Effects of esketamine on postoperative negative emotions and early cognitive disorders in patients undergoing non-cardiac thoracic surgery: A randomized controlled trial

STUDY OBJECTIVE

To investigate whether a single dosage of esketamine injection in the anesthesia period could improve postoperative negative emotions and early cognitive function in patients undergoing non-cardiac thoracic surgery.

DESIGN

A prospective single center double blinded randomized placebo-controlled trial.

SETTING

Perioperative period; operating room, post anesthesia care unit and hospital ward.

PATIENTS

129 adult patients that underwent elective non-cardiac thoracic surgery under general anesthesia.

INTERVENTIONS

During the operation, pharmacologic prevention of postoperative negative emotion and early cognitive disorder with 0.2 mg/kg (Low esketamine group) and 0.5 mg/kg esketamine (High esketamine group) vs. placebo.

MEASUREMENTS

Emotion and early cognitive performance were assessed on the day before surgery (POD-1), postoperative day 1 (POD1) and day 3 (POD3) using HADS-A, HADS-D, Pain Visual Analogue Scale (VAS), Confusion Assessment Method (CAM), Mini-Mental State Examination (MMSE), and serum biomarkers (S100β, BDNF, IL-6, acetylcholine, and norepinephrine).

MAIN RESULTS

The high esketamine group showed significantly lower HADS-A and HADS-D scores than control group on POD1 and POD3. No significant differences were observed between the low esketamine group and the control group. The esketamine-treated groups showed lower pain VAS scores than the control group at 2 h and on the first day after operation. There were no significant differences among the three groups in CAM and MMSE scores. However, the high esketamine group had lower S100β and IL-6 levels, and higher BDNF levels postoperatively, while serum acetylcholine and norepinephrine were not significantly different.

CONCLUSIONS

A single intraoperative injection of 0.5 mg/kg esketamine can alleviate postoperative anxiety, depression, and pain to some extent. Although cognitive function behavioral evaluation did not show obvious benefits, it can also reduce the production of pro-inflammatory and brain injury-related factors while promoting the generation of brain-derived neurotrophic factor. Registration Trial registry: http://www.chictr.org.cn/; Identifier: ChiCTR2100047067.

Editorial: Novel Approaches to the Treatment of Suicidality and Depression in Youth

Suicide continues to be a major cause of mortality in adolescents with limited treatment options.1,2 Effective treatments, both therapy and medication, are available for treating depression, but even with the best combination, treatment remission rates are low.3 The most common approach to treating suicidality, which includes suicidal ideation and suicidal behavior, is to address concomitant depression. Ketamine and its enantiomers have shown rapid anti-suicidal effects in adults with MDD, and intranasal esketamine is approved for treating treatment-resistant depression (TRD) in adults.4,5 The effectiveness of ketamine for the treatment of depression frequently lags behind the treatment of suicidality. There are also many methodological differences and barriers to assessing the effectiveness of short-term treatments. These include measurement of change over short time frames, measurement of suicidality, and so forth. Finally, the use of novel short-term treatments in treating chronic depression and suicidality in real-world situations is unclear.

A comparative analysis of opioid-free and opioid-sparing anaesthesia techniques for laparoscopic ovariectomy in healthy dogs

OBJECTIVE

To compare the perioperative analgesic effects of an opioid-free (OFA) and an opioid-sparing (OSA) anaesthetic protocol in dogs undergoing laparoscopic ovariectomy.

STUDY DESIGN

Prospective, randomized, blinded, clinical trial.

ANIMALS

A group of 28 client-owned dogs.

METHODS

Dogs were allocated to one of two groups. The OFA group was administered intramuscular (IM) dexmedetomidine 5 μg kg-1 and ketamine 1 mg kg-1, followed by two intraoperative constant rate infusions (CRIs) of dexmedetomidine (3 μg kg-1 hour-1) and lidocaine (1 mg kg-1 loading dose, 2 mg kg-1 hour-1). The OSA group was administered IM dexmedetomidine 5 μg kg-1, ketamine 1 mg kg-1 and methadone 0.2 mg kg-1, followed by two intraoperative saline CRIs. In both groups, anaesthesia was induced with intravenous (IV) propofol 2 mg kg-1 and diazepam 0.2 mg kg-1 and maintained with isoflurane. Rescue dexmedetomidine (0.5 μg kg-1) was administered IV if there was a 20% increase in cardiovascular variables compared with pre-stimulation values. Ketorolac (0.5 mg kg-1) was administered IV when the surgery ended. Postoperative analgesia was evaluated using the Short Form-Glasgow Composite Measure Pain Scale and methadone (0.2 mg kg-1) was administered IM if the pain score was ≥ 6/24. Statistical analysis included mixed analysis of variance, Chi-square test and Mann-Whitney U test.

RESULTS

There were no significant differences in the intraoperative monitored variables between groups. The OFA group showed a significantly lower intraoperative rescue analgesia requirement (p = 0.016) and lower postoperative pain scores at 3 (p =0.001) and 6 (p < 0.001) hours. No dogs were administered rescue methadone postoperatively.

CONCLUSIONS AND CLINICAL RELEVANCE

Although both groups achieved acceptable postoperative pain scores with no need for further intervention, the analgesic efficacy of the OFA protocol was significantly superior to that of the OSA protocol presented and was associated with a lower intraoperative rescue analgesia requirement and early postoperative pain scores.

GM-1020: a novel, orally bioavailable NMDA receptor antagonist with rapid and robust antidepressant-like effects at well-tolerated doses in rodents

The NMDA receptor (NMDAR) antagonist ketamine has shown great potential as a rapid-acting antidepressant; however, its use is limited by poor oral bioavailability and a side effect profile that necessitates in-clinic dosing. GM-1020 is a novel NMDAR antagonist that was developed to address these limitations of ketamine as a treatment for depression. Here, we present the preclinical characterization of GM-1020 alongside ketamine, for comparison. In vitro, we profiled GM-1020 for binding to NMDAR and functional inhibition using patch-clamp electrophysiology. In vivo, GM-1020 was assessed for antidepressant-like efficacy using the Forced Swim Test (FST) and Chronic Mild Stress (CMS), while motor side effects were assessed in spontaneous locomotor activity and on the rotarod. The pharmacokinetic properties of GM-1020 were profiled across multiple preclinical species. Electroencephalography (EEG) was performed to determine indirect target engagement and provide a potentially translational biomarker. These results demonstrate that GM-1020 is an orally bioavailable NMDAR antagonist with antidepressant-like efficacy at exposures that do not produce unwanted motor effects.

Effect of Repeated Intravenous Esketamine on Adolescents With Major Depressive Disorder and Suicidal Ideation: A Randomized Active-Placebo-Controlled Trial

OBJECTIVE

Suicide is a major cause of death in adolescents with limited treatment options. Ketamine and its enantiomers have shown rapid anti-suicidal effects in adults with major depressive disorder (MDD), but their efficacy in adolescents is unknown. We conducted an active, placebo-controlled trial to determine the safety and efficacy of intravenous esketamine in this population.

METHOD

A total of 54 adolescents (aged 13-18 years) with MDD and suicidal ideation were included from an inpatient setting and randomly assigned (1:1) to receive 3 infusions of esketamine (0.25 mg/kg) or midazolam (0.02mg/kg) over 5 days, with routine inpatient care and treatment. Changes from baseline to 24 hours after the final infusion (day 6) in the scores of the Columbia Suicide Severity Rating Scale (C-SSRS) Ideation and Intensity (primary outcome) and the Montgomery-Åsberg Depression Rating Scale (MADRS, key secondary outcome) were analyzed using linear mixed models. In addition, the 4-week clinical treatment response was a key secondary outcome.

RESULTS

The mean changes in C-SSRS Ideation and Intensity scores from baseline to day 6 were significantly greater in the esketamine group than in the midazolam group (Ideation, -2.6 [SD = 2.0] vs -1.7 [SD = 2.2], p = .007; Intensity, -10.6 [SD = 8.4] vs -5.0 [SD = 7.4], p = .002), and the changes in MADRS scores from baseline to day 6 were significantly greater in the esketamine group than in the midazolam group (-15.3 [SD = 11.2] vs -8.8 [SD = 9.4], p = .004). The rates of antisuicidal and antidepressant responses at 4 weeks posttreatment were 69.2% and 61.5% after esketamine, and were 52.5% and 52.5% after midazolam, respectively. The most common adverse events in the esketamine group were nausea, dissociation, dry mouth, sedation, headache, and dizziness.

CONCLUSION

These preliminary findings indicate that 3-dose intravenous esketamine, added to routine inpatient care and treatment, was an effective and well-tolerated therapy for treating adolescents with MDD and suicidal ideation.

CLINICAL TRIAL REGISTRATION INFORMATION

A study to evaluate the efficacy and safety of Esketamine combined with oral antidepressants in the treatment of major depressive disorder with suicidal ideation; http://www.chictr.org.cn; ChiCTR2000041232.

DIVERSITY & INCLUSION STATEMENT

We worked to ensure that the study questionnaires were prepared in an inclusive way. The author list of this paper includes contributors from the location and/or community where the research was conducted who participated in the data collection, design, analysis, and/or interpretation of the work. We actively worked to promote sex and gender balance in our author group.

Effects of a single subanesthetic dose of esketamine on postoperative subthreshold depressive symptoms in patients undergoing unilateral modified radical mastectomy: a randomised, controlled, double-blind trial

BACKGROUND

Breast cancer is the most common malignant tumor in females worldwide. During disease development, breast cancer patients suffer anxious and depressed, which may lead to worse quality of life or even higher mortality. Esketamine has been regarded as an antidepressant in breast cancer patients with mild or moderate depression. Here, we wonder whether the administration of esketamine could reduce the postoperative depressive symptom score of breast cancer patients who have no preoperative depression.

METHODS

A total of 64 patients treated with unilateral modified radical mastectomy were randomly divided into an experimental group (esketamine group, Group E) and a control group (Group C), with 32 cases in each one. After anesthesia induction, Group C received 0.2 ml/kg of normal saline intravenously and Group E was administered 0.2 mg/kg intravenous esketamine. The primary outcome was the Patient Health Questionnaire-9 (PHQ-9) scores. The secondary outcomes included the Visual Analogue Scale (VAS) scores for pain, inflammatory markers, perioperative-related indicators, and the incidence of postoperative delirium, nausea and vomiting.

