Do all sedatives promote biological sleep electroencephalogram patterns? A machine learning framework to identify biological sleep promoting sedatives using electroencephalogram.

BACKGROUND: Sedatives are commonly used to promote sleep in intensive care unit patients. However, it is not clear whether sedation-induced states are similar to the biological sleep. We explored if sedative-induced states resemble biological sleep using multichannel electroencephalogram (EEG) recordings. METHODS: Multichannel EEG datasets from two different sources were used in this study: (1) sedation dataset consisting of 102 healthy volunteers receiving propofol (N = 36), sevoflurane (N = 36), or dexmedetomidine (N = 30), and (2) publicly available sleep EEG dataset (N = 994). Forty-four quantitative time, frequency and entropy features were extracted from EEG recordings and were used to train the machine learning algorithms on sleep dataset to predict sleep stages in the sedation dataset. The predicted sleep states were then compared with the Modified Observer's Assessment of Alertness/ Sedation (MOAA/S) scores. RESULTS: The performance of the model was poor (AUC = 0.55-0.58) in differentiating sleep stages during propofol and sevoflurane sedation. In the case of dexmedetomidine, the AUC of the model increased in a sedation-dependent manner with NREM stages 2 and 3 highly correlating with deep sedation state reaching an AUC of 0.80. CONCLUSIONS: We addressed an important clinical question to identify biological sleep promoting sedatives using EEG signals. We demonstrate that propofol and sevoflurane do not promote EEG patterns resembling natural sleep while dexmedetomidine promotes states resembling NREM stages 2 and 3 sleep, based on current sleep staging standards.

Zona incerta mediates early life isoflurane-induced fear memory deficits.

The potential long-term effects of anesthesia on cognitive development, especially in neonates and infants, have raised concerns. However, our understanding of its underlying mechanisms and effective treatments is still limited. In this study, we found that early exposure to isoflurane (ISO) impaired fear memory retrieval, which was reversed by dexmedetomidine (DEX) pre-treatment. Measurement of c-fos expression revealed that ISO exposure significantly increased neuronal activation in the zona incerta (ZI). Fiber photometry recording showed that ZI neurons from ISO mice displayed enhanced calcium activity during retrieval of fear memory compared to the control group, while DEX treatment reduced this enhanced calcium activity. Chemogenetic inhibition of ZI neurons effectively rescued the impairments caused by ISO exposure. These findings suggest that the ZI may play a pivotal role in mediating the cognitive effects of anesthetics, offering a potential therapeutic target for preventing anesthesia-related cognitive impairments.

Determining the Optimal Dosage of Dexmedetomidine for Smooth Emergence in Older Patients Undergoing Spinal Surgery: A Study of 44 Cases.

BACKGROUND Emergence agitation, or delirium, occurs during early recovery from general anesthesia and involves disorientation, excitation, and uncontrolled physical movements. Dexmedetomidine is an alpha agonist that has sedative, anxiolytic, analgesic, and sympatholytic activities and is used as a continuous infusion to prevent emergence agitation. This study aimed to evaluate patients aged 65 years and older undergoing general anesthesia to determine the 90% effective dose (ED90) of dexmedetomidine continuous intraoperative infusion to prevent emergence agitation. MATERIAL AND METHODS We enrolled 44 patients aged 65 years and older undergoing spinal surgery under general anesthesia. Dexmedetomidine administration commenced 30 minutes before surgery completion, with a predetermined infusion dose (µg/kg/h), without a loading dose. The initial dose was 0.2 µg/kg/h, and subsequent step size was ±0.05 µg/kg/h. We tried to find ED90 of dexmedetomidine using the biased-coin design. Vital signs, extubation quality scores, extubation-related complications, and postoperative outcomes were monitored. RESULTS Dexmedetomidine ED90 for smooth emergence in older patients was 0.34 µg/kg/h. Peri-extubation vital signs remained within 20% of baseline values, without requiring pharmacological intervention. No hypoxia, hypoventilation, or post-extubation agitation occurred. In the recovery room, 1 patient briefly exhibited excitement but quickly calmed. Nine patients initially unresponsive in the recovery room fully awoke and were promptly discharged. CONCLUSIONS For older patients who are vulnerable to adverse effects of anesthetics and opioids, dexmedetomidine enables gentle awakening without adverse vital sign changes, respiratory depression, excessive sedation, or emergence agitation (ED90=0.34 µg/kg/h). Further studies should involve a larger patient cohort, considering diverse medical conditions in older individuals.

Effects of Ultrasound-Guided Thoracic Paravertebral Nerve Block Combined with Perineural or IV Dexmedetomidine on Acute and Chronic Pain After Thoracoscopic Resection of Lung Lesions: A Double-Blind Randomized Trial.

