to anticipate a HDR was limited with high specificity but low sensivity. Refinement of the algorithm to specifically accommodate for the canine species may be warranted. Further studies are required to evaluate the influence of other factors on the performance of this index.

Novel drug treatments for pain in advanced cancer and serious illness: a focus on neuropathic pain and chemotherapy-induced peripheral neuropathy

Drugs that are commercially available but have novel mechanisms of action should be explored as analgesics. This review will discuss haloperidol, miragabalin, palmitoylethanolamide (PEA), and clonidine as adjuvant analgesics or analgesics. Haloperidol is a sigma-1 receptor antagonist. Under stress and neuropathic injury, sigma-1 receptors act as a chaperone protein, which downmodulates opioid receptor activities and opens several ion channels. Clinically, there is only low-grade evidence that haloperidol improves pain when combined with morphine, methadone, or tramadol in patients who have cancer, pain from fibrosis, radiation necrosis, or neuropathic pain. Miragabalin is a gabapentinoid approved for the treatment of neuropathic pain in Japan since 2019. In randomized trials, patients with diabetic neuropathy have responded to miragabalin. Its long binding half-life on the calcium channel subunit may provide an advantage over other gabapentinoids. PEA belongs to a group of endogenous bioactive lipids called ALIAmides (autocoid local injury antagonist amides), which have a sense role in modulating numerous biological processes in particular non-neuronal neuroinflammatory responses to neuropathic injury and systemic inflammation. Multiple randomized trials and meta-analyses have demonstrated PEA's effectiveness in reducing pain severity arising from diverse pain phenotypes. Clonidine is an alpha2 adrenoceptor agonist and an imidazoline2 receptor agonist, which is U.S. Federal Drug Administration approved for attention deficit hyperactivity disorder in children, Tourette's syndrome, adjunctive therapy for cancer-related pain, and hypertension. Clonidine activation at alpha2 adrenoceptors causes downstream activation of inhibitory G-proteins (Gi/Go), which inhibits cyclic Adenosine monophosphate (AMP) production and hyperpolarizes neuron membranes, thus reducing allodynia. Intravenous clonidine has been used in terminally ill patients with poorly controlled symptoms, in particular pain and agitation.

Clonidine for post-traumatic stress disorder: a systematic review of the current evidence

Background: Clonidine is a centrally acting anti-adrenergic agent that may have applications in post-traumatic stress disorder (PTSD), particularly for sleep.Objective: In this systematic review, we aimed to summarize the effect of clonidine on sleep quality and duration, nightmares, and PTSD symptom severity in adults with PTSD.Method: PubMed (Medline), Embase, PsycINFO, CINAHL, and clinicaltrials.gov were searched up to April 2023. Studies on clonidine use in adult PTSD patients reporting data on the effect on sleep, nightmares, and PTSD symptoms were included. A narrative summary and a meta-analysis of the study findings are presented.Results: Ten reports, accounting for N = 569 patients with PTSD (145 on clonidine and 436 controls), were included in the final selection. There were four case reports, four observational studies, one non-blind clinical trial, and one crossover randomized controlled trial (RCT). Median clonidine dose was 0.15 mg/day (range: 0.1-0.5 mg/day). Median follow-up time was 31 days (range: 3 days to 19 months). The quality of the evidence was rated from very low to low. There was marked between-study heterogeneity and low power in the individual studies, but many reported improved sleep quality, nightmare reduction, and improvement of PTSD symptoms for patients treated with clonidine. Meta-analysis was only possible for two studies reporting the effect of clonidine on nightmares, and showed no difference from the comparator (i.e. prazosin or terazosin) (odds ratio: 1.16; 95% confidence interval: 0.66 to 2.05), potentially pointing towards non-inferiority between these medications.Conclusions: Future research, such as well-powered RCTs, is needed to identify the efficacy in the lower dose range and the most suitable treatment group, and to obtain good evidence on the effects of clonidine in the treatment of sleep disorders related to PTSD.

Effects of vatinoxan in rats sedated with a combination of medetomidine, midazolam and fentanyl

BACKGROUND

Alpha2-adrenoceptor agonists (α2-agonists) are widely used in animals as sedatives and for pre-anaesthetic medication. Medetomidine has often been given subcutaneously (SC) to rats, although its absorption rate is slow and the individual variation in serum drug concentrations is high via this route. In addition, α2-agonists have various effects on metabolic and endocrine functions such as hypoinsulinaemia, hyperglycaemia and diuresis. Vatinoxan is a peripherally acting α2-adrenoceptor antagonist that, as a hydrophilic molecule, does not cross the blood-brain barrier in significant quantities and thus alleviates peripheral cardiovascular effects and adverse metabolic effects of α2-agonists. Aim of this study was to evaluate the effects of vatinoxan on sedation, blood glucose concentration, voiding and heart and respiratory rates and arterial oxygen saturation in rats sedated with subcutaneous medetomidine, midazolam and fentanyl.

RESULTS

Onset of sedation and loss of righting reflex occurred significantly faster with vatinoxan [5.35 ± 1.08 (mean ± SD) versus 12.97 ± 6.18 min and 6.53 ± 2.18 versus 14.47 ± 7.28 min, respectively]. No significant differences were detected in heart and respiratory rates and arterial oxygen saturation between treatments. Blood glucose concentration (18.3 ± 3.6 versus 11.8 ± 1.2 mmol/L) and spontaneous urinary voiding [35.9 (15.1-41.6), range (median) versus 0.9 (0-8.0) mL /kg/min] were significantly higher without vatinoxan.

CONCLUSIONS

Acceleration of induction of sedation, alleviation of hyperglycaemia and prevention of profuse diuresis by vatinoxan may be beneficial when sedating rats for clinical and experimental purposes with subcutaneous medetomidine, midazolam and fentanyl.

Safety and efficacy of dexmedetomidine in combination with local anesthetics for orthopedic nerve blocks: a systematic review and meta-analysis

INTRODUCTION

Peripheral nerve block, a common technique for managing postoperative pain and providing intraoperative analgesia, often includes adjuncts like dexmedetomidine (DEX) to enhance the effectiveness of local anesthetics. DEX, known for its α2-adrenoceptor agonist properties, extends sensory blockade and improves postoperative analgesia while offering sedative benefits. The objective of this study is to rigorously assess the effectiveness and safety of perineural DEX injection in orthopedic nerve block procedures, focusing on orthopedic surgeries to minimize heterogeneity and provide clearer insights for clinical practice.

EVIDENCE ACQUISITION

This meta-analysis, registered on PROSPERO, involved a comprehensive literature search across multiple databases, focusing on RCTs comparing DEX with local anesthetics for peripheral nerve blocks in orthopedic surgery patients. The eligibility criteria included adult participants and various nerve block methods in orthopedic surgeries. Studies were rigorously appraised for methodological quality using Cochrane Handbook guidelines. GRADE profiler 3.6 was used for evidence grading.

EVIDENCE SYNTHESIS

Among 1391 documents, 21 studies were included, focusing on DEX with local anesthetics in orthopedic nerve blocks. Findings showed significant improvements in analgesia duration, sensory and motor block duration, and reduced postoperative opioid consumption, with an increased risk of bradycardia. Quality assessments indicated moderate bias risk.

CONCLUSIONS

DEX with local anesthetics significantly enhances nerve block effectiveness, extending analgesia and block durations while reducing opioid need. However, it requires careful monitoring due to increased bradycardia risk. These findings highlight the need for cautious use in clinical practice, considering both potential benefits and adverse effects.

