CJCP     2022 24 (9):  1020-1026    ISSN: 1008-8830  CN: 43-1301/R Value of fractional exhaled nitric oxide combined with impulse oscillometry in the diagnosis of asthma in preschool children GUAN Zhi-Yuan, FENG Yong, HAN Xiao-Hua Department of Pediatric Respiratory Medicine, Shengjing Hospital of China Medical University, Shenyang 110004, China (Han X-H, Email: hanxh5519@163.com) Received: 2022-04-08  Revised: null  Online: null Supporting info