S(+)-ketamine : Current trends in emergency and intensive care medicine

The ketamine chameleon: history, pharmacology, and the contested value of experience

INTRODUCTION

Since its synthesis in 1962, ketamine has been widely used in diverse medical contexts, from anesthesia to treatment-resistant depression. However, interpretations of ketamine's subjective effects remain polarized. Biomedical frameworks typically construe the drug's experiential effects as dissociative or psychotomimetic, while psychedelic paradigms emphasize the potential therapeutic merits of these non-ordinary states.

AREAS COVERED

Ketamine's psychoactive effects have inspired diverse interpretations. In this review, we trace the historical evolution of these perspectives - which we broadly categorize as 'dissociative,' 'dream-like,' and 'psychedelic' - and show how they emerged out of these clinical contexts. We highlight the influence of factors such as language, dose, and environmental context on ketamine's effects and therapeutic outcomes. We discuss potential mechanisms underlying these context-dependent effects and explore the broader clinical and research-related ramifications.

EXPERT OPINION

Ketamine's subjective effects are undeniably powerful, yet their therapeutic significance remains debated. A nuanced, interdisciplinary approach is essential for maximizing ketamine's potential. Future research should focus on how explanatory models, treatment environments, and patient preparation can optimize ketamine's benefits while minimizing distress. We suggest that, rather than being a tiger to be tamed as its creator once described, ketamine may best be understood as a chameleon whose color shifts depending on its context.

Induction Agents for Tracheal Intubation in Critically Ill Patients

OBJECTIVES

Concise definitive review of the use of induction agents in critically ill patients undergoing tracheal intubation and their association with outcomes.

DATA SOURCES

Original publications were retrieved through a PubMed search with search terms related to induction agents for tracheal intubation in critically ill patients.

STUDY SELECTION

We included randomized controlled trials and observational studies that reported patient outcomes.

DATA EXTRACTION

Data from included studies, including choice of induction agents and clinically relevant outcomes, were extracted.

DATA SYNTHESIS

Etomidate and ketamine have been the most studied induction agents in critical care during last years. Recent studies on etomidate investigated the clinical impact of its recognized adrenal suppression in terms of morbidity and mortality. Etomidate may carry a non-negligible mortality risk without definitive hemodynamic benefits compared with ketamine. Available data then support the use of ketamine over etomidate, since the difference in the hemodynamic profile seems to be of minor clinical relevance. No multicenter randomized studies are available comparing propofol to other induction agents but evidence from a large observational study identified an association of propofol with post-intubation cardiovascular instability in critically ill patients. Despite the observational nature of these findings cannot exclude the role of confounders, the association of propofol with post-induction cardiovascular instability is pharmacologically plausible, justifying its avoidance in favor of drugs with a better safety profile in critical care such as ketamine.

CONCLUSIONS

Although no definitive conclusions can be drawn based on the available evidence, recent evidence pointed out the potential negative effect of etomidate on survival and the association of propofol with cardiovascular instability. Ketamine may be considered the drug with a safer profile, widespread availability and low cost but future research should provide definitive data on optimal drug selection, its dosage in the context of critical illness and concomitant interventions to minimize the risk of peri-intubation complications.

Effect of esketamine on postoperative quality of recovery in patients undergoing arthroscopic rotator cuff repair: protocol for a prospective, randomized, double-blind study

BACKGROUND

The utilization of shoulder arthroscopic surgery has progressively increased as a prevalent surgical approach for the treatment and repair of rotator cuff injury in clinical practice. However, early postoperative pain and neurological dysfunction remain significant factors that impact patients' postoperative recovery. Esketamine, an NMDA receptor antagonist, effectively reduces opioid consumption, attenuates postoperative inflammatory reactivity, and has also demonstrated neuroprotective effects. The aim of this study is to evaluate the quality of early recovery after anesthesia maintenance with esketamine in patients undergoing arthroscopic rotator cuff repair.

METHODS

This is a single-center, randomized controlled trial. A total of 234 patients undergoing arthroscopic rotator cuff repair will be enrolled and randomized at a 1:1:1 ratio to receive general anesthesia with different doses of esketamine or saline solution. The primary outcome is the quality of early recovery scores based on the QoR-15 scale on postoperative day 1. Secondary outcomes include the quality of early recovery scores based on the QoR-15 scale on postoperative day 3, remifentanil consumption, use of vasoactive drugs, cerebral desaturation events, rescue analgesia during the post-anesthesia care unit stay, NRS pain scores on postoperative days 1 and 2, delirium within 3 days after surgery, and adverse events.

DISCUSSION

A randomized controlled trial design will be used in this study to assess the quality of early recovery scores in patients undergoing arthroscopic rotator cuff repair. Our objective is to investigate the potential of esketamine in mitigating the adverse effects associated with intraoperative controlled hypotension and assessing its impact on intraoperative cerebral oxygen saturation and postoperative delirium. Although this study is conducted at a single center, and there is limited research on the long-term effects of perioperative esketamine on patients, it still offers valuable insights for future studies.

TRIAL REGISTRATION

This study has been approved by the Ethics Committee at West China Hospital, Sichuan University (approval no. 2023-2282). Trial registration number ChiCTR2400080589. Registered on 2024.02.01.

The role of ketamine and its enantiomer in managing depression and pain in cancer patients: A narrative review

Depression and pain are common comorbidities in cancer patients, and ketamine, a dissociative anesthetic, has shown potential in managing both. This review summarizes current literature on ketamine and its enantiomer, esketamine, in managing depression and pain in the oncologic population. Studies indicate that sub-anesthetic doses of intravenous ketamine and esketamine can alleviate postoperative depressive symptoms in cancer patients with a tolerable safety profile. Research into non-intravenous routes for depression management in the oncologic population remains limited. Ketamine has also proven effective in managing acute postoperative pain, particularly through intravenous administration. While alternative administration routes, such as local infiltration and intramuscular methods, show mixed results, they may provide viable options for patients averse to intravenous (IV). However, the effectiveness of ketamine for chronic cancer pain remains inconsistent. Overall, ketamine offers a promising approach for managing depression and pain in oncologic patients.

Effect of esketamine on postoperative delirium in general anesthesia patients undergoing elective surgery: a meta-analysis of randomized controlled trials

BACKGROUND

Postoperative delirium is a common neurological complication, especially in older patients undergoing surgery, which is closely related to the poor prognosis of patients. The objective was to investigate the effects of esketamine on postoperative delirium in patients with general anesthesia.

METHODS

The databases of PubMed, Embase, Cochrane Library and the Chinese National Knowledge Infrastructure were searched for all available randomised controlled trials on the effects of esketamine induction on postoperative delirium in patients undergoing elective general anesthesia from inception until April 21, 2024. We used RevMan5.4 software for data analysis. Dichotomous data was analyzed by risk ratios(RR) with a 95% confidence interval(CI), and continuous data by mean differences(MD). We also evaluated the risk of literature bias using the Cochrane Bias Risk Assessment tool.

RESULTS

We included a total of 17 randomized controlled trials, including 1286 patients undergoing elective general anesthesia. In 17 studies, esketamine significantly reduced the incidence of postoperative delirium (RR: 0.43; 95%CI: 0.33 ~ 0.57; p < 0.001). Five studies examined the incidence of postoperative adverse events (nausea, vomiting, dizziness and resporatory depression) and showed no statistically significant difference between the esketamine group and the control group (normal saline or dexmedetomidine) (RR: 0.82; 95%CI: 0.65 ~ 1.03; p = 0.08). In addition, this study found that the esketamine group had a lower incidence of hypotension (RR: 0.24; 95%CI: 0.12 ~ 0.48; p < 0.001) and a lower score on the visual analogue scale 24 h after surgery (MD: -0.44; 95%CI: -0.54 ~ -0.33; p < 0.001).

CONCLUSION

According to our meta-analysis, the use of esketamine during anesthesia induction significantly reduced the incidence of postoperative delirium in patients undergoing elective general anesthesia without increasing the incidence of postoperative adverse reactions.

Investigating Strategies to Enhance the Aqueous Solubility of Ketamine HCl for Intranasal Delivery

Background: Ketamine HCl, an FDA-approved therapeutic, is administered through various routes, including intranasal delivery. Administering an adequate therapeutic dose of intranasal ketamine HCl is challenging due to the limited volume that can be delivered intranasally given the current commercially available concentrations. Objectives: This study investigates solubilizing strategies to enhance the aqueous solubility of ketamine HCl for intranasal administration. Methods: We assessed the solubility profile of ketamine HCl by evaluating factors such as pH, co-solvents, and surfactants. Additionally, we developed and validated a UV-Vis spectroscopy method for ketamine HCl analysis. Results: Our solubility screening in various organic co-solvents revealed the following order of effectiveness in enhancing solubility: methanol > water > propylene glycol > ethanol > dimethyl sulfoxide (DMSO) > N-methyl-2-pyrrolidone (NMP). Despite methanol's superior solubility, its potential toxicity, coupled with the relatively lower effectiveness of other solvents compared to water, suggests that a co-solvency approach is not advantageous for ketamine HCl. We found that ketamine HCl solubility increased with medium acidity, with pH 3.5 being the optimal for further formulation studies. The impact of pharmaceutical surfactants on ketamine HCl solubility at an acidic pH was also evaluated. Surfactants tested included SDS, PEG 400, PVP, Tween 20, poloxamer 188, and lecithin. Notably, PEG 400 and PVP reduced solubility due to a salting-out effect, whereas Tween 80, lecithin, and poloxamer 188 slightly improved solubility through micelle formation. Among the surfactants tested, 1% SDS emerged as the most effective in enhancing ketamine HCl solubility. Conclusions: These outcomes highlight the potential of these solubilization strategies to address the solubility limitations of ketamine HCl, enabling the preparation of highly concentrated ketamine HCl formulations for intranasal delivery.

Esketamine administered epidurally as an adjuvant to epidural ropivacaine for labour analgesia: a prospective, double-blind dose-response study

OBJECTIVE

To investigate the efficacy of esketamine as an adjuvant to epidural ropivacaine for labour analgesia by determining its effect on the median effective concentration (EC50) in a 20 ml volume of ropivacaine.

DESIGN

A prospective, double-blind dose-response study.

SETTING

This study was conducted in Women's Hospital, School of Medicine, Zhejiang University, China.

PARTICIPANTS

One hundred and fifty parturients who requested epidural analgesia were recruited in this study to randomly receive epidural ropivacaine alone or with esketamine of 0.2 mg ml-1, 0.3 mg ml-1, 0.4 mg ml-1 or 0.5 mg ml-1, respectively.

PRIMARY AND SECONDARY OUTCOME MEASURES

The primary outcome, EC50 of ropivacaine, was determined using an up-down sequential allocation technique. The secondary outcomes were analgesia characteristics, Ramsay Sedation Scale score, labour duration, caesarean section rate and adverse effects.

