No abstract

Post-operative cognitive dysfunction has been widely observed, especially in older patients. An association of post-operative cognitive dysfunction with the neurodegenerative diseases, such as Alzheimer's disease, has been suggested. Neuroinflammation contributes to Alzheimer pathology, through elevated pro-inflammatory cytokines and microglial activation in the CNS leading to neuronal damage, synaptic disruption and ultimately cognitive dysfunction. We compare the effects of three different, clinically-used, anesthetics on microglial activation with, and without, the prototypical inflammatory trigger, lipopolysaccharide (LPS). Microglial BV-2 cell cultures were first exposed to isoflurane, sevoflurane (each at 2 concentrations) or propofol for 6 h, and cytokine levels measured in lysates and media. The same experiments were repeated after 1 h LPS pre-treatment. We found; 1) anesthetics alone have either no or only a small effect on cytokine expression; 2) LPS provoked a large increase in microglia cytokine expression; 3) the inhaled anesthetics either had no effect on LPS-evoked responses or enhanced it; 4) propofol nearly eliminated the LPS pro-inflammatory cytokine response and improved cell survival as reflected by lactate dehydrogenase release. These data suggest that propofol may be a preferred anesthetic when it is desirable to minimize neuroinflammation.

BackgroundDexmedetomidine can facilitate a smooth extubation process and reduce the requirement of sevoflurane and emergence agitation when administrated perioperatively. We aimed to observe the extubation process and the recovery characteristics in pediatric patients undergoing tonsillectomy while anesthetized with either high-concentration sevoflurane alone or low-concentration sevoflurane combined with pre-medication of single dose of intravenous dexmedetomidine.MethodsSeventy-five patients (ASA I or II, aged 3–7 years) undergoing tonsillectomy were randomized into three equal groups: to receive intravenous saline (Group D0), dexmedetomidine 1 μg/kg (Group D1), or dexmedetomidine 2 μg/kg (Group D2) approximately 10 min before anesthesia. Before the end of surgery, sevoflurane were adjusted to 1.5 times, 1.0 time and 0.8 times the minimal effective concentration in groups D0, D1 and D2, respectively. The sevoflurane concentration for each group was maintained for at least 10 min before the tracheal deep-extubation was performed. The extubation event, recovery characteristics and post-op respiratory complications were recorded.ResultsAll tracheal tubes in three groups were removed successfully during deep anesthesia. Nine patients in Group D0, three patients in Group D1, and two patients in Group D2 required oral airway to maintain a patent airway after extubation. The frequency of oral airway usage in groups D1 and D2 were significantly lower than that in Group D0. The percentages of patients with ED and the requirements of fentanyl in groups D1 and D2 were also significantly lower than those in Group D0. The time from extubation to spontaneous eye opening in Group D2 was longer than that in groups D0 and D1. The times of post-anesthesia care unit discharge in groups D0 and D2 were longer than that in Group D1. No other respiratory complications and vomiting were observed.ConclusionA single dose of intravenous dexmedetomidine as pre-medication in combination with low-concentration sevoflurane at the end of surgery provided safe and smooth deep extubation condition and it also lowered the emergence agitation in sevoflurane-anaesthetized children undergoing tonsillectomy. Preoperative dexmedetomidine at 1 μg/kg did not prolong postoperative recovery time.Trial registrationChinese Clinical Trial Registry (ChiCTR): ChiCTR-IOR-16008423, date of registration: 06 may 2016.

BackgroundIt has been known that Dexmedetomidine pre-medication enhances the effects of volatile anesthetics, reduces the need of sevoflurane, and facilitates smooth extubation in anesthetized children. This present study was designed to determine the effects of different doses of intravenous dexmedetomidine pre-medication on minimum alveolar concentration of sevoflurane for smooth tracheal extubation (MACEX) in anesthetized children.MethodsA total of seventy-five pediatric patients, aged 3–7 years, ASA physical status I and II, and undergoing tonsillectomy were randomized to receive intravenous saline (Group D0), dexmedetomidine 1 μg∙kg−1 (Group D1), or dexmedetomidine 2 μg∙kg−1 (Group D2) approximately 10 min before anesthesia start. Sevoflurane was used for anesthesia induction and anesthesia maintenance. At the end of surgery, the initial concentration of sevoflurane for smooth tracheal extubation was determined according to the modified Dixon’s “up-and-down” method. The starting sevoflurane for the first patient was 1.5% in Group D0, 1.0% in Group D1, and 0.8% in Group D2, with subsequent 0.1% up or down in next patient based on whether smooth extubation had been achieved or not in current patient. The endotreacheal tube was removed after the predetermined concentration had been maintained constant for ten minutes. All responses (“smooth” or “not smooth”) to tracheal extubation and respiratory complications were assessed.ResultsMACEX values of sevoflurane in Group D2 (0.51 ± 0.13%) was significantly lower than in Group D1 (0.83 ± 0.10%; P < 0.001), the latter being significantly lower than in Group D0 (1.40 ± 0.12%; P < 0.001). EC95 values of sevoflurane were 0.83%, 1.07%, and 1.73% in Group D2, Group D1, and Group D0, respectively. No patient in the current study had laryngospasm.ConclusionDexmedetomidine decreased the required MACEX values of sevoflurane to achieve smooth extubation in a dose-dependent manner. Intravenous dexmedetomidine 1 μg∙kg−1 and 2 μg∙kg−1 pre-medication decreased MACEX by 41% and 64%, respectively.Trial registrationChinese Clinical Trial Registry (ChiCTR): ChiCTR-IOD-17011601, date of registration: 09 Jun 2017, retrospectively registered.