Intravenous ketamine for emergency department treatment of suicidal ideation in a paediatric population: protocol for a double-blind, randomised, placebo-controlled, parallel-arm pilot trial (KSI study).

INTRODUCTION: Suicidal ideation (SI) is a common and severe cause of morbidity in adolescents. Patients frequently present to the emergency department (ED) for care, yet there is no acute therapeutic intervention for SI. A single dose of intravenous ketamine has demonstrated efficacy in rapidly reducing SI in adults; however, ketamine has not been studied in paediatrics. We aim to determine the feasibility of a trial of a single intravenous ketamine dose to reduce SI for patients in the paediatric ED. METHODS AND ANALYSIS: This will be a single-centre, double-blind, randomised, placebo-controlled, parallel-arm pilot trial of intravenous ketamine for ED treatment of SI in a paediatric population. INTERVENTION: one intravenous dose of 0.5 mg/kg of ketamine (max 50 mg), over 40 min. Placebo: one intravenous dose of 0.5 mL/kg (max 50 mL) of normal saline, over 40 min. Participants will be randomised in a 1:1 ratio. SI severity will be measured at baseline, 40 min, 80 min, 120 min, 24 hours and 7 days. We aim to recruit 20 participants. The primary feasibility outcome is the proportion of eligible patients who complete the study protocol. We will pilot three SI severity tools and explore the efficacy, safety and tolerability of the intervention. ETHICS AND DISSEMINATION: This study will be conducted according to Canadian Biomedical Research Tutorial, international standards of Good Clinical Practice and the Health Canada, Food and Drug Act, Part C, Division 5. The study documents have been approved by the CHEO Research Institute Research Ethics Board (CHEO REB (23/02E)). Participants must provide free and informed consent to participate. If incapable due to age, assenting participants with parental/legal guardian consent may participate. On completion, we will endeavour to present results at international conferences, and publish the results in a peer-reviewed journal. Participants will receive a results letter. TRIAL REGISTRATION NUMBER: NCT05468840.

Effect of esketamine combined with dexmedetomidine on delirium in sedation for mechanically ventilated ICU patients: protocol for a nested substudy within a randomized controlled trial.

BACKGROUND: Use of sedatives and analgesics is associated with the occurrence of delirium in critically ill patients receiving mechanical ventilation. Dexmedetomidine reduces the occurrence of delirium but may cause hypotension, bradycardia, and insufficient sedation. This substudy aims to determine whether the combination of esketamine with dexmedetomidine can reduce the side effects and risk of delirium than dexmedetomidine alone in mechanically ventilated patients. METHODS: This single-center, randomized, active-controlled, superiority trial will be conducted at The First Affiliated Hospital of Nanjing Medical University. A total of 134 mechanically ventilated patients will be recruited and randomized to receive either dexmedetomidine alone or esketamine combined with dexmedetomidine, until extubation or for a maximum of 14 days. The primary outcome is the occurrence of delirium, while the second outcomes include the number of delirium-free days; subtype, severity, and duration of delirium; time to first onset of delirium; total dose of vasopressors and antipsychotics; duration of mechanical ventilation; ICU and hospital length of stay (LOS); accidental extubation, re-intubation, re-admission; and mortality in the ICU at 14 and 28 days. DISCUSSION: There is an urgent need for a new combination regimen of dexmedetomidine due to its evident side effects. The combination of esketamine and dexmedetomidine has been applied throughout the perioperative period. However, there is still a lack of evidence on the effects of this regimen on delirium in mechanically ventilated ICU patients. This substudy will evaluate the effects of the combination of esketamine and dexmedetomidine in reducing the risk of delirium for mechanically ventilated patients in ICU, thus providing evidence of this combination to improve the short-term prognosis. The study protocol has obtained approval from the Medical Ethics Committee (ID: 2022-SR-450). TRIAL REGISTRATION: ClinicalTrials.gov: NCT05466708, registered on 20 July 2022.

The anesthetic management of a child with ohtahara syndrome and severe stridor: a case report.

