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 correlation between different operation timing of thoraco-scopic partial pneumonectomy and intraoperative intrapulmonary shunt rate in patients with novel coronavirus(SARS-CoV-2)infection.Methods A total of 120 patients,65 males and 55 females,aged 30-75 years,BMI 18.5-25.0 kg/m2,ASA physical status Ⅰ or Ⅱ,scheduled for elective thoracoscopic partial pneumo-nectomy from December 2022 to May 2023 were selected.The patients with SARS-CoV-2 infection were di-vided into three groups according to different operation timing after infection:5-8 weeks after infection(group B),9-12 weeks after infection(group C),and 13-16 weeks after infection(group D),30 pa-tients in each group.In addition,30 non-infected patients were selected as the control group(group A).Blood gas analysis was performed at 10 minutes of two-lung ventilation(TLV)and 15 and 30 minutes of one-lung ventilation(OLV)to measure radial artery and mixed venous blood gases.Intrapulmonary shunt rate(Qs/Qt)was calculated accordingly.Multiple linear regression analysis was used to investigate the cor-relation between different operation timing and intrapulmonary shunt rate in patients with SARS-CoV-2 infec-tion.The occurrence of postoperative pulmonary complications(PPCs)within 7 days after surgery was re-corded.Results Compared with group A,groups B and C exhibited significant decreases in PaO2 levels and increases in Qs/Qt ratios at 10 minutes of TLV as well as at 15 and 30 minutes of OLV(P＜0.05),group D exhibited significant decreases in PaO2 levels and increases in Qs/Qt ratios at 15 and 30 minutes of OLV(P＜0.05),group B exhibited significant increases in postoperative pulmonary infection rates and the incidence of respiratory failure within 7 days after surgery(P＜0.05).Compared with group B,the inci-dence of pulmonary infection and respiratory failure within 7 days after surgery were significantly reduced in group D(P＜0.05).Multiple linear regression analysis revealed that shorter infection time(β=-0.478,95％CI-3.857 to-1.231,P＜0.001),worsening clinical types of infection(β=0.274,95％CI 0.368 to 3.453,P=0.016),and preoperative persistent symptoms(β=-0.240,95％CI-5.986 to-0.537,P=0.019)were associated with increased intrapulmonary shunt rate at 10 minutes of TLV.Shor-ter infection time(β=0.267,95％CI 0.130 to 3.018,P=0.033),worsening clinical types of infection(β=-0.391,95％CI-4.715 to-1.323,P=0.001),preoperative persistent symptoms(β=-0.497,95％CI-10.484 to-4.491,P＜0.001),and preoperative dyspnea(β=-0.246,95％CI-8.596 to-0.691,P=0.022)were associated with increased intrapulmonary shunt rate at 15 minutes of OLV.Conclusion SARS-CoV-2 infection increases intrapulmonary shunt rate 5-8 and 9-12 weeks after infection,but the intrapulmonary shunt rate gradually recovers at 10 minutes of TLV 13-16 weeks after in-fection,and patients who undergo surgery during this interval have a lower incidence of PPCs.The shorter infection time,the aggravation of clinical classification of infection,and the presence of persistent symptoms before surgery are associated with the increase of intrapulmonary shunt rate.

Objective To observe the effect of pressure-controlled ventilation volume-guaranteed(PCV-VG)mode on respiratory mechanics,lung injury markers and postoperative pulmonary complications(PPCs)in thoracoscopic patients.Methods Fifty-nine patients undergoing elective thoracoscopic lobecto-my,29 males and 30 females,aged 18-64 years,BMI 18.5-26.0 kg/m2,ASA physical status Ⅰ or Ⅱ,were divided into two groups using a random number table method:the PCV-VG mode group(group P,n=29)and the volume-controlled ventilation(VCV)mode group(group V,n=30).The PCV-VG mode was used for one-lung ventilation(OLV)in group P,and the VCV mode was used in group V.Anesthesia in-duction and maintenance medications were consistent in all patients.PaO2 was recorded before induction of anesthesia,5 minutes after intubation,15 minutes after OLV,30 minutes after OLV,and 3 days postopera-tively,and oxygenation index(OI)and intrapulmonary shunt rate(Qs/Qt)were calculated.Peak airway pressure(Ppeak),pulmonary dynamic compliance(Cdyn),and driving pressure(DP)were recorded 5 minutes after intubation,15 minutes after OLV,and 30 minutes after OLV.Clara cell secretory protein-16(CC-16)and interleukin-6(IL-6)concentration were measured before induction of anesthesia and after ex-tubation.Recording the occurrence of PPCs within 1 week after surgery.Results Compared with group V,Ppeak and DP were significantly reduced,Cdyn was increased significantly in group P 15 minutes and 30 minutes after OLV(P＜0.05),PaO2 and OI were significantly increased in group P 3 days postoperatively(P＜0.05),CC-16 and IL-6 concentrations were significantly reduced in group P after extubation(P＜0.05).Compared with group V,the incidence of PPCs was significantly reduced in group P(P＜0.05).Conclusion During one-lung ventilation for thoracoscopic surgery,the pressure-controlled ventilation vol-ume-guaranteed mode reduces peak airway pressure and driving pressure,improves pulmonary dynamic compliance and improves oxygenation,reduces the incidence of PPCs.

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.