COPD Flashcards
COPD : definition
umbrella term encompassing chronic bronchitis and emphysema
COPD : Clinical features
- Smoker : main cause is smoking
- Chronic cough
- Exertion breathlessness
- Regular sputum production
COPD : Diagnosis
- Post-bronchodilator spirometry to demonstrate airflow obstruction: FEV1/FVC ratio less than 70%, no improvement post bronchodilator
- Chest x-ray- hyperinflation, bullae, flat hemidiaphragm. Also important to exclude lung cancer
- Full blood count: exclude secondary polycythaemia
- Body mass index (BMI) calculation
COPD : Severity staging
The severity can be graded using the forced expiratory volume in 1 second (FEV1):
Stage 1 (mild): FEV1 more than 80% of predicted
Stage 2 (moderate): FEV1 50-79% of predicted
Stage 3 (severe): FEV1 30-49% of predicted
Stage 4 (very severe): FEV1 less than 30% of predicted
COPD : Management of Stable COPD : First line
- SABA
or
- SAMA
COPD : Management of Stable COPD : Second line
Assess for asthmatic features;
1. Previous diagnosis of asthma or atopy
1. Variation in FEV1 of more than 400mls
1. Diurnal variability in peak flow of more than 20%
1. Raised blood eosinophil count
COPD : Management of Stable COPD : Second line
- ? Asthmatic features are present : Prev asthma dx / variation in FEV1} likely to be steroid response
i) *LAMA + ICS
Fostair, Symbicort and Seretide are examples of LABA and ICS combination inhalers. - No Asthmatic features
* LABA + LAMA
Anoro Ellipta, Ultibro Breezhaler and DuaKlir Genuair are examples of LABA and LAMA combination inhalers.
COPD : Management of Stable COPD : Third line
combination of a
LABA + LAMA + ICS
Combination inhalers : rimbow, Trelegy Ellipta
COPD : Medical therapies (4)
- Oral theophylline
- Oral prophylactic antibiotic therapy of Azithromycin
- Mucolytics
- Phosphodiesterase - 4 inhibitors e.g. Roflumilast
COPD : Frequent exacerbations
home supply of corticosteroids and antibiotics
COPD : Medical therapies : Prophylactic antibiotics
Azithromycin
Indications: patients who; are on optimised treatment but _continue to have exacerbations_ and are not smoking.
Prior to starting;
*CT Thorax- to exclude bronchiectasis
*Sputum culture- to exclude atypical infections and tuberculosis
*ECG -to r/o Q-T prolongation as Azithromycin can cause this
*LFTs- Azithromycin can be hepatotoxic
COPD : Medical therapies : Phosphodiesterase - 4 inhibitors
Roflumilast
* MOA : Reduces the risk of COPD exacerbations in patients with severe COPD and history of frequent exacerbations
- Indication : FEV1<50% and 2> exacerbations in past year whilst on triple maximum therapy
COPD : LTOT : Indication
Offer LTOT if ABG shows any of the following
- PO2 < 7.3 kPa at room air
OR
- Pa O2 7.3 - 8.0
+
One of the following;
* Pulmonary hypertension
* Secondary polycythemia
* Peripheral oedema
(Ie - signs of chronic hypoxia or cor-pulmonale causing HF)
COPD : LTOT : Assessment
- 2 or more ABGs at least 3 weeks apart
COPD exacerbation : most common causative organism
- Haemophilius influenza - /Most common/
COPD exacerbation : Primary care management
- Increase frequency of bronchodilator use
- Steroid : 30mg prednisolone daily for 5 days
- Antibiotics :
* Amoxicillin 500mg TDS for 5 days
* Doxycyline 200mg Day 1 and 100mg OD for 5 days
COPD exacerbation : Mx of acute exacerbation
-
Oxygen therapy before ABG
* Aim for 88 - 92 % due to high risk of hypercapnia in COPD
* Via 28% Venturi mask at 4L/min -
Nebulised Bronchodilators
* Nebulised Salbutamol - provides bronchodilator affect
* Nebulised Ipratropium (SAMA) - provides anticholinergic effect -
Steroid therapy
* IV Hydrocortisone or PO Prednisolone
COPD exacerbation : Respiratory acidosis pathophysiology
- Severe bronchoconstriction secondary to exacerbation impairs the ability of the lungs to exhale CO2
- CO2 diffuses into the blood and makes it acidic
- Retention of CO2 also impairs gas exchange leading to hypoxia
COPD exacerbation : Respiratory acidosis : clinical features
- Shortness of breath and Tachycardia
- Chest pain
- Confusion and Drowsiness: elevated CO2 levels impact brain function leading to cognitive impairment
- Muscle weakness and lethargy
- Cyanosis
COPD exacerbation : Respiratory acidosis : Management
If patient develops respiratory acidosis -
pH 7.25 - 7.35
} COPD patients require NIV
NIV : Definition
mechanical ventilation to a patient’s lungs through a mask without an ‘invasive’ tube (intubation)
NIV : Indication
Used to improve oxygenation and ventilation in patients with acute or chronic respiratory failure.
NIV : iPAP/ePAP definition
- iPAP - inspiratory positive airway pressure when air is forced into the lungs
- EPAP - expiratory positive airway pressure - pressure during expiration to prevent airway collapse and increase end tidal volume
NIV : Contraindication
- Facial deformity or airway obstruction - prevents effective mask seal for ventilation
- Inadequate sedation or altered mental status- inability to tolerate mask
- Risk of aspiration or vomiting - NIV increases risk of aspiration and development of pneumonia
- Hypotension- worsens existing hypotension by reducing cardiac output
- Pneumothorox -High air pressure can worsen pleural damage and exacerbate a pneumothorax
CPAP : Definition
- Continous and constant pressure during both stages of the breathing cycle
- Provides the same pressure during inhalation and exhalation
- Continous pressure primarily - helps to keep the airways open and patent
CPAP : Indication
Improve Hypoxaemia
* Sleep apnea which involves airway obstruction during sleep
* Congestive cardiac failure
* Acute Pulmonary oedema
BiPAP : Definition
- Delivers two distinct pressures during the breathing cycle
- Higher pressure is used for inhalation - overcomes airway resistance, improves oxygenation
- Lower pressure is used for exhalation - aids to exhale CO2
BiPAP : Indication
- Respiratory acidosis ; pH 7.35 or paCO2 >6 despite adequate treatment
- COPD
- Variable breathing patterns such as those with neuromuscular diseases or central sleep apnea.
