ObjectiveTo explore the mechanism by which modified Guishenwan alleviates inflammation in the rat model of polycystic ovary syndrome （PCOS） by regulating the mitogen-activated protein kinase （MAPK）/nuclear factor kappa B （NF-κB） pathway. MethodsAccording to the random number table method， 60 SPF female SD rats were randomized into a normal group （n=10） and a modeling group （n=50）. The normal group received routine feeding， while the modeling group was administrated with letrozole （1 mg·kg^-1·d^-1） by gavage for 21 days for the modeling of PCOS. The successfully modeled rats were randomized into model， diane-35 （0.2 g·kg^-1·d^-1）， high- （16.04 g·kg^-1·d^-1）， medium- （8.02 g·kg^-1·d^-1）， low- （4.01 g·kg^-1·d^-1） dose modified Guishenwan groups. The drug intervention groups were administrated with modified Guishenwan at corresponding doses by gavage， and the normal group and model group were given equal volumes of normal saline. All the groups were continuously treated for 28 days. After treatment， Gram staining of vaginal smears was employed to observe the estrous cycle in each group. Enzyme-linked immunosorbent assay was employed to determine the levels of follicle-stimulating hormone （FSH）， estradiol （E₂）， luteinizing hormone （LH）， testosterone （T）， and progesterone （PROG） in the plasma， as well as interleukin-1 beta （IL-1β）， tumor necrosis factor-alpha （TNF-α）， and interleukin-10 （IL-10） in the plasma and ovarian tissue. The LH/FSH ratio was calculated. The morphological changes in the ovarian tissue were observed by hematoxylin-eosin （HE） staining. Western blot was employed to determine the protein levels of extracellular-regulated protein kinase （ERK）， c-Jun N-terminal kinase （JNK）， p38 MAPK， NF-κB p65， IκBα， p-JNK， p-ERK， p-p38 MAPK， p-NF-κB p65， and p-IκBα in the ovarian tissue. Real-time quantitative polymerase chain reaction was used to determine the mRNA levels of ERK， JNK， p38 MAPK， NF-κB p65， and IκBα in the ovarian tissue. ResultsCompared with the normal group， the model group was in the estrus phase， with an increase in the number of ovarian vesicles and decreases in granulosa cells and corpus luteum formation （P<0.05）， and lowered levels of FSH and E₂ and elevated levels of LH， T， and LH/FSH in the plasma （P<0.05）. Compared with the model group， high-， medium-， and low-dose modified Guishenwan recovered the estrous cycle， increased the generation of granulosa cells and corpus luteum， reduced the number of vesicles， elevated the levels of FSH and E₂， and lowered the levels LH， T， and LH/FSH （P<0.05， P<0.01） in a dose-dependent manner. High-dose modified Guishenwan demonstrated the best therapeutic effect. Therefore， subsequent experiments for exploring the treatment mechanism were conducted in the normal group， model group， and high-dose modified Guishenwan group. The results showed that compared with the model group， high-dose modified Guishenwan lowered the levels of IL-1β， TNF-α， and IL-10 and elevated the level of IL-10 in the plasma and ovarian tissue （P<0.05， P<0.01）， down-regulated the protein levels of p-ERK， p-JNK， p-p38 MAPK， p-NF-κB p65， and p-IκBα， while up-regulating the protein level of IκBα （P<0.01）. At the same time， the mRNA levels of ERK， JNK， p38 MAPK， and NF-κB p65 in the high-dose modified Guishenwan group were down-regulated （P<0.05， P<0.01）. ConclusionModified Guishenwan can improve the ovarian function in rat model of PCOS induced by letrozole and has anti-inflammatory effects， which may be related to inhibition of the MAPK/NF-κB pathway.