Comparison of the efficacy of intranasal atomised dexmedetomidine versus intranasal atomised ketamine as a premedication for sedation and anxiolysis in children undergoing spinal dysraphism surgery: A randomized controlled trial

BACKGROUND

Preoperative anxiety leads to adverse clinical outcomes and long-term maladaptive behavioural changes. The role of intranasal atomised dexmedetomidine and atomised ketamine as premedication to produce sedation and anxiolysis in paediatric neurosurgical patients has not been extensively studied.

OBJECTIVE

To study the efficacy of intranasal atomised dexmedetomidine and intranasal atomised ketamine as premedication in producing sedation and facilitating smooth induction in children undergoing spinal dysraphism surgery.

DESIGN

A prospective randomised double-blind trial.

SETTING

A tertiary teaching hospital.

PATIENTS

Sixty-four children aged 1 to 10 years undergoing spinal dysraphism surgery.

METHODS

Children were randomised to receive intranasal atomised dexmedetomidine 2.5 μg kg -1 (Group D, n  = 32) and intranasal atomised ketamine 5 mg kg -1 (Group K, n  = 32) 30 min before surgery.

OUTCOMES MEASURED

The primary outcome was to compare the level of sedation in both groups using the University of Michigan Sedation Score (UMSS). The secondary outcomes included an assessment of the ease of parental separation, intravenous cannulation and satisfactory mask acceptance along with perioperative vitals (heart rate, blood pressure and oxygen saturation). The incidence of emergence agitation and time to discharge were also noted.

RESULTS

The degree of sedation was significantly better in Group D as compared to Group K at 20 min (UMSS, 1.55 ± 0.51 versus 1.13 ± 0.34, difference, -0.406; 95% CI, -0.621 to -0.191; P  = 0.0001) and 30 min (2.32 ± 0.6 versus 1.94 ± 0.50, difference, -0.374; 95% CI, -0.650 to -0.100; P  = 0.007). The ease of parental separation, venous cannulation and mask acceptance ( P  = 0.83, 0.418 and 0.100 respectively) were comparable in both groups. The heart rate was lower in group D at 10, 20 and 30 min post-drug administration but was clinically insignificant. The incidence of emergence agitation and time to discharge was also similar with no adverse events reported.

CONCLUSION

Intranasal atomised dexmedetomidine produces greater sedation as compared to intranasal atomised ketamine with comparable ease of parental separation, venous cannulation and mask acceptance with no adverse effects.

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.

Oral Dexmedetomidine Achieves Superior Effects in Mitigating Emergence Agitation and Demonstrates Comparable Sedative Effects to Oral Midazolam for Pediatric Premedication: A Systematic Review and Meta-Analysis of Randomized Controlled Studies

Background: Oral midazolam is the most commonly used sedative premedication agent in pediatric patients. While effective, oral midazolam cannot reduce the incidence of emergence agitation. Oral dexmedetomidine may be effective in providing satisfactory sedation and reduce the incidence of emergence agitation, although the results of different randomized controlled trials are conflicting. Methods: This study enrolled randomized controlled trials (RCTs) examining premedication with oral dexmedetomidine versus oral midazolam in pediatric patients undergoing general anesthesia. PubMed, the Cochrane Library, Embase, and the Web of Science database were searched from their inception until June 2023. The outcomes were the incidence of satisfactory preoperative sedation, satisfactory sedation during separation from parents, satisfactory sedation during anesthesia induction using an anesthesia mask, and the incidence of emergence agitation. Results: A total of 9 RCTs comprising 885 patients were analyzed. Our data revealed comparable effects of dexmedetomidine and midazolam with respect to satisfactory preoperative sedation and a satisfactory incidence of sedation during parental separation and mask acceptance before anesthesia induction. Notably, our data revealed that the rate of emergence agitation was significantly lower in pediatric patients receiving dexmedetomidine (n = 162) than in those receiving midazolam (n = 159) (odds ratio = 0.16; 95% confidence interval: 0.06 to 0.44; p < 0.001; I2 = 35%). Conclusions: Data from this meta-analysis revealed comparable effects for premedication with oral dexmedetomidine or oral midazolam with respect to satisfactory sedation; furthermore, premedication with oral dexmedetomidine more effectively mitigated emergence agitation in pediatric patients receiving general anesthesia compared with oral midazolam.

Comparison of Opioid-Based Versus Opioid-Sparing Anesthesia in Patients Undergoing Glioma Surgery

Background In the neurosurgical population, opioids may cause respiratory depression, leading to hypercapnia, increased cerebral blood flow (CBF), and ultimately increased intracranial pressure (ICP), which can mask early signs of intracranial complications and delayed emergence. This study was designed to compare perioperative hemodynamic stability, analgesia, and recovery parameters in opioid-based (fentanyl) general anesthesia versus opioid-sparing (dexmedetomidine) general anesthesia in patients undergoing glioma surgeries. Methodology This prospective observational comparative study compared 52 patients in two groups. Twenty-six (50%) patients in group F received Inj. fentanyl IV (intravenous; bolus 2 mcg/kg 10 minutes before induction and then infusion 1 mcg/kg/hour till 30 minutes before skin closure), whereas 26 (50%) patients in group D received Inj. dexmedetomidine IV (0.5 mcg/kg infusion 10 minutes before induction and then maintenance with a 0.5 mcg/kg/hour infusion till 30 minutes before skin closure). Perioperative heart rate (HR), mean arterial pressure (MAP), Numerical Rating Scale for Pain (NRS) assessment and postoperative emergence time, modified Aldrete score, patient satisfaction, and surgeon satisfaction score were estimated and compared in both groups. Results The mean HR was less in group D compared to group F at following time points - 10 minutes after infusion (P = 0.006), laryngoscopy and intubation (P = 0.003), pinning of the skull (P < 0.001), one hour after dura opening (P = 0.007), two hours after dura opening (P = 0.006), five minutes after extubation (P < 0.001), and 30 minutes after extubation (P = 0.011). MAP was lower in group D compared to group F at the following time intervals: 10 minutes after infusion (P = 0.008), five minutes after extubation (P = 0.007), 30 minutes after extubation (P < 0.001), and one hour after extubation (P = 0.023). A significant decrease in emergence time in group D compared to group F (P < 0.001) was noted. NRS was lower in group D at eight hours (P = 0.005) and 12 hours (P < 0.001) post-extubation. Conclusions Dexmedetomidine can be used as an alternative to fentanyl in terms of perioperative hemodynamic stability, perioperative analgesia, smooth early recovery from anesthesia, patient satisfaction, and surgeon satisfaction.

A prospective-randomized placebo-controlled trial comparing the effects of nebulized dexmedetomidine v/s dexmedetomidine-lignocaine mixture on intraoperative hemodynamics and surgical field quality in patients undergoing endoscopic transnasal transsphenoidal pituitary tumor surgery

Background

During transnasal transsphenoidal pituitary surgery (TNTSS), the primary objective is to maintain stable hemodynamics while ensuring ideal surgical conditions. This study aimed to investigate the effect of nebulized dexmedetomidine on hemodynamic parameters and the quality of the surgical field during TNTSS.

Methods

Seventy-five patients scheduled for TNTSS were randomized into three groups of 25 each and received preoperative nebulization with 5 mL of nebulizing fluid consisting of 1.5 μg/kg of dexmedetomidine with saline in dexmedetomidine (D) group; 1.5 μg/kg of dexmedetomidine with 2% lignocaine in dexmedetomidine-lignocaine (DL) group and normal saline in the control (S) group. Heart rate (HR), mean blood pressure, Formmers score, anesthetic requirement, and emergence were evaluated for each group.

