Cyanosis Flashcards
What is cyanosis?
Bluish discolouration of the skin and mucous membranes
Why does cyanosis occur?
Due to increase in amount of deoxyhaemoglobin in RBCs
What is peripheral cyanosis?
Desaturation of blood due to regional reduction in blood flow
(Can’t deliver oxygen rich haemoglobin to peripheral tissues)
Can be congestive or ischaemic
What is central cyanosis?
Inadequate oxygenation due to increased deoxyhaemoglobin
OR
Presence of Hb derivative
Congestive cyanosis
Due to the slowing of blood flow
Ischaemic cyanosis
Vasoconstriction leads to diminished peripheral blood flow
What are the 5 causes of cyanosis
Reduced oxygen inspired
Oxygen can’t get into lungs
Oxygen can’t get into blood
Reduced systemic oxygen
Oxygen can’t bind to haemoglobin
Reasons for reduced oxygen inspired
Problem with oxygen supply
Low atmospheric pressure
Hypoventilation
BOAS
Reasons for oxygen not getting to lungs
URT obstruction
Chest damage
Muscle damage
Pneumothorax
Tracheal collapse
Pleural space disease
Reasons for oxygen not getting into the blood
Intrapulmonary shunts
Diffuse alveolar disease
Diffuse interstitial disease
Ventilation/perfusion mismatch
Reasons for reduced systemic oxygen
Anaemia
Heart disease with output failure
R to L shunting
Hypovolaemia
Extreme vasoconstriction
Sepsis
Reasons for O2 not binding to Hb
Methemoglobinemia
Carboxyhaemoglobin
Haemoglobinopathy
Significance of cyanosis
Cyanosis overrides all emergencies (except arterial bleed)
If an animal is cyanotic then the animal must be severely hypoxaemic
* May be normocapnic
Hypoxaemia
Reduced oxygen in blood
Hypoxia
Reduced oxygen in tissues
