The Mechanisms of Sevoflurane-Induced Neuroinflammation

Sevoflurane is one of the most commonly used inhaled anesthetics due to its low blood gas coefficient, fast onset, low airway irritation, and aromatic smell. However, recent studies have reported that sevoflurane exposure may have deleterious effects on cognitive function. Although neuroinflammation was most widely mentioned among the established mechanisms of sevoflurane-induced cognitive dysfunction, its upstream mechanisms have yet to be illustrated. Thus, we reviewed the relevant literature and discussed the most mentioned mechanisms, including the modulation of the microglial function, blood–brain barrier (BBB) breakdown, changes in gut microbiota, and ease of cholinergic neurotransmission to help us understand the properties of sevoflurane, providing us new perspectives for the prevention of sevoflurane-induced cognitive impairment.

Inhaled Anesthetics: Environmental Role, Occupational Risk, and Clinical Use

Inhaled anesthetics have been in clinical use for over 150 years and are still commonly used in daily practice. The initial view of inhaled anesthetics as indispensable for general anesthesia has evolved during the years and, currently, its general use has even been questioned. Beyond the traditional risks inherent to any drug in use, inhaled anesthetics are exceptionally strong greenhouse gases (GHG) and may pose considerable occupational risks. This emphasizes the importance of evaluating and considering its use in clinical practices. Despite the overwhelming scientific evidence of worsening climate changes, control measures are very slowly implemented. Therefore, it is the responsibility of all society sectors, including the health sector to maximally decrease GHG emissions where possible. Within the field of anesthesia, the potential to reduce GHG emissions can be briefly summarized as follows: Stop or avoid the use of nitrous oxide (N2O) and desflurane, consider the use of total intravenous or local-regional anesthesia, invest in the development of new technologies to minimize volatile anesthetics consumption, scavenging systems, and destruction of waste gas. The improved and sustained awareness of the medical community regarding the climate impact of inhaled anesthetics is mandatory to bring change in the current practice.

Hydroxide ions amplified by water entanglement underly the mechanism of general anesthesia

It is believed that inhaled anesthetics occupy hydrophobic pockets within target proteins, but how inhaled anesthetics with diverse shapes and sizes fit into highly structurally selective pockets is unknown. For hydroxide ions are hydrophobic, we determined whether hydroxide ions could bridge inhaled anesthetics and protein pockets. We found that small additional load of cerebral hydroxide ions decreases anesthetic potency. Multiple-water entanglement network, derived from Ising model, has a great ability to amplify ultralow changes in the cerebral hydroxide ion concentration, and consequently, amplified hydroxide ions account for neural excitability. Molecular dynamics simulations showed that inhaled anesthetics produce anesthesia by attenuating the formation of multiple-water entanglement network. This work suggests amplified hydroxide ions underlying a unified mechanism for the anesthetic action of inhaled anesthetics.

Comparative study of Intraoperative Haemodynamics and recovery characteristics of desflurane and sevoflurane in patients receiving General Anaesthesia

Background: Inhaled anesthetics used for general anaesthesia have a rapid onset and offset of action. The Induction and recovery depends on anaesthetic drug solubility, cardiac output and minute ventilation. Sevoflurane and desflurane have low blood gas partition coefficients, and therefore share the advantage of faster onset and recovery from anaesthesia when compared to other inhaled anesthetics. Hence, we designed this prospective randomized study to compare the intraoperative haemodynamic parameters and recovery characteristics of desflurane and sevoflurane. Methods: Sixty patients aged between 18-50 years belonging to ASA I and II scheduled for elective general anaesthesia were enrolled in the study and randomly divided into two groups to receive desflurane(group D) and sevoflurane(group S) for the maintenance of anaesthesia. Both groups were premedicated, pre oxygenated and induced with propofol. Muscle relaxation maintained with vecuronium. Desflurane and sevoflurane concentrations were adjusted according to entropy parameters and clinical variables like HR, NIBP, MAP and SPO2. Neuromuscular blockade reversed with neostigmine and glycopyrrolate. Recovery characteristics assessed using modified Aldrete scoring. Results: The intraoperative haemodynamics was similar with both desflurane and sevoflurane, and was maintained within 20% of baseline values. However, early recovery characteristics were significantly better in group D. Time to eye opening was 6.63 + 2.17 min in group S versus 4.77 + 1.41 min in group D (P< 0.001). Time to Extubation was 8.03 + 2.54 min in group S and 5.93 + 1.44 min in group D (P < 0.001). Response to verbal commands was 8.77 + 3.01 min in group S and 6.97 + 1.67 min in group D (P < 0.001). Modified Aldrete score were significantly better in group D than group S at 1st min, 2nd min and 3rd min. Thereafter, modified Aldrete score assessed at 5, 10, 15, 30 and 60 min were similar in both groups. Conclusion: Both desflurane and sevoflurane produce similar stable haemodynamic profile. Despite the faster early recovery with desflurane, no significant differences were found between the two volatile anaesthetics after 5 minutes during intermediate recovery period.

Association between intraoperative administration of dexamethasone and survival after curative resection for non-small cell lung cancer (NSCLC): A propensity score matching analysis

Background: Few studies have suggested the correlation between intraoperative dexamethasone and oncological outcomes in non-small cell lung cancer (NSCLC) patients with radical resection. The existing data are inconsistent and inadequate, and more evidence is needed. We therefore undertook a propensity-matched cohort study to investigate the correlation.Methods: 832 patients with stage I to IIIa NSCLC who went through lung tumor resection between January 2008 and December 2013 were enrolled in our study. Propensity-score matching analysis created a population of 260 patients in the non-DEX group and 130 patients in the DEX group. Cox regression analyses were applied to compare the disease-free survival (DFS) and overall survival (OS) between patients who did not and did receive dexamethasone in the propensity score-matched cohort, as well as in the certain patients with high-risk factors of postoperative nausea and vomiting (PONV).Results: After propensity score matching, intraoperative dexamethasone was not significantly associated with DFS (HR: 0.944, 95%CI: 0.720-1.237, P = 0.655) and OS (HR: 1.210, 95%CI: 0.927-1.581, P = 0.486). Multivariable cox regression analysis revealed that intraoperative dexamethasone was not independent prognostic factor for DFS and OS in NSCLC patients undergoing surgical resection. In the subgroup analysis, including female subgroup, nonsmoking subgroup, long anesthetic time subgroup, VATS subgroup and inhaled anesthetics subgroup, intraoperative dexamethasone was not significantly associated with DFS and OS.Conclusion: There was no correlation between intraoperative administration of dexamethasone and survival in NSCLC patients after curative surgery. In the high-risk subgroups of PONV, that is, female, nonsmoking, long anesthetic time, VATS and inhaled anesthetics, patients given intraoperative dexamethasone had no better or poorer prognosis compared with patients not given intraoperative dexamethasone.