Schans, Cornelis Peter van der

English

The use of physiotherapeutic techniques may increase mucus transport in patients with airways disease including COPD, asthma, cystic fibrosis and primary ciliary dyskinesia. The most effective parts of the treatment are probably forced expirations with open glottis and coughing. However, in patients with decreased elastic recoil pressure of the lung tissue the effect of these measures is limited as a result of bronchial collapse. In these patients the bronchial collapse can be reduced by a positive expiratory pressure breathing. ... Zie: Summar

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   University of GroningenPhysiotherapy and bronchial mucus transportSchans, Cornelis Peter van derIMPORTANT NOTE: You are advised to consult the publisher's version (publisher's PDF) if you wish to cite fromit. Please check the document version below.Document VersionPublisher's PDF, also known as Version of recordPublication date:1991Link to publication in University of Groningen/UMCG research databaseCitation for published version (APA):Schans, C. P. V. D. (1991). Physiotherapy and bronchial mucus transport. s.n.CopyrightOther than for strictly personal use, it is not permitted to download or to forward/distribute the text or part of it without the consent of theauthor(s) and/or copyright holder(s), unless the work is under an open content license (like Creative Commons).The publication may also be distributed here under the terms of Article 25fa of the Dutch Copyright Act, indicated by the “Taverne” license.More information can be found on the University of Groningen website: https://www.rug.nl/library/open-access/self-archiving-pure/taverne-amendment.Take-down policyIf you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediatelyand investigate your claim.Downloaded from the University of Groningen/UMCG research database (Pure): http://www.rug.nl/research/portal. For technical reasons thenumber of authors shown on this cover page is limited to 10 maximum.Download date: 13-02-2023The airways are effectively protected against inhaled particles by the productionand subsequently continuous transport of mucus in the airways. However,retention of mucus in the lungs is a wellknown phenomenon in patients withairways disease, such as chronic obstructive pulmonary disease, cystic fibrosisand primary ciliary dyskinesia. Mucus retention may contribute to thedevelopment of respiratory tract infections and may also increase airflowobstruction. Retention of mucus is usually treated symptomatically by theapplication of physiotherapeutic techniques in an attempt to increase mucustransport. Some of these techniques such as manual percussion and posturaldrainage have been used for years, based upon the clinical impression that theyimprove mucus transport or make expectoration easier. Manual percussion onthe thorax is thought to increase mucus transport in the airways by theexternally applied vibrations. In case of postural drainage it is assumed thatgravitational force will support transport of mucus. Other more recentlyintroduced techniques, including the forced expiration technique and positiveexpiratory pressure breathing, are based upon data obtained by physiologicalknowledge or hypotheses. In case of the forced expiration technique a forcedexpiration is performed with an open glottis at different lung volumes. Thistechnique is based on the hypothesis that a high expiratory airflow velocity willarise in the airways due to a combination of a high expiratory flow and a smalldiameter due to a dynamic compression of the airways. Positive expiratorypressure breathing, during which the patient is asked to breath with anexpiratory mouth pressure of 10-20 cm HrO, is based upon the hypothesis thatit increases the quantity of air behind mucus plugs and consequentlyexpectoration by coughing or forced expiration will be more effective.The effect of physiotherapeutic measures is clinically difficult to judge, becauseoften a combination of several techniques is applied and no reliable, easy tohandle assessment is available that reflects transport of mucus. In this thesisthe effects of several physiotherapeutic measures, applied to improve mucustransport in the airways, are described. In order to investigate mucus transportand the effect of physiotherapeutic measures we developed an objectivetechnique to quantit/ mucus transport.129Mucus transport in the lower respiratory tract.Mucus is produced throughout the bronchial tree and is continuouslytransported in the direction of the oropharyrx. The different mechanisms ofmucus transport in healthy subjects and in patients with airways disease arediscussed in Chapter 2. In healthy subjects mucus transport in the lowerrespiratory tract is mainly taking place by cilia activity and expiratory airflow.Ciliated cells are found in the airways, from the trachea as far as the terminalbronchioles. The