ObjectiveBased on the adenosine 5'-monophosphate （AMP）-activated protein kinase/protein kinase B/nuclear factor erythroid 2-related factor 2 （AMPK/Akt/Nrf2） pathway， this study aims to explore the mechanism by which modified Guishenwan improves glucose and lipid metabolism and oxidative stress in polycystic ovary syndrome （PCOS） rats. MethodsA PCOS rat model was established by continuous oral administration of letrozole （1 mg·kg^-1·d^-1） for 21 days. Successfully modeled rats were randomly divided into a model group， a metformin group （0.25 g·kg^-1）， and low-， medium-， and high-dose modified Guishenwan groups （4.01， 8.02， and 16.04 g·kg^-1·d^-1）， with 8 rats in each group. Ten normal rats were assigned to the normal group. The drug groups were given their respective doses， while the normal and model groups were given an equal volume of normal saline. Intervention lasted for 4 weeks. Testosterone （T）， estradiol （E₂）， follicle-stimulating hormone （FSH）， and luteinizing hormone （LH） were measured by enzyme-linked immunosorbent assay （ELISA）， and the LH/FSH ratio was calculated. Fasting blood glucose （FPG）， fasting insulin （FINS）， triglyceride （TG）， and total cholesterol （TC） levels were measured using an automatic biochemical analyzer， and the insulin resistance index （HOMA-IR） and insulin sensitivity index （HOMA-ISI） were calculated. Oral glucose tolerance test （OGTT） and insulin tolerance test （ITT） were conducted. Malondialdehyde （MDA）， advanced glycation end products （AGEs）， and superoxide dismutase （SOD） levels in serum and ovarian tissue were measured using a chemical fluorescence method. Hematoxylin-eosin （HE） staining was used to assess ovarian tissue pathology. Real-time quantitative fluorescent polymerase chain reaction （Real-time PCR） and Western blot were used to measure the expression of AMPK/Akt/Nrf2 pathway-related genes and proteins in ovarian tissue. ResultsCompared with the normal group， the model group exhibited significantly increased levels of T， LH， LH/FSH， FPG， FINS， TG， TC， and HOMA-IR， while FSH， E₂， and HOMA-ISI were significantly decreased （P<0.05， P<0.01）. MDA and AGEs levels were significantly higher in both serum and ovarian tissue， and SOD levels were significantly reduced （P<0.05）. AMPK， Akt， and Nrf2 mRNA and protein expression in ovarian tissue was also significantly reduced （P<0.05）. The OGTT and ITT results showed significantly higher blood glucose levels at each time point （P<0.05， P<0.01）， with impaired glucose and insulin tolerance. Ovarian follicles showed polycystic changes， reduced corpus luteum， and sparse granulosa cell layers. Compared with the model group， the metformin group and the high-dose modified Guishenwan group showed significant decreases in T， LH， LH/FSH， FPG， FINS， TG， TC， and HOMA-IR， while FSH， E₂， and HOMA-ISI were significantly increased （P<0.05， P<0.01）. In the high-dose modified Guishenwan group， MDA and AGEs levels in serum and ovarian tissue were significantly reduced， and SOD levels were significantly increased （P<0.05）. The mRNA and protein expression of AMPK， Akt， and Nrf2 in ovarian tissue was significantly increased （P<0.05）. OGTT and ITT results showed that blood glucose levels in rats decreased significantly at each time point （P<0.05， P<0.01）. No obvious abnormalities were observed in ovarian tissue. Compared with the low-dose modified Guishenwan group， the high-dose group showed significant decreases in T， LH， LH/FSH， FPG， FINS， TG， TC， and HOMA-IR， while FSH， E₂， and HOMA-ISI were significantly increased （P<0.05）. OGTT and ITT results indicated that the high-dose modified Guishenwan group significantly improved glucose and insulin tolerance in rats. No significant abnormalities were observed in ovarian tissue. ConclusionModified Guishenwan effectively improves glucose and lipid metabolism abnormalities and inhibits oxidative stress in PCOS rats， potentially through regulation of the AMPK/Akt/Nrf2 pathway.

