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

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

Multiple Exposures to Sevoflurane General Anesthesia During Pregnancy Inhibit CaMKII/CREB Axis by Downregulating HCN2 to Induce an Autism-Like Phenotype in Offspring Mice.

The objective of this investigation was to examine the impact of multiple exposures to general anesthesia (GA) with sevoflurane on the offspring of pregnant mice, as well as to elucidate the underlying mechanism. Neurodevelopmental assessments, including various reflexes and behavioral tests, were conducted on the offspring in the GA group to evaluate neuronal cell development. Furthermore, neonatal mouse neuronal cells were isolated and transfected with a high-expression CREB vector (pcDNA3.1-CREB), followed by treatment with sevoflurane (0.72 mol/L), ZD7288 (50 µmol/L), and KN-62 (10 µmol/L), or a combination of these compounds. The expression of relevant genes was then analyzed using qRT-PCR and western blot techniques. In comparison to the sham group, neonatal mice in the GA group exhibited significantly prolonged latencies in surface righting reflex, geotaxis test, and air righting reflex. Furthermore, there was a notable deceleration in the development of body weight and tail in the GA group. These mice also displayed impairments in social ability, reduced reciprocal social interaction behaviors, diminished learning capacity, and heightened levels of anxious behaviors. Additionally, synaptic trigger malfunction was observed, along with decreased production of c-Fos and neurotrophic factors. Sevoflurane was found to notably decrease cellular c-Fos and neurotrophic factor production, as well as the expression of HCN2 and CaMKII/CREB-related proteins. The inhibitory effects of sevoflurane on HCN2 or CaMKII channels were similar to those observed with ZD7288 or KN-62 inhibition. However, overexpression of CREB mitigated the impact of sevoflurane on neuronal cells. Repetitive exposure to sevoflurane general anesthesia while pregnant suppresses the CaMKII/CREB pathway, leading to the development of autism-like characteristics in offspring mice through the reduction of HCN2 expression.

Short-term inhalation of xenon during anesthesia for prevention of postoperative delirium in elderly patients undergoing laparoscopic radical colectomy: study protocol for a randomized controlled clinical trial.

BACKGROUND: Postoperative delirium (POD) is a common complication that is characterized by acute onset of impaired cognitive function and is associated with an increased mortality, a prolonged duration of hospital stay, and additional healthcare expenditures. The incidence of POD in elderly patients undergoing laparoscopic radical colectomy ranges from 8 to 54%. Xenon has been shown to provide neuroprotection in various neural injury models, but the clinical researches assessing the preventive effect of xenon inhalation on the occurrence of POD obtained controversial findings. This study aims to investigate the effects of a short xenon inhalation on the occurrence of POD in elderly patients undergoing laparoscopic radical colectomy. METHODS/DESIGN: This is a prospective, randomized, controlled trial and 132 patients aged 65-80 years and scheduled for laparoscopic radical colectomy will be enrolled. The participants will be randomly assigned to either the control group or the xenon group (n = 66 in each group). The primary outcome will be the incidence of POD in the first 5 days after surgery. Secondary outcomes will include the subtype, severity, and duration of POD, postoperative pain score, Pittsburgh Sleep Quality Index (PQSI), perioperative non-delirium complications, and economic parameters. Additionally, the study will investigate the activation of microglial cells, expression of inflammatory factors in colon tissues, plasma inflammatory factors, and neurochemical markers. DISCUSSION: Elderly patients undergoing laparoscopic radical colectomy are at a high risk of POD, with delayed postoperative recovery and increased healthcare costs. The primary objective of this study is to determine the preventive effect of a short xenon inhalation on the occurrence of POD in these patients. TRIAL REGISTRATION: Chinese Clinical Trial Registry ChiCTR2300076666. Registered on October 16, 2023, http://www.chictr.org.cn .

Nitrous oxide myelopathy: a case series.

