Disease 2019 (COVID-19) as a pandemic. As of 22 April, more than 2.4 million cases have been confirmed worldwide 1 . In light of the widely documented lung injuries related with COVID-19 2-3 , concerns are raised regarding the assessment of the lung injury for discharged patients. A recent report portrayed that discharged patients with COVID-19 pneumonia are still having residual abnormalities in chest CT scans, with ground-glass opacity as the most common pattern 4 . Persistent impairment of pulmonary function and exercise capacity have been known to last for months or even years [5][6][7][8] in the recovered survivors with other coronavirus pneumonia (severe acute respiratory syndrome/SARS and middle east respiratory syndrome/MERS). However, until now, there is no report in regard to pulmonary function in discharged COVID-19 survivors. Our manuscript aims to describe the characteristics of pulmonary function in these subjects.We recruited laboratory confirmed non-critical COVID-19 cases, from February 5th to March 17th from admitted patients. According to the WHO interim guidance 9 and the guidance from china 10 , disease severity were categorized as mild illness(mild symptoms without radiographic appearance of pneumonia), pneumonia(having symptoms and the radiographic evidence of pneumonia, with no requirement for supplemental oxygen), severe pneumonia(having pneumonia, including one of the following: respiratory rate > 30 breaths/minute; severe respiratory distress; or SpO2 ≤ 93% on room air at rest), and critical cases (e.g. respiratory failure requiring mechanical ventilation, Septic shock, other organ failure occurrence or admission into the ICU). Critical cases were excluded from our study.Spirometry and pulmonary diffusion capacity test (Cosmed PFT Quark, Rome, Italy) were performed following the ATS-ERS guidelines on the day of or one day before discharge. To minimize cross infections, carbon monoxide diffusion capacity (DLCO) was measured by the single-breath method. Written informed consent was obtained from all patients, and the study was approved by the ethics committee of The Guangzhou Eighth People's Hospital.One-hundred and ten discharged cases were recruited, which included 24 cases of mild illness, 67 cases of pneumonia and 19 cases of severe pneumonia (Table 1). The mean age of these cases was 49.1 years and fifty-five of them were females. Forty-four (40%) patients had at least one underlying comorbidity, of which 23.6% had hypertension and 8.2% had diabetes. Only 3 patients (2.7%) were reported having chronic respiratory diseases (one patient with asthma, one with chronic bronchitis and one with bronchiectasis). No significant differences were found among the three groups of cases, in the relation to gender, smoking status, underlying disease and the BMI value. The duration from onset of disease to pulmonary function test was 20±6 days in cases with mild illness, 29±8 days in cases with pneumonia and 34±7 days in cases that presented severe pneumonia. On the day of discharge, the SpO2% on ro...

Chinese measured spirometry data. The present study also compared with other published Chinese equations for spirometry. Results: A total of 7,115 eligible individuals aged 4 to 80 years (50.9% females) were recruited. Reference equations against age and height by gender were established, including predicted values and lower limits of normal (LLNs). Validated with Chinese data, the mean percentage differences of Caucasian reference values adjusted with ethnic conversion factors were −10.2% to 1.8%, and the percentages of total subjects under LLNs were 0.1% to 8.9%. Compared with this study, the percentage differences of previous Chinese studies ranged from −17.8% to 11.4%, which were found to significantly overestimate or underestimate lung IntroductionSpirometry has been widely used for diagnosing respiratory diseases, quantifying disease severity, and assessing disease prognosis (1,2). Accurate interpretation of spirometry requires appropriate reference values derived from its own ancestry population (3), including lower limits of normal (LLNs), which could be helpful for assessment of abnormal pulmonary function in patients with pulmonary diseases.There are over 40 million overseas Chinese (4) and 1.3 billion mainland Chinese (5) in the world (about 22% of the global population), indicating the huge medical demand (6). Embarrassingly, standardized nationwide spirometric reference values for Chinese were unavailable.In 2012, Global Lung Function Initiative (3) recommended multi-ethnic reference values for African-Americans, Southeast Asians (SEA-GLI2012) and Northeast Asians (NEA-GLI2012), which were largely established with Caucasian data and adjusted with fixed ethnic conversion factors in the whole age range. In addition, other Caucasian reference values adjusted with fixed ethnic conversion factors were also applied in China (7,8), such as European Committee of Steel and Coal equations adjusted for Chinese with the suggestion of Zheng et al. (Chinese-ECSC1993) (9,10), and the third national health and nutrition examination surveys equations adjusted with 0.88 times for Asian-American (Asian-NHANESIII 0.88) (11,12). Given the dynamic changes of gene, economic, environment, nutrition and et al., it remains unknown whether those fixed ethnic conversion factors reliably reflect the difference of spirometry between Caucasians and Chinese.Although several spirometric reference values for Chinese have been published (13-22), the major disadvantages in these studies limited the nationwide use, including small samples, limited age ranges, small local regions, as well as different study protocols and quality control. Without LLNs for nationwide Chinese, a fixed 0.7 of forced expiratory volume in 1 second to forced vital capacity (FEV 1 /FVC) instead of LLNs was frequently applied for the diagnosis of "airflow limitation" in previous studies (7,23,24), leading possible underdiagnosis in younger subjects and over diagnosis in elderly. Moreover, In the nationwide questionnaire surveys on clinical application of pulmon...

CNs partially improve the extent and accuracy of neck dissection and preserve the normal anatomic structure and physiologic function of the parathyroid glands during thyroid cancer surgery.