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Thursday, September 23, 2010

Updated Transfusion Medicine


Common Session with Assoc. Prof Naznin =)

1st Scenario
Trigger 1
45 yo lady was admitted for elective hysterectomy
Previously was pregnant for 4 times. No history of blood transfusion
Not on any medications
On admission, Hb=8g/dL
1 unit of packed red cells was ordered to correct anemia prior to surgery
Result from lab = Group 0 Rh D positive, cross matched done & compatible

Questions:
1) what did the elective operation meant to you??
Elective means the surgery was planned & patient was not bleeding. The operation can be postponed if there is no compatible blood found for the patient & the laboratory will find what is the cause of incompatibility in the blood
If written emergency operation, the blood bank need to provide compatible blood ASAP as the patient is bleeding

2) What is the significant in stating how many times the patient had delivered & any transfusion before??
Evidence of sensitization to fetal antigen @ to the previous blood transfusion

3) Issue regarding Hb level prior to surgery.
In standard practice, we take 10g/dL prior to surgery
But there was case, patient with Hb as low as 7g/dL was allowed to go for surgery, provided the CVS was good & it also depends on what type of surgery that the patient went for.

4) Is 1 unit of blood is worth to transfuse to this patient??will it make any difference between Hb 8 & Hb 9 prior to the surgery???
This issue is debatable.
One school of thought, No difference, no need to transfuse
The other one, Yes, it increase the oxygen capacity & using only 1 unit, the patient will have less exposure to the donor's blood

Trigger 2
Treatment began at 1.45pm given through standard infusion set
Upon receiving 1/2 unit, she experienced chills & had a Temperature elevation to 39.4C (pre-transfusion-37.2C)
She was anxious
Transfusion was stopped & Dr in charge was notified
Transfusion reaction investigation was initiated
No ID error

Questions:
1) What should you suspect in this patient??
Hemolytic transfusion reaction - ABO incompatibility

& need to look for:
any pain at infusion site @ localised to loins, abdomen chest pr head (related to rapid complement activation at the site of infusion & generation of bradykinin following complement activation)
hypotension, bradycardia or both
nausea/vomitting
dyspnea
flushing
dark color urine (hemoglobinuria)

2) Bear in mind, this patient develop fever, what is the commonest cause of fever in transfusion??
Febrile Non-hemolytic transfusion reaction (FNHTR)
Def: febrile episodes where there is a temperature rise of 1C or more during or soon after transfusion
Occurs with red cell transfusion & platelet transfusion

3) What is the cause of FNHTR?
reaction between recipient's HLA / granulocyte-specific abs with donor leucocytes & the subsequent release of pyrogens principally IL-1, IL-6 & TNF release from leucocytes during the 5 days storage
This is happened because the patient had been sensitised in her previous pregnancy

4) How to treat patient with FNHTR??
Stop the transfusion
Administer PCM 1g orally 1 hour before transfusion
Resume SLOW transfusion, once patient stabilised

5) In future transfusion....
Give leuco-reduced products. Provided after 2 febrile reactions have been documented
The leucocyte was filtered. Can either be done prestorage filter @ bed side filter. The best would be prestorage filter. In bed side filter, there is already cytokines in the plasma, eventhough the leucocyte was filter at bed side before transfused to the patient

2nd Scenario
38 years old male admitted to surgical department from A&E
2 unit of pack red cell ordered due to bleeding with Hb of 7g/dL
2 unit of blood was crossmatched & found compatible
Transfusion of the 1st unit was initiated following ID check & documentation of Vital signs
30 minutes after the transfusion had begun,he developed urticarial rash with itching

Questions:
1) What do you think happened to this patient?
Allergic reaction

2) How to treat the problems?
Discontinue transfusion
Administer Antihistamine
Once resolves, resume SLOW transfusion

3rd Scenario
45 years old male had bleeding from peptic ulcer
Patient was transfused 4 months earlier for similar problem
On admission, Hb was 7g/dL
4 unit of pack cell was ordered, crossmatched & transfused
On 5th day of admission, the patient was found to be febrile (39C) with pallor & jaundice
Hb = 5g/dL
2 unit of blood was ordered but found to be incompatible on crossmatching

Questions:
1) What do you think happened to the patient?
Delayed Hemolytic transfusion reaction (DHTR)
Secondary to immune response following re-exposure to a given red cell antigen in a patient who has been sensitized

Could occur within 5-7 days up to 2-3 weeks following transfusion

sensitization occurs through pregnancy (definitely not in this pt) & result of previous blood transfusion

A few days following transfusion the antibody level rises leading to destruction of the donor's red cells beginning 2 to 10 days after transfusion
(that's why initially indirect coombs test is negative - initially the antibody is too low to be detectable & results in compatible blood result)

DHTR are much milder.
Destruction of sensitized RBCs is extravascular hemolysis (the ab involve is IgG)
Generally no symptoms
If symptomatic - fever, falling hct, jaundice & rarely renal failure

2) Why patient develop jaundice?
Red cells coated with IgG antibodies which activate complement up to C3b adhere to the C3b receptor on macrophages & monocytes & are subsequently removed through extravascular destruction
Immediate extravascular destruction of red cells will cause jaundice & accompanied by hemoglobinemia & hemoglobinuria (dt antibody dependant cytotoxicity) & fever