AIMS: To describe the clinical features and outcomes of patients with myelopathy and neuropathy due to recreationally inhaled nitrous oxide. METHODS: We identified patients presenting with nitrous oxide-associated myelopathy from an electronic database of all discharges in a large tertiary hospital between 2016 and 2023. Demographics, clinical features and the results of investigations were recorded. The primary outcome was modified Rankin Scale score (mRS) at least 3 months after hospital discharge where available. RESULTS: There were 12 patients identified, six women, mean (SD) age 27.5 (5.1) years, range 19-47 years. The most common symptoms were numbness, weakness and mental state changes. Four patients used large amounts of inhaled nitrous oxide and also took over-the-counter vitamin B12 supplements. The median (range) hospital length of stay was 8.5 (2-56) days. Functional independence at last assessment (median [range] of 3 [1-34] months after discharge) was achieved in nine of the patients, with three requiring ongoing support for activities of daily living (mRS ≥3). CONCLUSION: Nitrous oxide abuse and its neurological complications are an important public health issue. Clinicians should be aware that some patients who use large amounts of nitrous oxide may self-supplement vitamin B12.

Comparison of the Influence of Intraoperative Use of Sevoflurane and Isoflurane on Postoperative Nausea, Vomiting, and Cough.

INTRODUCTION: Postoperative nausea, vomiting, and cough are the most common adverse effects of general anesthesia resulting in high discomfort to the patient resulting in uneasiness during the recovery period. This study aimed to compare the influence of intraoperative use of sevoflurane and isoflurane on postoperative nausea, vomiting, and cough. MATERIALS AND METHODS: After approval from the institutional ethical committee, this quantitative observational institutional study was conducted on all patients aged between 18 and 65 years undergoing surgery under general anesthesia at KMC Hospital, Mangalore. Patients were allocated into the sevoflurane group or isoflurane group. RESULTS: All demographic parameters such as age, sex, American Society of Anesthesiologists physical status, and duration were comparable (P > 0.05). The sevoflurane group had higher number of patients (11 [14.86%]) with postoperative nausea at 0 h as compared isoflurane group (7 [9.45%]). Two patients in the isoflurane group reported postoperative vomiting at 0 h, whereas no patient in the sevoflurane group reported vomiting. For cough, a statistically significant correlation was seen between the two groups (P = 0.000) with majority of patients in the isoflurane group, i.e., 50 (67.6%) patients reporting cough at 0 h while only 15 (20.3%) reported cough in the sevoflurane group. CONCLUSION: Sevoflurane was found to be better than isoflurane in terms of postoperative nausea vomiting and cough immediately after emergence in our study. Isoflurane cause the emergence of cough whereas no significant difference in nausea and vomiting was observed in both groups.

Résumé Introduction:Les nausées, vomissements et toux postopératoires sont les effets indésirables les plus courants de l'anesthésie générale, entraînant un inconfort élevé pour le patient, entraînant un malaise pendant la période de récupération. Cette étude visait à comparer l'influence del'utilisation peropératoire du sévoflurane et de l'isoflurane sur les nausées, vomissements et toux postopératoires.Méthode:Après approbation du comité d'éthique institutionnel, cette étude institutionnelle observationnelle quantitative a été menée sur tous les patients âgés de 18 à 65 ans subissant une intervention chirurgicale sous anesthésie générale à l'hôpital KMC de Mangalore. Les patients ont été répartis dans le groupe sévoflurane ou le groupe isoflurane.Résultats:Tous les paramètres démographiques comme l'âge, le sexe, l'ASA PS et la durée étaient comparables. ( P > 0,05) Le groupe sévoflurane avait un nombre plus élevé de patients [11 (14,86 %)] présentant des nausées postopératoires à 0 heure par rapport au groupe isoflurane [7 (9,45 %)]. 2 patients du groupe Isoflurane ont signalé des vomissements postopératoires à 0 heure alors qu'aucun patient du groupe Sévoflurane n'a signalé de vomissements. Pour la toux, une corrélation statistiquement significative a été observée entre les deux groupes ( P = 0,000) avec une majorité de patients dansle groupe isoflurane, c'est-à-dire 50 (67,6 %) patients signalant une toux à 0 heure, alors que seulement 15 (20,3 %) ont signalé une toux dans le groupe sévoflurane.Conclusion:Le sévoflurane s'est révélé meilleur que l'isoflurane en termes de nausées, vomissements et toux postopératoires immédiatement après l'émergence dans notre étude. L'isoflurane provoque une toux d'émergence alors qu'aucune différence significative en termes de nausées et de vomissements n'a été observée dans les deux groupes.

