Background::Substantial progress in air pollution control has brought considerable health benefits in China, but little is known about the spatio-temporal trends of economic burden from air pollution. This study aimed to explore their spatio-temporal features of disease burden from air pollution in China to provide policy recommendations for efficiently reducing the air pollution and related disease burden in an era of a growing economy.Methods::Using the Global Burden of Disease method and willingness to pay method, we estimated fine particulate matter (PM 2.5) and/or ozone (O 3) related premature mortality and its economic burden across China, and explored their spatio-temporal trends between 2005 and 2017. Results::In 2017, we estimated that the premature mortality and economic burden related to the two pollutants were RMB 0.94 million (68.49 per 100,000) and 1170.31 billion yuan (1.41% of the national gross domestic product [GDP]), respectively. From 2005 to 2017, the total premature mortality was decreasing with the air quality improvement, but the economic burden was increasing along with the economic growth. And the economic growth has contributed more to the growth of economic costs than the economic burden decrease brought by the air quality improvement. The premature mortality and economic burden from O 3 in the total loss from the two pollutants was substantially lower than that of PM 2.5, but it was rapidly growing. The O 3-contribution was highest in the Yangtze River Delta region, the Fen-Wei Plain region, and some western regions. The proportion of economic burden from PM 2.5 and O 3 to GDP significantly declined from 2005 to 2017 and showed a decreasing trend pattern from northeast to southwest. Conclusion::The disease burden from O 3 is lower than that of PM 2.5, the O 3-contribution has a significantly increasing trend with the growth of economy and O 3 concentration.

Objective:To analyze the duration of the second stage of labor without epidural anesthesia and its association with pregnancy outcome.Methods:This retrospective study involved 12 789 women who delivered without epidural anesthesia in the First Affiliated Hospital of Kunming Medical University from January 1, 2014 to December 31, 2017. These subjects were divided into primipara group (9 517 cases) and multipara group (3 272 cases). Demographic characteristics, maternal and neonatal outcomes and the duration of the second stage of labor were compared between the two groups using two independent samples t-test, Mann-Whitney U test and Chi-square test (Fisher's exact test). Differences in the maternal and neonatal outcomes were also analyzed among different subgroups in primiparae [length of second stage: <1 h group ( n=6 265), ≥1-2 h group ( n=2 305), ≥2-3 h group ( n=831) and ≥3 h group ( n=116)] and multiparae [length of second stage <1 h group ( n=3 144), ≥1-2 h group ( n=102) and ≥2 h group ( n=26)]. The association between second stage length and pregnancy outcomes was analyzed with Cramer's V. After adjusted for maternal age, gestational weeks at delivery, body mass index before pregnancy, complications during pregnancy and neonatal birth weight, the relationship between the duration of the second stage and adverse outcomes was analyzed by binary logistic regression analysis. Results:The 95 th percentile of the second-stage labor duration was 143 min for primiparae and 52 min for multiparae. The rates of vaginal delivery, forceps delivery, cesarean section in the second stage, episiotomy, third- or fourth-degree perineal laceration, postpartum hemorrhage, grade Ⅱ postpartum hemorrhage, transfusion, umbilical arterial blood gas pH<7.15 and transferring to neonatal intensive care unit (NICU) were all correlated with the duration of second stage in primiparae (Cramer's V values: 0.22, 0.23, 0.03, 0.22, 0.05, 0.10, 0.03, 0.03, 0.03 and 0.07, respectively, all P<0.05), and so did those of vaginal delivery, forceps delivery, episiotomy, postpartum hemorrhage, grade Ⅱ postpartum hemorrhage, transfusion and transferring to NICU in multiparae (Cramer's V values: 0.18, 0.19, 0.28, 0.14, 0.09, 0.13 and 0.06, respectively, all P<0.05). Logistic analysis showed that in primiparae, the duration of second stage >1 h was an independent risk factor for episiotomy, third- or fourth-degree perineum laceration, forceps delivery, postpartum hemorrhage, admission to NICU and umbilical arterial blood gas pH<7.15 [adjusted OR (95% CI): 2.080 (1.907-2.268), 1.773 (1.080-2.911), 1.625 (1.420-1.859), 1.365 (1.231- 1.514), 1.305 (1.165-1.462) and 1.246 (1.081-1.436), respectively], while second stage length >2 h was the independent risk factor for episiotomy, forceps delivery, third- or fourth-degree perineum laceration, postpartum hemorrhage, grade Ⅱ postpartum hemorrhage, blood transfusion, admission to NICU and umbilical arterial blood gas pH<7.15 [adjusted OR (95% CI): 4.844 (4.132-5.678), 4.223 (3.571-4.993), 3.289 (1.806-5.989), 1.952 (1.675-2.274), 1.781 (1.057-3.001), 1.654 (1.025-2.668), 1.682 (1.421-1.991) and 1.298 (1.039-1.620), respectively]. In multiparae, the length of second stage >1 h was an independent risk factor for episiotomy, blood transfusion, forceps delivery, postpartum hemorrhage and admission to NICU [adjusted OR (95% CI): 8.796 (5.717-13.534), 7.469 (2.874-19.411), 6.135 (3.217-11.699), 2.697 (1.624-4.477) and 1.814 (1.063-3.097), respectively], while the duration of second stage >2 h was the independent risk factor for episiotomy, third- or fourth-degree perineum laceration, blood transfusion, grade Ⅱ postpartum hemorrhage, forceps delivery and postpartum hemorrhage [adjusted OR (95% CI): 38.868 (14.948-101.063), 28.046 (2.780-282.490), 20.076 (5.384-74.866), 16.327 (3.406-78.274), 14.337 (5.351-38.411) and 9.036 (3.880-21.011), respectively]. Conclusions:The duration of the second stage of labor without epidural anesthesia is between that reported by Friedman and by Zhang. A prolonged second stage of labor may increase the risk of adverse pregnancy outcomes.

