Respiratory Medicine

A diagnosis of COPD should be considered in any patient who has dyspnea, chronic cough, and/or sputum production and an appropriate history of exposure to noxious stimuli. However, not all patients with these symptoms have COPD, and a spirometry demonstrating a post-bronchodilator forced expiratory volume in one second to forced vital capacity (FEV1/FVC) ratio < 70% (or less than the lower limit of normal, if available) is required to make a definitive diagnosis. Starting maintenance inhalers without first objectively diagnosing COPD results in unnecessary treatment in those patients who do not actually have the disease. In turn, this exposes these patients to both the side-effects and the cost of these medications, and might delay the appropriate diagnosis.

Sources:

Global Initiative for Chronic Obstructive Lung Disease (GOLD). GOLD 2019 Global Strategy for the Diagnosis, Management and Prevention of COPD [Internet]. 2019.

Qaseem A, et al. Diagnosis and management of stable chronic obstructive pulmonary disease: a clinical practice guideline update from the American College of Physicians, American College of Chest Physicians, American Thoracic Society, and European Respiratory Society. Ann Intern Med. 2011 Aug 2;155(3):179-91. PMID: 21810710.

United States of America Department of Veterans Affairs and the Department of Defense. VA/DoD Clinical Practice Guideline for the Management of Chronic Obstructive Pulmonary Disease [Internet]. 2014 Dec [cited 2017 May 5].

Lung cancer screening with a chest CT scan has no proven benefit in patients who are not at high risk for lung cancer. The use of low dose chest CT scan for lung cancer screening has been found to reduce lung cancer mortality in patients at high risk for lung cancer. While there are some differences across jurisdictions in terms of the eligibility for enrollment in a screening program, the Canadian Task Force on Preventive Health Care currently recommends screening adults aged 55-74 years old with a 30 pack-year smoking history who currently smoke or quit less than 15 years ago, though some screening programs are using evidence-based risk assessment calculators to determine eligibility for enrollment. However, screening is also associated with several potential harms, including false-negative and false-positive results, incidental findings, overdiagnosis (detecting indolent and clinically insignificant tumors that would not have been detected in the patient’s lifetime without screening), and cumulative exposure to radiation (which can cause cancer). Screening also leads to unnecessary anxiety and invasive procedures, which carry their own complications. Accordingly, it should not be used in patients who do not meet these evidence-based criteria, nor in patients with a health problem that substantially limits life expectancy or the ability or willingness to have curative therapy. Because of the evolving nature of the evidence for lung cancer screening eligibility criteria, and the need to ensure access to all the necessary components of high-quality screening, it is recommended that lung cancer screening occur within an organized screening program when it is available within a reasonable geographic proximity and a reasonable wait time.

Sources:

Canadian Task Force on Preventive Health Care, et al. Recommendations on screening for lung cancer. CMAJ. 2016 Apr 5;188(6):425-32. PMID: 26952527.

Krist AH et al. Screening for Lung Cancer: US Preventive Services Task Force Recommendation Statement. JAMA. 2021;325(10):962-970. doi:10.1001/jama.2021.1117. PMID: 33687470.

National Lung Screening Trial Research Team, et al. Reduced lung-cancer mortality with low-dose computed tomographic screening. N Engl J Med. 2011 Aug 4;365(5):395-409. PMID: 21714641.

O’Dowd EL, Baldwin DRBach PB, et al. Lung cancer screening-low dose CT for lung cancer screening: recent trial results and next steps. Br J Radiol. 2018 Oct;91(1090):20170460. PMID: 28749712.

Patz EF Jr, et al. Overdiagnosis in low-dose computed tomography screening for lung cancer. JAMA Intern Med. 2014 Feb 1;174(2):269-74. PMID: 24322569.

Mazzone P, et al. Components necessary for high-quality lung cancer screening: American College of Chest Physicians and American Thoracic Society Policy Statement. Chest. 2015 Feb;147(2):295-303. doi: 10.1378/chest.14-2500. PMID: 25356819.

Tammemägi MC, et al. Selection criteria for lung-cancer screening. N Engl J Med. 2013;368(8):728. PMID: 23425165.