Results

Group S had significantly higher HR and mean arterial pressure than the other two groups across various time points during surgery (P < 0.01). The total requirements for fentanyl, propofol, sevoflurane, and labetalol and the incidence of delayed emergence were significantly higher in the S group compared to the other two groups (P < 0.01). The D and DL groups exhibited significantly better surgical field conditions than the S group. In all the parameters assessed, patients in the D group outperformed those in the DL group.

Conclusion

The administration of nebulized dexmedetomidine, both alone and in combination with lignocaine, resulted in stable hemodynamics, favorable operative conditions, reduced anesthetic requirement, and facilitated prompt emergence during TNTSS. Nebulized dexmedetomidine proved superior to its combination with lignocaine across all evaluated parameters.

Adrenergic mechanisms of absence status epilepticus

Absence status epilepticus is a prolonged, generalized absence seizure that lasts more than half an hour. The mechanisms underlying the absence of status epilepticus are still not entirely understood. In this study, the study concentrates on alpha2-adrenergic mechanisms of absence status using the WAG/Rij rat model. In this model, a prolonged spike-wave activity was associated with a specific behavioral state in transition between sedation («alpha2-wakefulness»)-resembled absence status in human patients. Pharmacological activation of alpha2-adrenoreceptors may target the locus coeruleus (presynaptic alpha2-adrenoreceptors) and the thalamic part of the seizure-generating thalamocortical system (postsynaptic alpha2B-adrenoreceptors). The duration of EEG-behavioral correlates of absence status was not dose-dependent and was predetermined by the intensity of absence seizures at baseline. This model could help scientists better understand the underlying causes of absence status and develop more effective and personalized treatments for each individual.

Dexmedetomidine as an anesthetic adjunct is associated with reduced complications and cardiac intensive care unit length of stay after heart valve surgery

BACKGROUND

We sought to explore the relationship between dexmedetomidine as an anesthetic adjuvant in cardiac surgery and postoperative complications and length of stay (LOS) in the cardiac intensive care unit (CICU).

METHODS

We conducted a retrospective study of patients aged 18 years and older who underwent heart valve surgery between October 2020 and June 2022. The primary endpoint of the study was major postoperative complications (cardiac arrest, atrial fibrillation, myocardial injury/infarction, heart failure) and the secondary endpoint was prolonged CICU LOS (defined as LOS > 90th percentile). Multivariate logistic regression analysis was performed for variables that were significant in the univariate analysis.

RESULTS

A total of 856 patients entered our study. The 283 patients who experienced the primary and secondary endpoints were included in the adverse outcomes group, and the remaining 573 were included in the prognostic control group. Multivariate logistic regression analysis revealed that age > 60 years (odds ratio [OR], 1.68; 95% confidence interval [CI], 1.23-2.31; p < 0.01), cardiopulmonary bypass (CPB) > 180 min (OR, 1.62; 95% CI, 1.03-2.55; p = 0.04) and postoperative mechanical ventilation time > 10 h (OR, 1.84; 95% CI, 1.35-2.52; p < 0.01) were independent risk factors for major postoperative complications; Age > 60 years (OR, 3.20; 95% CI, 1.65-6.20; p < 0.01), preoperative NYHA class 4 (OR, 4.03; 95% CI, 1.74-9.33; p < 0.01), diabetes mellitus (OR, 2.57; 95% CI, 1.22-5.41; p = 0.01), Intraoperative red blood cell (RBC) transfusion > 650 ml (OR, 2.04; 95% CI, 1.13-3.66; p = 0.02), Intraoperative bleeding > 1200 ml (OR, 2.69; 95% CI, 1.42-5.12; p < 0.01) were independent risk factors for prolonged CICU length of stay. Intraoperative use of dexmedetomidine as an anesthetic adjunct was a protective factor for major complications (odds ratio, 0.51; 95% confidence interval, 0.35-0.74; p < 0.01) and prolonged CICU stay. (odds ratio, 0.37; 95% confidence interval, 0.19-0.73; p < 0.01).

CONCLUSIONS

In patients undergoing heart valve surgery, age, duration of cardiopulmonary bypass, and duration of mechanical ventilation are associated with major postoperative complication. Age, preoperative NYHA classification 4, diabetes mellitus, intraoperative bleeding, and RBC transfusion are associated with increased CICU length of stay. Intraoperative use of dexmedetomidine may improve such clinical outcomes.

A Comparative Study of Morphine and Clonidine as an Adjunct to Ropivacaine in Paravertebral Block for Modified Radical Mastectomy

Background General anesthesia (GA) is a standard for breast malignant surgery. The issue of postoperative pain as well as the high occurrence of nausea and vomiting have prompted the quest for a superior methodology for tormenting the executives with fewer complications. Over the most recent couple of years, paravertebral block (PVB) has acquired huge fame either in combination with GA or alone for anesthetic management. In this study, we aim to evaluate the efficacy of morphine and clonidine as an adjunct to ropivacaine in PVB in breast cancer patients undergoing modified radical mastectomy. Methods In this study, a total of 90 patients were divided into the following three groups (30 each) based on a computer-generated random table. Group C (control): PVB with 0.25% ropivacaine (19 ml) 1 ml saline; Group M: PVB with 0.25% ropivacaine (19 ml) + 20 microgram/kg body weight morphine; Group N: PVB with 0.25% ropivacaine (19 ml) + 1.0 microgram/kg body weight clonidine. The postoperative pain intensity was recorded using the visual analog scale (VAS), and sedation was observed by the Ramsay Sedation Scale (RSS) score. Results The VAS was similar at zero hours, two hours, and four hours in the postoperative period among all the groups. There was a significant (p = 0.003) difference in VAS from six hours to 20 hours in the postoperative period among the groups. A significant (p < 0.05) difference was observed among the groups at eight hours to 20 hours. The first requirement of analgesia was significantly (p = 0.001) higher in Group N (7.70 ± 1.74) than in Group C (4.43 ± 1.43) and Group M (7.33 ± 2.21). Conclusion Morphine in the PVB provides better postoperative analgesia. The consumption of rescue analgesia was significantly reduced in the morphine group as compared to the clonidine group. The procedure also proved to be safe as no complication was encountered in the PVB in our study.

Evaluation of the Averaged Parasympathetic Tone Activity and Its Dynamic Variation to Assess Intraoperative Nociception in Relation to Hemodynamic Changes in Dogs

This study aimed to determine the performance of the averaged parasympathetic tone activity (PTAm) and its dynamic variation (ΔPTA) to assess intraoperative nociception in relation to heart rate (HR) and direct mean arterial pressure (MAP) in dogs undergoing laparoscopic ovariectomy. This prospective, observational, clinical study included 32 bitches. The PTAm, HR, MAP, and bispectral index (BIS) were assessed before (pre-stimulus), as well as 1 min and 2 min after, four surgical stimuli: insufflation, introduction of trocars, and removal of the left and right ovaries. A two-way ANOVA was performed to compare PTAm, HR, MAP, and BIS data across surgical stimuli. A ≥20% drop in PTAm or a ≥20% increase in HR and/or MAP regarding the pre-stimulus values was considered a PTAm-drop and/or a hemodynamic response, respectively. The performance of PTAm pre-stimulus, PTAm 1 min, and ΔPTA in predicting the hemodynamic response was assessed by calculation of the area under the receiver operating characteristic (ROC) curve. At insufflation, PTAm decreased after 1 (p = 0.010) and 2 (p = 0.045)min, and ΔPTA was different (p = 0.005) between dogs that presented hemodynamic response and dogs that did not. At PTAm-drop, MAP increased after 1 min (p = 0.001) and 2 min (p = 0.001) with respect to pre-stimulus value, whereas HR and BIS did not change. ROC curves showed a threshold value of PTAm pre-stimulus ≤51 to detect hemodynamic response (sensitivity 69%, specificity 52%). The PTAm and ΔPTA only assessed intraoperative nociception during insufflation. The PTAm pre-stimulus association to the hemodynamic response in anaesthetized dogs showed poor sensitivity and no specificity.