Volatile Anesthetic Use Versus Total Intravenous Anesthesia for Patients Undergoing Heart Valve Surgery: A Nationwide Population-Based Study.

BACKGROUND: Many studies have suggested that volatile anesthetic use may improve postoperative outcomes after cardiac surgery compared to total intravenous anesthesia (TIVA) owing to its potential cardioprotective effect. However, the results were inconclusive, and few studies have included patients undergoing heart valve surgery. METHODS: This nationwide population-based study included all adult patients who underwent heart valve surgery between 2010 and 2019 in Korea based on data from a health insurance claim database. Patients were divided based on the use of volatile anesthetics: the volatile anesthetics or TIVA groups. After stabilized inverse probability of treatment weighting (IPTW), the association between the use of volatile anesthetics and the risk of cumulative 1-year all-cause mortality (the primary outcome) and cumulative long-term (beyond 1 year) mortality were assessed using Cox regression analysis. RESULTS: Of the 30,755 patients included in this study, the overall incidence of 1-year mortality was 8.5%. After stabilized IPTW, the risk of cumulative 1-year mortality did not differ in the volatile anesthetics group compared to the TIVA group (hazard ratio, 0.98; 95% confidence interval, 0.90-1.07; P = .602), nor did the risk of cumulative long-term mortality (hazard ratio, 0.98; 95% confidence interval, 0.93-1.04; P = .579) at a median (interquartile range) follow-up duration of 4.8 (2.6-7.6) years. CONCLUSIONS: Compared with TIVA, volatile anesthetic use was not associated with reduced postoperative mortality risk in patients undergoing heart valve surgery. Our findings indicate that the use of volatile anesthetics does not have a significant impact on mortality after heart valve surgery. Therefore, the choice of anesthesia type can be based on the anesthesiologists' or institutional preference and experience.

Subsequent maternal sleep deprivation aggravates cognitive impairment by modulating hippocampal neuroinflammatory responses and synaptic function in maternal isoflurane-exposed offspring mice.

INTRODUCTION: Pregnant women may need to undergo non-obstetric surgery under general anesthesia owing to medical needs, and pregnant women frequently experience sleep disturbances during late gestation. Preclinical studies demonstrated that maternal isoflurane exposure (MISO) or maternal sleep deprivation (MSD) contributed to cognitive impairments in offspring. Research studies in mice have revealed that SD can aggravate isoflurane-induced cognitive deficits. However, it remains unclear whether MSD aggravates MISO-induced cognitive deficits in offspring. The purpose of this research was to explore the combined effects of MSD and MISO on offspring cognitive function and the role of neuroinflammation and synaptic function in the process of MSD + MISO. METHODS: Pregnant mice were exposed to 1.4% isoflurane by inhalation for 4 h on gestational day (GD) 14. Dams were then subjected to SD for 6 h (12:00-18:00 h) during GD15-21. At 3 months of age, the offspring mice were subjected to the Morris water maze test to assess cognitive function. Then the levels of inflammatory and anti-inflammatory markers and synaptic function-related proteins were assessed using molecular biology methods. RESULTS: The results of this study demonstrated that MISO led to cognitive dysfunction, an effect that was aggravated by MSD. In addition, MSD exacerbated the maternal isoflurane inhalation, leading to an enhancement in the expression levels of interleukin (IL)-1ß, IL-6, and tumor necrosis factor-alpha and a reduction in the hippocampal levels of IL-10, synaptophysin, post-synaptic density-95, growth-associated protein-43, and brain-derived neurotrophic factor. CONCLUSION: Our findings revealed that MSD aggravated the cognitive deficits induced by MISO in male offspring mice, and these results were associated with neuroinflammation and alternations in synaptic function.

The Impact of the Combined Effect of Inhalation Anesthetics and Iron Dextran on Rats' Systemic Toxicity.

