Volatile Anesthetics Research Articles

Identification of Prefrontal Cortex and Amygdala Expressed Genes Associated With Sevoflurane Anesthesia on Non-human Primate.

Clinical trials and animal studies have indicated that long-term use or multiple administrations of anesthesia may lead to fine motor impairment in the developing brain. Most studies on anesthesia-induced neurotoxicity have focused on the hippocampus and prefrontal cortex (PFC); however, the role of other vital encephalic regions, such as the amygdala, is still unclear. Herein, we focused on sevoflurane, the most commonly used volatile anesthetic in infants, and performed a transcriptional analysis of the PFC and amygdala of macaques after multiple exposures to the anesthetic by RNA sequencing. The overall, overlapping, and encephalic region-specific transcriptional patterns were separately analyzed to reveal their functions and differentially expressed gene sets that were influenced by sevoflurane. Specifically, functional, protein–protein interaction, neighbor gene network, and gene set enrichment analyses were performed. Further, we built the basic molecular feature of the amygdala by comparing it to the PFC. In comparison with the amygdala’s changing pattern following sevoflurane exposure, functional annotations of the PFC were more enriched in glial cell-related biological functions than in neuron and synapsis development. Taken together, transcriptional studies and bioinformatics analyses allow for an improved understanding of the primate PFC and amygdala.

PHARMACOGENETIC ASPECTS OF THE USE OF PERIOPERATIVE DRUGS IN PEDIATRICS. Review

Relevance. It is known that in children the frequency of perioperative critical events due to the introduction of drugs is more than 5%. For example fentanyl, which is used as an adjunct to surgical anesthesia, is a major factor in increasing the number of deaths from opioid overdoses. Among the areas of reducing the frequency of severe adverse reactions to perioperative drugs - taking into account the pharmacogenetic variations of the patient.
 Objective is to consider current data on pharmacogenetic aspects of pharmacokinetics and pharmacodynamics of perioperative drugs.
 Methods. Analysis of the data presented in PubMed by keywords "pharmacogenetics", "general anesthetics", "analgesics", "muscle relaxants", "children". Search depth – 7 years (2014-2020), with a retrospective deepening of some positions until 2002.
 Results. The pharmacogenetic aspects of the pharmacokinetics of perioperative drugs are related to the genes of the enzymes that metabolize them and their transporters. Current data on the prevalence of polymorphic alleles of CYP2C9 genes (provides metabolism of nonsteroidal anti-inflammatory and anticonvulsant drugs) and CYP2D6 (metabolizes opioids, antidepressants, antiemetics) in Europe and, in particular, in Ukraine were presented. Thus, the inactive allele CYP2C19 * 2 was found in 13%, while the allele of increased activity CYP2C19 * 17 - in 25% of the population of Ukraine; allele with lost CYP2D6 function (CYP2D6 * 4) - in 18.6% of Ukrainians. Homozygotes with CYP2C9 * 3 polymorphism metabolize nonsteroidal anti-inflammatory drugs much more slowly than wild-type carriers, which may lead to their accumulation and side effects. The analgesic effect of codeine occurs only after it is metabolized in the liver by CYP2D6 to morphine. Respiratory depression, apnea and death may occur in patients with excessive metabolic rate even after a single dose of codeine; however, was noted the ineffectiveness of ondansetron due to a decrease in its concentration in the blood in thesepatients. Concomitant use of midazolam and fentanyl may prolong the effect of fentanyl by competing metabolism of midazolam by the hepatic enzyme CYP3A4, especially in patients with low metabolism. Plasma butyrylcholinesterase deficiency reduces succinylcholine inactivation in 1 in 1,500 people. Changing the genotype of uridine diphosphate glycosyltransferase causes increased glucuronidation of morphine, which may lead to a decrease in its effectiveness. As an example of pharmacogenetic changes in pharmacodynamics can be considered malignant hyperthermia, which occurs due to exposure to volatile anesthetics and depolarizing muscle relaxants in mutations in the RYR1 gene. Carriers of the minor allele (G) of the 5HT2A rs6313 gene require less propofol and 40% less time to start induction of anesthesia.
 Conclusions. The efficacy and safety of perioperative drugs are largely related to the pharmacogenetic aspects of their pharmacokinetics, especially mutations in genes of enzymes of the metabolism. Mutations in the genes of volatile anesthetic receptors and depolarizing muscle relaxants when their used cause a risk of malignant hyperthermia. The application of pharmacogenetics is the need to titrate drugs that have significant variability of action depending on the genotype. It is advisable to avoid the use of drugs with a high risk of pharmacogenetic reactions, if other alternative drugs are available.