Using pharmacotherapy to address sleep disturbances in autism spectrum disorders

INTRODUCTION

Sleep disorders are the second most common medical comorbidity in autism spectrum disorder (ASD), with effects on daytime behavior and functioning, mood and anxiety, and autism core features. In children with ASD, insomnia also has a negative impact on the whole family's quality of life. Therefore, treatment of sleep disturbances should be considered as a primary goal in the management of ASD patients, and it is important to clarify the scientific evidence to inappropriate treatments.

AREAS COVERED

The authors review the current literature concerning the pharmacological treatment options for the management of sleep-related disorders in patients with ASD (aged 0-18 years) using the PubMed and Cochrane Library databases with the search terms: autism, autistic, autism spectrum disorder, ASD, drug, drug therapy, drug intervention, drug treatment, pharmacotherapy, pharmacological treatment, pharmacological therapy, pharmacological intervention, sleep, sleep disturbance, and sleep disorder.

EXPERT OPINION

Currently, clinicians tend to select medications for the treatment of sleep disorders in ASD based on the first-hand experience of psychiatrists and pediatricians as well as expert opinion. Nevertheless, at the present time, the only compound for which there is sufficient evidence is melatonin, although antihistamines, trazodone, clonidine, ramelteon, gabapentin, or suvorexant can also be considered for selection.

Comparison of dexmedetomidine with midazolam for third molar surgery: A meta-analysis of randomized controlled trials

INTRODUCTION

The analgesic sedation of dexmedetomidine compared with midazolam for third molar surgery remains controversial. We conduct a systematic review and meta-analysis to explore the influence of dexmedetomidine versus midazolam for third molar surgery.

METHODS

We have searched PubMed, EMbase, Web of science, EBSCO, and Cochrane library databases through December 2022 for randomized controlled trials assessing the effect of dexmedetomidine versus midazolam for third molar surgery. This meta-analysis was performed using the random-effect model.

RESULTS

Four randomized controlled trials were included in the meta-analysis. Overall, compared with midazolam for third molar surgery, dexmedetomidine administration leads to comparable oxygen saturation (standard mean difference [SMD] = 0.25; 95% confidence interval [CI] = -0.24 to 0.74; P = .31), heart rate (SMD = -0.37; 95% CI = -1.18 to 0.44; P = .37), SBP (SMD = -0.24; 95% CI = -0.57 to 0.09; P = .16), DBP (SMD = -0.26; 95% CI = -0.60 to 0.07; P = .12), as well as nausea and vomiting (OR = 0.58; 95% CI = 0.05-6.61; P = .66).

CONCLUSIONS

Dexmedetomidine may obtain the comparable sedation efficacy with midazolam for third molar surgery.

Pharmacological interventions for preventing opioid-induced hyperalgesia in adults after opioid-based anesthesia: a systematic review and network meta-analysis

Background: Opioid-induced hyperalgesia (OIH) is an adverse event of prolonged opioid use that increases pain intensity. The optimal drug to prevent these adverse effects is still unknown. We aimed to conduct a network meta-analysis to compare different pharmacological interventions for preventing the increase in postoperative pain intensity caused by OIH. Methods: Several databases were searched independently for randomized controlled trials (RCTs) comparing various pharmacological interventions to prevent OIH. The primary outcomes were postoperative pain intensity at rest after 24 h and the incidence of postoperative nausea and vomiting (PONV). Secondary outcomes included pain threshold at 24 h after surgery, total morphine consumption over 24 h, time to first postoperative analgesic requirement, and shivering incidence. Results: In total, 33 RCTs with 1711 patients were identified. In terms of postoperative pain intensity, amantadine, magnesium sulphate, pregabalin, dexmedetomidine, ibuprofen, flurbiprofen plus dexmedetomidine, parecoxib, parecoxib plus dexmedetomidine, and S (+)-ketamine plus methadone were all associated with milder pain intensity than placebo, with amantadine being the most effective (SUCRA values = 96.2). Regarding PONV incidence, intervention with dexmedetomidine or flurbiprofen plus dexmedetomidine resulted in a lower incidence than placebo, with dexmedetomidine showing the best result (SUCRA values = 90.3). Conclusion: Amantadine was identified as the best in controlling postoperative pain intensity and non-inferior to placebo in the incidence of PONV. Dexmedetomidine was the only intervention that outperformed placebo in all indicators. Clinical Trial Registration: https://www.crd.york.ac. uk/prospero/display_record.php?, CRD42021225361.

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.

Comparison of the perfusion index as an index of noxious stimulation in monitored anesthesia care of propofol/remifentanil and propofol/dexmedetomidine: a prospective, randomized, case-control, observational study

BACKGROUND

Dexmedetomidine, one of the sedatives, has an analgesic effect. We aimed to investigate postoperative analgesia with dexmedetomidine as adjuvants for procedural sedation using perfusion index (PI).

METHODS

In this prospective, randomized, case-control, observational study, 72 adult patients, 19-70 years, who were scheduled for chemoport insertion under monitored anesthesia care were performed. According to the group assignment, remifentanil or dexmedetomidine was simultaneously infused with propofol. The primary outcome was PI 30 min after admission to the post anesthesia care unit (PACU). And, pain severity using numerical rating scale (NRS) score and the relationship between NRS score and PI were investigated.

RESULTS

During PACU staying, PI values were significantly different between the two groups PI values at 30 min after admission to the PACU were 1.3 (0.9-2.0) in the remifentanil group and 4.5 (2.9-6.8) in the dexmedetomidine group (median difference, 3; 95% CI, 2.1 to 4.2; P < 0.001). The NRS scores at 30 min after admission to the PACU were significantly lower in the dexmedetomidine group (P = 0.002). However, there was a weak positive correlation between NRS score and PI in the PACU (correlation coefficient, 0.188; P = 0.01).

CONCLUSION

We could not find a significant correlation between PI and NRS score for postoperative pain control. Using PI as a single indicator of pain is insufficient.

TRIAL REGISTRATION

Clinical Trial Registry of Korea, https://cris.nih.go.kr : KCT0003501, the date of registration: 13/02/2019.

Sleep disturbances in autism spectrum disorder: Animal models, neural mechanisms, and therapeutics

Sleep is crucial for brain development. Sleep disturbances are prevalent in children with autism spectrum disorder (ASD). Strikingly, these sleep problems are positively correlated with the severity of ASD core symptoms such as deficits in social skills and stereotypic behavior, indicating that sleep problems and the behavioral characteristics of ASD may be related. In this review, we will discuss sleep disturbances in children with ASD and highlight mouse models to study sleep disturbances and behavioral phenotypes in ASD. In addition, we will review neuromodulators controlling sleep and wakefulness and how these neuromodulatory systems are disrupted in animal models and patients with ASD. Lastly, we will address how the therapeutic interventions for patients with ASD improve various aspects of sleep. Together, gaining mechanistic insights into the neural mechanisms underlying sleep disturbances in children with ASD will help us to develop better therapeutic interventions.