Disruption of any stage of iron homeostasis, including uptake, utilization, efflux, and storage, can cause progressive damage to peripheral organs. The health hazards associated with occupational exposure to inhalation anesthetics (IA) in combination with chronic iron overload are not well documented. This study aimed to investigate changes in the concentration of essential metals in the peripheral organs of rats after iron overload in combination with IA. The aim was also to determine how iron overload in combination with IA affects tissue metal homeostasis, hepcidin-ferritin levels, and MMP levels according to physiological, functional, and tissue features. According to the obtained results, iron accumulation was most pronounced in the liver (19×), spleen (6.7×), lungs (3.1×), and kidneys (2.5×) compared to control. Iron accumulation is associated with elevated heavy metal levels and impaired essential metal concentrations due to oxidative stress (OS). Notably, the use of IA increases the iron overload toxicity, especially after Isoflurane exposure. The results show that the regulation of iron homeostasis is based on the interaction of hepcidin, ferritin, and other proteins regulated by inflammation, OS, free iron levels, erythropoiesis, and hypoxia. Long-term exposure to IA and iron leads to the development of numerous adaptation mechanisms in response to toxicity, OS, and inflammation. These adaptive mechanisms of iron regulation lead to the inhibition of MMP activity and reduction of oxidative stress, protecting the organism from possible damage.

Effects of different anesthetic regimens on postoperative cognitive function of elderly patients undergoing thoracic surgery: a double-blinded randomized controlled trial.

OBJECTIVE: Postoperative cognitive dysfunction (POCD) is a serious surgical complication. We assessed the different POCD incidences between anesthesia using sevoflurane and sevoflurane combined with dexmedetomidine, with propofol-based sedation in elderly patients who underwent a thoracic surgical procedure. METHODS: A total of 90 patients aged 65 to 80 years old who underwent a thoracic surgical procedure at our hospital and 15 nonsurgical participants as controls, were enrolled in this study. Patients were divided in a randomized 1:1:1 ratio into 3 groups. All participants were randomized into a trial with three anesthesia groups (P, PS, PSD) or a control group (C) of healthy matches. All trial groups received distinct anesthetic combinations during surgery, while controls mirrored patient criteria.Group P (propofol and remifentanil were maintained during the surgery), Group PS (propofol, remifentanil, and sevoflurane were maintained during the surgery), and Group PSD (propofol, remifentanil, sevoflurane, and dexmedetomidine were maintained during the surgery).All participants were rated using a series of cognitive assessment scales before and three days after surgery. All participants were interviewed over the telephone, 7 days, 30 days, and 90 days postoperatively. RESULTS: POCD incidences in the PSD (combined anesthetization with propofol, sevoflurane, and dexmedetomidine) group was significantly lower than that in the PS (combined anesthetization with propofol and sevoflurane) group, 1 day post-surgery (10.0% vs. 40.0%, P = 0.008), and the results were consistent at 3 days post-surgery. When the patients were assessed 7 days, 30 days, and 90 days postoperatively, there was no significant difference in POCD incidence among the three groups. Multivariate logistic regression analysis of POCD one day after surgery showed that education level was negatively correlated with incidence of POCD (P = 0.018) and single lung ventilation time was positively correlated with incidence of POCD (P = 0.001). CONCLUSION: For elderly patients who underwent a thoracic surgical procedure, dexmedetomidine sedation shows an obvious advantage on improving short-term POCD incidence, which is caused by sevoflurane.

Effect of volatile versus propofol anaesthesia on major complications and mortality after cardiac surgery: a multicentre randomised trial.

BACKGROUND: The comparative effectiveness of volatile anaesthesia and total intravenous anaesthesia (TIVA) in terms of patient outcomes after cardiac surgery remains a topic of debate. METHODS: Multicentre randomised trial in 16 tertiary hospitals in China. Adult patients undergoing elective cardiac surgery were randomised in a 1:1 ratio to receive volatile anaesthesia (sevoflurane or desflurane) or propofol-based TIVA. The primary outcome was a composite of predefined major complications during hospitalisation and mortality 30 days after surgery. RESULTS: Of the 3123 randomised patients, 3083 (98.7%; mean age 55 yr; 1419 [46.0%] women) were included in the modified intention-to-treat analysis. The composite primary outcome was met by a similar number of patients in both groups (volatile group: 517 of 1531 (33.8%) patients vs TIVA group: 515 of 1552 (33.2%) patients; relative risk 1.02 [0.92-1.12]; P=0.76; adjusted odds ratio 1.05 [0.90-1.22]; P=0.57). Secondary outcomes including 6-month and 1-yr mortality, duration of mechanical ventilation, length of ICU and hospital stay, and healthcare costs, were also similar for the two groups. CONCLUSIONS: Among adults undergoing cardiac surgery, we found no difference in the clinical effectiveness of volatile anaesthesia and propofol-based TIVA. CLINICAL TRIAL REGISTRATION: Chinese Clinical Trial Registry (ChiCTR-IOR-17013578).

