Approach to bleeding patient

Question 1

Define primary haemostasis

Answer 1

Primary haemostasis - initial vasoconstriction to slow blood flow and haemorrhage. Slower blood flow also enables activated platelets and clotting factors build up locally into higher conc. endothelial damage leads to platelet adherence to subendothelium. Platelet adhesion and aggregation occur to form the primary haemostatic plug, this is not very stable, but occurs in seconds to minutes, and is temporary. The coagulation cascade is also activated to produce a much more permanent solution.

Question 2

Define secondary haemostasis

Answer 2

Secondary haemostasis - the action of the coagulation factors that result in fibrin formation and a stable fibrin clot.

Question 3

Define fibrinolysis

Question 4

Draw the traditional coagulation cascade and list the diagnostic tests used to evaluate secondary haemostasis

Question 5

Relate abnormalities of tests of secondary haemostasis to the coagulation cascade

Question 6

Outline the diagnostic approach to the bleeding patient and disorders of primary and secondary haemostasis

Answer 6

ABC +MBS + STabilisise
If there is haemorrhage from anyehwere ask yourself is there normal or abnormal coagulation? Document that it is normal if so.
Then PCV/TS/CBC and blood smear before talking to the owner for a history

History
History of previous bleeding?
Eruption of permanent teeth
Oestrus
Routing surgeries
Venipuncture and vascular access
Trauma
Recent overt haemorrhage? Can they quantify it? Drops? Coin sized pools? Bigger pools? Drip drip or continuous?
Any lamenes? (covert haemorrhage into muscles or joints?)
Dyspnoea? (respiratory haemorrhage)
Is the animal actually sick now? Appetite, drinking, eating, sicker patient = more likely to have hidden nasties or serious haemorrhage
Any previous illness, medications or vaccinations that could have sparked a coagulopathy?
Any parents or littermates with history of coagulopathy?

Full PE
Might see hypoperfusion if the bleed had been of sufficient magnitude to cause hypovolaemia.
External haemorrhage - epistaxis, gingival bleeding, haematemesis, haemoptysis, haematuria, haematochezia, melaenia or bleeding from a cutaneous wound.
Chronic anaemia -> might see pale mm but normal or fast CRT, tall narrow pulses , mild tachycardia and possibly a heart murmur and v slight increase in resp rate.
Could have organ dysfunction due to bleeding or concurrent disease
Mass lesions (the underlying cancer or haematoma)
DIagnostic tests
PCV/TS/CBC (DONT stick the jugular until you know platelet count is normal!)
If your pcv/ts are normal you can be sure the animal has not had a serious bleed.
Acute bleed - perfusion status? Initially PCV and TS normal, then TS will fall before the PCV due to splenic contraction
PCV 42 TS 52 suggests acute haemorrhage
If animal has normal perfusion but is anaemic then this tells you it has to be chronic.
If TS is low as well as PCV then haemorrhage is high on the list
If TS normal, then low pCV due to lack of production or increased destruction or a slow, chronic external bleed like low grade GI haemorrhage (cant maintain pcv but can maintain TS)
If anaemic, check for signs of regeneration and morphological rbc abnormalities for a cause
Blood smear (platelet count, RBC morphology)
ACT or PT/aPTT
If clotting tests are normal consider a BMBT
Chem screen for organ assessment
Imaging to look for haemorrhage, masses and other disease

Question 7

Assess the indications for blood component therapy

Question 8

List the clinically important blood types in dogs and cats

Question 9

Define and differentiate blood typing and cross matching and their respective roles in transfusion therapy

Question 10

List the possible adverse reactions to blood component therapy and describe their clinical signs