COPD Flashcards
define
chronic progressive lung disease characterised by airflow obstruction with the following:
- chronic bronchitis
- emphysema
Airway obstruction: FEV1 <80%, FEV1:FVC <0.70
Chronic bronchitis: cough and sputum production on most days for 3mo of 2 successive years.
Emphysema: histological diagnosis of enlarged air spaces distal to terminal bronchioles c¯ destruction of alveolar walls
epidemiology
10-20% of over 40s
causes
- Smoking!
- Alpha-1 antitrypsin deficiency
Other causes
- cadmium (used in smelting)
- coal
- cotton
- cement
- grain
s/s
symptoms
- cough + sputum
- dyspnoea
- wheeze
- wt loss
signs
- tachypnoea
- prolonged expiratory wheeze
- hyperinflation [decreased cricosternal distance, loss of cardiac dullness, displaced liver edge]
- wheeze
- may have early inspo crackles
- cyanosis
- cor pulmonale: high JVP, oedema, loud P2
- signs of steroid use
pink puffer: define, features, ix
seen in emPhysema
- Pink puffers have a good respiratory drive.
- in alveolar ventilation thus: breathless but not cyanosed
- normal or near normal pa02
- normal or low pac02
- progresses to T1 resp failure
Features include:
- purse-lip breathing with intense dyspnoea
- patient is often thin and elderly
- little sputum produced
- oedema and overt heart failure are rare complications
Investigations:
- blood gases are near normal until pre-terminally
- there is very severe airways obstruction
- total lung capacity is increased
- reduction in transfer factor
blue bloaters
in chronic Bronchitis
- Blue bloaters have a poor respiratory drive.
- low alveolar ventilation thus cyanosed but not breathless
- low pa02 and high pac02= rely on hypoxic drive
- progresses to= T2 resp failure + cor pulmonale
Features include:
- dyspnoea is quite mild
- the patient is often obese
- large volumes of sputum are produced
- infective exacerbations
- patient often oedematous
- may develop cor pulmonale
Investigations:
- blood gases - hypercapnia, hypoxaemia, elevated plasma bicarbonate, severe nocturnal hypoxaemia
- airways obstruction may only be moderate
- transfer factor approximately normal
diagnosis
NICE recommend considering a diagnosis of COPD in patients over 35 years of age who are smokers or ex-smokers and have symptoms such as exertional breathlessness, chronic cough or regular sputum production.
The following investigations are recommended in patients with suspected COPD:
- post-bronchodilator spirometry to demonstrate airflow obstruction: FEV1/FVC ratio less than 70%
- chest x-ray: hyperinflation, bullae, flat hemidiaphragm. Also important to exclude lung cancer
- full blood count: exclude secondary polycythaemia. alpha1antitrypsin levels
- body mass index (BMI) calculation
how is severity of copd categorized
The severity of COPD is categorised using the FEV1*:
~~~~~
Measuring peak expiratory flow is of limited value in COPD, as it may underestimate the degree of airflow obstruction.
*note that the grading system has changed following the 2010 NICE guidelines. If the FEV1 is greater than 80% predicted but the post-bronchodilator FEV1/FVC is < 0.7 then this is classified as Stage 1 - mild
**symptoms should be present to diagnose COPD in these patients
stable COPD mx
General management
- smoking cessation advice
- annual influenza vaccination
- one-off pneumococcal vaccination
Bronchodilator therapy
a short-acting beta2-agonist (SABA) or short-acting muscarinic antagonist (SAMA) is first-line treatment
for patients who remain breathless or have exacerbations despite using short-acting bronchodilators the next step is determined by the FEV1
FEV1 > 50%
- long-acting beta2-agonist (LABA), for example salmeterol, or:
- long-acting muscarinic antagonist (LAMA), for example tiotropium
FEV1 < 50%
LABA + inhaled corticosteroid (ICS) in a combination inhaler, or:
LAMA
For patients with persistent exacerbations or breathlessness
- if taking a LABA then switch to a LABA + ICS combination inhaler
- otherwise give a LAMA and a LABA + ICS combination inhaler
Oral theophylline
- NICE only recommends theophylline after trials of short and long-acting bronchodilators or to people who cannot used inhaled therapy
- the dose should be reduced if macrolide or fluoroquinolone antibiotics are co-prescribed
Mucolytics
should be ‘considered’ in patients with a chronic productive cough and continued if symptoms improve
Cor pulmonale
- features include peripheral oedema, raised jugular venous pressure, systolic parasternal heave, loud P2
- use a loop diuretic for oedema, consider long-term oxygen therapy
- ACE-inhibitors, calcium channel blockers and alpha blockers are not recommended by NICE
Factors which may improve survival in patients with stable COPD
- smoking cessation - the single most important intervention in patients who are still smoking
- long term oxygen therapy in patients who fit criteria
- lung volume reduction surgery in selected patients
COPD acute exacerbations presentation
Exacerbations of COPD are associated with increased:
- dyspnoea
- sputum purulence
- volume of sputum
hx of:
- smoking status
- exercise capacity
- prev rx
- prev exacerbations
COPD: management of acute exacerbations
The most common bacterial organisms that cause infective exacerbations of COPD are:
- Haemophilus influenzae (most common cause)
- Streptococcus pneumoniae
- Moraxella catarrhalis
Respiratory viruses account for around 30% of exacerbations, with the human rhinovirus being the most important pathogen.