Effect of equipotent doses of propofol and sevoflurane on endoplasmic reticulum stress during breast cancer surgery.

Numerous studies suggest that intravenous propofol is superior to inhaled volatile anesthetic. This study compared the changes in the endoplasmic reticulum (ER) stress of cancer cells and lymphocytes after propofol- and sevoflurane-based anesthesia during breast cancer surgery. We randomized 53 patients undergoing breast cancer surgery to propofol (n = 28) and sevoflurane (n = 25) anesthesia groups. Blood samples were obtained immediately before inducing anesthesia, and 1 and 24 h postoperatively. Human breast cancer cell lines were cultured and treated with patient plasma, and the frequency of C/EBP homologous protein (CHOP) on the cancer cell lines and lymphocytes was measured. The neutrophil-to-lymphocyte ratio in plasma was evaluated in both groups. The CHOP expression on breast cancer cell lines did not differ between the groups (P = 0.108), although it decreased significantly over time (P = 0.027). The CHOP expression on lymphocytes was comparable between the groups (P = 0.485), and was the neutrophil-to-lymphocyte ratio (P = 0.501). Propofol-based anesthesia did not induce greater ER stress than sevoflurane-based anesthesia during breast cancer surgery. The ER stress of cancer cells did not differ according to the type of anesthesia during breast cancer surgery.

Volatile versus Propofol General Anesthesia and Long-term Survival after Breast Cancer Surgery: A National Registry Retrospective Cohort Study.

Several retrospective studies using administrative or single-center data have failed to show any difference between general anesthesia using propofol versus inhaled volatiles on long-term survival after breast cancer surgery. Although randomized controlled trials are ongoing, validated data from national clinical registries may advance the reliability of existing knowledge. Data on breast cancer surgery performed under general anesthesia between 2013 and 2019 from the Swedish PeriOperative Registry and the National Quality Registry for Breast Cancer were record-linked. Overall survival was compared between patients receiving propofol and patients receiving inhaled volatile for anesthesia maintenance. Of 18,674 subjects, 13,873 patients (74.3%) received propofol and 4,801 (25.7%) received an inhaled volatile for general anesthesia maintenance. The two cohorts differed in most respects. Patients receiving inhaled volatile were older (67 yr vs. 65 yr), sicker (888 [19.0%] American Society of Anesthesiologists status 3 to 5 vs. 1,742 [12.8%]), and the breast cancer to be more advanced. Median follow-up was 33 months (interquartile range, 19 to 48). In the full, unmatched cohort, there was a statistically significantly higher overall survival among patients receiving propofol (13,489 of 13,873 [97.2%]) versus inhaled volatile (4,039 of 4,801 [84.1%]; hazard ratio, 0.80; 95% CI, 0.70 to 0.90; P < 0.001). After 1:1 propensity score matching (4,658 matched pairs), there was no statistically significant difference in overall survival (propofol 4,284 of 4,658 [92.0%]) versus inhaled volatile (4,288 of 4,658 [92.1%]; hazard ratio, 0.98; 95% CI, 0.85 to 1.13; P = 0.756). Among patients undergoing breast cancer surgery under general anesthesia, no association was observed between the choice of propofol or an inhaled volatile maintenance and overall survival.