RESULTS

The PHQ-9 score on postoperative day (POD) 1 in Group E declined from the preoperative level, while the score in Group C was higher than before, and the former was far lower than the latter (P = 0.047). There is no statistically significant difference in PHQ-9 scores between Group E and Group C on POD 3, 7, and 30. Moreover, the postoperative leukocyte level of Group E was higher than that of Group C, and the difference was statistically significant (P = 0.030).

CONCLUSIONS

A single subanesthetic dose of esketamine can result in lower postoperative score on subthreshold depressive symptoms compared to the Group C on POD 1, without increasing the occurrence of postoperative adverse reactions.

TRIAL REGISTRATION

Registration number: Chinese Clinical Trial Registry ChiCTR2200057028. Date of registration: 26/02/2022.

The Effect of Preprocedural Low-Dose Ketamine for Pain and Anxiety in Patients during Thoracic Epidural Catheterization

Background and Objectives: Thoracic epidural catheterization (TEC) can be both uncomfortable and fearful for patients when performed awake with the thought that the procedure may be painful. The aim of this study was to assess the effect of low-dose intravenous ketamine administration on pain and anxiety during the TEC procedure. Materials and Methods: Sixty patients were randomly divided into two groups to receive intravenous (IV) placebo (Group P) and IV low-dose (0.15 mg/kg) ketamine (LDK) (Group K) 3 min before the procedure in a double-blind manner. A visual analog scale (VAS) was used to measure anxiety (VAS-A) and pain (VAS-P) scores. Vital parameters were monitored before premedication (T1), 20 min after premedication (T2), during skin anesthesia (T3), during TEC (T4), and 5 min after TEC (T5). VAS-A values were recorded at T1, T3, T4, and T5 periods, and VAS-P levels were noted at T3, T4, and T5 periods. Results: During TEC (T4), both VAS-P and VAS-A were significantly lower in Group K (p < 0.001). The mean VAS-A value was 10.6 mm lower, and the mean VAS-P value was 9 mm lower in Group K than in Group P at the T4 time point. Additionally, the mean VAS-P value was 7.7 mm lower in Group K compared to Group P at the T3 time point (p < 0.001). Both groups showed a statistically significant difference in VAS-A measurements when compared at their respective time points (p < 0.001). However, only Group P demonstrated a statistically significant difference in VAS-P measurements (p < 0.001). VAS-P values remained stable in Group K. The number of patients who did not recall the procedure was significantly higher in Group K (p < 0.001). Furthermore, the number of patients who would consent to the same procedure in the future was significantly higher in Group K (p = 0.007). Conclusions: A preprocedural LDK (0.15 mg/kg) can effectively prevent anxiety and pain experienced by patients during the TEC procedure. Administration of LDK may provide a more comfortable procedure process without causing ketamine-induced side effects (hemodynamic, respiratory, and psychological).

Effect of S-Ketamine on Postoperative Nausea and Vomiting in Patients Undergoing Video-Assisted Thoracic Surgery: A Randomized Controlled Trial

Purpose

Postoperative nausea and vomiting (PONV) frequently occur in patients after surgery. In this study, the authors investigated whether perioperative S-ketamine infusion could decrease the incidence of PONV in patients undergoing video-assisted thoracoscopic surgery (VATS) lobectomy.

Patients and Methods

This prospective, randomized, double-blinded, controlled study was conducted a total of 420 patients from September 2021 to May 2023 at Xuzhou Central Hospital in China, who underwent elective VATS lobectomy under general anesthesia with tracheal intubation. The patients were randomly assigned to either the S-ketamine group or the control group. The S-ketamine group received a bolus injection of 0.5 mg/kg S-ketamine and an intraoperative continuous infusion of S-ketamine at a rate of 0.25 mg/kg/h. The control group received an equivalent volume of saline. All patients were equipped with patient-controlled intravenous analgesia (PCIA), with a continuous infusion rate of 0.03 mg/kg/h S-ketamine in the S-ketamine group or 0.03 μg/kg/h sufentanil in the control group. The primary outcome was the incidence of PONV. Secondary outcomes included perioperative opioid consumption, hemodynamics, postoperative pain, and adverse events.

Results

The incidence of PONV in the S-ketamine group (9.7%) was significantly lower than in the control group (30.5%). Analysis of perioperative opioid usage revealed that remifentanil usage was 40.0% lower in the S-ketamine group compared to the control group (1414.8 μg vs 2358.2 μg), while sufentanil consumption was 75.2% lower (33.1 μg vs 133.6 μg). The S-ketamine group demonstrated better maintenance of hemodynamic stability. Additionally, the visual analogue scale (VAS) scores on postoperative day 1 (POD-1) and postoperative day 3 (POD-3) were significantly lower in the S-ketamine group. Finally, no statistically significant difference in other postoperative adverse reactions was observed between the two groups.

Conclusion

The results of this trial indicate that perioperative S-ketamine infusion can effectively reduce the incidence of PONV in patients undergoing VATS lobectomy.

Enhancing Cognitive Functions and Neuronal Growth through NPY1R Agonist and Ketamine Co-Administration: Evidence for NPY1R-TrkB Heteroreceptor Complexes in Rats

This study investigates the combined effects of the neuropeptide Y Y1 receptor (NPY1R) agonist [Leu31-Pro34]NPY at a dose of 132 µg and Ketamine at 10 mg/Kg on cognitive functions and neuronal proliferation, against a backdrop where neurodegenerative diseases present an escalating challenge to global health systems. Utilizing male Sprague-Dawley rats in a physiological model, this research employed a single-dose administration of these compounds and assessed their impact 24 h after treatment on object-in-place memory tasks, alongside cellular proliferation within the dorsal hippocampus dentate gyrus. Methods such as the in situ proximity ligation assay and immunohistochemistry for proliferating a cell nuclear antigen (PCNA) and doublecortin (DCX) were utilized. The results demonstrated that co-administration significantly enhanced memory consolidation and increased neuronal proliferation, specifically neuroblasts, without affecting quiescent neural progenitors and astrocytes. These effects were mediated by the potential formation of NPY1R-TrkB heteroreceptor complexes, as suggested by receptor co-localization studies, although further investigation is required to conclusively prove this interaction. The findings also highlighted the pivotal role of brain-derived neurotrophic factor (BDNF) in mediating these effects. In conclusion, this study presents a promising avenue for enhancing cognitive functions and neuronal proliferation through the synergistic action of the NPY1R agonist and Ketamine, potentially via NPY1R-TrkB heteroreceptor complex formation, offering new insights into therapeutic strategies for neurodegenerative diseases.

Effects of Mild Closed-Head Injury and Subanesthetic Ketamine Infusion on Microglia, Axonal Injury, and Synaptic Density in Sprague-Dawley Rats

Mild traumatic brain injury (mTBI) affects millions of people in the U.S. Approximately 20-30% of those individuals develop adverse symptoms lasting at least 3 months. In a rat mTBI study, the closed-head impact model of engineered rotational acceleration (CHIMERA) produced significant axonal injury in the optic tract (OT), indicating white-matter damage. Because retinal ganglion cells project to the lateral geniculate nucleus (LGN) in the thalamus through the OT, we hypothesized that synaptic density may be reduced in the LGN of rats following CHIMERA injury. A modified SEQUIN (synaptic evaluation and quantification by imaging nanostructure) method, combined with immunofluorescent double-labeling of pre-synaptic (synapsin) and post-synaptic (PSD-95) markers, was used to quantify synaptic density in the LGN. Microglial activation at the CHIMERA injury site was determined using Iba-1 immunohistochemistry. Additionally, the effects of ketamine, a potential neuroprotective drug, were evaluated in CHIMERA-induced mTBI. A single-session repetitive (ssr-) CHIMERA (3 impacts, 1.5 joule/impact) produced mild effects on microglial activation at the injury site, which was significantly enhanced by post-injury intravenous ketamine (10 mg/kg) infusion. However, ssr-CHIMERA did not alter synaptic density in the LGN, although ketamine produced a trend of reduction in synaptic density at post-injury day 4. Further research is necessary to characterize the effects of ssr-CHIMERA and subanesthetic doses of intravenous ketamine on different brain regions and multiple time points post-injury. The current study demonstrates the utility of the ssr-CHIMERA as a rodent model of mTBI, which researchers can use to identify biological mechanisms of mTBI and to develop improved treatment strategies for individuals suffering from head trauma.

Functional connectivity of the amygdala subregions and the antidepressant effects of repeated ketamine infusions in major depressive disorder

BACKGROUND

Amygdala subregion-based network dysfunction has been determined to be centrally implicated in major depressive disorder (MDD). Little is known about whether ketamine modulates amygdala subarea-related networks. We aimed to investigate the relationships between changes in the resting-state functional connectivity (RSFC) of amygdala subregions and ketamine treatment and to identify important neuroimaging predictors of treatment outcomes.

METHODS

Thirty-nine MDD patients received six doses of ketamine (0.5 mg/kg). Depressive symptoms were assessed, and magnetic resonance imaging (MRI) scans were performed before and after treatment. Forty-five healthy controls underwent one MRI scan. Seed-to-voxel RSFC analyses were performed on the amygdala subregions, including the centromedial amygdala (CMA), laterobasal amygdala (LBA), and superficial amygdala subregions.

RESULTS

Abnormal RSFC between the left LBA and the left precuneus in MDD patients is related to the therapeutic efficacy of ketamine. There were significant differences in changes in bilateral CMA RSFC with the left orbital part superior frontal gyrus and in changes in the left LBA with the right middle frontal gyrus between responders and nonresponders following ketamine treatment. Moreover, there was a difference in the RSFC of left LBA and the right superior temporal gyrus/middle temporal gyrus (STG/MTG) between responders and nonresponders at baseline, which could predict the antidepressant effect of ketamine on Day 13.

CONCLUSIONS

The mechanism by which ketamine improves depressive symptoms may be related to its regulation of RSFC in the amygdala subregion. The RSFC between the left LBA and right STG/MTG may predict the response to the antidepressant effect of ketamine.

