Objective:To report the results of national surveillance on the distribution and antimicrobial resistance profile of clinical Gram-negative bacteria isolates from bloodstream infections in China in 2022.Methods:The clinical isolates of Gram-negative bacteria from blood cultures in member hospitals of national bloodstream infection Bacterial Resistant Investigation Collaborative System（BRICS）were collected during January 2022 to December 2022. Antibiotic susceptibility tests were conducted by agar dilution or broth dilution methods recommended by Clinical and Laboratory Standards Institute（CLSI）. WHONET 5.6 and SPSS 25.0 software were used to analyze the data.Results:During the study period，9 035 strains of Gram-negative bacteria were collected from 51 hospitals，of which 7 895（87.4%）were Enterobacteriaceae and 1 140（12.6%）were non-fermenting bacteria. The top 5 bacterial species were Escherichia coli（ n=4 510，49.9%）， Klebsiella pneumoniae（ n=2 340，25.9%）， Pseudomonas aeruginosa（ n=534，5.9%）， Acinetobacter baumannii complex（ n=405，4.5%）and Enterobacter cloacae（ n=327，3.6%）. The ESBLs-producing rates in Escherichia coli， Klebsiella pneumoniae and Proteus spp. were 47.1%（2 095/4 452），21.0%（427/2 033）and 41.1%（58/141），respectively. The prevalence of carbapenem-resistant Escherichia coli（CREC）and carbapenem-resistant Klebsiella pneumoniae（CRKP）were 1.3%（58/4 510）and 13.1%（307/2 340）；62.1%（36/58）and 9.8%（30/307）of CREC and CRKP were resistant to ceftazidime/avibactam combination，respectively. The prevalence of carbapenem-resistant Acinetobacter baumannii（CRAB）complex was 59.5%（241/405），while less than 5% of Acinetobacter baumannii complex was resistant to tigecycline and polymyxin B. The prevalence of carbapenem-resistant Pseudomonas aeruginosa（CRPA）was 18.4%（98/534）. There were differences in the composition ratio of Gram-negative bacteria in bloodstream infections and the prevalence of main Gram-negative bacteria resistance among different regions，with statistically significant differences in the prevalence of CRKP and CRPA（ χ2=20.489 and 20.252， P<0.001）. The prevalence of CREC，CRKP，CRPA，CRAB，ESBLs-producing Escherichia coli and Klebsiella pneumoniae were higher in provinicial hospitals than those in municipal hospitals（ χ2=11.953，81.183，10.404，5.915，12.415 and 6.459， P<0.01 or <0.05），while the prevalence of CRPA was higher in economically developed regions（per capita GDP ≥ 92 059 Yuan）than that in economically less-developed regions（per capita GDP <92 059 Yuan）（ χ2=6.240， P=0.012）. Conclusions:The proportion of Gram-negative bacteria in bloodstream infections shows an increasing trend，and Escherichia coli is ranked in the top，while the trend of CRKP decreases continuously with time. Decreasing trends are noted in ESBLs-producing Escherichia coli and Klebsiella pneumoniae. Low prevalence of carbapenem resistance in Escherichia coli and high prevalence in CRAB complex have been observed. The composition ratio and antibacterial spectrum of bloodstream infections in different regions of China are slightly different，and the proportion of main drug resistant bacteria in provincial hospitals is higher than those in municipal hospitals.