Effect of Volatile Anesthesia Versus Total Intravenous Anesthesia on Postoperative Pulmonary Complications in Patients Undergoing Cardiac Surgery: A Randomized Clinical Trial

The purpose of this study was to evaluate the effect of volatile anesthesia and propofol-based total intravenous anesthesia (TIVA) on postoperative pulmonary complications (PPCs) among patients undergoing cardiac surgery. Parallel-group, randomized controlled trial. Single-center tertiary care hospital. Five hundred twenty-four patients undergoing cardiac surgery with cardiopulmonary bypass. The patients were assigned randomly (1:1) to receive anesthesia maintenance with a volatile anesthetic (sevoflurane or desflurane) or propofol-based TIVA. The primary outcome was a composite of postoperative pulmonary complications within the first 7 postoperative days. The PPCs occurred in 118 of 262 patients (45.0%) in the volatile anesthesia group compared with 105 of 262 patients (40.1%) in the propofol-based intravenous anesthesia group (relative risk: 1.17 [95% CI 0.96-1.42], p=0.123). There were no significant differences in the severity of PPCs within 7 days postoperatively, the occurrence and severity grade of PPCs within 30 days, the incidence of hypoxia, and 30-day mortality. In adult patients undergoing cardiac surgery with cardiopulmonary bypass, general anesthesia with a volatile anesthetic compared with propofol-based TIVA had not reduced pulmonary complications within the first 7 days after surgery.

Maintenance of Anesthesia in Paranasal Endoscopic Sinus Surgery: Sevoflurane or Isoflurane? Which One Is Better?

Background: Volatile anesthetics are the most prevalent drugs in maintenance of anesthetics and their platelet effects are compared. Functional endoscopic sinus surgery is known as a common type of nasal surgery. One of the most problems in this surgery is the blood filling up the nose or obscuring the lens of the camera as well as the surgeon’ view. It can cause the procedure take longer or accidently damage surrounding structures such as eye and brain. Objectives: This study was performed for comparing the effectiveness of isoflurane and sevoflurane on the bleeding rate of functional endoscopic sinus surgery (FESS). Methods: This study is a triple blind study on elective functional endoscopic sinus surgery. A total of 23 patients were assigned to each group, and after informed consent, isoflurane was administered for one and sevoflurane for another group. The evaluation was performed by an anesthetic assistant who arrived at the end of study plus the grade score. The surgeon also evaluated the extent of bleeding during the surgery. The results were assessed by Spearman and Mann-Whitney tests. Results: The average age of isoflurane group (43.3) was older than the sevoflurane group (33.96). Systolic blood pressure was also higher in the isoflurane group (141) than in the sevoflurane group (133.6). Conclusions: There was no difference between the bleeding rate and grade score of surgeons. There was no difference between the systolic blood pressure and the bleeding rate either.

An Update on Postoperative Cognitive Dysfunction Following Cardiac Surgery.

Postoperative cognitive dysfunction is extremely prevalent following cardiac surgery. The increasing patient age and comorbidity profile increases their susceptibility to cognitive impairment. The underlying pathophysiological mechanisms leading to cognitive impairment are not clearly elucidated. Using the contemporary literature (2015–present), this narrative review has three aims. Firstly, to provide an overview of postoperative cognitive impairment. Secondly, to analyse the predominant pathophysiological mechanisms leading to cognitive dysfunction following cardiac surgery such as inflammation, cerebral hypoperfusion, cerebral microemboli, glycaemic control and anaesthesia induced neurotoxicity. Lastly, to assess the current therapeutic strategies of interest to address these pathophysiological mechanisms, including the administration of dexamethasone, the prevention of prolonged cerebral desaturations and the monitoring of cerebral perfusion using near-infrared spectroscopy, surgical management strategies to reduce the neurological effects of microemboli, intraoperative glycaemic control strategies, the effect of volatile vs. intravenous anaesthesia, and the efficacy of dexmedetomidine.

