Objective:To observe the influence of methylprednisolone in the respiratory mechanical parameters in the elderly patients undergoing major surgeries with general anesthesia intubation after mechanical ventilation,and to investigate whether methylprednisolone can improve the respiratory system degenerative diseases and benefit the mechanical ventilation. Methods:Sixty patients undergoing elective line laparotomy were divided into experimental group and conrol group (n=30) according to their wishes.The patients in experimental group receieved intravenous injection of methylprednisolone 1 mL (40 mg) after endotracheal intubation,and the patients in control group receieved 1 mL intravenous saline water injection.The airway peak pressure (Ppeak), airway platform (Pplat), lung compliance (Compl), and airway resistance (Raw) of the patients in two groups were recorded at the time of immediately before administration and 10,20,30,40 min after administration.The arterial blood oxygen partial pressure(PaO2),arterial blood CO2 partial pressure(PaCO2),CO2 partial pressure at the end of breathe out(PetCO2) of the patients were detected at the time of immediately before administration and 20 min after administration.Results:Compared with before administration, the respiratory mechanics parameters of the patients in control group 10,20,30,40 min after administration had no statistically significant differences (P>0.05);the Comple of the patients in experimental group was singnificantly increased (P<0.05), and the Ppeak, Pplat,and Raw were significantly decreased (P<0.05).Compared with control group, the Compl of the patients in experiment group 10,20,30,and 40 min after administration were significantly increased (P<0.05),and the Ppeak, Pplat, and Raw were decreased (P<0.05).Compared with before administration,the PaO2,PaCO2,and PetCO2 of the patients in control group 20 min after administration had no significant differences(P>0.05);the PaCO2 and PetCO2 of the patients in experimental group 20 min after administration were decreased(P<0.05),and the PaO2 was increased(P<0.05).Compared with control group,the PaCO2 and PetCO2 of the patients in experimental group 20 min after administration were decreased(P<0.05),and the PaO2 was increased(P<0.05).Conclusion:Methylprednisolone can obviously reduce PaCO2,Peak, and Pplat and increase PaO2 and Compl;methylprednisolone has possibility in improving the adverse effects of degenerative disease of respiratory system on general anesthesia in the elderly patients.

Objective To study the plasma TNF-α and endothelin (ET) levels in patient with subarach-noid hemorrhage(SAH). Methods The plasma TNF-α and ET levels were measured by ELISA and radioimmunity at 1,3,7,14 and 21 d after onset of SAH in 45 patients. Results The plasma TNF-α and ET levels in patients with SAH were higher than the normal controls(P<0.01),among which the highest levels appeared at 3 d and 7 d,and the levels of plasma TNF-α and ET in patients with SAH were decreased at 14 d. Those of high Hunt-Hess grade～groups was higher than those of lower grade～groups(P<0.01). Conclusion The plasma TNF-α and ET levels are significantly elevated in the patients with SAH,which suggests that TNF-α and ET may play an important role in the pathogenesis of SAH,and which suggests that is one of the possible ways to prevent and treat cardiovascular spasm (CVS) after SAH by inhibiting TNF-α and ET.

Objective To evaluate the measurement uncertainty of the detecting procedure of amino acids and carnitines by the Waters ACQUITY TQD tandem mass spectrometer and PerkinElmer NeoBaseTM non‐derivatized MSMS kit ,and to discuss the meaning of evaluation .Methods According to the method provided by the Medical Laboratories‐Evaluation and Expression of Measurement Uncertainty ,the internal quality control was detected by using two different batch codes of kit for 20 d ,once before and after the routine sample detection on each working day ,the detector were randomly changed ,and then the measurement uncer‐tainty introduced by measurement reproducibility was calculated;the amino acid external assessment quality control data in 20 times of neonatal hereditary metabolic disease tandem mass spectrometry screening provided by the National Center for Clinical Laborato‐ry in 2014 and 2015 ,and the same and 16 times of carnitines external assessment quality control data were performed the statistics , and then the measurement uncertainty introduced by bias was calculated .Next the relative standard uncertainty and the relative ex‐panded uncertainty according to the measurement uncertainty introduced by bias and measurement reproducibility were calculated . The allowed total error indicators of amino acid and carnitines external quality assessment in the neonatal hereditary metabolic dis‐ease tandem mass spectrometry screening by the National Center for Clinical Laboratory were used as the target expanded uncer‐tainty .Results The relative expanded uncertainties of citrulline ,methionine ,phenylalanine ,propionyl carnitine ,octanoyl carnitine , dodecanoyl carnitine ,palmitoyl carnitine and octadecanoyl carnitine were 19 .1% -26 .1% (k=2) ,which were smaller than the tar‐get uncertainty .The relative expanded uncertainties of leucine ,tyrosine ,valine ,free carnitine were 31 .0% -43 .3% (k=2) ,which were greater than the target uncertainty .The uncertainty of isovaleryl carnitine needed to be estimated separately .Conclusion As‐sessing the measurement uncertainty of the detecting procedure of amino acids and carnitines by the non‐derivatized tandem mass spectrometer method can not only provide an opportunity for continuously improving the detection quality ,but also can help the ex‐perimental technique staffs to interpret the test data correctly and the clinician to use the detection reports correctly .

