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Respir Med. 2015 Mar;109(3):297-307. doi: 10.1016/j.rmed.2014.11.003. Epub 2014 Nov 12.

Positive expiratory pressure - Common clinical applications and physiological effects.

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Department of Physical Therapy and Occupational Therapy, Sahlgrenska University Hospital, Sweden; Department of Physical Therapy, Sahlgrenska Academy at Gothenburg University, Gothenburg, Sweden; Department of Gastrosurgical Research & Education, Sahlgrenska Academy at Gothenburg University, Gothenburg, Sweden. Electronic address:
Cystic Fibrosis Centre, Rigshospitalet, Copenhagen University Hospital, Copenhagen, Denmark.
Department of Medical Sciences, Clinical Physiology, Uppsala University, Uppsala, Sweden; School of Health and Medical Sciences, Örebro University, Sweden.


Breathing out against resistance, in order to achieve positive expiratory pressure (PEP), is applied by many patient groups. Pursed lips breathing and a variety of devices can be used to create the resistance giving the increased expiratory pressure. Effects on pulmonary outcomes have been discussed in several publications, but the expected underlying physiology of the effect is seldom discussed. The aim of this article is to describe the purpose, performance, clinical application and underlying physiology of PEP when it is used to increase lung volumes, decrease hyperinflation or improve airway clearance. In clinical practice, the instruction how to use an expiratory resistance is of major importance since it varies. Different breathing patterns during PEP increase or reduce expiratory flow, result in movement of EPP centrally or peripherally and can increase or decrease lung volume. It is therefore necessary to give the right instructions to obtain the desired effects. As the different PEP techniques are being used by diverse patient groups it is not possible to give standard instructions. Based on the information given in this article the instructions have to be adjusted to give the optimal effect. There is no consensus regarding optimal treatment frequency and number of cycles included in each treatment session and must also be individualized. In future research, more precise descriptions are needed about physiological aims and specific instructions of how the treatments have been performed to assure as good treatment quality as possible and to be able to evaluate and compare treatment effects.


Breathing exercises; Physiology; Positive expiratory pressure

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