Airway clearance techniques - a proposed classification based on definitions?

Airway clearance techniques (ACT) are a longstanding modality of treatment in many chronic respiratory diseases. Their aims are to counteract airway obstruction by mobilizing airway secretions and/or by limiting the airway collapse.

This review first outlines the physiological mechanisms underlying ACT. In a second part, it categorizes the ACT into seven distinct groups. These groups include both instrumental and non-instrumental ACT. Strategies such as physical activity and upper airway clearance techniques are also considered as ACT due to their complementary roles in mobilizing airway secretions.

The lack of standardized definitions for airway clearance techniques (ACT) leads to significant differences in the clinical practice and effects because the variability in physiological mechanisms. Studies show that both manual and instrumental ACT are influenced by therapist-dependent factors such as applied force, duration of the application, and patient positioning. To ensure reproducibility and effective teaching, a single, physiologically grounded description of ACT is urgently needed.