Management of haemorrhage in OS Flashcards
(34 cards)
What is primary haemorrhage?
Bleeding at the time of surgery - blood stained saliva 12-24 hours post surgery
What is reactionary haemorrhage?
Bleeding usually occurs 2-3 hours post XLA as the LA vasoconstrictor wears off - call 111
What is secondary haemorrhage?
Up to 14 days after the surgery - most likely cause of this is infection
What are the stages of blood clotting?
Vasoconstriction - vascular spasm in smooth muscle in the walls of blood vessels
Platelet plug formation - adhesion, interaction and aggregations of platelets
Coagulation cascade - clotting factors in the extrinsic, intrinsic and common pathways leading to the formation of fibrin
What is fibrinolysis?
Occurs when plasma enzyme plasminogen activates plasmin which digests the fibrin threads in the clot
Where are the majority of clotting factors produced?
Liver
Where are the platelets produced?
Red bone marrow
Where do the intrinsic and extrinsic clotting factor pathways converge?
Clotting factor X
What happens after the clotting pathways converge?
Factor V plus Ca convert prothrombin to thrombin which intern, converts fibrinogen to fibrin (network which stabilises a clot alongside platelets in a plug)
What clotting factor deficiencies can cause post operative bleeds?
Haemophilia A - factor 8
Haemophilia B - Factor 9
vWF disease - affects platelet adhesion and causes factor 8 deficiencies
Vit K deficiencies - factor 2, 7, 9 and 10
What acquired liver diseases can cause clotting issues?
Hepatitis/cirrhosis
History of alcohol XS
Which thrombocytopenic diseases cause clotting issues?
Immune idiopathic thrombocytopenia ITP
Secondary disease - to leukaemia
Drug induced antiplatelet therapy
Which vascular anomolies can cause post op bleeds?
Arterio-venous malformations
Hereditary haemorrhagic telangiectasia
Collagen disorders
How to treat pts with haemophilia?
X linked disorder
Factor replacement
Fresh frozen plasma
Replacement factors and proteins
How to treat vWF sufferers?
vWF - protein required for platelet aggregation
Protects factor 8 from rapid breakdown
Factor 8 deficiencies requiring replacement
Which complications arise from having cirrhosis and hepatitis?
Varices which can lead to bleeds and anaemia
What are the causes of thrombocytopenia?
150-400 x 10^9/L
Drug induced, e.g. NSAIDs/ alcohol, heparin
Aplastic anaemia
Immune driven (idiopathic)
EBV/HIV
How to manage patients on vit K antagonists
Warfarin, acencoumarol, phenindione
Check INR no more than 24 hours before procedure (up to 72hrs if patient is stably coagulated)
If INR is below 4 - treat without interruption of meds
Stage Tx
Consider suture and packing
If above 4 - delay tx and refer
How does warfarin work?
Inhibits vit k dependant synthesis of biologically active forms of the clotting factors 1,8,9 and 10 as well as the regulatory factor proteins
Blocking enzyme called vit k epoxide reductase
How does aspirin work? (acetylsalicylic acid)
NSAID which suppresses platelet fn by blocking formation of thromboxane A2 in platelets producing an inhibitory affect on platelet aggregation during the 8-9 day lifespan of platelet.
Also inhibitors COX 1 and COX 2 which reduce the production of proinflammatory prostaglandins
What local measure should be taken in aspirin alone users?
Pack and suture
Stage tx
Extensive or complex procedures
How does clopidogrel work?
antiplatelet meds that reduce risk of MI and stroke
Can be prescribed with aspirin - dual antiplatelet therapy following coronary stent placement
Irreversibly inhibits adenosine diphosphate (ADP) receptor which is important for platelet activation and cross linking of fibrin
Which other medications work similarly to clopidogrel?
Ticagrelor and prasugrel
How do DOACs work?
Dabigatrin
Reversibly bind to active site on thrombin preventing thrombin mediated activation of coagulation factors and may enhance fibrinolysis