RESULTS

The EC50 of ropivacaine with the addition of esketamine at concentrations of 0.3 mg ml-1, 0.4 mg ml-1 and 0.5 mg ml-1 resulted in significant reductions in the EC50 of ropivacaine to 0.050%, 0.044% and 0.043%, respectively, from baseline (esketamine 0 mg ml-1) (p<0.0001). However, reductions of the EC50 of ropivacaine were similar among the groups with esketamine of 0.3 mg ml-1, 0.4 mg ml-1 and 0.5 mg ml-1 (p>0.05). The Ramsay Sedation Scale score was higher and more dizziness was observed in the Group of esketamine 0.5 mg ml-1 compared with all other groups (p<0.0001). During the peripartum period, no differences in sensory blockade level, Bromage score, labour duration and percentage of caesarean delivery were found among the groups.

CONCLUSIONS

Under the conditions of this study, the addition of epidural esketamine of 0.3 mg⋅mL-1, 0.4 mg⋅mL-1 and 0.5 mg⋅mL-1 offered a similar ropivacaine dose-sparing effect; 0.5 mg⋅mL-1 of esketamine produced more adverse effects.

TRIAL REGISTRATION NUMBER

ChiCTR2100054348.

Effect of small dose esketamine on perioperative neurocognitive disorder and postoperative depressive symptoms in elderly patients undergoing major elective noncardiac surgery for malignant tumors: A randomized clinical trial

BACKGROUND

Perioperative neurocognitive disorder and postoperative depressive symptoms are significant complications after surgery. Studies have indicated that esketamine possesses neuroprotective and antidepressant qualities.

METHODS

This trial included 209 patients aged 60 to 86 years undergoing tumor resection who received esketamine (Group E) or not (Group C) during and after surgery. In group E, patients were given an intravenous dose of 0.5 mg/kg of esketamine 10 minutes after induction of general anaesthesia. In addition, esketamine (2 mg/kg) in combination with sufentanil was used for PCIA during 48 hours postoperatively. On the other hand, saline was used as a substitute for esketamine in group C. Cognitive function was evaluated using neuropsychological tests and telephone interview for cognitive status-modified, and symptoms of depression were assessed using Hamilton Depression Rating Scale 17.

RESULTS

Compared to Group C, patients in Group E exhibited lower rates of depressive symptoms at 3, 7, and 90 days post-surgery (53.9% vs 67.7%, 26.3% vs 47.9%, and 13.3% vs 28.4%). Group E also showed decreased time for Trail Making Test on days 7 and 90. However, there were no significant differences in the incidence of delirium 1 to 5 days post-surgery or cognitive impairment 90 days post-surgery between the 2 groups (12.1% vs 10.9% and 8.4% vs 9.7%).

CONCLUSIONS

Intraoperative low-dose esketamine and postoperative low-dose esketamine combined with sufentanil for patient-controlled intravenous analgesia has been shown to improve postoperative analgesia, alleviate postoperative depressive symptoms, and aid in the recovery of social executive ability. However, this approach did not reduce the incidence of postoperative delirium or postoperative cognitive dysfunction.

Ketamine, Esketamine, and Arketamine: Their Mechanisms of Action and Applications in the Treatment of Depression and Alleviation of Depressive Symptoms

Research over the past years has compared the enantiomers (S)-ketamine (esketamine) and (R)-ketamine (arketamine) of the previously known racemic mixture called ketamine (R/S-ketamine). Esketamine has been found to be more potent, offering three times stronger analgesic effects and 1.5 times greater anesthetic efficacy than arketamine. It provides smoother anesthesia with fewer side effects and is widely used in clinical settings due to its neuroprotective, bronchodilatory, and antiepileptic properties. Approved by the FDA and EMA in 2019, esketamine is currently used alongside SSRIs or SNRIs for treatment-resistant depression (TRD). On the other hand, arketamine has shown potential for treating neurological disorders such as Alzheimer's, Parkinson's, and multiple sclerosis, offering possible antidepressant effects and anti-inflammatory benefits. While esketamine is already in clinical use, arketamine's future depends on further research to address its safety, efficacy, and optimal dosing. Both enantiomers hold significant clinical value, with esketamine excelling in anesthesia, and arketamine showing promise in neurological and psychiatric treatments.

Effect of esketamine combined with pregabalin on acute postsurgical pain in patients who underwent resection of spinal neoplasms: a randomized controlled trial

ABSTRACT

Moderate-to-severe acute postsurgical pain (APSP) can prolong the recovery and worsen the prognosis of patients who undergo spinal surgery. Esketamine and pregabalin may resolve APSP without causing hyperpathia or respiratory depression after surgery. However, there are other risks, such as dissociative symptoms. We designed a randomized controlled trial to investigate the effect of the combination of these 2 drugs on the incidence of APSP in patients who underwent resection of spinal neoplasms. Patients aged 18 to 65 years were randomized to receive esketamine (a bolus dose of 0.5 mg·kg -1 and an infusion dose of 0.12 mg·kg -1 ·h -1 for 48 hours after surgery) combined with oral pregabalin (75-150 mg/day, starting 2 hours before surgery and ending at 2 weeks after surgery) or an identical volume of normal saline and placebo capsules. The primary outcome was the proportion of patients with moderate-to-severe APSP (visual analog scale score ≥ 40) during the first 48 hours after surgery. Secondary outcomes included the incidence of drug-related adverse events. A total of 90 patients were randomized. The incidence of moderate-to-severe APSP in the combined group (27.3%) was lower than that in the control group (60.5%) during the first 48 hours after surgery (odds ratio = 0.25, 95% CI = 0.10-0.61; P = 0.002). The occurrence of mild dissociative symptoms was higher in the combined group than in the control group (18.2% vs 0%). In conclusion, esketamine combined with pregabalin could effectively alleviate APSP after spinal surgery, but an analgesic strategy might increase the risk of mild dissociative symptoms.

Balanced anesthesia in pigeons (Columba livia): a protocol that ensures stable vital parameters and feasibility during long surgeries in cognitive neuroscience

In neuroscience, numerous experimental procedures in animal models require surgical interventions, such as the implantation of recording electrodes or cannulas before main experiments. These surgeries can take several hours and should rely on principles that are common in the field of research and medicine. Considering the characteristics of the avian respiratory physiology, the development of a safe and replicable protocol for birds is necessary to minimize side effects of anesthetic agents, circumvent technical limitations due to the insufficient availability of patient monitoring, and to maintain stable intraoperative anesthesia. Through the consistent and responsible implementation of the three R principle of animal welfare in science ("Replace, Reduce, Refine"), we aimed to optimize experimental methods to minimize the burden on pigeons (Columba livia) during surgical procedures. Here, surgeries were conducted under balanced anesthesia and perioperative monitoring of heart rate, oxygen saturation, body temperature, and the reflex state. The protocol we developed is based on the combination of injectable and inhalative anesthetic drugs [ketamine, xylazine, and isoflurane, supported by the application of an opiate for analgesia (e.g., butorphanol, buprenorphine)]. The combination of ketamine and xylazine with a pain killer is established in veterinary medicine across a vast variety of species. Practicability was verified by survival of the animals, fast and smooth recovery quantified by clinical examination, sufficiency, and stability of anesthesia. Independent of painful stimuli like incision or drilling, or duration of surgery, vital parameters were within known physiological ranges for pigeons. Our approach provides a safe and conservative protocol for surgeries of extended duration for scientific applications as well as for veterinary medicine in pigeons which can be adapted to other bird species.

Emergency Care for High-Altitude Trekking and Climbing

Introduction: High altitude regions are characterized by harsh conditions (environmental, rough terrain, natural hazards, and limited hygiene and health care), which all may contribute to the risk of accidents/emergencies when trekking or climbing. Exposure to hypoxia, cold, wind, and solar radiation are typical features of the high altitude environment. Emergencies in these remote areas place high demands on the diagnostic and treatment skills of doctors and first-aiders. The aim of this review is to give insights on providing the best possible care for victims of emergencies at high altitude. Methods: Authors provide clinical recommendations based on their real-world experience, complemented by appropriate recent studies and internationally reputable guidelines. Results and Discussion: This review covers most of the emergencies/health issues that can occur when trekking or during high altitude climbing, that is, high altitude illnesses and hypothermia, freezing cold injuries, accidents, for example, with severe injuries due to falling, cardiovascular and respiratory illnesses, abdominal, musculoskeletal, eye, dental, and skin issues. We give a summary of current recommendations for emergency care and pain relief in case of these various incidents.

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

BACKGROUND

Use of sedatives and analgesics is associated with the occurrence of delirium in critically ill patients receiving mechanical ventilation. Dexmedetomidine reduces the occurrence of delirium but may cause hypotension, bradycardia, and insufficient sedation. This substudy aims to determine whether the combination of esketamine with dexmedetomidine can reduce the side effects and risk of delirium than dexmedetomidine alone in mechanically ventilated patients.

METHODS

This single-center, randomized, active-controlled, superiority trial will be conducted at The First Affiliated Hospital of Nanjing Medical University. A total of 134 mechanically ventilated patients will be recruited and randomized to receive either dexmedetomidine alone or esketamine combined with dexmedetomidine, until extubation or for a maximum of 14 days. The primary outcome is the occurrence of delirium, while the second outcomes include the number of delirium-free days; subtype, severity, and duration of delirium; time to first onset of delirium; total dose of vasopressors and antipsychotics; duration of mechanical ventilation; ICU and hospital length of stay (LOS); accidental extubation, re-intubation, re-admission; and mortality in the ICU at 14 and 28 days.

DISCUSSION

There is an urgent need for a new combination regimen of dexmedetomidine due to its evident side effects. The combination of esketamine and dexmedetomidine has been applied throughout the perioperative period. However, there is still a lack of evidence on the effects of this regimen on delirium in mechanically ventilated ICU patients. This substudy will evaluate the effects of the combination of esketamine and dexmedetomidine in reducing the risk of delirium for mechanically ventilated patients in ICU, thus providing evidence of this combination to improve the short-term prognosis. The study protocol has obtained approval from the Medical Ethics Committee (ID: 2022-SR-450).

TRIAL REGISTRATION

ClinicalTrials.gov: NCT05466708, registered on 20 July 2022.

Wilderness Medical Society Clinical Practice Guidelines for the Treatment of Acute Pain in Austere Environments: 2024 Update

The Wilderness Medical Society (WMS) convened an expert panel to develop evidence-based guidelines for the management of pain in austere environments. Recommendations are graded based on the quality of supporting evidence as defined by criteria put forth by the American College of Chest Physicians. This is an update of the 2014 version of the "WMS Practice Guidelines for the Treatment of Acute Pain in Remote Environments" published in Wilderness & Environmental Medicine 2014; 25:41-49.

The effect of low dose intra-articular S(+) ketamine on osteoarthritis in rats: an experimental study

BACKGROUND

This study aimed to investigate the analgesic impact of S(+)-ketamine on pain behavior and synovial inflammation in an osteoarthritis (OA) model.