Challenges of acute pain management in older patients

Adequate management of acute pain in the older population is crucial. However, it is inherently complex because of multiple physiological changes that significantly impact both the pharmacokinetics and pharmacodynamics of medications. Current guidelines promote paracetamol as the first-line analgesic for acute pain in older adults, whereas opioids are advised cautiously for moderate to severe acute pain. However, opioids come with a significant array of side effects, which can be more pronounced in older individuals. Ketamine administered via intranasal (IN) and nebulised inhalation in the emergency department for managing acute pain in older patients shows promising potential for improving pain management and reducing opioid reliance Kampan, Thong-on, Sri-on (2024, Age Ageing, 53, afad255). Nebulised ketamine appears superior in terms of adverse event incidence. However, the adoption of IN or nebulised ketamine in older adult acute pain management remains unclear because of the lack of definitive conclusions and clear guidelines. Nevertheless, these modalities can be valuable options for patients where opioid analgesics are contraindicated or when intravenous morphine titration is impractical or contraindicated. Here, we review these concepts, the latest evidence and propose avenues for research.

Acute Dissociation and Ketamine's Antidepressant and Anti-Suicidal Ideation Effects in a Midazolam-Controlled Trial

OBJECTIVE

We sought to explore relationships of acute dissociative effects of intravenous ketamine with change in depression and suicidal ideation and with plasma metabolite levels in a randomized, midazolam-controlled trial.

METHODS

Data from a completed trial in suicidal, depressed participants (n = 40) randomly assigned to ketamine was used to examine relationships between ketamine treatment-emergent dissociative and psychotomimetic symptoms with pre/post-infusion changes in suicidal ideation and depression severity. Nonparametric correlational statistics were used. These methods were also used to explore associations between dissociative or psychotomimetic symptoms and blood levels of ketamine and metabolites in a subset of participants (n = 28) who provided blood samples immediately post-infusion.

RESULTS

Neither acute dissociative nor psychotomimetic effects of ketamine were associated with changes in suicidal ideation or depressive symptoms from pre- to post-infusion. Norketamine had a trend-level, moderate inverse correlation with dissociative symptoms on Day 1 post-injection (P  = .064; P =.013 removing 1 outlier). Dehydronorketamine correlated with Clinician-Administered Dissociative States Scale scores at 40 minutes (P = .034), 230 minutes (P = .014), and Day 1 (P = .012).

CONCLUSION

We did not find evidence that ketamine's acute, transient dissociative, or psychotomimetic effects are associated with its antidepressant or anti-suicidal ideation actions. The correlation of higher plasma norketamine with lower dissociative symptoms on Day 1 post-treatment suggests dissociation may be more an effect of the parent drug.

Development of a novel rodent rapid serial visual presentation task reveals dissociable effects of stimulant versus nonstimulant treatments on attentional processes

The rapid serial visual presentation (RSVP) task and continuous performance tasks (CPT) are used to assess attentional impairments in patients with psychiatric and neurological conditions. This study developed a novel touchscreen task for rats based on the structure of a human RSVP task and used pharmacological manipulations to investigate their effects on different performance measures. Normal animals were trained to respond to a target image and withhold responding to distractor images presented within a continuous sequence. In a second version of the task, a false-alarm image was included, so performance could be assessed relative to two types of nontarget distractors. The effects of acute administration of stimulant and nonstimulant treatments for ADHD (amphetamine and atomoxetine) were tested in both tasks. Methylphenidate, ketamine, and nicotine were tested in the first task only. Amphetamine made animals more impulsive and decreased overall accuracy but increased accuracy when the target was presented early in the image sequence. Atomoxetine improved accuracy overall with a specific reduction in false-alarm responses and a shift in the attentional curve reflecting improved accuracy for targets later in the image sequence. However, atomoxetine also slowed responding and increased omissions. Ketamine, nicotine, and methylphenidate had no specific effects at the doses tested. These results suggest that stimulant versus nonstimulant treatments have different effects on attention and impulsive behaviour in this rat version of an RSVP task. These results also suggest that RSVP-like tasks have the potential to be used to study attention in rodents.

Role of Flt3l and Rps15 in ketamine anesthesia

Ketamine is the only intravenous narcotic that has sedative, analgesic, and anesthetic effects. However, the role of Flt3l and ribosomal protein S15 (Rps15) in ketamine anesthesia remains unclear. GSE26364 and GSE93041 were downloaded from gene expression omnibus. Multiple datasets were merged and batched. Differentially expressed genes (DEGs) were screened and weighted gene co-expression network analysis was performed. Construction and analysis of protein-protein interaction network. Gene ontology (GO) and Kyoto Encyclopedia of Gene and Genome were performed. A heat map of gene expression was drawn. TargetScan was used to screen miRNAs regulating DEGs. 882 DEGs were identified. According to the GO analysis, these DEGs were mainly enriched in cell differentiation, extracellular region, and cytoplasm. The Kyoto Encyclopedia of Gene and Genome analysis revealed enrichment in pathways such as the PPAR signaling pathway, TNF signaling pathway, Hippo signaling pathway, and IL-17 signaling pathway. In the Metascape enrichment analysis, GO enrichment categories included leukocyte differentiation, negative regulation of CREB transcription factor activity, and positive regulation of cell cycle. The protein-protein interaction network showed 10 core genes (Rpl7, Rpl18, Rps15, Rpl7l1, Flt3l, Rps16, Eprs, Rps19, Rps28, Rplp2).Gene expression heatmap showed that core genes (Rplp2, Flt3l, Rps15) were highly expressed in samples treated with ketamine anesthesia. Flt3l and Rps15 are highly expressed during ketamine anesthesia, and may be molecular targets.

New pharmacotherapies to tackle the unmet needs in bipolar disorder: a focus on acute suicidality

INTRODUCTION

Suicidal behavior is relatively frequent in patients with bipolar disorder (BD) and constitutes their most frequent cause of death. Suicide rates remain high in patients with BD despite adherence to guidelines recommending lithium as first line, and/or antidepressants, antipsychotics, psychotherapy, psychosocial interventions, and electroconvulsive therapy. Hence the need to identify more effective and rapid anti-suicide interventions.

AREAS COVERED

To tackle the unmet needs of pharmacotherapy, we investigated the PubMed database on 24-25 January 2024 using strategies like ('acute suicid*'[ti] OR 'suicide crisis syndrome' OR 'acute suicidal affective disturbance') AND (lithium[ti] OR clozapine[ti]), which obtained 3 results, and ('acute suicid*'[ti] OR 'suicide crisis syndrome' OR 'acute suicidal affective disturbance') AND (ketamine[ti] OR esketamine[ti] OR NMDA[ti] OR glutamat*[ti]), which yielded 14 results. We explored glutamatergic abnormalities in BD and suicide and found alterations in both. The noncompetitive NMDS antagonist ketamine and its S-enantiomer esketamine reportedly decrease acute suicidality.

EXPERT OPINION

Intranasal esketamine or subcutaneous ketamine, single-bolus or intravenous, and possibly other glutamate receptor modulators may improve suicidal behavior in patients with unipolar and bipolar depression. This may be achieved through prompt remodulation of glutamate activity. The correct use of glutamatergic modulators could reduce acute suicidality and mortality in patients with BD.

The Application Value of Esketamine and Dexmedetomidine in Preventing Postoperative Delirium and Hyperalgesia in Elderly Patients with Thoracic Anesthesia

Objective

Our aim was to evauate the application value of esesketamine and dexmedetomidine in preventing postoperative hyperalgesia in elderly patients who received thoracic anesthesia.

Methods

A total of 94 elderly patients who underwent thoracic anesthesia in Sanmen People's Hospital from January 2021 to October 2022 were selected and divided into a dexmedetomidine group (n = 47) and an esketamine group (n = 47) by the random number table method. All patients were continuously received intravenous (IV) remifentanil. In the dexmedetomidine group, dexmedetomidine 0.7 μg/kg was administered IV, followed by 0.2 to 0.5 μg/kg/h to maintain anesthesia, while in the esketamine group, esketamine 0.5 mg/kg was given IV 20 min after induction of anesthesia was completed.

Results

Visual analogue scale (VAS) scores in the esketamine group were lower than in the dexmedetomidine group at 1, 6, 12 and 24 h postoperatively (P < .05), and Ramsay sedation scores were not statistically different from those in the dexmedetomidine group (P > .05). At 3 d postoperatively, the Mini-Mental State Examination (MMSE) scores in the dexmedetomidine group were lower than 1 d preoperatively; at 5 d postoperatively, the negative mood and Pittsburgh Sleep Quality Index (PSQI) scores were significantly higher in both groups than 1 d preoperatively; at 14 d postoperatively, the PSQI scores were higher in both groups than 1 d preoperatively, and there was no statistical difference between the negative mood scores at 1 d before surgery (P > .05). At 5 d postoperatively in the esketamine group, the negative mood scores were lower than in the dexmedetomidine group at 5 d postoperatively and the PSQI scores at 5 and 14 d postoperatively were lower than in the dexmedetomidine group (P < .05).

Conclusion

Both esketamine and dexmedetomidine can be used to prevent postoperative delirium and nociceptive hypersensitivity after anesthesia in elderly patients with thoracic surgery. However, esketamine is superior to dexmedetomidine in analgesic effect, improvement of negative mood and sleep and stabilization of intraoperative hemodynamics, leading to better effect in preventing delirium and hyperalgesia after anesthesia.

Continuous ketamine infusion for the management of opioid-induced hyperalgesia following amputation

We discuss the use of an inpatient multi-day continuous intravenous ketamine infusion for the treatment of opioid-induced hyperalgesia (OIH) and high fentanyl requirements in the case of a patient with a background of fibromyalgia/central sensitisation syndrome who underwent a complicated post-operative course following a right below-knee amputation for high-grade myxoid fibrosarcoma. The patient was successfully tapered off a total fentanyl patch dose of 162 mcg/hour every 72 hours (morphine equivalent dose of 389 mg/day) to short-acting hydromorphone 2 mg orally two times per day as needed (equivalent of 8 mg morphine sustained-release twice per day) during a 2-week admission with only mild withdrawal symptoms. We discuss the pharmacology of ketamine and its possible application in the treatment of OIH.

Effects of adding low-dose esketamine to sufentanil and propofol sedation during cervical conization: a single-centre, randomized controlled trial

BACKGROUND

Cervical conization is a brief but painful procedure that can be performed under sufficient sedation with propofol and opioids. However, this sedation approach comes with a high risk of sedation-related adverse events (SRAEs). Esketamine, an N-methyl-d-aspartate (NMDA) receptor antagonist, causes less cardiorespiratory depression than opioids. The aim of this study was to assess the efficacy and safety of adding a low dose of esketamine to propofol and sufentanil sedation as an opioid-reduced regimen.

