COPD
By the end of this post you will be able to:
- Confirm airflow limitation with post-bronchodilator spirometry, and distinguish the GOLD airflow grade from the ABE group that actually drives treatment.
- Initiate management of an acute exacerbation, including controlled oxygen, steroids and the decision to treat with antibiotics.
- Prescribe maintenance inhaled therapy, and recognize the adverse effects of each class.
TL;DR
What you need to know before seeing your first patient on your IM rotation with this condition
Estimated read time: 4 minutes
- What it is: Persistent, not fully reversible airflow limitation from chronic airway inflammation and alveolar destruction. Diagnosis requires post-bronchodilator FEV1/FVC <0.70.
- How it presents: Progressive exertional dyspnea, chronic cough, sputum. Exam: prolonged expiration, wheeze, hyperresonance, barrel chest, accessory muscle use.
- JAMA Rational Clinical Examination:
• Wheezing on auscultation — LR+ 36 (specificity 99.6%) but only 15% sensitive — its absence proves nothing
• Smoking >70 pack-years — LR+ 8.0
• Match test (blow out a match 10 cm away) — LR+ 7.1, LR− 0.43, the best balance of both
• Never having smoked — LR− 0.16, the strongest rule-out - Initial tests to order: In an acute exacerbation — chest radiograph (CXR), CBC, electrolytes, creatinine, ECG, nasopharyngeal swab, and an arterial blood gas (ABG) if hypoxemic or drowsy. A venous gas is a reasonable substitute if arterial sampling is not possible — it tracks pH and pCO2, though not PaO2. In a new or suspected diagnosis — post-bronchodilator spirometry, which makes the diagnosis.
- Exacerbation — the sequence: Controlled oxygen to 88–92% pending the blood gas → short-acting bronchodilators → prednisone 40 mg daily for 5 days → antibiotics only if 2 of 3 Winnipeg criteria (increased dyspnea, increased sputum volume, increased sputum purulence) → non-invasive ventilation (NIV) if the pH is <7.35 with hypercapnia.
- If unstable: drowsiness, exhaustion, a falling respiratory rate or a rising pCO2 with acidemia mean impending respiratory failure. Call your senior and involve critical care before it becomes an intubation.
Listen
Read Around the Case
Based on the CTS 2023 Guideline on Pharmacotherapy in Stable COPD, the GOLD 2025 Report, and the CTS 2025 alpha-1 antitrypsin guideline
Estimated read time: 12 minutes
1. Diagnosis and Pulmonary Function Tests
COPD is a spirometric diagnosis: a post-bronchodilator FEV1/FVC below 0.70. The bronchodilator matters — reversibility separates COPD from asthma, and testing before it misclassifies people.
The flow-volume loop is the picture worth recognizing. The expiratory limb becomes concave — scooped out — because flow collapses as the small airways close. The straight line is the predicted normal. Severity is then graded on FEV1 as a percentage of predicted: GOLD 1 ≥80%, GOLD 2 50–79%, GOLD 3 30–49%, GOLD 4 <30%.
Flow-volume curve from a patient with COPD. Evgenios Metaxas MD, CC BY-SA 3.0 via Wikimedia Commons.
The GOLD grade is not the GOLD group. The number above describes the spirometry. GOLD 2025 assigns a separate letter from symptoms and exacerbation history, and it is the letter that drives the inhaler: A — 0–1 moderate exacerbations and few symptoms (mMRC 0–1, CAT <10); B — 0–1 moderate exacerbations but more symptoms (mMRC ≥2, CAT ≥10); E — ≥2 moderate exacerbations, or ≥1 needing admission, whatever the symptom score. A patient can be GOLD 2 and group E, which is exactly the case where treating off the FEV1 alone under-treats them.
Reading the report: obstruction is the FEV1/FVC ratio. A reduced FVC with a preserved ratio suggests restriction; a low DLCO points to emphysema rather than chronic bronchitis. Volumes show air trapping — raised residual volume (RV) and total lung capacity (TLC).
Alpha-1 antitrypsin (A1AT) — test once at diagnosis
The CTS 2025 guideline conditionally recommends a one-off test in every individual with COPD at diagnosis — not only the young or never-smokers, as it is usually taught — as well as in adult-onset asthma with persistent obstruction and unexplained bronchiectasis.