METHODS

Animals were grouped as follows: OA-Saline (n = 24) and OA-Ketamine (n = 24), OA induced via intra-articular sodium monoiodoacetate (MIA); a Non-OA group (n = 24) served as the control. On the 7th day post OA induction, animals received either saline or S(+)-ketamine (0.5 mg.kg-1). Behavioral and histopathological assessments were conducted up to day 28.

RESULTS

S(+)-ketamine reduced allodynia from day 7 to 28 and hyperalgesia from day 10 to 28. It notably alleviated weight distribution deficits from day 10 until the end of the study. Significant walking improvement was observed on day 14 in S(+)-ketamine-treated rats. Starting on day 14, OA groups showed grip force decline, which was countered by S(+)-ketamine on day 21. However, S(+)-ketamine did not diminish synovial inflammation.

CONCLUSION

Low Intra-articular (IA) doses of S(+)-ketamine reduced MIA-induced OA pain but did not reverse synovial histopathological changes.

IRB APPROVAL NUMBER

23115 012030/2009-05.

Application of OFA-based ERAS for video-assisted thoracoscopic surgery in elderly patients with airway stenosis: A case report

BACKGROUND

Thoracic surgery without general anesthesia can be traced back to the First World War, and thoracic epidural block was used to complete the operation due to a large number of patients with gunshot wounds who needed emergency thoracic surgery. By reducing the intraoperative opioid dose, intraoperative and postoperative opioid-related adverse events such as respiratory depression, nausea and vomiting, delirium, hyperalgesia, and other side effects can be reduced to the benefit of patients.

METHODS

A 72-year-old male patient was admitted to the hospital with a 5-day history of multifocal pain throughout the body caused by a fall. The injury was not treated at that time, and the pain gradually increased, accompanied by cough with difficulty expelling sputum.

DIAGNOSES

Left lung contusion; traumatic pneumonia; multiple left rib fractures; left fluid pneumothorax; thyroid tumor of unknown nature, possibly malignant. Grade I tracheal stenosis; Sequelae of cerebral infarction. Because of goiter and severe tracheal compression, the patient was not intubated and received deopiated general anesthesia combined with epidural anesthesia to preserve spontaneous breathing.

OUTCOMES

At the end of the video-assisted thoracoscopic exploration, the patient was immediately conscious and returned directly to the ward 6 min later. The patient was able to move freely after surgery and eat normally within 6 h of surgery. The postoperative visual analog scale score was 2 points, and there were no anesthetic complications during the follow-up.

CONCLUSION

The opioid-free anesthesia strategy of tubeless general anesthesia, allowing spontaneous breathing combined with epidural anesthesia in elderly patients with tracheal stenosis undergoing video-assisted thoracoscopic surgery can not only avoid accidents and injuries caused by tracheal intubation and mechanical ventilation, but can also significantly reduce postoperative respiratory complications, optimize postoperative analgesia, and help achieve enhanced recovery after surgery.

The role of NMDARs in the anesthetic and antidepressant effects of ketamine

BACKGROUND

As a phencyclidine (PCP) analog, ketamine can generate rapid-onset and substantial anesthetic effects. Contrary to traditional anesthetics, ketamine is a dissociative anesthetic and can induce loss of consciousness in patients. Recently, the subanaesthetic dose of ketamine was found to produce rapid-onset and lasting antidepressant effects.

AIM

However, how different concentrations of ketamine can induce diverse actions remains unclear. Furthermore, the molecular mechanisms underlying the NMDAR-mediated anesthetic and antidepressant effects of ketamine are not fully understood.

METHOD

In this review, we have introduced ketamine and its metabolism, summarized recent advances in the molecular mechanisms underlying NMDAR inhibition in the anesthetic and antidepressant effects of ketamine, explored the possible functions of NMDAR subunits in the effects of ketamine, and discussed the future directions of ketamine-based anesthetic and antidepressant drugs.

RESULT

Both the anesthetic and antidepressant effects of ketamine were thought to be mediated by N-methyl-D-aspartate receptor (NMDAR) inhibition.

CONCLUSION

The roles of NMDARs have been extensively studied in the anaesthetic effects of ketamine. However, the roles of NMDARs in antidepressant effects of ketamine are complicated and controversial.

In Vitro Hepatotoxicity of Routinely Used Opioids and Sedative Drugs

A hepatocyte cell line was used to determine the hepatotoxicity of sedatives and opioids, as the hepatotoxicity of these drugs has not yet been well characterized. This might pose a threat, especially to critically ill patients, as they often receive high cumulative doses for daily analgosedation and often already have impaired liver function due to an underlying disease or complications during treatment. A well-established biosensor based on HepG2/C3A cells was used for the determination of the hepatotoxicity of commonly used sedatives and opioids in the intensive care setting (midazolam, propofol, s-ketamin, thiopental, fentanyl, remifentanil, and sufentanil). The incubation time was 2 × 3 days with clinically relevant (Cmax) and higher concentrations (C5× and C10×) of each drug in cell culture medium or human plasma. Afterward, we measured the cell count, vitality, lactate dehydrogenase (LDH), mitochondrial dehydrogenase activity, cytochrome P 450 1A2 (CYP1A2), and albumin synthesis. All tested substances reduced the viability of hepatocyte cells, but sufentanil and remifentanil showed more pronounced effects. The cell count was diminished by sufentanil in both the medium and plasma and by remifentanil only in plasma. Sufentanil and remifentanil also led to higher values of LDH in the cell culture supernatant. A reduction of mitochondrial dehydrogenase activity was seen with the use of midazolam and s-ketamine. Microalbumin synthesis was reduced in plasma after its incubation with higher concentrations of sufentanil and remifentanil. Remifentanil and s-ketamine reduced CYP1A2 activity, while propofol and thiopental increased it. Our findings suggest that none of the tested sedatives and opioids have pronounced hepatotoxicity. Sufentanil, remifentanil, and s-ketamine showed moderate hepatotoxic effects in vitro. These drugs should be given with caution to patients vulnerable to hepatotoxic drugs, e.g., patients with pre-existing liver disease or liver impairment as part of their underlying disease (e.g., hypoxic hepatitis or cholestatic liver dysfunction in sepsis). Further studies are indicated for this topic, which may use more complex cell culture models and global pharmacovigilance reports, addressing the limitation of the used cell model: HepG2/C3A cells have a lower metabolic capacity due to their low levels of CYP enzymes compared to primary hepatocytes. However, while the test model is suitable for parental substances, it is not for toxicity testing of metabolites.

Perioperative Ketamine and Cancer Recurrence: A Comprehensive Review

Cancer is a significant global health threat and a leading cause of death worldwide. Effective early-stage interventions, particularly surgery, can potentially cure many solid tumors. However, the risk of postoperative cancer recurrence remains high. Recent research highlights the influence of perioperative anesthetic and analgesic choices on the fate of residual cancer cells, potentially affecting recurrence risks. Among these agents, ketamine-a well-known anesthetic and analgesic-has garnered interest due to its antitumor properties, mainly through inhibiting the N-methyl-D-aspartate (NMDA) receptor found in various cancer tissues. Additionally, ketamine's potential immunomodulatory effects, given the expression of NMDA receptors on immune cells, suggest that it plays a significant role during the perioperative period. This review synthesizes current evidence on ketamine's impact on cancer cell biology, inflammation, immune modulation, and the role of the gut microbiota, proposing ketamine as a promising agent for enhancing oncological outcomes.

Substitution therapy for patients with alcohol dependence: Mechanisms of action and efficacy

New approaches for the treatment of alcohol dependence (AD) may improve patient outcomes. Substitution maintenance therapy is one of the most effective treatment options for opioid and nicotine use disorders. So far, there has been little attention to substitution therapy for the treatment of AD. Here, we explain the mechanistic foundations of alcohol substitution maintenance therapy. Alcohol has many primary targets in the brain (and other organs) and the physical interaction of ethanol molecules with these specific ethanol-sensitive sites on a variety of ionotropic receptors (e.g. GABA-A, NMDA, and nicotinic acetylcholine (nACh) receptors) and ion channels provides the rationale for substitution. As such, a variety of compounds can interact with those ethanol-sensitive sites and can thus substitute for some of the effects of alcohol. For some of these compounds, alcohol discrimination studies have shown their substitution potential. Accordingly, potential substitution treatments include agonists acting at GABA receptors such as sodium oxybate, baclofen and benzodiazepines, NMDA receptor antagonists such as ketamine and memantine, or nAChRs agonists such as varenicline. All these compounds are already approved for other indications and we present clinical evidence for these drugs in the treatment of alcohol withdrawal syndrome (AWS) and in the long-term treatment of AD, and outline future steps for their acceptance as substitution treatment in AD. Finally, we discuss the substitution approach of managed alcohol programs for the most severely affected homeless populations. Results showed that sodium oxybate is probably the closest to a substitution therapy for AD and is already approved for the treatment of AWS and in the long-term treatment of AD in some countries. In conclusion, we argue that better AD treatment can be provided if substitution maintenance treatments for alcohol are implemented at a similar scale as for opioid and nicotine use disorder.

Effective dose of propofol combined with intravenous esketamine for smooth flexible laryngeal mask airway insertion in two distinct age groups of preschool children

BACKGROUND

There is limited research on the combined use of propofol and esketamine for anesthesia induction during flexible laryngeal mask airway (FLMA) in pediatric patients, and the effective dosage of propofol for FLMA smooth insertion remains unclear. We explored the effective dose of propofol combined with intravenous esketamine for the smooth insertion of FLMA in two distinct age groups of preschool children.

METHODS

This is a prospective, observer-blind, interventional clinical study. Based on age, preschool children scheduled for elective surgery were divided into group A (aged 1-3 years) and group B (aged 3-6 years). Anesthesia induction was started with intravenous administration of esketamine (1.0 mg.kg- 1) followed by propofol administration. The FLMA was inserted 2 min after propofol administration at the target dose. The initial dose of propofol in group A and group B was 3.0 mg.kg- 1 and 2.5 mg.kg- 1, respectively. The target dose of propofol was determined with Dixon's up-and-down method, and the dosing interval of propofol was 0.5 mg.kg- 1. If there was smooth insertion of FLMA in the previous patient, the target dose of propofol for the next patient was reduced by 0.5 mg.kg- 1; otherwise, it was increased by 0.5 mg.kg- 1. The median 50% effective dose (ED50) for propofol was estimated using Dixon's up-and-down method and Probit analysis, while the 95% effective dose (ED95) was estimated through Probit analysis. Vital signs and adverse events during induction were recorded.