Background: Thoracic paravertebral block (TPVB) analgesia can be prolonged by local anesthetic adjuvants such as dexmedetomidine. This study aimed to evaluate the two administration routes of dexmedetomidine on acute pain and chronic neuropathic pain (NeuP) prevention compared with no dexmedetomidine. Methods: A total of 216 patients were randomized to receive TPVB using 0.4% ropivacaine alone (R Group), with perineural dexmedetomidine 0.5 µg·kg-1 (RD0.5 Group) or 1.0 µg·kg-1 (RD1.0 Group), or intravenous (IV) dexmedetomidine 0.5 µg·kg-1·h-1 (RDiv Group). The primary outcome was the incidence of chronic NeuP, defined as a Leeds Assessment of Neuropathic Symptoms and Signs (LANSS) pain score > 12 points at 3-month after surgery. Results: (1) For the primary outcome, RD0.5 Group and RD1.0 Group demonstrated a decreased incidence of chronic NeuP at 3-month after surgery; (2) Compared with R Group, RDiv Group, RD0.5 Group, and RD1.0 Group can reduce VAS scores at rest and movement and Prince-Henry Pain scores at 12 and 24-h after surgery, the consumption of oral morphine equivalent (OME) and improve QOD-15 at POD1; (3) Compared with RDiv Group, RD0.5 Group and RD1.0 Group can reduce VAS scores at rest and movement and Prince-Henry Pain scores at 12 and 24-h after surgery, the consumption of postoperative OME and improve QOD-15 at POD1; (4) Compared with RD0.5 Group, RD1.0 Group effectively reduced VAS scores at rest at 12 and 24-h after surgery, VAS scores in movement and Prince-Henry Pain scores at 12-h after surgery. However, RD1.0 Group showed an increased incidence of drowsiness. Conclusion: Perineural or IV dexmedetomidine are similarly effective in reducing acute pain, but only perineural dexmedetomidine reduced chronic NeuP. Moreover, considering postoperative complications such as drowsiness, perineural dexmedetomidine (0.5 µg·kg-1) may be a more appropriate choice. Clinical Trial Registration: Chinese Clinical Trial Registry (ChiCTR2200058982).

Influence of psychological factors and pain sensitivity on the efficacy of opioid-free anesthesia: A randomized clinical trial.

OBJECTIVE: This study aimed to investigate the effects of opioid-free anesthesia (OFA) in laparoscopic gastrectomy and identify the psychological factors that could influence the efficacy of OFA. METHOD: 120 patients undergoing laparoscopic gastrectomy were allocated to either the opioid-based anesthesia group (OA) (n = 60) or the OFA (n = 60) group. Remifentanil was administered to the OA group intraoperatively, whereas dexmedetomidine and lidocaine were administered to the OFA group. The interaction effect of the psychological factors on OFA was analyzed using the aligned rank transform for nonparametric factorial analyses. RESULTS: The opioid requirement for 24 h after surgery was lower in the OFA group than in the OA group (fentanyl equivalent dose 727 vs. 650 µg, p = 0.036). The effect of OFA was influenced by the pain catastrophizing scale (p = 0.041), temporal pain summation (p = 0.046), and pressure pain tolerance (p = 0.034). This indicates that patients with pain catastrophizing or high pain sensitivity significantly benefited from OFA, whereas patients without these characteristics did not. CONCLUSIONS: This study demonstrated that OFA with dexmedetomidine and lidocaine effectively reduced the postoperative 24-h opioid requirements following laparoscopic gastrectomy, which was modified by baseline pain catastrophizing and pain sensitivity. CLINICAL TRIAL REGISTRY: The study protocol was approved by the Institutional Review Board of Yonsei University Health System Gangnam Severance Hospital (#3-2021-0295) and registered at ClinicalTrials.gov (NCT05076903).

Dexmedetomidine improves the circulatory dysfunction of the glymphatic system induced by sevoflurane through the PI3K/AKT/ΔFosB/AQP4 pathway in young mice.

Multiple sevoflurane exposures may damage the developing brain. The neuroprotective function of dexmedetomidine has been widely confirmed in animal experiments and human studies. However, the effect of dexmedetomidine on the glymphatic system has not been clearly studied. We hypothesized that dexmedetomidine could alleviate sevoflurane-induced circulatory dysfunction of the glymphatic system in young mice. Six-day-old C57BL/6 mice were exposed to 3% sevoflurane for 2 h daily, continuously for 3 days. Intraperitoneal injection of either normal saline or dexmedetomidine was administered before every anaesthesia. Meanwhile the circulatory function of glymphatic system was detected by tracer injection at P8 and P32. On P30-P32, behavior tests including open field test, novel object recognition test, and Y-maze test were conducted. Primary astrocyte cultures were established and treated with the PI3K activator 740Y-P, dexmedetomidine, and small interfering RNA (siRNA) to silence ΔFosB. We propose for the first time that multiple exposure to sevoflurane induces circulatory dysfunction of the glymphatic system in young mice. Dexmedetomidine improves the circulatory capacity of the glymphatic system in young mice following repeated exposure to sevoflurane through the PI3K/AKT/ΔFosB/AQP4 signaling pathway, and enhances their long-term learning and working memory abilities.

