haem vol 1 Flashcards
what is the transfusion threshold for asymptomatic healthy patients.
what are the contraindications to transfusion
7
in coronary heart disease/ ortho ops - 8
there are no absolute contraindications other than religious.
two people should verify transfusions before beginning.
what do you have to do in preperation for blood transfusions
blood type- test recipients blood- lasts 72 hours, check for abo compatibility + any other troublesome antigens.
blood bank will hold 2 units.
transfusion should be complete within 4 hours of the blood being taken out of temperature controlled storage.
discuss transfusion reactions
multiple types -
Acute- only small amount of transfusion needed. - Autoantibodies (IgM against donor cell) - most dangerous- clerical error. - Stop + give IV fluid resus.
Febrile non-haemolytic- Rare- antibodies in pts plasma reacting to donor proteins. slower onset- fever + rigors 30-60 mins after transfusion. – anti pyretic +/- piriton.
anaphylactis- classical anaphylaxis mgt.
S+S of acute transfusion reactions
mild- inc temp 1-2 degrees
urticaria
rash
pruritus
Severe- Pyrexia, rigors, Hypotension, back/loin pain
inc anxiety
respiratory distress
dark urine
tacy
bleeding.
severe hypotension without anaphylaxis suggests ABO incompatability or bacterial contamination.
dyspnoea without shock- consider lung injury or cardiac overload.
discuss TRALI and TACO
TRALI- 1-2 hours after transfusion- fully manifested by 6 hrs.
non cardiogenic pulmonary oedema (inc vasc perm by host neutrophils reacting to substances in donor blood)
dyspnoea, hypoxia, pulm oedema, infiltrates on CXR neutropenia followed by neutrophilia
Need ICU admission–> ventilatory support. fluid challenge often helps, diuretics often worsen.
TACO—> excessive rate of transfusion on pre-exsisting heart faliure. later than trali- within 6 hours.
RAISED JVP (not in TRALI) HTN, no fever.
loop diuretic + O2, fluid will worsen.
discuss warfarin management when bleeding, when not bleeding and with changing INR
Major Bleed- stop warfarin- 5mg IV vit K. give FFP or prothrombin complex concentrate if available
INR >8 + minor bleeding. –> stop warf, IV vit K 1-3mg- repeat if still high after 24 hrs. restart warf when INR<5
INR >8 + no bleed–> stop warf, oral vit K 1-5mg. repeat if still high after 24 hrs. restart when <5
INR 5-8 + minor bleed–> stop warf, Iv vit K 1-3mg. restart then <5
INR 5-8 + no bleed–> withold 1-2 doses, decreace subsequent maintenance dose.
what are the warfarin targets for different conditions
VTE- >2.5
recurrent VTE >3.5
AF >2.5
teratogenic but can be used when breasfeeding.
how to manage bleeding associated with DOAC?
for all bleeding assoc with antocoagulation:
confirm anticoag drug + dose + time since last. + stop it.
calculate creatine clerance (weight, dose)
apply haemostatic measures (compression, packing, splinting)
urgent FBC, U&E, LEFT, INR, APTT, Thrombin, FIbrinogen, group + save.
arrange further suitable Ix
if MAJOR: IV acess, resusitation
Tranexamic acid 1g IV slow. then 1gm 8 hourly
reversal agent.
significant but non major: consider RBC + platelet, definative management.
Minor- restart if stopped
reversal agents are available- prothrombin complex concentrate (for all factor 10 inhibs) - the ban’s
idarucizumab- thrombin inhibitor reversal agent. tran’s
discuss inherited clotting diseases
haemophilia A- factor 8 deficiency - 2nd most common. X-linked- males affected
APTT prolgued. bleeding + PT normal (generally) - discovered after a procedure or injury that takes a long time to heal
Haemophilia B- deficiency in factor 9- 3rd most common.
X-linked again. - delayed healing after injuries or wounds.
Von willebrand disease-
von willenbrand factor deficiency- most common
autosomal dominant.
APTT prolongued, bleeding prolongued. PT normal.
normal duration for epistaxis is 7-10 mins.
gingivitis can be a bleeding sign.
overview of a clotting screen
PT- exteinsic pathway - 10 to 13 is normal.
INR is standardised PT.
APTT- intrinsic
TT- measures common pathway.
with all you remove the calcium initially, then add it back when testing.
discuss diseminated intravascular coagulopathy
inappropriate activation of clotting cascades–> depleted clotting factors and platelets + thrombus formation.
