https://doi.org/10.4081/monaldi.2021.1499
Secretion management in patients with ineffective airway clearance with non-invasive mechanical ventilation use: Expert guidance for clinical practice
Submitted: July 11, 2020
Accepted: April 17, 2021
Published: June 7, 2021
Accepted: April 17, 2021
Abstract Views: 5425
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All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article or claim that may be made by its manufacturer is not guaranteed or endorsed by the publisher.
Authors
Non-invasive ventilation (NIV) is a mainstay of management of chronic respiratory failure in many disorders which are known to cause abnormal airway secretion clearance. Currently, there is no guidance regarding either the secretion handling during NIV use or the role of NIV in secretion management in these patients. The aim of this document was to provide an overview of the various techniques available in the management of respiratory secretions and their use in conjunction with NIV. Literature search was performed using the keywords, “(secretion OR secretions) AND (noninvasive ventilation OR NIV)” on PubMed and EMBASE. The search yielded 1681 and 509 titles from PubMed and EMBASE, respectively. After screening, 19 articles were included in this review. Suggestions of the expert panel were formulated by mutual consensus after reviewing the relevant literature. The draft of the expert panel’s suggestions was circulated among all authors via electronic mail for comments. Any conflicts were resolved by mutual discussion to achieve agreement. The final document was approved by all. This document by the International Network for Airway Secretions Management in NIV describes various airway secretion clearance techniques. It provides the expert panel’s suggestions for the use of these techniques in conjunction with NIV for patients with muco-obstructive and neuromuscular disorders.
Button B, Goodell HP, Atieh E, et al. Roles of mucus adhesion and cohesion in cough clearance. Proc Natl Acad Sci USA 2018 04;115:12501–6.
DOI: https://doi.org/10.1073/pnas.1811787115
Bach JR. Amyotrophic lateral sclerosis: prolongation of life by noninvasive respiratory AIDS. Chest 2002;122:92–8.
DOI: https://doi.org/10.1378/chest.122.1.92
Madden BP, Kariyawasam H, Siddiqi AJ, et al. Noninvasive ventilation in cystic fibrosis patients with acute or chronic respiratory failure. Eur Respir J 2002;19:310–3.
DOI: https://doi.org/10.1183/09031936.02.00218502
Boucher RC. Muco-Obstructive Lung Diseases. N Engl J Med 2019;380:1941–53.
DOI: https://doi.org/10.1056/NEJMra1813799
Chatwin M, Toussaint M, Gonçalves MR, et al. Airway clearance techniques in neuromuscular disorders: A state of the art review. Respir Med 2018;136:98–110.
DOI: https://doi.org/10.1016/j.rmed.2018.01.012
Bach JR. Secretion management must be considered when reporting success or failure of noninvasive ventilation. Chest 2003;123:1773–4.
DOI: https://doi.org/10.1016/S0012-3692(15)33744-2
Fauroux B, Boulé M, Lofaso F, et al. Chest physiotherapy in cystic fibrosis: improved tolerance with nasal pressure support ventilation. Pediatrics 1999;103:E32.
Gomez-Merino E, Bach JR. Duchenne muscular dystrophy: prolongation of life by noninvasive ventilation and mechanically assisted coughing. Am J Phys Med Rehabil 2002;81:411–5.
DOI: https://doi.org/10.1097/00002060-200206000-00003
McIlwaine M, Bradley J, Elborn JS, Moran F. Personalising airway clearance in chronic lung disease. Eur Respir Rev 2017;26: 160086.
DOI: https://doi.org/10.1183/16000617.0086-2016
Rodrigues PR, Brito PU, Fernandes L, et al. Peak cough flow measurement with a pneumotacograph and a portable peak flow meter in patients with neuromuscular diseases. Rev Port Pneumol 2017;23:39–40.
DOI: https://doi.org/10.1016/j.rppnen.2016.08.003
Bach JR, Campagnolo DI, Hoeman S. Life satisfaction of individuals with Duchenne muscular dystrophy using long-term mechanical ventilatory support. Am J Phys Med Rehabil 1991;70:129–35.
DOI: https://doi.org/10.1097/00002060-199106000-00004
Benditt JO. Respiratory Care of Patients With Neuromuscular Disease. Respir Care 2019;64:679–88.