Anaesthetic Management of Patient with Hypertrophy Obstructive Cardiomyopathy Posted for Elective Caesarean

Introduction: Dynamic valvular insufficiency and LVOT blockage are also possible outcomes of hypertrophic obstructive cardiomyopathy (HOCM). Furthermore, attempting to replace an inadequate mitral valve surgically can result in iatrogenic LVOT blockage. In the general population, it affects one out of every 500 adults, with a male to female ratio of 2:1. Among the general population, the prevalence is around 0.2 percent, and the incidence in pregnant women is around 0.1–0.5 percent. Case Report: 21 year old female patient presented with 9 months of amenorrhea posted for elective lower segment caesarean section. Her previous documents revealed that she was a diagnosed case of hypertrophic obstructive cardiomyopathy during her last pregnancy 1 year ago. History of previous surgery that is induced abortion at two and half months of gestation age a year back operated under spinal anaesthesia. ECG showed ST elevation present in V2 , V3, V4 , V5 leads and features of left ventricular hypertrophy (LVH) , Her echocardiography report revealed features of hypertrophic obstructive cardiomyopathy with severe LVOT obstruction. Left ventricular ejection fraction (LVEF) was 20-25%. Conclusion: HOCM is normally well tolerated during pregnancy, although those who have had previous symptoms or arrhythmias may experience an exacerbation of symptoms. The majority of these people, on the other hand, can be effectively controlled medically. This case report showed that patients with HOCM can be safely managed under general anaesthesia with muscle relaxants and inhalational volatile anaesthetics, as well as an erector spinae block for analgesia

Analysis of Volatile Anesthetic-Induced Organ Protection in Simultaneous Pancreas-Kidney Transplantation.

Background: Despite recent advances in surgical procedures and immunosuppressive regimes, early pancreatic graft dysfunction, mainly specified as ischemia–reperfusion injury (IRI)—Remains a common cause of pancreas graft failure with potentially worse outcomes in simultaneous pancreas-kidney transplantation (SPKT). Anesthetic conditioning is a widely described strategy to attenuate IRI and facilitate graft protection. Here, we investigate the effects of different volatile anesthetics (VAs) on early IRI-associated posttransplant clinical outcomes as well as graft function and outcome in SPKT recipients. Methods: Medical data of 105 patients undergoing SPKT between 1998–2018 were retrospectively analyzed and stratified according to the used VAs. The primary study endpoint was the association and effect of VAs on pancreas allograft failure following SPKT; secondary endpoint analyses included “IRI- associated posttransplant clinical outcome” as well as long-term graft function and outcome. Additionally, peak serum levels of C-reactive protein (CRP) and lipase during the first 72 h after SPKT were determined and used as further markers for “pancreatic IRI” and graft injury. Typical clinicopathological characteristics and postoperative outcomes such as early graft outcome and long-term function were analyzed. Results: Of the 105 included patients in this study three VAs were used: isoflurane (n = 58 patients; 55%), sevoflurane (n = 22 patients; 21%), and desflurane (n = 25 patients, 24%). Donor and recipient characteristics were comparable between both groups. Early graft loss within 3 months (24% versus 5% versus 8%, p = 0.04) as well as IRI-associated postoperative clinical complications (pancreatitis: 21% versus 5% versus 5%, p = 0.04; vascular thrombosis: 13% versus 0% versus 5%; p = 0.09) occurred more frequently in the Isoflurane group compared with the sevoflurane and desflurane groups. Anesthesia with sevoflurane resulted in the lowest serum peak levels of lipase and CRP during the first 3 days after transplantation, followed by desflurane and isoflurane (p = 0.039 and p = 0.001, respectively). There was no difference with regard to 10-year pancreas graft survival as well as endocrine/metabolic function among all three VA groups. Multivariate analysis revealed the choice of VAs as an independent prognostic factor for graft failure three months after SPKT (HR 0.38, 95%CI: 0.17–0.84; p = 0.029). Conclusions: In our study, sevoflurane and desflurane were associated with significantly increased early graft survival as well as decreased IRI-associated post-transplant clinical outcomes when compared with the isoflurane group and should be the focus of future clinical studies evaluating the positive effects of different VA agents in patients receiving SPKT.