METHODS

A total of 122 consecutive patients with ASA I-II, body mass index < 30, and STOP-BANG score < 3 who underwent cervical conization were enrolled and randomly divided into Group S and Group ES. Using a closed-loop target-controlled infusion (TCI) pump with a target bispectral index (BIS) value of 60 ± 5, patients in Group S were sedated with 0.2 mcg·kg-1 sufentanil and propofol, while patients in Group ES were sedated with 0.15 mg·kg-1 esketamine, 0.1 mcg·kg-1 sufentanil and propofol. The primary outcome was the incidence and severity of SRAEs, while the secondary outcomes included effectiveness of sedation, awakening time, psychotomimetic side effects, postoperative pain, postoperative nausea and vomiting, and patient and gynaecologist satisfaction.

RESULTS

Data from 120 patients were analysed. The incidence of composite SRAEs was significantly higher in Group S than in Group ES (85.0% vs. 56.7%, P < 0.05). Furthermore, the severity of SRAEs was higher in Group S than in Group ES (P < 0.001). There were no significant differences in the effectiveness of sedation, awakening time, psychotomimetic side effects, postoperative pain, postoperative nausea and vomiting, or patient and gynaecologist satisfaction between the two groups.

CONCLUSION

Adding low-dose esketamine to propofol and sufentanil sedation reduces the incidence and severity of SRAEs in patients undergoing cervical conization, with equal sedation efficacy, recovery quality, and no additional psychomimetic side effects.

TRIAL REGISTRATION

ChiCTR2000040457 , 28/11/2020.

Esketamine Nasal Spray versus Quetiapine for Treatment-Resistant Depression

BACKGROUND

In treatment-resistant depression, commonly defined as a lack of response to two or more consecutive treatments during the current depressive episode, the percentage of patients with remission is low and the percentage with relapse is high. The efficacy and safety of esketamine nasal spray as compared with extended-release quetiapine augmentation therapy, both in combination with ongoing treatment with a selective serotonin reuptake inhibitor (SSRI) or a serotonin-norepinephrine reuptake inhibitor (SNRI), in patients with treatment-resistant depression are unknown.

METHODS

In an open-label, single-blind (with raters unaware of group assignments), multicenter, phase 3b, randomized, active-controlled trial, we assigned patients, in a 1:1 ratio, to receive flexible doses (according to the summary of product characteristics) of esketamine nasal spray (esketamine group) or extended-release quetiapine (quetiapine group), both in combination with an SSRI or SNRI. The primary end point was remission, defined as a score of 10 or less on the Montgomery-Åsberg Depression Rating Scale (MADRS), at week 8 (scores range from 0 to 60, with higher scores indicating more severe depression). The key secondary end point was no relapse through week 32 after remission at week 8. All patients were included in the analysis; patients who discontinued the trial treatment were considered as having had an unfavorable outcome (i.e., they were grouped with patients who did not have remission or who had a relapse). Analyses of the primary and key secondary end points were adjusted for age and number of treatment failures.

RESULTS

Overall, 336 patients were assigned to the esketamine group and 340 to the quetiapine group. More patients in the esketamine group than in the quetiapine group had remission at week 8 (91 of 336 patients [27.1%] vs. 60 of 340 patients [17.6%]; P = 0.003) and had no relapse through week 32 after remission at week 8 (73 of 336 patients [21.7%] vs. 48 of 340 patients [14.1%]). Over 32 weeks of follow-up, the percentage of patients with remission, the percentage of patients with a treatment response, and the change in the MADRS score from baseline favored esketamine nasal spray. The adverse events were consistent with the established safety profiles of the trial treatments.

CONCLUSIONS

In patients with treatment-resistant depression, esketamine nasal spray plus an SSRI or SNRI was superior to extended-release quetiapine plus an SSRI or SNRI with respect to remission at week 8. (Funded by Janssen EMEA; ESCAPE-TRD ClinicalTrials.gov number, NCT04338321.).

Sustained antidepressant effect of ketamine through NMDAR trapping in the LHb

Ketamine, an N-methyl-D-aspartate receptor (NMDAR) antagonist1, has revolutionized the treatment of depression because of its potent, rapid and sustained antidepressant effects2-4. Although the elimination half-life of ketamine is only 13 min in mice5, its antidepressant activities can last for at least 24 h6-9. This large discrepancy poses an interesting basic biological question and has strong clinical implications. Here we demonstrate that after a single systemic injection, ketamine continues to suppress burst firing and block NMDARs in the lateral habenula (LHb) for up to 24 h. This long inhibition of NMDARs is not due to endocytosis but depends on the use-dependent trapping of ketamine in NMDARs. The rate of untrapping is regulated by neural activity. Harnessing the dynamic equilibrium of ketamine-NMDAR interactions by activating the LHb and opening local NMDARs at different plasma ketamine concentrations, we were able to either shorten or prolong the antidepressant effects of ketamine in vivo. These results provide new insights into the causal mechanisms of the sustained antidepressant effects of ketamine. The ability to modulate the duration of ketamine action based on the biophysical properties of ketamine-NMDAR interactions opens up new opportunities for the therapeutic use of ketamine.

Adverse drug effects as a deterrent against willingness to use in the future among nightclub/festival attendees

INTRODUCTION

It is largely unknown whether adverse effects experienced from recreational drug use affect willingness to use again. This study determined whether adverse effects from select party drugs affect reported willingness to use again in the next month among a high-risk population-people who attend electronic dance music parties at nightclubs or dance festivals.

METHODS

Adults (age ≥ 18) entering nightclubs/festivals were surveyed in New York City in 2018-2022 (n = 2981). Participants were asked about past-month use of common party drugs (cocaine, ecstasy, lysergic acid diethylamide [LSD] and ketamine), whether they had experienced a harmful or very unpleasant effect after use in the past 30 days, and whether they intend to use again in the next 30 days if offered by a friend. The relationship between having experienced an adverse outcome and willingness to use again was examined in a bivariable and multivariable manner.

RESULTS

Experiencing an adverse effect after past-month cocaine (adjusted prevalence ratio [aPR] = 0.58, 95% confidence interval [CI] 0.35-0.95) or ecstasy use (aPR = 0.45, 95% CI 0.25-0.80) was associated with lower risk for willingness to use again. Adverse effects related to LSD use were related to lower risk of being willing to use again in the bivariable model, but in multivariable models, risk was not attenuated for willingness to use LSD or ketamine again.

DISCUSSION AND CONCLUSIONS

Personally experienced adverse effects can deter willingness to use certain party drugs again in this high-risk population. Interventions targeting cessation of recreational party drug use can likely benefit from focusing on deleterious effects of use that have been experienced.

Effect of intravenous induction with different doses of Esketamine combined with propofol and sufentanil on intraocular pressure among pediatric strabismus surgery: a randomized clinical trial

BACKGROUND

It is well-established that maintaining stable intraocular pressure (IOP) within the normal range during ophthalmic surgery is important. Esketamine is a commonly used drug in pediatric general anesthesia due to its good analgesic and sedative effects. However, its application in ophthalmic surgery is limited because it can increase IOP. The effect of esketamine combined with other common anesthetics on IOP has been underinvestigated. This study aimed to investigate the effect of different doses of esketamine combined with propofol and sufentanil on IOP during intravenous induction of general anesthesia for pediatric strabismus surgery.

METHODS

A total of 181 children with strabismus undergoing unilateral eye surgery under general anesthesia were recruited. Intravenous induction included the use of sufentanil 0.1 µg/kg, propofol 3 mg/kg, and esketamine. Base on the dosage of esketamine, the patients were randomly allocated into three groups: esketamine low (EL) group with 0.25 mg/kg (n = 62), esketamine high (EH) group with 0.5 mg/kg (n = 60), and normal saline (NS) group (n = 59). Hemodynamic parameters, respiratory parameters, and IOP of the non-surgical eye were recorded and compared among the three groups at different time points: before induction (T0), 1 min after induction but before laryngeal mask insertion (T1), immediately after laryngeal mask insertion (T2), and 2 min after laryngeal mask insertion (T3).

RESULTS

There were no significant differences in age, gender, body mass index (BMI), and respiratory parameters among the three groups at T0. The IOP at T1, T2, and T3 was lower than that at T0 in all three groups. The EH group (12.6 ± 1.6 mmHg) had a significantly higher IOP than the EL group (12.0 ± 1.6 mmHg) and the NS group (11.6 ± 1.7 mmHg) at T1. However, no difference was found between the EL and NS groups at any time point. Systolic blood pressure (SBP) and heart rate (HR) at T1, T2, and T3 were lower than at baseline, and SBP and HR were higher at T2 than at T1. Additionally, the EH group had a significantly higher HR at T1 than the other two groups. There was no significant difference in diastolic blood pressure (DBP) among the three groups at any time point.

CONCLUSION

Propofol combined with sufentanil significantly decreased IOP during the induction of general anesthesia. Although a dose of 0.5 mg/kg esketamine elevated IOP compared to the low-dose and control groups after induction, the IOP remained lower than baseline. 0.25 mg/kg esketamine combined with propofol and sufentanil had little effect on IOP. Therefore, we advocate that a maximum dose of 0.5 mg/kg esketamine combined with propofol and sufentanil will not elevate IOP compared to baseline in pediatric strabismus surgery.

TRIAL REGISTRATION

The registration number is ChiCTR2200066586 at Chictr.org.cn. Registry on 09/12/2022.

Effects of intra-operative administration of subanesthetic s-ketamine on emergence from sevoflurane anesthesia: a randomized double-blind placebo-controlled study

BACKGROUND

Ketamine is administered in the perioperative period for its benefits in analgesia, anti-agitation and anti-depression when administered at a small dose. However, it is not clear whether the intra-operative administration of ketamine would affect emergence under sevoflurane anesthesia. To investigate this effect, we designed this trial.

METHODS

In this randomized, double-blind, placebo-controlled study, we enrolled 44 female patients aged 18-60 who were scheduled to elective laparoscopic gynecological surgeries. All patients were randomly assigned to saline or s-ketamine group. In s-ketamine group, patients received 0.125 mg/kg s-ketamine 30 min after the start of surgery. In saline group, patients were administered the same volume of saline. Sevoflurane and remifentanil were used to maintain general anesthesia. The primary outcome was emergence time. We also assessed postoperative agitation, cognitive function, and delirium. In addition, we collected and analyzed prefrontal electroencephalogram (EEG) during and after general anesthesia.

