Pursed Lip Breathing (or "PLB") is a very popular and excellent "Rescue" technique for the acute dyspnea resulting from COPD, Emphysema and Asthma. However, in some cases of severe COPD and Emphysema, and chronic severe Asthma, it may enhance breathing comfort if used in a chronic long term manner. Generally however, breathing control techniques are more natural and desirable for chronic, long term breathing comfort.

First, you need to understand some traditional theory as to why this technique works. Refresh your memory on the concept of Dynamic Bronchial Compression, and the collapsing of your airways on expiration, as your lungs are getting smaller as you breathe out. And recall that this is a particularly serious problem in people with Emphysema, as the elastic supporting lung structure helping to keep the airways open is deficient.

Pursed Lip Breathing simply imposes a slight obstruction to expiration air flow at the mouth, which generates a back pressure throughout the airways, and therefore a stenting effect to help prop open the airways and assist expiration and lung emptying. It must be emphasized, the amount of pressure supplied by you by pursing your lips together must, as usually described, be "minimal," or "gentle."

Specifically this mouth back pressure must be in the range of only 5 to 10 cm water pressure, and that isn't very much. If you compress your lips too much, and force your exhalation, you will easily exceed this minimal pressure. In so doing you will actually provide an expiration airway obstructive situation and impair your air flow and lung emptying.

As generally taught, breathe in through your nose, to warm and humidify the air, and remove particles and bacteria. Then on expiration, gently pucker your lips together as though you are whistling, to provide the desired mouth back pressure, and breathe out through your pursed lips in a "prolonged" manner. The length of prolongation is often stated to be two or three times (and occasionally four times) longer than inspiration. To practice correct lip pursing people are often instructed to place a candle about 4 to 6 inches away, and to make the flame gently bend or flicker, but never so hard as to blow out the flame.

Practicing in this manner is not very precise as to either mouth pressure or the all important length of expiration. A more realistic and precise way of practicing is by using the Breathing Trainer in conjunction with candle blowing, to be certain the all important long (but not too long) expiration time is correct.

For normal breathing, use your regular Breathing Trainer prescription. For "Rescue" breathing practice from acute overinflation dyspnea, set the Respiratory Rate at least two or three breaths less than your usual, and also set the Inspiration Time 5 or up to 10% less than your usual (i.e. your desired expiration time prolongation will therefore automatically be set 5 to 10% longer). Five or ten breaths of this Rescue pattern should get your lungs deflated, and you can then resume your normal breathing pattern. This Rescue pattern is also a good technique to be used temporarily during exertion, such as hurrying to cross a street or climbing stairs.

There is a common and serious problem with Pursed Lip Breathing, and that is the frequent reaction for people distressed by shortness of breath who preform tight-lipped and straining PLB, and therefore with excessively high PLB back pressures. This will immediately make their breathing situation worse. This is a very tragic paradox, as it is a natural tendancy for people to believe that if PLB works beneficially, then harder PLB will work better. And unfortunately lip puckering in the whistling position makes it very easy to slip into a tight mouth, straining, high pressure type of breathing.

A better solution to this problem is not to make the "whistling pucker," but instead to gently press the center of the lips together, and permit the air to escape through both sides of the lips. To do this more effectively, the cheeks should be relaxed. Doing PLB in this manner it is more difficult to switch into a tight, high pressure PLB situation.

And there is another major advantage to this modified PLB technique. By placing a straw through the central portion of the lips the mouth pressure can now be easily and directly measured with a suitable pressure guage. By watching the guage you are now able to do direct visual biofeedback training to achieve the desired 5 to 10 cm H2O back pressure, and to learn specifically what that correct pressure feels like, and therefore how to sense when you are pursing your lips and exhaling correctly.

This same system can also be used to demonstrate and recognize the common problem of excessive tight-lip, high back pressure PLB, by having the patient strain at 20 to 30 cm H2O, to get the sensation of how not to do PLB. Once you know how to sense this high pressure sensation, it then becomes an easily recognized signal of poor PLB technique that needs correction.

A suitable pressure guage may be obtained at Dwyer Instruments, Inc. for Pursed Lip Breathing training ( http://www.dwyer-inst.com/ --- (Standard Magnehelic& reg; Pressure Gage - Series 2000-25 --- 0 to 25 cm H2O --- 4" dial - Price $66.50). No respiratory clinic or pulmonary physician's office should be without a guage of this type for PLB training purposes.

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We would now like to give you some recent research findings that provide insight as to how PLB works.

This discussion must first recognize the crucial importance of Dynamic Hyperinflation, and the role this phenomenon plays in the generation of dyspnea in COPD patients.

Dynamic Hyperinflation has been recognized for many years, but surprisingly did not generate much research interest until the early-mid 1990's. Since then there has been an explosion of interest, and many excellent research papers have been published. It is now clear that Dynamic Hyperinflation plays a major role in the production of COPD dyspnea, and particularly acute dyspnea attacks. Previously it was thought that airway obstruction was the direct and major reason for dyspnea, but this is not correct. While airway obstruction plays a contributory role in dyspnea, it is now clear that Dynamic Hyperinflation plays a major role, and in some cases the dominant role in causing COPD dyspnea.

