LHASA, May 8 -- Many children in southwest China's Tibet suffer from congenital heart diseases (CHDs) due to high altitude and a lack of oxygen. Given the limited local medical conditions, medical teams from Jiangsu Province in east China traveled to Lhasa to screen children under the age of 18 and review patients who had previously received surgery. Over 10,000 children were examined by medical professionals in a single week. On May 8, 60 of those children were screened out and flown to Jiangsu for free surgery.