Considerations for Satisfactory Sedation during Dental Implant Surgery

Implant surgery is a lengthy dental procedure, and sedation is often used to reduce discomfort. The effectiveness of sedation has traditionally been evaluated in terms of patient and surgeon satisfaction, but the most important goal is not to induce a deep sleep in the patient, but rather to ensure that the surgery is performed safely and as planned. Additionally, adequate pain control is a necessary requirement for patient and surgeon satisfaction. Most patients undergoing implant surgery are middle-aged or older, and a relatively large number of them have cardiovascular disease. Infiltration anesthesia using articaine or lidocaine in combination with adrenaline is widely used, but its use in patients with cardiovascular disease is limited because of adrenaline's effects on the cardiovascular system. The use of long-acting local anesthetics and the potential efficacy of ultrasound-guided jaw nerve block have been investigated to enhance analgesia without resorting to adrenaline. Midazolam and propofol are usually used for sedation, but dexmedetomidine, which causes less respiratory depression, and the ultrashort-acting benzodiazepine remimazolam are emerging as potential alternatives. Monitoring of anesthetic depth using electroencephalography is effective in maintaining a constant level of sedation. In addition, sedation promotes the stabilization of heart rate and blood pressure, reducing the risks associated with adrenaline and allowing for safer management.

Comparison of single-shot nebuliser protocol between dexmedetomidine and ketamine in children undergoing magnetic resonance imaging

BACKGROUND

Sedation for magnetic resonance imaging mandates deep sedation to ensure patient immobility. The nebulised route of drug delivery carries the advantage of good bioavailability and safety profile. We aimed to compare the efficacy and safety of nebulised dexmedetomidine and ketamine for sedation in children undergoing magnetic resonance imaging.

METHODS

A total of 71 children, aged two to eight years scheduled for outpatient magnetic resonance imaging were randomly allocated to receive nebulised dexmedetomidine 2 μg/kg (group D) or nebulised ketamine 2 mg/kg (group K) 30min before magnetic resonance imaging.

RESULTS

Nebulised dexmedetomidine (2 μg/kg) resulted in faster onset and significantly better sedation scores with rapid clear-headed recovery. Ketamine resulted in better venepuncture scores but was associated with more neuropsychological events at recovery.

CONCLUSION

Nebulised dexmedetomidine at 2 μg/kg provides rapid onset of satisfactory sedation, with good parental separation and a quicker and more clear-headed recovery, allowing for a smooth magnetic resonance imaging experience.

Effects of perioperative dexmedetomidine infusion on renal function and microcirculation in kidney transplant recipients: a randomised controlled trial

OBJECTIVE

Ischemia-reperfusion injury affects postoperative transplanted kidney function in kidney transplant recipients. Dexmedetomidine was reported to attenuate ischemia-reperfusion injury and improve microcirculation, but its propensity to cause bradycardia and hypotension may adversely affect microcirculation. This study investigated the effect of dexmedetomidine on postoperative renal function and sublingual microcirculation in kidney recipients.

METHODS

The enrolled kidney transplant recipients were randomly allocated to the control group or dexmedetomidine group. After anaesthesia induction, patients in the dexmedetomidine group received dexmedetomidine infusion until 2 h after surgery. Sublingual microcirculation was recorded using an incident dark-field video microscope and analysed. The primary outcomes were the creatinine level on a postoperative day 2 and total vessel density at 2 h after surgery.

RESULTS

A total of 60 kidney recipients were analysed, and the creatinine levels on postoperative day 2 were significantly lower in the dexmedetomidine group than in the control group (1.5 (1.1-2.4) vs. 2.2 (1.7-3.0) mg/dL, median difference -0.6 (95% CI, -0.7 to -0.5) mg/dL, p = .018). On a postoperative day 7, the creatinine levels did not differ significantly between the two groups. Total vessel density at 2 h after surgery did not differ significantly between the two groups.

CONCLUSION

We found that early postoperative renal function was better in kidney transplant recipients receiving dexmedetomidine infusion, but total vessel density was not significantly different between the intervention and control groups. Key messagesIschemia-reperfusion injury affects postoperative transplanted kidney function, and dexmedetomidine was reported to attenuate ischemia-reperfusion injury and improve microcirculation in other clinical conditions.This study showed that early postoperative renal function was better in kidney transplant recipients receiving dexmedetomidine.Dexmedetomidine's side effect of bradycardia and hypotension may affect microcirculation, our results revealed that the perioperative sublingual microcirculation did not differ significantly in kidney transplant recipients receiving dexmedetomidine.

The differential in vivo contribution of spinal α2A- and α2C-adrenoceptors in tonic and acute evoked nociception in the rat

Spinal α₂-adrenoceptor induces analgesia by neuronal inhibition of primary afferent fibers. This family receptor coupled to G _i/o proteins can be subdivided into three functional subtypes: α_2A, α_2B, and α_2C-adrenoceptors, and current evidence on spinal analgesia supports the relevance of α_2A and seems to exclude the role of α_2B, but the functional contribution of α_2C-adrenoceptors remains elusive. The present study was designed to pharmacologically dissect the contribution of spinal α₂-adrenoceptor subtypes modulating tonic or acute peripheral nociception. Using male Wistar rats, we analyzed the effect of spinal clonidine (a non-selective α_2A/α_2B/α_2C-adrenoceptor agonist) and/or selective subtype α₂-adrenoceptor antagonists on: 1) tonic nociception induced by subcutaneous formalin (flinching behavior) or 2) acute nociception induced by peripheral electrical stimulus in in vivo extracellular recordings of spinal dorsal horn second-order wide dynamic range (WDR) neurons. Clonidine inhibited the nocifensive behavior induced by formalin, an effect blocked by BRL 44408 (α_2A-adrenoceptor antagonist) but not by imiloxan (α_2B-adrenoceptor antagonist) or JP 1302 (α_2C-adrenoceptor antagonist). Similarly, spinal BRL 44408 reversed the clonidine-induced inhibition of nociceptive WDR activity. Interestingly, spinal JP 1302 per se produced behavioral antinociception (an effect blocked by bicuculline, a preferent GABA_A channel blocker), but no correlation was found with the electrophysiological experiments. These data imply that, at the spinal level, 1) presynaptic α_2A-adrenoceptor activation produces antinociception during acute or tonic nociceptive stimuli; and 2) under tonic nociceptive (inflammatory) input, spinal α_2C-adrenoceptors are pronociceptive, probably by the inactivation of GABAergic transmission. This result supports a differential role of α_2A and α_2C-adrenoceptors modulating nociception.

Postoperative analgesic effect of dexmedetomidine combined with TPVB applied to open gastrectomy for gastric cancer

OBJECTIVES

This study is aimed to investigate the analgesic effect of combined dexmedetomidine and thoracic paravertebral nerve block (TPVB) on gastric cancer (GC) patients undergoing open gastrectomy.

METHODS

From May 2019 to Nov 2020, a total of 80 GC patients preparing for open gastrectomy were enrolled in our hospital and were divided into the ropivacaine (RO) group and the ropivacaine + dexmedetomidine (RD) group ad libitum. All of the patients underwent TPVB. The characteristics, usage of patient-controlled analgesia (PCA), adverse events, visual analogue scale (VAS) scores, inflammatory cytokines, and T cell subgroups between the two groups were compared.

