General Flashcards
Name some obstructive conditions
- COPD
- asthma
- bronchiectasis
- bronchitis
Name some restrictive conditions
- Pneumoconiosis
- Pulmonary fibrosis
- ARDS
- sarcoidosis
What are the clinical differences between restrictive and obstructive pulmonary conditions?
Obstructive
- Reduced FVC (<80% of normal)
- Reduced FEV1:FVC ratio (<70%)
- Reduced peak flow rate
Restrictive
- Reduced FVC
- Reduced FEV1
- Normal FEV1:FVC ratio
- Normal peak flow rate
What values are given on an ABG?
- pH
- PO2
- PCO2
- HCO3
- SO2
What are the normal values for each parameter on the ABG?
What does
a) PaO2 is <10 kPa on air
b) PaO2 is <8 kPa on air
mean clinically?
a) hypoxaemia
b) severe hypoxaemia & in resp. failure
- which type? –> look at CO2
- Type 1 respiratory failure = severe hypoxaemia + hypo/normocapnaeia
- Type 2 respiratory failure = severe hypoxaemia + hypercapnaeia
Describe the distinction between type 1 and type 2 respiratory failure
i.e. in type 1, the lung’s ability to compensate for hypercapnia is preserved, but not in type 2
Type 1 respiratory failure involves
- hypoxaemia (PaO2 <8 kPa)
- normocapnia (PaCO2 <6.0 kPa).
Type 2 respiratory failure involves
- hypoxaemia (PaO2 <8 kPa)
- hypercapnia (PaCO2 >6.0 kPa).
What abnormality is shown?
a) Metabolic Alkalosis
b) Type 1 Respiratory Failure
c) Type 2 Respiratory Failure
d) Respiratory Alkalosis
e) Metabolic Acidosis
C: Type 2 Respiratory Failure
In this case we find her CO2 is raised, indicating her lungs are failing to blow it off. This mixes with water to form carbonic acid and dissociates into ions. The added hydrogen ions into the system increase the arterial pH and cause the acidosis. This is not a metabolic, but a respiratory problem.
Why is PaCO2 not raised in Type 1 Respiratory failure?
Respiratory compensation
this allows hyperventilation –> blowing off excess CO2 via other sections of lung (as focal damaged area is ‘underperforming’)
Name some acute causes of Type 1 resp. failure
- Acute asthma
- Collapse of alveolar spaces (e.g. Atalectasis, Pneumothorax)
- Fluid filling of alveolar spaces (e.g Pulmonary Oedema)
- Diffusion problem (oxygen cannot enter the capillaries due to parenchymal disease, e.g. Pneumonia, ARDS)
- Ventilation-perfusion mismatch (parts of the lung receive oxygen but not enough blood to absorb it (e.g. PE)
Name some acute causes of Type 2 resp. failure
- Acute severe asthma
- COPD
- Upper airway obstruction
- Neuropathies (GBS, MND)
- Drugs (opiates)
What sound will be heard on percussion:
- pleural effusion
- consolidation e.g. pneumonia
- Pneumothorax
- pleural effusion = stony dull
- consolidation e.g. pneumonia = dull
- Pneumothorax = hyperresonant
O/E how can you differentiate between pleural effusion and pneumonia?
- both = percussion: dullness
BUT
- pleural effusion = vocal fremitus: decreased
- pneumonia = vocal fremitus: increased
What can be heard on ausculation:
- Normal lung
- Consolidation
- Pneumothorax
- Effusion
- Normal lung = Vesicular
- Consolidation = Bronchial (liquid –> better sound)
- Pneumothorax = Diminished
- Effusion = Diminished
How can pleural effusions be categorised?
Transudates: protein<30gL
Exudates: protein>30gL