DOI: https://doi.org/10.4187/respcare.06827
Dohna-Schwake C, Ragette R, Teschler H, Voit T, Mellies U. IPPB-assisted coughing in neuromuscular disorders. Pediatr Pulmonol 2006;41:551–7.
DOI: https://doi.org/10.1002/ppul.20406
Mellies U, Goebel C. Optimum insufflation capacity and peak cough flow in neuromuscular disorders. Ann Am Thorac Soc 2014;11:1560–8.
DOI: https://doi.org/10.1513/AnnalsATS.201406-264OC
Hull J, Aniapravan R, Chan E, et al. British Thoracic Society guideline for respiratory management of children with neuromuscular weakness. Thorax 2012;67:i1-40.
DOI: https://doi.org/10.1136/thoraxjnl-2012-201964
Toussaint M, Boitano LJ, Gathot V, et al. Limits of effective cough-augmentation techniques in patients with neuromuscular disease. Respir Care 2009;54:359–66.
Ishikawa Y, Bach JR, Komaroff E, et al. Cough augmentation in Duchenne muscular dystrophy. Am J Phys Med Rehabil 2008;87:726–30.
DOI: https://doi.org/10.1097/PHM.0b013e31817f99a8
Brito MF, Moreira GA, Pradella-Hallinan M, Tufik S. Air stacking and chest compression increase peak cough flow in patients with Duchenne muscular dystrophy. J Bras Pneumol 2009;35:973–9.
DOI: https://doi.org/10.1590/S1806-37132009001000005
Toussaint M, Pernet K, Steens M, et al. Cough augmentation in subjects with Duchenne muscular dystrophy: Comparison of air stacking via a resuscitator bag versus mechanical ventilation. Respir Care 2016;61:61–7.
DOI: https://doi.org/10.4187/respcare.04033
Bach JR. Mechanical insufflation-exsufflation. Comparison of peak expiratory flows with manually assisted and unassisted coughing techniques. Chest 1993;104:1553–62.
DOI: https://doi.org/10.1378/chest.104.5.1553
Bianchi C, Carrara R, Khirani S, Tuccio MC. Independent cough flow augmentation by glossopharyngeal breathing plus table thrust in muscular dystrophy. Am J Phys Med Rehabil 2014;93:43–8.
DOI: https://doi.org/10.1097/PHM.0b013e3182975bfa
Morrow B, Zampoli M, van Aswegen H, Argent A. Mechanical insufflation-exsufflation for people with neuromuscular disorders. Cochrane Database Syst Rev 2013;(12):CD010044.
DOI: https://doi.org/10.1002/14651858.CD010044.pub2
Chatwin M, Simonds AK. The addition of mechanical insufflation/exsufflation shortens airway-clearance sessions in neuromuscular patients with chest infection. Respir Care 2009;54:1473–9.
Vitacca M, Paneroni M, Trainini D, et al. At home and on demand mechanical cough assistance program for patients with amyotrophic lateral sclerosis. Am J Phys Med Rehabil 2010;89:401–6.
DOI: https://doi.org/10.1097/PHM.0b013e3181d89760
Chatwin M, Ross E, Hart N, et al. Cough augmentation with mechanical insufflation/exsufflation in patients with neuromuscular weakness. Eur Respir J 2003;21:502–8.
DOI: https://doi.org/10.1183/09031936.03.00048102
Senent C, Golmard J-L, Salachas F, et al. A comparison of assisted cough techniques in stable patients with severe respiratory insufficiency due to amyotrophic lateral sclerosis. Amyotroph Lateral Scler 2011;12:26–32.
DOI: https://doi.org/10.3109/17482968.2010.535541
Sancho J, Servera E, Díaz J, Marín J. Efficacy of mechanical insufflation-exsufflation in medically stable patients with amyotrophic lateral sclerosis. Chest 2004;125:1400–5.
DOI: https://doi.org/10.1378/chest.125.4.1400
Guérin C, Bourdin G, Leray V, et al. Performance of the coughassist insufflation-exsufflation device in the presence of an endotracheal tube or tracheostomy tube: a bench study. Respir Care 2011;56:1108–14.
DOI: https://doi.org/10.4187/respcare.01121
Chatwin M, Bush A, Simonds AK. Outcome of goal-directed non-invasive ventilation and mechanical insufflation/exsufflation in spinal muscular atrophy type I. Arch Dis Child 2011;96:426–32.