cilia beat continuously and have an effective beat duringwhich mucus is "pushed" in the direction of the oropharynx. The recovery beattakes place in the direction of the alveoli; during this phase no transport takesplace. The capacity of transport by cilia activity depends among other factorson the quantity of ciliated cells, which is directly related to the total airwaysurface at a given level in the bronchial tree. The effectivity of mucus transportby cilia beating, therefore, decreases from the peripheral airways, which have alarge total airway surface, to the central airways, which have a much smallertotal airway surface. The effectivity of transport by expiratory airflow is mainlydependent on expiratory airflow velocity. Mucus transport by expiratory airflow,therefore, is probably less effective in the peripheral airways, in which theairflow velocity is low due to a large total airway diameter, than in the centralairways, in which the airflow velocity is much higher due to a much smallertotal airway diameter.In patients with airways disease i.e. chronic obstructive pulmonary disease,asthma, cystic fibrosis, and primary ciliary dyskinesia, retention of mucus iswellknown and may be caused by hypersecretion in combination with impairedmucus transport. Mucus transport is impaired due to reduced cilia activity as aresult of respiratory tract infections and hypersecretion. Although expiratoryairflow is often decreased, due to an obstruction of the airways, it is likely thatforced expirations and coughing become the most important mechanisms tocompensate tlre decreased mucociliary transport.Measurement of mucus transport.The effectivity of measures to improve mucus transport is by some authorsinvestigated using lung function measurements, representing ventilatoryparameters, or gas exchange measurements using arterial bloodgas analysis.130and is continuously:erent mechanisms ofr airways disease arernsport in the lowernd expiratory airflow.as far as the terminaleffective beat duringnx. The recovery beatlse no transport takesi among other factorsd to the total airwayity of mucus transportairways, which have ahave a much smallerltory airflow is mainly. by expiratory airflow,airways, in which theer, than in the central[e to a much smaller,e pulmonary disease,retention of mucus isbination with impaireduced cilia activity as ar. Although expiratorydrways, it is likely thatrortant mechanisms tort is by some authorspresenting ventilatory:rial bloodgas analysis.There is however no direct relationship between mucus transport and theseparameters. Therefore these parameters are in fact not suitable to evaluatemethods to improve mucus transport. In Chapter 3 diiferent methods whichdirectly or indirectly reflect mucus transport are discussed. Measurement ofmucus transport by a radioactive aerosol tracer technique is probably the bestmethod to investigate the effectivity of physiotherapeutic measures applied toincrease mucus transport. In our investigations we used ehTc-Íin colloid astracer, which was nebulised by an intermittent positive pressure respirator. Thetracer was subsequently inhaled by the subjects. Deposition of the tracer in theairways, and clearance from the airways was recorded using a gamma camera.Mucus transport, measured by registration of the clearance of the radioactiveaerosol tracer, and the repeatability of this method, was investigated in a groupof healthy volunteers, and described in chapter 3. Mucus transport, measuredfor 45 minutes using this method, was about 5 % of the initial amount oftracer, which is lower than usually described in the literature. This can beexplained by a more peripheral deposition of the tracer we used. It may alsobe explained by the fact that our data were not corrected for alveolardeposition; the initial amount of deposition in the peripheral lung region istherefore higher, and as a consequence the decrease in percentage of the initialamount is smaller.Effect of manual percussion.Manual percussion is a wellknown part of physiotherapy and is based upon theassumption that percussion on the thorax will produce vibrations in the lungsupporting mucus transport. In Chapter 4 the results of a study on the efïrct ofmanual percussion on mucus transport are described in patients with chronicobstructive pulmonary disease and excessive tracheobronchial secretions. Theeffect of manual percussion as a single procedure and in combination withpostural drainage, breathing exercises and coughing was compared to atreatment that consisted of postural drainage, breathing exercises and coughing,but without manual percussion. Manual percussion as a single procedureresulted in a small but statistically significant increase of mucus transport.Manual percussion in combination with postural drainage, coughing, andbreathing exercises, however, resulted in a much greater improvement of mucustransport, which was similar to the effect of a