Bl.therapy2012

BLOOD THERAPY

BYMOHAMED E. ABDEL-GHAFFAR, MD.

Professor & Chairman,Department of Anesthesia &

Intensive Care, FOM, Suez Canal University.

HISTORICAL REVIEW

• Initial attempts by Lower and Denys to affect

transfusion from one animal to another led

eventually to transfusions from animals to

humans with catastrophic results leading to

legal sanctions against the practice for about

two centuries.

• In 1818 Blundell and others used humans as

both donors and recipients with occasional

though unpredictable success.

HISTORICAL REVIEW• The real breakthrough was the discovery of

human ABO blood groups by Karl

Landsteiner in 1900.

• Later Landsteiner and Levine discovered M,

N, & P groups.

• Further work by Landsteiner and Wiemer

discovered the Rhesus groups in 1939.

• In spite of all this, lack of a safe anticoagulant

remained a major transfusion problem until

1943 when Loutit and Mollison developed an

acid citrate soln.(ACD) to be mixed with

blood.

Blood groups

• 85% of the population have the D antigen and

designated Rh +ve.

• Other minor and rare blood groups include M, N, P and S

groups and they are cold agglutinins i.e. giving strong

reactions at about 20 C with little or no reactivity at 37 C.

Group Antigen on

RBCs

Antibodies

in serum

% of

population

O None Anti A, Anti

B

47

A

A Anti B 42

B

B Anti A 8

AB

A & B None 3

BLOOD THERAPY, Cont.

Compatibility testing

• The ABO - Rh type, cross match and antibody screen

were designed to demonstrate harmful antigen -

antibody interactions in vitro, so that harmful in vivo

interactions could be prevented.

Blood storage

• Banked blood contains CDP-A ( citrate, dextrose,

phosphate and adenine ) and is stored at 4-6 C to

prevent bacterial growth. This blood is valid to be

used for up to 35 days.

BLOOD THERAPY, Cont.

Indications for whole blood transfusion

• Blood transfusions are given to increase O2

carrying capacity and intravascular volume (IVV),

thus tissue hypoxia & Hb < 7 g/dl or Hct < 21 are

the only two absolute indications for whole blood.

• Additional factors that must be considered are:

• Age of the patient

• Cause of anemia & chronicity of anemia

• Hemodynamic status and presence of coexisting

cardiac, pulmonary or vascular disease.

BLOOD COMPONENT THERAPY

1- Packed Red Blood Cells ( PRBCs )

• PRBCs are made by removing 2/3 of plasma from

a unit of whole blood. Plasma removed is utilized

for other component therapy.

• PRBCs are used to restore O2 carrying capacity.

• One unit of PRBCs Hct 3 units.

BLOOD COMPONENT THERAPY Cont.

2- Fresh Frozen Plasma ( FFP )• FFP is formed when the plasma portion is removed from a

unit of whole blood and then frozen.

• FFP contains factor V, factor VIII, and prothrombin as well

as antithrombin III, protein C and protein S.

• FFP is indicated for :

1- Treatment of dilutional coagulopathy in a massively

transfused patient.

2- Correction of warfarin anticoagulation ( one unit of FFP ↓

PT by 2 sec. ).

3- Treatment of congenital or acquired coagulation factor

deficiencies.

4- Treatment of antithrombin III deficiency.

BLOOD COMPONENT THERAPY Cont.

3- Cryoprecipitate (CP )

• CP is formed when the plasma is rapidly frozen, then

allowed to rewarm.

• CP contains most of factor VIII and fibrinogen of the

original unit of blood. CP also contains factor IX,

factor VIIIa and Von Willebrand’s factor

• CP is indicated for:

1- Hemophilia A

2- Von Willebrand’s disease.

3- Hypofibrinogemic states.

4- Bleeding from thrombolytic therapy.

COMPLICATIONS OF BLOOD THERAPY

• It is always stressed that every Blood Transfusion (BT)

carries an element of risk and never be given without a

definite indication.

1- Mortality :

• Mortality as a result of BT is about 0.1 - 1.0 % and

is to be comparable with that of appendectomy.

• 3000 persons die annually in USA due to BT.

COMPLICATIONS OF BLOOD THERAPY Cont.

2- TRANSFUSION REACTIONS :A- Hemolytic transfusion reaction ( HTR ) :

• Incidence is 1/4000 to 1/6000 . The incidence of a fatal HTR is 1/100,000 .

• Mechanism : two mechanisms are recognized.

1- The most catastrophic with a mortality of 20 -60% is intravascular hemolysis when there is a direct attack on transfused donner cells by recipient antibodies and complement and usually results from ABO blood group incompatibility.

2- Extravascular hemolytic reaction is usually less serious than the iv variety.

Here recipient antibodies coats but don’t immediately hemolyse the transfused RBCs.

Destruction occurs primarily in the reticuloendothelial system ( RES ).


SIGNS AND SYMPTOMS :

Chills, fever, chest and flank pain,

nausea, flushing, hypotension,

dyspnea, hemoglobinuria, oliguria or

anuria, and increased bleeding from

the surgical field.

The clinical presentation is quite

variable


TREATMENT :

1 - STOP transfusion and return unused blood to blood

bank for recrossmatch.

