In vivo field recordings effectively monitor the mouse cortex and hippocampus under isoflurane anesthesia

Isoflurane is a widely used inhaled anesthetic in the clinical setting. However, the mechanism underlying its effect on consciousness is under discussion. Therefore, we investigated the effect of isoflurane on the hippocampus and cortex using an in vivo field recording approach. Our results showed that 1.3%, 0.8%, and 0.4% isoflurane exerted an inhibitory influence on the mouse hippocampus and cortex. Further, high frequency bands in the cortex and hippocampus showed greater suppression with increasing isoflurane concentration. Our findings suggest that in vivo field recordings can monitor the effect of isoflurane anesthesia on the mouse cortex and hippocampus.

CLINICAL SUMMARY ON ACUPUNCTURE COMBINED WITH ENFLURANE-INHALATION ANESTHESIA FOR RESECTION OF ESOPHAGEAL CARCINOMA

Objective: To observe the clinical effect of acupuncture combined with general anesthesia by inhaling enflurane for esophageal carcinoma resection. Methods: 120 cases of esophageal carcinoma patients were randomly divided into acupuncture+inhalation of enflurane (A+IE, n=40), electrical stimulation (ES)+IE (n=41) and IE (control, n=39) groups. In all the 3 groups, vecuronium, fentanyl, propofol (same dose) were given intravenously to induce anesthesia before operation, and during operation, fentanyl (2 ug/kg/hr) and vecuronium (0.03 mg/kg/0.5hr) and appropriate concentration of enflurane were given to the patients for maintaining anesthesia and muscular relaxation. In group A, Xiayifeng (below TE 17), Sanyangluo (TE 8) to Ximen (PC 4) were punctured and stimulated electrically, and in group B, these acupoints were stimulated electrically via cutaneous plate electrodes. Results: The anesthetic effect grade I rates of A+IE, ES+IE and IE groups were 67.50%, 68.29% and 28.21% respectively. There was a significant difference between A+IE or ES+IE and IE groups (P<0.001). In the process of anesthesia, the mean concentrations of the inhaled enflurane in A +IE, ES+IE and IE groups were 0.55% and 0.50% and 0.83% separately. The average concentrations of A+IE and ES+IE groups were lower 33.73% and 39.76% than that of group IE (P<0.005). Conclusion: Acupuncture combined with enflurane inhalation can enhance anesthetic effect, reduce the dose of the inhaled enflurane.

A comparison between vital capacity induction and tidal breathing induction techniques for the induction of anesthesia and compound A production

Background Vital capacity induction and tidal breathing induction are currently administered for inhalation induction of anesthesia with sevoflurane. The aim of this study was to compare them using sevoflurane with respect to induction time,complications of inhalation induction, and compound A production in adult patients.Methods Fifty-one women with American Society of Anesthesiologists physical status Ⅰ-Ⅱ undergoing mammary gland tumorectomy were randomly assigned to receive either vital capacity induction or tidal breathing induction with 8% sevoflurane at 6 L/min followed by laryngeal mask airway insertion. Induction times, complications of inhalation induction,and vital signs were recorded. Inspired concentrations of compound A were assayed and sofnolime temperatures were monitored at one-minute intervals after sevoflurane administration.Results The time to loss of eyelash reflex was significantly shorter with the vital capacity induction technique than with the tidal breathing induction technique （（43.8±13.4） seconds vs. （70.8±16.4） seconds, respectively; P 〈0.01）.Cardiovascular stability was similar in both groups. The incidence of complications was significantly less with the vital capacity induction technique than with the tidal breathing induction technique （7.7% vs. 32%, respectively; P 〈0.01）.However, the mean and maximum concentrations of compound A during induction were significantly higher in the vital capacity group than those in the tidal breathing group （P 〈0.05）; compound A concentration at the beginning of anesthesia maintenance was （40.73±10.83） ppm in the vital capacity group and （29.45±7.51） ppm in tidal breathing group （P=0.019）.Conclusion For inhalation induction of anesthesia, the vital capacity induction was faster and produced fewer complications than that for tidal breathing induction, but increased compound A production in the circuit system.