pulmonary embolism Flashcards
What is the difference between hypoxaemia and hypoxia?
Hypoxaemia is low levels of oxygen in the blood whereas hypoxia is in the tissues.
What is hypercapnia and who is at risk of developing it?
High levels of co2 in the blood. Sepsis patients are at risk of hypercapnia. The body increases depth of ventilation to use all available alveoli to compensate. Some copd patients also retain co2.
What are the causes of hypoxaemia?
Alveolar hypoventilation: abnormally slow or shallow ventilations. Caused by a head injury or opioids.
Diffusion impairment: something impairing the movement of gases, such as pulmonary oedema or pulmonary fibrosis.
What is ventilation/perfusion mismatch?
The difference between ventilation and perfusion in areas of the lungs. The two types are known as dead space and physiological shunt.
What is the VQ ratio?
The ventilation to perfusion ratio. V is ventilation and Q is blood. Due to gravity, the top portion of the lungs is less well perfused than the lower portions. This is the same with ventilation but to a lesser extent. There is a higher vq ratio in the apex of the lungs. Healthy vq is 0.8.
What is the AA gradient?
The difference between partial pressure of oxygen in the alveolus to the arterioles. A healthy gradient is 0 because that means the blood is well perfused.
What is a pulmonary embolism?
When a clot has formed at another site and travelled to the pulmonary circulation. Causes increased vq ratio.
What are the causes of DVT?
Deep vein thrombosis is responsible for roughly 70% of PE.
Recent surgery
fatty embolism syndrome due to trauma.
20-30% are unprovoked.
What are the causes of dvt?
immobility
varicose veins
compression of veins
endothelial injury
hypercoagulation
What are the signs and symptoms of dvt?
Localised pain in one leg
oedema, redness and heat
Homan’s test/dorsiflexion causes increased pain