RESULTS

Each group included 24 pediatric patients. Using Dixon's up-and-down method, the ED50 of propofol combined with esketamine for smooth insertion of FLMA in group A was 2.67 mg.kg- 1 (95%CI: 1.63-3.72), which was higher than that in group B (2.10 mg. kg- 1, 95%CI: 1.36-2.84) (p = 0.04). Using Probit analysis, the ED50 of propofol was calculated as 2.44 (95% CI: 1.02-3.15) mg.kg- 1 in group A and 1.93 (95% CI: 1.39-2.32) mg.kg- 1 in group B. The ED95 of propofol was 3.72 (95%CI: 3.07-15.18) mg.kg- 1 in group A and 2.74 (95%CI: 2.34-5.54) mg.kg- 1 in group B. In Group B, one pediatric patient experienced laryngospasm.

CONCLUSION

The effective dose of propofol when combined with intravenous esketamine for smooth insertion of FLMA in children aged 1-3 years is 2.67 mg.kg- 1, which is higher than that in children aged 3-6 years (2.10 mg. kg- 1).

TRIAL REGISTRATION

Chinese Clinical Trial Registry Center (Registration Number: ChiCTR2100044317; Registration Date: 2021/03/16).

Safety and efficacy of low-dose esketamine in laparoscopic cholecystectomy: a prospective, double-blind randomized controlled trial

BACKGROUND

Esketamine, recognized for its analgesic, sedative, and anti-inflammatory qualities, is integral in multimodal analgesia. However, the potential opioid-sparing effects of intravenous esketamine, along with its impact on inflammatory responses, and cognitive function during laparoscopic surgery, remain unexplored.

METHODS

In this study, 90 patients scheduled for laparoscopic cholecystectomy were equally randomized into three groups: a normal saline control group (NS), a low-dose esketamine group (LS) and a high-dose esketamine group (HS). Subsequently, we monitored several parameters: hemodynamics, levels of stress and inflammatory responses, intraoperative doses of sufentanil, remifentanil, and propofol, and 24-hour postoperative sufentanil requirements. We also evaluated alterations in cognitive function, perioperative indicators, and potential adverse reactions among the three groups.

RESULTS

Compared to their levels 5 minutes prior to anesthesia (T0) and 30 minutes post-operation (T4), the NS group exhibited a more significant decrease in Mean Arterial Pressure (MAP) and Heart Rate (HR) at various time intervals: 5 minutes after the skin incision (T1), 30 minutes post-incision (T2), and at the conclusion of the operation (T3), compared to the LS and HS groups(P < 0.05). Furthermore, the NS group exhibited a greater increase in levels of adrenaline (AD), noradrenaline (NE), endothelin (ET), C-reactive protein (CRP), tumor necrosis factor-alpha (TNF-α), and interleukin-6 (IL-6) at T1, T2, and T3, more so than the other two groups(P < 0.05). 24 hours after the surgery, patients in the LS group and HS group had significantly higher Montreal Cognitive Assessment (MoCA) scores than those in the NS group(P < 0.05). The LS and HS groups required lower doses of propofol, remifentanil, and sufentanil during surgery (P < 0.05), experienced shorter postoperative recovery times, and had lower incidences of nausea, vomiting, and respiratory depression compared to the NS group (P < 0.05).

CONCLUSION

The administration of low-dose esketamine has been shown to be safe, effective, and dependable in the context of laparoscopic gallbladder surgery. It has the capacity to stabilize hemodynamic responses, ameliorate both stress and inflammatory reactions from surgery, and hastens anesthesia recovery. Furthermore, it fosters the restoration of postoperative cognitive function. Notably, when combined with nalbuphine, it exhibits opioid-sparing effects, reducing postoperative adverse outcomes.

TRIAL REGISTRATION

The trial is registered with the China Clinical Trials Registry Registration Number: ChiCTR2300067596. Retrospectively registered (date of registration: 12/01/2023).

Esketamine induces apoptosis of nasopharyngeal carcinoma cells through the PERK/CHOP pathway

Nasopharyngeal carcinoma, a malignant tumor prevalent in southeast Asia and north Africa, still lacks effective treatment. Esketamine, an N-methyl-D-aspartatic acid (NMDA) receptor (NMDAR) antagonist, is widely used in clinical anesthesia. Emerging evidence suggests that esketamine plays an important role in inhibiting tumor cell activity. However, the underlying mechanisms of esketamine on nasopharyngeal carcinoma remain unknown. In this study, we found that esketamine inhibited the proliferation and migration of nasopharyngeal carcinoma cells. Mechanically, transcriptome sequencing and subsequent verification experiments revealed that esketamine promoted the apoptosis of nasopharyngeal carcinoma cells through endoplasmic reticulum stress PERK/ATF4/CHOP signaling pathway mediated by NMDAR. Additionally, when combined with esketamine, the inhibitory effect of cisplatin on the proliferation of nasopharyngeal carcinoma cells was significantly enhanced. These findings provide new insights into future anti-nasopharyngeal carcinoma clinical strategies via targeting the NMDAR/PERK/CHOP axis alone or in combination with cisplatin.

Esketamine mitigates cognitive impairment following exposure to LPS by modulating the intestinal flora/subdiaphragmatic vagus nerve/spleen axis

INTRODUCTION

Susceptibility to secondary infection often increases after primary infection. Secondary infections can lead to more severe inflammatory injuries; however, the underlying mechanisms are not yet fully elucidated.

OBJECTIVE

To investigate whether esketamine treatment immediately after primary lipopolysaccharide (LPS) exposure could alleviate cognitive impairment caused by secondary infection.

METHODS

Mice were injected intraperitoneally (IP) with LPS (5 mg/kg) 10 days apart. Esketamine (10, 15, or 30 mg/kg) was administered IP immediately after the primary LPS injection. Splenectomy or subdiaphragmatic vagotomy (SDV) was performed 7 days before secondary LPS exposure or broad-spectrum antibiotic administration.

RESULTS

Splenomegaly was observed after the primary LPS injection on Days 3 and 10. Splenomegaly was attenuated by treatment with 30 mg/kg esketamine. Esketamine treatment prevented increased plasma proinflammatory cytokines levels and cognitive dysfunction induced by secondary LPS exposure. Mice that underwent splenectomy or SDV had lower proinflammatory cytokines levels, higher hippocampal brain-derived neurotrophic factor (BDNF) levels, and improved cognitive function 1 day after secondary infection, which was not further improved by esketamine. Fecal microbiota transplantation (FMT) from endotoxic mice treated with esketamine attenuated hippocampal BDNF downregulation and cognitive dysfunction only in pseudo germ-free (PGF) mice without splenectomy. FMT with fecal suspensions from esketamine-treated endotoxic mice abrogated splenomegaly only in PGF mice without SDV. Blocking BDNF signaling blocked esketamine's ameliorating effects on secondary LPS exposure-induced cognitive dysfunction.

CONCLUSION

The intestinal flora/subdiaphragmatic vagus nerve/spleen axis-mediated hippocampal BDNF downregulation significantly affected secondary LPS-induced systemic inflammation and cognitive dysfunction. Esketamine preserves cognitive function via this mechanism.

Comparison of the effects of esketamine, sufentanil, or lidocaine combined with propofol on tussis reflection during upper gastrointestinal endoscopy: study protocol for a randomised, two centre, three-blind, controlled trial

BACKGROUND

Tussis, which increases the incidence of airway spasm, aspiration, nausea, and vomiting, is a common complication faced during upper gastrointestinal (GI) endoscopy. However, sedatives and analgesics exhibit inhibitory actions against airway reflexes to different degrees. Our assumption is a combination of propofol and small doses of sufentanil, esketamine, or lidocaine, especially the combination of propofol and esketamine, might reduce tussis incidence.

METHOD

The study will be performed as a randomised controlled three-blind, two-centre trial. Patients undergoing upper GI endoscopy, ≥ 18 years old, with American Society of Anesthesiologists (ASA) classification I-III will be randomised to four groups: P group (single administration of propofol), P + S group (administration of propofol and sufentanil in combination), P + K group (administration of propofol and esketamine in combination), and P + L group (administration of propofol and lidocaine in combination) (N = 100 per group). The primary endpoints include the frequency of tussis, nausea and vomiting, and/or body movements observed at the insertion of the endoscope into the pharyngeal cavity or within 5 min of endoscope insertion. Secondary outcomes are recovery assessment, patients' and endoscopists' satisfaction with the procedure, MMSE scores, MET scores, sleep condition, and the number of sedation-related events. Data on sedation-related events are collected by recording of vital signs. Satisfaction parameters and mental states are collected by means of questionnaires and evaluation scales before and after the procedure and on different following days.

DISCUSSION

Esketamine can reduce tussis occurrence with good tolerability and relax the bronchus and also provides high clearance rates and low possibility of adverse reactions. We aim to demonstrate that the combination of esketamine with propofol for sedation in patients subjected to upper GI procedure is nevertheless superior to only administration of propofol or a combination of propofol with other anaesthetics, such as opioids or lidocaine.

TRIAL REGISTRATION

ClinicalTrials.gov. NCT05497492 , Registered 09 August 2022.

The effects of esketamine on blood pressure and hypotension incidence during induction of bariatric surgery: A randomized controlled trial

BACKGROUND

The prevalence of obesity is high. Bariatric surgery is an effective treatment for severe obesity; however, the induction phase of anesthesia in these patients poses a risk of hypotension. Esketamine, known for its sympathetic nervous system stimulation, may stabilize blood pressure during induction. This study aimed to investigate the effects of esketamine on blood pressure in bariatric surgery patients.

METHODS

This randomized controlled trial included 145 patients undergoing bariatric surgery. Patients were randomly assigned to receive esketamine or a control intervention during induction. Blood pressure and other vital signs were measured and compared between the 2 groups using statistical analyses.

RESULTS

Administration of esketamine increased blood pressure before intubation (T2). The incidence of hypotension was lower in the esketamine group at multiple time points during induction. Postoperatively, the esketamine group exhibited lower pain scores at 24 hours and a reduced need for rescue analgesics.

CONCLUSION

A single dose of 0.2 mg/kg esketamine during the induction phase of bariatric surgery can improve blood pressure stability and decrease the incidence of hypotension. Furthermore, it is associated with reduced postoperative pain. Future studies could explore the effects of higher esketamine doses and validate these findings in a larger and more diverse patient population.

Effect of Esketamine Added to Propofol Sedation on Desaturation and Hypotension in Bidirectional Endoscopy: A Randomized Clinical Trial

Importance

Propofol sedation is widely used for endoscopic procedures, but it poses risks of hemodynamic and respiratory depression. The addition of esketamine as an adjuvant may reduce propofol requirements and associated adverse events.

Objective

To evaluate the effects of low-dose esketamine added to propofol-based sedation on desaturation and hypotension during same-visit bidirectional endoscopy.

Design, Setting, and Participants

This multicenter, double-blind, placebo-controlled randomized clinical trial assessed patients from 3 teaching hospitals in China who were scheduled for same-visit bidirectional endoscopy between February 8 and November 30, 2022, and randomly assigned to receive esketamine or normal saline (placebo).

