The role of positive expiratory pressure (PEP)
in physiotherapy of patients with cystic brosis.
Comparison with oscillatin positive expiratory
Rola podwyższonego ciśnienia wydechowego (PEP)
w zjoterapii chorych na mukowiscydozę. Studium
porównawcze z PEP generującym oscylacje (OPEP)
Teresa Orlik A,E, F
, Anna Wyka-Wojeńska A,D
Rehabilitation Department, Institute of Mother and Child, Warsaw, Poland,
Zakład Usprawniania Leczniczego, Instytut Matki i Dziecka, Warszawa, Polska
Physiotherapy plays a very important role in cystic brosis. Its basic aim is to
regularly clear bronchial passages of mucus which is responsible for exacerbation of
bronchoalveolar symptoms. Positive Expiratory Pressure (PEP) and Oscillating Positive
Expiratory Pressure (OPEP) are among the most commonly used bronchi clearance
methods. It is not entirely clear which technique should be applied in what situations and
whether these techniques are similar to other drainage techniques in terms of eectiveness.
The aim of this study is to review the literature and analyse the eectiveness of both
techniques, to summarise the existing evidence and to point to gaps in the knowledge
about this issue.
PEP, OPEP, physiotherapy, cystic brosis
Fizjoterapia odgrywa bardzo istotną rolę w mukowiscydozie. Jej podstawowym ce-
lem jest systematyczne oczyszczanie oskrzeli z zalegającej wydzieliny odpowiedzial-
nej za rozwój choroby oskrzelowo-płucnej. Do jednych z częściej stosowanych metod
oczyszczania oskrzeli należą technika podwyższonego ciśnienia wydechowego (Positi-
ve Expiratory Pressure – PEP) i oscylacyjnego podwyższonego ciśnienia wydechowe-
go (Oscillatory Positive Expiratory Pressure – OPEP). Nie do końca jest jasne, którą
z technik powinno się stosować i w jakich sytuacjach oraz, czy wymienione techniki są
porównywalne pod względem efektywności z innymi technikami drenażowymi. Celem
niniejszej pracy jest przegląd piśmiennictwa i na tej podstawie analiza skuteczności obu
technik, podsumowanie istniejących dowodów, a także podkreślenie luk w funkcjonują-
cej wiedzy na ten temat.
PEP, OPEP, zjoterapia, mukowiscydoza.
The study was not nanced from any resources.
Badanie nie było nansowane z żadnych źródeł.
Rehabilitation Advances in Rehabilitation/Postępy Rehabilitacji (1), 39 – 45, 2018
A – preparing concepts
koncepcji i założeń)
B – formulating methods
C – conducting research
D – processing results
E – interpretation and
tacja i wnioski)
F – editing the nal
40 Teresa Orlik, Anna Wyka-Wojeńska
Cystic brosis (CF) is an inherited autosomal
recessive genetic disease of white race. It is caused
by mutations of the gene located on the long arm of
chromosome 7, i.e. Cystic Fibrosis Transmembrane
Conductance Regulator (CFTR), which serves as
a chloride channel. The damaged function of CFTR
resulting from the mutation leads to disorders of
the transport of C1 ions through cell membranes of
respiratory epithelium and excessive absorption of
Na+ and water in a cell. This, in turn, leads to lower
hydration and thickness of cilia of the epithelium,
production of thick and sticky mucus and to
disorders of mucociliary clearance, particularly
in the respiratory system . Cystic brosis is
a chronic progressive disease with various clinical
symptoms. Changes in the respiratory system
usually determine the development of the disease as
well as the quality and length of life.
