The [Positive Expiratory Pressure] PEP Bottle

The following document is intended to provide guidelines to PHYSIOTHERAPISTS and RELEVANT HEALTH PRACTITIONERS only on the subject matter, it is NOT intended to serve as a PUBLIC DIY GUIDELINE.
The document outlines details on how to make a PEP bottle, how to use it, along with recommendations / precautions and contraindications. Therefore, the device is for treatment purposes administered by a physiotherapist. Any action that general public take upon the information in this document is at their own risk and potentially harmful. Information outlined here has been adapted from various resources and consultations. It is therefore still best practice to verify the information below and is not a substitute for evidence-based research. We merely aim to make this information easily available to practitioners during the current spike in COVID-19 infection rates.


The system utilized hereunder is a Semi-Closed System, and not the conventional open system, this is to reduce droplet spread of COVID-19. Hence the water level has been adjusted in order to achieve the required PEEP. Please take note of all sterilization and other recommendations, precautions and contraindications that follow.
1) 1x 2 litre milk bottle. A 2ltr cool drink bottle may not be used. The “squared” base of the 2ltr milk bottle (or the likes) is crucial.
2) Pipe / tube. 50cm length, with an inner diameter equal to or greater than 8mm. Make an incision at the end of the pipe that would be inside the bottle at the bottom. The shape would then resemble that of the tip of an elephant’s trunk. This is to prevent the pipe from sitting flush at the bottom of the bottle.
3) Drill a hole through the lid, allowing a 2mm play between the pipe and the lid once inserted. (eg. Below, 1mm on either side)

1) Previously 15cm height of water was used to achieve 15 PEEP (unit of measure being cmH2O) in an open system (without lid), however with the semi-closed system the water is less in order to achieve approximately the same PEEP. We will therefore use 1150ml of water in this semi-closed system, and not 15cm height of water as is commonly used in open systems. (see recommendations below on how individualize the amount of water to the specific patient, much like how exercise is graded).


1) Ensure that the pipe remains in a vertical (full upright) position throughout the entire duration of treatment. It should not be bent in any direction.
2) With the pipe away from the mouth, the patient should take a slow deep
(diaphragmatic) breathe in nasally, then exhale into the pipe slowly over 7 seconds.
3) Patient should be in a seated position, with good posture, preferably not making any contact with the back rest of the chair. If this is not possible, semi-fowlers position would then be optimal.
4) Do 5-6 breaths every 30 min, or hourly (while awake). Gradually increase to 10 breaths if tolerated. Decrease to 3 breaths and work up if patient is struggling (see recommendations below on how individualize the amount of water to the specific patient to aid this process).
5) It is expected for the patient to experience dizziness, if this happens, stop, breathe comfortably, and continue once the dizziness passes.
6) After completion of the session, continue with ACBT AFTER 5 MINUTES of rest.
Note: if the cap of the bottle is closed and the pipe passes flush through (without play), then the pressure in the bottle remains at the level of the water column e.g. 5cmH2O (during the whole expiration cycle) and DOES NOT return to atmospheric pressure at the end of expiration as it would if the top of the bottle was left open. Therefore, your PEP bottle with sealed closed lids may act more like a CPAP and not like oscillating PEP where pressure returns to atmospheric pressure at the end of expiration. Hence the importance of the 2mm play between the lid and the pipe.

The physiotherapist will be required to bring an already-assembled PEP bottle (2l milk bottle) to the patient’s house. The bottle, lid and pipe should be cleaned thoroughly by immersing and filling the bottle for half an hour with warm (not boiling) soapy water. Rinse it a few times afterwards. Some bottles would need a second wash. It is important to note that boiling water is not to be used for the cleaning as the heat would most probably degrade the plastic. One may also use 70% alcohol, or 72hours and more of direct sunlight, or diluted bleach (ratios readily available on the internet). Where possible it is recommended for the patient to assemble his/her own bottle at home with your tutorship, to mitigate spread of infection.

The reasoning behind the use of a milk bottle is that these are widely available and cost effective to use in our community project, in order to help as many people as possible. However, it is not a high-quality plastic and therefore only to be used for that crucial 4-5 days of treatment. After this period, these bottles should be discarded and a new 2ltr milk bottle will be provided. These bottles can only be used by one person and not shared with another family member or person. It is also not a toy; it should be kept out of reach of children. The bottle should be clearly labelled PEP to prevent unintended use and to prevent patients from drinking the water erroneously. The bottle and pipe must be disinfected on the outside as well before handing over. The physiotherapist must ensure that the patient knows how to wipe it before and after use on the outside surface, it should be left to dry completely (after washed with warm soapy water) before using it for the next treatment session. Also teach the patient to wipe the
surrounding surfaces after use due to droplet spread. Remember that usage of this device increases the likelihood of eliciting a cough, hence cleaning and droplet spread precautions are important. Ensure that the correct water level remains constant. The patient must not add or discard
water. After the 4-5 days, the bottle with the water must be discarded. The PEP bottle is adjusted to a “closed-lid” concept. This results in less droplet spread; however, the patient should preferably try to do this exercise without people in her/his room. If the patient needs support to blow the PEP bottle, the other party must have proper protective gear. Otherwise use a well-ventilated room/area, or outdoors where achievable.

The PEP bottle is an individualized treatment, so while the patient should not be adding or discarding water, the physio should be grading this. One should start off with lower water levels in the bottle e.g. 5cmH2O and see how this affects the patient’s breathing. If this does not assist them much to lessen the work of breathing, one can slowly increase the water level (by 2cmH2O), provided that the previous water level was not exacerbating symptoms! Increase the water in this manner until you reach a level that helps them to breathe with more ease. Then they can do 5-6 breaths per waking hour during the day as previously discussed. It is important to monitor oxygen saturation using an oximeter, and to communicate your
findings with the patient’s General Practitioner- discussing improvements or worsening of symptoms, so that decisions can be made timeously to continue or discard use of the PEP bottle. If a patient’s symptoms worsen during use, they should stop using the PEP bottle IMMEDIATELY and seek further medical consultation.

The method and the frequency of the regime will be explained to the patient. Again, appropriate social distancing will be maintained. Contra-indications for using the PEP bottle are suspected pneumothorax or untreated high blood pressure.

All Praises are due to God

Primary resource used: Protocol compiled and shared by Physiotherapists within Rietondale Homecare Group.

Link below

Amendments through consultation with Cardiopulmonary Physiotherapist Professors, Doctors and physiotherapist colleagues.

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