Interventions

After induction of sedation with 0.1 μg/kg of sufentanil and 0.5 mg/kg of propofol, patients in the esketamine group received 0.15 mg/kg of intravenous esketamine, whereas patients in the placebo group received an equivalent volume of saline. Sedation was achieved through propofol titration.

Main Outcomes and Measures

The primary outcome was the composite of desaturation and hypotension during the procedures. Secondary outcomes included desaturation, hypotension, propofol requirements, postprocedure pain and fatigue, nausea or vomiting, dizziness or headache, hallucination or nightmare, endoscopist satisfaction, and patient satisfaction.

Results

Among the 663 initially enrolled patients, 660 completed the study (median [IQR] age, 48 [36-57] years; 355 [53.8%] female), with 331 randomized to the esketamine group and 329 to the placebo group. The administration of esketamine compared with placebo significantly reduced the incidence of the composite outcome of desaturation and hypotension (8.2% vs 21.0%; difference, -12.8 percentage points; odds ratio [OR], 0.34; 95% CI, 0.21-0.54; P < .001). Additionally, esketamine led to significantly lower incidences of desaturation (OR, 0.36; 95% CI, 0.18-0.72; false discovery rate q = .01) and hypotension (OR, 0.33; 95% CI, 0.18-0.60; q < .001) and reduced propofol requirements (difference, -58.9 mg; 95% CI, -65.7 to -52.2 mg; q < .001), without significant effects on other secondary outcomes.

Conclusions and Relevance

In this randomized clinical trial of patients undergoing same-visit bidirectional endoscopy, the administration of low-dose esketamine resulted in an approximately 61% reduction in the incidence of desaturation and hypotension, accompanied by decreased propofol requirements. These findings support the use of esketamine as an adjuvant to propofol-based sedation in endoscopic procedures.

Trial Registration

Chinese Clinical Trial Registry Identifier: ChiCTR2200055938.

Evaluating the effects of S-ketamine on postoperative delirium in elderly patients following total hip or knee arthroplasty under intraspinal anesthesia: a single-center randomized, double-blind, placebo-controlled, pragmatic study protocol

Introduction

Postoperative delirium (POD) is an acute, transient brain disorder associated with decreased postoperative quality of life, dementia, neurocognitive changes, and mortality. A small number of trials have explored the role of S-ketamine in the treatment of POD due to its neuroprotective effects. Surprisingly, these trials have failed to yield supportive results. However, heterogeneity in delirium assessment methodologies, sample sizes, and outcome settings as well as deficiencies in S-ketamine use methods make the evidence provided by these studies less persuasive. Given the severe impact of POD on the health of elderly patients and the potential for S-ketamine to prevent it, we believe that designing a large sample size, and rigorous randomized controlled trial for further evaluation is necessary.

Methods

This is a single-center, randomized, double-blind, placebo-controlled, pragmatic study. Subjects undergoing total hip or knee arthroplasty will be randomized in a 1:1 ratio to intervention (n = 186) and placebo (n = 186) groups. This trial aims to explore the potential role of S-ketamine in the prevention of POD. Its primary outcome is the incidence of POD within 3 postoperative days. Secondary outcomes include the number of POD episodes, the onset and duration of POD, the severity and subtype of POD, pain scores and opioid consumption, sleep quality, clinical outcomes, and safety outcomes.

Discussion

To our knowledge, this is the first pragmatic study that proposes to use S-ketamine to prevent POD. We reviewed a large body of literature to identify potential preoperative confounding variables that may bias associations between the intervention and primary outcome. We will use advanced statistical methods to correct potential confounding variables, improving the test's power and external validity of test results. Of note, the patient population included in this trial will undergo intraspinal anesthesia. Although large, multicenter, randomized controlled studies have found no considerable difference in the effects of regional and general anesthesia on POD, patients receiving intraspinal anesthesia have less exposure to at-risk drugs, such as sevoflurane, propofol, and benzodiazepines, than patients receiving general anesthesia. At-risk drugs have been shown to negatively interfere with the neuroprotective effects of S-ketamine, which may be the reason for the failure of a large number of previous studies. There is currently a lack of randomized controlled studies evaluating S-ketamine for POD prevention, and our trial helps to fill a gap in this area.Trial registration: http://www.chictr.org.cn, identifier ChiCTR2300075796.

Safety and tolerability of esketamine in propofol based sedation for endoscopic variceal ligation with or without injection sclerotherapy: Randomized controlled trial

OBJECTIVES

Esketamine is an S (+) enantiomer of ketamine with greater potency and similar psychomimetic effects compared to racemic ketamine. We aimed to explore the safety of esketamine in different doses as an adjuvant to propofol in patients undergoing endoscopic variceal ligation (EVL) with or without injection sclerotherapy.

METHODS

One hundred patients were randomized to receive sedation with propofol 1.5 mg/kg in combination with sufentanil 0.1 μg/kg (group S), esketamine 0.2 mg/kg (group E0.2), esketamine 0.3 mg/kg (group E0.3), or esketamine 0.4 mg/kg (group E0.4) for EVL (n = 25 each). Hemodynamic and respiratory parameters were recorded during the procedure. The primary outcome was the incidence of hypotension; secondary outcomes included the incidence of desaturation, positive and negative syndrome scale (PANSS) after the procedure, pain score after the procedure, and secretion volume.

RESULTS

The incidence of hypotension was significantly lower in groups E0.2 (36%), E0.3 (20%), and E0.4 (24%) than in group S (72%). The incidence of SpO2  ≤94% was significantly lower in group E0.4 (4%) than in group S (32%). No significant intergroup difference was found in the PANSS assessment.

CONCLUSIONS

Combining 0.4 mg/kg esketamine with propofol sedation was optimal to facilitate EVL with stable hemodynamic status and better respiratory function during the procedure, without significant psychomimetic side-effects.

TRIAL REGISTRATION

Chinese Clinical Trial Registry (Trial ID: ChiCTR2100047033, http://www.chictr.org.cn/showproj.aspx?proj=127518).

Dexmedetomidine compared to low-dose ketamine better protected not only the brain but also the lungs in acute ischemic stroke

BACKGROUND

Dexmedetomidine (DEX) and low-dose ketamine (KET) present neuroprotective effects in acute ischemic stroke (AIS); however, to date, no studies have evaluated which has better protective effects not only on the brain but also lungs in AIS.

METHODS

AIS-induced Wistar rats (390 ± 30 g) were randomized after 24-h, receiving dexmedetomidine (STROKE-DEX, n = 10) or low-dose S(+)-ketamine (STROKE-KET, n = 10). After 1-h protective ventilation, perilesional brain tissue and lungs were removed for histologic and molecular biology analysis. STROKE animals (n = 5), receiving sodium thiopental but not ventilated, had brain and lungs removed for molecular biology analysis. Effects of DEX and KET mean plasma concentrations on alveolar macrophages, neutrophils, and lung endothelial cells, extracted primarily 24-h after AIS, were evaluated.

RESULTS

In perilesional brain tissue, apoptosis did not differ between groups. In STROKE-DEX, compared to STROKE-KET, tumor necrosis factor (TNF)-α and vascular cell adhesion molecule-1 (VCAM-1) expressions were reduced, but no changes in nuclear factor erythroid 2-related factor-2 (Nrf2) and super oxide dismutase (SOD)-1 were observed. In lungs, TNF-α and VCAM-1 were reduced, whereas Nrf2 and SOD-1 were increased in STROKE-DEX. In alveolar macrophages, TNF-α and inducible nitric oxide synthase (M1 macrophage phenotype) were lower and arginase and transforming growth factor-β (M2 macrophage phenotype) higher in STROKE-DEX. In lung neutrophils, CXC chemokine receptors (CXCR2 and CXCR4) were higher in STROKE-DEX. In lung endothelial cells, E-selectin and VCAM-1 were lower in STROKE-DEX.

CONCLUSIONS

In the current AIS model, dexmedetomidine compared to low-dose ketamine reduced inflammation and endothelial cell damage in both brain and lung, suggesting greater protection.

Esketamine versus Sufentanil Applied Prior to Placement of Suspension Laryngoscope

OBJECTIVE

In laryngeal microsurgery, the insertion of the suspension laryngoscope is a strong stimulus that may cause hemodynamic fluctuations and adverse cardiovascular events. The purpose of this study was to compare the effect of preemptive treatment with esketamine and sufentanil on maintaining hemodynamics and reducing the occurrence of adverse cardiovascular events during the insertion of suspension laryngoscope.

METHODS

In this double-blind randomized controlled trial, patients undergoing general anesthesia for laryngeal microsurgery were randomly assigned (1:1) to esketamine 0.5 mg kg-1 (esketamine group) and sufentanyl 0.125 μg kg-1 (sufentanil group) before inserting the laryngoscope, respectively.

RESULTS

During the insertion of suspension laryngoscope, the incidence of bradycardia (HR < 60 beats/min) was 39.3% (22/56) in esketamine group, lower than 60.0% (33/55) in sufentanil group (odds ratio [OR], 2.32 [95% CI, 1.11-5.08]; p = 0.029). The incidence of hypotension (MAP <65 mmHg) was 33.9% (19/56) in esketamine group, lower than 56.4% (31/55) in sufentanil group (odds ratio [OR], 2.52 [95% CI, 1.91-5.27]; p = 0.018). The frequency of hypotension in esketamine group was lower than that in sufentanil group (0.36 ± 0.52 vs. 0.56 ± 0.50, p = 0.035). The time-weighted average of HR dropping above 30% of baseline was smaller in esketamine group than in sufentanil group (0.52 ± 2.06 vs. 1.08 ± 2.77, p = 0.006).

CONCLUSIONS

These findings showed that compared with preemptive treatment of sufentanil (0.125 μg kg-1 ), esketamine (0.5 mg kg-1 ) was effective in reducing the incidence of cardiovascular adverse events, including bradycardia and hypotension induced by the insertion of suspension laryngoscope during the laryngeal microsurgery.

LEVEL OF EVIDENCE

2 Laryngoscope, 133:3021-3027, 2023.

Opioid Free Total Intravenous Anesthesia With Dexmedetomidine-Esketamine-Lidocaine for Patients Undergoing Lumpectomy

Background

The aim of the study was to evaluate the feasibility of the opioid-free anesthesia (OFA) technique with dexmedetomidine, esketamine, and lidocaine among patients diagnosed with benign breast mass and scheduled for lumpectomy.

Methods

We enrolled 80 female patients who were aged from 18 to 60 years, graded with American Society of Anesthesiologists physical status I or II, diagnosed with benign breast mass, and scheduled for lumpectomy. These patients were randomly treated with OFA or opioid-based anesthesia (OBA). Dexmedetomidine-esketamine-lidocaine and sufentanil-remifentanil were administered in OFA and OBA group, respectively. We mainly compared the analgesic efficacy of OFA and OBA technique, as well as intraoperative hemodynamics, the quality of recovery, and satisfaction score of patients.