Objective To investigate the impact of quercetin(Que)on postherpetic neuralgia(PHN)and chemokine ligand 3(CCL3,namely MIP-1α)/C-C chemokine receptor 1(CCR1)/C-C chemokine receptor 5(CCR5)signaling pathway in rats.Methods Sixty rats were divided into the control group(Con),the PHN group(model group),the L-Que(30 mg/kg)group,the M-Que(60 mg/kg)group,the H-Que(120 mg/kg)group and the H-Que+pathway activator MIP-1α(120 mg/kg Que+0.4 mg/kg recombinant MIP-1α)group.The mechanical paw withdrawal threshold(PWT)and thermal pain threshold(TWL)of rats were detected in each group.The kit was used to detect adenosine,Adenine ribonucleotide(AMP),adenosine diphosphate(ADP)and tumor necrosis factor in spinal dorsal horn samples-α(TNF-α),and interleukin-1 β(IL-1 β)levels in spinal dorsal horn samples.HE staining was applied to observe the pathological sections of spinal dorsal horn.Immunofluorescence staining was used to detect the activation of microglia in spinal dorsal horn.Western blot assay was applied to detect MIP-1α/CCR1/CCR5 signaling pathway protein expression.Results In the PHN group,the dorsal horn of the spinal cord was ruptured,the arrangement of nerve bundles was disordered,and inflammatory cell infiltration,edema,and slight atrophy of neurons appeared.Compared with the Con group,the PWT value,adenosine,AMP and ADP levels were obviously decreased in the PHN group(P＜0.05),and TWL value,TNF-α,IL-1β levels,the number of Iba1-positive microglia,MIP-1α,CCR1 and CCR5 protein levels were obviously increased(P＜0.05).After treatment with Que,the disordered arrangement of nerve bundles was improved,the infiltration of inflammatory cells was reduced,and the phenomenon of neuronal atrophy disappeared.Compared with the PHN group,the PWT value,adenosine,AMP and ADP levels were obviously increased in the L-Que group,the M-Que group and the H-Que group(P＜0.05).TWL value,TNF-αand IL-1β levels,the number of Iba1-positive microglia,and MIP-1α,CCR1 and CCR5 protein levels were obviously decreased(P＜0.05).The effect of Que was dose dependent.Compared with the H-Que group,PWT value,adenosine,AMP and ADP levels were obviously decreased in the H-Que+MIP-1α group(P＜0.05),and TWL value,TNF-α,IL-1β levels,the number of Iba1 positive microglia,MIP-1α,CCR1 and CCR5 protein levels were obviously increased(P＜0.05).Conclusion Que may reduce the inflammatory response in rats by inhibiting the MIP-1α/CCR1/CCR5 signaling pathway,thereby reducing PHN.