DOI: https://doi.org/10.1136/adc.2009.177832
Miske LJ, Hickey EM, Kolb SM, et al. Use of the mechanical in-exsufflator in pediatric patients with neuromuscular disease and impaired cough. Chest 2004;125:1406–12.
DOI: https://doi.org/10.1378/chest.125.4.1406
Rafiq MK, Bradburn M, Proctor AR, et al. A preliminary randomized trial of the mechanical insufflator-exsufflator versus breath-stacking technique in patients with amyotrophic lateral sclerosis. Amyotroph Lateral Scler Frontotemporal Degener 2015;16:448–55.
DOI: https://doi.org/10.3109/21678421.2015.1051992
Mahede T, Davis G, Rutkay A, et al. Use of mechanical airway clearance devices in the home by people with neuromuscular disorders: effects on health service use and lifestyle benefits. Orphanet J Rare Dis 2015;10:54.
DOI: https://doi.org/10.1186/s13023-015-0267-0
Travlos V, Drew K, Patman S. The value of the CoughAssist® in the daily lives of children with neuromuscular disorders: Experiences of families, children and physiotherapists. Dev Neurorehabil 2016;19:321–6.
Moran FC, Spittle AJ, Delany C. Lifestyle implications of home mechanical insufflation-exsufflation for children with neuromuscular disease and their families. Respir Care 2015;60:967–74.
DOI: https://doi.org/10.4187/respcare.03641
Crescimanno G, Marrone O. High frequency chest wall oscillation plus mechanical in-exsufflation in Duchenne muscular dystrophy with respiratory complications related to pandemic Influenza A/H1N1. Rev Port Pneumol 2010;16:912–6.
DOI: https://doi.org/10.1016/S2173-5115(10)70009-9
Birnkrant DJ, Pope JF, Lewarski J, et al. Persistent pulmonary consolidation treated with intrapulmonary percussive ventilation: a preliminary report. Pediatr Pulmonol 1996;21:246–9.
DOI: https://doi.org/10.1002/(SICI)1099-0496(199604)21:4<246::AID-PPUL8>3.0.CO;2-M
Yuan N, Kane P, Shelton K, et al. Safety, tolerability, and efficacy of high-frequency chest wall oscillation in pediatric patients with cerebral palsy and neuromuscular diseases: an exploratory randomized controlled trial. J Child Neurol 2010;25:815–21.
DOI: https://doi.org/10.1177/0883073809350223
Chaisson KM, Walsh S, Simmons Z, Vender RL. A clinical pilot study: high frequency chest wall oscillation airway clearance in patients with amyotrophic lateral sclerosis. Amyotroph Lateral Scler 2006;7:107–11.
DOI: https://doi.org/10.1080/14660820600640570
Lechtzin N, Wolfe LF, Frick KD. The impact of high-frequency chest wall oscillation on healthcare use in patients with neuromuscular diseases. Ann Am Thorac Soc 2016;13:904–9.
DOI: https://doi.org/10.1513/AnnalsATS.201509-597OC
Reardon CC, Christiansen D, Barnett ED, Cabral HJ. Intrapulmonary percussive ventilation vs incentive spirometry for children with neuromuscular disease. Arch Pediatr Adolesc Med 2005;159:526–31.
DOI: https://doi.org/10.1001/archpedi.159.6.526
Donaldson SH, Boucher RC. Update on pathogenesis of cystic fibrosis lung disease. Curr Opin Pulm Med 2003;9:486–91.
DOI: https://doi.org/10.1097/00063198-200311000-00007
Muhlebach MS, Zorn BT, Esther CR, et al. Initial acquisition and succession of the cystic fibrosis lung microbiome is associated with disease progression in infants and preschool children. PLoS Pathog 2018;14:e1006798.
DOI: https://doi.org/10.1371/journal.ppat.1006798
McCarren B, Alison JA. Physiological effects of vibration in subjects with cystic fibrosis. Eur Respir J 2006;27:1204–9.
DOI: https://doi.org/10.1183/09031936.06.00083605
Wong JW, Keens TG, Wannamaker EM, et al. Effects of gravity on tracheal mucus transport rates in normal subjects and in patients with cystic fibrosis. Pediatrics 1977;60:146–52.
