Objective To establish an external calibration method of atomic absorption spectrometry-graphite furnace for determination of heavy metals Pb,Cd,Sb in tetracaine hydrochloride injection.Methods Microwave digestion for the pretreatment method was used,three kinds of heavy metal elements were determined by graphite atomic absorption spectrometry-graphite furnace Results The linear ranges of Pb,Cd,Sb were 0-80.0 ng/mL,0-2.0 ng/mL,0-40.0 ng/mL,therecovies were 92.7%-105.7%,95.8%-103.4%,92.1%-103.5%,respetively.The relative standard deviationless than 6.0%(n=9).Conclusion The method is simple and accurate,which can be used for the control of Pb,Cd,Sb in tetracaine hydrochloride injection.

Objective:To investigate the relationship between the timing of pulmonary surgery and postoperative pulmonary complications (PPCs) after severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection.Methods:Sixty-eight American Society of Anesthesiologists Physical Status classification Ⅰor Ⅱ patients of either sex, with body mass index of 18-30 kg/m 2, who were first infected with SARS-CoV-2 after December 2022, undergoing elective thoracoscopic partial pneumonectomy from January to May 2023, were included in this prospective cohort study. The patients were divided into 2 groups ( n=34 each) according to the time between the date of surgery and SARS-CoV-2 infection: 5-10 weeks group and 11-16 weeks group. The preoperative persistent symptoms and dyspnea before operation were recorded. The serum concentrations of interleukin-6 and tumor necrosis factor-alpha were determined by enzyme-linked immunosorbent assay at 1 day before operation and 2 h and 1 and 2 days after operation. The white blood cell count and serum C-reactive protein concentration were measured at 1 day before operation and 1 and 2 days after operation. The occurrence of PPCs and length of postoperative hospital stay were recorded. Logistic regression was used to analyze the relationship between PPCs and timing of pulmonary surgery after SARS-CoV-2 infection. Results:Two patients in each group were excluded from the study because of conversion to thoracotomy. Thirty-two patients were finally included in each group. Compared with 5-10 weeks group, the ratio of preoperative persistent symptoms and dyspnea was significantly decreased, the serum concentrations of interleukin-6, tumor necrosis factor-alpha and C-reactive protein and white blood cell count were decreased at each time point after operation, the incidence of PPCs and postoperative pulmonary infection was decreased, and the length of postoperative hospital stay was shortened in 11-16 weeks group ( P<0.05). Multivariate logistic regression analysis showed that short time from the date of surgery to infection ( OR=1.754, 95% confidence interval[ CI] 1.509-2.038, P<0.001), preoperative persistent symptoms ( OR=2.523, 95% CI 2.047-3.110, P<0.001), preoperative dyspnea ( OR=1.875, 95% CI 1.406-2.500, P<0.001) and high white blood cell count at 1 day after surgery ( OR=0.676, 95% CI 0.651-0.701, P<0.001) were independent risk factors for PPCs. Conclusions:The risk of PPCs is lower in the patients undergoing pulmonary surgery at 11-16 weeks after SARS-CoV-2 infection than at 5-10 weeks after infection. Short time from the date of surgery to infection is an independent risk factor for PPCs.