BACKGROUND: Ohtahara syndrome is a progressive developmental and epileptic encephalopathy that manifests in the early infantile period. This rare condition is characterized by intractable seizures, psychomotor retardation, and poor prognosis. To date, there are a handful of case reports regarding the anesthetic management of children with Ohtahara syndrome. However, limited reports exist of patients with Ohtahara syndrome who present with difficult airways. This report describes our airway findings and general anesthetic management of a pediatric patient with Ohtahara syndrome undergoing diagnostic bronchoscopy for severe inspiratory stridor. CASE PRESENTATION: A 14-month-old, 9 kg, male patient with Ohtahara syndrome presented with a year-long history of severe inspiratory stridor and was scheduled for bronchoscopy with lavage. On exam, the patient had noisy breathing, was non-verbal with developmental delay, and had poor head control with significant central hypotonia. The patient was induced with ketamine and general anesthesia was maintained with propofol. Bronchoscopic evaluation was completed uneventfully and revealed a diagnosis of laryngotracheomalacia. The patient's breathing was maintained spontaneously throughout the procedure and no seizures were noted. In the post anesthesia care unit, the patient's respiratory and cardiovascular function were stable. CONCLUSIONS: This report documents the unusual finding of severe inspiratory stridor in a 14-month-old child diagnosed with Ohtahara syndrome and our anesthetic management during their diagnostic bronchoscopy. Currently, documentation of complex airway pathology present in patients with Ohtahara syndrome is limited and should be further evaluated. This will assist pediatric anesthesiologists as these patients may require careful preoperative assessment, thoughtful airway management, and surgical alternatives on standby.

Comparing different postoperative sedation strategies for patients in the intensive care unit after cardiac surgery: A systematic review of randomized controlled trials and network meta-analysis.

BACKGROUND: Various postoperative sedation protocols with different anaesthetics lead to profound effects on the outcomes for post-cardiac surgery patients. However, a comprehensive analysis of optimal postoperative sedation strategies for patients in the intensive care unit (ICU) after cardiac surgery is lacking. METHODS: We systematically searched for randomized controlled trials (RCTs) in databases including PubMed and Embase. The primary outcome measured the duration of mechanical ventilation (MV) in the ICU, and the secondary outcome encompassed the length of stay (LOS) in the ICU and hospital and the monitoring adverse events. RESULTS: The literature included 18 RCTs (1652 patients) with 13 sedation regimens. Dexmedetomidine plus ketamine and sevoflurane were associated with a significantly reduced duration of MV when compared with propofol. Our results also suggested that dexmedetomidine plus ketamine may associated with a shorter LOS in ICU, and sevoflurane associated with a shorter LOS in the hospital, respectively. CONCLUSIONS: The combination of dexmedetomidine and ketamine seems to be a better option for adult patients needing sedation after cardiac surgery, and the incidence of side effects is lower with dexmedetomidine. These findings have potential implications for medication management in the perioperative pharmacotherapy of cardiac surgery patients.

Effects of Low-Dose Ketamine Infusion on the Positive and Negative Domains of Hopelessness and Suicidal Thoughts.

Background: Low-dose ketamine infusion has been demonstrated to exert antisuicidal effects on patients with treatment-resistant depression (TRD) and strong suicidal ideation. Although evidence suggests an association between hopelessness and suicidality, very few studies have investigated the antihopelessness effects of ketamine.Methods: This study included 84 patients with TRD and strong suicidal ideation. The diagnosis of depression was based on the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition, diagnostic criteria for major depressive disorder. They were randomly assigned to receive a single infusion of either 0.5 mg/kg ketamine or 0.045 mg/kg midazolam. Hopelessness and suicidal symptoms were assessed at baseline, at 240 minutes postinfusion, and on Days 2, 3, 7, and 14 postinfusion. The assessments were performed using the self-report Beck Hopelessness Scale (BHS) and Positive and Negative Suicide Ideation Inventory (PANSI). The analysis focused on the positive and negative domains of the BHS and PANSI, respectively. The clinical trial was conducted between August 15, 2018, and November 30, 2021.Results: Statistical analyses performed using a generalized linear model revealed that the ketamine group had significantly higher PANSI-positive (P = .008) and lower PANSI-negative (P = .015) suicidal ideation scores on Day 2 postinfusion than did the midazolam group. At 240 minutes postinfusion, the ketamine group had significantly lower BHS-negative domain scores than did the midazolam group (P = .031). Notably, the observed ketamine-induced reduction in hopelessness at 240 minutes postinfusion was associated with its antisuicidal effect on Day 2 postinfusion.Discussion: A single infusion of low-dose ketamine resulted in a brief (∼4 hours) yet significant reduction in hopelessness. Subjective antisuicidal effects of ketamine were noted on Day 2 postinfusion. Further studies are needed to elucidate the neuromechanisms underlying the antihopelessness and antisuicidal effects of ketamine.Trial Registration: UMIN Clinical Trials Registry identifiers: UMIN000033916 and UMIN000033760.