Results

There was no significant difference between the two groups with regard to visual analogue scale (VAS) score at 2, 12, and 24 h after extubation. However, the time to first rescue analgesic was prolonged in OFA group than that in OFB group (6.18 ± 1.00 min vs. 7.40 ± 0.92 min, P = 0.000). Further, mean arterial pressure and heart rate at T0 (entering operating room), T1 (before anesthesia induction), T2 (immediately after intubation), T3, T4, and T5 (1, 5, and 10 min after surgical incision, respectively) were significantly higher in OFA group than that in OBA group. Incidence of hypotension and bradycardia was lower in OFA group. Consistently, fewer patients in OFA group consumed atropine (8% vs. 32%, P = 0.019) and ephedrine (5% vs. 38%, P = 0.001) compared to OBA group. Furthermore, patients in OFA group had a longer awakening time (7.14 ± 2.63 min vs. 4.54 ± 1.14 min, P = 0.000) and recovery time of orientation (11.76 ± 3.15 min vs. 6.92 ± 1.19 min, P = 0.000). Fewer patients in the OFA group experienced postoperative nausea and vomiting (PONV) (11% vs. 51%, P = 0.000) and consumed ondansetron (5% vs. 35%, P = 0.003) compared to OBA group. And patients in OFA group had a higher satisfaction score than those in OBA group (9 (8 - 9) vs. 7 (7 - 8), P = 0.000).

Conclusion

For patients undergoing lumpectomy, OFA technique with dexmedetomidine-esketamine-lidocaine showed a better postoperative analgesic efficacy, a more stable hemodynamics, and a lower incidence of PONV. However, such advantage of OFA technique should be weighed against a longer awakening time and recovery time of orientation in clinical practice.

Effect of Intraoperative Infusion of Esketamine on Quality of Postoperative Recovery in Patients Undergoing Laparoscopic Bariatric Surgery: A Randomized Controlled Trial

INTRODUCTION

This study aims to evaluate the efficacy of esketamine on postoperative recovery quality after laparoscopic bariatric surgery.

METHODS

Patients (n = 74) scheduled for laparoscopic bariatric surgery were randomly divided into two groups: the esketamine group (group E: 0.5 mg/kg/h infusion, i.e., 0.2 mL/kg/h) or the control group (group C: 0.2 mL/kg/h normal saline infusion). The infusions were stopped 20 min before the end of the procedure. The primary outcome was the Quality of Recovery-40 (QoR-40) score on postoperative day 1 (POD 1). The secondary outcomes included QoR-40 scores on PODs 2 and 7, Numeric Rating Scale (NRS) on PODs 1, 2, and 7, time to extubation, additional postoperative analgesic use, length of hospital stay, and time to first exhaust. Additonally, the safety indices were also recorded, including hemodynamic profile, perioperative anesthesia index (Ai), utilization of vasoactive drugs or urapidil, and side effects.

RESULTS

All in all, 70 of the 74 patients completed the study, 35 in each group. The difference of QoR-40 scores on POD 1 was both statistically and clinically significant [difference 7.21, 95% confidence interval (CI) 5.17, 9.25, p < 0.001]. The difference of QoR-40 on POD 2 was statistically significant but clinically insignificant (difference 4.81, 95% CI 2.69, 6.92, p < 0.001). The difference of NRS scores on POD 1 was statistically significant (difference -1.23, 95% CI -2.36, -0.10, p = 0.033). Compared with group C, group E had a lower utilization rate of phenylephrine and higher Ai values (p < 0.05). There was no statistical difference between the two groups on other measures.

CONCLUSION

Continuous ketamine infusion seems to be safe and well tolerated in laparoscopic bariatric surgery. It improved the quality of postoperative recovery and reduced pain on POD 1. In spite of the increased Ai value during the surgery, it also provided better hemodynamics with less usage of phenylephrine.

Intraoperative intravenous low-dose esketamine improves quality of early recovery after laparoscopic radical resection of colorectal cancer: A prospective, randomized controlled trial

BACKGROUND

Esketamine has higher potency, stronger receptor affinity, a stronger analgesic effect, a higher in vivo clearance rate, and a lower incidence of adverse reactions when compared to ketamine. However, there have been few ketamine studies to assess patient-centered, overall recovery outcomes from the perspective of patients with colorectal cancer.

METHODS

This was a prospective, randomized controlled trial. Ninety-two patients undergoing laparoscopic radical resection of colorectal cancer were randomly assigned to either the esketamine (K group) or non-eskatamine (C group) group. After anesthesia induction, a loading dose of 0.25 mg/kg was administered, followed by continuous infusion at a rate of 0.12 mg.kg-1.h-1 until closure of surgical incisions in the K group. In the C group, an equivalent volume of normal saline was infused. The primary outcome was quality of recovery at 24 h after surgery, as measured by the Quality of Recovery-15 (QoR-15) scale. The QoR-15 was evaluated at three timepoints: before (Tbefore), 24 h (T24h) and 72 h (T72h) after surgery.

MAIN RESULTS

A total of 88 patients completed this study. The total QoR-15 scores in K group (n = 45) were higher than in the C group (n = 43) at 24 h: 112.33 ± 8.79 vs. 103.93 ± 9.03 (P = 0.000) and at 72 h: 118.73 ± 7.82 vs. 114.79 ± 7.98 (P = 0.022). However, the differences between the two groups only had clinical significance at 24 h after surgery. Among the five dimensions of the QoR-15, physical comfort (P = 0.003), emotional state (P = 0.000), and physical independence (P = 0.000) were significantly higher at 24 h in the K group, and physical comfort (P = 0.048) was higher at 72 h in the K group.

CONCLUSIONS

This study found that intraoperative intravenous low-dose esketamine could improve the early postoperative quality of recovery in patients undergoing laparoscopic radical resection of colorectal cancer from the perspective of patients.

Efficacy and safety of perioperative application of ketamine on postoperative depression: A meta-analysis of randomized controlled studies

Ketamine, a commonly used general anesthetic, can produce rapid and sustained antidepressant effect. However, the efficacy and safety of the perioperative application of ketamine on postoperative depression remains uncertain. We performed a meta-analysis to determine the effect of perioperative intravenous administration of ketamine on postoperative depression. Randomized controlled trials comparing ketamine with placebo in patients were included. Primary outcome was postoperative depression scores. Secondary outcomes included postoperative visual analog scale (VAS) scores for pain and adverse effects associated with ketamine. Fifteen studies with 1697 patients receiving ketamine and 1462 controls were enrolled. Compared with the controls, the ketamine group showed a reduction in postoperative depression scores, by a standardized mean difference (SMD) of -0.97, 95% confidence interval [CI, -1.27, -0.66], P < 0.001, I2 = 72% on postoperative day (POD) 1; SMD-0.65, 95% CI [-1.12, -0.17], P < 0.001, I2 = 94% on POD 3; SMD-0.30, 95% CI [-0.45, -0.14], P < 0.001, I2 = 0% on POD 7; and SMD-0.25, 95% CI [-0.38, -0.11], P < 0.001, I2 = 59% over the long term. Ketamine reduced VAS pain scores on POD 1 (SMD-0.93, 95% CI [-1.58, -0.29], P = 0.005, I2 = 97%), but no significant difference was found between the two groups on PODs 3 and 7 or over the long term. However, ketamine administration distinctly increased the risk of adverse effects, including nausea and vomiting (risk ratio [RR] 1.40, 95% CI [1.12, 1.75], P = 0.003, I2 = 30%), headache (RR 2.47, 95% CI [1.41, 4.32], P = 0.002, I2 = 19%), hallucination (RR 15.35, 95% CI [6.24, 37.34], P < 0.001, I2 = 89%), and dizziness (RR 3.48, 95% CI [2.68, 4.50], P < 0.001, I2 = 89%) compared with the controls. In conclusion, perioperative application of ketamine reduces postoperative depression and pain scores with increased risk of adverse effects.

Thrifty effect of subanesthetic-dose S-ketamine on postoperative opioids and its safety and analgesic effectiveness: A prospective, triple-blind, randomized controlled, polycentric clinical trial

Aim

To investigate the thrifty effects of subanesthetic-dose S-ketamine on postoperative opioids and its safety and analgesic efficacy.

Methods

Four-hundred and twenty patients were divided into the control group (CON group), the S-ketamine 0.2 mg/kg group (ES0.2 group), and the S-ketamine 0.3 mg/kg group (ES0.3 group) randomly. Major indicators include the Visual Analogue Scale (VAS), the times of compression with analgesic pumps after surgery, and analgesic drug consumption from anesthesia induction to 48 h after surgery. Minor records include vital signs, the use of vasoactive drugs, the Ramsay scores, the occurrence of adverse events including nervous system reaction, and the patient's satisfaction with anesthesia.

Results

Compared with the CON group, VAS scores decreased in the ES0.2 and ES0.3 groups (p < 0.05). At 10 min after extubation, the VAS scores of the ES0.3 group were lower than that of the ES0.2 group (p < 0.05). The total number of compression with analgesic pumps of the ES0.3 group was lower than that of the CON group (p < 0.05). The opioid consumption after surgery of the ES0.3 group was lower than those of the CON group and the ES0.2 group (p < 0.05). The ES0.3 group's heart rate (HR) was faster but the use of vasoactive, drug consumption was less than the other two groups (p < 0.05). There were no significant differences in the incidence of postoperative adverse events and anesthetic satisfaction among the three groups.

Conclusion

Subanesthetic-dose S-ketamine at 0.2-0.3 mg/kg especially the 0.3 mg/kg in general anesthesia induction can safely and effectively reduce postoperative pain and save postoperative opioid consumption.

Evaluating efficacy and safety of sub-anesthetic dose esketamine as an adjuvant to propofol/remifentanil analgosedation and spontaneous respiration for children flexible fibreoptic bronchoscopy: a prospective, double-blinded, randomized, and placebo-controlled clinical trial

Background: Flexible fiberoptic bronchoscopy (FFB) for children is widely performed under sedation. Currently, the optimal sedation regimen remains unclear. Esketamine is an N-methyl-D-aspartic acid (NMDA) receptor antagonist, which has stronger sedative and analgesic effects and exerts less cardiorespiratory depression than other sedatives. The purpose of this study was to evaluate whether a subanesthetic dose of esketamine as an adjuvant to propofol/remifentanil and spontaneous ventilation compared with control reduces the procedural and anesthesia-related complications of FFB in children. Materials and methods: Seventy-two children ≤ 12 years of age who were scheduled for FFB were randomly assigned, in a 1:1 ratio, to the esketamine-propofol/remifentanil (Group S, n = 36) or to the propofol/remifentanil group (Group C, n = 36). All children were retained spontaneous ventilation. The primary outcome was the incidence of oxygen desaturation (respiratory depression). Perioperative hemodynamic variables, blood oxygen saturation (SPO₂), end-tidal partial pressure of carbon dioxide (PetCO₂), respiratory rate (R), and the Bispectral index (BIS), induction time, procedural time, recovery time, the time to the ward from the recovery room, consumption of propofol and remifentanil during the procedure and the appearance of adverse events, including paradoxical agitation following midazolam administration, injection pain, laryngospasm, bronchospasm, PONV, vertigo, and hallucination were also compared. Results: The incidence of oxygen desaturation was significantly lower in Group S (8.3%) compared to Group C (36.1%, p = 0.005). The perioperative hemodynamic profile including SBP, DBP, and HR were more stable in Group S than that in Group C (p < 0.05). Consumption of propofol and remifentanil was lower in Group S than in Group C (p < 0.05). Furthermore, PAED scores, cough scores and injection pain were lower in the Group S than in Group C (p < 0.05). The recovery time of Group S was slightly longer than that of Group C (p < 0.05). Nobody happened paradoxical agitation following midazolam administration, PONV, vertigo, and hallucinations in both groups (p > 0.05). Conclusion: Our findings indicate that a subanesthetic dose of esketamine as an adjuvant to propofol/remifentanil and spontaneous respiration is an effective regimen for children undergoing FFB. Our findings will provide a reference for clinical sedation practice during these procedures in children. Clinical Trail Registration: Chinese clinicaltrials.gov registry (identifier: ChiCTR2100053302).