[Nitrous oxide as a party drug]. / Partydroge Lachgas.

In recent years, reports of health problems associated with nitrous oxide consumption have significantly increased. In Germany, nitrous oxide (N2O) is easily available in cartridges without legal restrictions. The main reason for its popularity in the party scene are the euphoric, psychedelic effects of the gas. In addition to severe and sometimes irreversible health problems associated with long-term use of nitrous oxide, e.g., anemia and nerve damage, life-threatening or fatal consequences of acute nitrous oxide consumption can also occur: accidents under the influence of nitrous oxide, pneumothorax, pneumopericardium and shock due to an explosive increase in airway pressure when inhaled directly from the cartridge. But the most common cause of severe complications is asphyxia as the gas is usually inhaled pure from large balloons and without oxygen. The resulting hypoxia during use may be perpetuated by the diffusion hypoxia that occurs during the reoxygenation period. Nitrous oxide as a cause in accidental or intoxication events is usually not detectable but can only be identified as a trigger based on the patient's history or the circumstances. Acute medical treatment is symptomatic.

Isoflurane anesthesia and sleep deprivation trigger delayed and selective sleep alterations.

Isoflurane anesthesia (IA) partially compensates NREM sleep (NREMS) and not REM sleep (REMS) requirement, eliciting post-anesthetic REMS rebound. Sleep deprivation triggers compensatory NREMS rebounds and REMS rebounds during recovery sleep as a result of the body's homeostatic mechanisms. A combination of sleep deprivation and isoflurane anesthesia is common in clinical settings, especially prior to surgeries. This study investigates the effects of pre-anesthetic sleep deprivation on post-anesthetic sleep-wake architecture. The effects of isoflurane exposure (90 min) alone were compared with the effects of isoflurane exposure preceded by experimental sleep deprivation (6 h, gentle handling) on recovery sleep in adult mice by studying the architecture of post-anesthetic sleep for 3 consecutive post-anesthetic days. Effects of isoflurane anesthesia on recovery sleep developed only during the first dark period after anesthesia, the active phase in mice. During this time, mice irrespective of preceding sleep pressure, showed NREMS and REMS rebound and decreased wakefulness during recovery sleep. Additionally, sleep deprivation prior to isoflurane treatment caused a persistent reduction of theta power during post-anesthetic REMS at least for 3 post-anesthetic days. We showed that isoflurane causes NREMS rebound during recovery sleep which suggests that isoflurane may not fully compensate for natural NREMS. The study also reveals that isoflurane exposure preceded by sleep deprivation caused a persistent disruption of REMS quality. We suggest that preoperative sleep deprivation may impair postoperative recovery through lasting disruption in sleep quality.

Environmental impact of anesthetic drugs.

PURPOSE OF REVIEW: The environmental impact of anesthesia far exceeds that of other medical specialties due to our use of inhaled anesthetic agents (which are potent greenhouse gases) and many intravenous medications. RECENT FINDINGS: Calls for reducing the carbon footprint of anesthesia are ubiquitous in the anesthesia societies of developed nations and are appearing in proposed changes for hospital accreditation and funding in the United States. The body of research on atmospheric, land and water impacts of anesthetic pharmaceuticals is growing and generally reinforces existing recommendations to reduce the greenhouse gas emissions of anesthesia care. SUMMARY: The environmental impact of anesthesia care should factor into our clinical decisions. The onus is on clinicians to safely care for our patients in ways that contribute the least harm to the environment. Intravenous anesthesia and regional techniques have less environmental impact than the use of inhaled agents; efforts to reduce and properly dispose of pharmaceutical waste are central to reducing environmental burden; desflurane should not be used; nitrous oxide should be avoided except where clinically necessary; central nitrous pipelines should be abandoned; low fresh gas flows should be utilized whenever inhaled agents are used.