combination of postural drainage,t37coughing and breathing exercises but without manual percussion. It is thereforeconcluded that the most effective part of a physiotherapeutic treatment is acombination of coughing, breathing exercises and postural drainage. Manualpercussion apparently does not enhance the effectiveness of a combination ofcoughing, breathing exercises and postural drainage. Only when these methodscan not be effectively applied it should be considered to apply manualpercussion.Influence of elastic recoil pressure on the effect of forced expirations.Forced expirations and coughing are probably the most importantphysiotherapeutic measures to increase mucus transport. During forcedexpirations or coughing mucus is transported in the direction of the oropharynxby the high expiratory airflow velocity, which is the result of a high airflow anda dynamic compression of the airways. Patients with pulmonary emphysemahave a loss of elastic recoil pressure of the lung tissue. In these circumstancesthe dynamic compression of the airways during forced expiration may result ina complete airway collapse and thereby limit the effectiveness of the forcedexpirations and coughing. In Chapter 5 the results of a study on the influenceof elastic recoil pressure on spontaneous mucus clearance and the effectivenessof forced expirations and coughing are described. In patients with decreasedelastic recoil pressure spontaneous mucus clearance appeared to be higher ascompared to patients with normal elastic recoil pressure with comparable levelof airflow obstruction as measured by FEt. Mucus transport data in thesepatients, however, may not be completely comparable with those of healthysubjects, because of differences in deposition pattern of the tracer. Patientswith reduced elastic recoil pressure may have normal mucus transport rates, incontrast to patients with normal elastic recoil pressure. It is not known why inpatients with emphysema mucus transport is better preserved than in patientswith chronic bronchitis. In patients with normal elastic recoil pressure, but notin those with decreased elastic recoil pressure, mucus clearance could beenhanced by forced expirations and coughing. The bronchial collapse that arisesin patients with decreased elastic recoil pressure during a forced expiration islikely to be responsible for the limited effect of forced expirations in theseDatients.Effect of exThe resultsmay have ndisease. Mseverely rershown in (reduced muexpiration.(MEFV)-cu:lung volumeMany patierpressure brrsubjective bbreathing rpressure. Aof the MEFpressure breemphysemachange the rthe collapseresistance atthese lung vlung capacit'expiratory plower lungMEFV-curvefor patients 'Effect of pomucus cleariIn patientsobstruct smaairways as lcVelocity of iI J Llssion. It is thereforeeutic treatment is aal drainage. Manualof a combination ofwhen these methodsd to apply manualxpirations.re most important)ort. During forcedon of the oropharyrxof a high airflow andrlmonary emphysemar these circumstancesriration may result inveness of the forcedtudy on the influenceand the effectivenesstients with decreasedared to be higher asvith comparable levelLnsport data in thesegith those of healthyI the tracer. Patients)us transport rates, inis not known why inrved than in patientscoil pressure, but notclearance could beal collapse that arisesa forced expiration is. expirations in theseEffect of expiratory resistance on airway collapse.The results of earlier studies suggest that patients with pulmonary emphysemamay have normal or slightly reduced mucus transport in a stable phase of theirdisease. Mucus transport during a pulmonary infection, however, may beseverely reduced by inhibition of ciliary activity and by hypersecretion. Asshown in Chapter 5, forced expirations are ineffective in compensating thereduced mucus transport in case of a collapse of the airways during a forcedexpiration. This collapse is visible in the maximal expiratory flow volume(MEFV)-curve as a sharp bend convex to the volume axis at relatively highlung volume.Many patients with emphysema spontaneously use a form of positive expiratorypressure breathing, i.e. pursed lips breathing. They often ciaim an immediatesubjective benefit. It has been hypothesized that positive expiratory pressurebreathing reduces airway collapse by an increase of the intra-bronchialpressure. A reduction of airway collapse should be visible in the configurationof the MEFV curve. In Chapter 6 a study on the effect of positive expiratorypressure breathing on the configuration of the MEFV curve in patients withemphysema is described. Positive expiratory pressure breathing was shown tochange the configuration of the MEFV-curve in some patients in the sense thatthe collapse phenomenen was diminished. This indicates that the airwayresistance at high lung volumes was reduced, resulting in an increased flow atthese lung volumes. This effect was