RESULTS

There were no significant differences in emergence time between s-ketamine group and saline group (10.80 ± 3.77 min vs. 10.00 ± 2.78 min, P = 0.457). Neither postoperative agitation (4 [3, 4] vs. 4 [3, 4], P = 0.835) nor cognitive function (25.84 ± 2.69 vs. 25.55 ± 2.19, P = 0.412) differed between groups. No postoperative delirium was observed in either group. Subanesthetic s-ketamine resulted in active EEG with decreased power of slow (-0.35 ± 1.13 dB vs. -1.63 ± 1.03 dB, P = 0.003), delta (-0.22 ± 1.11 dB vs. -1.32 ± 1.09 dB, P = 0.011) and alpha (-0.31 ± 0.71 dB vs. -1.71 ± 1.34 dB, P = 0.0003) waves and increased power of beta-gamma bands (-0.30 ± 0.89 dB vs. 4.20 ± 2.08 dB, P < 0.0001) during sevoflurane anesthesia, as well as an increased alpha peak frequency (-0.16 ± 0.48 Hz vs. 0.31 ± 0.73 Hz, P = 0.026). EEG patterns did not differ during the recovery period after emergence between groups.

CONCLUSION

Ketamine administered during sevoflurane anesthesia had no apparent influence on emergence time in young and middle-aged female patients undergoing laparoscopic surgery. Subanesthetic s-ketamine induced an active prefrontal EEG pattern during sevoflurane anesthesia but did not raise neurological side effects after surgery.

TRIAL REGISTRATION

Chinese Clinical Trial Registry, ChiCTR2100046479 (date: 16/05/2021).

Ketamine versus ECT for Nonpsychotic Treatment-Resistant Major Depression

BACKGROUND

Electroconvulsive therapy (ECT) and subanesthetic intravenous ketamine are both currently used for treatment-resistant major depression, but the comparative effectiveness of the two treatments remains uncertain.

METHODS

We conducted an open-label, randomized, noninferiority trial involving patients referred to ECT clinics for treatment-resistant major depression. Patients with treatment-resistant major depression without psychosis were recruited and assigned in a 1:1 ratio to receive ketamine or ECT. During an initial 3-week treatment phase, patients received either ECT three times per week or ketamine (0.5 mg per kilogram of body weight over 40 minutes) twice per week. The primary outcome was a response to treatment (i.e., a decrease of ≥50% from baseline in the score on the 16-item Quick Inventory of Depressive Symptomatology-Self-Report; scores range from 0 to 27, with higher scores indicating greater depression). The noninferiority margin was -10 percentage points. Secondary outcomes included scores on memory tests and patient-reported quality of life. After the initial treatment phase, the patients who had a response were followed over a 6-month period.

RESULTS

A total of 403 patients underwent randomization at five clinical sites; 200 patients were assigned to the ketamine group and 203 to the ECT group. After 38 patients had withdrawn before initiation of the assigned treatment, ketamine was administered to 195 patients and ECT to 170 patients. A total of 55.4% of the patients in the ketamine group and 41.2% of those in the ECT group had a response (difference, 14.2 percentage points; 95% confidence interval, 3.9 to 24.2; P<0.001 for the noninferiority of ketamine to ECT). ECT appeared to be associated with a decrease in memory recall after 3 weeks of treatment (mean [±SE] decrease in the T-score for delayed recall on the Hopkins Verbal Learning Test-Revised, -0.9±1.1 in the ketamine group vs. -9.7±1.2 in the ECT group; scores range from -300 to 200, with higher scores indicating better function) with gradual recovery during follow-up. Improvement in patient-reported quality-of-life was similar in the two trial groups. ECT was associated with musculoskeletal adverse effects, whereas ketamine was associated with dissociation.

CONCLUSIONS

Ketamine was noninferior to ECT as therapy for treatment-resistant major depression without psychosis. (Funded by the Patient-Centered Outcomes Research Institute; ELEKT-D ClinicalTrials.gov number, NCT03113968.).

Why ketamine

We present the rationale for testing ketamine as an add-on therapy for treating benzodiazepine refractory (established) status epilepticus. In animal studies, ketamine terminates benzodiazepine refractory status epilepticus by interfering with the pathophysiological mechanisms and is a neuroprotectant. Ketamine does not suppress respiration when used for sedation and anesthesia. A Series of reports suggest that ketamine can help terminate refractory and super refractory status epilepticus. We propose to use 1 or 3 mg/Kg ketamine intravenously based on animal-to-human conversion and pharmacokinetic studies. This paper was presented at the 8th London-Innsbruck Colloquium on Status Epilepticus and Acute Seizures held in September 2022.

Prospective, randomised comparison of two intravenous sedation methods for magnetic resonance imaging in children

BACKGROUND

Children usually need sedation or even anaesthesia for magnetic resonance imaging (MRI) studies. As there is no universally accepted method for this purpose we undertook a prospective, randomised comparison of propofol and dexmedetomidine in children aged 1 to 10 years.

METHODS

After Institutional Board approval and parents' informed consent 64 ASA status I or II children scheduled for MRI scan were enrolled. Patients were premedicated with intravenous (IV) midazolam (0.1 mg kg -1 ) and ketamine (1 mg kg -1 ) and randomised to propofol (P) or dexmedetomidine (D) group. A propofol bolus of 1 mg kg -1 followed by infusion of 4 mg kg -1 h -1 , or dexmedetomidine 1 µg kg -1 followed by 2 µg kg -1 h-1 infusion were used. Heart rate, SpO 2 and non-invasive blood pressure were monitored and recorded at 5 min intervals. Results were compared by means of standard statistical methods.

RESULTS

Both dexmedetomidine and propofol after premedication with ketamine and midazolam are suitable for MRI sedation, although propofol use results in shorter recovery time. Less interventions are needed when dexmedetomidine is used.

Comparison of intranasal dexmedetomidine-midazolam, dexmedetomidine-ketamine, and midazolam-ketamine for premedication in paediatric patients: a double-blinded randomized trial

BACKGROUND

Paediatric patients are a population with a high level of anxiety. The prevention of perioperative stress in a frightened child is important to render the child calm and cooperative for smoother induction. Intranasal premedication is easy and safe, and the drug is rapidly absorbed into the systemic circulation, ensuring early onset of sedation in children and good effectiveness.

METHODS

150 patients in the age group 2-4 years, ASA class I, undergoing elective surgical procedures were enrolled. The patients were randomly divided into 3 groups: a DM group (receiving intranasal dexmedetomidine 1 µg kg -1 and midazolam 0.12 mg kg -1 ), a DK group (receiving intranasal dexmedetomidine 1 µg kg -1 and keta-mine 2 mg kg -1 ), and an MK group (receiving intranasal midazolam 0.12 mg kg -1 and ketamine 2 mg kg -1 ). After 30 minutes of administration of the drugs, the patients were assessed for parent separation anxiety, sedation, ease of IV cannulation, and mask acceptance.

RESULTS

The comparison among the 3 groups showed a statistically significant difference for ease of IV cannulation and mask acceptance at 30 minutes, with a P -value of 0.010 with CI of 0.0-0.02, and P -value 0.007 with CI 0.0-0.02, respectively. The parent separation anxiety and sedation score at 30 minutes was statistically insignificant with a P -value of 0.82 with CI of 0.03-0.14 and P -value 0.631 with CI of 0.38-0.58, respectively.

CONCLUSIONS

The combination of midazolam and ketamine had a better clinical profile for premedication as compared to other combination drugs used in our study in terms of IV cannulation and acceptance of masks with a comparable decrease in separation anxiety from parents and adequate sedation.

Ultrasound-guided selective peripheral nerve block compared with the sub-dissociative dose of ketamine for analgesia in patients with extremity injuries

STUDY OBJECTIVE

To compare the analgesic efficacy of ultrasound-guided selective peripheral nerve block (PNB) and sub-dissociative dose ketamine (SDK) for management of acute pain in patients with extremity injuries presenting to the emergency department (ED).

METHODS

This prospective, open-label randomized clinical trial was conducted in the ED of a tertiary care Institute. The patients were provided with either ultrasound-guided selective PNB or SDK. The primary outcome was a reduction in pain in numerical rating scale (NRS) by at least 3 points without rescue analgesia. The secondary outcomes were the need for rescue analgesia, adverse events, and patient satisfaction on either arm.

RESULTS

A total of 111 patients with isolated traumatic extremity injuries were included in the final analysis. The NRS score was significantly lower in the PNB group compared to the SDK group at 30, 60,120, 180-, and 240-min post-intervention [group ∼ time interaction, F (5, 647) = 21.53, p ≤ 0.001]. All the patients in the PNB group exhibited primary outcome (NRS ≥3 reductions) at 30 min post-intervention compared with 36 (65%) in the SDK group [-1.02(-1.422,0.622)]. Rescue analgesia was required in 10 (18%) patients in the SDK group compared to none in the PNB group [0.663(0.277,1.050)]. The decrease in NRS score from baseline at 30 min was significantly higher in PNB groups compared to the SDK group [-2.166(-2.640, -1.692)]. The most common side effect reported in the SDK group was dizziness 35(64%), followed by nausea 15(27%). None of the patients in the PNB group reported any complications. Patient satisfaction was higher in the PNB group than SDK group.

CONCLUSION

The study provides evidence that ultrasound-guided PNB is superior to SDK in terms of its analgesic efficacy in the management of acute pain due to extremity injuries and is associated with higher patient satisfaction. The need for rescue analgesia was significantly less in the PNB group. SDK was associated with a high incidence of dizziness and nausea.

The role of BDNF in mediating the prophylactic effects of (R,S)-ketamine on fear generalization and extinction

Fear generalization is a conserved survival mechanism that can become maladaptive in the face of traumatic situations, a feature central to certain anxiety disorders including posttraumatic stress disorder (PTSD). However, the neural circuitry and molecular mechanisms underlying fear generalization remain unclear. Recent studies have shown that prophylactic treatment with (R,S)-ketamine confers protective effects in stress-induced depressive behaviors and enhances contextual fear discrimination, but the extent to which these effects extend to fear generalization after auditory fear conditioning remains unclear. Here, we build on this work by using a behavioral model of fear generalization in mice involving foot shocks with differential intensity levels during auditory fear conditioning. We find that prophylactic (R,S)-ketamine treatment exerts protective effects that results in enhanced fear discrimination in wild type mice. As the growth factor, brain-derived neurotrophic factor (BDNF), has been shown to mediate the rapid antidepressant actions of (R,S)-ketamine, we used a loss-of-function BDNF mouse line (BDNF Val66Met) to determine whether BDNF is involved in (R,S)-ketamine's prophylactic effects on fear generalization. We found that BDNF Val66Met mice were resistant to the protective effects of prophylactic (R,S)-ketamine administration on fear generalization and extinction. We then used fiber photometry to parse out underlying neural activity and found that in the ventral hippocampus there were significant fear generalization-dependent patterns of activity for wild type and BDNF Val66Met mice that were altered by prophylactic (R,S)-ketamine treatment. Overall, these findings indicate a role for the ventral hippocampus and BDNF signaling in modulating the mitigating effects of prophylactic (R,S)-ketamine treatment on generalized fear.