Objective:To explore the efficacy and safety of treating advanced esophageal cancer by implanting the common stent and the radioactive 125I particle stent with endoscope. Methods:The clinical data of patients with advanced esophageal cancer admitted to Jingbian County People's Hospital of Shaanxi Province, the First Affiliated Hospital of Xi'an Medical University, Xijing Hospital of Digestive Diseases of Air Force Medical University and the First Hospital of Yulin of Shaanxi Province from December 2014 to December 2020 were retrospectively analyzed. Patients were divided into common stent group ( n=66) and radioactive particle stent group ( n=34) according to different stent types. The postoperative complications, Karnofsky performance status (KPS) score, dysphagia score, restenosis rate and quality of life were compared between the two groups. Results:The incidences of postoperative retrosternal pain in the common stent group and the radioactive particle stent group were 65.2% (43/66) and 47.1% (16/34) respectively. The incidences of pharyngeal pain and hoarseness were 12.1% (8/66) and 5.9% (2/34) . The incidences of abdominal pain were 9.1% (6/66) and 2.9% (1/34) . The incidences of errhysis were 3.0% (2/66) and 2.9% (1/34) . The incidences of vomiting and nausea were 7.6% (5/66) and 5.9% (2/34) respectively. There were no statistically significant differences between the two groups ( χ2=3.04, P=0.081; χ2=0.40, P=0.527; χ2=0.53, P=0.467; χ2<0.01, P>0.999; χ2<0.01, P>0.999) . In the two groups, KPS scores in the first, second, third and sixth month after operation were higher than those before operation (all P<0.05) . KPS scores of the radioactive particle stent group in the second, third and sixth month were significantly higher than those of the common stent group [ (89.73±7.84) points vs. (82.37±7.42) points, t=4.62, P<0.001; (93.63±8.13) points vs. (88.33±7.28) points, t=3.74, P<0.001; (92.78±6.26) points vs. (87.28±8.73) points, t=3.77, P<0.001]. The dysphagia scores of patients in the two groups in the first, second, third and sixth month were lower than those before operation (all P<0.05) . The dysphagia scores of the radioactive particle stent group in the third and sixth month after operation were significantly lower than those of the common stent group [ (0.68±0.12) points vs. (2.33±0.32) points, t=26.20, P<0.001; (0.82±0.22) points vs. (2.67±0.24) points, t=36.92, P<0.001]. In the third month after operation, the restenosis rate of the radioactive particle stent group was significantly lower than that of the common stent group [5.88% (2/34) vs. 42.4% (28/66) , χ2 =14.27, P<0.001]. The scores of QLQ-C30 and OES-18 scales in the first, second, third and sixth month after operation were lower than those before operation (all P<0.05) . The scores of QLQ-30 scale in the radioactive particle stent group in the second, third and sixth month were significantly lower than those in the common stent group [ (19.12±3.02) points vs. (21.22±2.87) points, t=3.39, P=0.001; (15.04±1.68) points vs. (20.43±2.23) points, t=12.39, P<0.001; (14.38±2.18) points vs. (19.77±3.67) points, t=9.20, P<0.001]. The scores of OES-18 scale in the radioactive particle stent group were also significantly lower than those in the common stent group [ (17.13±2.07) points vs. (20.64±2.11) points, t=7.95, P<0.001; (15.22±1.88) points vs. (19.24±1.76) points, t=10.62, P<0.001; (14.74±2.36) points vs. (18.53±3.27) points, t=6.01, P<0.001]. Conclusion:The radioactive particle stent can improve the quality of life of patients with advanced esophageal cancer with esophageal stenosis, so as to improve dysphagia and reduce the restenosis rate after operation. However, whether it is obviously superior to common stent in prolonging survival time and reducing complications needs to be further confirmed by a multicenter, prospective, large-sample randomized controlled study.

BACKGROUND:Unicompartmental knee arthroplasty can effectively treat severe unilateral knee osteoarthritis.It has been found that posterior tibial cortical fracture is prone to occur after unicompartmental knee arthroplasty.The fracture begins at the keel groove of tibial osteotomy.The tibial prosthesis riser length affects the biomechanical results of the knee joint after unicompartmental knee arthroplasty. OBJECTIVE:To investigate the effect of tibial prosthesis riser length on knee biomechanics in unicompartmental knee arthroplasty,and to find out the relationship between prosthesis riser length and anterior and posterior tibial diameters of patients. METHODS:Computed tomography image data and commonly used unicompartmental prostheses were selected from a 37-year-old healthy female with no history of knee disease.A natural knee joint model was established and a unicompartmental prosthesis model was built.Eight different lengths of tibial prosthesis risers were established,with a minimum length of 31 mm and a maximum length of 34.5 mm in 0.5 mm increments,for comparison with the commonly used hospital prosthesis riser length of 33.2 mm.The material of the femoral component and tibial disc was cobalt-chromium-molybdenum alloy,and the tibial spacer was ultra-high molecular weight polyethylene.The biomechanical changes of the knee joint were observed using finite element analysis software loaded with 1000 N over the femur. RESULTS AND CONCLUSION:(1)The tibial stress was minimal at a tibial prosthesis riser length of 33 mm;the anterior cruciate ligament stress was minimal;the lateral meniscus stress was minimal,and the femoral prosthesis stress was minimal.The remaining components were less stressful.(2)The subject's medial tibial plateau anterior-posterior diameter length was 53 mm,and by calculating the ratio,the optimal ratio of tibial prosthesis riser length to anterior-posterior tibial diameter should be about 62%.If it is lower than this value,aseptic loosening of the prosthesis may occur,and if it is higher than this value,fracture of the bone cortex at the anterior-posterior end of the tibia may occur.