inversely correlated to the predicted totallung capacity. In patients with a severely increased total iung capacity positiveexpiratory pressure breathing did not reduce the collapse phenomenen. Atlower lung volumes no effect was seen on the configuration of theMEFV-curve. An expiratory resistance during forced expiration is to be advisedfor patients with airway collapse but without severe chronic hyperinflation.Effect of positive expiratory pressure breathing on pulmonary function andmucus clearance in patients with cystic fibrosis.In patients with cystic fibrosis tenacious respiratory tract secretions oftenobstruct small peripheral airways. Mucus mobilisation is very difficult in theseairways as local airflow velocity is low due to the huge total airway diameter.Velocity of airflow may be further reduced by the development of atelectasis,I J JIas a result of obstruction by mucus plugs. It has been hypothesized that anincrease cf expiratory mouth pressure will increase the volume of air behindmucus plugs. Mucus plugs may be subsequently mobilised by a forcedexpiration. Breathing with an expiratory pressure may increase the pressuregradient between open and closed alveoli. It may also reduce airway resistancein peripheral and collateral airways by an increase of functional residualcapacity. Both mechanisms may lead to an increase of air volume in closedalveoli. An increase of air volume in closed alveoli should be visible as anincreased thoracic gas volume (TGV). In Chapter 7 the results of a study onthe effect of positive expiratory pressure breathing on pulmonary function andmucus clearance in patients with cystic fibrosis are presented. During positiveexpiratory pressure breathing TGV increased significantly. However, afterdiscontinuation of the positive expiratory pressure TGV returned rapidly to thebaseline value. Positive expiratory pressure appeared to have no influence onspontaneous mucus transport or mucus transport by coughing. Positiveexpiratory pressure breathing can therefore not be recommended as a therapyto improve mucus transport, but may be useful in case of acute atelectasis.CONCLUSION.The use of physiotherapeutic techniques may increase mucus transport inpatients with airways disease including COPD, asthma, cystic fibrosis andprimary ciliary dyskinesia. The most effective parts of the treatment areprobably forced expirations with open glottis and coughing. However, inpatients with decreased elastic recoil pressure of the lung tissue the effect ofthese measures is limited as a result of bronchial collapse. In these patients thebronchial collapse can be reduced by a positive expiratory pressure breathing.It should be considered to apply manual percussion only when posturaldrainage, breathing exercises and forced expirations are ineffective. Positiveexpiratory pressure breathing in patients with cystic fibrosis is shown to increaselung volume and may therefore be useful in case of acute atelectasis. It had,however, no influence on mucus transport in these patients.The choice of physiotherapeutic techniques should be dependent on thepathophysiological mechanisms in the airways of the patient. A referral to aI J +physi,airwainforrFurthphysirpathoretenltechn;mechiphysictheralbeenprognstudieypothesized that anllume of air behindilised by a forcedcrease the pressurerce airway resistancefunctional residualir volume in closedild be visible as anesults of a study onnonary function andLted. During positivetly. However, afterurned rapidly to theave no influence oncoughing. Positiverended as a therapycute atelectasis.mucus transport incystic fibrosis andthe treatment areghing. However, intissue the effect ofIn these patients ther pressure breathing.only when posturalineffective. Positiveis shown to increasee atelectasis. It had,dependent on thelnt. A referral to aphysiotherapist, therefore, should contain sufficient information about theairway mechanics. Physiotherapists should be capable to interpret thisinformation.Further studies are needed to investigate the physiological effects ofphysiotherapeutic measures, aiming an increase in mucus transport, in differentpathophysiological conditions contributing to the development of mucusretention. Understanding of the relationship between physiotherapeutictechniques, in the treatment of mucus retention, and pathophysiologicalmechanisms present in the airways may increase the effectiveness ofphysiotherapy as it provides a base for an individual choice and application oftherapy. In this thesis short-term effects of physiotherapeutic treatment havebeen investigated. However, long-term effects of these techniques on theprognosis of the disease and the frequency of exacerbations still remains to bestudied.135

Physiotherapy and bronchial mucus transport

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Physiotherapy and bronchial mucus transport

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