RESULTS

Patients in the RD group showed the decreased occurrence rate of postoperative adverse events and VAS scores and improved anti-inflammation and immune function. These findings implied that the application of dexmedetomidine in combination with ropivacaine in TPVB has a good postoperative analgesic effect, as well as anti-inflammatory and immune-enhancing effects.

CONCLUSION

Dexmedetomidine as an adjunct analgesic may be potentially applied in clinical practice for GC patients undergoing open gastrectomy.

Dexmedetomidine attenuates lipopolysaccharide-induced inflammation through macrophageal IL-10 expression following α7 nAchR activation

Dexmedetomidine, a highly selective α₂-adrenoceptor agonist, has been recently reported to alleviate systemic inflammatory response induced by lipopolysaccharide (LPS), in addition to its sedative, analgesic, bradycardic and hypotensive properties. This study aimed to illustrate the molecular mechanisms underlying dexmedetomidine-induced anti-inflammation. In the LPS-pretreated mice, subcutaneous injection of dexmedetomidine reduced the spleen weight as well as serum and spleen expression of proinflammatory cytokines, tumor necrosis factor-α (TNF-α), interleukin (IL)-6 and IL-1β, and increased serum and spleen expression of IL-10, a known anti-inflammatory cytokine. In addition, dexmedetomidine-attenuated proinflammatory cytokine reduction was entirely inhibited by selective α7 nicotinic acetylcholine receptor (nAChR) antagonist methyllycaconitine but not α₂-adrenoceptor antagonist yohimbine. Dexmedetomidine also increased macrophageal IL-10 expression in the presence and absence of LPS, which was also attenuated by methyllycaconitine but not yohimbine. Furthermore, the stimulatory effect of dexmedetomidine on the expression of IL-10 was also reduced by the α7 nAChR gene silencer siRNA/α7 nAChR. Lastly, pretreatment with the IL-10 neutralizing antibody reversed dexmedetomidine-supressed expression of proinflammatory cytokines. Our findings illustrate that dexmedetomidine-induced anti-inflammation is through macrophageal expression of IL-10 following activation of α7 nAchRs but not α₂-adrenoceptors.

Comparative Study of Intranasal Dexmedetomidine Versus Intranasal Ketamine as Premedicant in Children

Background: Pre-operative anxiety in children not only makes induction difficult but it is also associated with an increase in the requirement of analgesics, the incidence of post-operative nausea and vomiting (PONV), emergence delirium (ED), and postoperative maladaptive behavioral changes. It can be reduced effectively by pharmacological interventions. In a quest to find the ideal premedicant and non-invasive way of its administration, we decided to compare intranasal (IN) dexmedetomidine with IN ketamine as a premedicant in pediatric patients.

Aims and objectives: To compare sedation score, mask acceptance score (MAS) during induction, the incidence of ED, and other adverse events in both groups.

Material and methods: Some 60 children, between 1 and 8 years of age of either sex undergoing surgical procedures were included in this study and randomly divided into two groups (Group D and Group K). Thirty minutes prior to induction of anesthesia, patients of Group D received dexmedetomidine 1 mcg kg^-1 in 1 mL of 0.9% saline intranasally and patients of Group K received ketamine 5 mg kg^-1 in 1 mL of 0.9% saline intranasally through calibrated dropper (0.5 mL in each nostril) in a recumbent position. Incidences of sneezing or coughing after IN administration of study drugs were recorded. The subsequent sedation scores were assessed using MOASS at 15 min, then at 30 min following premedication at the time of parental separation. After shifting patients to operation theater inhalation induction was done. MAS at induction and any adverse effects were recorded.

Results: Children in Group K were found to be significantly more sedated at 30 min after administration of premedication and mask acceptance was also better (p value < 0.0001 with a confidence interval, CI=95%). But the incidence of ED and PONV was high.

Conclusion: Intranasal dexmedetomidine (1 mcg kg^-1) is clinically less effective as a premedicant in terms of sedation and mask acceptance in older children as compared to ketamine (5 mg kg^-1), but associated with fewer incidence of ED and PONV. We recommend the usage of IN dexmedetomidine in a higher dose (1.5-2 mcg kg^-1), through nebulization/atomizer for the desired level of sedation and mask acceptance.

Alpha-2-adrenergic receptor agonists for the prevention of delirium and cognitive decline after open heart surgery (ALPHA2PREVENT): protocol for a multicentre randomised controlled trial

INTRODUCTION

Postoperative delirium is common in older cardiac surgery patients and associated with negative short-term and long-term outcomes. The alpha-2-adrenergic receptor agonist dexmedetomidine shows promise as prophylaxis and treatment for delirium in intensive care units (ICU) and postoperative settings. Clonidine has similar pharmacological properties and can be administered both parenterally and orally. We aim to study whether repurposing of clonidine can represent a novel treatment option for delirium, and the possible effects of dexmedetomidine and clonidine on long-term cognitive trajectories, motor activity patterns and biomarkers of neuronal injury, and whether these effects are associated with frailty status.

METHODS AND ANALYSIS

This five-centre, double-blind randomised controlled trial will include 900 cardiac surgery patients aged 70+ years. Participants will be randomised 1:1:1 to dexmedetomidine or clonidine or placebo. The study drug will be given as a continuous intravenous infusion from the start of cardiopulmonary bypass, at a rate of 0.4 µg/kg/hour. The infusion rate will be decreased to 0.2 µg/kg/hour postoperatively and be continued until discharge from the ICU or 24 hours postoperatively, whichever happens first.Primary end point is the 7-day cumulative incidence of postoperative delirium (Diagnostic and Statistical Manual of Mental Disorders, fifth edition). Secondary end points include the composite end point of coma, delirium or death, in addition to delirium severity and motor activity patterns, levels of circulating biomarkers of neuronal injury, cognitive function and frailty status 1 and 6 months after surgery.

ETHICS AND DISSEMINATION

This trial is approved by the Regional Committee for Ethics in Medical Research in Norway (South-East Norway) and by the Norwegian Medicines Agency. Dissemination plans include publication in peer-reviewed medical journals and presentation at scientific meetings.

TRIAL REGISTRATION NUMBER

NCT05029050.

Comparison of adjuvant pharmaceuticals for caudal block in pediatric lower abdominal and urological surgeries: A network meta-analysis

STUDY OBJECTIVE

Caudal block helps relieve pain after sub-umbilical surgery in pediatric patients; however, the duration for which it exerts its analgesic effect is limited. The addition of certain adjuvant agents to local anesthetics (LAs) that are used to administer caudal block can prolong postoperative analgesia. Therefore, we aimed to compare the efficiencies and side effects of caudal adjuvants in the settings of pediatric lower abdominal and urological surgeries.

DESIGN

A network meta-analysis (NMA).

PATIENTS

One hundred and twelve randomized controlled trials (RCTs) involving 6800 pediatric patients were included in the final analysis.

INTERVENTIONS

Different adjuvant agents, namely clonidine, dexamethasone, dexmedetomidine, fentanyl, ketamine, magnesium, midazolam, morphine, neostigmine, and tramadol.

MEASUREMENTS

The primary outcome was the duration of analgesia. The secondary outcomes included the requirement for additional analgesia, analgesic consumption, and postoperative complications. The effects and rankings were evaluated using NMA and the surface under the cumulative ranking curve scores, respectively.