Physiotherapy plays a very important role
in cystic brosis. Its aim is to regularly clear
bronchial passages of thick, sticky mucus which
accumulates in air passages. It was proved that
regular physiotherapeutic procedures, commonly
known as drainage procedures, reduce the number
of exacerbations of bronchoalveolar symptoms,
and, in this manner, help to slow down the disease
progression and to maintain proper lung function
for as long as possible [2,3]. For many years, it has
been highlighted that better prognosis and quality
of life of patients with cystic brosis depend on
the improvement of complex treatment methods,
including more and more ecient physiotherapy
Intensive development of physiotherapy in cystic
brosis was mainly connected with developing
and modifying methods of clearing airways which
would serve as an alternative to postural drainage
(also known as gravity assissted drainage) with
manual chest percussion or vibration. In the 1960s
and 1970s, this type of drainage was a popular
method of clearing bronchi in Europe. Owing to
multidirectional scientic research, traditional
bronchi clearance methods were gradually replaced
with modern, more ecient methods in which
various tools supporting airway clearance were
used. The research which exerted the greatest
inuence on the development of physiotherapy in
cystic brosis mainly regarded negative eects of
gastroesophageal reux on the respiratory system
and the fact that reux was stimulated during
postural drainage [7-9]. Getting to know a key
role of mobilisation of mucus in eective bronchi
clearance and identifying the meaning of autotherapy
for patients’ independence as well as assessing the
eects of this process were also signicant .
The majority of tools, including the ones available
on the Polish market, work in the system of Positive
Expiratory Pressure (PEP) and Oscillating Positive
Expiratory Pressure (OPEP). The application of
PEP improves ventilation in broncholi, reduces the
symptom called “bubble trap” and increases the
Functional Residual Capacity (FRC) [2,11-13]. In
turn, vibrations lead to easier clearance of thick,
sticky mucus from bronchial wall, and expirations
made by the device increase the expiratory ow for
a short time, which makes it easier to push mucus
towards central bronchi [14,15].
Despite the fact that PEP and OPEP have been
in use for over 30 years, it is still not entirely clear
which technique should be used in what situations,
and whether these techniques are similar to other
drainage techniques in terms of eectiveness. The
aim of this study is to review the literature and
analyse the eectiveness of both techniques on
the basis of this review, to summarise the existing
evidence and to point to gaps in the knowledge
about this issue.
Do PEP and OPEP produce measureable
therapeutic eects compared to other drainage
In a cross-over study on 9 patients in a stable
state, Lannefors et al. applied 3 dierent methods
of clearing bronchi . These methods included:
1) postural drainage with thoracic expansion
exercises and Forced Expiration Technique (FET),
2) PEP mask and FET, 3) physical exercise on
a cycloergometer and FET. While assessing the
eectiveness of these techniques on the basis of
the amount of mucus cleared, the authors did not
nd any statistically signicant dierences between
these regimes. A similar study was conducted by
Mortensen et al. . The authors concluded that
postural drainage with FET was as eective as PEP
with FET in tracheobronchial clearance in patients
with cystic brosis.
Advances in Rehabilitation/Postępy Rehabilitacji (1), 39 – 45, 2018 41
In the study by Darbee et al. , two methods were
compared, i.e. PEP and High-Frequency Chest Wall
Oscillation (HFCWO). The eects of both techniques
on arterial blood oxyhemoglobin saturation (SaO2)
and selected spirometric indices were assessed. The
authors revealed that HFCWO and PEP were equally
eective. As far as SaO2 is concerned, the results
were unequivocal. In several patients with respiratory
failure and low values of SaO2, an unacceptable
decrease in SaO2 levels was noted during the therapy
with HFCWO. The authors concluded that the patients
may benet more from PEP during an acute phase of
the pulmonary exacerbation.
McIlwaine et al. carried out research in which
they compared out-patients treated with PEP
technique with those who underwent postural
drainage with chest percussion technique . The
study participants were paired on the basis of similar
values of forced expiratory volume in 1 second
(FEV1%N – up to 15% dierence), gender and age
(up to 3-year dierence). Patients who performed
less than 85% of the recommendations (assessment
based on the questionnaire) were excluded from the
study. Thirty-six patients participated in the whole
study that lasted 1 year. A signicant increase in
forced expiratory volume in 1 second (FEV1) and
forced vital capacity (FVC) was noted in the PEP
group. McIlwaine et al. concluded that PEP is
a better method for maintaining lung function in
patients with cystic brosis compared to postural
drainage with chest percussion.