Objective:To investigate the relationship between body mass index (BMI) and response time of cardioinhibitory type vasovagal syncope (VVS-CI) in children.Methods:The clinical data of 56 children with syncope or pre-syncope were retrospectively analyzed and they visited specialist clinic for syncope and were diagnosed as VVS-CI in the Second Xiangya Hospital, Central South University from December 2012 to September 2019.Based on height and weight, BMI was calculated, and divided into low BMI group (35 cases) and normal BMI group (21 cases). Between the 2 groups, baseline heart rate, head-up tilt test (HUTT) positive response heart rate, baseline head-up tilt test (BHUT) positive response time, and sublingual nitroglycerin-provocated HUTT (SNHUT) positive response time were compared.The correlation between BMI and positive response time was analyzed.SPSS 22.0 software was applied for statistical analysis.Results:There were no significant differences in age, sex, duration of disease and number of syncope between the 2 groups (all P>0.05). No significant differences were found in baseline heart rate and positive response heart rate between the 2 groups [(78.5±15.3) times/min vs.(72.8±8.7) times/min, t=1.223, P=0.230; (44.0±13.9) times/min vs.(47.0±10.0) times/min, t=-0.664, P=0.511]. Compared with normal BMI group, BHUT positive patients/SNHUT positive patients were higher in low BMI group (27/8 cases vs.9/12 cases, χ2=4.839, P=0.027), and the positive response time of BHUT was shorter [(13.1±4.6) min vs.(23.7±9.5) min, t=-2.691, P=0.023]. There were no significant differences in SNHUT positive response time between the 2 groups ( P>0.05). Low BMI was correlated with BHUT positive response time ( r=0.750, P=0.005). Normal BMI was not associated with BHUT positive response time ( r=0.316, P=0.217). There was no correlation between low BMI and normal BMI and SNHUT positive response time ( r=0.177, P=0.431; r=0.021, P=0.940). Conclusions:Low BMI is positively correlated with BHUT positive response time of children with VVS-CI.The time it takes for syncope occurrence was shorter in children with low BMI than that in normal BMI.