NICE guidelines from 2010 recommend the following:
- increase frequency of bronchodilator use [salbutamol/impratropium] and consider giving via a nebuliser [+ air driven through nasal specs]
- give prednisolone 30 mg daily for 7-14 days
- it is common practice for all patients with an exacerbation of COPD to receive antibiotics. NICE do not support this approach. They recommend giving oral antibiotics ‘if sputum is purulent or there are clinical signs of pneumonia’
Various factors are considered when deciding whether the patient should be managed in the community or in the hospita
factors which favour treatment in hospital
- not able to cope at home
- severe beathlessness
- general condition is poor/ deteriorating
- level of activity is poor/confined to bed
- cyanosis is present
- worsening peripheral oedema
- impaired level of consciousness
- patients is already receiving long term oxygen therapy
- patient is living alone/ not coping
- acute confusion is present
- exacerbation has had a rapid rate of onset
- there is significant comorbidity particularly cardiac disease and insulin-dependent diabetes)
- SaO2 < 90%
- changes on the chest radiograph are present
- arterial pH level < 7.35
- arterial PaO2 < 7 kPa
non invasive ventilation
Non-invasive ventilation - key indications
- COPD with respiratory acidosis pH 7.25-7.35*
- type II respiratory failure secondary to chest wall deformity, neuromuscular disease or obstructive sleep apnoea
- cardiogenic pulmonary oedema unresponsive to CPAP
- weaning from tracheal intubation
Recommended initial settings for bi-level pressure support in COPD
- Expiratory Positive Airway Pressure (EPAP): 4-5 cm H2O
- Inspiratory Positive Airway Pressure (IPAP): RCP advocate 10 cm H20 whilst BTS suggest 12-15 cm H2O
- back up rate: 15 breaths/min
- back up inspiration:expiration ratio: 1:3
*the BTS guidelines state that NIV can be used in patients who are more acidotic (i.e. pH < 7.25) but that a greater degree of monitoring is required (e.g. HDU) and a lower threshold for intubation and ventilation should be used
If hospital treatment is indicated then what ix would you do
investigations include:
- echest X-ray
- arterial blood gases (record inspired oxygen concentration)
- ECG
- blood tests
- Full blood count and urea and electrolytes
- Theophylline level if patient on theophylline at admission
- Sputum microscopy and culture if purulent
- further management
- give oxygen to keep SaO2 above 90%
- assess need for non-invasive ventilation:
- consider respiratory stimulant non-invasive ventilation not available
- assess need for intubation
- if poor response to nebulised bronchodilators then consider intravenous theophyllines
- Once stable then consider for hospital-at-home or assisted-discharge scheme.
- Before the patient is discharged then establish on optimal therapy and, if necessary, arrange multidisciplinary assessment.
COPD: long-term oxygen therapy
The 2010 NICE guidelines on COPD clearly define which patients should be assessed for and offered long-term oxygen therapy (LTOT). Patients who receive LTOT should breathe supplementary oxygen for at least 15 hours a day. Oxygen concentrators are used to provide a fixed supply for LTOT.
Assess patients if any of the following:
- very severe airflow obstruction (FEV1 < 30% predicted). Assessment should be ‘considered’ for patients with severe airflow obstruction (FEV1 30-49% predicted)
- cyanosis
- polycythaemia
- peripheral oedema
- raised jugular venous pressure
- oxygen saturations less than or equal to 92% on room air
Assessment is done by measuring arterial blood gases on 2 occasions at least 3 weeks apart in patients with stable COPD on optimal management.
Offer LTOT to patients with a pO2 of < 7.3 kPa or to those with a pO2 of 7.3 - 8 kPa and one of the following:
- secondary polycythaemia
- nocturnal hypoxaemia
- peripheral oedema
- pulmonary hypertension
ddx of acute exacerbation of copd
pneumothorax
pulm oedema
PE
asthma- exacerbation
pneumonia- consolidation on cxr
LVF
drug induced decrease in resp function[review meds for sedation/bb]