Enhanced Fear Memories and Altered Brain Glucose Metabolism (18F-FDG-PET) following Subanesthetic Intravenous Ketamine Infusion in Female Sprague-Dawley Rats

Although women and men are equally likely to receive ketamine following traumatic injury, little is known regarding sex-related differences in the impact of ketamine on traumatic memory. We previously reported that subanesthetic doses of an intravenous (IV) ketamine infusion following fear conditioning impaired fear extinction and altered regional brain glucose metabolism (BGluM) in male rats. Here, we investigated the effects of IV ketamine infusion on fear memory, stress hormone levels, and BGluM in female rats. Adult female Sprague–Dawley rats received a single IV ketamine infusion (0, 2, 10, or 20 mg/kg, over a 2-h period) following auditory fear conditioning (three pairings of tone and footshock). Levels of plasma stress hormones, corticosterone (CORT) and progesterone, were measured after the ketamine infusion. Two days after ketamine infusion, fear memory retrieval, extinction, and renewal were tested over a three-day period. The effects of IV ketamine infusion on BGluM were determined using ¹⁸F-fluoro-deoxyglucose positron emission tomography (¹⁸F-FDG-PET) and computed tomography (CT). The 2 and 10 mg/kg ketamine infusions reduced locomotor activity, while 20 mg/kg infusion produced reduction (first hour) followed by stimulation (second hour) of activity. The 10 and 20 mg/kg ketamine infusions significantly elevated plasma CORT and progesterone levels. All three doses enhanced fear memory retrieval, impaired fear extinction, and enhanced cued fear renewal in female rats. Ketamine infusion produced dose-dependent effects on BGluM in fear- and stress-sensitive brain regions of female rats. The current findings indicate that subanesthetic doses of IV ketamine produce robust effects on the hypothalamic–pituitary–adrenal (HPA) axis and brain energy utilization that may contribute to enhanced fear memory observed in female rats.

Premature commitment to uncertain decisions during human NMDA receptor hypofunction

Making accurate decisions based on unreliable sensory evidence requires cognitive inference. Dysfunction of n-methyl-d-aspartate (NMDA) receptors impairs the integration of noisy input in theoretical models of neural circuits, but whether and how this synaptic alteration impairs human inference and confidence during uncertain decisions remains unknown. Here we use placebo-controlled infusions of ketamine to characterize the causal effect of human NMDA receptor hypofunction on cognitive inference and its neural correlates. At the behavioral level, ketamine triggers inference errors and elevated decision uncertainty. At the neural level, ketamine is associated with imbalanced coding of evidence and premature response preparation in electroencephalographic (EEG) activity. Through computational modeling of inference and confidence, we propose that this specific pattern of behavioral and neural impairments reflects an early commitment to inaccurate decisions, which aims at resolving the abnormal uncertainty generated by NMDA receptor hypofunction.

Intranasal dexmedetomidine and intranasal ketamine association allows shorter induction time for pediatric sedation compared to intranasal dexmedetomidine and oral midazolam

BACKGROUND

Non-painful diagnostic procedures require an inactive state for a prolonged time, so that sedation is often needed in younger children to perform the procedures. Our standard of care in this setting consists of the association between oral midazolam (0.5 mg/kg) and intranasal dexmedetomidine (4 mcg/kg). One of the limits of this approach is that the onset of action is quite delayed (up to 55 min) and poorly predictable. We chose to compare this association with intranasal-ketamine and intranasal-dexmedetomidine.

METHODS

This is a "pre-post" study. The study population included the first forty children receiving sedation with the "new" combination intranasal ketamine (3 mg/kg) and intranasal dexmedetomidine (4 mcg/kg) compared to a historical cohort including the last forty children receiving sedation with our standard of care combination of intranasal dexmedetomidine (4mcg/kg) and oral midazolam (0,5 mg/kg).

RESULTS

The association intranasal dexmedetomidine and intranasal ketamine allowed for a significantly shorter sedation induction time than the combination intranasal dexmedetomidine and oral midazolam (13,5 min versus 35 min). Both group's cumulative data showed a correlation between age and sedation effectiveness, with younger children presenting a higher success rate and shorter induction time (p 0,001).

CONCLUSIONS

This study suggests that the ketamine and dexmedetomidine intranasal association may have a shorter onset of action when compared to intranasal dexmedetomidine and oral midazolam.

Low-dose Ketamine Infusion for Pediatric Hematology/Oncology Patients: Case Series and Literature Review

Management of refractory pain in pediatric sickle cell disease (SCD) and oncology is reliant on opioids though high opioid dosing increases side effects and tachyphylaxis. We introduced low-dose ketamine infusion (LDKI) to our inpatient unit to determine if LDKI was tolerable. We subsequently hypothesized that LDKI would improve pain scores. We reviewed inpatients from LDKI initiation in March 2014 through October 2017, with the day before LDKI initiation compared with the day of LDKI initiation and 2 subsequent days. For patients with SCD, the LDKI admission was compared with up to 3 admissions in the prior year for a vaso-occlusive event. Nineteen patients (12 oncology, 7 SCD) with a median age of 14.6 years received LDKI for a median of 6 days at a median initial dose of 0.06 mg/kg/h (1.1 µg/kg/min). There was no change in pain scores or opioid utilization when comparing the day before LDKI initiation with subsequent days. No patient discontinued LDKI because of intolerability. For patients with SCD, there was a median 32% reduction in cumulative pain scores when comparing the LDKI admission with prior admissions. LDKI is well tolerated for refractory pediatric cancer-related and sickle cell-related pain.

A randomized, multicenter trial assessing the effects of rapastinel compared to ketamine, alprazolam, and placebo on simulated driving performance

N-methyl-D-aspartate ionotropic glutamatergic receptor (NMDAR) modulators, including rapastinel and ketamine, elicit rapid and sustained antidepressant responses in patients with treatment-resistant major depressive disorder. This phase I, randomized, multicenter, placebo-controlled, five-period, crossover, single-dose study evaluated simulated driving performance of healthy participants (N = 107) after single doses of rapastinel slow intravenous (i.v.) bolus 900 and 1800 mg, alprazolam oral 0.75 mg (positive control), ketamine i.v. infusion 0.5 mg/kg (clinical comparator), and placebo ~ 45 min before driving. The primary end point was SD of lateral position (SDLP) during the 60-min 100-km simulated driving scenario. Additional measures of driving performance, sleepiness, and cognition were also evaluated. To assess effects over time, mean SDLP was calculated for each 10-min interval of driving. Sensitivity of the assays was confirmed with alprazolam (all placebo comparisons p < 0.02). Rapastinel 900 and 1800 mg did not significantly affect simulated driving performance compared to placebo (both p > 0.5). Both rapastinel doses resulted in significantly less impaired driving compared to alprazolam or ketamine (all p < 0.002); ketamine significantly impaired driving compared to placebo (p = 0.0001). Results for the additional measures were similar to the primary end point. No new safety signals were observed for any study interventions. This first study of rapastinel effects on simulated driving found that rapastinel 900 and 1800 mg did not impair driving performance, but ketamine 0.5 mg/kg resulted in significantly impaired driving performance. Ketamine's effects on driving were maintained for at least 105 min, indicating that clinicians should be vigilant to prevent or postpone driving in patients after ketamine treatment.

Minimally invasive protocols and quantification for microglia-mediated perineuronal net disassembly in mouse brain

Enzymatic digestion of the extracellular matrix with chondroitinase-ABC reinstates juvenile-like plasticity in the adult cortex as it also disassembles the perineuronal nets (PNNs). The disadvantage of the enzyme is that it must be applied intracerebrally and it degrades the ECM for several weeks. Here, we provide two minimally invasive and transient protocols for microglia-enabled PNN disassembly in mouse cortex: repeated treatment with ketamine-xylazine-acepromazine (KXA) anesthesia and 60-Hz light entrainment. We also discuss how to analyze PNNs within microglial endosomes-lysosomes.

For complete details on the use and execution of this protocol, please refer to Venturino et al. (2021).

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PNN disassembly with repeated ketamine-mediated anesthesia in mice

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60 Hz light entrainment as an alternative approach

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Strategy to quantify density of PNN-coated cells

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Determine PNN material enriched within microglial lysosomes

Diazepam Monotherapy or Diazepam-Ketamine Dual Therapy at Different Time Points Terminates Seizures and Reduces Mortality in a Status Epilepticus Animal Model

BACKGROUND Being refractory to drugs remains an urgent treatment problem in status epilepticus (SE). The fact that γ-aminobutyric acid A receptors (GABAARs) become internalized and inactive, N-methyl-D-aspartate receptors (NMDARs) become externalized and active during SE may explain the refractoriness to benzodiazepine. However, the real-time dynamic efficacy of antiepileptic drugs remains unclear. Therefore, we propose a hypothesis that diazepam monotherapy or diazepam-ketamine dual therapy could terminate seizures and reduce mortality in the SE model at different time points during ongoing SE. MATERIAL AND METHODS An SE model was established in adult Sprague-Dawley rats with lithium and pilocarpine. The GABAAR agonist diazepam was injected at 5, 10, 20, or 30 min when SE continued. In addition, diazepam and the NMDAR antagonist ketamine were injected at 10 to 60 min at 6 different time points. We measured seizure-free rates, seizure duration, degree of behavioral seizure, and mortality. RESULTS Diazepam monotherapy at 5 min and 10 min from the beginning of SE was able to terminate seizures and improved survival rates. Diazepam-ketamine dual therapy at 10 min, 20 min, and 30 min from the beginning of SE terminated seizures and achieved high survival rates. CONCLUSIONS In this parallel randomized controlled trial with a rat model, we found that diazepam monotherapy was an effective antiepileptic strategy at the early stage of SE less than 10 min after SE onset. If SE lasts more than 10 min but less than 30 min, the diazepam-ketamine dual therapy strategy may be an appropriate choice.

