Undiagnosed Congenital Heart Disease in Children in Rural Yunnan, China

The aims of this dissertation were to investigate the distribution of congenital heart disease (CHD) and its catastrophic outcome -- Eisenmenger syndrome in children in Yunnan Province, China, and to discuss the optimal method to implement newborn CHD screening in rural Yunnan. CHD is one of the most common birth defects that occurs in around 8 per 1000 live births. Repairing a heart defect early in life can prevent the development of its inoperable outcome -- Eisenmenger syndrome. In the first part of this dissertation, I reported my retrospective medical record review of 1301 children in rural Yunnan who were diagnosed with a CHD between 2006 and 2016. I used the methods of descriptive analysis and logistic regression to analyze data and concluded that ventricular septal defect, atrial septal defect, and patent ductus arteriosus were the three most common CHDs. Two in every 100 pediatric cardiac patients had developed Eisenmenger syndrome, and age is the most important risk factor for developing Eisenmenger syndrome in children with CHD.The second part of this dissertation is a report of a program to train Yunnan Province obstetric doctors and nurses regarding proper exam of the hearts of newborn babies. Newborn CHD screening, including pulse oximetry screening and heart auscultation, can identify critical and major CHDs early in life with very high sensitivity and specificity. In rural Yunnan, newborn CHD screening was not previously practiced. We, therefore, designed an on-site, one-day training program to educate Yunnan obstetric and pediatric staff on proper CHD screening. The training program, which started in July 2015 and lasted through 2016, trained 2,175 medical staff. I used pre- and post- training questionnaires and behavior checklists to evaluate the training. Evaluation results showed that after training, trainees demonstrated improved knowledge and practice of CHD screening. Since most of residents in Yunnan live at mild and moderate altitudes (between 500 and 2500 meters), and high altitude affects pulse oximetry screening results, the cut off values of pulse oximetry screening should be adjusted in most of Yunnan. In the third part of my dissertation, I investigated the relationship between pulse oximetry screening result (blood oxygen saturation) and altitude in 41,097 newborn babies. Study results showed that every 1,000-meter increase in altitude was associated with a 1.54 percent decrease in mean SpO2. I recommended new cut-off values of pulse oximetry screening at mild and moderate altitudes. In conclusion, a great number of pediatric CHD patients in rural Yunnan did not receive timely diagnosis or treatment early in life. Newborn CHD screening was an effective method to prevent late diagnosis of CHD, and due to our efforts, this kind of screening has been routinely implemented in rural Yunnan, China