RESULTS

Neostigmine, dexmedetomidine, and dexamethasone were found to be the three most effective adjuvants that prolong the duration of analgesia for caudal block, and these adjuvants extended this duration by 8.9 h (95% confidence interval [CI], 7.1-10.7), 7.3 h (95% CI, 6.0-8.6), and 5.9 h (95% CI, 4.0-7.7), respectively. Caudal neostigmine was associated with an increase in the incidence of postoperative nausea and vomiting, whereas dexmedetomidine and dexamethasone showed no postoperative complications.

CONCLUSIONS

This NMA provided evidence and suggested that dexmedetomidine and dexamethasone may be the most beneficial adjuvant pharmaceutics adding to LAs for caudal block in children. However, given the off-label status of caudal dexmedetomidine and dexamethasone, further high-quality RCTs are still warranted, especially to determine whether delayed neurological complications will occur.

Topical clonidine for neuropathic pain in adults

BACKGROUND

Clonidine is a presynaptic alpha-2-adrenergic receptor agonist that has been used for many years to treat hypertension and other conditions, including chronic pain. Adverse events associated with systemic use of the drug have limited its application. Topical use of drugs has been gaining interest since the beginning of the century, as it may limit adverse events without loss of analgesic efficacy. Topical clonidine (TC) formulations have been investigated for almost 20 years in clinical trials. This is an update of the original Cochrane Review published in Issue 8, 2015.

OBJECTIVES

The objective of this review was to assess the analgesic efficacy and safety of TC compared with placebo or other drugs in adults aged 18 years or above with chronic neuropathic pain.

SEARCH METHODS

For this update we searched the Cochrane Register of Studies Online (CRSO), MEDLINE (Ovid), and Embase (Ovid) databases, and reference lists of retrieved papers and trial registries. We also contacted experts in the field. The most recent search was performed on 27 October 2021.

SELECTION CRITERIA

We included randomised, double-blind studies of at least two weeks' duration comparing TC versus placebo or other active treatment in adults with chronic neuropathic pain.

DATA COLLECTION AND ANALYSIS

Two review authors independently screened references for eligibility, extracted data, and assessed risk of bias. Any discrepancies were resolved by discussion or by consulting a third review author if necessary. Where required, we contacted trial authors to request additional information. We presented pooled estimates for dichotomous outcomes as risk ratios (RRs) with 95% confidence intervals (CIs), and continuous outcomes as mean differences (MDs) with P values. We used Review Manager Web software to perform the meta-analyses. We used a fixed-effect model if we considered heterogeneity as not important; otherwise, we used a random-effects model.  The review primary outcomes were: participant-reported pain relief of 50% or greater; participant-reported pain relief of 30% or greater; much or very much improved on Patient Global Impression of Change scale (PGIC); and very much improved on PGIC. Secondary outcomes included withdrawals due to adverse events; participants experiencing at least one adverse event; and withdrawals due to lack of efficacy. All outcomes were measured at the longest follow-up period. We assessed the certainty of evidence using GRADE and created two summary of findings tables.

MAIN RESULTS

We included four studies in the review (two new in this update), with a total of 743 participants with painful diabetic neuropathy (PDN). TC (0.1% or 0.2%) was applied in gel form to the painful area two to three times daily. The double-blind treatment phase of three studies lasted 8 weeks to 85 days and compared TC versus placebo. In the fourth study, the double-blind treatment phase lasted 12 weeks and compared TC versus topical capsaicin. We assessed the studies as at unclear or high risk of bias for most domains; all studies were at unclear risk of bias for allocation concealment and blinding of outcome assessment; one study was at high risk of bias for blinding of participants and personnel; two studies were at high risk of attrition bias; and three studies were at high risk of bias due to notable funding concerns. We judged the certainty of evidence (GRADE) to be moderate to very low, downgrading for study limitations, imprecision of results, and publication bias. TC compared to placebo There was no evidence of a difference in number of participants with participant-reported pain relief of 50% or greater during longest follow-up period (12 weeks) between groups (risk ratio (RR) 1.21, 95% confidence interval (CI) 0.78 to 1.86; 179 participants; 1 study; low certainty evidence). However, the number of participants with participant-reported pain relief of 30% or greater during longest follow-up period (8 to 12 weeks) was higher in the TC group compared with placebo (RR 1.35, 95% CI 1.03 to 1.77; 344 participants; 2 studies, very low certainty evidence). The number needed to treat for an additional beneficial outcome (NNTB) for this comparison was 8.33 (95% CI 4.3 to 50.0). Also, there was no evidence of a difference between groups for the outcomes much or very much improved on the PGIC during longest follow-up period (12 weeks) or very much improved on PGIC during the longest follow-up period (12 weeks) (RR 1.06, 95% CI 0.76 to 1.49 and RR 1.82, 95% CI 0.89 to 3.72, respectively; 179 participants; 1 study; low certainty evidence). We observed no evidence of a difference between groups in withdrawals due to adverse events and withdrawals due to lack of efficacy during the longest follow-up period (12 weeks) (RR 0.34, 95% CI 0.04 to 3.18 and RR 1.01, 95% CI 0.06 to 15.92, respectively; 179 participants; 1 study; low certainty evidence) and participants experiencing at least one adverse event during longest follow-up period (12 weeks) (RR 0.65, 95% CI 0.14 to 3.05; 344 participants; 2 studies; low certainty evidence).  TC compared to active comparator There was no evidence of a difference in the number of participants with participant-reported pain relief of 50% or greater during longest follow-up period (12 weeks) between groups (RR 1.41, 95% CI 0.99 to 2.0; 139 participants; 1 study; low certainty evidence). Other outcomes were not reported.

AUTHORS' CONCLUSIONS

This is an update of a review published in 2015, for which our conclusions remain unchanged. Topical clonidine may provide some benefit to adults with painful diabetic neuropathy; however, the evidence is very uncertain. Additional trials are needed to assess TC in other neuropathic pain conditions and to determine whether it is possible to predict who or which groups of people will benefit from TC.

Electroencephalogram Mechanism of Dexmedetomidine Deepening Sevoflurane Anesthesia

Dexmedetomidine, as an α2-adrenoceptor agonist, plays anti-sympathetic, sedative and analgesic roles in perioperative period. Also, dexmedetomidine can reduce the minimal alveolar concentration (MAC) of sevoflurane and the risk of postoperative cognitive dysfunction (POCD) induced by sevoflurane anesthesia. But so far, the electroencephalogram (EEG) mechanism of dexmedetomidine deepening sevoflurane anesthesia is not clear. In this study, by analyzing the changes of the power spectrum and bicoherence spectrum of EEG before and after dexmedetomidine infusion, the EEG mechanism of dexmedetomidine deepening sevoflurane anesthesia was studied. We analyzed dexmedetomidine-induced changes in power spectrum and bicoherence spectrum in 23 patients under sevoflurane anesthesia. After anesthesia induction, the sevoflurane concentration was maintained at 0.8 MAC for 15 min, and then dexmedetomidine was administered at a loading dose of 0.8 μg/kg in 10 min, followed by a maintenance rate of 0.5 μg⋅kg^–1⋅h^–1. Frontal EEG data from 5 min before and 10 min after dexmedetomidine infusion were compared. After dexmedetomidine infusion, the mean α power peak decreased from 6.09 to 5.43 dB and shifted to a lower frequency, the mean θ bicoherence peak increased from 29.57 to 41.25% and shifted to a lower frequency, and the median α bicoherence peak increased from 41.49 to 46.36% and shifted to a lower frequency. These results demonstrate that dexmedetomidine deepens sevoflurane anesthesia, and enhances α and θ bicoherences while shifting peak values of these bands to lower frequencies through regulating thalamo-cortical reverberation networks probably.