Ketamine for critically ill patients with severe acute brain injury: Protocol for a systematic review with meta-analysis and Trial Sequential Analysis of randomised clinical trials

INTRODUCTION

Intensive care for patients with severe acute brain injury aims both to treat the immediate consequences of the injury and to prevent and treat secondary brain injury to ensure a good functional outcome. Sedation may be used to facilitate mechanical ventilation, for treating agitation, and for controlling intracranial pressure. Ketamine is an N-methyl-D-aspartate receptor antagonist with sedative, analgesic, and potentially neuroprotective properties. We describe a protocol for a systematic review of randomised clinical trials assessing the beneficial and harmful effects of ketamine for patients with severe acute brain injury.

METHODS AND ANALYSIS

We will systematically search international databases for randomised clinical trials, including CENTRAL, MEDLINE, Embase, and trial registries. Two authors will independently review and select trials for inclusion, and extract data. We will compare ketamine by any regimen versus placebo, no intervention, or other sedatives or analgesics for patients with severe acute brain injury. The primary outcomes will be functional outcome at maximal follow up, quality of life, and serious adverse events. We will also assess secondary and exploratory outcomes. The extracted data will be analysed using Review Manager and Trials Sequential Analysis. Evidence certainty will be graded using GRADE.

ETHICS AND DISSEMINATION

The results of the systematic review will be disseminated through peer-reviewed publication. With the review, we hope to inform future randomised clinical trials and improve clinical practice.

PROSPERO NO

CRD42021210447.

Influence of ketamine versus fentanyl on pain relief for pediatric orthopedic emergencies: A meta-analysis of randomized controlled studies

INTRODUCTION

The comparison of ketamine with fentanyl for pain control of pediatric orthopedic emergencies remains controversial. We conduct a systematic review and meta-analysis to explore the influence of ketamine versus fentanyl on pain management among pediatric orthopedic emergencies.

METHODS

We have searched PubMed, EMbase, Web of science, EBSCO, and Cochrane library databases through September 2020 for randomized controlled trials assessing the effect of ketamine versus fentanyl on pain management for pediatric orthopedic emergencies.

RESULTS

Five randomized controlled trials are included in the meta-analysis. Overall, compared with fentanyl for pediatric orthopedic emergencies, ketamine led to similar change in pain scores at 15 to 20 minutes (standard mean difference = -0.05; 95% confidence interval [CI] = -0.38 to 0.28; P = .77) and 30 minutes (standard mean difference = 0.11; 95% CI = -0.20 to 0.42; P = .49), as well as rescue analgesia (RR = 0.90; 95% CI = 0.54 to 1.51; P = .69), but revealed the increase in nausea/vomiting (RR = 2.65; 95% CI = 1.13 to 6.18; P = .02) and dizziness (RR = 3.83; 95% CI = 1.38 to 10.60; P = .01).

CONCLUSIONS

Ketamine may be similar to fentanyl in terms of the analgesic efficacy for pediatric orthopedic emergencies.

Esketamine Nasal Spray for the Rapid Reduction of Depressive Symptoms in Major Depressive Disorder With Acute Suicidal Ideation or Behavior

PURPOSE/BACKGROUND

Numerous health authority approvals of esketamine nasal spray, combined with oral antidepressant, to treat depressive symptoms in adults with major depressive disorder and acute suicidal ideation or behavior were based on 2 identically designed, double-blind, phase 3 studies.

METHODS/PROCEDURES

Across both ASPIRE studies (NCT03039192, NCT03097133), patients (N = 456) were randomized to esketamine 84 mg or placebo nasal spray twice weekly for 4 weeks plus comprehensive standard of care, including hospitalization and newly initiated or optimized antidepressant(s). In post hoc analyses of pooled data, changes from baseline at 24 hours after the first dose in Montgomery-Åsberg Depression Rating Scale total score and Clinical Global Impression-Severity of Suicidality-Revised, in the full cohort and in subgroups, were analyzed using analysis of covariance.

FINDINGS/RESULTS

Esketamine plus standard of care demonstrated significantly greater improvement in Montgomery-Åsberg Depression Rating Scale total score versus placebo plus standard of care at 24 hours (least square mean difference [95% confidence interval], -3.8 [-5.75 to -1.89]) and at earlier (4 hours: -3.4 [-5.05 to -1.71]) and later time points (day 25: -3.4 [-5.36 to -1.36]). The between-group difference (95% confidence interval) for change in Clinical Global Impression-Severity of Suicidality-Revised at 24 hours was -0.20 (-0.43 to 0.04) for all patients and -0.31 (-0.61 to -0.01) for those with a history of suicide attempt. Common adverse events (≥20%) during esketamine treatment were dizziness, dissociation, nausea, somnolence, and headache.

IMPLICATIONS/CONCLUSIONS

Esketamine plus comprehensive standard of care rapidly reduces depressive symptoms in patients with major depressive disorder who have acute suicidal ideation or behavior, especially in those with a history of suicide attempt, providing a new treatment option for this particularly ill and vulnerable population.

Long-Term Efficacy of Intranasal Esketamine in Treatment-Resistant Major Depression: A Systematic Review

Esketamine (ESK) has been approved as a rapid-acting intranasal treatment for treatment-resistant depression (TRD). Although existing studies have investigated the efficacy of ESK in the 4-week induction phase, our knowledge about long-term ESK efficacy remains poor. The aim of this systematic review was to summarize the available data on long-term ESK efficacy for TRD. A systematic search was performed including articles in English, up to 31 March 2021. The search found 7 relevant studies, involving 1024 adult TRD patients. Continuing treatment with ESK after the 4-week induction phase may be associated with stable efficacy in relapse prevention among TRD patients. Conversely, the long-term antidepressant effectiveness upon discontinuation of ESK might be limited, although data from three studies had a moderate to high risk of bias. Overall, the results on the effectiveness of this compound in the long term are mixed. According to our findings, ESK treatment should be continued following the induction phase to reach a stable efficacy in relapse prevention, while the long-term antidepressant and anti-suicidal effects of ESK after discontinuation are inconsistent. Currently, the level of proof of ESK efficacy in long-term TRD treatment remains low and more RCTs with larger sample sizes and active comparators are needed.

Subanesthetic ketamine rapidly alters medial prefrontal miRNAs involved in ubiquitin-mediated proteolysis

Ketamine is a dissociative anesthetic and a non-competitive NMDAR antagonist. At subanesthetic dose, ketamine can relieve pain and work as a fast-acting antidepressant, but the underlying molecular mechanism remains elusive. This study aimed to investigate the mode of action underlying the effects of acute subanesthetic ketamine treatment by bioinformatics analyses of miRNAs in the medial prefrontal cortex of male C57BL/6J mice. Gene Ontology and KEGG pathway analyses of the genes putatively targeted by ketamine-responsive prefrontal miRNAs revealed that acute subanesthetic ketamine modifies ubiquitin-mediated proteolysis. Validation analysis suggested that miR-148a-3p and miR-128-3p are the main players responsible for the subanesthetic ketamine-mediated alteration of ubiquitin-mediated proteolysis through varied regulation of ubiquitin ligases E2 and E3. Collectively, our data imply that the prefrontal miRNA-dependent modulation of ubiquitin-mediated proteolysis is at least partially involved in the mode of action by acute subanesthetic ketamine treatment.

Pediatric Sedation in the Emergency Department: Trends from a Nationwide Population-based Study in Korea, 2007-2018

BACKGROUND

Pediatric sedation in the emergency department (ED) is widely performed in Korea; thus exploring the trends of its use is necessary. This study aimed to investigate the characteristics of patients and sedatives use in the ED and verify their changes over recent years.

METHODS

A nationwide population-based retrospective study was conducted including pediatric patients aged ≤ 15 years who received sedative medication in the ED and were discharged during 2007-2018, using the Korean Health Insurance Review and Assessment Service database. Patient characteristics (age, sex, level of ED, and diagnosis) and type of sedative used were analyzed.

RESULTS

Sedation was performed in total 468,221 visits during 2007-2018 (399,320 visits, at least 3.8% of overall ED visits during 2009-2018). Among these, 71.0% were children aged 1-3 years and 93.5% were sedated to support diagnosis of injury. An increase in total sedation was observed in patients aged 4-6 years during the study period (from 13.8% to 21.8%). A gradual decrease in the use of chloral hydrate (CH) compared with an increase in ketamine use was observed (CH, from 70.6% to 28.6%; ketamine, from 23.8% to 60.7%). Therefore, ketamine was the most used sedative since 2014. The most frequently used sedatives over the study period differed according to age groups (CH in <1 year and 1-3 years; ketamine in 4-6 years and 7-10 years; and midazolam in 11-15 years).

CONCLUSIONS

The characteristics of patients related to sedatives use in the ED have changed over time. These changes should be considered in the development of future Korean guidelines regarding pediatric sedation in the ED.

Dissociative symptoms with intravenous ketamine in treatment-resistant depression exploratory observational study

There is evidence for ketamine use in treatment-resistant depression (TRD). Several safety and tolerability concerns arise regarding adverse drug reactions and specific subpopulations. This paper aims to investigate the relationship between dissociative and psychometric measures in course of intravenous ketamine treatment in TRD inpatients with major depressive disorder and bipolar disorder.This study result represents safety data in a population of 49 inpatients with major depressive disorder and bipolar disorder subjects receiving eight 0.5 mg/kg of ketamine intravenous infusions, with a duration of 40 min each, as an add-on treatment to standard-of-care pharmacotherapy, registered in the naturalistic observational protocol of the tertiary reference unit for mood disorders (NCT04226963). The safety psychometrics assessed dissociation and psychomimetic symptomatology with the Clinician-Administered Dissociative States Scale (CADSS) the Brief Psychiatric Rating Scale (BPRS).The significant differences in CADSS scores between measurements in course of the treatment were observed (P = .003). No significant differences between BPRS measurements were made after infusions. In each case, both BPRS and CADSS values dropped to the "absent" level within 1 hour from the infusion. Neither CADSS nor BPRS scores were associated with the treatment outcome.The study demonstrates a good safety profile of intravenous ketamine as an add-on intervention to current psychotropic medication in TRD. The abatement of dissociation was observed in time with no sequelae nor harm. The study provides no support for the association between dissociation and treatment outcome.This study may be underpowered due to the small sample size. The protocol was defined as a study on acute depressive symptomatology without blinding.