3) Why patient was febrile (39C)?
Due to anaphylatoxins
C3a and C5a - anaphylatoxins with potent proinflammatory effects
granule enzymes release from mast cells & granulocytes
Nitric oxide production & cytokines production (IL-1, IL-8 & TNF)

4) Why Hb patient drop???
Answer:???
(Prof Naznin said its out homework.Huhu.
In the handbook mentioned, due to immediate extravascular destruction of red cells cause failure to achieve the expected rise in Hb level..is this the answer??hermmm~ )

4th Scenario
55 yo male undergo abdominal surgery due to carcinoma
Hb 10g/dL
2 units of blood was ordered
Patient blood group O Rh D positive
Crossmatched 2 units was compatible
During surgery, 1 unit was transfused following which the patient developed oozing from surgical site, BP fell from 120/70 to 80/40
Transfusion was stopped. Hypotension treated
Blood sample sent for GXM for 2 units of blood

Questions:
1) What do you think happened to this patient??
Immediate hemolytic transfusion reaction

2) Why the blood oozing from surgical site?
In anaesthesized patient, the only signs maybe uncontrollable hypotension or excessive bleeding as a result of DIVC

3) How DIVC happened?
Intravascular hemolysis stimulate extrinsic coagulant cascade & cause sonsumption of platelet which leads to DIVC

Addition:
- Main cause is human error (wrong blood component is transfused-involving transfusion of ABO incompatible blood group
- Main underlying pathophysiology for this is intravascular hemolysis
- Intravascular hemolysis is the most dangerous type of hemolytic transfusion reaction
- Associated with activation of full complement cascade by IgM abs & always due to A, B, anti A or anti-B
- Full activation to membrane attack complex on the red cell surface leads to lysis
- Sign & symptoms are severe & dramatic
- Apparent after receiving as little as 20ml & can occur within minutes - within 24hours of transfusion
- Most fatalities associated with transfusion more than 200ml & mortality approaches 44% for infusions exceeding 1000ml

Thats all about the scenarios =)
Later Prof Naznin shared with us cases that arised from transfusion medicine & I would like to share 3 lessons with you guys

Lesson 1: Check & double check the blood label & Patient's ID WITH THE PATIENT before transfused the blood to the patient. Do not only check the blood's label & ID with the transfusion form. The blood & form might be wrong & belong to someone else. Again CHECK WITH THE PATIENT.

Lesson 2: Do not ASSUME. Do not assume the label of blood & patient ID was checked by your colleagues. Check the label of blood and patient ID YOURSELF. Eventhough the blood was handed to you by your friends for transfusion for a particular patient. Please Check with the patient.

Lesson 3: Do not ASSUME. Do not assume that all the blood in the ice box belong to one patient. Check & double check the blood details before transfuse to the patient. There is no such thing as just take the blood and straightaway transfuse to the patient eventhough it is in emergency situation

Lastly, Prof gave us few OBA & MCQs. This is the summary of it

ONE
Patient develop hemolysis 2 hours after transfusion with 2 unit red cells.
Serology results:
A positive
Antibody screening negative
Direct Coombs test negative

Answer: Non-immune hemolysis (because the ab & direct coombs test were negative. Meaning the problem did not related to immune)
If ab & coombs test are positive meaning we are dealing with immune hemolysis

What can cause this??
Prior to blood transfusion usually we will give normal saline to patient. If prior to transfusion, th e patient was given D5, it will cause hemolysis to the patient.
Transfusion was given via small bore needle --> hemolysis
The blood was not in appropriate temperature or being heat prior to admission

TWO. Patient develop fever, need to sent for culture and sensitivity.
If patient develop reactions due to bacterial pyrogens or bacteria, patient will present with septic or endotoxic shock

THREE. Whole blood transfusion can cause dilutional thrombocytopenia especially in massive transfusion. But it would not occur if patient was only given 2 units of whole blood.

FOUR. Washed red cells only used in patient with PNH.

FIVE. if patient need transfusion but previously patient develop fever after transfusion. What blood should you opt for? Leuco-reduced blood components either leuco reduced platelet or red cells

SIX. If Patient is iron deficiency anemia & her Hb 9 g/dL & asymptomatic. Previously she developped mild fever after transfusion. Physician ask for you to transfuse the patient. What is your choice?? Inform the physician that there is no indication & need to transfuse this patient. Yes, there is mild anemia but patient is asymptomatic. Here,the risk of transfusion reaction is higher than correcting the anemia.

Thats all I could remember from the class. Hope it benefits =)

References:
Prof Naznin's Class
Booklet : Transfusion Medicine for IIUM medical students reviewed by Assoc Prof Naznin, Dr Norlelawati, etc.

2 comments:

  1. bagus la akak ingat semua...bgs2 sbb xsempat salin semua hari tu

    ReplyDelete
  2. hahaha..nie akak salin sungguh2 tau...if akak xletak kat sini..nnt abis sume lupe =P
    hope xde ajaran sesat kat atas nie..hehe

    ReplyDelete