Dexmedetomidine ameliorates x-ray-induced myocardial injury via alleviating cardiomyocyte apoptosis and autophagy.

BACKGROUND: Radiotherapy is a primary local treatment for tumors, yet it may lead to complications such as radiation-induced heart disease (RIHD). Currently, there is no standardized approach for preventing RIHD. Dexmedetomidine (Dex) is reported to have cardio-protection effects, while its role in radiation-induced myocardial injury is unknown. In the current study, we aimed to evaluate the radioprotective effect of dexmedetomidine in X-ray radiation-treated mice. METHODS: 18 male mice were randomized into 3 groups: control, 16 Gy, and 16 Gy + Dex. The 16 Gy group received a single dose of 16 Gy X-ray radiation. The 16 Gy + Dex group was pretreated with dexmedetomidine (30 µg/kg, intraperitoneal injection) 30 min before X-ray radiation. The control group was treated with saline and did not receive X-ray radiation. Myocardial tissues were collected 16 weeks after X-ray radiation. Hematoxylin-eosin staining was performed for histopathological examination. Terminal deoxynucleotidyl transferase dUTP nick-end labeling staining was performed to assess the state of apoptotic cells. Immunohistochemistry staining was performed to examine the expression of CD34 molecule and von Willebrand factor. Besides, western blot assay was employed for the detection of apoptosis-related proteins (BCL2 apoptosis regulator and BCL2-associated X) as well as autophagy-related proteins (microtubule-associated protein 1 light chain 3, beclin 1, and sequestosome 1). RESULTS: The findings demonstrated that 16 Gy X-ray radiation resulted in significant changes in myocardial tissues, increased myocardial apoptosis, and activated autophagy. Pretreatment with dexmedetomidine significantly protects mice against 16 Gy X-ray radiation-induced myocardial injury by inhibiting apoptosis and autophagy. CONCLUSION: In summary, our study confirmed the radioprotective effect of dexmedetomidine in mitigating cardiomyocyte apoptosis and autophagy induced by 16 Gy X-ray radiation.

Dexmedetomidine as a Short-Use Analgesia for the Immature Nervous System.

Pain management in neonates continues to be a challenge. Diverse therapies are available that cause loss of pain sensitivity. However, because of side effects, the search for better options remains open. Dexmedetomidine is a promising drug; it has shown high efficacy with a good safety profile in sedation and analgesia in the immature nervous system. Though dexmedetomidine is already in use for pain control in neonates (including premature neonates) and infants as an adjunct to other anesthetics, the question remains whether it affects the neuronal activity patterning that is critical for development of the immature nervous system. In this study, using the neonatal rat as a model, the pharmacodynamic effects of dexmedetomidine on the nervous and cardiorespiratory systems were studied. Our results showed that dexmedetomidine has pronounced analgesic effects in the neonatal rat pups, and also weakly modified both the immature network patterns of cortical and hippocampal activity and the physiology of sleep cycles. Though the respiration and heart rates were slightly reduced after dexmedetomidine administration, it might be considered as the preferential independent short-term therapy for pain management in the immature and developing brain.

Dexmedetomidine's Effects on the Livers and Kidneys of Rats with Pancreatic Ischemia-Reperfusion Injury.

Objective: Pancreatic surgeries inherently cause ischemia-reperfusion (IR) injury, affecting not only the pancreas but also distant organs. This study was conducted to explore the potential use of dexmedetomidine, a sedative with antiapoptotic, anti-inflammatory, and antioxidant properties, in mitigating the impacts of pancreatic IR on kidney and liver tissues. Methods: A total of 24 rats were randomly divided into four groups: control (C), dexmedetomidine (D), ischemia reperfusion (IR), and dexmedetomidine ischemia reperfusion (D-IR). Pancreatic ischemia was induced in the IR and D-IR groups. Dexmedetomidine was administered intraperitoneally to the D and D-IR groups. Liver and kidney tissue samples were subjected to microscopic examinations after hematoxylin and eosin staining. The levels of thiobarbituric acid reactive substances (TBARS), aryllesterase (AES), catalase (CAT), and glutathione S-transferase (GST) enzyme activity were assessed in liver and kidney tissues. The serum levels of aspartate aminotransferase (AST), alanine aminotransferase (ALT), blood urea nitrogen (BUN), and creatinine were measured. Results: A comparison of the groups revealed that the IR group exhibited significantly elevated TBARS (p < 0.0001), AES (p = 0.004), and CAT enzyme activity (p < 0.0001) levels in the liver and kidney compared to groups C and D. Group D-IR demonstrated notably reduced histopathological damage (p < 0.05) and low TBARS (p < 0.0001), AES (p = 0.004), and CAT enzyme activity (p < 0.0001) in the liver and kidney as well as low AST and ALT activity levels (p < 0.0001) in the serum compared to the IR group. Conclusion: The preemptive administration of dexmedetomidine before pancreatic IR provides significant protection to kidney and liver tissues, as evidenced by the histopathological and biochemical parameters in this study. The findings underscored the potential therapeutic role of dexmedetomidine in mitigating the multiorgan damage associated with pancreatic surgeries.