Herrero-Cortina B, Vilaró J, Martí D, et al. Short-term effects of three slow expiratory airway clearance techniques in patients with bronchiectasis: a randomised crossover trial. Physiotherapy 2016;102:357–64.
DOI: https://doi.org/10.1016/j.physio.2015.07.005
Miller S, Hall DO, Clayton CB, Nelson R. Chest physiotherapy in cystic fibrosis: a comparative study of autogenic drainage and the active cycle of breathing techniques with postural drainage. Thorax 1995;50:165–9.
DOI: https://doi.org/10.1136/thx.50.2.165
Groth S, Stafanger G, Dirksen H, et al. Positive expiratory pressure (PEP-mask) physiotherapy improves ventilation and reduces volume of trapped gas in cystic fibrosis. Bull Eur Physiopathol Respir 1985;21:339–43.
App EM, Kieselmann R, Reinhardt D, et al. Sputum rheology changes in cystic fibrosis lung disease following two different types of physiotherapy: flutter vs autogenic drainage. Chest 1998;114:171–7.
DOI: https://doi.org/10.1378/chest.114.1.171
Dosman CF, Zuberbuhler PC, Tabak JI, Jones RL. Effects of positive end-expiratory pressure on oscillated volume during high frequency chest compression in children with cystic fibrosis. Can Respir J 2003;10:94–8.
DOI: https://doi.org/10.1155/2003/792917
Sontag MK, Quittner AL, Modi AC, et al. Lessons learned from a randomized trial of airway secretion clearance techniques in cystic fibrosis. Pediatr Pulmonol 2010;45:291–300.
DOI: https://doi.org/10.1002/ppul.21179
McIlwaine MP, Alarie N, Davidson GF, et al. Long-term multicentre randomised controlled study of high frequency chest wall oscillation versus positive expiratory pressure mask in cystic fibrosis. Thorax 2013;68:746–51.
DOI: https://doi.org/10.1136/thoraxjnl-2012-202915
Darbee JC, Kanga JF, Ohtake PJ. Physiologic evidence for high-frequency chest wall oscillation and positive expiratory pressure breathing in hospitalized subjects with cystic fibrosis. Phys Ther 2005;85:1278–89.
DOI: https://doi.org/10.1093/ptj/85.12.1278
Reychler G, Debier E, Contal O, Audag N. Intrapulmonary percussive ventilation as an airway clearance technique in subjects with chronic obstructive airway diseases. Respir Care 2018;63:620–31.
DOI: https://doi.org/10.4187/respcare.05876
Rodriguez Hortal MC, Nygren-Bonnier M, Hjelte L. Non-invasive ventilation as airway clearance technique in cystic fibrosis. Physiother Res Int J Res Clin Phys Ther 2017;22:e1667.
DOI: https://doi.org/10.1002/pri.1667
Holland AE, Denehy L, Ntoumenopoulos G, et al. Non-invasive ventilation assists chest physiotherapy in adults with acute exacerbations of cystic fibrosis. Thorax 2003;58:880–4.
DOI: https://doi.org/10.1136/thorax.58.10.880
Placidi G, Cornacchia M, Polese G, et al. Chest physiotherapy with positive airway pressure: a pilot study of short-term effects on sputum clearance in patients with cystic fibrosis and severe airway obstruction. Respir Care 2006;51:1145–53.
Dwyer TJ, Robbins L, Kelly P, et al. Non-invasive ventilation used as an adjunct to airway clearance treatments improves lung function during an acute exacerbation of cystic fibrosis: a randomised trial. J Physiother 2015;61:142–7.
DOI: https://doi.org/10.1016/j.jphys.2015.05.019
Young AC, Wilson JW, Kotsimbos TC, Naughton MT. Randomised placebo controlled trial of non-invasive ventilation for hypercapnia in cystic fibrosis. Thorax 2008;63:72–7.
DOI: https://doi.org/10.1136/thx.2007.082602
Milross MA, Piper AJ, Dwyer TJ, et al. Non-invasive ventilation versus oxygen therapy in cystic fibrosis: A 12-month randomized trial. Respirology 2019;24:1191-7.
DOI: https://doi.org/10.1111/resp.13604
Gaynor M, Wood J. Mechanical insufflation-exsufflation for airway clearance in adults with cystic fibrosis. Respirol Case Rep 2018;6:e00307.
