An integrative review on the positive expiratory pressure (PEP)-bottle therapy for patients with pulmonary diseases.

PEP-bottle therapy has been proved to improve lung volume, to reduce hyperinflation, and to remove secretions. The device delivers a pressure equal to the water column only if the inner diameter of the tubing and the width of the air escape orifice are equal or greater than 8 mm, and the length of tubing ranges between 20 and 80 cm. The cost of a PEP-bottle device is significantly lower if compared with other commercially available devices having the same therapeutic purposes.