Objective:To report the results of national surveillance on the distribution and antimicrobial resistance profile of clinical Gram-positive bacteria isolates from bloodstream infections in China in 2022.Methods:The clinical isolates of Gram-positive bacteria from blood cultures in member hospitals of National Bloodstream Infection Bacterial Resistant Investigation Collaborative System（BRICS）were collected during January 2022 to December 2022. Antibiotic susceptibility tests were conducted by agar dilution or broth dilution methods recommended by Clinical and Laboratory Standards Institute（CLSI）. WHONET 5.6 and SPSS 25.0 software were used to analyze the data.Results:A total of 3 163 strains of Gram-positive pathogens were collected from 51 member units，and the top five bacteria were Staphylococcus aureus（ n=1 147，36.3%），coagulase-negative Staphylococci（ n=928，29.3%）， Enterococcus faecalis（ n=369，11.7%）， Enterococcus faecium（ n=296，9.4%）and alpha-hemolyticus Streptococci（ n=192，6.1%）. The detection rates of methicillin-resistant Staphylococcus aureus（MRSA）and methicillin-resistant coagulase-negative Staphylococci（MRCNS）were 26.4%（303/1 147）and 66.7%（619/928），respectively. No glycopeptide and daptomycin-resistant Staphylococci were detected. The sensitivity rates of Staphylococcus aureus to cefpirome，rifampin，compound sulfamethoxazole，linezolid，minocycline and tigecycline were all >95.0%. Enterococcus faecium was more prevalent than Enterococcus faecalis. The resistance rates of Enterococcus faecium to vancomycin and teicoplanin were both 0.5%（2/369），and no vancomycin-resistant Enterococcus faecium was detected. The detection rate of MRSA in southern China was significantly lower than that in other regions（ χ2=14.578， P=0.002），while the detection rate of MRCNS in northern China was significantly higher than that in other regions（ χ2=15.195， P=0.002）. The detection rates of MRSA and MRCNS in provincial hospitals were higher than those in municipal hospitals（ χ2=13.519 and 12.136， P<0.001）. The detection rates of MRSA and MRCNS in economically more advanced regions（per capita GDP≥92 059 Yuan in 2022）were higher than those in economically less advanced regions（per capita GDP<92 059 Yuan）（ χ2=9.969 and 7.606， P=0.002和0.006）. Conclusions:Among the Gram-positive pathogens causing bloodstream infections in China， Staphylococci is the most common while the MRSA incidence decreases continuously with time；the detection rate of Enterococcus faecium exceeds that of Enterococcus faecalis. The overall prevalence of vancomycin-resistant Enterococci is still at a low level. The composition ratio of Gram-positive pathogens and resistant profiles varies slightly across regions of China，with the prevalence of MRSA and MRCNS being more pronounced in provincial hospitals and areas with a per capita GDP≥92 059 yuan.

Objective:To discuss the association between occupational acid fog exposure and accelerated biological aging of the workers,and to clarify its related risk factors.Methods:A total of 341 male workers exposed to occupational acid fog and 201 male workers without occupational exposure were selected as the study subjects,and they were divided into exposure group and control group,respectively.The general informations of the subjects in two groups were collected through questionnaires and physical examinations.The levels of red blood cell count(RBC),platelet count(PLT),albumin(ALB),urea(Urea),creatinine(CR),triglycerides(TG),total cholesterol(TC),glycated hemoglobin(HBA1c),and high-sensitivity C-reactive protein(Hs-CRP)in serum of the subjects in two groups were detected.The Klemera-Doubal method(KDM)was used to construct the composite aging measure,KDM-biological age(BA)(KDM-BA).The model parameters were trained using samples from the 2009 China Health and Nutrition Survey(CHNS)Database to calculate the BA acceleration of the subjects in two groups;stratified analysis based on the population characteristics was conducted to analyze the BA of the subjects in two groups with different population characteristics;generalized linear model was used to analyze the factors influencing BA acceleration due to acid fog exposure.Results:The model parameters were trained using samples from the 2009 CHNS Database,including 8 133 cases aged 20-79 years,of which 3 788 were male.The levels of Urea,CR,HBA1c,ALB,and TC,as well as systolic blood pressure(SBP),total working years,sleep duration,and body mass index(BMI)of the subjects between two groups had significant differences(P<0.05).Compared with control group,the BA acceleration of the subjects in exposure group was significantly increased(P<0.05).In entire population and exposure group,the BA acceleration in the smokers was significantly higher than that in the non-smokers(P<0.05).In entire population,control group,and exposure group,the BA accelerations of the subjects in different BMI groups were significantly decreased with the increase of BMI(P<0.05).Compared with control group,the BA acceleration of the subjects in exposure group was significantly increased(P<0.05),including those under 40 years old,with total working years of 4-7 years,Han nationality,unmarried,smokers,and sleep duration 6-7 h,and with overweight.Acid fog exposure,smoking,and BMI were associated with the BA acceleration(β=0.72,95%CI:0.24-1.21;β=0.59,95%CI:0.11-1.06;β=-0.29,95%CI:-0.35—-0.22).Conclusion:Occupational acid fog exposure may accelerate the biological aging in the workers,and acid fog is a risk factor to accelerate the biological aging of the body.

