Application and advantages of induced sputum cytology with gradient concentrations of hypertonic saline in the diagnosis of chronic cough

Abstract

Objective: To explore the application and advantages of induced sputum cytology with gradient concentrations of hypertonic saline in the diagnosis of chronic cough (CC).

Methodology: This was a prospective study. A total of 180 patients with CC admitted to Baoding No.1 Central Hospital between January 2022 to November 2024 were selected, and 115 individuals undergoing physical examinations during the same period were selected as the control group. Induced sputum cytology with gradient concentrations of hypertonic saline was conducted for all subjects. Analyzed the success rate of sputum induction and compared the results of sputum cytology examination of patients with different etiologies and the diagnosis rate of each test item for different etiologies.

Results: The success rate of sputum induction was 92.78%(167/180), and the incidence of adverse reactions during the induction was 9.44%(17/180) in the patients with CC. These adverse reactions were resolved spontaneously after the induction was terminated. In patients with successful sputum induction, etiology was definitely diagnosed in 93.41%(156/176) patients, including cough variant asthma (CVA) in 38/156 patients (24.36%), eosinophilic bronchitis (EB) in 14/156 patients (8.97%), upper airway cough syndrome (UACS) in 25/156 patients (16.03%), gastroesophageal reflux cough (GERC) in 16/156 patients (10.26%), and atopic cough (AC) in 63/156 patients (40.38%). The etiology was unknown in 11/167 patients (6.59%).

Conclusion: The success rate of sputum induction is high and the etiology is comprehensively diagnosed in patients with CC when induced sputum cytology with gradient concentrations of hypertonic saline is used.