Effect of Oxycodone-Based Multimodal Analgesia on Visceral Pain After Major Laparoscopic Gastrointestinal Surgery: A Randomised, Double-Blind, Controlled Trial.

Purpose: Oxycodone is a potent µ- and κ-opioid receptor agonist that can relieve both somatic and visceral pain. We assessed oxycodone- vs sufentanil-based multimodal analgesia on postoperative pain following major laparoscopic gastrointestinal surgery. Methods: In this randomised double-blind controlled trial, 40 adult patients were randomised (1:1, stratified by type of surgery) to receive oxycodone- or sufentanil-based multimodal analgesia, comprising bilateral transverse abdominis plane blocks, intraoperative dexmedetomidine infusion, flurbiprofen axetil, and oxycodone- or sufentanil-based patient-controlled analgesia. The co-primary outcomes were time-weighted average (TWA) of visceral pain (defined as intra-abdominal deep and dull pain) at rest and on coughing during 0-24 h postoperatively, assessed using the numerical rating scale (0-10) with a minimal clinically important difference of 1. Results: All patients completed the study (median age, 64 years; 65% male) and had adequate postoperative pain control. The mean (SD) 24-h TWA of visceral pain at rest was 1.40 (0.77) in the oxycodone group vs 2.00 (0.98) in the sufentanil group (mean difference=-0.60, 95% CI, -1.16 to -0.03; P=0.039). Patients in the oxycodone group had a significantly lower 24-h TWA of visceral pain on coughing (2.00 [0.83] vs 2.98 [1.26]; mean difference=-0.98, 95% CI, -1.66 to -0.30; P=0.006). In the subgroup analyses, the treatment effect of oxycodone vs sufentanil on the co-primary outcomes did not differ in terms of age (18-65 years or >65 years), sex (female or male), or type of surgery (colorectal or gastric). Secondary outcomes (24-h TWA of incisional and shoulder pain, postoperative analgesic usage, rescue analgesia, adverse events, and patient satisfaction) were comparable between groups. Conclusion: For patients undergoing major laparoscopic gastrointestinal surgery, oxycodone-based multimodal analgesia reduced postoperative visceral pain in a statistically significant but not clinically important manner. Trial Registration: Chinese Clinical Trial Registry (ChiCTR2100052085).

Total intravenous anesthesia with Ketofol in rabbits: a comparison of the effects of constant rate infusion of midazolam, fentanyl or dexmedetomidine.

BACKGROUND: When inhalant anesthetic equipment is not available or during upper airway surgery, intravenous infusion of one or more drugs are commonly used to induce and/or maintain general anesthesia. Total intravenous anesthesia (TIVA) does not require endotracheal intubation, which may be more difficult to achieve in rabbits. A range of different injectable drug combinations have been used as continuous infusion rate in animals. Recently, a combination of ketamine and propofol (ketofol) has been used for TIVA in both human patients and animals. The purpose of this prospective, blinded, randomized, crossover study was to evaluate anesthetic and cardiopulmonary effects of ketofol total intravenous anesthesia (TIVA) in combination with constant rate infusion (CRI) of midazolam, fentanyl or dexmedetomidine in eight New Zealand White rabbits. Following IV induction with ketofol and endotracheal intubation, anesthesia was maintained with ketofol infusion in combination with CRIs of midazolam (loading dose [LD]: 0.3 mg/kg; CRI: 0.3 mg/kg/hr; KPM), fentanyl (LD: 6 µg/kg; CRI: 6 µg/kg/hr; KPF) or dexmedetomidine (LD: 3 µg/kg; CRI: 3 µg/kg/hr; KPD). Rabbits in the control treatment (KPS) were administered the same volume of saline for LD and CRI. Ketofol infusion rate (initially 0.6 mg kg- 1 minute- 1 [0.3 mg kg- 1 minute- 1 of each drug]) was adjusted to suppress the pedal withdrawal reflex. Ketofol dose and physiologic variables were recorded every 5 min. RESULTS: Ketofol induction doses were 14.9 ± 1.8 (KPM), 15.0 ± 1.9 (KPF), 15.5 ± 2.4 (KPD) and 14.7 ± 3.4 (KPS) mg kg- 1 and did not differ among treatments (p > 0.05). Ketofol infusion rate decreased significantly in rabbits in treatments KPM and KPD as compared with saline. Ketofol maintenance dose in rabbits in treatments KPM (1.0 ± 0.1 mg/kg/min) and KPD (1.0 ± 0.1 mg/kg/min) was significantly lower as compared to KPS (1.3 ± 0.1 mg/kg/min) treatment (p < 0.05). Ketofol maintenance dose did not differ significantly between treatments KPF (1.1 ± 0.3 mg/kg/min) and KPS (1.3 ± 0.1 mg/kg/min). Cardiovascular variables remained at clinically acceptable values but ketofol infusion in combination with fentanyl CRI was associated with severe respiratory depression. CONCLUSIONS: At the studied doses, CRIs of midazolam and dexmedetomidine, but not fentanyl, produced ketofol-sparing effect in rabbits. Mechanical ventilation should be considered during ketofol anesthesia, particularly when fentanyl CRI is used.