Correcting the Dynamic Hyperinflation lesion is now known to be crucially important in relieving dyspnea, and Pursed Lip Breathing is all about correcting Dynamic Hyperinflation.

If you are uncertain about the concept of Dynamic Hyperinflation, go back and read the module on this topic.

Recently some fascinating insight into Pursed Lip Breathing has come from Dr. Roberto Bianchi and colleagues  reference --- (Chest Wall Kinematics and Breathlessness During Pursed-Lip Breathing in Patients with COPD. Bianchi B, Gigliotti F, Romagnoli I, Lanini B, Castellani C, Grazzini M, Scano G - CHEST 2004; 125: 459-465).

This Italian research group used a sophisticated technique of multiple optical sensors placed on the surface of the body to separate breathing movements of the chest and abdomen (i.e. thoracic breathing versus "diaphragmatic breathing") of COPD patients while doing PLB.

This diagram is from their paper.

The middle graph shows chest movement, and the lower graph abdominal (mainly diaphragmatic) movement.

The upper graph is the summed movement of overall breathing. Focus on this graph. Inspiration is going up, and expiration going down.

On the left, the small excursions reflect regular quiet breathing ("QB") in and out.

Note that immediately on starting Pursed Lip Breathing expiration becomes much prolonged, and after breathing in again the result is a much slower, and larger (and therefore more efficient) alveolar ventilation breath.

This graphically shows why you can obtain prompt breathing relief using PLB.

And note carefully, this PLB breathing pattern is exactly the same breathing pattern we have been instructing you for efficient COPD breathing, namely, a slow, deep breath, with a long expiration phase.

This raises the interesting question of why Pursed Lip Breathing works. Is it due to the traditional theory of expiration back pressure and airway stenting support of the airways on expiration, or, is it due to the induction of of a particular type of breathing pattern? Or perhaps a combination of the two? My personal opinion in this matter is, the probable dominant effect is the induced change in breathing pattern, caused simply because a low mouth pressure will naturally take a longer expiration time to perform, and therefore a natural slowing of the respiratory rate. I suspect the traditional back pressure / airway stenting theory plays only a relatively minor part in PLB dyspnea relief. Further research is needed to resolve this question.

In my personal practice I did not teach PLB very often, and in fact if patients referred to me were doing PLB I usually asked them to stop it. I did this because I found it was more natural and easier for patients to use breathing control techniques to help their chronic dyspnea problems, and by focusing on breathing patterns I could fine tune their Breathing Prescriptions for greater efficiency.

However, I did sometimes use both acute and chronic Pursed Lip Breathing, mainly as an advanced technique, usually in patients with very severe Emphysema, as it did appear to give some additional measure of improved comfort. And some patients did indeed find that PLB was a useful adjunct to their breathing control techniques for exercising, and for acute dyspnea attacks.

Turning again to the diagram, a serious weakness of the traditional Pursed Lip Breathing technique is revealed. Note carefully that on inspiration the patients breath volume returns to almost the exact same starting point. While lung deflation has certainly occurred during that breath, on breathing in again the patient returns to the same overinflation point, and therefore has to start lung deflation all over again.

The solution to this problem is the Inspiration Limitation Technique we described previously. For at least three to five breaths in a row, the overinflated patient should limit their inspiration effort to about 75 to 80% of what they would normally inhale. This will progressively deflate the lungs. By then they should be properly deflated, and patients can then again resume their regular breathing pattern.

The diagram also reveals another very interesting observation. Note that all of the breaths, other than the last one, have an abrupt transition between inspiration and expiration. Is this important? I believe probably so, and this relates to the observation in 1963 by Dr. H L Motley that slow, deep breathing improved the oxygenation levels in COPD patients. Studies have shown that PLB may often improve blood Oxygen Saturation levels in the 4 to 4.5 percent range, and there are anecdotal reports of improvements in the 8 percent range in some severely hypoxic patients.

The only way this could have happened was for fresh oxygen rich air to have come in contact with poorly ventilating alveoli that had a good blood supply to pick up that oxygen. The process is known technically as Ventilation / Perfusion Matching, (also known as "V/Q Matching"), and it occurs mostly in communications within the lung tissue itself, between the alveoli, known as the Pores of Kohn. The End-Inspiration Pause will provide increased time for better fresh air circulation at the alveolar level, and therefore better blood oxygenation.

Yes, the End-Inspiration Pause in the Breathing Trainer is important, at least in some patients. Adjusting the End-Inspiration Pause while monitoring with Oximeters assessing blood oxygen levels should be considered in all patients, and definitely in those patients requiring long term oxygen therapy.

Should End-Expiration breathing training result in only 1 to 2% improvements in blood Oxygen Saturation levels there are significant potential therapy, and economic benefits, as oxygen is expensive.

We await further research to see if this abrupt inspiration / expiration transition in PLB is confirmed in a larger series of COPD patients, and if End-Expiration pause breathing training can significantly improve Oxygen Saturation levels.

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