Prolonged bleeding Flashcards
why is bleeding important in terms of dent ?
what are the 3 factors that if disturbed can cause a clot ?
- vessel wall
- blood flow
- clotting factors
what happens when a vessel is cut ?
- smooth muscle contraction
- posieullies law: Q = P(r^4)/L
- reduction of r of vessel by 50% causes reduction in flow of 90%
what happens after smooth muscle contraction?
platelet activation:
- aggregation (platelet plug)
- activation of clotting cascade
*happens because platelets get into contact with collagen fibres and other things outside of vessel form clot
what happens after platelet activation ?
clotting :
intrinsic pathway - collagen fibres, platelets
extrinsic pathway - tissue factors from damaged cells
final common pathway: fibrin clot
clot dissolved by plasmin
what happens if blood stagnates, turbulent flow ?
- more like Ito develop clot
what can blood stasis be due to?
- DVT = because blood clot is preventing th blood being drained from leg
can get it from = long periods of sitting and lying, long haul flights, hospital stays
how do we prevent stasis?
- stokings= tight compress muscle to prevent stasis
- clotting factors injection = enoxiparin = anticoagulant
what can disruption to vessel wall cause ?
- disruption to endothelium results in platelet activation and therefore clotting cascade
what are the problems associated with vessel wall pathology ?
- atheroma
- IHD
- CVD
- CVA
- prosthetic heart valve: recognised as foreign
how do we manage vessel wall pathology ?
- prevent activation of platelets
- aspirin
how do we manage prosthetic valve wall pathology ?
anticoagulants like warfarin or DOAC
what are the problems associated with clotting factors ?
- haemophilia A lack of factor 8
- haemophilia B lack of factor 9 = both cause lack of clotting factors lack
- von willerbrand disease (VMF expressed by loads of cells and stimulate activation of platelets ) = can’t form blood clot effectively
- liver disease = clotting factors are made in liver but don’t over estimate as liver can carry on working, they only way it can affect clotting if you are serious ill eg. little bit liver cirrhosis, fatty liver disease, alcohol disease is not serious but if they’re getting transfusions after surgery , bruising easily = then we have to consult with GP
- warfarin = designed to prevent clotting factors from being produced = stops developing clots on artificial heart valves or prevents DVT but does mean you will bleed more
- thrombocytopenia = below 100 = lack of platelets = increased bleeding risk
- apixaban, rivaroxaban = bleeding risk
how do we manage pts with inherited coagulopathy ( haemophilia, xmas disease, inherited, haemorrhagic telangiectasia)?
need to give them the specific factor theyre deficient = engage with haem team
contact gp
be guided my haematology specialists
- anticipate the risk = from MH eg. warfarin aspirin DAOC ‘s
- pre tx planning= work out when it will happen, making them aware of risk, making sure we have surgical, suturing kit, desmopressin injection, tranexamic acid, specific measures (factor transfusion)
- achieving haemostatsis
- post op plans and communication
how do we manage pts who have acquired coagulopathy? (medication, chemo, liver, kidney, warfarin, DOAC)
- if taking warfarin aspirin DOAC = refer to guidance
what is the relevance of warfarin in dental procedures ?
- can cause excessive bleeding
- need to check is stable
- if dose of warfarin has changed in last 6 months= unstable
- if INR stable should check within 72hrs
- if INR unstable check within 24hrs
- if INR is less than or equal to 4 = safe
- try not to do loads of extractions max 3
- local measures, risks pre op advice
what is the relevance of DOACs in dental procedures?
- no need to check INR
- do not stop medication before extraction
- we give pre op advice and risks and local measures
- if taking twice daily consider missing morning dose, schedule tx for morning
what is the relevance of anti platelets in dent?
- dont stop meds
- dont check bloods before hand
- we give post op instructions and local measures
what is involved in pre tx planning ?
how do we achieve haemostasis?
GDP level
- pressure = increases blood flow = triad
- oxidised cellulose gauze = vessel wall triggers platelets and CF
- suture - compresses vessels encouraging blood clot = blood flow
- time - giving CF time to work to give blood clot
specialist
- haematology input CF
- desmopressin releases WVF from platelets
- tranexamic acid - prevents activation of plasminogen breaks down clot
what instructions do we give the pt post extraction?
- giving them gauze
- contact detail office hrs and out of hours
scenario 1
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