Isoflurane-induced neuroinflammation and NKCC1/KCC2 dysregulation result in long-term cognitive disorder in neonatal mice.

BACKGROUND: The inhalational anesthetic isoflurane is commonly utilized in clinical practice, particularly in the field of pediatric anesthesia. Research has demonstrated its capacity to induce neuroinflammation and long-term behavioral disorders; however, the underlying mechanism remains unclear [1]. The cation-chloride cotransporters Na+-K+-2Cl--1 (NKCC1) and K+-2Cl--2 (KCC2) play a pivotal role in regulating neuronal responses to gamma-aminobutyric acid (GABA) [2]. Imbalances in NKCC1/KCC2 can disrupt GABA neurotransmission, potentially leading to neural circuit hyperexcitability and reduced inhibition following neonatal exposure to anesthesia [3]. Therefore, this study postulates that anesthetics have the potential to dysregulate NKCC1 and/or KCC2 during brain development. METHODS: We administered 1.5% isoflurane anesthesia to neonatal rats for a duration of 4 h at postnatal day 7 (PND7). Anxiety levels were assessed using the open field test at PND28, while cognitive function was evaluated using the Morris water maze test between PND31 and PND34. Protein levels of NKCC1, KCC2, BDNF, and phosphorylated ERK (P-ERK) in the hippocampus were measured through Western blotting analysis. Pro-inflammatory cytokines IL-1ß, IL-6, and TNF-α were quantified using ELISA. RESULTS: We observed a decrease in locomotion trajectories within the central region and a significantly shorter total distance in the ISO group compared to CON pups, indicating that isoflurane induces anxiety-like behavior. In the Morris water maze (MWM) test, rats exposed to isoflurane exhibited prolonged escape latency onto the platform. Additionally, isoflurane administration resulted in reduced time spent crossing in the MWM experiment at PND34, suggesting long-term impairment of memory function. Furthermore, we found that isoflurane triggered activation of pro-inflammatory cytokines IL-1ß, IL-6, and TNF-α; downregulated KCC2/BDNF/P-ERK expression; and increased the NKCC1/KCC2 ratio in the hippocampus of PND7 rats. Bumetadine (NKCC1 specific inhibitors) reversed cognitive damage and effective disorder induced by isoflurane in neonatal rats by inhibiting TNF-α activation, normalizing IL-6 and IL-1ß levels, restoring KCC2 expression levels as well as BDNF and ERK signaling pathways. Based on these findings, it can be speculated that BDNF, P-ERK, IL-1ß, IL-6 and TNF - α may act downstream of the NKCC1/KCC2 pathway. CONCLUSIONS: Our findings provide evidence that isoflurane administration in neonatal rats leads to persistent cognitive deficits through dysregulation of the Cation-Chloride Cotransporters NKCC1 and KCC2, BDNF, p-ERK proteins, as well as neuroinflammatory processes.

Perspectives on sustainable practices in the use of nitrous oxide for labour analgesia: A patient and staff survey.

BACKGROUND: Climate change has emerged as the single biggest global health threat of the twenty-first century. Nitrous oxide accounts for the largest carbon footprint amongst our use of anaesthetic gas. It is a potent greenhouse gas possessing a global warming potential of approximately 265 times that of carbon dioxide. Despite recent curtailment of its use, it remains extensively employed as an analgesic for women in labour. OBJECTIVES: Assessment of the opinions of post-natal women and staff on nitrous oxide use and to investigate whether knowledge of its environmental harm would influence their choice of labour analgesia. DESIGN: Postnatal women and healthcare staff were invited to participate in a survey of nitrous oxide use as a labour analgesic and knowledge of its effect of the environment. SETTING: A single-centre study in a major obstetric tertiary referral centre in Ireland in 2021. MAIN OUTCOME MEASURES: To evaluate the awareness and perceptions of postnatal women and staff regarding the environmental impact of nitrous oxide and if it would affect their decision to use it in the future. RESULTS: One hundred postnatal women and 50 healthcare staff completed the survey. One hundred and six post-natal women were invited to complete the survey, resulting in a response rate of 94%. Knowledge of nitrous oxide's environmental impact was low. After receiving information, 46% of patients were more inclined to seek epidural or request it earlier (54%) to limit their nitrous oxide use, while 51% would choose an alternative analgesia to avoid nitrous oxide altogether. Overwhelmingly, 99% believed they had the right to know about these harmful effects when choosing an analgesic option. CONCLUSIONS: Patients should be informed of the environmental impact of nitrous oxide antenatally, empowering them to make informed decision on a climate friendly analgesic option if they wish.