Common functional mechanisms underlying dynamic brain network changes across five general anesthetics: A rat fMRI study.

BACKGROUND: Reversible loss of consciousness is the primary therapeutic endpoint of general anesthesia; however, the drug-invariant mechanisms underlying anesthetic-induced unconsciousness are still unclear. This study aimed to investigate the static, dynamic, topological and organizational changes in functional brain network induced by five clinically-used general anesthetics in the rat brain. METHOD: Male Sprague-Dawley rats (n = 57) were randomly allocated to received propofol, isoflurane, ketamine, dexmedetomidine, or combined isoflurane plus dexmedetomidine anesthesia. Resting-state functional magnetic resonance images were acquired under general anesthesia and analyzed for changes in dynamic functional brain networks compared to the awake state. RESULTS: Different general anesthetics induced distinct patterns of functional connectivity inhibition within brain-wide networks, resulting in multi-level network reorganization primarily by impairing the functional connectivity of cortico-subcortical networks as well as by reducing information transmission capacity, intrinsic connectivity, and network architecture stability of subcortical regions. Conversely, functional connectivity and topological properties were preserved within cortico-cortical networks, albeit with fewer dynamic fluctuations under general anesthesia. CONCLUSIONS: Our findings highlighted the effects of different general anesthetics on functional brain network reorganization, which might shed light on the drug-invariant mechanism of anesthetic-induced unconsciousness.

A randomized controlled pilot study of daily intravenous ketamine over three days for treatment-resistant depression.

BACKGROUND: Studies have confirmed the rapid antidepressant action of ketamine in depressive episodes. Nevertheless, a standardized procedure for the delivery of ketamine infusion in individuals suffering from treatment-resistant depression, particularly in terms of infusion frequency and total dosage, remains undetermined. In addition, an efficacious ketamine regimen for persistent pain management involved a continuous 10-day infusion period with no notable adverse effects. Consequently, the primary objective of this study was to evaluate the antidepressant capacity of consecutive ketamine infusions spanning over three successive days, the duration of therapeutic response, and the overall safety profile of the treatment. METHODS: In this randomized controlled trial, participants aged 18-64 with treatment-resistant depression were randomized to receive either intravenous ketamine or midazolam (used as an active placebo) for 40 min daily over three consecutive days. Statistical analysis using repeated measures ANOVA was employed to assess the changes in the total score of the Montgomery-Åsberg Depression Rating Scale (MADRS) and the clinical global impression-Severity from the initial assessment to 10 and 31 days post-infusion. Additionally, the duration of response and remission was evaluated using Kaplan-Meier survival analysis. RESULTS: Out of 33 randomized participants, 20 underwent the treatment as planned. By day 10th, the ketamine group had a mean reduction in MADRS score of 12.55 (95% CI = 6.70-18.09), whereas the midazolam group had a decrease of 17.22 (95% CI = 11.09-23.36). This pattern continued to day 31, with ketamine showing a mean score decrease of 13.73 (95% CI = 7.54-19.91) and midazolam a fall of 12.44 (95% CI = 5.61-19.28). Both treatments were well tolerated, with dissociative symptoms in the ketamine group being temporary and ceasing by the end of each infusion. CONCLUSION: Intravenous ketamine given for three consecutive days did not show a notable antidepressant advantage when compared to the active placebo midazolam, highlighting the need for further research into effective treatments schedules for treatment-resistant depression. TRIAL REGISTRATION: NCT05026203, ClinicalTrials.gov, registered on 24/08/2021.

Effects of perioperative application of esketamine on postpartum depression in cesarean section: A systematic review and meta-analysis.