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2. Acute Exacerbation
An acute exacerbation of COPD (AECOPD) is an acute worsening of symptoms beyond normal day-to-day variation, and a clinical diagnosis — there is no confirmatory test. Support gas exchange, reduce inflammation, decide about antibiotics, and find the trigger.
Exacerbation — the sequence
Target 88–92% pending an arterial blood gas
Venturi 24–28%, or nasal prongs 1–2 L/min
Short-acting beta-agonist (SABA) + anticholinergic, by nebulizer or spacer
No taper needed
Increased dyspnea · increased sputum volume · increased sputum purulence
or if ventilatory support is needed
and find the trigger — infection, non-adherence, pneumothorax, pulmonary embolism, heart failure, etc.
Antibiotics — who, and which
Treat when the Winnipeg (Anthonisen) criteria above are met, or if the patient needs ventilatory support. In McIvor’s Canadian review, patients who did not receive an antibiotic when indicated “deteriorated and required hospitalization twice as often.” Choice is then stratified by patient risk, not by how dramatic the exacerbation looks:
A rule worth carrying: if the patient has had antibiotics for any reason in the past three months, change the class rather than increasing the dose or extending the course.
On antibiotic duration: five days is enough for most exacerbations — GOLD 2025 recommends 5–7 days, and longer courses have not been shown to reduce recurrence. Review at 48–72 hours and reassess the diagnosis if there is no response, rather than extending by reflex.
On steroids: five days is enough. REDUCE (Leuppi, JAMA 2013) showed a 5-day course non-inferior to 14 for re-exacerbation, and older recommendations of 10 to 14 days predate it. No taper is needed after five days.
3. Maintenance Pharmacotherapy
The CTS 2023 guideline organizes maintenance therapy around symptom burden and exacerbation risk, not FEV1 alone. Inhaled therapy does not restore lost lung function; it reduces symptoms and prevents exacerbations, and that distinction is worth being honest with patients about.
The device matters as much as the drug
A prescription only works if the drug reaches the lung. Metered-dose inhalers need a slow, steady breath; dry-powder inhalers (DPI) need a fast, forceful one — opposite maneuvers, and patients on both frequently do one of them wrong. Watch the patient use the device rather than asking whether they know how; the Lung Association has a patient guide to inhaler technique worth handing out. Escalating therapy without watching the patient use the device treats a delivery problem with a third molecule.
There is also a climate dimension. Choosing Wisely Canada Internal Medicine recommendation 14 advises against prescribing greenhouse gas-intensive metered-dose inhalers where a lower-carbon alternative of comparable efficacy exists — a dry-powder inhaler, soft-mist inhaler or low-propellant MDI — but only where technique is adequate and patient preference has been considered. Those caveats are part of the recommendation, not a footnote: switching someone to a device they cannot use is not an environmental win.
A fuller account of inhaler adverse effects, including the ones patients notice and stop the drug over, is in this Canadian Journal of General Internal Medicine review.
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★ marks the interventions associated with a mortality benefit in COPD — smoking cessation, home oxygen in hypoxemia, pulmonary rehabilitation and vaccination. Almost nothing else in this post extends life; the inhalers reduce symptoms and exacerbations.
4. ★ Home Oxygen
Long-term oxygen therapy (LTOT) is one of the few interventions shown to prolong survival, and it is prescribed for hypoxemia, not breathlessness. Patients who are breathless but not hypoxemic do not benefit — a difficult conversation worth preparing for.
- Who qualifies: assessed when clinically stable, at least 6–8 weeks after an exacerbation and on optimal therapy — never on the numbers from an acute admission. Criteria are a resting PaO2 ≤55 mmHg (or SaO2 ≤88%), or PaO2 56–59 mmHg with cor pulmonale, right heart failure or polycythemia.
- How much: benefit depends on duration — at least 15 hours a day, including overnight. Fewer hours has not been shown to improve survival.
- Practicalities: funding and reassessment rules vary by province. Ask about smoking — home oxygen and continued smoking is a genuine fire risk — and about stairs, portability and whether the patient can manage the equipment.
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5. Prevention and Non-Pharmacologic Care
The interventions that change the natural history of COPD are mostly not drugs. This section is where the durable benefit is, and it is routinely the thinnest part of a discharge summary.
- ★ Smoking cessation is the single most effective intervention — the only one shown to slow the rate of FEV1 decline. Offer pharmacotherapy and referral at every admission, not only when the patient raises it. Relapse is expected and is not a reason to stop offering.