De Koning HJ, et al. Reduced Lung-Cancer Mortality with Volume CT Screening in a Randomized Trial. N Engl J Med. 2020;382:503-513. PMID: 31995683.

Toumazis I, et al. Cost-effectiveness Evaluation of the 2021 US Preventive Services Task Force Recommendation for Lung Cancer Screening. JAMA Oncol. 2021;7(12):1833-1842. PMID: 34673885.

The majority of adults with chest pain and/or dyspnea do not have a pulmonary embolism (PE). There is strong evidence that in patients with low pre-test probability as determined by a clinical prediction rule (e.g., Wells score), a negative highly sensitive D-dimer assay effectively excludes clinically important PE. Furthermore, there are potential harms to performing CT pulmonary angiography (CTPA) or ventilation-perfusion (V/Q) scanning, including exposure to ionizing radiation, adverse events due to the administration of intravenous contrast, and identification of clinically insignificant PE leading to inappropriate anticoagulation. However, physicians should exercise clinical judgement in populations in whom this two-step algorithm has not been validated (e.g., pregnant patients).

Sources:

Borohovitz A, Weinberg MD, Weinberg I. Pulmonary embolism: Care standards in 2018. Prog Cardiovasc Dis. 2018 Mar – Apr;60(6):613-621. PMID: 29291427.

Crawford F, et al. D-dimer test for excluding the diagnosis of pulmonary embolism. Cochrane Database Syst Rev. 2016 Aug 5;(8):CD010864. PMID: 27494075.

Fesmire FM, et al. Critical issues in the evaluation and management of adult patients presenting to the emergency department with suspected pulmonary embolism. Ann Emerg Med. 2011 Jun;57(6):628-652.e75. PMID: 21621092.

Torbicki A, et al. Guidelines on the diagnosis and management of acute pulmonary embolism: the Task Force for the Diagnosis and Management of Acute Pulmonary Embolism of the European Society of Cardiology (ESC). Eur Heart J. 2008 Sep;29(18):2276-315. PMID: 18757870.

van der Hulle T, Cheung WY, Kooij S, et al. Simplified diagnostic management of suspected pulmonary embolism (the YEARS study): a prospective, multicentre, cohort study. Lancet. 2017; 390: 289– 97. PMID: 28549662.

Wiener RS, et al. Time trends in pulmonary embolism in the United States: evidence of overdiagnosis. Arch Intern Med. 2011 May 9;171(9):831-7. PMID: 21555660.

The majority of adults with a short duration of cough from an acute respiratory tract infection have a viral rather than a bacterial infection. Patients often underestimate the typical cough duration from an infectious illness, and when cough does not resolve within their expected time frame, may request antibiotics. The average duration of cough (not treated with antibiotics) is around 18 days, though patients only expect to cough for 5 to 7 days. Use of immediate or delayed antibiotics does not change clinical outcomes compared to no antibiotics in these situations. On the other hand, the harms of over-prescribing antibiotics include medication costs, adverse reactions, and the possibility of inducing bacterial resistance to antibiotics. Physicians should educate patients about the expected duration of cough and the consequences of inappropriate antibiotic use in acute respiratory tract infections.

Sources:

Ebell MH, et al. How long does a cough last? Comparing patients’ expectations with data from a systematic review of the literature. Ann Fam Med. 2013 Jan-Feb;11(1):5-13. PMID: 23319500.

Little, P, Stuart, B, Smith, S, et al. Antibiotic prescription strategies and adverse outcome for uncomplicated lower respiratory tract infections: prospective cough complication cohort (3C) study. BMJ 2017; 357. PMID: 28533265.

McNulty CA, et al. Expectations for consultations and antibiotics for respiratory tract infection in primary care: the RTI clinical iceberg. Br J Gen Pract. 2013 Jul;63(612):e429-36. PMID: 23834879.

Smith SM, et al. Antibiotics for acute bronchitis. Cochrane Database Syst Rev. 2014 Mar 1;(3):CD000245. PMID: 24585130.

Snow V, et al. Principles of appropriate antibiotic use for treatment of acute bronchitis in adults. Ann Intern Med. 2001 Mar 20;134(6):518-20. PMID: 11255531.