Causes- sepsis, trauma, malignancy, obstetric complications (HELLP syndrome, amniotic fluid embolism)
Symptoms- fever, excessive bleeding, confusion.
Signs: Thrombocytopaemia, increaced PT
raised D dimer (low fibrin- broken down), petichial bleeding,
Rx:
manage underlying condition
supportive blood product replacement.
scoring system for DIC
0 points: platelets >100. D dimer no inc, PT <3 seconds fibrinogen >1
1 point: platelets <100, d dimer moderate inc, PT 3-6 seconds. fibronigen <1g
2 points: platelets <50, strong in in d dimer, >6 PT.
if 5 or more- DIC
if less than 5 repeat every 1-2 days.
factor 5 leiden issues
most common inherited thrombotic disorder
autosomal recessive
factor 5 is resistant to inactivation by activated protein C–> means you can switch it on but never off. pro thrombotic
heterozygotes usualy fine but avoid major trauma, complicated pregnancies and ACOID COCP.
(factor 5 converts prothrombin to thrombin once activated)
prevalence 1-5% in white people.
test for it if people are exceptionally young, atypical sites, family history.
Rx is the same as any prothrombotic person.
list other cases of inherited prothrombotic disorders
Protheombin mutation
protein C + S deficiency—> can occur in pregnancy also. (S+C+thrombin= activated protein C. inhibits 8a, 5a)
antithrombin deficiency- (inhibits thrombin and activated 10a)
high factor 8 levels
hyperhomocysteinaemia– high levels of this can increace TF expression + platelet reactivity. inc thrombin and inc 5 activity
list causes of aquired thrombotic disorders
surgery, immobility, stroke, cardiac faliure, pelvic obstruction
dehydration
hyperviscocity
long flights (4+ hours)
obesity
myeloproliferative disorders
COCP
pregnancy
HRT
pick lines
heart valves
antiphospholipid syndrome.
Thrombotic Thrombocytopenic Purpura
results from a congenital or aquired reduction/ abscence of a von willenbrand factor cleaving protease (ADAMTS13)
results in microthrombi all over the body - end organ ischaemia and damage.
CNS and kidneys are the most affected.
untreated- 90% die. but with Rx only 10-15%
1-13 cases per MILLION.
presentation of Thrombotic Thrombocytopenic Purpura and treatment and some investigation + scoring.
usually after 40 years of age, but children can get it.
pentad of symptoms
fever, hemolytic anemia, thrombocytopenia, and renal and neurologic dysfunction
Rx: plasma exchange + high dose corticosteroid therapy. - once daily exchange.
if you do a blood smear and schistosites are present- PLASMIC scoring can help.
lab must show anaemia and thrombocytopenia
what is sickle cell anaemia + how does it make people sick.
substitution of Glu to Val at pstn 6.
HbS made not HbA.
carries O2 fine normally, but when deoxygenated changes shape and allows itself to distort the cell.
conditions favouring sickling- acidosis, low flow vessels
repetative sickling leads to breakdown and premature haemolysis.
loads of free Fe2= in the blood (some mopped up by haptoglobulin) - leads to 2’ haemochromocytosis —> ferratin could therefore be high!
increaced reticulocytes seen ad BM compensates (and expands- characteristic skull x-ray changes)
SC RBC can block vessels- avascular necrosis, spelic infarct +automegaly
potential triggers for sickle cell chrisis + S+S and investigations + management
none during first couple months of life- fetal hb does not have the defectiv B chain.
Cold, dehydration, infection, hypoxia
S+S- severe pain, dactylitis, mesenteric ischaemia, CNS infarcts, AVN, ulcers
IX:
labs- Hb 60-90, high reticulocites, high bili, normal MCV.
Blood smear- sickle cells + target cells
protein electrophoresis - looking fro HbS
aim to diagnose at birth
Mx:
hydroxycarbamine if frequent crisis- inc prod oh Hbf
opioids for pain
abx + immunisation to avoid splenic sequestration
blood transfusions - avoid Fe overload
rarely –> BM transplant +/- gene therapy.
in acute flare:
quick adequate analgesia
hydrate + rx trigger
VTE prophylaxis.
complications of sickle cell
stroke
vaso occlusion in hte lungs- acute chest syndrome–> viscious cycle of not allowing Hb to become oxygenated dispite deoxygenated Hb being the cause— worsened by hypoxic vasoconstriction
Rx lung with high flow 02, abx, urgent exchange transfusion.
other vasoocclusion- kidneys
penis (priaprism)