OBJECTIVE To study the pharmacokinetic changes in the plasma and cerebrospinal fluid of bronchial asthma model rats after the complication of Ephedra sinica and Prunus armeniaca. METHODS SD male rats were randomly divided into blank group， model group， E. sinica group （12 g/kg， calculated by raw drug， similarly hereinafter）， P. armeniaca group （6 g/kg） and E. sinica-P. armeniaca drug-pair group （12 g/kg of E. sinica+6 g/kg of P. armeniaca）， with 6 rats in each group. Except for the blank group， the bronchial asthma model was induced by spraying rats in each group with an equal volume mixture of 2% acetylcholine chloride and 0.4% histamine phosphate， once a day， for 7 d. One hour before modeling every time， rats in each group were gavaged with the corresponding drug/normal saline， once a day， for 7 d. After the final administration and provocation of asthma， blood and cerebrospinal fluid collection were performed at different time points. The plasma and cerebrospinal fluid samples were pre-treated （with geranylgeranyl as the internal standard）， and the mass concentrations of ephedrine/pseudoephedrine， methyl ephedrine and amygdalin in both samples were determined by liquid chromatography-tandem mass spectrometry. DAS 2.0 pharmacokinetic software was used to determine the main pharmacokinetic parameters through the non-atrial chamber model and to compare the changes of the pharmacokinetic parameters before and after the combination of the two drugs. RESULTS Compared with E. sinica group， cmax and AUC0-21.33 h （or AUC0-10.67 h） of ephedrine/pseudoephedrine and methyl ephedrine in the plasma and cerebrospinal fluid of rats were significantly reduced in E. sinica-P. armeniaca drug-pair group， while CLZ/F and VZ/F were significantly increased （P＜0.05 or P＜0.01）； tmax of methyl ephedrine in the cerebrospinal fluid was significantly shortened （P＜ 0.05）.Compared with P. armeniaca group， the t1/2 of amygdalin in the plasma of rats in E. sinica-P. armeniaca drug-pair group was significantly shortened， and CLZ/F was significantly increased （P＜0.01）； the tmax of bitter amygdalin in the cerebrospinal fluid was significantly shortened， and the AUC0-10.67 h， CLZ/F， and VZ/F were significantly increased （P＜0.01）. CONCLUSIONS The combination of E. sinica and P. armeniaca accelerates the absorption and elimination of ephedra alkaloids， thus reducing the accumulation of ephedra alkaloids in the bronchial asthma model rats.

ObjectiveTo explore the association between short-term exposure to atmospheric fine particulate matter （PM_2.5） and ozone （O₃） and systemic inflammatory indicators in patients with pneumonia， and to identify the susceptible populations. MethodsFrom September 2018 to April 2020， data of 1 480 patients admitted for pneumonia was collected from a tertiary hospital in Taiyuan City. Generalized additive models （GAMs） were used to explore the associations between PM_2.5 and O₃ exposure and inflammatory indicators of patients with pneumonia； and to explore the susceptibility factors and susceptible populations to PM_2.5 and O₃ exposures through stratified analyses. ResultsThe short-term exposure to PM_2.5 was associated with changes in peripheral blood C-reation protein （CRP）， erythrocyte sedimentation （ESR）， easinophil （EOS）， neutrophil （NEU） and neutrophil-lymphocyte ratio （NLR） in patients with pneumonia， and there were different degrees of hysteresis effects， with the effect values reaching a maximum at lag03， lag03， lag0， lag03， lag03， respectively， which were 4.13% （95%CI： 0.43%‒7.84%）， 3.10% （95%CI： 0.24%‒5.97%）， 5.27% （95%CI： 3.12%‒7.42%）， 1.85% （95%CI： 0.36%‒3.34%）， and 2.53% （95%CI： 0.53%‒4.74%） for every 10 μg·m^-3 of PM_2.5. The changes in O₃ concentration were associated with the elevation of peripheral blood PCT and ESR in patients with pneumonia， and their effect values all reached the maximum at lag01 d， every 1 μg·m^-3 of O₃ elevation increased by 0.38% （95%CI： 0.04%‒0.73%） and 0.47% （95%CI： 0.19%‒0.76%）， respectively. Stratified analyses showed that the associations of PM_2.5 with peripheral blood CRP， ESR， NEU， and NLR in pneumonia patients were more significant in males， the elderly， and those with onset in the cold season； the associations of O₃ with peripheral blood PCT and ESR in pneumonia patients were more significant in the elderly and those with onset in the warm season， and the peripheral blood CRP and PCT in female patients with pneumonia were more susceptible to the changes of O₃. ConclusionShort-term exposure to atmospheric PM_2.5 and O₃ are positively associated with changes in inflammatory indicators in patients with pneumonia， and the effects of PM_2.5 on patients with pneumonia are more extensive than those of O₃， with a longer lag effect. In addition， elderly patients with pneumonia are more sensitive to air pollution， male patients with pneumonia are more sensitive to PM_2.5， and female patients with pneumonia are more sensitive to O₃. Cold and warm seasons can exacerbate the effects of PM_2.5 and O₃ on inflammatory indicators in patients with pneumonia， respectively， and the patients must be protected well.