Objective To investigate the effect of different doses of esketamine combined with hydromorphone postoperative patient-controlled intravenous analgesia(PCIA)on depression in elderly pa-tients undergoing total knee arthroplasty.Methods A total of 180 elderly patients,44 males and 136 fe-males,aged 65-80 years,BMI 18.5-35.0 kg/m2,ASA physical status Ⅱ or Ⅲ,undergoing total knee arthroplasty(TKA)under elective general anesthesia combined with adductor block from J uly 2023 to Sep-tember 2023.Patients were divided into three groups by random number table method;control group(group C),esketamine 0.5 mg/kg group(group E1),and esketamine 1.0 mg/kg group(group E2),60 patients in each group.After operation,groups C,E1 and E2 were given hydromorphone 0.2 mg/kg,esketamine 0.5 mg/kg combined with hydromorphone 0.2 mg/kg,and esketamine 1.0 mg/kg combined with hydromor-phone 0.2 mg/kg to receive PCIA,respectively,and the three groups were diluted to 100 ml with normal saline.Parameters were set as follows.The background infusion rate was 1.5 ml/h,and the single press dose was 1.5 ml,and the locking time was 15 minutes.If the VAS pain score at rest was greater than or equal to 4 points and the analgesic effect of pressing the PCIA pump was not effective,then intramuscular injection of tramadol 0.1 g was used for remedial analgesia.Hamilton depression scale(HAMD)score was performed 1 day,3 and 7 days after surgery.Depressive state was classified as having HAMD score ≥ 8 points.VAS pain scores at rest were performed 1 day,3 and 7 days after surgery.The number of depression within 7 days after surgery,the number of effective(D1)and total(D2)pump compressions and D1/D2 within 3 days after surgery,the number of rescue analgesia,the occurrence of adverse reactions such as tra-madol dosage,dizziness,headache,multiple dreams,hallucinations,nausea and vomiting were recorded.Results Twenty-one patients(35％)in group C experienced depression,7 patients(12％)in group E1,and 8 patients(13％)in group E2 during 3 days after surgery.Eight patients(13％)in group C experi-enced depression,1 patients(2％)in group E1,and 2 patients(3％)in group E2 during 7 days after sur-gery.Compared with group C,the incidence of depression 3 and 7 days after surgery,rescue analgesia rate in group E1 were significantly decreased,the incidence of depression 3 and 7 days after surgery,dizziness,headache,and dreaminess within 3 days after surgery in group E2 were significantly decreased(P＜0.05).There were no significant differences in the incidence of depression and VAS pain scores between group El and group E2 at 1,3,and 7 days after surgery.Conclusion Esketamine 0.5 and 1.0 mg/kg for PCIA in elderly patients after TKA can improve postoperative depression,while esketamine 1.0 mg/kg can reduce the incidence of postoperative dizziness,headache,and multiple dreams.

This study aims to gain insight into the DNA-specific recognition mechanism of c-Myb transcription factor during the regulation of cell early differentiation and proliferation. Therefore, we chose the chicken myeloid gene, mitochondrial import protein 1 (mim-1), as a target to study the binding specificity between potential dual-Myb-binding sites. The c-Myb-binding site in mim-1 is a pseudo-palindromic sequence AACGGTT, which contains two AACNG consensuses. Simulation studies in different biological scenarios revealed that c-Myb binding with mim-1 in the forward strand (complex F) ismore stable than that inthereverse strand (complex R). The principal component analysis (PCA) dynamics trajectory analyses suggested an opening motion of the recognition helices of R2 and R3 (R2R3), resulting in the dissociation of DNA from c-Myb in complex R at 330 K, triggered by the reduced electrostatic potential on the surface of R2R3. Furthermore, the DNA confirmation and hydrogen-bond interaction analyses indicated that the major groove width of DNA increased in complex R, which affected on the hydrogen-bond formation ability between R2R3 and DNA, and directly resulted in the dissociation of DNA from R2R3. The steered molecular dynamics (SMD) simulation studies also suggested that the electrostatic potential, major groove width, and hydrogen bonds made major contribution to the DNA‍-specific recognition. In vitro trials confirmed the simulation results that c-Myb specifically bound to mim-1 in the forward strand. This study indicates that the three-dimensional (3D) structure features play an important role in the DNA-specific recognition mechanism by c-Myb besides the AACNG consensuses, which is beneficial to understanding the cell early differentiation and proliferation regulated by c-Myb, as well as the prediction of novel c-Myb-binding motifs in tumorigenesis.