BACKGROUND: To evaluate the effect of perioperative esketamine administration on postpartum depression in pregnant women undergoing cesarean section. METHODS: Data sources was PubMed, Embase, Web of Science, and Cochrane Library from inception to February 1, 2024. Randomized controlled trials in pregnant women undergoing cesarean section were selected and compared to the use of esketamine in the perioperative period. The primary outcome measure was the incidence of postpartum maternal depression. Preferred reporting items for systematic reviews and meta-analyses were used. Data pooled by random-effects models are presented as risk ratios (RR) (95% confidence intervals, 95% CI) or mean differences (95% CI). This review was registered in PROSPERO (ID: CRD42023431197). RESULTS: We included 8 studies with a total of 1655 participants. The quality of the studies was rated high or unclear. Seven studies involving 1485 participants reported the incidence of postpartum depression. Compared with pregnant women undergoing cesarean section without the use of esketamine, those using esketamine in the perioperative period showed a 48% decreased risk of developing postpartum depression (RR: 0.52, 95% CI: 0.35-0.79) and a 1.43-point reduction in EPDS (Edinburgh Postnatal Depression Scale) (mean difference: -1.43, 95% CI: -2.32 to -0.54). For immediate intraoperative adverse reactions, the application of esketamine caused maternal nausea and vomiting (RR: 2.16, 95% CI: 1.22-3.81), dizziness (RR: 6.11, 95% CI: 1.49-24.98), and hallucinations (RR: 6.83, 95% CI: 1.57-29.68) compared to no esketamine use. CONCLUSIONS: Perioperative use of esketamine in pregnant women undergoing cesarean section may reduce postpartum depression and increase intraoperative adverse reactions, but has no significant effect on postoperative adverse reactions.

Study on the antidepressant activity of (2R,6R; 2S,6S)-Hydroxynorketamine (HNK) and its derivatives.

OBJECTIVE: This study mainly explores (2R,6R; 2S,6S)-HNK and its compounds whether there are antidepressant effects. METHODS: Four HNK compounds were obtained from 2-(Chlorophenyl) Cyclopentylmethanone. Forced swimming test, locomotor sensitization test, and conditioned location preference test were used to screen the antidepressant activity of the synthesized target compounds. RESULTS: In the case of 10 mg HNK treatment, compared with saline, the immobile time of mice in the HNK group, I5 group and I6 group at 1 h and 7 days had statistical significance. In the case of 10 mg HNK treatment, compared with saline, the immobile time of compound C and D groups in the glass cylinder area was significantly different. In the locomotor sensitization test, the movement distance of compound C and D groups on day 15 and day 7 mice increased significantly compared with the first day. In the conditioned place preference experiment, compound C and compound D induced conditioned place preference in mice compared with the Veh group. CONCLUSION: The results of the forced swimming test, locomotor sensitization test, and conditioned location preference test showed that compounds C and D may have certain anti-depressant activity. However, HNK exerts a rapid and significant antidepressant effect within 1 week, but the duration is short.

Effects of esketamine on depression-like behavior and dendritic spine plasticity in the prefrontal cortex neurons of spared nerve injury-induced depressed mice.

The present study utilized the spared nerve injury (SNI) to create a mouse model of depression to investigate the impact of esketamine on depressive-like behaviors, on the expression of PSD-95 and CRMP2 proteins, and on changes in neuronal dendritic spine plasticity in the prefrontal cortex (PFC). Depressive-like behavioral tests were performed 1 h after esketamine treatment, and the PFC tissues were obtained on the fourth day after completing the behavioral tests. Then, dendritic spine density and morphology in the PFC were measured using Golgi staining, and CRMP2 and PSD-95 proteins were obtained from PFC tissue by western blotting. The results of this study showed that esketamine significantly increased the immobility time in the forced swimming test and tail suspension test. In the open field test, esketamine increased the time spent in the open arms, the time spent in the central area, and the total distance covered. It also increased the protein expression levels of CRMP2 and PSD-95 in addition to the total and mature dendritic spine density of the PFC in SNI-depressed mice. Esketamine can significantly improve depression-like behaviors in SNI-depressed mice and promote an increase in dendritic spine density and maturation in the PFC. These effects may be associated with changes in CRMP2 and PSD-95 expression.

Esketamine combined with a mindfulness-based intervention for individuals with alcohol problems.

