9. COPD Flashcards
COPD
A common, preventable & treatable disease that is characterised by persistent respiratory symptoms & airflow limitation that is due to airway and/or alveolar abnormalities usually caused by significant exposure to noxious particles/gases
COPD pathophysiology - Emphysema & Chronic Bronchitis
Emphysema is a result of destroyed air sac walls, therefore the airway & its sacs lose their flexibility, making it harder for them to contract & expand
- Symptoms include wheezing, shortness of breath & chest tightness
Chronic bronchitis is the result of damaged airway liming being inflamed & producing mucus, thereby leading to the development of a persistent cough
- Symptoms include ongoing cough that produces a lot of mucus
COPD in Maori
- Burden greater in Maori than other New Zealanders
- Onset 15-20 years younger
- Hospitilisation 3.5 times higher
- Mortality 2.2 times higher
Bronchitis - areas affected & pathophysiology
Bronchiole - smallest airway that lead to alveoli, purpose is to deliver air to the alveoli
Smooth muscle - responsible for controlling airway calibre
Mucus - Known as airway surface liquid, is a thin layer of fluid covering the luminal surface of the airway to protect the lung through mucociliary clearance of foreign particles & chemicals
Inflammation -> smooth muscle contraction -> mucus hyper secretion
Emphysema - areas affected
Alveoli - tiny air sacs that are primary location of gas exchange
Elastic fibres - allow alveoli to expand & recoil back
Loss of elastic fibres -> decreased surface area -> collapsed alveoli
Diagnosing COPD
Risk factors:
- Host factors
- Tobacco
- Occupation
- Indoor/outdoor pollution
Symptoms:
- Shortness of breath
- Chronic cough
- Sputum
Spirometry:
- Required to establish diagnosis
Spirometry & its key measures
Common test to assess lung function
Key measures include:
Forced expiratory volume (FEV1)
- Amount of air that can be forced from the lungs in 1 second
Forced vital capacity:
- Largest amount of air that can be forcefully exhumed in 1 breath
FEV1/FVC ratio:
- Calculated value that represents the percentage of your lung capacity you can expel in 1 breath
Role of spirometry
Diagnosis
Assessment of severity of airflow obstruction (for prognosis)
Follow up assessment:
- Therapeutic decisions + Pharmacological in selected circumstances e.g. discrepancy between spirometry & level of symptoms
+ Consider alternative diagnoses when symptoms are disproportionate to degree of airflow obstruction
+ Non-pharmacological (e.g. interventional procedures)
- Identification of rapid decline
Assessment - Goals
To determine the levels of airflow limitation & its impact on the patient’s health status
To achieve these goals, consider:
- Presence & severity of spirometric abnormality
- Current nature & magnitude of the patient’s symptoms
- History of moderate & severe exacerbations & future risk
- Presence of co-morbidities
Note: There is only a weak correlation between FEV1 symptoms & impairment of a patient’s health status - formal symptomatic assessment required
Classification of airflow limitation severity in COPD (based on post-bronchodilator FEV1)
In patients with FEV1/FVC < 0.70:
GOLD 1: Mild - FEV1 ≥ 80% predicted
GOLD 2: Moderate - 50% ≤ FEV1 < 80% predicted
GOLD 3: Severe - 30% ≤ FEV1 < 50% predicted
GOLD 4: Very severe - FEV1 < 30% predicted
Modified MRC dyspnea scale & CAT score
mMRC - grade 1 to 4 regarding patients breathlessness
CAT - questionnaire regarding what the patient thinks about their condition & severity of it
Refined ABCD assessment tool
Takes into account all aspects of COPD
Spirometry: FEV1/FVC < 0.7
Assessment of airflow limitation: GOLD 1-4
Assessment of symptoms/risk of exacerbations
- 0 or 1 (not leading to hospital admission) [A or B]
- ≥2 or ≥1 leafing to hospital admission [C or D]
- mMRC 0-1, CAT <10 [A or C]
- mMRC ≥2 CAT ≥10 [B or D]
COPD exacerbations
- Defined as an acute worsening of respiratory symptoms that result in additional therapy
- Best predictor of having frequent exacerbations (≥2 exacerbations per year) is a history of earlier events
- Deterioration in airflow limitation is associated with an increasing prevalence of exacerbations, hospitalisations & death
Remember treat holistically - co-morbidities/risk factors
- Smoking
- Poor diet - adequate nutrition required
- Cardiovascular disease - comorbidity
- Metabolic syndrome - gas exchange
NZ COPD guidelines 2021 - severity
Mild:
- Few symptoms
- Breathlessness on moderate exertion
- Little or no effect on daily activities
- Cough & sputum production
- FEV1 typically 60-80% predicted
Moderate:
- Breathlessness walking on level ground
- Increased limitation of daily activities
- Recurrent chest infections
- Exacerbations requiring oral corticosteroids and/or antibiotics
- FEV1 typically 40-59% predicted
Severe:
- Breathless on minimal exertion
- Daily activities severly restricted
- Exacerbations of increasing frequency & severity
- FEV1 typically < 40% predicted
NZ COPD guidelines 2021 - Medicine management
CHECK device technique & adherence at each visit
Step 1: START with a SABA for PRN use e.g. salbutamol, terbutaline, ipratropium or combination salbutamol + irpatropium