Molecular Dynamics Simulation ; Consensus ; DNA ; Hydrogen

Objective:To understand and explore the incidence and influencing factors of malnutrition in patients with inflammatory bowel disease.Methods:This study was a cross-sectional study. Patients with inflammatory bowel disease hospitalized in the Department of Gastroenterology of a tertiary hospital in Shenzhen from March 1 to August 31, 2021 were enrolled. Indicators related to nutrition and clinical outcome were collected, including height, weight, body mass index (BMI), nutritional risk screening (NRS 2002) results, malnutrition diagnosis as per Global Leadership Initiative on Malnutrition (GLIM) criteria and Pittsburgh Sleep Quality Index (PSQI). Chi-square test, t-test and Wilcoxon rank sum test were used as appropriate for univariate analysis, and binary logistic regression analysis was used for multivariate analysis.Results:A total of 188 patients were included in this survey. There were 145 (77.1%) patients with no malnutrition, 38 (20.2%) with moderate malnutrition, and 5 (2.7%) with severe malnutrition according to GLIM criteria. In the subgroup of 47 ulcerative colitis patients, 12 (25.5%) were with moderate malnutrition and 3 (3.4%) were with severe malnutrition. In the subgroup of 141 Crohn's disease patients, 26 (18.4%) were with moderate malnutrition and 2 (1.4%) were with severe malnutrition. When divided by the presence or absence of malnutrition, there were statistically significant differences in age ( t = -2.237, P = 0.026), disease stage ( χ 2 = 22.299, P < 0.001), history of digestive tract resection ( χ 2 = 6.890, P = 0.009), intestinal infection ( χ 2 = 4.010, P = 0.045), gastrointestinal symptoms ( χ 2 =11.884, P = 0.001), hemoglobin ( t = 5.160, P < 0.001), serum albumin ( t = 3.96, P < 0.001), prealbumin ( t = 5.061, P < 0.001) and PSQI scores ( t = -4.744, P < 0.001). Multivariate analysis showed that the stage of disease, history of partial resection of digestive tract, gastrointestinal symptoms, hemoglobin, prealbumin and PSQI scores were the main influencing factors of malnutrition. Conclusions:IBD patients at older age, at active stage, and with history of partial digestive tract resection, intestinal infection, gastrointestinal symptoms, low hemoglobin, low serum albumin, low prealbumin and poor sleep quality are more likely to develop malnutrition. Timely intervention should be carried out to improve the nutritional status of these patients.

Objective:To report the results of national surveillance on the distribution and antimicrobial resistance profile of clinical bacterial isolates from bloodstream infections in China in 2021.Methods:The clinical bacterial strains isolated from blood culture from member hospitals of Blood Bacterial Resistant Investigation Collaborative System (BRICS) were collected during January 2021 to December 2021. Antibiotic susceptibility tests were conducted by agar dilution or broth dilution methods recommended by Clinical Laboratory Standards Institute (CLSI). WHONET 5.6 was used to analyze data.Results:During the study period, 11 013 bacterial strains were collected from 51 hospitals, of which 2 782 (25.3%) were Gram-positive bacteria and 8 231 (74.7%) were Gram-negative bacteria. The top 10 bacterial species were Escherichia coli (37.6%), Klebsiella pneumoniae (18.9%), Staphylococcus aureus (9.8%), coagulase-negative Staphylococci (6.3%), Pseudomonas aeruginosa (3.6%), Enterococcus faecium (3.6%), Acinetobacter baumannii (2.8%), Enterococcus faecalis (2.7%), Enterobacter cloacae (2.5%) and Klebsiella spp (2.1%). The prevalence of methicillin-resistant Staphylococcus aureus (MRSA) and methicillin-resistant coagulase-negative Staphylococcus aureus were 25.3% and 76.8%, respectively. No glycopeptide- and daptomycin-resistant Staphylococci was detected; more than 95.0% of Staphylococcus aureus were sensitive to ceftobiprole. No vancomycin-resistant Enterococci strains were detected. The rates of extended spectrum B-lactamase (ESBL)-producing isolated in Escherichia coli, Klebsiella pneumoniae and Proteus mirabilis were 49.6%, 25.5% and 39.0%, respectively. The prevalence rates of carbapenem-resistance in Escherichia coli and Klebsiella pneumoniae were 2.2% and 15.8%, respectively; 7.9% of carbapenem-resistant Klebsiella pneumoniae was resistant to ceftazidime/avibactam combination. Ceftobiprole demonstrated excellent activity against non-ESBL-producing Escherichia coli and Klebsiella pneumoniae. Aztreonam/avibactam was highly active against carbapenem-resistant Escherichia coli and Klebsiella pneumoniae. The prevalence rate of carbapenem-resistance in Acinetobacter baumannii was 60.0%, while polymyxin and tigecycline showed good activity against Acinetobacter baumannii (5.5% and 4.5%). The prevalence of carbapenem-resistance in Pseudomonas aeruginosa was 18.9%. Conclusions:The BRICS surveillance results in 2021 shows that the main pathogens of blood stream infection in China are gram-negative bacteria, in which Escherichia coli is the most common. The MRSA incidence shows a further decreasing trend in China and the overall prevalence of vancomycin-resistant Enterococci is low. The prevalence of Carbapenem-resistant Klebsiella pneumoniae is still on a high level, but the trend is downwards.