Comparison of the Safety and Efficacy of Remimazolam Besylate versus Dexmedetomidine for Patients Undergoing Fiberoptic Bronchoscopy: A Prospective, Randomized Controlled Trial.

Objective: Remimazolam besylate is a novel ultra-short-acting benzodiazepine that is rapidly hydrolyzed to zolpidem propionic acid by tissue lipases. We designed this study to compare the safety and efficacy of remimazolam besylate alfentanil versus dexmedetomidine-alfentanil for fiberoptic bronchoscopy (FB). Methods: One hundred and twenty patients undergoing FB into this prospective randomized controlled trial were divided into two groups. The anesthesia induction consisted of 6 mg/kg/h of remimazolam besylate in the RA group and 0.5 µg/kg of dexmedetomidine in the DA group. 1-2 mg/kg/h of remimazolam besylate or 0.2-0.7 µg/kg/h of dexmedetomidine were administered to maintain during FB. The lowest oxygen saturation, success rate of FB, hemodynamics, time metrics, bronchoscopy feasibility, drug dose requirements, patient and bronchoscopist satisfaction scores, occurrence of intraoperative awareness, number of patients willing to repeat FB with the same sedation regimen, and occurrence and severity of adverse events. Results: The lowest oxygen saturation during the FB was significantly higher in the RA group (P = 0.001). Compared with the variables in the DA group, peripheral oxygen saturation, systolic blood pressure, and diastolic blood pressure were significantly lower at T2 and T3 in the RA group (P < 0.05). Heart rates were significantly higher from T2 to T4 in the DA group (P < 0.05). More patients experienced bradycardia in the DA group (P = 0.041). Compared with time metrics in the DA group, the induction time, fully-alert time, and recovery room-leaving time were all significantly shorter in the RA group (P < 0.05). The bronchoscopy feasibility scores in the RA group were significantly lower at T2, whereas they were lower at T3 in the DA group (P < 0.05). Conclusion: Remimazolam besylate is superior to dexmedetomidine when combined with alfentanil during FB, promoting faster patients' recovery, better operative conditions and respiratory stability with similar rates of occurrence and severity of adverse events.

Dexmedetomidine Attenuates Inflammation in Elderly Patients Following Major Hepatobiliary and Pancreatic Surgery: A Randomized Clinical Trial.

Background: Dexmedetomidine (Dex) may have anti-inflammatory properties and potentially reduce the incidence of postoperative organ injury. Objective: To investigate whether Dex protects pulmonary and renal function via its anti-inflammatory effects in elderly patients undergoing prolonged major hepatobiliary and pancreatic surgery. Design and Setting: Between October 2019 and December 2020, this randomized controlled trial was carried out at a tertiary hospital in Chongqing, China. Patients: 86 patients aged 60-75 who underwent long-duration (> 4 hrs) hepatobiliary and pancreatic surgery without significant comorbidities were enrolled and randomly assigned into two groups at a 1:1 ratio. Interventions: Patients were given either Dex or an equivalent volume of 0.9% saline (Placebo) with a loading dose of 1 µg kg-1 for 10 min, followed by 0.5 µg kg-1 hr-1 for maintenance until the end of surgery. Main Outcome Measures: The changes in serum concentrations of interleukin-6 (IL-6) and tumour necrosis factor-α (TNF-α) were primary outcomes. Results: At one hour postoperatively, serum IL-6 displayed a nine-fold increase (P<0.05) in the Placebo group. Administration of Dex decreased IL-6 to 278.09 ± 45.43 pg/mL (95% CI: 187.75 to 368.43) compared to the Placebo group (P=0.019; 432.16 ± 45.43 pg/mL, 95% CI: 341.82 to 522.50). However, no significant differences in TNF-α were observed between the two groups. The incidence of postoperative acute kidney injury was twice as high in the Placebo group (9.30%) compared to the Dex group (4.65%), and the incidence of postoperative acute lung injury was 23.26% in the Dex group, lower than that in the Placebo group (30.23%), although there was no statistical significance between the two groups. Conclusion: Dex administration in elderly patients undergoing major hepatobiliary and pancreatic surgery reduces inflammation and potentially protects kidneys and lungs. Registration: Chinese Clinical Trials Registry, identifier: ChiCTR1900024162, on 28 June 2019.

