COPD is a progressive life-threatening lung disease that initially presents as breathlessness with exertion, but if left untreated will develop into a serious illness. It is subdivided into chronic bronchitis and emphysema:
Smoking, air pollution and recurrent respiratory infections play a role in COPD causes. It is an extremely prevalent disease, being the fourth leading cause of death worldwide.([FOOTNOTE=World Health Organization. The top 10 causes of death. http://www.who.int/mediacentre/factsheets/fs310/en/],[ANCHOR=],[LINK=])
Patients with COPD typically present with a combination of symptoms of chronic bronchitis, emphysema, and reactive airway disease. Symptoms include the following([FOOTNOTE=Agusti A, Hurd S, Jones, P et al. FAQs about the GOLD 2011 assessment proposal of COPD: a comparative analysis of four different cohorts. European Respiratory Journal 2013; 42: 1391-1401],[ANCHOR=],[LINK=]):
Diagnosis is primarily based on clinical presentation and lung function tests. Arterial blood gas tests and pulse oximetry are useful for quickly assessing the patient's O2 status. All COPD patients are diagnosed according to the Global Initiative for Chronic Obstructive Lung Disease (GOLD). The GOLD system categorises airflow limitation in patients as follows:
The ability to detect mild to moderate COPD through physical examination can be quite poor, but physical signs are more specific and pronounced for severe disease. Severe COPD may present itself through the following symptoms:([FOOTNOTE=Siafakas NM, Vermeire P, Pride P, et al. Optimal assessment and management of chronic obstructive pulmonary disease (COPD). Eur Respir. 1995; 8, 1398–1420],[ANCHOR=],[LINK=]),([FOOTNOTE=Garcia-Pachon E & Padilla-Navas I. Frequency of Hoover’s sign in stable patients with chronic obstructive pulmonary disease. J Clin Pract. 2006; 60 (5) 514–517],[ANCHOR=],[LINK=])
In severe cases, COPD patients require hospitalisation or an emergency visit. Symptoms of confusion, lethargy, respiratory muscle fatigue, worsening hypoxemia, respiratory acidosis (pH < 7.30) and concern of respiratory failure are cause for emergency care.([FOOTNOTE=American Thoracic Society. Inpatient Management of COPD. Am J Resp Crit Care Med. 1995; 152(5):97-106.],[ANCHOR=],[LINK=]) In such cases ventilatory support and intensive care unit (ICU) admission are frequent([FOOTNOTE=Wildman MJ, Sanderson C, Groves J, Reeves BC, Ayres J, Harrison DA, et al. Predicting mortality for patients with exacerbations of COPD and Asthma in the COPD and Asthma Outcome Study (CAOS) QJM. 2009;102(6):389–399.],[ANCHOR=],[LINK=]) , ([FOOTNOTE=Global Initiative for COPD. Global Strategy for Diagnosis, Management, and Prevention of Chronic Obstructive Pulmonary Disease. 2018 Report.],[ANCHOR=],[LINK=]),([FOOTNOTE=Nascimento OA, Camelier A, Rosa FW, et al; Latin American Project for the Investigation of Obstructive Lung Disease (PLATINO) Group. Chronic obstructive pulmonary disease is underdiagnosed and undertreated in São Paulo (Brazil): results of the PLATINO study. Braz J Med Biol Res. 2007;40(7):887–895.],[ANCHOR=],[LINK=]),([FOOTNOTE=Pincelli MP, Grumann AC, Fernandes C, et al. Characteristics of COPD patients admitted to the ICU of a referral hospital for respiratory diseases in Brazil. J Bras Pneumol. 