Efficacy and Safety of a Subanesthetic Dose of Esketamine Combined with Propofol in Patients with Obesity Undergoing Painless Gastroscopy: A Prospective, Double-Blind, Randomized Controlled Trial

Purpose

Patients with obesity are more susceptible to hypoxemia. Anesthetic management for patients with obesity undergoing painless gastroscopy presents a severe challenge for anesthesiologists. Esketamine is a NMDA antagonist that has been proven to be beneficial for ameliorating respiratory depression owing to its sympathomimetic effect; however, there are no relevant reports on its use in patients with obesity. We designed a randomized controlled trial to evaluate whether esketamine can be the ideal adjuvant to propofol sedation in patients with obesity undergoing painless gastroscopy.

Patients and Methods

A total of 104 patients with obesity undergoing painless gastroscopy were randomly divided into group C (propofol+saline) and group S (propofol+esketamine 0.25 mg/kg). Anesthesia was induced by 2 mg/kg propofol with saline or esketamine. The consumption of propofol, hemodynamic parameters, duration of procedure, induction time, postoperative awakening time, and orientation recovery time were recorded. Adverse events and satisfaction scores were also recorded.

Results

Propofol consumption was 274.4±22.6 mg and 201.3±16.6 mg in groups C and S, respectively. The induction time of groups C and S were 25.4±2.3 s and 17.8±1.9 s, respectively. The postoperative awakening times of groups C and S were 6.2±1.1 min and 4.8±1.3 min, respectively. Hemodynamic parameters were more stable in group S than in group C. The incidence of adverse events such as injection pain, hypoxemia, hypotension, bradycardia, choking, and body movement were significantly lower in group S. The satisfaction scores of the endoscopist and anesthesiologist were (4.58±0.49 vs 3.71±0.83) and (4.75±0.44 vs 3.33±0.92), respectively.

Conclusion

The combination of propofol and esketamine (0.25 mg/kg) improves the safety and reduces the incidence of adverse events in patients with obesity during painless gastroscopy. Thus, this method is worthy of clinical application.

Clinical Trials Registration

ChiCTR 2200062547.

Advantages of Sedation With Remimazolam Compared to Midazolam for the Removal of Impacted Tooth in Patients With Dental Anxiety

PURPOSE

Although midazolam is commonly used to sedate patients with dental anxiety, it has shortcomings that reduce the satisfaction of patients and doctors. The aim of this study was therefore to explore the advantages of remimazolam as a sedative.

METHODS

The study design was a prospective randomized controlled trial. Patients with dental anxiety and who were to undergo impacted tooth removal were randomized into remimazolam and midazolam groups. They were sedated with remimazolam or midazolam prior to receiving nerve blocker. The predictor variable was the type of sedative, while the primary outcome variables were the onset time, awakening time, recovery time, and postoperative side effects. Secondary outcome variables were the Modified Dental Anxiety Scale score before and after surgery, patient satisfaction and comfort levels scores, and doctor satisfaction level scores. Other variables included the patient demographics and the operation time. Data were analyzed using the Student's t-test, Mann-Whitney test, χ² test, and two-way repeated measurement ANOVA test (SPSS Version 25.0).

RESULTS

A total of 83 patients were included in this study, with 42 randomized to the remimazolam group and 41 to the midazolam group. There were no significant differences between the two groups in terms of demographic features and operation time. Patients in the remimazolam group had significantly shorter onset time, awakening time, and recovery time compared to those in the midazolam group (each P < .001). Postoperative side effects were more frequent in the midazolam group (P < .001). Following surgery, the Modified Dental Anxiety Scale scores in both groups were significantly lower than prior to surgery (P < .001). Satisfaction levels scores for the patients and doctor were higher in the remimazolam group than in the midazolam group (P < .001).

CONCLUSIONS

The use of remimazolam results in faster onset, more rapid recovery, and lower incidence of postoperative side effects compared to midazolam, leading to improved satisfaction for patients and doctors. Remimazolam therefore appears to have several advantages over midazolam for the sedation of patients with dental anxiety associated with the removal of impacted teeth.

Effects of esketamine on postoperative rebound pain in patients undergoing unilateral total knee arthroplasty: a single-center, randomized, double-blind, placebo-controlled trial protocol

Introduction

Rebound pain, transient and acute postoperative pain after the disappearance of regional block anesthesia, has been a concern in recent years. Insufficient preemptive analgesia and hyperalgesia induced by regional block are the main mechanisms. At present, the evidence for the treatment of rebound pain is limited. The esketamine, as an antagonist of the N-methyl-D-aspartate receptor, has been proven to prevent hyperalgesia. Therefore, this trial aims to evaluate the impact of esketamine on postoperative rebound pain in patients undergoing total knee arthroplasty.

Methods/design

This study is a single-center, prospective, double-blind, randomized, placebo-controlled trial. Participants who plan to undergo total knee arthroplasty will be randomly assigned to the esketamine group (N = 178) and placebo group (N = 178) in a ratio of 1:1. This trial aims to evaluate the impact of esketamine on postoperative rebound pain in patients undergoing total knee arthroplasty. The primary outcome of this trial is the incidence of rebound pain within 12 h after the operation in the esketamine group and the placebo group. The secondary outcome will be to compare (1) the incidence of rebound pain 24 h after the operation; (2) the time to enter the pain cycle for the first time within 24 h after the procedure; (3) the first time of rebound pain occurred within 24 h after surgery; (4) the modified rebound pain score; (5) NRS score under rest and exercise at different time points; (6) the cumulative opioid consumption at different time points; (7) patient's prognosis and knee joint function evaluation; (8) blood glucose and cortisol concentration; (9) patient's satisfaction score; (10) adverse reactions and adverse events.

Discussion

The effect of ketamine on preventing postoperative rebound pain is contradictory and uncertain. The affinity of esketamine to the N-methyl-D-aspartate receptor is about four times higher than levo-ketamine, the analgesic effect is 3 times higher than levo-ketamine, and there are fewer adverse mental reactions. To our knowledge, there is no randomized controlled trial to verify the impact of esketamine on postoperative rebound pain in patients undergoing total knee arthroplasty. Therefore, this trial is expected to fill an important gap in relevant fields and provide novel evidence for individualized pain management.

Clinical Trial Registration

http://www.chictr.org.cn, identifier ChiCTR2300069044.

Management of Hemorrhagic Shock: Physiology Approach, Timing and Strategies

Hemorrhagic shock (HS) management is based on a timely, rapid, definitive source control of bleeding/s and on blood loss replacement. Stopping the hemorrhage from progressing from any named and visible vessel is the main stem fundamental praxis of efficacy and effectiveness and an essential, obligatory, life-saving step. Blood loss replacement serves the purpose of preventing ischemia/reperfusion toxemia and optimizing tissue oxygenation and microcirculation dynamics. The "physiological classification of HS" dictates the timely management and suits the 'titrated hypotensive resuscitation' tactics and the 'damage control surgery' strategy. In any hypotensive but not yet critical shock, the body's response to a fluid load test determines the cut-off point between compensation and progression between the time for adopting conservative treatment and preparing for surgery or rushing to the theater for rapid bleeding source control. Up to 20% of the total blood volume is given to refill the unstressed venous return volume. In any critical level of shock where, ab initio, the patient manifests signs indicating critical physiology and impending cardiac arrest or cardiovascular accident, the balance between the life-saving reflexes stretched to the maximum and the insufficient distal perfusion (blood, oxygen, and substrates) remains in a liable and delicate equilibrium, susceptible to any minimal change or interfering variable. In a cardiac arrest by exsanguination, the core of the physiological issue remains the rapid restoration of a sufficient venous return, allowing the heart to pump it back into systemic circulation either by open massage via sternotomy or anterolateral thoracotomy or spontaneously after aorta clamping in the chest or in the abdomen at the epigastrium under extracorporeal resuscitation and induced hypothermia. This is the only way to prevent ischemic damage to the brain and the heart. This is accomplishable rapidly and efficiently only by a direct approach, which is a crush laparotomy if the bleeding is coming from an abdominal +/- lower limb site or rapid sternotomy/anterolateral thoracotomy if the bleeding is coming from a chest +/- upper limbs site. Without first stopping the bleeding and refilling the heart, any further exercise is doomed to failure. Direct source control via laparotomy/thoracotomy, with the concomitant or soon following venous refilling, are the two essential, initial life-saving steps.

Low dose of esketamine combined with propofol in painless fibronchoscopy in elderly patients

To explore the effects and safety of low dose of esketamine combined with propofol in elderly patients undergoing fibronchoscopy. Eighty elderly patients who underwent painless fibronchoscopy in our hospital from June 2021 to September 2021 were recruited,and randomly divided into experimental group (esketamine 0.15mg/ kg + propofol 1mg/ kg) and control group (sufentanil 0.1 μg/ kg + propofol 1mg/ kg), with 40 cases in each group. There were significant differences in MAP, HR and SpO2 of T2, T3 and T4 between the experimental and control groups (P < .05). Besides, there were significantly differences on the trend of change between the 2 groups, with a small and relatively stable fluctuation in the experimental group (P < .05). Compared with the control group, the total dosage of propofol in the experimental group was significantly lower, and the number of vasoactive drugs, the incidence of respiratory depression and bronchospasm were significantly lower (P < .05). There was no significant difference in microscopic examination time, wake-up time, visual analogue score, and agitation, mental symptoms, increased secretion, nausea and vomiting, choking cough and laryngeal spasm during awakening period between the 2 groups. The incidence of total adverse reactions in the experimental group were strongly lower than those in control group. (P < .05). Low dose of esketamine combined with propofol can be safely used for fibronchoscopy in elderly patients, with good effects, more stable respiration and circulation, and low incidence of adverse reactions.