Influence of intravenous fentanyl or dexmedetomidine infusions, combined with lidocaine and ketamine, on cardiovascular response, sevoflurane requirement and postoperative pain in dogs anesthetized for unilateral mastectomy.

OBJECTIVE: To compare the effects of constant rate infusions (CRI) of fentanyl or dexmedetomidine, combined with lidocaine and ketamine, on cardiovascular response during surgery, sevoflurane requirement and postoperative pain in dogs undergoing mastectomy. STUDY DESIGN: Prospective, randomized, blinded, clinical trial. ANIMALS: A total of 29 female dogs with mammary tumors. METHODS: Premedication consisted of intramuscular acepromazine and morphine. General anesthesia was induced with intravenous propofol and maintained with sevoflurane. Dogs were randomized to be administered intravenous DLK [dexmedetomidine 1 µg kg-1 loading dose (LD) and 1 µg kg-1 hour-1; lidocaine 2 mg kg-1 LD and 3 mg kg-1 hour-1; ketamine 1 mg kg-1 LD and 0.6 mg kg-1 hour-1; n = 14] or FLK (fentanyl 5 µg kg-1 LD and 9 µg kg-1 hour-1; same doses of lidocaine and ketamine; n = 15) during anesthesia. Cardiorespiratory variables and end-tidal sevoflurane (Fe'Sevo) were recorded during surgery. The number of dogs administered ephedrine to treat arterial hypotension [mean arterial pressure (MAP) < 60 mmHg] was recorded. Meloxicam was administered to both groups. Postoperative pain and rescue analgesia requirement were assessed for 24 hours using the short form of the Glasgow Composite Measure Pain Scale. Data were compared using a mixed effects model or a Mann-Whitney test. RESULTS: More dogs required ephedrine in FLK than in DLK (67% versus 7%). Heart rate was not significantly different between groups, whereas lower values of MAP (p ≤ 0.01) and Fe'Sevo (p = 0.018) were observed in FLK than in DLK. Rescue analgesia was administered to 2/15 dogs in FLK and 0/14 dogs in DLK. CONCLUSIONS AND CLINICAL RELEVANCE: Based on the cardiovascular response during surgery, intraoperative infusions of FLK and DLK provided adequate antinociception. Infusion of DLK provided greater stability of blood pressure. Both protocols resulted in minimal need for additional analgesia within 24 hours postoperatively.

The impact of Nrf2 knockout on the neuroprotective effects of dexmedetomidine in a mice model of cognitive impairment.

The nuclear factor erythroid 2-related factor 2 (Nrf2) signalling pathway represents a crucial intrinsic protective system against oxidative stress and inflammation and plays a significant role in various neurological disorders. However, the effect of Nrf2 signalling on the regulation of cognitive impairment remains unknown. Dexmedetomidine (DEX) has neuroprotective effects and can ameliorate lipopolysaccharide (LPS)-induced cognitive dysfunction. Our objective was to observe whether Nrf2 knockout influences the efficacy of DEX in improving cognitive impairment and to attempt to understand its underlying mechanisms. An LPS-induced cognitive dysfunction model in wild-type and Nrf2 knockout mice (Institute of Cancer Research background; male; 8-12 weeks) was used to observe the impact of DEX on cognitive dysfunction. LPS was intraperitoneally injected, followed by novel object recognition and morris water maze experiments 24 h later. Hippocampal tissues were collected for histopathological and molecular analyses. Our research findings suggest that DEX enhances the expression of NQO1, HO-1, PSD95, and SYP proteins in hippocampal tissue, inhibits microglial proliferation, reduces pro-inflammatory cytokines IL-1ß and TNF-ɑ, increases anti-inflammatory cytokine IL-10, and improves dendritic spine density, thereby alleviating cognitive dysfunction induced by LPS. However, the knockout of the Nrf2 gene negated the aforementioned effects of DEX. In conclusion, DEX alleviates cognitive deficits induced by LPS through mechanisms of anti-oxidative stress and anti-inflammation, as well as by increasing synaptic protein expression and dendritic spine density. However, the knockout of the Nrf2 gene reversed the effects of DEX. The Nrf2 signaling pathway plays a crucial role in the mitigation of LPS-induced cognitive impairment by DEX.