Cognitive function after electroconvulsive therapy for depression: relationship to clinical response

BACKGROUND

As uncertainty remains about whether clinical response influences cognitive function after electroconvulsive therapy (ECT) for depression, we examined the effect of remission status on cognitive function in depressed patients 4 months after a course of ECT.

METHOD

A secondary analysis was undertaken on participants completing a randomised controlled trial of ketamine augmentation of ECT for depression who were categorised by remission status (MADRS ⩽10 v. >10) 4 months after ECT. Cognition was assessed with self-rated memory and neuropsychological tests of anterograde verbal and visual memory, autobiographical memory, verbal fluency and working memory. Patients were assessed through the study, healthy controls on a single occasion, and compared using analysis of variance.

RESULTS

At 4-month follow-up, remitted patients (N = 18) had a mean MADRS depression score of 3.8 (95% CI 2.2-5.4) compared with 27.2 (23.0-31.5) in non-remitted patients (N = 19), with no significant baseline differences between the two groups. Patients were impaired on all cognitive measures at baseline. There was no deterioration, with some measures improving, 4-months after ECT, at which time remitted patients had significantly improved self-rated memory, anterograde verbal memory and category verbal fluency compared with those remaining depressed. Self-rated memory correlated with category fluency and autobiographical memory at follow-up.

CONCLUSIONS

We found no evidence of persistent impairment of cognition after ECT. Achieving remission improved subjective memory and verbal memory recall, but other aspects of cognitive function were not influenced by remission status. Self-rated memory may be useful to monitor the effects of ECT on longer-term memory.

Co-administration of cannabidiol and ketamine induces antidepressant-like effects devoid of hyperlocomotor side-effects

BACKGROUND AND PURPOSE

Although useful as a rapid-acting antidepressant drug, ketamine is known to induce psychotomimetic effects, which may interfere with its therapeutic use. Cannabidiol (CBD) is a non-psychostimulant compound from Cannabis sativa, which has shown promising antidepressant effects without inducing hyperlocomotion. AMPA receptor activation is involved in the antidepressant effect induced by ketamine, but its relevance for the effects of CBD is not known. Moreover, given that CBD has antipsychotic and antidepressant properties, it is unknown whether adding CBD to ketamine could potentiate the antidepressant properties of ketamine while also attenuating its psychostimulant effects.

EXPERIMENTAL APPROACH

S-Ketamine (2.5, 3, 5, 10, 30 mg/kg) and cannabidiol (3, 10, 30 mg/kg) were administered alone or in combination to male Swiss mice. Independent groups received NBQX (AMPA receptor antagonist) 5 min before administration of CBD or S-ketamine. The antidepressant-like effect was assessed in the forced swimming test (FST), and the open field test (OFT) evaluated the psychostimulant effect.

KEY RESULTS

CBD induced significant dose-dependent antidepressant effects without causing hyperlocomotion in the OFT. S-ketamine produced an antidepressant effect associated with hyperlocomotion in the higher dose. NBQX inhibited the antidepressant effect of both ketamine and CBD. Pretreatment with CBD (10 mg/kg) attenuated the ketamine-induced hyperlocomotion while preserving its antidepressant effect.

CONCLUSION

AND IMPLICATIONS: Similar to ketamine, the antidepressant-like effect elicited by CBD involves AMPA receptor activation. Additionally, CBD prevents the hyperlocomotion induced by S-ketamine without affecting its antidepressant-like effect. Our findings suggest that CBD and ketamine's combined administration can be a promising therapeutic strategy for achieving an appropriate antidepressant effect without unwanted side-effects. This article is part of the special issue on 'Cannabinoids'.

Out-of-Hospital Ketamine: Indications for Use, Patient Outcomes, and Associated Mortality

STUDY OBJECTIVE

To describe out-of-hospital ketamine use, patient outcomes, and the potential contribution of ketamine to patient death.

METHODS

We retrospectively evaluated consecutive occurrences of out-of-hospital ketamine administration from January 1, 2019 to December 31, 2019 reported to the national ESO Data Collaborative (Austin, TX), a consortium of 1,322 emergency medical service agencies distributed throughout the United States. We descriptively assessed indications for ketamine administration, dosing, route, transport disposition, hypoxia, hypercapnia, and mortality. We reviewed cases involving patient death to determine whether ketamine could be excluded as a potential contributing factor.

RESULTS

Indications for out-of-hospital ketamine administrations in our 11,291 patients were trauma/pain (49%; n=5,575), altered mental status/behavioral indications (34%; n=3,795), cardiovascular/pulmonary indications (13%; n=1,454), seizure (2%; n=248), and other (2%; n=219). The highest median dose was for altered mental status/behavioral indications at 3.7 mg/kg (interquartile range, 2.2 to 4.4 mg/kg). Over 99% of patients (n=11,274) were transported to a hospital. Following ketamine administration, hypoxia and hypercapnia were documented in 8.4% (n=897) and 17.2% (n=1,311) of patients, respectively. Eight on-scene and 120 in-hospital deaths were reviewed. Ketamine could not be excluded as a contributing factor in 2 on-scene deaths, representing 0.02% (95% confidence interval 0.00% to 0.07%) of those who received out-of-hospital ketamine. Among those with in-hospital data, ketamine could not be excluded as a contributing factor in 6 deaths (0.3%; 95% confidence interval 0.1% to 0.7%).

CONCLUSION

In this large sample, out-of-hospital ketamine was administered for a variety of indications. Patient mortality was rare. Ketamine could not be ruled out as a contributing factor in 8 deaths, representing 0.07% of those who received ketamine.

A multicenter investigation of the hemodynamic effects of induction agents for trauma rapid sequence intubation

BACKGROUND

Several options exist for induction agents during rapid sequence intubation (RSI) in trauma patients, including etomidate, ketamine, and propofol. These drugs have reported variable hemodynamic effects (hypotension with propofol and sympathomimetic effects with ketamine) that could affect trauma resuscitations. The purpose of this study was to compare the hemodynamic effects of these three induction agents during emergency department RSI in adult trauma. We hypothesized that these drugs would display a differing hemodynamic profile during RSI.

METHODS

We performed a retrospective (2014-2019), multicenter trial of adult (≥18 years) trauma patients admitted to eight ACS-verified Level I trauma centers who underwent emergency department RSI. Variables collected included systolic blood pressure (SBP) and pulse before and after RSI. The primary outcomes were change in heart rate and SBP before and after RSI.

RESULTS

There were 2,092 patients who met criteria, 85% received etomidate (E), 8% ketamine (K), and 7% propofol (P). Before RSI, the ketamine group had a lower SBP (E, 135 vs. K, 125 vs. P, 135 mm Hg, p = 0.04) but there was no difference in pulse (E, 104 vs. K, 107 vs. P, 105 bpm, p = 0.45). After RSI, there were no differences in SBP (E, 135 vs. K, 130 vs. P, 133 mm Hg, p = 0.34) or pulse (E, 106 vs. K, 110 vs. P, 104 bpm, p = 0.08). There was no difference in the average change of SBP (E, 0.2 vs. K, 5.2 vs. P, -1.8 mm Hg, p = 0.4) or pulse (E, 1.7 vs. K, 3.5 bpm vs. P, -0.96, p = 0.24) during RSI.

CONCLUSION

Contrary to our hypothesis, there was no difference in the hemodynamic effect for etomidate versus ketamine versus propofol during RSI in trauma patients.

LEVEL OF EVIDENCE

Therapeutic, Level IV.

Procedural Sedation for Pediatric Upper Gastrointestinal Endoscopy in Korea

BACKGROUND

Sedative upper endoscopy is similar in pediatrics and adults, but it is characteristically more likely to lead to respiratory failure. Although recommended guidelines for pediatric procedural sedation are available within South Korea and internationally, Korean pediatric endoscopists use different drugs, either alone or in combination, in practice. Efforts are being made to minimize the risk of sedation while avoiding procedural challenges. The purpose of this study was to collect and analyze data on the sedation methods used by Korean pediatric endoscopists to help physicians perform pediatric sedative upper endoscopy (PSUE).

METHODS

The PSUE procedures performed in 15 Korean pediatric gastrointestinal endoscopic units within a year were analyzed. Drugs used for sedation were grouped according to the method of use, and the depth of sedation was evaluated based on the Ramsay scores. The procedures and their complications were also assessed.

RESULTS

In total, 734 patients who underwent PSUE were included. Sedation and monitoring were performed by an anesthesiologist at one of the institutions. The sedative procedures were performed by a pediatric endoscopist at the other 14 institutions. Regarding the number of assistants present during the procedures, 36.6% of procedures had one assistant, 38.8% had 2 assistants, and 24.5% had 3 assistants. The average age of the patients was 11.6 years old. Of the patients, 19.8% had underlying diseases, 10.0% were taking medications such as epilepsy drugs, and 1.0% had snoring or sleep apnea history. The average duration of the procedures was 5.2 minutes. The subjects were divided into 5 groups as follows: 1) midazolam + propofol + ketamine (M + P + K): n = 18, average dose of 0.03 + 2.4 + 0.5 mg/kg; 2) M + P: n = 206, average dose of 0.06 + 2.1 mg/kg; 3) M + K: n = 267, average dose of 0.09 + 0.69 mg/kg; 4) continuous P infusion for 20 minutes: n = 15, average dose of 6.6 mg/kg; 5) M: n = 228, average dose of 0.11 mg/kg. The average Ramsay score for the five groups was 3.7, with significant differences between the groups (P < 0.001). Regarding the adverse effects, desaturation and increased oxygen supply were most prevalent in the M + K group. Decreases and increases in blood pressure were most prevalent in the M + P + K group, and bag-mask ventilation was most used in the M + K group. There were no reported incidents of intubation or cardiopulmonary resuscitation. A decrease in oxygen saturation was observed in 37 of 734 patients, and it significantly increased in young patients (P = 0.001) and when ketamine was used (P = 0.014). Oxygen saturation was also correlated with dosage (P = 0.037). The use of ketamine (P < 0.001) and propofol (P < 0.001) were identified as factors affecting the Ramsay score in the logistic regression analysis.

CONCLUSION

Although the drug use by Korean pediatric endoscopists followed the recommended guidelines to an extent, it was apparent that they combined the drugs or reduced the doses depending on the patient characteristics to reduce the likelihood of respiratory failure. Inducing deep sedation facilitates comfort during the procedure, but it also leads to a higher risk of complications.