Metformin alleviates prolonged isoflurane inhalation induced cognitive decline via reducing neuroinflammation in adult mice

With the widespread use of volatile anesthetic agents in the prolonged sedation for COVID-19 pneumonia and ARDS, there is an urgent need to investigate the effects and treatments of lengthy low-concentration inhaled anesthetics exposure on cognitive function in adults. Previous studies showed that general anesthetics dose- and exposure length-dependently induced neuroinflammatory response and cognitive decline in neonatal and aging animals. The anti-diabetes drug metformin has anti-neuroinflammation effects by modulating microglial polarization and inhibiting astrocyte activation. In this study, we demonstrated that the inhalation of 1.3% isoflurane (a sub-minimal alveolar concentration, sub-MAC) for 6 h impaired recognition of novel objects from Day 1 to Day3 in adult mice. Prolonged sub-MAC isoflurane exposure also triggered typically reactive microglia and A1-like astrocytes in the hippocampus of adult mice on Day 3 after anesthesia. In addition, prolonged isoflurane inhalation switched microglia into a proinflammatory M1 phenotype characterized by elevated CD68 and iNOS as well as decreased arginase-1 and IL-10. Metformin pretreatment before anesthesia enhanced cognitive performance in the novel object test. The positive cellular modifications promoted by metformin pretreatment included the inhibition of reactive microglia and A1-like astrocytes and the polarization of microglia into M2 phenotype in the hippocampus of adult mice. In conclusion, prolonged sub-MAC isoflurane exposure triggered significant hippocampal neuroinflammation and cognitive decline in adult mice which can be alleviated by metformin pretreatment via inhibiting reactive microglia and A1-like astrocytes and promoting microglia polarization toward anti-inflammatory phenotype in the hippocampus.

Variants in ASPH cause exertional heat illness and are associated with malignant hyperthermia susceptibility

Exertional heat illness (EHI) and malignant hyperthermia (MH) are life threatening conditions associated with muscle breakdown in the setting of triggering factors including volatile anesthetics, exercise, and high environmental temperature. To identify new genetic variants that predispose to EHI and/or MH, we performed genomic sequencing on a cohort with EHI/MH and/or abnormal caffeine-halothane contracture test. In five individuals, we identified rare, pathogenic heterozygous variants in ASPH, a gene encoding junctin, a regulator of excitation-contraction coupling. We validated the pathogenicity of these variants using orthogonal pre-clinical models, CRISPR-edited C2C12 myotubes and transgenic zebrafish. In total, we demonstrate that ASPH variants represent a new cause of EHI and MH susceptibility.

A Comparison of Emergence Behaviour and Cost Effectiveness in Tonsillectomy Patients Undergoing General Anaesthesia with Desflurane versus Sevoflurane

Background: It has been seen that volatile anaesthetics agents which are speedily eliminated with minimal breakdown should facilitate faster recovery from general anaesthesia. As compared to isoflurane-based anaesthesia, both sevoflurane and desflurane have shorter emergence times due to rapid induction and elimination.&#x0D; Aim: The aim of this study is to compare and analyse the superiority of both agents, with regards to the emergence and recovery from anaesthesia, intraoperative hemodynamics, postoperative side effects and estimate the average quantity and cost-benefit of both volatile agents consumed.&#x0D; Methods: Total of 100 cases above the age of 6 years undergoing tonsillectomy surgeries of ASA grade 1&amp; 2 was included. Patients were allocated into two groups by computer-generated numbers. Group S: Anaesthesia maintained with 50/50 mixture of nitrous oxide/oxygen and sevoflurane. Group D: Anaesthesia maintained with 50/50 mixture of nitrous oxide/oxygen and desflurane. The parameters recorded were compared between the two groups using the unpaired t-test for continuous variables and P≤0.005 is deemed significant.&#x0D; Results: There was no significant hemodynamic difference intraoperatively between sevoflurane and desflurane except in the desflurane group, heart rate was higher. Recovery was faster and better in Group D.&#x0D; Conclusion: Postoperative recovery was better and faster and postoperative complication was lower in the desflurane group. Though the total cost of desflurane group was higher compared to sevoflurane but the use of desflurane can be justified with lesser complication, faster emergence from anaesthesia, faster shifting from PACU, lesser hospital stays, lower chance of nosocomial infection and lower cost of hospital stay.