Perioperative analgesic effects of the erector spinae plane block with bupivacaine or bupivacaine-dexmedetomidine in dogs undergoing hemilaminectomy: A randomized controlled trial.

Objective: To compare the perioperative opioid requirements among dogs receiving an erector spinae plane (ESP) block with bupivacaine, with or without dexmedetomidine, and a control group. Animals and procedure: Thirty client-owned, healthy adult dogs undergoing hemilaminectomy were included in this randomized, prospective, blinded clinical study. Dogs were randomly assigned to 1 of 3 treatment groups: Group B, ESP block with bupivacaine; Group BD, ESP block with bupivacaine and dexmedetomidine; and Group C, control. Rescue intra- and postoperative analgesia consisted of fentanyl and methadone, respectively. Postoperative pain was evaluated using the short form of the Glasgow Composite Measure Pain Scale (CMPS-SF). Results: In Group BD, 0/10 dogs required intraoperative fentanyl, compared to 9/10 in Group C (P < 0.001), whereas 1/10 required postoperative methadone, compared to 9/10 in Group B (P = 0.003) and 10/10 in Group C (P < 0.001). The total amount of intraoperative fentanyl (µg/kg) was 0 (0 to 4) in Group B and 0 (0 to 0) in BD, compared to 6 (0 to 8) in C (P = 0.004 and P < 0.001, respectively). Postoperative methadone (mg/kg) required during the first 12 h was 0.5 (0 to 1.4) in Group B (P = 0.003) and 0 (0 to 0) in BD (P < 0.001), compared to C (P = 0.003 and P < 0.001, respectively). Conclusion: An ESP block with bupivacaine, with or without dexmedetomidine, was associated with a reduction in perioperative opioid consumption and provided effective acute pain control.

Effets analgésiques périopératoires du bloc des érecteurs du rachis avec de la bupivacaïne ou de la bupivacaïne-dexmédétomidine chez les chiens subissant une hémilaminectomie: un essai contrôlé randomisé. Objectif: Comparer les besoins périopératoires en opioïdes chez les chiens recevant un bloc des érecteurs de la colonne vertébrale (ESP) avec de la bupivacaïne, avec ou sans dexmédétomidine, et un groupe témoin. Animaux et procédure: Trente chiens adultes en bonne santé appartenant à des clients subissant une hémilaminectomie ont été inclus dans cette étude clinique randomisée, prospective et en aveugle. Les chiens ont été répartis au hasard dans 1 des 3 groupes de traitement: groupe B, bloc ESP avec bupivacaïne; groupe BD, bloc ESP avec bupivacaïne et dexmédétomidine; et groupe C, témoin. L'analgésie de secours peropératoire et postopératoire consistait respectivement en fentanyl et en méthadone. La douleur postopératoire a été évaluée à l'aide du formulaire abrégé de l'échelle de mesure de la douleur de Glasgow (CMPS-SF). Résultats: Dans le groupe BD, 0/10 chiens ont eu besoin de fentanyl peropératoire, contre 9/10 dans le groupe C (P < 0,001), tandis que 1/10 ont eu besoin de méthadone postopératoire, contre 9/10 dans le groupe B (P = 0,003) et 10/10 dans le groupe C (P < 0,001). La quantité totale de fentanyl peropératoire (µg/kg) était de 0 (0 à 4) dans le groupe B et de 0 (0 à 0) dans le groupe BD, contre 6 (0 à 8) dans le groupe C (P = 0,004 et P < 0,001, respectivement). La méthadone postopératoire (mg/kg) nécessaire au cours des 12 premières heures était de 0,5 (0 à 1,4) dans le groupe B (P = 0,003) et de 0 (0 à 0) dans le groupe BD (P < 0,001), par rapport au groupe C (P = 0,003). et P < 0,001, respectivement). Conclusion: Un bloc ESP avec de la bupivacaïne, avec ou sans dexmédétomidine, a été associé à une réduction de la consommation peropératoire d'opioïdes et a permis un contrôle efficace de la douleur aiguë.(Traduit par Dr Serge Messier).

Combining melatonin with dexmedetomidine improves anesthesia in rats.

Melatonin (ML) and dexmedetomidine (DM) are used separately as anesthetic premedication or as an anesthetic in humans and laboratory animals. In this study, we aimed to investigate the anesthetic properties of both drugs combined. The anesthetic effects of several combinations of ML (50 and 100 mg/kg) and DM (50 and 100 µg/kg) were evaluated in rats by observing behavioral manifestations and recording the duration and depth of anesthesia. Five anesthetic intervals were established according to the loss and recovery of reflexes. While each individual drug did not induce an appropriate anesthetic effect at the tested doses, ML50 + DM100, ML100 + DM50 and ML100 + DM100 combinations resulted in surgical anesthesia intervals of 60 to 360 min. Together, our results point that the use of ML allows to decrease the dose of DM, reducing the unwanted anesthetic effects of this α2-agonist.