Objective:To investigate the application effect of problem-based learning (PBL) combined with scenario simulation in nursing teaching of needlestick injuries.Methods:A total of 123 undergraduates majoring in nursing were selected as research subjects from the classes of 2020 and 2021 in a medical university. The 60 undergraduates in the class of 2020 were established as control group and were given PBL teaching, and the 63 undergraduates in the class of 2021 were established as experimental group and were given PBL combined with scenario simulation. The two groups were compared in terms of theoretical score, skill examination score, and knowledge-attitude-practice (KAP) score of needlestick injury knowledge. SPSS 25.0 was used to perform the t-test, the chi-square test, and the rank sum test. Results:Compared with the control group, the experimental group had significantly higher scores of theoretical examination [(84.43±5.03) vs. (80.30±4.81), P<0.001] and skill examination [(88.40±4.26) vs. (83.55±5.84), P<0.001], as well as significantly higher scores of knowledge [(14.46±1.03) vs. (13.18±1.23), P<0.001], attitude [(52.59±3.09) vs. (48.05±3.06), P<0.001], and practice [(67.37±4.28) vs. (62.17±3.92), P<0.001] in KAP questionnaire. Conclusions:PBL combined with scenario simulation teaching can effectively improve the knowledge of protection against needlestick injuries and related skills in nursing students, enhance their awareness of needlestick injuries, and promote the protective behavior against needlestick injuries.

Objective:To explore the risk factors of postoperative depression in patients with esophageal cancer, and to develop a risk prediction model which providing a theoretical basis for the early detection of depression in high-risk groups by clinical staff.Methods:From September 2022 to March 2023, at the South Campus of Affiliated Hospital of Jiangnan University, 269 hospitalized patients with esophageal cancer (191 in depression group, 78 in non-depression group) were selected as the model construction set. From March to May 2023, at the South Campus of Affiliated Hospital of Jiangnan University, 78 hospitalized patients with esophageal cancer were selected as the external validation set. The patients with Beck depression inventory-Ⅱ score ≥5 and depression diagnosed by two experts (chief psychiatrists of the Department of Psychiatry of Affiliated Hospital of Jiangnan University) were considered as depression and included in the depression group, and the other patients were enrolled in the non-depression group. The general data, blood routine examination, high-sensitivity C-reactive protein (hs-CRP), blood electrolytes, blood lipids, clinical symptoms (gastroesophageal reflux, sleep disturbance, appetite, etc.) and depression score were compared between the depression group and the non-depression group. Independent sample t-test and Mann-Whitney U test were used for statistical analysis. Multiple logistic regression model was performed to analyze the independent risk factors of postoperative depression in patients with esophageal cancer, and a risk warning model was constructed. The Hosmer-Lemeshow test and receiver operating characteristic curve (ROC) were used to evaluate the fitting degree and predictive efficiency of the model, and the cross-validation method was used to verify the effectiveness of the model. Results:The incidence of postoperative depression in patients with esophageal cancer was 71.0% (191/269). The total white blood cell count, hs-CRP, blood phosphorus β 2 microglobulin and the proportion of sleep disorders of the depression group were higher than those of the non-depression group (1.3 (1.1, 5.4) ×10 9/L vs. 0.9 (0.3, 1.1) ×10 9/L, 75.8 (54.8, 102.1) mg/L vs. 60.8 (3.6, 61.5) mg/L, (1.33±0.32) mmol/L vs. (1.02±0.19) mmol/L, (2.17±0.72) mg/L vs.