The effects of barium chloride(BaCl2)on several items of the immune functions of mice were observed.After the mice had drunk water containing 10 mg/L and 100 mg/L of BaCl2 for one month,evident histological changes of their liver were observed but no remarkable changes were found in the spleen,the lymph nodes,the thymus,the bone marrow and the peripheral leucocytes.In the 100 mg/L group,the transformation rate of the ConA-stimulated lymphocytes of the spleen was significantly lower than that of the control(P

Objective:To evaluate the dose-effect relationship of compound lidocaine hydrochloride for transverse abdominal plane-rectus abdominis sheath block (TAP-RSB) for postoperative analgesia in elderly patients undergoing laparoscopic radical colon cancer surgery with general anesthesia.Methods:Elderly patients of either sex, aged≥65 yr, with body mass index <30 kg/m 2, of American Society Anesthesiologists physical status Ⅰ-Ⅲ, undergoing elective laparoscopic radical colon cancer surgery with general anesthesia, were selected.After induction of general anesthesia, compound lidocaine hydrochloride was given under ultrasound guidance for bilateral TAP block (20 ml on each side) and for bilateral RSB (10 ml on each side), with the initial concentration of 0.4%.Each time the concentration increased/decreased in the next patient depending on whether or not the analgesia was effective.The ratio between the two successive concentrations was 1.00∶1.15.The analgesic effects were evaluated by the Numerical Rating Scale at 1 h intervals from the time of postoperative admission to the post-anesthesia care unit until 8 h after TAP-RSB (Numerical Rating Scale ≤ 3 was considered as effective analgesia). The probit method was used to calculate the half effective concentration (EC 50) and 95% effective concentration (EC 95) and 95% confidence interval of compound lidocaine hydrochloride. Results:The EC 50 and EC 95(95% confidence interval)of compound lidocaine hydrochloride for TAP-RSB were 0.289% (0.232%-0.352%) and 0.404% (0.345%-0.970%), respectively, when used for postoperative analgesia in elderly patients undergoing laparoscopic radical colon cancer surgery with general anesthesia. Conclusions:The EC 50 and EC 95 of compound lidocaine hydrochloride for TAP-RSB are 0.289% and 0.404%, respectively, when used for postoperative analgesia in elderly patients undergoing laparoscopic radical colon cancer surgery with general anesthesia.