Objective    To systematically evaluate the risk factors for postoperative pulmonary infection in patients with esophageal cancer. Methods    CNKI, Wangfang Data, VIP, CBM, PubMed, EMbase, The Cochrane Library were searched from inception to January 2021 to collect case-control studies, cohort studies and cross-sectional studies about risk factors for postoperative pulmonary infection in patients with esophageal cancer. Two researchers independently conducted literature screening, data extraction and quality assessment. RevMan 5.3 software and Stata 15.0 software were used for meta-analysis. Results    A total of 20 articles were included, covering 5 409 patients of esophageal cancer. The quality score of included studies was 6-8 points. Meta-analysis results showed that age (MD=1.99, 95%CI 0.10 to 3.88, P=0.04), age≥60 years (OR=2.68, 95%CI 1.46 to 4.91, P=0.001), smoking history (OR=2.41, 95%CI 1.77 to 3.28, P<0.001), diabetes (OR=2.30, 95%CI 1.90 to 2.77, P<0.001), chronic obstructive pulmonary disease (OR=3.69, 95%CI 2.09 to 6.52, P<0.001), pulmonary disease (OR=2.22, 95%CI 1.16 to 4.26, P=0.02), thoracotomy (OR=1.77, 95%CI 1.32 to 2.37, P<0.001), operation time (MD=14.08, 95%CI 9.64 to 18.52, P<0.001), operation time>4 h (OR=3.09, 95%CI 1.46 to 6.55, P=0.003), single lung ventilation (OR=3.46, 95%CI 1.61 to 7.44, P=0.001), recurrent laryngeal nerve injury (OR=5.66, 95%CI 1.63 to 19.71, P=0.006), and no use of patient-controlled epidural analgesia (PCEA) (OR=2.81, 95%CI 1.71 to 4.61, P<0.001) were risk factors for postoperative pulmonary infection in patients with esophageal cancer. Conclusion    The existing evidence shows that age, age≥60 years, smoking history, diabetes, chronic obstructive pulmonary disease, pulmonary disease, thoracotomy, operation time, operation time>4 h, single lung ventilation, recurrent laryngeal nerve injury, and no use of PCEA are risk factors for postoperative pulmonary infection in patients with esophageal cancer. Due to the limitation of the quantity and quality of included literature, the conclusion of this study still needs to be confirmed by more high-quality studies.

In unicompartmental replacement surgery, there are a wide variety of commercially available unicompartmental prostheses, and the consistency of the contact surface between the common liner and the femoral prosthesis could impact the stress distribution in the knee after replacement in different ways. Medial tibial plateau fracture and liner dislocation are two common forms of failure after unicompartmental replacement. One of the reasons is the mismatch in the mounting position of the unicompartmental prosthesis in the knee joint, which may lead to failure. Therefore, this paper focuses on the influence of the shape of the contact surface between the liner and the femoral prosthesis and the mounting position of the unicompartmental prosthesis on the stress distribution in the knee joint after replacement. Firstly, a finite element model of the normal human knee joint was established, and the validity of the model was verified by both stress and displacement. Secondly, two different shapes of padded knee prosthesis models (type A and type B) were developed to simulate and analyze the stress distribution in the knee joint under single-leg stance with five internal or external rotation mounting positions of the two pads. The results showed that under a 1 kN axial load, the peak contact pressure of the liner, the peak ACL equivalent force, and the peak contact pressure of the lateral meniscus were smaller for type A than for type B. The liner displacement, peak contact pressure of the liner, peak tibial equivalent force, and peak ACL equivalent force were the smallest for type A at 3° of internal rotation in all five internal or external rotation mounting positions. For unicompartmental replacement, it is recommended that the choice of type A or type B liner for prosthetic internal rotation up to 6° should be combined with other factors of the patient for comprehensive analysis. In conclusion, the results of this paper may reduce the risk of liner dislocation and medial tibial plateau fracture after unicompartmental replacement, providing a biomechanical reference for unicompartmental prosthesis design.
Arthroplasty, Replacement, Knee/methods* ; Biomechanical Phenomena ; Finite Element Analysis ; Humans ; Knee Joint/surgery* ; Knee Prosthesis ; Tibia/surgery*