Preoperative fractional exhaled nitric oxide is a risk and predictive factor of postoperative cough for early-stage non-small cell lung cancer patients: a longitudinal study.

BACKGROUND

To determine whether preoperative fractional exhaled nitric oxide (FENO) level is a risk and predictive factor of postoperative cough by using the Leicester Cough Questionnaire in Mandarin-Chinese (LCQ-MC).

METHODS

292 early-stage non-small cell lung cancer (NSCLC) patients without preoperative cough were enrolled. 138 patients (47.2%) developed postoperative cough, univariate and multivariate logistic regression analysis were performed to identify the independent risk factors of postoperative cough. For an exploratory analysis, patients with cough were divided into low and high- FENO [≥ 31 parts per billion (ppb)] groups. The LCQ-CM was used to evaluate changes and recovery trajectory of postoperative cough over time between the two groups for 12 months after surgery.

RESULTS

The independent factors of postoperative cough included preoperative FENO level [odds ratio (OR) 1.106, 95% confidence interval (CI): 1.076-1.137, p < 0.001] and duration of anesthesia (OR 1.008, 95% CI: 1.002-1.013, p = 0.004). The low-FENO group reported significantly higher LCQ-MC scores at 1 month after surgery and returned to preoperative physical (28 vs. 91 days), psychological (28 vs. 60 days), social (28 vs. 80 days) and total (28 vs. 91 days) scores faster than the high-FENO group (all p < 0.05).

CONCLUSION

Higher preoperative FENO level and longer duration of anesthesia were independent risk factors related to postoperative cough. Additionally, patients with high preoperative FENO level had worse cough-related quality of life and slower recovery from postoperative cough.

TRIAL REGISTRATION: This study was approved by the Chinese Clinical Trial Registry (Clinicaltrials.gov number: ChiCTR1900023419) on 26 May 2019 and the first patient was enrolled after pre-registration.