The Effects Of Postural Factor On The Entropy Index And The Bispectral Index Of Patients With General Anesthesia

ObjectiveTo discuss the effects of postural factor on the Entropy index and the Bispectral index of patients with.general anesthesia by observing the change of two indexes of patients who had transformed different positions in the same depth of anesthesia. And to evaluate the accuracy of Entropy index when it was used for monitoring the depth of anesthesia of patients with different positions.Methods120 ASA Ⅰ-Ⅱ patients,25～55yr, BMI18-24kg/m2, were enrolled in this study. MAP, HR, SpO2, EtCO2, RE, SE and BIS were monitored. The trachea topical anesthesia with 2% lidocaine was inhaled. Anesthsia was induced with propofol-remifentanil given by target controlled infusion(TCI).The target effect site concentration of propofol was 3 ug/ml and that of remifentanil was 4 ng/ml.Patients were intubated after loss of consciousness. Stop using remifentanil, the target effect site concentration was 4 ug/ml.After maintaining steady state target controlled concentration for 10 minutes, BIS, SE, RE values were recored at 5 min intervals for 3 readings. The patient position was then resetted to head-down position, horizontal position, and head-up position. Each kind of positon was kept 15 min, the datas were recorded at 5 min interals for 3 readings. Take the average value of three times datas. Patients were interviewed for any recall or awareness events at the second and the seventh day after the operation.Results(1)No patients showed intraoperative awareness. No patients has drug allergy reaction or serious complications.(2)After maintaining steady effect-site concentration, then change the patients position. HR, MAP, SpO2, EtC02 in different time do not have significant change (P>0.05).(3)The values of BIS, SE, RE of horizontal position were 46.4±3.9.47.8 ±4.3.49.8±2.5, and when shift to head-down position, the value was 48.4± 4.5 、49.2±3.8.50.0±3.7. After resetting the horizontal position, the BIS, SE, RE values were 46.4±5.0.47.8±3.8.49.8±2.1. And when shift to head-up position, the values were 45.5±4.5.47.0±2.6.49.8±3.2.The values of BIS, SE, RE were found to be unsignificant between two times horizontal position (P>0.05). The values of BIS and SE of head-down position were much higher than the horizontal position (P<0.05), these stepwise difference in RE values were unsignif icant. The values of BIS and SE of head-up position were much lower than the horizontal position (P<0.05), these stepwise difference in RE values were unsignificant. Compared with the head-down position, the values of BIS and SE of head-up position were much lower (P<0.05), these stepwise differences in RE values were unsignificant.ConclusionThe influence of postural factor on the Entropy index was less than on the Bispectral index. Compared with BIS, entropy was more accurate for the inperprtation of the patient who needs to change the position.