The majority of studies on the eectiveness of
OPEP were conducted with the use of Flutter VRP1.
Orlik carried out a comparative analysis of the
eectiveness of selected physiotherapeutic methods
in 21 in-patients . She compared 5 airway
clearance techniques, i.e. postural drainage with
chest percussion, postural drainage with percussion
and squeezing, Active Cycle of Breathing Technique
(ACBT), Flutter as well as Flutter with relaxation.
It was revealed that the largest amount of mucus
was removed by coughing in patients undergoing
ACBT and Flutter with relaxation technique. No
statistically signicant dierences were found
between the values of peak expiratory ow (PEF)
and SaO2 measured before and after the application
of any drainage technique.
In their randomised crossover study, Pryor et al.
compared OPEP with Flutter and ACBT . The
authors did not note a signicant improvement
in lung function or oxygenation in the examined
patients. A signicant increase in the amount of
mucus cleared was noted in the study participants
who underwent ACBT. The authors concluded that
there were no signicant dierences between the
application of Flutter and ACBT.
App et al. carried out research that focused on
the eectiveness of autogenic drainage compared
to OPEP with Flutter . The study included
17 patients with cystic brosis. No signicant
dierences were noted between the values of FVC
and FEV1 and the amount of mucus cleared during
the study. However, thickness and stickiness of
mucus were reduced more with the use of Flutter
than during autogenic drainage. The authors
concluded that the vibrations applied with certain
frequency produced by Flutter may reduce the
stickiness of mucus to the bronchial wall.
In the study by Konstan et al. , the mass of
sputum expectorated after the application of Flutter
was compared to the mass of sputum expectorated
in forced cough and during postural drainage with
percussions and vibrations. During the session
with Flutter, all the study participants coughed up
signicantly more mucus (p<0.001) than during
postural drainage and forced cough technique. The
authors concluded that Flutter is more eective
in helping to cough up mucus than traditional
techniques of clearing airways in patients with
In her 7-month study, Orlik assessed the
eectiveness of selected physiotherapeutic methods
in 80 patients divided into 4 subgroups . In each
group, a dierent airway clearance technique was
applied, i.e. postural drainage with chest percussion,
postural drainage with percussion and squeezing,
ACBT and OPEP with Flutter. The author noted
a statistically signicant increase in the values of
all the examined spirometric indices in the ACBT
group. In the OPEP group, an increase in FEV1
(statistically insignicant dierences) and FVC
(statistically signicant dierences) was noted. The
author concluded that forced breathing with Flutter
led to an increase in lung obturation in patients with
42 Teresa Orlik, Anna Wyka-Wojeńska
Comparison of PEP and OPEP
The crossover study by Lagerkvist et al. included
15 patients with cystic brosis . The aim of the
study was to assess the eects of PEP and OPEP
(Flutter) on the values of gas tensions in blood. The
authors concluded that OPEP led to more favourable
changes in the values of PaO2 and PaCO2 compared
to PEP; however, these changes disappeared very
quickly, i.e. within less than 10 minutes. Neither PEP
nor OPEP brought about dierences in spirometric
In their study that lasted 1 year, McIlwain et
al. compared the eectiveness of PEP and OPEP
(Flutter) . Forty patients with cystic brosis
were randomly assigned to one of the assessed
therapies. Patients who performed less than 80% of
the recommended sessions per month (assessed on
the basis of the questionnaire) were excluded from
the study. Thirty-two patients completed the study.
The authors did not reveal statistically signicant
dierences in lung function of patients who were
treated with PEP. In turn, in the case of patients
who were using Flutter, a decrease in the values
of lung function indices was noted after one year,
while FVC dierence was statistically signicant
compared to PEP.
