Lean Body Mass In The Clinical Observation Of Obese Patients In The Intravenous General Anesthesia Induction

Objective:By analyzing the circulation and NI variation in the induction of intravenous anesthesia that based on different dosing scalars (LBM、IBW、TBW), so as to find out a more scientific dosing scalar for obese patients, and make the clinical medication more accurate and safer.Methods:Adopt the method of prospective cohort study. Select of 120 patients that will accept general anesthesia surgery, including 60 cases of male,60 cases of female.ASA Ⅰ-Ⅱ, aging 20-60 years old, operating time unlimited.120 patients were divided into four groups according to BMI:group Ⅰ, normal weight (BMI 18.5 ～23.9); groupⅡ, overweight (BMI 24.0～26.9);group Ⅲ, obese (BMI 27.0～29.9); group IV, severely obese (BMI>30.0).Each group has 30 cases, group Ⅰ～Ⅳ were randomly divided into 3 groups:group A (dosing scalar by LBM);Group B (dosing scalar by IBW);group C (dosing scalar by TBW). Checked patients correctly and opened venous access,then gave Multiple electrolyte fluid (10～12 ml kg-1h-1), monitored by non-invasive blood pressure (BP), electrocardiogram (ECG), blood oxygen saturation (SPO2) routinely.At the same time,monitored Narcotrend index (NI) with the German MT Monitor Technick Narcotrend Compact. Induction of anesthesia:same person with same rate to give midazolam 0.04mg/kg, fentanyl 4ug/kg, propofol 2.5 mg/kg(medium/long chain), rocuronium lmg/kg. Pressurized oxygen via face mask for 5 minutes and then completed tracheal intubation by same person using UE visual laryngoscope, confirmed the position of the tracheal tube and connected anesthesia machine for mechanical ventilation. Recorded the heart rate,systolic blood pressure,diastolic blood pressure,mean blood pressure and narcotrend index respectively at the moment just before induction(T1),the moment before intubation(T2) and the moment after intubation(T3).The corresponding values of T1 were the average of three times of measurement. Datas are analyzed by SPSS 17.0 software packet, the form of measurement data to mean and standard deviation, and the measurement data in addition to the general situation of group which tested by One-Way ANOVA analysis all adopt t test, Count data by chi-square test, p< 0.05 that was statistically significant.Results:In group Ⅰ,there were no statistical significance between group A,group B and group C for changes of circulation and Narcotrend index after induction;in group Ⅱ,between group A and group C,changes of circulation and Narcotrend index had statistical significance after induction (p< 0.05), between group B and group C, changes of Narcotrend index were statistically significant (p< 0.05), and no statistical difference between group A and group B.In group Ⅲ, Ⅳ there were statistical difference for changes of circulation and Narcotrend index after induction to group A,group B and group C each other. The comparison of changing range of circulation and anesthetic depth was group C> group A> group B;Among them, the group Ⅲ (p<0.05);and the groupⅣ had a significantly statistical difference (p< 0.001).Conclusion:(1) For obese patients without basic diseases, LBM may be considered as a dosing scalar to calculate the inductive doses that in intravenous induction, little impact on circulation,and appropriate anesthesia depth after induction. (2) For obese patients without basic diseases, with the increase of BMI, the guiding significance of LBM also increased.