BACKGROUND: Alcohol use disorder (AUD) is a major public health issue, posing harmful consequences for individuals and society. Recent advances in addiction research have highlighted the therapeutic potential of ketamine-assisted therapy for AUD. However, the exact mechanisms underlying its effectiveness remain unknown. AIMS: This double-blind, pilot study aimed to investigate esketamine combined with mindfulness-based intervention (MBI) to examine whether esketamine enhances engagement in MBI for individuals with alcohol misuse problems and whether enhanced engagement has any impact on alcohol-related outcomes. METHODS: In all, 28 individuals with alcohol problems were randomly assigned to receive sublingual esketamine hydrochloride (AWKN002: 115.1 mg) or vitamin C (placebo) in an oral thin film and took part in 2 weeks of daily MBI. Participants were assessed on various self-report measures, including mindfulness, engagement in MBI (physical and psychological), alcohol cravings and consumption. RESULTS: Esketamine enhanced psychological engagement with a daily MBI, compared to placebo, and led to transient decreases in alcohol cravings. Esketamine also resulted in significantly greater mystical experiences and dissociative states compared to placebo. CONCLUSIONS: The findings suggest that esketamine may improve treatment outcomes when combined with mindfulness-based therapies through its ability to increase engagement with meditative practice.

Chronic Neuropathic Pain and Comorbid Depression Syndrome: From Neural Circuit Mechanisms to Treatment.

Chronic neuropathic pain and comorbid depression syndrome (CDS) is a major worldwide health problem that affects the quality of life of patients and imposes a tremendous socioeconomic burden. More than half of patients with chronic neuropathic pain also suffer from moderate or severe depression. Due to the complex pathogenesis of CDS, there are no effective therapeutic drugs available. The lack of research on the neural circuit mechanisms of CDS limits the development of treatments. The purpose of this article is to provide an overview of the various circuits involved in CDS. Notably, activating some neural circuits can alleviate pain and/or depression, while activating other circuits can exacerbate these conditions. Moreover, we discuss current and emerging pharmacotherapies for CDS, such as ketamine. Understanding the circuit mechanisms of CDS may provide clues for the development of novel drug treatments for improved CDS management.

Treatment of Brachioradial Pruritus: A Tertiary Center Retrospective Analysis.

This retrospective study investigates the efficacy of 2 treatment regimens, pregabalin alone versus pregabalin combined with ketamine, amitriptyline, and lidocaine cream, in reducing itch in patients with brachioradial pruritus at a tertiary care center. Electronic medical records of 64 brachioradial pruritus patients seen at the University of Miami Itch Center were analyzed. A significant reduction in itch scores was seen with both treatments, with no significant difference between the groups. A small number of patients experienced adverse effects, including drowsiness and weight gain with pregabalin and skin irritation with ketamine, amitriptyline, and lidocaine cream. Ultimately, our findings underscore the potential of utilizing combined therapy for difficult-to-treat brachioradial pruritus cases and implementing individualized approaches for managing neuropathic pruritus. Further controlled clinical trials are needed to establish optimal treatment protocols.

Adolescent administration of ketamine impairs excitatory synapse formation onto parvalbumin-positive GABAergic interneurons in mouse prefrontal cortex.

Ketamine, an N-methyl-d-aspartate (NMDA) receptor antagonist, induces deficits in cognition and information processing following chronic abuse. Adolescent ketamine misuse represents a significant global public health issue; however, the neurodevelopmental mechanisms underlying this phenomenon remain largely elusive. This study investigated the long-term effects of sub-chronic ketamine (Ket) administration on the medial prefrontal cortex (mPFC) and associated behaviors. In this study, Ket administration during early adolescence displayed a reduced density of excitatory synapses on parvalbumin (PV) neurons persisting into adulthood. However, the synaptic development of excitatory pyramidal neurons was not affected by ketamine administration. Furthermore, the adult Ket group exhibited hyperexcitability and impaired socialization and working memory compared to the saline (Sal) administration group. These results strongly suggest that sub-chronic ketamine administration during adolescence results in functional deficits that persist into adulthood. Bioinformatic analysis indicated that the gene co-expression module1 (M1) decreased expression after ketamine exposure, which is crucial for synapse development in inhibitory neurons during adolescence. Collectively, these findings demonstrate that sub-chronic ketamine administration irreversibly impairs synaptic development, offering insights into potential new therapeutic strategies.

