Airway clearance: physiology, pharmacology, techniques, and practice.

Clinicians and their patients are troubled by respiratory secretions, and standard practice calls for efforts to clear secretions from the lungs. On one hand, mucus production and cough are important for airway defense and protection of the lower respiratory tract against inhaled irritations. On the other hand, excessive mucus obstructs airways and excessive cough has been associated with a number of complications. The objective of this conference was to review the scientific basis and clinical evidence for the use of airway clearance therapy to guide the most appropriate approach to airway clearance. An international group of clinicians and scientists addressed the physiology of mucus production and cough, pharmacologic approaches to airway clearance, and the variety of techniques available for airway clearance. Specific issues related to airway clearance in critically ill patients, children, and the elderly were discussed. Outcome measures related to evaluating mucus clearance therapy were also presented. One of the themes repeated consistently throughout this conference was the dearth of high-level evidence related to airway clearance techniques. Appropriately powered and methodologically sound research is desperately needed in this area.