Van Winden et al. conducted a two-week
randomised crossover study in which they compared
OPEP with Flutter method and PEP mask method
applied in clinically stable children with cystic
brosis . The PEF was measured before and
after a morning physiotherapy session and patients
completed a questionnaire regarding day and
night cough, production of sputum and diculty
breathing. No signicant dierences were found
between the PEF in both groups. Moreover, no
dierences were revealed concerning oxygenation
before, during and 30 minutes after the session
of clearing airways. There were no signicant
dierences in the assessment of symptoms included
in the questionnaire for either of the two therapies.
The crossover study by Borka et al. included 10
patients with cystic brosis . Within the study,
260 procedures were performed aimed at measuring
the mass of sputum expectorated. The authors
concluded that PEP was more ecient than Flutter.
Flutter is a useful additional tool.
In the presented publications, the authors obtained
considerably dierent research results. It regarded
both the comparisons of PEP and OPEP with other
drainage techniques and the comparisons of both
methods with each other. The only exception was the
comparison of PEP and OPEP with postural drainage
with percussion which is treated as a conventional
physiotherapy method of clearing bronchi. In 4 of
the presented studies on the eectiveness of the
aforementioned methods, statistically signicant
dierences regarding the values of FEV1, FVC and
mass of sputum expectorated were noted, where PEP
and OPEP produced better outcomes [6,21,24,25].
The application of various research procedures by
dierent authors, e.g. comparing PEP and OPEP with
various therapeutic methods (a dierent method in
every study), and the application of dierent indices
to assess therapy eects bring about unquestionable
diculties in drawing unanimous conclusions on
measurable therapeutic eects of PEP and OPEP in
patients with cystic brosis. The studies also diered
in the length of observation periods, which lasted
from one week to one year. In one work, the number
of performed procedures was given instead of the
length of observation period . The majority of
the examined groups had small populations.
Homogeneity of research groups is a signicant
criterion in the assessment of the eectiveness of
airway clearance techniques that is often neglected
in the research methodology and in the analysis
of results. Due to a progressive character of cystic
brosis, the research should include groups of
patients at similar stages of the disease. Changes in
lungs and bronchi in patients with cystic brosis at
an advanced stage are so big that physiotherapy is
less eective. These patients should not be included
in the same study as patients with less advanced
changes in lungs. For instance, in her study, Orlik
suggested that while assessing the eectiveness
of physiotherapeutic methods, patients with the
diagnosed bronchial hyperresponsiveness should
be analysed separately . An interesting solution
concerning the methodology of assigning patients
to groups was put forward by McIlwaine et al.
Patients were paired on the basis of similar values of
FEV1%N taking into account 15% dierence .
While analysing patients with cystic brosis, it
is important to take into consideration an individual
Advances in Rehabilitation/Postępy Rehabilitacji (1), 39 – 45, 2018 43
reaction of a patient to a particular drainage
technique. An individual reaction depends to
a large extent on motivation and good knowledge
of the drainage technique application. Each of
the techniques can be adapted with regard to
the position in which drainage is performed,
number of cycles, duration of drainage, number
of expirations in a cycle, length of expirations and
length of intervals between cycles. Moreover, high
awareness of parents or adult patients concerning
the role of physiotherapy in treating cystic brosis
is signicant as it allows to control the progress
of a physiotherapeutic session. An interesting
and objective study assessing the cooperation of
a patient while applying the recommended drainage
techniques and performing all the physiotherapeutic
sessions per day was conducted by McIlwaine et
al. They used a questionnaire assessing to what
extent the patients followed the recommendations.
The patients who performed less than 80% of the
recommended sessions per month were excluded
from the study [20,25].
