Chronic Obstructive Pulmonary Disease (COPD) Flashcards
describe COPD
- chronic obstructive pulmonary disease
- non reversible long term deterioration in air flow through lungs due to chronic damage to airways and/or lungs
- difficulty expiring
- difficulty in ventilation makes lungs more prone to infections
what is the main cause of COPD
smoking
what triggers exacerbations of COPD in Px
triggered by infections (called infective exacerbations)
what makes COPD different from asthma
- obstruction not significantly reversible w/ bronchodilators
how might COPD present
(in a long term smoker)
- chronic SoB
- cough
- sputum production
- wheeze
- recurrent resp infections esp in winter
what symptoms or not typically seen in COPD
- doesn’t cause finger clubbing
- haemoptysis
- chest pain
give some differential diagnoses for a Px presenting w/ symptoms of COPD
- lung cancer
- fibrosis
- HF
what is the MRC (medical research council) Dyspnoea Scale
5 point scale recommended by NICE for assessing the impact of breathlessness
describe the grades in MRC Dyspnoea Scale
- Grade 1 - SoB on strenuous exercise
- Grade 2 - SoB walking up hill
- Grade 3 - SoB slows walking on flat
- Grade 4 - stop to catch breath after walking 100m on flat
- Grade 5 - unable to leave house due to SoB
what 2 things are typically used to diagnose COPD
clinical presentation and spirometry
describe the results of spirometry in COPD
- gives obstructive picture
- FEV1:FVC ratio <75%
how can severity of airflow obstruction be assessed
graded using FEV1
describe the grades of severity in airway obstruction
- Stage 1: FEV1 >80% of predicted
- Stage 2: FEV1 50-79% of predicted
- Stage 3: FEV1 30-49% of predicted
- Stage 4: FEV1 <30% of predicted
what other investigations can be done to help with diagnosis and management of COPD or to exclude other conditions
- CXR
- FBC
- BMI
- sputum culture
- ECG and echo-cg
- CT thorax
- serum alpha-1 antitrypsin
- transfer factor for carbon monoxide (TLCO)
why might FBC be done when diagnosing COPD
- to check for polycythaemia or anaemia
- polycythaemia (raised Hb) is a response to chronic hypoxia
why is serum alpha-1 antitrypsin tested for in suspected COPD
- looking for deficiency
- deficiency leads to early onset and more severe disease
why is transfer factor for carbon monoxide (TLCO) tested in suspected COPD
- decreased in COPD
- can give indication about severity of disease
- may be ^ in other conditions e.g. asthma
give an example of non pharmacological long term management of COPD
smoking cessation
what vaccines should COPD Px receive
- pneumococcal
- annual flu
outline the pharmacological long term management of COPD
STEP 1
- SABA or SAMA
STEP 2
- if no asthmatic/steroid responsive features –> combined LABA and LAMA
- if yes asthmatic/steroid responsive features –>
combined LABA and LAMA plus inhaled corticosteroid (ICS)
what pharmacological treatment options are available in more severe cases of COPD
- nebulisers
- oral theophylline
- oral mucolytic therapy
- long term prophylactic antibiotics
- long term O2 therapy at home
how might an exacerbation of COPD present
worsening of symptoms:
- cough
- SoB
- sputum production
- wheeze
describe how might exacerbation of COPD affect arterial blood gas
- acutely retaining CO2 –> carbonic acid –> blood more acidic
- low pH w/ ^ pCO2
- respiratory acidosis
describe how chronic CO2 retention in COPD can be indicated
- chronic CO2 retention indicated by ^ bicarbonate produced by kidneys to balance acidic CO2 and maintain normal pH
- in acute exacerbation, kidneys can’t keep up w/ ^ CO2 so become acidotic despite having ^ bicarb
outline how you can distinguish between the types of respiratory failure
- low pO2 indicates hypoxia and resp failure
- normal pCO2 w/ low pO2 indicates type 1 resp failure (only 1 lung affected)
- raised pCO2 w/ low pO2 indicates type 2 resp failure (2 lungs affected)
why is it important to carefully balance the amount of O2 given as O2 therapy to a COPD Px
- too much O2 can depress resp drive
- slows breathing rate and effort
- leads them to retaining more CO2
what type of mask is commonly used for O2 therapy in COPD Px
venturi mask
what is the target O2 sats for a COPD Px retaining CO2 and what mask is used to achieve this
88-92% titrated by Venturi mask
what is target O2 sats for a COPD Px that is not retaining CO2
> 94%
outline the medical treatment for an exacerbation of COPD if Px well enough to stay at home
- prednisolone 30mg once daily 7-14days
- regular inhaler or home nebuliser
- antibiotics if infection present
outline the medical treatment for an exacerbation of COPD if Px in hospital
- nebulised bronchodilators
- steroids
- antibiotics if infection present
- physiotherapy to help clear sputum
outline the medical treatment for an exacerbation of COPD in severe case where Px not responding to first line treatment
- IV aminophylline
- non invasive ventilation
- intubation and ventilation w/ admission to intensive care
- doxapram