Objective:To analyze the association between the types of response to head-up tilt test (HUTT) and levels of various vitamins in children and adolescents with orthostatic intolerance.Methods:Sixty-five cases of children and adolescents 35 males and 30 females aged 5-14 (10.5±2.0) years old who complained orthostatic intolerance symptoms, including syncope, dizziness, headache, and chest tightness, in Children′s Medical Center, the Se-cond Xiangya Hospital, Central South University between November 2018 and April 2019, were enrolled.By comprehensive history, physical examination, and necessary laboratory testing, heart, cerebrovascular and other system diseases were excluded.According to HUTT result, these patients were divided into 2 groups, namely negative HUTT group and positive HUTT group.The serum levels of vitamin A 1, B 1, B 2, B 6, B 9, B 12, C, and E were compared between the 2 groups.Continuous data were analyzed by conducting t-test and categorical data were analyzed by performing χ2 test. Results:(1) There were 32 cases (18 males and 14 females) in negative HUTT group and 33 cases (17 males and 16 females) in positive HUTT groups, with 28 cases of vaso vagal syncope and 5 cases of postural tachycardia syndrome.There were no significant differences in age, gender ratio, and body mass index between the negative HUTT group and positive HUTT group.(2) The serum level of vitamin B 1 of positive HUTT group was lower than that of negative HUTT group [(77.43±16.70) nmol/L vs.(88.56±18.98) nmol/L, t=-2.513, P<0.05], while the levels of vitamin A 1, B 2, B 6, B 9, B 12, C, and E had no significant differences between the two groups (all P>0.05). Conclusions:Patients with positive responses to HUTT relatively lacked vitamin B 1, suggesting the role of vitamin B 1 in the pathophysiological process of neurally mediated syncope.

Objective:To discuss the relationship between heart rate (HR) and heart rate differences (HRD) at different time points in head-up tilt test (HUTT) and the occurrence of postural tachycardia syndrome(POTS) in children and adolescents.Methods:A total of 217 children and adolescents diagnosed as POTS, who complained of syncope or presyncope, were chosen as POTS group (aged 6 to 16 years). During the same period, 73 healthy children and adolescents with matching gender and age were selected as control group.All subjects underwent HUTT from October 2000 to November 2019.Get HR (HR0, HR5, HR10) in baseline, HUTT 5 min and 10 min, HRD (HRD5, HRD10) of HR in HUTT 5 min and 10 min minus HR in baseline.Results:(1) HR5, HR10, HRD5, and HRD10 were higher in the POTS group than those in the control group( P<0.05). (2) Univariate Logistic regression: There was a correlation between HR5, HR10, HRD5, HRD10 and the risk of POTS( P<0.01). (3) Multivariable Logistic regression: For each additional unit of HRD5 and HRD10, the risk of POTS increased by 27% ( OR=1.27, 95% CI1.16 to 1.36) and 28% ( OR=1.28, 95% CI1.20 to 1.38). Conclusion:HR and HRD are related with the occurrence of POTS in children and adolescents, but HR and HRD at different time points of HUTT play the little role on the effect size of the occurrence of POTS.