(R)-(-)-Ketamine: The Promise of a Novel Treatment for Psychiatric and Neurological Disorders.

NMDA receptor antagonists have potential for therapeutics in neurological and psychiatric diseases, including neurodegenerative diseases, epilepsy, traumatic brain injury, substance abuse disorder (SUD), and major depressive disorder (MDD). (S)-ketamine was the first of a novel class of antidepressants, rapid-acting antidepressants, to be approved for medical use. The stereoisomer, (R)-ketamine (arketamine), is currently under development for treatment-resistant depression (TRD). The compound has demonstrated efficacy in multiple animal models. Two clinical studies disclosed efficacy in TRD and bipolar depression. A study by the drug sponsor recently failed to reach a priori clinical endpoints but post hoc analysis revealed efficacy. The clinical value of (R)-ketamine is supported by experimental data in humans and rodents, showing that it is less sedating, does not produce marked psychotomimetic or dissociative effects, has less abuse potential than (S)-ketamine, and produces efficacy in animal models of a range of neurological and psychiatric disorders. The mechanisms of action of the antidepressant effects of (R)-ketamine are hypothesized to be due to NMDA receptor antagonism and/or non-NMDA receptor mechanisms. We suggest that further clinical experimentation with (R)-ketamine will create novel and improved medicines for some of the neurological and psychiatric disorders that are underserved by current medications.

Role of Electroconvulsive Therapy, Ketamine Infusion, and Deep Repetitive Transcranial Magnetic Stimulation in Treatment-Resistant Bipolar Depression: A Case Report.

Background and Objectives: Options for treatment-resistant bipolar depression (TRBPD) are limited. Electroconvulsive therapy (ECT) has shown efficacy in TRBPD. However, the cognitive deficits and memory concerns associated with ECT are problematic for a significant number of patients. It remains unclear what the next step is for patients with TRBPD who fail ECT. Materials and Methods: In this case report, we present a patient with TRBPD who sequentially received 12 sessions of brief-pulse right unilateral ECT, 22 sessions of ketamine infusion at 0.5-0.75 mg/kg for 40 min, and 39 sessions of deep repetitive transcranial magnetic stimulation (dTMS). Results: The patient had some benefit from ECT, but declined continuation of ECT due to memory concerns. The patient tolerated ketamine infusion well but had limited benefit. However, the patient responded well to acute treatment with dTMS and maintained relative stability for more than 2 years. Conclusions: This case suggests that patients with TRBPD who fail ECT and/or ketamine infusion might benefit from dTMS.

Methadone in combination with magnesium, ketamine, lidocaine, and dexmedetomidine improves postoperative outcomes after coronary artery bypass grafting: an observational multicentre study.

BACKGROUND: An optimal pharmacological strategy for fast-track cardiac anesthesia (FTCA) is unclear. This study evaluated the effectiveness and safety of an FTCA program using methadone and non-opioid adjuvant infusions (magnesium, ketamine, lidocaine, and dexmedetomidine) in patients undergoing coronary artery bypass grafting. METHODS: This retrospective, multicenter observational study was conducted across private and public teaching sectors. We studied patients managed by a fast-track protocol or via usual care according to clinician preference. The primary outcome was the total mechanical ventilation time in hours adjusted for hospital, body mass index, category of surgical urgency, cardiopulmonary bypass time and EuroSCORE II. Secondary outcomes included successful extubation within four postoperative hours, postoperative pain scores, postoperative opioid requirements, and the development of postoperative complications. RESULTS: We included 87 patients in the fast-track group and 88 patients in the usual care group. Fast-track patients had a 35% reduction in total ventilation hours compared with usual care patients (p = 0.007). Thirty-five (40.2%) fast-track patients were extubated within four hours compared to 10 (11.4%) usual-care patients (odds ratio: 5.2 [95% CI: 2.39-11.08; p < 0.001]). Over 24 h, fast-track patients had less severe pain (p < 0.001) and required less intravenous morphine equivalent (22.00 mg [15.75:32.50] vs. 38.75 mg [20.50:81.75]; p < 0.001). There were no significant differences observed in postoperative complications or length of hospital stay between the groups. CONCLUSION: Implementing an FTCA protocol using methadone, dexmedetomidine, magnesium, ketamine, lignocaine, and remifentanil together with protocolized weaning from a mechanical ventilation protocol is associated with significantly reduced time to tracheal extubation, improved postoperative analgesia, and reduced opioid use without any adverse safety events. A prospective randomized trial is warranted to further investigate the combined effects of these medications in reducing complications and length of stay in FTCA. TRIALS REGISTRATION: The study protocol was registered in the Australian New Zealand Clinical Trials Registry ( https://www.anzctr.org.au/ACTRN12623000060640.aspx , retrospectively registered on 17/01/2023).