Evaluation of the effect of perioperative administration of S(+)-ketamine hydrochloride injection for postoperative acute pain in children: study protocol for a prospective, multicenter, randomized, open-label, parallel-group, pragmatic clinical trial

Background

Inadequate postoperative pain management increases the risk of adverse events after the surgery and aggressive perioperative pain prevention has both short-term and long-term benefits. S(+)-ketamine is an N-methyl-D-aspartic acid (NMDA) receptor antagonist with a strong analgesic effect and can significantly relieve postoperative acute pain and reduce opioid consumption. However, for children, it still needs to be confirmed by large sample clinical studies.

Methods

This is a pragmatic, randomized controlled trial which will evaluate the effect of perioperative administration of S(+)-ketamine hydrochloride injection for postoperative acute pain in children in a pragmatic clinical setting. A total of 3000 children (≤17 years old) undergoing surgery will be included in this protocol. Subjects will be randomized 2:1 to either receive S(+)-ketamine hydrochloride injection or conventional therapy without S(+)-ketamine during the entire perioperative period. The primary endpoints are the area under the receiver operating characteristic (ROC) curve of Face Legs Activity Cry and Consolability (FLACC, 0–7 years old) scale score or Numerical Rating Scale (NRS, 8–17 years old) score within 48 h after surgery, and the consumption of opioids within 48 h after surgery. The secondary endpoints include the time of first use of rescue analgesics after surgery, rescue analgesia rate within 48 h after surgery, anesthesia recovery time, incidence of emergency delirium (for 0-7 years old), changes of anxiety and depression scale scores at 48 h after surgery (for 8-17 years old), incidence of intraoperative adverse events (AEs), and incidence of postoperative AEs and pharmacoeconomic indicators. AEs and serious AEs were recorded to evaluate safety.

Discussion

This trial will be the first pragmatic clinical trial to prospectively assess the effect of perioperative administration of S(+)-ketamine hydrochloride injection for postoperative acute pain in children, which is of great significance to the continuous optimization of clinical anesthesia and analgesia programs for children.

Trial registration

This trial was registered in the U.S. National Institutes of Health ClinicalTrials.gov database (http://clinicaltrials.gov; Registration number: NCT04834427). Registered on 8 April 2021.

Sedative effect and safety of different doses of S-ketamine in combination with propofol during gastro-duodenoscopy in school-aged children: a prospective, randomized study

Background

Propofol combined with opioids can reduce the dosage of propofol and improve the safety of endoscopy. However, there are few studies on propofol combined with S-ketamine in children undergoing gastro-duodenoscopy. We aim to determine the sedative effect and safety of different doses of S-ketamine in combination with propofol in school-aged children undergoing gastro-duodenoscopy.

Methods

This is a prospective, randomized trial. Totally, 120 school-aged children who underwent gastro-duodenoscopy were randomly allocated into Group P, Group S0.3, Group S0.5 and Group S0.7. During induction, children in Group P, Group S0.3, Group S0.5 and Group S0.7 received 0, 0.3 mg.kg−1, 0.5 mg.kg−1 and 0.7 mg.kg−1 S-ketamine, respectively, following 3 mg.kg−1 propofol injection. During gastro-duodenoscopy, 1 mg.kg−1 of propofol was added according to the condition of the children and the BIS (bispectral index) value. The primary outcome was smooth placement rate of the first endoscope insertion. The secondary outcome was the times of additional propofol, the total amount of propofol, adverse events, recovery time, length of PACU (post anesthesia care unit) stay and endoscopist satisfaction.

Results

The smooth placement rate of the first endoscope insertion in Group P, Group S0.3 and Group S0.5 was significantly lower than that in Group S0.7 (16.70%, 34.50%, 50.00% vs. 83.30%, respectively, P < 0.001). The times of additional propofol in Group S0.3 (P = 0.018), Group S0.5 (P = 0.014) and Group S0.7 (P = 0.001) were significantly less than Group P. The total amount of propofol in Group S0.7 was significantly less than Group P (P < 0.001). The incidence of intraoperative hypotension in Group S0.5 and Group S0.7 was low. Group S0.7 had significantly higher incidence of postoperative dizziness (P = 0.003), longer PACU stay (P = 0.018) and higher endoscopist satisfaction (P = 0.001) than Group P. There was no difference in the recovery time among groups.

Conclusion

S-ketamine (0.7 mg.kg−1) in combination with propofol can provide satisfactory sedative effect and reduce the dosage of propofol in school-aged children undergoing gastro-duodenoscopy, but there are higher incidence of postoperative dizziness and longer PACU stay.

Effects of Remimazolam Combined with Esketamine Anesthesia on Circulatory and Respiratory Function during Painless Gastroenteroscopy

Objective

To investigate the effect of applying remimazolam combined with esketamine for anesthesia in painless gastroenteroscopy on patients' circulatory and respiratory function.

Method

In this study, 106 patients who had undergone painless gastroenteroscopy in Xinjiang Production and Construction Corps (XPCC) Hospital between July 2021 and January 2022 were selected as study subjects, which were grouped according to the anesthetic drugs used in the surgery and divided into control group (n = 53 cases) and observation group (n = 53 cases), while those who were anesthetized with propofol + sufentanil during the operation were the control group and those who were anesthetized with remimazolam + esketamine were the observation group. To compare the induction time of anesthesia, patient awakening and recovery time of orientation, circulatory and respiratory function, intraoperative adverse effects, and postoperative complications in the two study groups.

Results

There was no statistical difference in induction of anesthesia, patient awakening, and recovery time of orientation between the two groups (P > 0.05) and no statistical difference in postoperative complications (P > 0.05). The observation group had a better occurrence of local pain at the injection site, circulatory and respiratory function of patients after anesthesia, and intraoperative adverse reactions than the control group (P < 0.05).

Conclusion

Remimazolam combined with esketamine anesthesia has the same advantages of rapid awakening compared with propofol anesthesia. Moreover, it has fewer side effects on patients' circulatory and respiratory functions with fewer adverse effects, as a suitable anesthetic method for painless gastroenteroscopy.

Effective dose of propofol combined with a low-dose esketamine for gastroscopy in elderly patients: A dose finding study using dixon’s up-and-down method

Objective: This study aimed to determine the optimal dose of propofol combined with esketamine to inhibit the response to gastroscope insertion in elderly patients.

Methods: This is a prospective, non-controlled, non-randomized, single-center study. Elderly patients aged 65–80 years were enrolled in the study with the American society of anesthesiologists (ASA) physical status I or II undergoing elective gastroscopy. All patients were administered propofol after an intravenous esketamine at the dosage of 0.3 mg/kg 30 s, the subsequent dose of propofol was determined by the response of the previous patient to gastroscope insertion (choking, body movement, etc.) using Dixon’s up-and-down method. The initial dose of propofol administered to the first elderly patient was 3.0 mg/kg, and the standard ratio of propofol dose in adjacent patients was 0.9. At least six crossover points were obtained before the conclusion of the study. By using Probit analysis the median effective dose (ED₅₀), 95% effective dose (ED₉₅), and the corresponding 95% confidence interval (CI) for propofol were determined.

Results: The study continued until we obtained seven crossover points and 32 elderly patients (17 males and 15 females) were collected. The ED₅₀ of propofol combined with esketamine inhibiting response to gastroscope insertion in elderly patients were found to be 1.479 mg/kg (95% CI 1.331–1.592 mg/kg), and ED₉₅ was found to be 1.738 mg/kg (95% CI 1.614–2.487 mg/kg).

Conclusion: According to the present study, propofol combined with 0.3 mg/kg esketamine is safe and effective for elderly patients undergoing gastroscopy. The ED₅₀ and ED₉₅ doses of propofol inhibiting response to gastroscope insertion in elderly patients when combined with 0.3 mg/kg esketamine were 1.479 and 1.738 mg/kg, respectively, without apparent adverse effects.

S-ketamine administration in pregnant mice induces ADHD- and depression-like behaviors in offspring mice

BACKGROUND

Anesthesia and psychotropic drugs in pregnant women may cause long-term effects on the brain development of unborn babies. The authors set out to investigate the neurotoxicity of S-ketamine, which possesses anesthetic and antidepressant effects and may cause attention deficit hyperactivity disorder (ADHD)- and depression-like behaviors in offspring mice.

METHODS

Pregnant mice were administered with low-, medium-, and high-dose S-ketamine (15, 30, and 60 mg/kg) by intraperitoneal injection for 5 days from gestational day 14-18. At 21 days after birth, an elevated plus-maze test, fear conditioning, open field test, and forced swimming test were used to assess ADHD- and depression-like behaviors. Neuronal amount, glial activation, synaptic function indicated by ki67, and inhibitory presynaptic proteins revealed by GAD2 in the hippocampus, amygdala, habenula nucleus, and lateral hypothalamus (LHA) were determined by immunofluorescence assay.

RESULTS

All the pregnant mice exposed to high-dose S-ketamine administration had miscarriage after the first injection. Both low-dose and medium-dose S-ketamine administration significantly increased the open-arm time and attenuated frozen time in the fear conditioning, which indicates impulsivity and memory dysfunction-like behaviors. Medium-dose S-ketamine administration reduced locomotor activity in the open field and increased immobility time in the forced swimming test, indicating depression-like behaviors. Changes in astrocytic activation, synaptic dysfunction, and decreased inhibitory presynaptic proteins were found in the hippocampus, amygdala, and habenula nucleus.

CONCLUSIONS

These results demonstrate that S-ketamine may lead to detrimental effects, including ADHD-and depression-like behaviors in offspring mice. More studies should be promoted to determine the neurotoxicity of S-ketamine in the developing brain.

Advantages of ketamine in pediatric anesthesia

Although ketamine is primarily used for induction and maintenance of general anesthesia, it also presents sedative, amnestic, anesthetics, analgesic, antihyperalgesia, neuroprotective, anti-inflammatory, immunomodulant, and antidepressant effects. Its unique pharmacodynamics and pharmacokinetic properties allow the use of ketamine in various clinical settings including sedation, ambulatory anesthesia, and intensive care practices. It has also adopted to manage acute and chronic pain management. Clinically, ketamine produces dissociative sedation, analgesia, and amnesia while maintaining laryngeal reflexes, with respiratory and cardiovascular stability. Notably, it does not cause respiratory depression, maintaining both the hypercapnic reflex and the residual functional capacity with a moderate bronchodilation effect. In the pediatric population, ketamine can be administered through practically all routes, making it an advantageous drug for the sedation required setting such as placement of difficult vascular access and in uncooperative and oppositional children. Consequently, ketamine is indicated in prehospital induction of anesthesia, induction of anesthesia in potentially hemodynamic unstable patients, and in patients at risk of bronchospasm. Even more, ketamine does not increase intracranial pressure, and it can be safely used also in patients with traumatic brain injuries. This article is aimed to provide a brief and practical summary of the role of ketamine in the pediatric field.