Several Joint Inhalation Anesthesia Clinical Comparison

Background and objectives Endotracheal intubation is essential tosecure the airway and to provide oxygenation for general anesthesia. However, endotracheal intubation is also a powerful noxious stimulus and the response may have deleterious effects on the respiratory, neurological, or cardiovascular system. It was evident that deeper levels of anesthesia are required to blunt the response to the stimulation of endotracheal tube (ETT) intubation than to suppress the pain from surgical incision. To anesthetize the trachea membrane with local anesthetics may make the deep anesthesia unnecessary and therefore reduce the general anesthetics requirement. The traditional methods of anesthetizing trachea membrane are either last too short time or have potential danger of local anesthetic toxication. This study used EMLA cream pre-coating ETT tube, a safe, effective long lastingmethod, to provide trachea membrane topical anesthesia and investigated whether the requirement of inhalational general anesthetics for general anesthesia or the combination of general and epidural anesthesia is reduced.Methods Sixty ASA I-II patients undergoing upper abdominal surgerieswere randomly assigned to 4 groups. Patients in group GA accepted general anesthesia without ETT pre-coated with EMLA cream. Patients in group GA+EMA also had general anesthesia but with ETT pre-coated with EMLA. Patients in group GA+EA accepted the combination of general and epidural anesthesia without ETT pre-coated with EMLA. Patients in group GA+EMA+EA had the combination of general and epidural anesthesia with ETT pre-coated with EMLA. All the patients in various groups were premedicated with sodium luminal and atropine. In group GA+EA and group GA+EMA+EA, epidural anesthesia were performed before the induction of general anesthesia. For the induction of anesthesia, midazolam 0.1 mg ■ kg"1, Fentanyl 4 p,g ■ kg"1, Propofol 1 mg ? kg"1 and vencuronium 0.1 mg ? kg"1 were administered. General anesthesia was maintained with inhale isoflurane and intravenous vecuronium. The inhalational concentration of isoflurance was adjusted according to the depth of anesthesia which was estimated by cardiovascular responses and the other signs. The end-tidal isoflurane concentrations were continuously recorded and the consumption of isoflurane were calculated by Equation: The consumption of isoflurane (ml)=fresh oxgen flow(l/min) X lOOOxthe isoflurane concentrations of vaporize X time(min)/196.Results To maintain a satisfactory anesthesia, the requirements ofisoflurance (expressed as MAC) were significantly different in each group (P=0.000). Group GA needed the highest isoflurane inhaled concentration (1.01+0.11MAC). Pre-coating ETT with EMLA decreased isoflurance inhaled concentration by 12% in general anaesthesia ( P=0.000 compared to general anesthesia alone). Epidural anesthesia reduced isoflurance requirement dramatically when it was combined with general anesthesia ( concentration dropped 38%, P=0.000). However, pre-coating ETT wih EMLA cream further decreased the need of isoflurane by 50% in epidural and general combined anesthesia (P=0.000 compared to general anesthesia alone). Group GA needed the largest volume of isoflurane consumed (12.9±1.8ml). Pre-coating ETT with EMLA decreased consumption of isoflurance by 13% in general anaesthesia ( P=0.002 compared to general anesthesia alone). Epidural anesthesia reduced consumption of isoflurance dramatically when it was combined with general anesthesia (dropped 48%, P=0.000). However, pre-coating ETT wih EMLA cream further decreased the consumption of isoflurane by 59% in epidural and general combined anesthesia (P= 0.000 compared to general anesthesia alone). There are the least incidence of side effects in GA+EMA+EA group (P=0.000) . There are not intraoperative awareness in all patients.Conclusion Pre-coating endotracheal tubes can successfully reduce theinhalational anesthetics need either in general anesthesia or the combination of general anesthesia and epidural anesthesia, and least incidence of sideeffects in postoperation . This simple technique is excellent to avoid unnecessary deep anesthesia and to save expensive general anesthetics.