2- Enforce forced alkaline diuresis to a minimum urine

output of 75 - 100 ml/hr by:

a- Generous iv fluids + Mannitol 0.5 - 1.0 g/kg over 10 -

15 min., if not enough give iv furesemide 20 - 40 mg.

b- Alkalinize urine : 0.5 -1.0 mEq/kg NaHCO3 is usually

sufficient to raise urine pH to 8. High urine pH ensures

rapid clearance of hemoglobin

3- Assay urine & blood Hb conc, platelet count, PTT and

serum fibrinogen levels .

4- Send patient blood to blood bank for antibody screen 5-

Prevent hypotension to ensure adequate renal blood

flow.

COMPLICATIONS OF BLOOD THERAPY Cont.B- Delayed hemolytic transfusion reaction :

• In many cases of HTRs, the transfused donner cells may

survive well initially, but after a variable delay ( 2 - 21 days )

will be hemolysed.

• This reaction is common in people who had received

multiple blood transfusions and in females who had

multiple pregnancies.

• In this type of reaction the antibody level at the time of

transfusion is too low to be detected or too low to cause

RBC destruction.

• RBCs destruction occurs only when the level of antibody is

increased after a secondary immune response ( anamnestic

response ).

• These reactions are usually manifested by a decrease in the

post-transfusion Hct.

• Unlike the immediate reactions Rh and Kidd system rather

than ABO system are implicated.

COMPLICATIONS OF BLOOD THERAPY Cont.C- Non hemolytic transfusion reactions :

• These reactions are usually not serious and are of either

febrile or allergenic nature.

• Most allergic reactions are anaphylactoid and are caused

by the presence of foreign protein in the transfused blood.

• The most common symptoms are urticaria and itching ,

some patients develop facial swelling, chills, fever,

headache, nausea and myalgia.

• Incidence is around 3% and they usually respond to H-1

blockers.

• Infrequently a more severe form of allergic reaction

involving anaphylaxis occurs and causes dyspnea, chest

pain and shock.

• This type of reaction does not involve RBCs destruction

and occurs rapidly after transfusion of few mls of blood or

plasma. Adrenaline must be given SC, IM or IV.


3- Transmission of disease :

1- Hepatitis A, B and C

2- HIV.

3- Human T Cell Leukemia Virus type-1 ( HTLV-1 ).

4- Cytomegalovirus ( CMV ).

5- Syphilis and malaria.

6- Others are much less common e.g., Herpes,

infectious mononucleosis, toxoplasmosis,

brucellosis, trypanosomiasis, leishmaniasis,

salmonillosis, typhus and filariasis.


4- Citrate intoxication :

• Stored blood contains citrate as an

anticoagulant and if transfused rapidly at

a rate > 70 ml/kg/min. may lead to S&S of

citrate intoxication which are essentially

those of hypocalcemia, since citrate binds

Ca thus decreasing serum Ca leading to

tremors, hypotension and cardiac

arrhythmias.

• Citrate is rapidly metabolized by the liver

to HCO3 .


5- Dangers of cold blood :

• Transfusion of unwarmed stored

blood at 4 C can lower the recipient

temp. markedly leading to shivering,

ventricular arrhythmias or even

sudden arrest.

• Proper warming of blood using

thermostatically controlled devices is

a good and safe practice.


6- Changes in O2 transport :

• The respiratory function of RBCs may impaired during

preservation, making it difficult for stored RBCs to

release O2 to tissues immediately after transfusion.

O2 dissociation curve of stored blood is shifted to

the left.

• This may be manifest for 24 hr following BT.

7- Coagulation abnormalities :

• More pronounced after massive BT and include:

1- Dilutional thrombocytopnea.

2- Low factors V and VIII.

3- Disseminated Intravascular Coagulation ( DIC ).


8- Circulatory overload :• Neonates, elderly and patients with limited cardiac reserve

are more likely to suffer.

• HR, BP and CVP are increased. Lung bases may show

crepitations.

9- Infusion of microaggregates :• It has been demonstrated that amounts of clot and debris in

bank blood increases with duration of storage, and some of

this particulate matter is not filtered by the standard 170 um

filter during routine transfusion and enters the recipient blood

stream.

• Some authors believe that this contributes to posttransfusion

pulmonary dysfunction and posttransfusion kidney

dysfunction.

• These authors advocate the use of 40 um blood filter for

patients undergoing massive BT.

RECENT CHANGES IN ATTITUDES AND PRACTICES TOWARDS BLOOD TRANSFUSION

Because we know now more about the hazards and

complications of BT, there are now significant changes in

the attitudes and practices of BT. So that

1- Autologous blood :is more widely used than ever where up to 6 units of patient’s blood

can be withdrawn over three weeks to be retransfused during

surgery and postop. This practice markedly reduced the need for

homologous blood for elective surgeries.

2- Use of cell savers :These machines essentially take sequestered and collected patient’s

blood in the surgical field, wash RBCs, filter them and return

washed viable RBCs to the patient.

3- Use of component blood therapy when applicable:

So that, only the needed component is given to the patient e.g., factor

VIII and the rest of the blood is used for other patients.

Bl.therapy2012

Health & Medicine

Transcript of Bl.therapy2012