Pre-operative exercise and pyrexia as modifying factors in malignant hyperthermia (MH)

Malignant hyperthermia (MH) is a life-threatening reaction triggered by volatile anesthetics and succinylcholine. MH is caused by mutations in the skeletal muscle ryanodine receptor (RYR1) gene, as is rhabdomyolysis triggered by exertion and/or pyrexia. The discrepancy between the prevalence of risk genotypes and actual MH incidence remains unexplained. We investigated the role of pre-operative exercise and pyrexia as potential MH modifying factors. We included cases from 5 MH referral centers with 1) clinical features suggestive of MH, 2) confirmation of MH susceptibility on Contracture Testing (IVCT or CHCT) and/or RYR1 genetic testing, and a history of 3) strenuous exercise within 72 h and/or pyrexia >37.5 °C prior to the triggering anesthetic. Characteristics of MH-triggering agents, surgery and succinylcholine use were collected. We identified 41 cases with general anesthesias resulting in an MH event (GA+MH, n = 41) within 72 h of strenuous exercise and/or pyrexia. We also identified previous general anesthesias without MH events (GA-MH, n = 51) in the index cases and their MH susceptible relatives. Apart from pre-operative exercise and/or pyrexia, trauma and acute abdomen as surgery indications, emergency surgery and succinylcholine use were also more common with GA+MH events. These observations suggest a link between pre-operative exercise, pyrexia and MH.

Isoflurane inhibition of endocytosis is an anesthetic mechanism of action

The mechanisms of volatile anesthetic action remain among the most perplexing mysteries of medicine. Across phylogeny, volatile anesthetics selectively inhibit mitochondrial complex I, and they also depress presynaptic excitatory signaling. To explore how these effects are linked, we studied isoflurane effects on presynaptic vesicle cycling and ATP levels in hippocampal cultured neurons from wild-type and complex Imutant (Ndufs4(KO)) mice. To bypass complex I, we measured isoflurane effects on anesthetic sensitivity in mice expressing NADH dehydrogenase (NDi1). Endocytosis in physiologic concentrations of glucose was delayed by effective behavioral concentrations of isoflurane in both wild-type (τ [unexposed] 44.8± 24.2 s;τ [exposed] 116.1± 28.1 s; p<0.01) and Ndufs4(KO) cultures (τ [unexposed] 67.6± 16.0 s;τ [exposed] 128.4± 42.9 s; p= 0.028). Increasing glucose, to enhance glycolysis and increase ATP production, led to maintenance of both ATP levels and endocytosis (τ [unexposed] 28.0± 14.4;τ [exposed] 38.2± 5.7; reducing glucose worsened ATP levels and depressed endocytosis (τ [unexposed] 85.4± 69.3; τ [exposed]>1,000; p<0.001). The block in recycling occurred at the level of reuptake of synaptic vesicles into the presynaptic cell. Expression of NDi1 in wild-type mice caused behavioral resistance to isoflurane for tail clamp response (EC50 Ndi1(-) 1.27%± 0.14%; Ndi1(+) 1.55%± 0.13%) and halothane (EC50 Ndi1(-) 1.20%± 0.11%; Ndi1(+) 1.46%± 0.10%); expression of NDi1 in neurons improved hippocampal function, alleviated inhibition of presynaptic recycling, and increased ATP levels during isoflurane exposure. The clear alignment of cell culture data to invivo phenotypes of both isoflurane-sensitive and -resistant mice indicates that inhibition of mitochondrial complex I is a primary mechanism of action of volatile anesthetics.

