Biomedical Engineering Reference
In-Depth Information
Table 11.1
Recommendations for prophylactic platelet transfusions
The threshold of 10 × 10
9
/L is as safe as the higher levels for the majority of patients without
the additional risk factors;
Risk factors include sepsis, usage of drugs such as antibiotics, and other abnormalities of
hemostasis;
Platelet transfusions were also considered to be necessary at higher thresholds in immunosup-
pressed patients than in adults;
Higher threshold (50-100 × 10
9
/L) for platelet transfusions are needed to cover the invasive
procedures (splenectomy, bone biopsy);
In acute DIC or massive blood transfusion with thrombocytopenia (platelet count <50 × 10
9
/L),
platelet transfusions should be used in addition to coagulation factor replacement.
There are two main hazards of allogeneic RBC transfusions: the virus transmis-
sion and risk of acute immune-mediated hemolytic transfusion reaction (HTR). The
majority of HTRs results from administration of ABO-incompatible RBCs.
Sometimes RBC transfusion errors in practice lead to life-threatening and even fatal
consequences. Many factors contribute to these errors, resulting from the
misidentification of either the patient or the blood product. The HTR reaction could
be promptly detected (careful monitoring of patient) and treatment quickly initiated
[
4-
6,
14-
16
] .
Platelet Transfusion Practice
Platelet concentrates (PCs) are suitable for prophylaxis or treatment of bleedings in
patients with thrombocytopenia after SC transplant. Therapeutic use of PC is very
effective, but the issue of the benefit of prophylactic platelet transfusion in preven-
tion of hemorrhage remains controversial. A number of patients require specialized
PCs, including leukodepleted (filtered), gamma-irradiated, or HLA-matched com-
ponents [
17
] .
Numerous reports, related to the determination of “platelet transfusion trigger”,
i.e., a threshold for their clinical use (Table
11.1
) based on platelet count, have
occurred recently [
18-
25
] . Typically, severe hemorrhage (hematuria, hematemesis,
and melena) is present at platelet counts £ 5 × 10
9
/L. However, there are reports on
cases of rare and moderate bleedings in patients with around 5 × 10
9
/L platelets (due
to the possible existence of a critical “individual thrombocytopenic bleeding thresh-
old”). However, decision related to the introduction of PC transfusion should never
be made exclusively upon the patient's platelet count [
1
] . Two types of platelet
components are available in most hospital settings: platelet concentrates (“random-
donor platelets”) and apheresis-derived platelets (“single-donor platelets” or “pher-
esed platelets”). They differ in methods of preparation, platelet contents, and
potential for adverse effects in the transfusion recipient. However, the hemostatic
activity of platelets is similar in each component. At least, daily dose of platelets
is approximately 0.5 × 10
10
cells per kg of patient's body mass [
8,
11,
25-27
] .