Modulation of habenular and nucleus accumbens functional connectivity by ketamine in major depression.

INTRODUCTION: Major depressive disorder (MDD) is associated with dysfunctional reward processing, which involves functional circuitry of the habenula (Hb) and nucleus accumbens (NAc). Since ketamine elicits rapid antidepressant and antianhedonic effects in MDD, this study sought to investigate how serial ketamine infusion (SKI) treatment modulates static and dynamic functional connectivity (FC) in Hb and NAc functional networks. METHODS: MDD participants (n = 58, mean age = 40.7 years, female = 28) received four ketamine infusions (0.5 mg/kg) 2-3 times weekly. Resting-state functional magnetic resonance imaging (fMRI) scans and clinical assessments were collected at baseline and 24 h post-SKI. Static FC (sFC) and dynamic FC variability (dFCv) were calculated from left and right Hb and NAc seeds to all other brain regions. Changes in FC pre-to-post SKI, and correlations with changes with mood and anhedonia were examined. Comparisons of FC between patients and healthy controls (HC) at baseline (n = 55, mean age = 32.6, female = 31), and between HC assessed twice (n = 16) were conducted as follow-up analyses. RESULTS: Following SKI, significant increases in left Hb-bilateral visual cortex FC, decreases in left Hb-left inferior parietal cortex FC, and decreases in left NAc-right cerebellum FC occurred. Decreased dFCv between left Hb and right precuneus and visual cortex, and decreased dFCv between right NAc and right visual cortex both significantly correlated with improvements in mood ratings. Decreased FC between left Hb and bilateral visual/parietal cortices as well as increased FC between left NAc and right visual/parietal cortices both significantly correlated with improvements in anhedonia. No differences were observed between HC at baseline or over time. CONCLUSION: Subanesthetic ketamine modulates functional pathways linking the Hb and NAc with visual, parietal, and cerebellar regions in MDD. Overlapping effects between Hb and NAc functional systems were associated with ketamine's therapeutic response.

Dexmedetomidine-ketamine combination versus fentanyl-midazolam for patient sedation during flexible bronchoscopy: a prospective, single-blind, randomized controlled trial.

BACKGROUND: Sedation during flexible bronchoscopy (FB) should maintain an adequate respiratory drive, ensure maximum comfort for the patient, and warrant that the objectives of the procedure are achieved. Nevertheless, the optimal sedation method for FB has yet to be established. This study aimed to compare the standard recommended combination of midazolam-fentanyl (MF) with that of dexmedetomidine-ketamine (DK) for patient sedation during FB. METHODS: Patients subjected to FB were randomly assigned to a DK (n = 25) and an MF group (n = 25). The primary outcome was the rate of critical desaturation events (arterial oxygen saturation < 80% with nasal oxygen supply 2 L/min). Secondary outcomes included sedation depth, hemodynamic complications, adverse events, and patient and bronchoscopist satisfaction. RESULTS: The incidence rates of critical desaturation events were similar between the two groups (DK: 12% vs. MF: 28%, p = 0.289). DK achieved deeper maximum sedation levels (higher Ramsay - lower Riker scale; p < 0.001) and was associated with longer recovery times (p < 0.001). Both groups had comparable rates of hemodynamic and other complications. Patient satisfaction was similar between the two groups, but bronchoscopist satisfaction was higher with the DK combination (p = 0.033). CONCLUSION: DK demonstrated a good safety profile in patients subjected to FB and achieved more profound sedation and better bronchoscopist satisfaction than the standard MF combination without increasing the rate of adverse events.