Multisite comparison of mucociliary and cough clearance measures using standardized methods

Area of Science:

• Pulmonary Physiology
• Respiratory Medicine
• Biomedical Engineering

Background:

• A standardized protocol was developed and validated across three major research institutions (UNC, JHU, Pitt) to measure mucociliary and cough clearance.
• This initiative aimed to establish a consistent methodology for assessing lung clearance mechanisms.

Purpose of the Study:

• To evaluate the reliability and reproducibility of a novel, standardized protocol for measuring mucociliary clearance (MCC) and cough clearance (CC).
• To identify potential factors, such as study site and gender, influencing MCC and CC measurements.

Main Methods:

• Fifty healthy adults inhaled a radiolabeled aerosol under controlled breathing conditions.
• Lung images were acquired using a gamma camera over 90 minutes, including post-cough measurements.
• Mucociliary and cough clearance were quantified using the area under the retention curve (AUC90), with central/peripheral aerosol distribution (C/P ratio) also assessed.

Main Results:

• Multivariate analysis revealed no significant differences in MCC/CC based on the study site.
• A statistically significant difference was observed in overall MCC/CC between genders, with females demonstrating higher clearance (AUC90=0.84 ± 0.11) compared to males (AUC90=0.90 ± 0.07, p=0.03).
• No significant gender-based differences were found for the C/P ratio or 24-hour residual lung activity.

Conclusions:

• The developed standardized protocol is suitable for multicenter clinical trials evaluating therapies to enhance MCC and CC.
• Findings suggest potential sex-based differences in lung clearance that warrant further investigation.