An Overview Of Non-Invasive Ventilation In COPD Management

Chronic obstructive pulmonary disease or COPD is a common, preventable, and treatable condition characterized by persistent respiratory symptoms and airflow limitation due to structural abnormalities in the airways and alveoli. The prevalence of COPD has been consistently rising over the past several years, with an estimated 44% increase in the global burden of COPD in the past decade.
The prevalence of COPD in India has increased from 3.3% (28.1 million cases) in 1990 to 4.4% (55.3 million cases) in 2016. It is also the second most common cause of non-communicable disease-related mortality in India.1,2

Clinical Course in COPD - Chronic, Progressive With Risk of Acute Exacerbations

COPD is characterized by chronic inflammatory changes affecting the airways, lung parenchyma, and pulmonary vasculature. The chronic inflammatory response and subsequent tissue destruction lead to airflow limitation and impaired gas exchange. As the disease progresses, impairment of gas exchange leads to CO2 retention and hypoxia. Occasionally, certain triggers (bacterial or viral pneumonia, environmental irritants, etc.) can trigger an acute exacerbation characterized by an acute worsening of respiratory symptoms which can progress to acute respiratory failure.3
Significant advances in the care of COPD patients has helped reduce disease mortality, however, it has also likely resulted in them living longer with advanced COPD. This has created a need to explore therapies beyond the traditional management options like inhaled bronchodilators,
corticosteroids, pulmonary rehabilitation, etc.3

Non-Invasive Ventilation - Place in COPD Management

Non-Invasive Ventilation (NIV) refers to the administration of external ventilatory support without using an invasive artificial airway (endotracheal tube or tracheostomy tube). It may help avert some of the complications inherent with invasive ventilation, such as the need for sedation, risks of hemodynamic instability, nosocomial infection, etc. NIV consists of the delivery of positive pressure ventilation via an external interface such as facemask, nasal mask, etc.4

NIV is a promising modality to decrease work of breathing and improve respiratory mechanics in COPD patients through its beneficial effects on several pathophysiologic abnormalities seen in severe COPD.5

Non-invasive ventilation has been effectively studied in acute exacerbations of COPD and is known to confer benefits like reduced mortality, reduced need for endotracheal intubation, and decreased hospital stay. Recently, there have been studies done that demonstrated a beneficial effect of home-based NIV in stable COPD patients, outside of acute exacerbations. The inclusion of NIV as a therapy in acute or stable COPD is extensively studied in the ISCCM Guidelines and ERS Guidelines and they have laid down expert recommendations in their publications.

Use of NIV in Acute Exacerbations of COPD

The use of NIV in patients with COPD exacerbation has been well established for more than two decades.
The use of NIV during COPD exacerbations helps prevent the development of acute respiratory acidosis and the need for invasive mechanical ventilation. It is also used as a therapeutic alternative to invasive mechanical ventilation in patients with severe acidosis and respiratory distress.

The Indian Society of Critical Medicine (ISCCM) recommends the use of NIV in the following situations pertaining to COPD6

Key Highlights of ISCCM 2020 Guidelines6 

● NIV should be used in the management of acute exacerbation of COPD in patients with acute or acute-on-chronic respiratory acidosis (pH = 7.25-7.35)
● NIV should be attempted in patients with acute exacerbation of COPD (pH <7.25 & PaCO2 ≥ 45) before initiating invasive mechanical ventilation, except in patients requiring immediate intubation
● NIV should not be used routinely in normo- or mildly hypercapnic patients with acute exacerbation of COPD, without acidosis (pH > 7.35)

Long-Term Home NIV for Management of Stable COPD

Non-invasive ventilation is increasingly being used as a long-term treatment in COPD patients with hypercapnic chronic respiratory failure, however, there exists a paucity of clinical evidence supporting the benefits of long-term home NIV in such cases. The European Respiratory Society (ERS) task force have developed evidence-based guidelines on the application of long term home NIV (LTH-NIV) for patients with hypercapnic COPD having chronic respiratory failure.

COPD remains a leading cause of hospital admissions and mortality in spite of multi-modality treatments with pharmacotherapy, pulmonary rehabilitation, supplemental oxygen, lifestyle interventions, etc. The use of NIV in the acute setting, as well as a long-term home-based modality, seems to be a promising approach to reduce untoward disease outcomes.

References:

1. The burden of chronic respiratory diseases and their heterogeneity across the states of India: the GlobalBurden of Disease Study 1990-2016. India State-Level Disease Burden Initiative CRD Collaborators.Lancet Glob Health. 2018 Dec; 6(12):e1363-e1374.
2. Gudi N, Mahmood A, Roy MP, Ravishankar, Nayak P, Verma A. Burden of COPD among population above 30 years in India: protocol for a systematic review and proposed meta-analysis. Can J Respir Ther.2021 Feb 1;57:14-17.
3. Agarwal AK, Raja A, Brown BD. Chronic Obstructive Pulmonary Disease. [Updated 2021 Sep 7]. In:StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2021 Jan-. Available from:https://www.ncbi.nlm.nih.gov/books/NBK559281/
4. Popat B, Jones AT. Invasive and non-invasive mechanical ventilation. Medicine (Abingdon). 2012Jun;40(6):298-304
5. Coleman JM 3rd, Wolfe LF, Kalhan R. Noninvasive Ventilation in Chronic Obstructive PulmonaryDisease. Ann Am Thorac Soc. 2019 Sep;16(9):1091-1098
6. Chawla R, Dixit SB, Zirpe KG, Chaudhry D, Khilnani GC, Mehta Y, et al. ISCCM Guidelines for the Use of Noninvasive Ventilation in Acute Respiratory Failure in Adult ICUs-. Indian J Crit Care Med 2020;24(Suppl 1):S00–S00.
7. Ergan B, Oczkowski S, Rochwerg B, Carlucci A, Chatwin M, Clini E, Elliott M, Gonzalez-Bermejo J, Hart N, Lujan M, Nasilowski J, Nava S, Pepin JL, Pisani L, Storre JH, Wijkstra P, Tonia T,  Boyd J, Scala R, Windisch W. European Respiratory Society guidelines on long-term home non-invasive ventilation for management of COPD. Eur Respir J. 2019 Sep 28;54(3):1901003.

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