Reversal of lipopolysaccharide-induced cardiomyocyte apoptosis via α7nAChR by dexmedetomidine.

This study aims to analyze the reversal of lipopolysaccharide (LPS)-induced cardiomyocyte apoptosis via α7nAChR by dexmedetomidine (Dex), so as to provide references for clinical treatment of myocardial disorders in the future. First, the research team divided cardiomyocytes (H9C2) were divided into a control group (normal culture), an LPS group (LPS-induced injury model), and an experimental group (pretreated with Dex before LPS induction). Subsequently, lactate dehydrogenase (LDH) and cell activity were detected, and the research team found that the LDH content of the control, experimental and LPS groups were in ascending order (P<0.05). The cell viability decreased and apoptosis increased in the LPS group, with cells mainly concentrating in the G2-M phase; the viability increased and apoptosis decreased in the experimental group, with blocked G1-G0 phase (P<0.05). This demonstrates that Dex can reverse LPS-induced apoptosis in cardiomyocytes. Subsequently, the research group also detected the expression of α7nAChR and NF-κB/AKT pathway, and it was seen that the expression of α7nAChR in the LPS group was higher than that in the control group, with activated NF-κB/AKT pathway; the α7nAChR expression in the experimental group was further elevated, but the NF-κB/AKT pathway was inhibited (P<0.05). The effects of Dex on cardiomyocytes were seen to be related to the α7nAChR and NF-κB/AKT pathways.

Dexmedetomidine alleviates acute postoperative anxiety in rats by suppressing the NF-ĸB pathway.

Evidence suggests that surgical procedures can effect the central nervous system and lead to changes in mood and behavior, rarely understood about the role of acute inflammation in promoting acute anxiety postoperatively. This study was designed to explore the possible mechanism of dexmedetomidine (DEX, a2-adrenergic receptor agonist) for reducing acute postoperative anxiety, which may be related to the activation of nuclear factor kappa B (NF-κB) and downstream signal pathway in the hippocampus. Experiments were conducted with rat, the elevated plus-maze and open field test were performed to evaluate anxiety-like behavior. Inhibit DEX with Atipamezole (AT, α2-adrenergic receptor antagonist) and inhibit NF-κB with Pyrrolidinedithiocarbamate (PDTC, inhibit phosphorylation of IκB, prevent the activation of NF-κB), the level of interleukin-6 (IL-6), IL-1ß, IL-10 and Tumor necrosis factor-α (TNF-α); the nuclear translocation of NF-κB in the hippocampus and anxiety-like behavior were measured. Rats exhibited anxiety-like behavior at 6h and 12h after surgery. Preoperative administration of DEX significantly alleviated postoperative anxiety-like behavior. DEX premedication inhibited the nuclear translocation of NF-κB alleviate acute postoperative anxiety. These findings are the first to show that acute postoperative anxiety may be related to NF-κB nuclear translocation in the hippocampus in rats, which can be alleviated by DEX premedication.

Dexmedetomidine inhibited arrhythmia susceptibility to adrenergic stress in RyR2R2474S mice through regulating the coupling of membrane potential and intracellular calcium.

BACKGROUND: Dexmedetomidine (DEX), a highly selective α2-adrenoceptor agonist, can decrease the incidence of arrhythmias, such as catecholaminergic polymorphic ventricular tachycardia (CPVT). However, the underlying mechanisms by which DEX affects cardiac electrophysiological function remain unclear. METHODS: Ryanodine receptor (RyR2) heterozygous R2474S mice were used as a model for CPVT. WT and RyR2R2474S/+ mice were treated with isoproterenol (ISO) and DEX, and electrocardiograms were continuously monitored during both in vivo and ex vivo experiments. Dual-dye optical mapping was used to explore the anti-arrhythmic mechanism of DEX. RESULTS: DEX significantly reduced the occurrence and duration of ISO-induced of VT/VF in RyR2R2474S/+ mice in vivo and ex vivo. DEX remarkably prolonged action potential duration (APD80) and calcium transient duration (CaTD80) in both RyR2R2474S/+ and WT hearts, whereas it reduced APD heterogeneity and CaT alternans in RyR2R2474S/+ hearts. DEX inhibited ectopy and reentry formation, and stabilized voltage-calcium latency. CONCLUSION: DEX exhibited an antiarrhythmic effect through stabilizing membrane voltage and intracellular Ca2+. DEX can be used as a beneficial perioperative anesthetic for patients with CPVT or other tachy-arrhythmias.