Spurling GKP, Del Mar CB, Dooley L, et al. Delayed antibiotic prescriptions for respiratory infections. Cochrane Database Syst Rev. 2017;9. PMID: 28881007.

Although international guidelines uniformly recommend objective testing to establish an asthma diagnosis, this diagnosis is often made clinically and asthma medications are often initiated on that clinical basis. However, physical exam findings and symptoms such as cough, wheeze, and/or dyspnea can be caused by other conditions. As a result, up to one third of patients who have been diagnosed with asthma do not have evidence of asthma when objectively tested with pulmonary function tests. A false clinical diagnosis of asthma may delay diagnosis of the actual underlying condition, which may include serious cardiorespiratory conditions. Furthermore, patients with a false diagnosis of asthma who are started on asthma medications are unnecessarily exposed to both the side-effects and the costs of these medications.

For individuals 6 years of age and older who are able to reliably perform pulmonary function testing, an abnormal spirometry (or challenge test) can be helpful for confirming a diagnosis of asthma, however spirometry can also be falsely negative, especially in individuals with episodic symptoms.  Objective testing for asthma is not broadly available for children less than 6 years old and, in this age group, the diagnosis of asthma should be made clinically.

Following the global pandemic, availability of diagnostic testing is limited in many regions, and treatment can be initiated without confirmatory testing when diagnostic testing is not available in a timely manner. Individuals should be clinically reassessed, and the diagnosis should be confirmed with pulmonary function testing as soon as such testing is available. Consideration should strongly be given to stopping asthma therapy if the individual has not had a severe exacerbation in the last year, testing fails to confirm the diagnosis, and/or clear benefit is not observed. Where safe and possible, individuals should stop asthma controller therapy for 4-8 weeks to optimize the sensitivity of lung function testing for asthma diagnosis.  It is noted that measurement of lung volumes and diffusing capacity (DLCO) are not needed for a diagnosis of asthma.

Sources:

Aaron SD, et al. Reevaluation of Diagnosis in Adults With Physician-Diagnosed Asthma. JAMA. 2017 Jan 17;317(3):269-279. PMID: 28114551.

British Thoracic Society/Scottish Intercollegiate Guidelines Network. BTS/SIGN British guideline on the management of asthma [Internet]. 2017 Apr [cited 2017 May 5].

Coates AL, Wanger J, Cockcroft DW, Culver BH, Diamant Z, Gauvreau G, et al. ERS technical standard on bronchial challenge testing: general considerations and performance of methacholine challenge tests. Eur Respir J. 2017;49(5). PMID: 28461290.

Devani P, Lo DKH, Gaillard EA. Practical approaches to the diagnosis of asthma in school-age children. Expert Review of Respiratory Medicine. 2021; 16(9): 973-981. PMID: 36125212.

Global Initiative for Asthma. 2017 GINA Report, Global Strategy for Asthma Management and Prevention [Internet]. 2017 [cited 2017 May 5].

Lougheed MD, et al. Canadian Thoracic Society 2012 guideline update: diagnosis and management of asthma in preschoolers, children and adults. Can Respir J. 2012 Mar-Apr; 19(2): 127–164.

Yang CL, et al.  2021 Canadian Thoracic Society Guideline – A focused update on the management of very mild and mild asthma. 2021.

Asthma exacerbations are characterized by decreased expiratory airflow as well as increased shortness of breath, cough, wheezing, chest tightness, or a combination of these symptoms. When such an attack is precipitated by an infection, it is much more likely to be viral than bacterial. The role of bacterial infection is often overestimated; however antibiotics should be reserved for relatively rare cases in which there is strong evidence of a bacterial infection, such as pneumonia or bacterial sinusitis. Potential harms of unnecessary antibiotic treatment include medication costs, side-effects (including a risk of allergy), and emergence of bacterial resistance.

Sources:

Aldington S, et al. Asthma exacerbations. 5: assessment and management of severe asthma in adults in hospital. Thorax. 2007 May;62(5):447-58. PMID: 17468458.

Bousquet J, et al. Uniform definition of asthma severity, control, and exacerbations: document presented for the World Health Organization Consultation on Severe Asthma. J Allergy Clin Immunol. 2010 Nov;126(5):926-38. PMID: 20926125.

