Chronic Refractory Cough: Objective Improvement With Aerodynamic-Focused

Abstract

Objective: Previous investigations have reported that a chronic cough that is refractory to medical therapies improves with behavioral therapies. However, the treatment parameters that may account for improvement in cough symptoms have not yet been objectively documented. The purpose of this study was to document changes in chronic refractory cough using a breath training protocol. Methods: The charts of 27 patients with a long-term chronic cough (>6 months) refractory to various medical treatments were reviewed. These patients received 2–4 sessions of breath training therapy over a 6-month period. Treatment sessions consisted of breathing modification exercises such as those reported in the literature. Aerodynamic parameters including mean estimated subglottal air pressure, mean airflow rate, laryngeal airway resistance, and maximum phonation time were obtained before treatment and 6 months after therapy. Patients also completed the Cough Severity Index at the first visit and 6 months after treatment. Results: Twenty four of the 27 patients (M:F = 6:21), with a mean age of 62.4 (range = 28–78, median = 66) had significant Cough Severity Index improvement from 16.74 to 10.04 (P< 0.001) after therapy. Maximum phonation time increased significantly from 12.00 to 16.38 seconds (P= 0.006); mean estimated subglottic air pressure decreased significantly from 7.58 to 6.36 cm H2O (P= 0.004); laryngeal airway resistance decreased significantly from 52.97 to 40.64 ppm (P= 0.013). Conclusion: This investigation provides evidence that patients who followed a protocol that focused on a breath training program reduced their chronic cough. Significant relationships between patient self-assessment of chronic cough and aerodynamic measures of subglottic pressure and glottal airway resistance were found in this group.