Reduction of greenhouse gases emission through the use of tiletamine and zolazepam

Isoflurane is an anaesthetic gas widely used in both human and veterinary medicine. All currently used volatile anaesthetics are ozone-depleting halogenated compounds. The use of total intravenous anaesthesia (TIVA) allows to induce the effect of general anaesthesia by administering drugs only intravenously without the use of anaesthetic gases. This allows you to create a protocol that is safe not only for the patient, but also for doctors and the environment. However, so far, no anaesthetic protocol based on induction of anaesthesia with tiletamine-zolazepam without the need to maintain anaesthesia with anaesthetic gas has been developed. Our study showed that the use of this combination of drugs for induction does not require the use of additional isoflurane to maintain anaesthesia. Thanks to Dixon's up-and-down method we proved that with the induction of anaesthesia with tiletamine-zolazepam at a dose of 5 mg/kg the use of isoflurane is not needed to maintain anaesthesia in minimally invasive surgical procedures. Until now, this dose has been recommended by the producer for more diagnostic than surgical procedures or for induction of general anaesthesia. The maintenance was required with anaesthetic gas or administration of another dose of the tiletamine-zolazepam. The results obtained in this study will allow for a significant reduction in the consumption of isoflurane, a gas co-responsible for the deepening of the greenhouse effect, having a negative impact on patients and surgeons. These results are certainly the first step to achieving a well-balanced and safe TIVA-based anaesthetic protocol using tiletamine-zolazepam, the obvious goal of which will be to maximize both the safety of the patient, people involved in surgical procedures, and the environment itself. Being aware of the problem of the greenhouse effect, we are committed to reducing the consumption of anaesthetic gases by replacing them with infusion agents.

An Entropy-Based Prospective Randomized Controlled Trial to Evaluate the Analgesic and Hypnotic Effects of Equipotent Doses of Sevoflurane and Isoflurane in Patients Presenting for Spine Surgeries.

Objectives Minimal alveolar concentration (MAC) of anesthetic agents has been considered a suitable measure of the potency of inhalational anesthetics. Furthermore, it is assumed that equi-MAC concentrations of different anesthetic agents have a similar potency in suppressing responses to painful stimuli. Isoflurane and sevoflurane are two commonly used volatile anesthetic agents in spine surgeries. Therefore, these agents' hypnotic and analgesic potencies should be distinguished and comprehended for the optimal administration of anesthesia. Consequently, we undertook this study to compare the analgesic and hypnotic potencies between these agents at equi-MAC concentrations, using the entropy monitor. Materials and Methods Forty patients undergoing lumbar spine surgery were randomly assigned to two groups receiving either isoflurane ( n = 20) or sevoflurane ( n = 20). After induction, maintenance of anesthesia was done with age-corrected 1.0 MAC of either isoflurane or sevoflurane. A standardized noxious stimulus was provided to all the patients after achieving a steady state of 1.0 MAC. The state entropy (SE), response entropy (RE), and RE–SE were recorded at baseline, prestimulus, and poststimulus time points in both groups. Statistical Analyses Data are presented as frequency and percentages for categorical variables and mean ± standard deviation for continuous variables. The comparison of categorical variables between the two groups was made using the Fisher's exact test, and the Student's t -test was used for continuous variables. A p -value of < 0.05 was considered to be statistically significant. Results At age-corrected 1.0 MAC, there was no significant difference in the SE, RE, and RE–SE in both the groups at any time point. Conclusion Our study shows that during a steady state of age-corrected 1.0 MAC single-agent anesthesia, sevoflurane and isoflurane have comparable analgesic and hypnotic potencies as measured by entropy indices when a standardized nociceptive stimulus is provided.

Signatures of Thalamocortical Alpha Oscillations and Synchronization With Increased Anesthetic Depths Under Isoflurane.