Objective:To evaluate the effect of esketamine on extremity ischemia-reperfusion-induced lung injury in elderly patients undergoing total knee replacement.Methods:Sixty elderly patients of both sexes, aged 65-80 yr, with body mass index <35 kg/m 2, of American Society of Anesthesiologists Physical Status classification Ⅱ or Ⅲ, scheduled for elective unilateral total knee replacement under neuraxial anesthesia, were divided into 2 groups according to the random number table method: control group (C group) and esketamine group (S group), with 30 cases in each group. Esketamine 0.3 mg/kg was intravenously infused before tourniquet inflation in group S. Immediately after the end of operation, the two groups received adductor block with 0.5% ropivacaine 15 ml under ultrasound guidance. And then patient-controlled intravenous analgesia was performed, patient-controlled intravenous analgesia solution included sufentanil 1.5 μg/kg in 100 ml of normal saline in group C and sufentanil 1.5 μg/kg and esketamine 0.75 mg/kg in 100 ml of normal saline in group S. The background infusion rate was 1.5 ml/h, the patient-controlled analgesia dose was 1.5 ml, and the lockout interval was 15 min in the two groups. When the visual analogue scale score at rest≥ 4 points within 3 days after surgery, ketorolac tromethamine 30 mg was intravenously injected for rescue analgesia. Blood samples from the radial artery were collected for blood gas analysis at 30 min before tourniquet inflation(T 0), 30 min after tourniquet inflation(T 1), and 3 min, 30 min and 24 h (T 4) after tourniquet release (T 2-4), and PaO 2 and PaCO 2 were recorded. The alveola-arterial oxygen partial pressure difference, oxygenation index and respiratory index were calculated. Peripheral venous blood samples were collected at T 0, T 3 and T 4 for determination of serum endothelin-1 and malondialdehyde by enzyme-linked immunosorbent assay. The requirement for rescue analgesia and occurrence of dizziness, hallucinations and pulmonary complications within 3 days after surgery were recorded. Results:Compared with group C, alveola-arterial oxygen partial pressure difference was significantly decreased at T 1-3, respiratory index was decreased, oxygenation index was increased at T 2, 3, and serum endothelin-1 and malondialdehyde concentrations were decreased at T 3, 4, and the rate of postoperative rescue analgesia was decreased in group S( P<0.05). There was no significant difference in the incidence of postoperative dizziness, hallucinations, and pulmonary complications between the two groups ( P>0.05). Conclusions:Esketamine can reduce extremity ischemia-reperfusion-induced lung injury in elderly patients undergoing total knee replacement, and the mechanism may be related to regulating vascular endothelial function and reducing lipid peroxidation.

