Paediatric Red Blood Cell Exchange Introduction Baba Inusa Adult Perspective Neil Westerdale Paediatric and adolescents Luhanga Musumadi 24th September, 2008 HCK
Indications for Transfusion in Sickle Cell Disease 2. sickling by lowering Hb S conc. Prevention of recurrent stroke or first clinical stroke (abnormal TCD) Chronic debilitating painful crises Chronic lung disease with arterial hypoxaemia HCK
Complications of Longterm Transfusion Transfusional Iron Overload
Delayed growth and sexual maturation due to endocrine disturbances Diabetes mellitus Cirrhosis Cardiac arrhythmias and heart failure Death >1520 yr. of chronic transfusion
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Complications of Transfusion Alloimmunization Transfusiontransmitted Infections
Transfusional Iron Overload
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Risk of Recurrent Stroke If presented within 24 hours of symptom onset, patients who received simple transfusion had a five times greater risk of recurrent stroke when compared to children who received exchange transfusion therapy (95% CI 1.3, 18.6). No difference in odds of recurrent stroke was found for any type of treatment after 24 hours of symptoms. HCK
Multivariate analysis
Risk of recurrent stroke was 8 times higher for patients receiving simple transfusion within 24 hours of symptoms and in the absence of an antecedent medical event (95% CI 1.6, 38.8).
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Risk of Recurrent Stroke (n= 81)
Cumulative Stroke-Free Interval
1.0
.8
Type of Transfusioin
.6
exchange transfusion exchange transfusion
.4
-censored simple transfusion
.2
simple transfusion -censored
0.0 0
5
10
15
20
25
Time from first stroke to second stroke (years after stroke) HCK
Pathophysiology
BLOOD VISCOSITY (cP)
7
6
5
4
Transfusion Pre – Post –
3
2 10
20
30
40
50
HAEMATOCRIT (%)
Jan et al, Transfusion,1982, 22(1):19 HCK
150
150
140
140
CBF [mL/100g/min]
CBF [mL/100g/min]
Why would exchange transfusion be better than simple transfusions for decreased risk of strokes?
130 120 110 100 90 80 8
8.5
9
9.5
10
10.5
11
130 120 110 100 90 80
11.5
Hb [g/dL]
5
10
15 20 25 30 35 40 45 50 55
HbS [%]
Hurlet-Jensen et al, Stroke, 1982, 25(8):1690 HCK
ERYTHROCYTAPHAERESIS Reduce or prevent iron accumulation while preventing recurrent stroke in patients with sickle cell disease and stroke
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Rationale for Erythrocytaphaeresis in Reducing Iron Overload With exchange transfusion, RBCs from patients are removed while donor RBCs are being given, resulting in fewer RBCs to contribute iron to the body in comparison with simple transfusion.
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Erythrocytaphaeresis Goals ◆ Removal of patient’s RBCs:
Reduction of blood viscosity in polycythemia Reduction of excessive iron in nonanemic hemochromatosis
◆ Exchange patient’s abnormal RBCs with normal RBCs: Hereditary or acquired RBC disorders HCK
Erythrocytaphaeresis in SCD
As a treatment or prevention of acute complications: ● Acute chest syndrome ● Stroke
● Preop (when Hb > 10 g/dl)
As a longterm transfusion therapy
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LongTerm Erythrocytaphaeresis Sickle Cell Dis with Stroke < first 3 yr
PreEx Hb S
< 30%
> 3 yr < 50%*
End Hb S (%) 12 15
20 25
End Hct (%)
27 36
27 36
• Patient must be clinically and neurologically stable before raising the target Hb S to <50% from <30%. HCK
Acute Erythrocytaphaeresis Advantages
◆ Rapid in Hct level without volume overload ◆ Rapid Hb S level without substantially the Hct level ◆ rate of transfusional iron loading ◆ Duration of procedure shorter
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Longterm Erythrocytaphaeresis in SCD Advantages Reduces the transfusional iron accumulation Delays onset of transfusional ironinduced organ damage Delays initiation of iron chelation therapy Prevents the need for iron chelation therapy
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ERYTHROCYTAPHAERESIS Disadvantages ◆ Problem with venous access
◆ Increased blood usage
◆ Increased no. of donor exposure ◆ Increased cost for the proc. (?) ◆ Universally not available
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