2011;37(2):217–222.],[ANCHOR=],[LINK=]),([FOOTNOTE=Ai-Ping C, Lee KH, Lim TK. In-hospital and 5-year mortality of patients treated in the ICU for acute exacerbation of COPD: a retrospective study. Chest. 2005;128(2):518–524.],[ANCHOR=],[LINK=],([FOOTNOTE=Wildman MJ, Sanderson C, Groves J, Reeves BC, Ayres J, Harrison DA, et al. Predicting mortality for patients with exacerbations of COPD and Asthma in the COPD and Asthma Outcome Study (CAOS) QJM. 2009;102(6):389–399.],[ANCHOR=],[LINK=]),([FOOTNOTE=McCauley P, Dutta D. Management of COPD patients in the intensive care unit. Crit Care Nurs Clin North Am. 2012;24(3):419-30.],[ANCHOR=],[LINK=]),([FOOTNOTE=Steer J, Gibson GJ, Bourke SC. Predicting outcomes following hospitalisation for acute exacerbations of COPD. QJM. 2010;103(11):817–829.],[ANCHOR=],[LINK=]),([FOOTNOTE=Davidson AC. Critical care management of respiratory failure resulting from COPD. Thorax. 2002;57:1079-1084.],[ANCHOR=],[LINK=]),([FOOTNOTE=Afessa B, Morales IJ, Scanlon PD, Peters SG. Prognostic factors, clinical course, and hospital outcome of patients with chronic obstructive pulmonary disease admitted to an intensive care unit for acute respiratory failure. Crit Care Med. 2002;30(7):1610–1615.],[ANCHOR=],[LINK=]),([FOOTNOTE=Seneff MG, Wagner DP, Wagner RP, et al. Hospital and 1-year survival of patients admitted to intensive care units with acute exacerbation of chronic obstructive pulmonary disease. JAMA. 1995;274(23):1852–1857.],[ANCHOR=],[LINK=]) ,16
COPD can result in hypercapnia – elevated levels of carbon dioxide in the body – necessitating oxygen therapy. But oxygen treatment can bring its own set of risk factors, with hyperoxia – elevated levels of oxygen in the body – reported in some cases.([FOOTNOTE=Sassoon CH, Hassell KT, and Mahutte, CK. Hyperoxic-induced hypercarpnia in stable COPD. Am Rev Respir Dis. 1987; 135(4):907-11.],[ANCHOR=],[LINK=]) Hypercapnia can result in impaired cognitive function.([FOOTNOTE=Icalizi RA, Gemma A, Marra C, et al. 1993. Chronic obstructive pulmonary disease. An original model of cognitive decline. Am Rev Respir Dis. 1993;148(2):418-24.],[ANCHOR=],[LINK=]) In addition, hypercapnia has been associated with a poorer prognosis in patients with COPD([FOOTNOTE=Yang H, Xiang P, Zhang E, et al. Is hypercapnia associated with poor prognosis in chronic obstructive pulmonary disease? A long-term follow-up cohort study. BMJ Open. 2015; 15(12):e008909.],[ANCHOR=],[LINK=]), and both hypercapnia and hypoxia may result in deleterious effects on the lungs.([FOOTNOTE=Vadász I, Hubmayr RD, Nin N, et al. Hypercapnia: a nonpermissive environment for the lung. Am J Respir Cell Mol Biol. 2012 Apr;46(4):417-21.],[ANCHOR=],[LINK=]),([FOOTNOTE=Mach WJ, Thimmesch AR, Pierce JT, et al. Consequences of hyperoxia and the toxicity of oxygen in the lung. Nurs Res Pract. 2011:260482],[ANCHOR=],[LINK=])
Correctly administered, noninvasive ventilation (NIV) coupled with long term oxygen therapy (LTOT) is beneficial to COPD patients with hypercapnia. Furthermore, usage of NIV or noninvasive positive pressure ventilation (NPPV) can control oxygen toxicity in COPD patients with hypercapnia.([FOOTNOTE=Alhamed MK, Aljaziri FJM, Aljunaid MA, et al. Meta-Analysis - Prevention of Oxygen Toxicity in COPD Patients with Hypercapnia. EC Microbiology. 2017;10(2):37-46.],[ANCHOR=],[LINK=])