Step 2: ADD a LAMA e..g tiotropium, glycopyrronium or umeclidinium, or a LABA, e.g. salmeterol,, indacaterol or formoterol as an alternative
Step 2A: Consider the need for a combination LABA/LAMA e.g. indacaterol/glycopyrronoum, vilanterol/umeclidinium, olodaterol/tiotropium depending on patients symptoms. Patients with an eosinophilic pattern of disease may benefit from ICS/LABA instead of LAMA/LAMA
Step 3: CONSIDER adding an ICS e.g. fluticasone or budesonide: Triple therapy may be appropriate for patients with ≥ 1 exacerbation requiring hospitalisation or ≥ 2 moderate exacerbations in the last 12 months, AND signifiant symptoms despite LABA/LAMA or ICS/LABA treatment. Patients with a blood eosinophil count ≥ 0.3 x 10^9/L are most likely to benefit from ICS treatment
Treatment goals
Reduce symptoms:
- Relieve symptoms
- Increase exercise tolerance
- Improve health status
Reduce risk:
- Prevent disease progression
- Prevent & treat exacerbations
- Reduce mortality
Smoking cessation
Greatest benefit in COPD
- Nicotine replacement therapy
- Varenicline
- Bupropion
- Nortriptyline
Vaccinations
Influenza vaccine:
- Reduces serious illness & death in COPD patients
- Should be actively promoted
- Subsidised in NZ for those with COPD
Pneumococcal vaccine:
- Recommend for all patients ≥ 65 years or younger patients with significant comorbidities to reduce the incidence of pneumonia & reduce exacerbations
- Evidence conflicting & not subsidised in NZ for those with COPD
Bronchodilators
- Inhaled bronchodilators are central to symptom management
- Regular & as-needed use of SABA & SAMA improves FEV1 & symptoms
- Combination SABA + SAMA are superior to either alone
- LABAs & LAMAs significantly improve lung function, shortness of breath, health status & reduce exacerbation rates
- LAMAs reduce exacerbations & decrease hospitalisations greater than LABAs
- Combination LABA + LAMA reduce exacerbations compared to either alone
Bronchodilators cont’d
LABAs & LAMAs are preferred over short-acting agents except in those with only occasional shortness of breath & when immediate relief of symptoms required
- Patients may be started on single long-acting bronchodilator or dual-long acting bronchodilator therapy (under SA)
- If a single long-acting bronchodilator is ineffective in reducing symptoms of shortness of breath add another of a different class
Pharmacological treatment groups
Group A: Bronchodilator
Group B: Long acting bronchodilator (LABA or LAMA)
Group C: LAMA
Group D: LAMA or LAMA + LABA or ICS + LABA
Antimuscarinic drugs
- Block the bronchoconstrictor effects of acetylcholine on M3 muscarinic receptors expressed in airway smooth muscle
- Very safe as poorly absorbed when given via inhaled route however watch for dry mouth, urinary symptoms, bitter or metallic taste
Inhaled corticosteroids
Regular ICS increases the risk of pneumonia especially in those with severe disease
Key messages about drugs in COPD
- Inhaler technique, device suitability & adherence should be reviewed regularly
- SABA +/- SAMA for symptom relief
- LAMA bronchodilator class of choice
- Escalate to LABA + LAMA combination if LAMA does not control breathlessness/exacerbations
- ICS to reduce exacerbations in addition to LABA + LAMA combination ‘triple therapy’
- ICS + LABA if raised eosinophils or asthma/COPD overlap
Inhaled route
- Choice of inhaler device should be individually tailored & take into account the patient’s ability to use the device & their preference
- Inhaler techniques should be demonstrated when starting on the device & regularly while patients are on therapy
Soft mist inhalers
“Turn, Open, Press”
Pros:
- Very fine mist particles
- Excellent lung deposition
- Once daily dosing
- Little medication deposited into the oropharynx
Cons:
- Requires good coordination & dexterity to use
- Requires loading of device
- Must be able to hold breath to ensure dose it not exhaled
Breezehaler & Handihaler
Requires capsule to be inserted into device & contents inhaled
Pros:
- Can inhale multiple times to receive dose
- Breezhaler capsules clear so can visibly check if dose is completely inhaled
Cons:
- Capsule should not be swallowed
- Good dexterity required to load & manipulate capsules & device
Ellipta devices
Flip open cover, revealing the mouthpiece until it click
Pros:
- Easy to use
- Large font dose indicator
Cons:
- Can cause cough & taste disturbances
Other anti-inflammatories
- Long term use of oral glucocorticoids (prednisone) are not recommended due tp numerous side effects & lack of benefit however beneficial in exacerbations
- Antibiotics (macrolides e.g. azithromycin/erythromycin) reduce exacerbation rate over a year
Pulmonary rehabilitation
- Education & exercise programme to help patients’ self-management of their chronic breathing problems to make behavioural changes improving symptom control & their quality of life
- Programme often up to 8 weeks
- Multidisciplinary team approach
- May reduce readmissions & mortality rate
Surgical options
- Lung volume reduction surgery
- Bullectomy
- Transplantation
- Bronchoscopic interventions such as end-bronchial valves, lung coils, vapour ablation
End stage COPD
- Opiates (e.g. Morphine)
- Oxygen in those with resting hypoxia
- Nutritional supplementation in malnourished
- Ventilation in those with hypercapnia