The clinical features, laboratory tests, imaging findings, treatment and outcomes of 26 non-HIV infection patients with Pneumocystis jirovecii pneumonia (PJP) diagnosed in our hospital from January 2017 to February 2022 were retrospectively analyzed. There were 19 males and 7 females, with an average age of 44(30, 51)years. All patients had underlying diseases of immunosuppression. The main symptoms included fever in 18 cases (69.2%), cough in 15 cases (57.7%), shortness of breath in 11 cases(42.3%). The laboratory test results showed elevated levels of CRP in 22 cases (95.7%), PCT in 18 cases (78.3%), lactate dehydrogenase in 17 cases (17/19), G test in 14 cases (14/20), and decreased CD4 +T cell count in 14 cases (14/19). Pneumocystis jirovecii pathogen was detected in bronchoalveolar lavage fluid in 16 cases (61.5%), in blood samples in 10 cases (38.5%). Pneumocystis jirovecii was not detected in sputum or bronchoalveolar lavage fluid using smear microscopy. Chest CT showed ground-glass opacity in 25 cases (96.1%). All patients received compound sulfamethoxazole tablet, 21 patients (80.8%) were also treated with other anti-fungal drugs. Among the 26 patients, 1 case (3.9%) received extra-corporeal membrane oxygenation (ECMO), 5 cases (19.2%) received non-invasive ventilation, 7 cases (27.0%) received invasive ventilation, and 13 cases (50.0%) received nasal cannula oxygen therapy. Of the 26 cases, 19 cases(73.1%)developed severe pneumonia. Finally, 21 patients (80.8%) improved and discharged, and 5 patients (19.2%) died. In conclusion, non-HIV infection patients with Pneumocystis jirovecii pneumonia were mainly middle-aged or elderly people with underlying diseases of immunosuppression. The clinical symptoms are mainly fever, cough, and shortness of breath. The imaging manifestations are mainly ground-glass opacity and consolidation opacity. Laboratory tests show elevated CRP, PCT, LDH, and G tests, and decreased CD4 +T cells. Compound sulfamethoxazole-based comprehensive treatment is effective for PJP. The disease is characterized by high proportion of severe pneumonia, fast remission and high risk of mortality.

Objective:To explore the application value of two-dimensional speckle tracking imaging (2D-STI) in evaluating diaphragm function, and to compare the ability of 2D-STI and conventional diaphragm ultrasonography in diagnosing diaphragmatic dysfunction and evaluating disease severity in patients with acute exacerbation of chronic obstructive pulmonary disease (AECOPD).Methods:A total of 58 AECOPD patients admitted to the First Affiliated Hospital of Xi′an Jiaotong University from January to October 2021 were retrospectively enrolled as AECOPD group, and 34 healthy subjects were recruited as control group during the same period. Repeatability test of diaphragmatic 2D-STI was performed. According to modified Medical Research Council (mMRC) dyspnea scores system and COPD Assessment Test (CAT), mMRC 0-1 and CAT<10 was classified as group A, mMRC≥2 and CAT≥10 was classified as group B. The baseline characteristics, conventional diaphragm ultrasonography parameters(thickening fraction and excursion) and 2D-STI parameters (longitudinal and radial strains) were compared between the AECOPD group and the control group, and the Spearman correlation between parameters of AECOPD group and forced expiratory volume in one second (FEV1) was analyzed. The differences of these parameters between group A and B were also compared. The ROC curve of conventional diaphragm ultrasonography parameters and 2D-STI parameters was plotted to differentiate group A from group B, and the diagnostic efficacy was evaluated.Results:Great intra- and inter-observer reproducibility was found for all diaphragmatic 2D-STI parameters, with ICCs above 0.80 for all measurements. The control group and the AECOPD group did not differ in age, sex and body mass index( P>0.05), whereas there were significant differences in smoking history, lung function, bilateral thickening fraction, excursion, longitudinal and radial strains( P<0.05). Compared with control group, patients in group A had a significant increase in diaphragm thickness ( P<0.05), while there was no significant difference in that between group B and control group ( P>0.05). The bilateral longitudinal strains, radial strains and thickening fraction of diaphragm were linearly correlated with FEV1 (right side rs=0.828, 0.794, 0.843, respectively; all P<0.001; left side rs=0.757, 0.704, 0.752, respectively; all P<0.001 ), while the correlation between excursion and FEV1 was not significant(right side rs=0.247, left side rs=0.253; all P>0.05). There were significant differences in bilateral longitudinal strains, radial strains and thickening fraction between group A and group B(all P<0.05), whereas there was no significant difference in excursion between the two groups ( P>0.05). ROC analysis showed bilateral longitudinal and radial strains had higher accuracy in distinguishing group A from group B than thickening fraction and excursion(right side AUCs 0.90, 0.84, 0.78 and 0.62, respectively; left side AUCs 0.85, 0.83, 0.77 and 0.62, respectively). Conclusions:2D-STI is a real-time noninvasive technique for diaphragm function assessment, which has high clinical value. Compared with conventional ultrasonography, 2D-STI shows more accuracy and effectiveness in diagnosing diaphragmatic dysfunction and evaluating disease severity of patients with AECOPD.