Dyspnoea Flashcards
1
Q
What is dyspnoea?
A
Shortness of breath
2
Q
What two things can dyspnoea be due to?
A
- Hypercapnia:
- Holding onto CO2
- Respiratory acidosis
- PaCO2 normal = 40 mmHg
- Increased = hypercapnia
- Hypoxia
- There are two types of respiratory failure, both present with decreased O2
- PaO2 normal = 100 mmHg
- Hypoxia = 60 mmHg
- Sets in on the arterial side hence why we call it ABGs
3
Q
Dyspnoea Causes:
Explain pathophysiology of pulmonary causes
A
Pulmonary Problems:
- Central Chemoreceptors (CC) are more sensitive to CO2 changes
- Are located in medulla
- Arterial PCO2: 40 mmHg
- Venous PCO2: 47 mmHg
- Co2 readily crosses BBB so CC measure CSF to detect CO2
- Decreases pH (via increase in H+)
4
Q
Dyspnoea Causes:
Explain pathophysiology of cardiac problems
A
E.g. L sided HF
- Mitral Stenosis
Resulting in exudative oedema
- Rich in proteins
- Causes dyspnoea
5
Q
Dyspnoea Causes:
Explain pathophysiology of CNS problems
A
- Eg Narcotics/Opioids
- Respiratory centre depressed
- Hypoventilation
6
Q
History of Dyspnoea:
What are the two past history questions to ask for dyspnoea?
A
- Is the dyspnoea acute or chronic?
- ACUTE suggests infection or PE (DVT, rapid shallow breathing)
- CHRONIC suggests asthma/COPD, interstitial disease - Does it occur doing something in particular?
- Dyspnoea upon exertion or at rest?
- Dyspnoea lying down (orthopnoea) – CHF – increase acculation of fluid/oedema in lungs
- Dyspnoea while standing (platypnoea) – common with AVM, arterio venous malformations and hepato-pulmonary syndrome