Background: Electroencephalography (EEG) recordings under propofol exhibit an increase in slow and alpha oscillation power and dose-dependent phase–amplitude coupling (PAC), which underlie GABAA potentiation and the central role of thalamocortical entrainment. However, the exact EEG signatures elicited by volatile anesthetics and the possible neurophysiological mechanisms remain unclear. Methods: Cortical EEG signals and thalamic local field potential (LFP) were recorded in a mouse model to detect EEG signatures induced by 0.9%, 1.5%, and 2.0% isoflurane. Then, the power of the EEG spectrum, thalamocortical coherence, and slow–alpha phase–amplitude coupling were analyzed. A computational model based on the thalamic network was used to determine the primary neurophysiological mechanisms of alpha spiking of thalamocortical neurons under isoflurane anesthesia. Results: Isoflurane at 0.9% (light anesthesia) increased the power of slow and delta oscillations both in cortical EEG and in thalamic LFP. Isoflurane at 1.5% (surgery anesthesia) increased the power of alpha oscillations both in cortical EEG and in thalamic LFP. Isoflurane at 2% (deep anesthesia) further increased the power of cortical alpha oscillations, while thalamic alpha oscillations were unchanged. Thalamocortical coherence of alpha oscillation only exhibited a significant increase under 1.5% isoflurane. Isoflurane-induced PAC modulation remained unchanged throughout under various concentrations of isoflurane. By adjusting the parameters in the computational model, isoflurane-induced alpha spiking in thalamocortical neurons was simulated, which revealed the potential molecular targets and the thalamic network involved in isoflurane-induced alpha spiking in thalamocortical neurons. Conclusion: The EEG changes in the cortical alpha oscillation, thalamocortical coherence, and slow–alpha PAC may provide neurophysiological signatures for monitoring isoflurane anesthesia at various depths.

Intraoperative administration of isoflurane improves survival in rats exposed to caecal ligation and puncture.

Emerging data suggest that volatile anaesthetic agents may be protective during critical illness. Three-month-old Sprague Dawley rats were randomly allocated to one of four groups: isoflurane during surgery followed by 3 days of isoflurane 0.8% (and intralipid i.v.), propofol during surgery and 314 μg kg-1 h-1 propofol for 3 days, isoflurane during surgery and intralipid for 3 days, and propofol during surgery and intralipid for 3 days. After induction with propofol or isoflurane, rats breathed oxygen 100% spontaneously via a nose cone. Propofol or intralipid was administered through a 22-gauge jugular vein i.v. catheter. Caecal ligation and puncture was performed through a paramedian incision. The surgical concentration of isoflurane was kept at 2%, and propofol was maintained at 800 μg kg-1 h-1. After recovery and 3 days of exposure to intralipid or anaesthetic agents, the rats were allowed to roam free in an adequately vented, temperature- and humidity-controlled cage with food and water ad libitum. Rats that received isoflurane for 3 days survived longer than the postoperative propofol group (P=0.0002, log-rank test). Among rats receiving no postoperative anaesthetic, those receiving isoflurane during surgery survived longer than those that received propofol during surgery group (P=0.0081). Exposure to isoflurane, as opposed to propofol, may improve survival in rats exposed to caecal ligation and puncture.

Erratum to: In horses undergoing volatile anaesthesia, does intraoperative alpha-2-agonist infusion improve recovery?

The original version of the article has been corrected, please see the full text for details of the correction.

The outcome of intravenous and inhalation anesthesia after pancreatic cancer resection: a retrospective study

BackgroundDifferent types of anesthesia may affect cancer patient’s outcomes, we compared the overall survival (OS) and disease-free survival (DFS) of patients with pancreatic cancer under total intravenous and inhalation anesthesia.MethodsThe authors collected the electronic medical records of patients who had accepted at a pancreatectomy from January 1, 2010 to December 31, 2016. Patients respectively received total intravenous anesthesia (TIVA) or inhalational anesthesia (INHA). Stabilized inverse probability of treatment weighting (SIPTW)was used to minimize differences. Kaplan–Meier survival was established to analyze the influence of sort of anesthesia on disease-free and overall survival. We compare the effects of each sort of anesthesia on cancer recurrence or metastasis and all-cause mortality.ResultsA total of 463 patients who had undergone pancreatic cancer resection were collected in this study, of which 421 patients were available (TIVA group, n = 114 INHA group, n = 307). After SIPTW there were no significant differences between the two groups in disease-free survival (hazard ratio, 1.01, 95%CI, 0.78 to 1.29, P = 0.959) or overall survival (hazard ratio, 1.11, 95%CI, 0.87 to 1.42, P = 0.405).ConclusionsIn conclusion, the present study showed no significant difference in overall survival and disease-free survival between total intravenous anesthesia and volatile anesthesia.