Objective:To study the diagnostic efficacy and prognostic evaluation value of QT interval dispersion (QTd) in children and adolescents with cardioinhibitory vasovagal syncope (VVS-CI).Methods:From July 2010 to January 2020, 80 children and adolescents who received their first visit or admission to the Pediatric Syncope Clinic of The Second Xiangya Hospital of Central South University and definite diagnosed of VVS-CI due to syncope or presyncope were selected as the VVS-CI group, meanwhile, 80 children and adolescents who had physical examination in the hospital were selected as the control group.QT interval were measured by 12-lead electrocardiogram at the baseline.Results:(1) Comparison between the two groups: Compared with the control group, the VVS-CI group had a significantly lower heart rate ( P<0.05) and significantly longer QT interval, such as the maximum QT interval (QTmax), minimum QT interval (QTmin), QTd, corrected maximum QT interval (QTcmax) and corrected QT interval dispersion (QTcd) ( P<0.05). After follow-up 84 (45, 127) days, compared with the responsive group, the non-responsive group had a significantly longer QT interval, such as QTmax, QTd, QTcmax, corrected minimum QT interval (QTcmin)and QTcd ( P<0.05). (2) Diagnostic efficiency: QTmax, QTmin, QTd, QTcmax and QTcd had a certain diagnostic value in children and adolescents with VVS-CI ( P<0.001). QTd had the largest area under the curve (AUC) (0.914), and had a sensitivity of 86.30% and a specificity of 84.95% at the optimal cut-off value of 28.50 ms for VVS-CI diagnosis.(3) Prognostic evaluation value: QTmax, QTd, QTcmax, QTcmin, QTcd had an estimated value for the prognosis of VVS-CI in children and adolescents ( P<0.05 or 0.01). QTd had the largest AUC (0.906) and the best cut-off value was 34.50 ms, the sensitivity to predict response to VVS-CI intervention was 90.00%, and the specificity was 82.35%. Conclusion:QTd of electrocardiogram has a good estimation value in the diagnosis and prognosis of VVS-CI in children and adolescents.

Objective:To investigate the difference of heart rate variability in cardioinhibitory type vasovagal syncope(VVS-CI) children with different body mass index(BMI).Methods:Clinical data of thirty-four children with syncope or pre-syncope were retrospectively analyzed, who visited specialist clinic for syncope and diagnosed as VVS-CI at the Second Xiangya Hospital of Central South University from January 2012 to December 2019.BMI was calculated based on height and weight, and divided into lean group(BMI≤18.4 kg/m 2, n=19) and normal group(BMI 18.5-23.9 kg/m 2, n=15). Heart rate variability(HRV) of 24 h dynamic electrocardiogram was analyzed using linear analysis method.Time domain index included SDNN, SDANN, rMSSD and pNN50.Frequency domain index included total power(TP), ultra low frequency power(ULF), very low frequency power(VLF), low frequency power(LF), high frequency power(HF) and LF/HF. Results:There was no significant difference in SDNN, SDANN and rMSSD between lean and normal group( P>0.05), but pNN50 increased in lean group( P<0.05). No significant differences were found in TP, ULF, LF, HF and LF/HF between two groups( P>0.05), while VLF was lower in lean group than that in normal group( P<0.05). There was no statistical difference in time domain index and frequency domain index between different gender between lean and normal group( P>0.05). SDNN, SDANN and LF were higher in<12 years old than those in≥12 years old in lean group( P<0.05). There was no statistical difference in rMSSD, pNN50, TP, ULF, VLF, HF and LF/HF( P>0.05). ULF increased and LF decreased in<12 years old compared to ≥12 years old in normal group( P<0.05). No statistical differences were found in SDNN, SDANN, rMSSD, pNN50, TP, VLF, HF and LF/HF( P>0.05). Conclusion:The autonomic nervous regulation function of VVS-CI children with low BMI and normal BMI is different, resulting in HRV difference.There were also differences in HRV between<12 years old and ≥12 years old with the same BMI.

