The clinical investigation of clara cell protein 16 for the early diagnosis of acute respiratory distress syndrome

Objective To explore the clinical value of clara cell protein 16 (Cc 16) in the early diagnosis of ARDS in critically ill patients.Methods A total of 55 critically ill patients admitted between March 2013 and December 2013 in the Intensive Care Unit were enrolled for study.The inclusion criteria were as follows:sepsis,pneumonia,multiple injuries,patients after emergency or elective operation and non-cardiogenic diseases,whereas the exclusion criteria were cardiogenic pulmonary edema,age ≤ 18 years or≥80 years and disease course prolonged over one week.The level of serum Cc16 was detected with enzyme linked immunosorbent assay (ELISA).In addition,data of other biochemical examinations,the Acute Physiology and Chronic Health Evaluation (APACHE]Ⅱ) score and the relevant medical data were documented.The patients were divided into ARDS groups and non-ARDS groups based on clinical data met Berlin definition.Results The sensitivity and specificity of serum Cc16 for diagnosis of ARDS were 92％ and 80％,respectively with the area under the curve being 0.92,which were better than those of APACHE Ⅱ score,D-dimer,C-reactive protein,N-terminal pro-brain natriuretic peptide and serum albumin detected by the means of receiver operating characteristic curve,and cut off value was 20.62 ng/L.The bivariate analysis showed there was negative correlation between Cc16 and oxagenation index in ARDS patients and the Pearson correlation coefficient of serum Cc16 with oxygenation index was r =-0.342 (P =0.04).The results of one-way analysis of variance showed difference in level of Cc16 between subgroups (F =15.76,P =0.005 17).The level of Ccl6 in severe ARDS group was (64.18 ± 12.95) ng/L which was higher than that in mild ARDS group (35.87 ± 11.28) ng/L (P =0.001 14),and in moderate ARDS group (38.66 ± 20.14) ng/L (P =0.004 9),and in non-ARDS group (16.72 ± 8.74) ng/L (P =0.000 32).There was no statistically significant difference in Cc16 level between mild ARDS group and moderate ARDS group (P =0.682).The level of serum Ccl6 did not correlate with type or days of respiratory ventilation support,28-day survival rate or 120-hour survival rate and days of ICU stay and hospital stay.Conclusions The diagnostic value of serum Cc16 is very high in determining the presence and severity of ARDS in addition to the Berlin criteria in critically ill patients accurately assessing degree of lung injury. Key words: Clara cell protein 16;  Acute respiratory distress syndrome;  Early diagnosis; Critically ill patients;  Receiver operating characteristic curve