Single dose and chronic oral administration of cannabigerol and cannabigerolic acid-rich hemp extract in fed and fasted dogs: Physiological effect and pharmacokinetic evaluation

The use of cannabinoids in veterinary medicine has been increasing exponentially recently and there is little information regarding the pharmacokinetics of cannabinoids except for cannabidiol (CBD) and tetrahydrocannabinol (THC), with even more sparse information related to their native acid forms found in cannabis. Cannabigerol (CBG) is the precursor molecule to cannabinoid formation in the cannabis plant which may have medicinal properties as well, yet there are no publications related to CBG or the native cannabigerolic acid (CBGA) in companion animal species. The aim of this study was to investigate similar dosing of CBG and CBGA from hemp plants that have been used for cannabidiol pharmacokinetic studies. Administration in the fed and fasted state was performed to better understand absorption and retention of these unique hemp-derived cannabinoids in dogs. Results suggest that when providing a hemp-derived CBG/CBGA formulation in equal quantities, CBGA is absorbed approximately 40-fold better than CBG regardless of being given to fed or fasted dogs. After twice daily dosing for two weeks at 2 mg/kg in the fasted and then fed state, no differences in the mean serum CBG (5 ng/ml) or CBGA (250 ng/ml) serum concentrations were observed between states. Importantly, physical examination, complete blood counts, and serum chemistry evaluations over the two weeks suggest no adverse events during this short-term dosing trial.

An assessment of dexmedetomidine as an opioid-sparing agent after neonatal open thoracic and abdominal operations

OBJECTIVE

To evaluate the efficacy of dexmedetomidine as an opioid-sparing agent in infants following open thoracic or abdominal operations.

METHODS

Retrospective review of postoperative neonates who received IV acetaminophen with or without dexmedetomidine. The primary outcome was opioid dosage within the first ten postoperative days. Secondary outcomes included times to extubation, full feedings and discharge.

RESULTS

112 infants met inclusion criteria. Those managed with dexmedetomidine received 1.8-4.3 times more opioid on postoperative days 1-3, had longer times to extubation and trended towards longer lengths of hospital stay than infants who were not. Opioid was dosed >0.2 ME/kg on only 23% of days when the acetaminophen dose was >40 mg/kg/day and 10% of days when the acetaminophen dose was >45 mg/kg.

CONCLUSION

Dexmedetomidine may not be opioid sparing after major operations in neonates and its use delays recovery. IV acetaminophen dosed at 40 mg/kg/day or greater may yield the most substantial opioid-sparing effect.

Pneumothorax and Pneumomediastinum Complicating Organophosphate Poisoning: A Case Series of Complications Less Understood

Organophosphate compounds are used as insecticides in agricultural and domestic settings throughout the world. Acute organophosphorus (OP) poisoning is a major public health issue. Early diagnosis of OP poisoning and prompt atropinization can save lives. Respiratory failure may occur in patients with OP poisoning for many reasons, including aspiration of gastric contents, excessive secretions, pneumonia, and sepsis complicating acute respiratory distress syndrome. Till date, however, spontaneous pneumothorax and pneumomediastinum have not been reported in cases of OP poisoning. This report presents two similar cases of OP poisoning in which spontaneous pneumothorax and pneumomediastinum developed following OP ingestion.

Quantitative assessment of the central versus peripheral effect of intravenous clonidine using baroreflex equilibrium diagrams

Clonidine is a first-generation central antihypertensive that reduces sympathetic nerve activity (SNA). Although clonidine also exerts peripheral vasoconstriction, the extent to which this vasoconstriction offsets the centrally mediated arterial pressure (AP)-lowering effect remains unknown. In anesthetized rats (n = 8), we examined SNA and AP responses to stepwise changes in carotid sinus pressure under control conditions and after intravenous low-dose (2 μg/kg) and high-dose clonidine (5 μg/kg). In the baroreflex equilibrium diagram analysis, the operating-point AP under the control condition was 115.2 (108.5-127.7) mmHg [median (25th-75th percentile range)]. While the operating-point AP after low-dose clonidine was not significantly different with or without the peripheral effect, the operating-point AP after high-dose clonidine was higher with the peripheral effect than without [81.3 (76.2-98.2) mmHg vs. 70.7 (57.7-96.9), P < 0.05]. The vasoconstrictive effect of clonidine partly offset the centrally mediated AP-lowering effect after high-dose administration.

The safety of high-dose dexmedetomidine after cardiac surgery: a historical cohort study

PURPOSE

The off-label use of dexmedetomidine beyond the monograph-recommended maximum dose of 0.7 µg·kg^-1·hr^-1 is common in postoperative cardiac surgical units; however, limited data exist on the association of higher doses and adverse hemodynamic effects. We sought to compare the rate of hypotension or bradycardia in cardiac surgery patients receiving peak infusion doses below and above 0.7 µg·kg^-1·hr^-1 for any indication or duration.

METHODS

In this historical cohort study, we reviewed all patients who received dexmedetomidine infusion after cardiac surgery between June 2013 and July 2017 at a single centre. Regardless of the duration of exposure at the peak infusion dose, patients were categorized into high- or standard-dose groups using 0.7 µg·kg^-1·hr^-1 as the cutoff value. We compared rates of the primary composite outcome of hypotension or bradycardia, and secondary outcomes (i.e., arrhythmia and hyperglycemia) between groups using the two-proportion z test. Exploratory regression models were fitted to adjust for potential confounders.

RESULTS

The median [interquartile range (IQR)] peak infusion dose was 1.0 [1.0-1.4] µg·kg^-1·hr^-1 in the high-dose group (N = 121) and 0.5 [0.4-0.7] µg·kg^-1·hr^-1 in the standard-dose group (N = 124). The rates of the primary composite outcome were 73% and 65%, respectively (absolute risk difference, 8%; 95% confidence interval, -3 to 20; P = 0.17). There was no significant difference in primary or secondary outcomes between groups.

CONCLUSION

There was a high overall rate of hypotension or bradycardia in patients receiving dexmedetomidine after cardiac surgery; infusion rates below or above 0.7 µg·kg^-1·hr^-1 had similar rates of adverse hemodynamic events.

Comparison between dexmedetomidine and esketamine in pediatric dentistry surgery

BACKGROUND

Dexmedetomidine (D) and esketamine (K) are used for the sedation of pediatric dental surgery. This study was designed to compare the effect of intranasal D and K in producing moderate sedation for uncooperative pediatric dental patients.

METHODS

This prospective single-center cohort study was conducted at the Maternal and Child Health Hospital of Hubei Province after approval of the Medical Ethics Committee. One hundred and fifty American Society of Anesthesiologists (ASA) grade I and II patients aged 3-10 years who were uncooperative and could not be managed by conventional behavior management techniques were included in this study. Patients were classified into four groups. Group K was administered with esketamine (0.5 mg/kg), and group D was given D1 (1 µg/kg), D2 (1.5 µg/kg), or D3 (2.0 µg/kg) intranasally. The outcome measurements included the sedation level, changes in vital signs, sedation onset and recovery times, analgesia, behavior, and overall success.

RESULTS

The sedation onset time was significantly shorter for K and D3 compared with D1 and D2. The recovery time was fastest in group D1. The overall success rate was highest in group D3, followed by the D2, D1, and K groups; however, the difference between them was not significant. The intra-and postoperative pain scores in the D3 and K groups were significantly lower than those in the D1 group.

CONCLUSIONS

Intranasal D and K are effective in producing moderate sedation for uncooperative pediatric dental patients.