Abstract:Objective To investigate the relationship between concentration of preoperative fractional exhaled nitric oxide (FeNO) and postoperative pulmonary complications (PPCs) in elderly patients undergoing thoracic surgery. Methods Ninety-two elderly patients who underwent thoracic surgery in our hospital were selected as the study objects from June 2017 to June 2019. According to whether PPCs occurred, they were divided into PPCs group (n = 16) and non PPCs group (n = 76). Baseline data and operation related indexes of the two groups were compared. FeNO value of the two groups was measured 10 minutes before operation by naculon breath analyzer. Results The age of PPCs group was higher than that of non PPCs group (P < 0.05); the proportion of patients with smoking history and COPD history was higher than that of non PPCs group (P < 0.05); the proportion of patients with endoscopic surgery was lower than that of non PPCs group, the difference between the groups was statistically significant (P < 0.05). The difference of FeNO distribution between PPCs and non PPCs was statistically significant (P < 0.05).Age, smoking history, COPD history, endoscopic surgery or not and FeNO value in 10 minutes before operation were included in binary logistic regression analysis. The results showed that endoscopic surgery [Ol ^ R=12.18 (95% CI: 1.28, 116.33)], age [Ol ^ R=0.88 (95% CI: 0.81, 0.96)], COPD history [Ol ^ R=758.20 (95% CI: 11.04, 52086.77)] and FeNO value in 10 minutes before operation [Ol ^ R=1.34 (95% CI: 1.13, 1.59)] were the influencing factors of PPCs in elderly patients with thoracic surgery. ROC curve was drawn according to the FeNO value 10 minutes before operation. The area under curve (AUC) was 0.821, and the cut-off value of FeNO was 27.5 ppb. At this time, the Jordan index was 0.583, the sensitivity was 68.8%, and the specificity was 89.5%. Conclusion The high FeNO value 10 minutes before operation was related to the increased risk of PPCs in elderly patients undergoing thoracic surgery.