DOI: https://doi.org/10.1002/rcr2.307
Dentice RL, Elkins MR, Bye PTP. Adults with cystic fibrosis prefer hypertonic saline before or during airway clearance techniques: a randomised crossover trial. J Physiother 2012;58:33–40.
DOI: https://doi.org/10.1016/S1836-9553(12)70070-X
Orlik T, Sands D. Application of positive expiratory pressure *PEP* in cystic fibrosis patient inhalations. Dev Period Med 2015;19:50–9.
Kesimer M, Ford AA, Ceppe A, et al. Airway mucin concentration as a marker of chronic bronchitis. N Engl J Med 2017;377:911–22.
DOI: https://doi.org/10.1056/NEJMoa1701632
Clunes LA, Davies CM, Coakley RD, et al. Cigarette smoke exposure induces CFTR internalization and insolubility, leading to airway surface liquid dehydration. FASEB J 2012;26:533–45.
DOI: https://doi.org/10.1096/fj.11-192377
Murphy TF, Brauer AL, Eschberger K, et al. Pseudomonas aeruginosa in chronic obstructive pulmonary disease. Am J Respir Crit Care Med 2008;177:853–60.
DOI: https://doi.org/10.1164/rccm.200709-1413OC
Martinez-Garcia MA, Miravitlles M. Bronchiectasis in COPD patients: more than a comorbidity? Int J Chron Obstruct Pulmon Dis 2017;12:1401–11.
DOI: https://doi.org/10.2147/COPD.S132961
Martins JA, Dornelas de Andrade A, Britto RR, et al. Effect of slow expiration with glottis opened in lateral posture (ELTGOL) on mucus clearance in stable patients with chronic bronchitis. Respir Care 2012;57:420–6.
DOI: https://doi.org/10.4187/respcare.01082
Savci S, Ince DI, Arikan H. A comparison of autogenic drainage and the active cycle of breathing techniques in patients with chronic obstructive pulmonary diseases. J Cardpulm Rehabil 2000;20:37–43.
DOI: https://doi.org/10.1097/00008483-200001000-00006
Chakravorty I, Chahal K, Austin G. A pilot study of the impact of high-frequency chest wall oscillation in chronic obstructive pulmonary disease patients with mucus hypersecretion. Int J Chron Obstruct Pulmon Dis 2011;6:693–9.
DOI: https://doi.org/10.2147/COPD.S22896
Goktalay T, Akdemir SE, Alpaydin AO, et al. Does high-frequency chest wall oscillation therapy have any impact on the infective exacerbations of chronic obstructive pulmonary disease? A randomized controlled single-blind study. Clin Rehabil 2013;27:710–8.
DOI: https://doi.org/10.1177/0269215513478226
Nicolini A, Grecchi B, Ferrari-Bravo M, Barlascini C. Safety and effectiveness of the high-frequency chest wall oscillation vs intrapulmonary percussive ventilation in patients with severe COPD. Int J Chron Obstruct Pulmon Dis 2018;13:617–25.
DOI: https://doi.org/10.2147/COPD.S145440
Gonçalves MR, Honrado T, Winck JC, Paiva JA. Effects of mechanical insufflation-exsufflation in preventing respiratory failure after extubation: a randomized controlled trial. Crit Care Lond Engl 2012;16:R48.
DOI: https://doi.org/10.1186/cc11249
Qiao Z, Yu J, Yu K, Zhang M. The benefit of daily sputum suction via bronchoscopy in patients of chronic obstructive pulmonary disease with ventilators: A randomized controlled trial. Medicine (Baltimore) 2018;97:e11631.
DOI: https://doi.org/10.1097/MD.0000000000011631
Fauroux B, Boulé M, Lofaso F, et al. Chest physiotherapy in cystic fibrosis: improved tolerance with nasal pressure support ventilation. Pediatrics 1999;103:E32.
DOI: https://doi.org/10.1542/peds.103.3.e32
How to Cite
Hadda, Vijay, Tejas Menon Suri, Sourabh Pahuja, Mohamad El-Khatib, Laura D. Ciobanu, Bruno Cabrita, Habib Md Reazaul Karim, et al. 2021. “Secretion Management in Patients With Ineffective Airway Clearance With Non-Invasive Mechanical Ventilation Use: Expert Guidance for Clinical Practice”. Monaldi Archives for Chest Disease 91 (4). https://doi.org/10.4081/monaldi.2021.1499.
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