The application of oscillation aimed at making
mucus less thick and sticky, and helping to clear
the airways is a signicant issue in physiotherapy
of patients with cystic brosis. In this context,
the application of OPEP in everyday practice is
perceived as more eective than other airway
clearance techniques and physiotherapeutic
methods. In the aforementioned studies as well
as in other PubMed publications, the authors
obtained extremely dierent results regarding the
eectiveness and role of oscillation in clearing the
airways. Several authors indicated a favourable
inuence of oscillation by Flutter on lung function
in patients with cystic brosis compared to other
techniques of clearing the airways [28,29,30]. Other
authors did not note any inuence of Flutter therapy
on lung function [21,22,23,31]. There was also one
study which revealed that lung function in patients
with cystic brosis worsened after the application
of the therapy with the use of Flutter .
The reviews of Cochrane Database Syst. Rev.
published in 2014, 2015 and 2017 did not provide a
unanimous conclusion regarding higher eectiveness
of PEP and OPEP compared to other physiotherapy
techniques applied in the therapy of patients with
cystic brosis. Only McIlwaine et al. revealed that
in the studies in which the disease advancement was
a basic assessment criterion, a signicant decrease
in the frequency of exacerbations of bronchalveolar
symptoms was noted in patients applying PEP
compared to those using HFCWO (The Vest) .
Moreover, no evidence was found that one device
was better than the other [15, 32,33,].
Performing homogeneous, high-quality research
assessing physiotherapeutic techniques in patients
with cystic brosis is very dicult. Cystic brosis
is a disease with a very changeable clinical
progress with periods of stability and periods of
various-intensity exacerbations of bronchoalveolar
symptoms. Therefore, recruiting study participants
is very hard. Moreover, physiotherapy is a standard
way of treating patients so conducting a blind study
is impossible. This is the reason why short-term
and crossover studies are the dominating types of
studies assessing the eects of physiotherapy on
various indices in patients with cystic brosis. It has
to be highlighted that in the case of cystic brosis,
which is regarded as a rare disease, carrying out
high-quality studies will be often connected with the
fact that the number of participants is insucient to
draw any statistical conclusions.
In the light of the fact that there are many airway
clearance techniques and similar research results
regarding their eectiveness, the question arises
about preferable criteria of selecting a particular
technique for a patient with cystic brosis. More
and more attention is drawn to the fact that factors
other than eectiveness should be taken into account
while selecting a technique. The signicance of
patients’ independence in performing the procedures
and following the rules of physiotherapy as well
as patients’ preferences regarding the applied
techniques are more and more often stressed.
The preferences may be connected with lifestyle,
patients’ beliefs concerning the best eectiveness or
easy application of a given technique, or possibilities
to shorten the duration of a physiotherapy session.
In Poland, there are no current studies which would
assess the preferences of patients or the frequency
of applying particular drainage techniques. Such
multi-centre research was conducted in 2000 and the
results were published in Standardy Medyczne .
The research revealed that Flutter was applied by
44% of the patients over 18 years of age in Poland.
Taking into account my own experience as well as
the diversity and easier availability of devices on
44 Teresa Orlik, Anna Wyka-Wojeńska
the Polish market compared to PEP devices, we
may conclude that currently, the number of Polish
patients using OPEP is higher. The British research
revealed that the frequency of using particular
airway clearing techniques diers signicantly
depending on a country and ranges from 6% to 23%
in the case of OPEP and from 10% to 40% in the
case of PEP .
While selecting a particular drainage device,
a nancial aspect is also very important. The costs
of PEP and OPEP devices are comparable and
range from 200 PLN to 500 PLN, while the Polish
National Health Service refunds 200 PLN once in
two years. Compared to the costs of The Vest, i.e. 32
000 PLN to 36 000 PLN, OPEP is more nancially
attractive for patients with cystic brosis.
OPEP is a method which enables patients to be
independent from their guardians. It takes less time
to achieve similar therapeutic eects than other
methods and is aordable. Despite contradictory
research results, it can be assumed that in the near
future, this method will dominate physiotherapy of
patients with cystic brosis in Poland.
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