Comparison between propofol and total inhalational anaesthesia on cardiovascular outcomes following on-pump cardiac surgery in higher-risk patients: a randomised controlled pilot and feasibility study.

OBJECTIVES: Myocardial revascularisation and cardiopulmonary bypass (CPB) can cause ischaemia-reperfusion injury, leading to myocardial and other end-organ damage. Volatile anaesthetics protect the myocardium in experimental studies. However, there is uncertainty about whether this translates into clinical benefits because of the coadministration of propofol and its detrimental effects, restricting myocardial protective processes. METHODS: In this single-blinded, parallel-group randomised controlled feasibility trial, higher-risk patients undergoing elective coronary artery bypass graft (CABG) surgery with an additive European System for Cardiac Operative Risk Evaluation ≥5 were randomised to receive either propofol or total inhalational anaesthesia as single agents for maintenance of anaesthesia. The primary outcome was the feasibility of recruiting and randomising 50 patients across two cardiac surgical centres, and secondary outcomes included the feasibility of collecting the planned perioperative data, clinically relevant outcomes and assessments of effective patient identification, screening and recruitment. RESULTS: All 50 patients were recruited within 11 months in two centres, allowing for a 13-month hiatus in recruitment due to the COVID-19 pandemic. Overall, 50/108 (46%) of eligible patients were recruited. One patient withdrew before surgery and one patient did not undergo surgery. All but one completed in-hospital and 30-day follow-up. CONCLUSIONS: It is feasible to recruit and randomise higher-risk patients undergoing CABG surgery to a study comparing total inhalational and propofol anaesthesia in a timely manner and with high acceptance and completion rates. TRIAL REGISTRATION NUMBER: NCT04039854.

Hypotension after general anaesthesia induction using remimazolam or propofol in geriatric patients undergoing sevoflurane anaesthesia with remifentanil: a single-centre, double-blind, randomised controlled trial.

BACKGROUND: The occurrence of hypotension after induction of general anaesthesia is common in geriatric patients, and should be prevented to minimise perioperative complications. Compared with propofol, remimazolam potentially has a lower incidence of hypotension. This study aimed to compare the incidence of hypotension after general anaesthesia induction with remimazolam or propofol in geriatric patients. METHODS: This single-centre, double-blind, randomised trial enrolled 90 patients aged ≥80 yr who received general anaesthesia for scheduled surgery. Patients were randomised to receive remimazolam (12 mg kg-1 h-1) or propofol (0.025 mg kg-1 s-1) for anaesthesia induction, with remifentanil and sevoflurane. The presence or absence of hypertension on the ward served as the stratification factor. The incidence of hypotension after the induction of general anaesthesia, defined as a noninvasive mean arterial pressure of <65 mm Hg measured every minute from initiation of drug administration to 3 min after tracheal intubation, was the primary outcome. Subgroup analysis was performed for the primary outcome using preoperative ward hypertension, clinical frailty scale, Charlson Comorbidity Index, and age. RESULTS: Three subjects were excluded before drug administration, and 87 subjects were included in the analysis. The incidence of hypotension was 72.1% (31/43) and 72.7% (32/44) with remimazolam or propofol, respectively. No statistically significant differences (adjusted odds ratio, 0.96; 95% confidence interval, 0.37-2.46; P=0.93) were observed between groups. Subgroup analysis revealed no significant differences between groups. CONCLUSIONS: Compared with propofol, remimazolam did not reduce the incidence of hypotension after general anaesthesia induction in patients aged ≥80 yr. CLINICAL TRIAL REGISTRATION: UMIN000042587.