- ★ Vaccination. Every admission is an opportunity, and it is repeatedly missed. Influenza annually — it both triggers exacerbations and precedes bacterial superinfection. Pneumococcal: NACI (Nov 2024) recommends one dose of Pneu-C-20 or Pneu-C-21 for adults 65 and over, and for adults under 65 with risk factors, which includes chronic lung disease — so most of these patients qualify regardless of age. Add COVID-19 and RSV per current guidance. Put it on the discharge checklist.
- ★ Pulmonary rehabilitation improves exercise capacity, symptoms and quality of life, and reduces readmission after an exacerbation. Referral within a few weeks of discharge is the highest-yield moment, and it is under-used.
- Air quality, including wildfire smoke. Canadian wildfire seasons now cause widespread smoke exposure, and people with COPD are among the most affected. Counsel on checking the Air Quality Health Index, staying indoors with windows closed on heavy-smoke days, and having an action plan and enough medication on hand before the season — the Lung Health Foundation has practical guidance for patients.
- Lung cancer screening — ask who qualifies. Your COPD patients are the highest-risk group there is, and the thresholds differ across North America. USPSTF 2021: annual low-dose CT for ages 50–80 with ≥20 pack-years who smoke now or quit within 15 years. CTFPHC 2016 is narrower — ages 55–74, ≥30 pack-years, up to three annual scans, and only where there is expertise in early diagnosis and treatment. Provincial programs may use a different route again: the Ontario Lung Screening Program screens ages 55–80 with 20 years of daily smoking, then applies a risk calculator and enrols those with a ≥2% six-year risk. Check your own province’s program rather than assuming.
- Advance care planning. Severe COPD carries a mortality comparable to many cancers. Discuss goals of care while the patient is stable rather than during an admission with a rising pCO2.
Do not withhold oxygen from a hypoxemic patient for fear of CO2 retention. The fear is real but the response to it is often wrong. The answer is controlled oxygen titrated to 88–92% with a blood gas to follow — not leaving someone hypoxemic. Hypoxemia kills faster than hypercapnia, and the patient who arrives on a non-rebreather and the patient who arrives on nothing are both being managed by reflex rather than by target.
Test Yourself
Click on your answer to reveal the explanation.
A 68-year-old man with known COPD is admitted to the medical ward with three days of increased dyspnea, increased sputum volume and new sputum purulence. His blood pressure is 138/82 mmHg and has been stable, heart rate 96 beats/min, respiratory rate 24 breaths/min, and he is afebrile. SpO2 is 88% on room air. He is alert and speaking in short sentences. His chest is quiet with scattered wheeze. An arterial blood gas has been sent but is not yet back.
What is the most appropriate oxygen target?
A 71-year-old woman with COPD attends clinic for review. Her post-bronchodilator FEV1 is 45% predicted. She has had two exacerbations in the past year, one requiring admission. She takes a combined LAMA/LABA inhaler daily, and her technique is checked and correct. She remains breathless walking on the flat. Blood eosinophils are 0.35 × 109/L. She has no history of asthma. Blood pressure 126/74 mmHg, and she stopped smoking six years ago.
What is the most appropriate next step in her maintenance therapy?
Reflect
A 66-year-old man with COPD is seen in clinic. He stopped smoking eleven years ago and asks why he still has to take inhalers every day when he feels reasonably well most of the time — and whether any of it is “actually doing anything” now that he has quit. How would you answer him?
Please do not include patient identifying details — no names, initials, dates, medical record numbers, or any detail that could identify a specific patient or encounter. Write about your reasoning, not about a real person.
Further Reading
- Canadian Guideline2023 CTS Guideline on Pharmacotherapy in Patients with Stable COPD — Bourbeau et al. The Canadian anchor for maintenance therapy.
- Canadian GuidelineCTS Alpha-1 Antitrypsin Deficiency: Targeted Testing and Augmentation Therapy — Hernandez et al, Chest 2025;167:1044–1063. Recommends testing every patient with COPD at diagnosis.
- International GuidelineGOLD 2025 Report — Global standard, updated annually. Covers exacerbation management, where no current Canadian guideline exists.
- Canadian ReviewAntibiotics in Acute Exacerbations of COPD — McIvor RA, Can Fam Physician 2009;55(1):15–21. Risk-stratified antibiotic choice.
- Clinical ExamDoes the Clinical Examination Predict Airflow Limitation? — Holleman & Simel, JAMA 1995;273(4):313–319. Likelihood ratios for bedside findings.
Week 2