(2.12±0.49) mg/L, 84.3% (161/191) vs. 33.3% (26/78), and the differences were statistically significant ( Z=9.24, 7.88, t=9.24, χ2=67.87 t=1.98; all P<0.001); hemoglobin, total platelet count, high-density lipoprotein (HDL) and the proportion of poor appetite were lower than those of the non-depression group ((119.91±24.51) g/L vs. (122.09±22.97) g/L, (203.43±58.45)×10 9/L vs. (311.55±83.54)×10 9/L, (1.04±0.30) mmol/L vs. (1.43±0.23) mmol/L, 73.3% (140/191) vs. 84.6% (66/78)), and the differences were statistically significant ( t=-2.00, -8.42 and -8.48, χ2=3.96; P=0.047, <0.001, <0.001, =0.047). The results of multifactorial logistic regression model analysis showed that sleep disorder ( OR=3.976, 95% confidence interval (95% CI 1.601 to 9.872)), loss of appetite ( OR=0.271, 95% CI 0.092 to 0.791), white blood cell count ( OR=31.808, 95% CI 2.879 to 351.401), hs-CRP ( OR=1.031, 95% CI 1.017 to 1.044), platelet count ( OR=0.990, 95% CI 0.982 to 0.997), and HDL ( OR=0.017, 95% CI 0.001 to 0.242) were independent influencing factors of postoperative depression in patients with esophageal cancer. The formula of risk warning model was probability of depression=1-1/{1+ exp[1.544+ 1.380×sleep disturbance (yes=1, no=0)-1.307×loss of appetite (yes=1, no=0)-0.010×platelet count (×10 9/L)-4.063×HDL (mmol/L)+ 0.030×hs-CRP (mg/L)+ 3.460×white blood cell count (×10 9/L)]}. The results of Hosmer-Lemeshow test showed that the model has a good fit ( χ2=2.01, P=0.981), with an area under the ROC of 0.949, a sensitivity of 0.874, and a specificity of 0.872. The cross-validation of the external validation set showed that the accuracy of the risk warning model was 67.9%. Conclusion:This study is a preliminary study on the risk warning model of postoperative depression in patients with esophageal cancer, which provides a novel approach for screening depression in patients with esophageal cancer after surgery.

Objective:To evaluate the effects of fine particle matter(PM2.5)and ozone(O3)com-bined exposure on adenosine triphosphate(ATP)amount and ATPase activities in nasal mucosa of Spra-gue Dawley(SD)rats.Methods:Twenty male SD rats were divided into control group(n=10)and exposure group(n=10)by random number table method.The rats were fed in the conventional clean environment and the air pollutant exposure system established by our team,respectively,and exposed for 208 d.During the exposure period,the concentrations of PM2 5 and O3 in the exposure system were moni-tored,and a comprehensive assessment of PM2 5 and O3 in the exposure system was conducted by combi-ning self-measurement and site data.On the 208 d of exposure,the core,liver,spleen,kidney,testis and other major organs and nasal mucosal tissues of the rats were harvested.Each organ was weighed and the organ coefficient calculated.The total amount of ATP was measured by bioluminescence,and the ac-tivities of Na+-K+-ATPase and Ca2+-ATPase were detected by spectrophotometry.The t test of two inde-pendent samples was used to compare the differences among the indicator groups.Results:From the 3rd week to the end of exposure duration,the body weight of the rats in the exposure group was higher than that in the control group(P＜0.05),and there was no significant difference in organ coefficients be-tween the two groups.The average daily PM2 5 concentration in the exposure group was(30.68±19.23)μg/m3,and the maximum 8 h ozone concentration(O3-8 h)was(82.45±35.81)μg/m3.The chemi-luminescence value(792.4±274.1)IU/L of ATP in nasal mucosa of the rats in the exposure group was lower than that in the control group(1 126.8±218.1)IU/L.The Na+-K+-ATPase activity(1.53±0.85)U/mg in nasal mucosa of the rats in the exposure group was lower than that in the control group(4.31±1.60)U/mg(P＜0.05).The protein content of nasal mucosa in the control group and the exposure group were(302.14±52.51)mg/L and(234.58±53.49)mg/L,respectively,and the ac-tivity of Ca2+-ATPase was(0.81±0.27)U/mg and(0.99±0.73)U/mg,respectively.There was no significant difference between the groups.Conclusion:The ability of power capacity decreased in the rat nasal mucossa under the sub-chronic low-concentration exposure of PM2 5 and O3.