British Thoracic Society / Scottish Intercollegiate Guidelines Network. BTS/SIGN British guideline on the management of asthma [Internet]. 2016 Sept.

Chung KF, et al. International ERS/ATS guidelines on definition, evaluation and treatment of severe asthma. Eur Respir J. 2014 Feb;43(2):343-73. PMID: 24337046.

Schatz M, et al. Joint task force report: supplemental recommendations for the management and follow-up of asthma exacerbations. Introduction. J Allergy Clin Immunol. 2009 Aug;124(2 Suppl):S1-4. PMID: 19647130.

Supporting patients with serious or progressive respiratory illness to identify and document their values and treatment wishes is an important, but often neglected, intervention. While these patients often experience complex disease trajectories that make accurate prognostication challenging, these discussions can ensure future care is aligned with patients’ preferences.

Sources:

Abbott D, et al. Men with Duchenne muscular dystrophy and end of life planning. Neuromuscul Disord. 2017 Jan;27(1):38-44. Epub 2016 Sep 28. PMID: 27816330.

Amin R, et al. Pediatric home mechanical ventilation: A Canadian Thoracic Society clinical practice guideline executive summary. Can J Respir Crit Care Sleep Med 2017; 1:7-36

Jabbarian LJ, et al. Advance care planning for patients with chronic respiratory diseases: a systematic review of preferences and practices. Thorax. 2018 Mar;73(3):222-230.  PMID: 29109233.

Shoesmith C, et al. Canadian best practice recommendations for the management of amyotrophic lateral sclerosis. CMAJ 2020; 192(46): E1453-1468. PMID: 33199452.

Tavares N, et al. The preferences of patients with chronic obstructive pulmonary disease are to discuss their palliative care plans with family respiratory clinicians, but to delay conversations until their conditions deteriorates: a study guided by interpretative phenomenological analysis. Pall Med. 2020 Dec;34(10):1361-1373. PMID: 32720555.

Metered-dose inhalers (MDIs) contain HFC propellants, which contribute to global warming. When prescribing inhalers, providers should consider whether an objective diagnosis of asthma and/or COPD exists or needs to be confirmed, in keeping with existing CWC CTS recommendations (#1 and #5). Also, optimal choice of controller inhaler agents and non-pharmacologic strategies (e.g. education, trigger avoidance, action plans) should always be included in airway disease management, as they not only improve patient outcomes, but can also reduce rescue inhaler use.

Low carbon footprint inhalers may not be appropriate for some patients (i.e. preschool children, individuals with certain cognitive limitations, end-stage lung disease, muscle weakness or other physical limitations, and during respiratory emergencies). Other patients simply prefer MDIs. Ultimately, whether starting or substituting an inhaler, providers must consider medication efficacy, patient preference, adherence, technique, cost, and side-effect profile. A shared decision-making approach should be used, and the environmental benefits of alternatives to greenhouse gas-intensive MDIs should also inform this decision.

Sources:

Gupta, S, Couillard S, Digby G, Tse SM, Green S, Aceron R, Carlsten C, Hubick J, Penz E. Canadian Thoracic Society Position Statement on Climate Change and Choice of Inhalers for Patients with Respiratory Disease. Canadian Journal of Respiratory, Critical Care, and Sleep Medicine. 2023. doi:10.1080/24745332.2023.2254283.

Canadian Thoracic Society. Respiratory Medicine: Seven Tests and Treatments to Question. Choosing Wisely Canada, last updated December 2022. Available at: https://choosingwiselycanada.org/recommendation/respiratory-medicine/

Yang C, Hicks EA, Mitchell P, Reisman J, Podgers D, Hayward KM, et al. Canadian Thoracic Society 2021 Guideline update: Diagnosis and management of asthma in preschoolers, children and adults. Canadian Journal of Respiratory, Critical Care, and Sleep Medicine. 2021;5(6):348-61. doi:10.1080/24745332.2021.1945887.

Keeley D, Scullion JE, Usmani OS. Minimising the environmental impact of inhaled therapies: problems with policy on low carbon inhalers. Eur Respir J. 2020;55:2000048. PMID: 32461340.