Objective:To localize the impacted maxillary canine and to observe the root resorption of adjacent incisor in 3 dimen-sions using cone beam computed tomography(CBCT).Methods:92 impacted maxillary canines in 63 patients were scanned by CBCT.The three-dimensional images were obtained by multiplanar reconstructions(MPR).The cusp tip of each impacted canine was localized and set to the X,Y and Z planes after the observation of sagittal,coronal and axial views.The root resorption of adjacent in-cisors was observed.Results:In the X-axis,92% of impactions were mesial by 1 0.4 to 1 5.1 mm,8% distal by 2 to 5 mm;in the Z-axis,60% of impactions were palatal by 1 to 4 mm,40% buccal by 0 to 4 mm.41 .3% of the impacted canines were without root resorption of adjacent incisor,36.5% with slight,1 4.3% with moderate and 7.9% with severe root resorption of the adjacent inci-sor.Conclusion:The most frequent location of impacted maxillary canine is palatal and mesial with high incidence of root resorption of adjacent incisor.

Objective To assess the clinical features and treatment of children with long QT syndrome (LQTS)and syncope.Methods Eleven cases of children with LQTS and syncope between January 2009 and July 2014 in Hunan Children′s Hospital were retrospectively analyzed for clinical features,treatment and long term follow -up.Results There were 11 cases of children with LQTS aged 4.0 -14.5(9.16 ±2.71)years,8 male and 3 female, with syncope more than once.The range of QTc was 460 -521(483.72 ±22.90)ms.For 3 cases of acquired LQTS,1 case was parathyroid hypothyroidism causing hypocalcemia,1 case was myocarditis complicated with third degree atrio-ventricular block,and 1 case showed atrial flutter receiving amiodarone post congenital cardiac surgery.All patients re-covered after the inducement removed and primary illness cured.For 8 cases of congenital LQTS,3 cases of LQTS un-derwent genetic test (1 case of KCNQ1 gene mutation,2 cases of KCNH2 gene mutation).One case died after frequent torsade de pointes (Tdp)and ventricular fibrillation during hospitalization,the remaining 7 patients were given oral pro-pranolol,potassium chloride sustained -release tablets after discharge.Follow -up time was 8 to 75 months,an average of (45.73 ±24.42)months.One case died suddenly at home after 25 months of follow -up.The remaining 6 cases of children with congenital LQTS could withstand general activities without syncope,in which 4 cases had normal QTc by electrocardiography(ECG),and the findings in 2 cases did not change compared with those previously.The QTc re-turned to normal in children with acquired LQTS in the follow -up review.Conclusions Children with congenital LQTS should receive early genetic screening and genotyping for rational use of drugs.For children with higher risk of sudden death,drug therapy combined with implantable cardioverter defibrillator should be considered.For acquired LQTS,it should be better to remove the inducement and treat primary disease actively.

Objective:To analyze and discuss the application value and teaching effect of simulate patients (SP)-assisted problem-based learning (PBL) combined with team-based learning (TBL) mode in pediatric first aid teaching, in order to provide a new reference for the reform of standardized residency training and teaching mode of pediatrics in the new era in China.Methods:A total of 103 residents who participated in the standardized training in the Department of Pediatrics of Hunan Children's Hospital from January 2018 to December 2020 were selected as the research objects, and they were divided into the control group (50 cases) and the experimental group (53 cases). The control group adopted the previous teaching mode of residents, while the experimental group adopted the SP-assisted PBL combined with TBL mode. In this study, SPSS 22.0 software was used for t test and chi-square test. Results:The examination scores of the experimental group in the theoretical knowledge of pediatric first aid, clinical thinking and skills, and application of pediatric first aid skills were higher than those in the control group [(86.98±3.42), (85.69±5.13), (89.62±4.75)] vs. [(77.23±4.16), (81.16±3.96), (76.54±5.78)], with statistically significant differences between the two groups ( P<0.05). The questionnaire survey showed that the clinical thinking and pediatric emergency skills, doctor-patient communication ability, teamwork ability and other aspects of the experimental group were significantly better than those of the control group ( P<0.05). Conclusion:The SP-assisted PBL combined with TBL mode can produce positive effects in the standardized residency training of pediatrics, which will help residents better master pediatric first aid skills, improve their clinical comprehensive capabilities, and be more conducive to improving the quality of pediatric residency training, which is worth promoting in the new era.

Objective:To retrospectively analyze the clinical application of extracorporeal membrane oxygenation (ECMO) in severe adenovirus pneumonia, and to evaluate the application value of ECMO in children with severe adenovirus pneumonia.Methods:Children diagnosed with severe adenovirus pneumonia and intervened with ECMO in the Hunan Children′s Hospital from January 1, 2018 to December 31, 2019 were recruited in this study for analyzing.The gender, age, clinical manifestations, mechanical ventilation duration, ECMO duration, the length of hospital stay, complications and prognosis were collected and analyzed.Results:A total of 4 children were included in the study, involving 2 cases were successfully evacuated from ECMO.Finally, 3 children died, and 1 case survived.Three death cases had a longer than 18 days of duration from the onset to the start with ECMO.Their ventilator assist time before star-ting ECMO was 3-5 days, and ECMO intervention time was longer, with the maximum of 27.5 days.The survived case had an 11-day duration from the onset to the start with ECMO, and the ventilator assisted time and ECMO intervention time were 5 days, and less than 10 days, respectively.Conclusions:ECMO treatment for children with severe adenovirus pneumonia has a low success rate, but it is still the most important way to save children.Early application of ECMO can improve the prognosis of children with severe adenovirus pneumonia.

Objective:To summary the mixed infection as well as clinical characteristics and analyze the risk factors for mixed infection of severe adenovirus pneumonia(SAP) in children.Methods:The clinical data of 114 children with SAP were retrospectively analyzed.Multivariate Logistic regression analysis was performed to assess the risk factors for mixed infection.Results:The incidence age was from 6 months to 2 years(62.5%). High fever(94.7%), cough(98.2%), dyspnea(86.8%) and lethargy(95.6%) were the main symptoms.Laboratory examination showed that children with SAP were prone to increased white blood cell count, C-reactive protein, procalcitonin, aspartate aminotransferase, alanine aminotransferase and CK-MB, as well as decreased proportion of CD3 + , CD4 + , CD8 + , CD4 + /CD8 + and NK cells.The main complications intrapulmonary organ were respiratory failure(80.7%). The main complications extrapulmonary organ were circulatory complications (55.3%). SAP was easily combined with other pathogenic infections.Streptococcus pneumoniae(22.9%)was the most common bacterial pathogen.Respiratory syncytial virus(10.0%)were the most common virus, in addition, mycoplasma pneumoniae(17.1%) was also common.Multivariable Logistic regression analysis showed that the decreasing ratio of CD4 + /CD8 + and NK cells, congenital heart disease and congenital airway dysplasia were the independent risk factors for mixed infection of SAP in children( P<0.05). Conclusion:The SAP patients could easily suffer from mixed infection and high fatality rate.Immune dysregulation is the important risk factors for mixed infection of SAP in children.So immunoregulatory treatment is very important.