Objective To observe the impact factors of the diagnostic accuracy of fine needle aspiration biopsy(FNAB)for papillary thyroid carcinoma(PTC).Methods Totally 468 patients with single PTC confirmed by postoperative pathology who underwent FNAB before surgery were enrolled.The impact of clinica,l ultrasonic and pathological features on the accuracy of FNAB diagnosis were analyzed.Results The accuracy of FNAB for diagnosing PTC was 71.37%(334/468).The maximum diameter and location of PTC were both impact factors of the diagnostic accuracy of FNAB.The maximum diameter of 0.7 cm was the optimal cutoff value of FNAB for diagnosing PTC,and the diagnostic accuracy of FNAB for PTC with the maximum diameter＜0.7 cm and those≥0.7 cm was 62.96%(119/189)and 77.06%(215/279),respectively.The diagnostic accuracy of FNAB for PTC located in the difficult and easy area of puncture was 52.53%(52/99)and 76.42%(282/369),respectively.The diagnostic accuracy of FNAB for PTC with the maximum diameter≥0.7 cm and located in the easy area,≥0.7 cm and located in the difficult area,＜0.7 cm and located in the easy area,＜0.7 cm and located in the difficult area was 80.43%(185/230),61.22%(30/49),69.78%(97/139)and 44.00%(22/50),respectively.Conclusion The maximum diameter and location of PTC were both impact factors of the diagnostic accuracy of FNAB.

Objective:To evaluate the effect of continuous positive airway pressure (CPAP) ventilation during induction of anesthesia on perioperative atelectasis and oxygenation in elderly patients.Methods:Forty-six elderly patients of either sex, aged 65-80 yr, of American Society of Anesthesiologists Physical Status classification Ⅱ or Ⅲ, undergoing elective cerebrovascular intervention surgery under general anesthesia, were divided into 2 groups ( n=23 each) according to the random number table method: control group (group C) and CPAP ventilation group (group CPAP). During induction of anesthesia, CPAP was set at 5 cmH 2O during spontaneous breathing, and PEEP was set at 5 cmH 2O when spontaneous breathing disappeared, and the ventilation mode was changed to pressure-controlled ventilation (PCV) mode in group CPAP. CPAP was not set, and PEEP was set at 0 cmH 2O for PCV when spontaneous breathing disappeared in group C. During anesthesia maintenance, PCV-volume guaranteed mode was used in both groups, and PEEP was set at 5 cmH 2O. Whole lung CT scanning was performed immediately after radial artery catheterization (T 0), at 1 min after endotracheal intubation (T 1), and before tracheal extubation (T 2) at the end of operation to calculate the percentage of atelectasis area at 1 cm above the right diaphragm. At T 0, T 1, T 2 and 30 min after entering postanesthesia care unit (T 3), blood samples from the radial artery were taken to record PaO 2 and PaCO 2 and calculate the oxygenation index (OI). Results:Compared with the baseline at T 0, the percentage of atelectasis area was significantly increased at T 1 and T 2 in two groups ( P<0.05); PaO 2 was significantly increased at T 1 and T 2 and decreased to T 0 level at T 3, OI was decreased at T 1 and T 2 and increased to T 0 level at T 3 in two groups ( P<0.05). Compared with group C, the percentage of atelectasis area was significantly decreased and PaO 2 and OI were increased at T 1 and T 2 in group CPAP ( P<0.05). There was no significant difference in PaCO 2 at each time point between the two groups ( P>0.05). Conclusions:CPAP ventilation during induction of anesthesia can reduce the development of perioperative atelectasis and improve the oxygenation in elderly patients.