Objective:To compare the quality and diagnostic utility of the three sequences including fast spin echo (FSE), multi-acquisition variable resonance image combination selective (MAVRIC-SL), and isotropic MAVRIC-SL (iso MAVRIC-SL), in evaluating the intervertebral foramen and spinal canal in patients after lateral lumbar interbody fusion (LLIF).Methods:Totally 30 patients after LLIF were enrolled prospectively from May to June 2020 in the Second Hospital of Shanxi Medical University. The patients underwent MRI of the lumbar spine including sagittal MAVRIC-SL and iso MAVRIC-SL sequence three-dimensional volume imaging, and the axial spinal canal level images were reconstructed. FSE sequence sagittal T 1WI and axial T 2WI images were acquired simultaneously. The sagittal and axial images were subjectively graded for visualization of the intervertebral foramen and spinal canal. The artifact area and SNR were measured. The Friedman M test was used to compare the differences in image quality scores, artifact area and SNR among the three sequences. Results:Nonparametric test results showed significant differences in sagittal and axial image quality scores among the three sequences (both P<0.001). Sagittal image quality scores of MAVRIC-SL [4 (4, 4) points] and iso MAVRIC-SL [4 (4, 4) points] were higher than those of FSE T 1WI sequence [3 (3, 3) points, both P<0.001]. The quality scores of MAVRIC-SL and iso MAVRIC-SL showed no significant differences ( P=1.000). The axial image quality score of iso MAVRIC-SL[5 (5, 5) points] were higher than those of MAVRIC-SL [4 (4, 4) points] and FSE T 2WI [3 (3, 3) points, both P<0.05]. The iso MAVRIC-SL images enabled a significantly improved reduction in the artifact area and SNR compared to the MAVRIC-SL and FSE sequence (all P<0.05). Conclusion:The iso MAVRIC-SL acquisitions enhance visualization of the intervertebral foramen and spinal canal and decrease metal artifacts compared with MAVRIC-SL and FSE acquisitions.

Objective To explore the incidence of pain flare (PF) in spine metastasis stereotactic body radiotherapy (SBRT) or hypofractionated radiotherapy (HF) and the prophylactical effect of dexamethasone. Methods Sixty-five patients were treated with spine metastasis SBRT and randomly divided into control group (SBRT or HF, n=32) and treatment group (SBRT or HF and 4.5 mg dexamethasone, n=33). The brief pain inventory (BPI) was used to score the pain before, during and after treatment. PF was recorded and compared between two groups. Results The incidence of PF was 24.6% in all patients (control group: 37.5%, treatment group: 12.1%, P=0.018). PF in both group occurred in d1-2, accounting for 62.5% in all PF (control group: 66.7%, treatment group: 50%, P=0.551). The incidences of PF in control group were 66.7% and 33.3% for three and ten fractions scheme, respectively (P=0.001). However, the incidences of PF in treatment group were 50% and 50% for three and ten fractions scheme, respectively (P=0.643). Conclusion Oral dexamethasone has an excellent efficacy in prevention and treatment of PF in spine metastasis SBRT or HF, with significantly decreased incidence of PF. A phase Ⅲ clinical trial is required to finalize the optimal dose and schedule.

Objective:To explore the relationship between unexplained palpitation in children and head-up tilt test (HUTT).Methods:A total of 142 children with the main symptom of unexplained palpitation were admitted to the Specialist Out-Patient Clinic of Children's Cardiovascular Disease from Sept.2008 to Feb.2017 in the Second Xiangya Hospital,Central South University.Among them,63 cases were male,79 cases were female,with the mean age of (10.12±2.88) years old.The detailed history,physical examinations,conventional 12 electrocardiogram,chest X-ray,echocardiography,myocardial enzymes and thyroid function were all examined.The disorders of heart disease,systemic disease and drug effect were ruled out.The HUTT inspection was then given to them.Results:Among the 142 palpitation cases,79 cases were HUTT positive (55.6％) and 63 cases were HUTT negative (44.4％).The age in HUTT positive patients was older than that in HUTT negative patients (P＜0.05),with no significant difference in gender (P＞0.05).There were three types of hemodynamic changes in HUTT positive patients.Among them,38 cases were postural orthostatic tachycardia syndrome (48.1％),36 cases were the vasovagal syncope vasodepressive type (45.6％) and 5 cases were the vasovagal syncope mixed type (6.3％).There were no hemodynamic types for vasovagal syncope cardioinhibitory type,orthostatic hypotension and orthostatic hypertension.Conclusion:Among the clinically unexplained palpitations children,more than half are caused by unbalanced autonomic nervous function.HUTT can help clear the cause of unexplained palpitations.