Positive expiratory pressure techniques in respiratory patients: old evidence and new insights.

Educational aims
To describe the rationale for the use of positive expiratory pressure (PEP) techniques as a means of chest physiotherapy in respiratory patients.

To compare both the effectiveness and problems of the most popular PEP devices in clinical practice.

To introduce the impact and potential interest of temporary PEP (TPEP) techniques in this field.

Summary
In recent years, a large number of PEP devices, used to assist in airway clearance or, at the very least, to allow for effective self-administered physiotherapy, have been developed. A secondary clinically relevant objective of these devices is to prevent recurring infections and atelectasis, or to improve pulmonary mechanics and facilitate gas exchange, thus lowering the impact of disease progression. The use of PEP devices in this field has become widely accepted for two main reasons: 1) their clinical efficacy, which is as great as that of conventional chest physiotherapy practice, and 2) the high level of acceptance and compliance by patients, which makes PEP devices very useful in the domiciliary environment. The functional and clinical response of any specific PEP device, with or without vibration effect, may vary according to a specific diagnostic group. Ultimately, the choice of airway clearance strategy may be the one that is clinically effective, cost-effective and preferred by the patient and which, therefore, supports adherence. Recent technology has enabled the development of a new machine, which is able to apply a TPEP at a level several times lower than that applied with previous devices; thus, at least potentially, it is able to reduce the risk of mechanical stress injury to the bronchial tree and lung parenchyma. In this review, we will discuss the rationale for the use of PEP devices and compare both their effectiveness and problems in clinical practice. Finally, we will introduce the application and potential interest of TPEP as a new means for treating patients with hypersecretion.