| |
Products / Services
Plasma derived products
There are wide ranges of plasma products available with
specific indications for their use. All plasma products
utilise liquid or frozen plasma as their starting material.
This may then be subjected to simple physical or more complex
chemico-physical processing to produce specific products;
the latter are termed plasma derivatives.
The various products, usage guidelines, and recommended
dosage schedules are outlined below. Clinicians should be
aware that all these products are antigenic and are potentially
capable of causing allergic or anaphylactic reactions. The
patient should be observed as for cellular products during
the initial 15 minutes of any transfusion.
Fresh Frozen Plasma
Fresh frozen plasma is separated from anticoagulated whole
blood within 18 hours of donation. This is done by separating
the plasma in a closed sterile system and freezing it to
below -18 °C. It contains all the clotting factors in
normal physiological levels. Fresh frozen single donor plasma
carries the same risk of latent viral infection as a unit
of red cell concentrate. However, a lyophilised fresh plasma
product (Bioplasma FDP), aliquoted from large pools of plasma
and treated with a solvent-detergent preparation to inactivate
undetected lipoprotein coated viruses is available from
National Bioproducts Institute in 50 ml and 200 ml volumes
when reconstituted. Other areas, at the time of writing,
are introducing retested quarantined FFP as an alternative
method of avoiding window period infections. Indications
and dosages for both products are similar.
FFP must be thawed before use according to the instructions
detailed on the package, or by the hospital blood bank before
issue. In the case of FDP reconstitute according to the
guidelines provided by the manufacturer.
Notes:
Units of FFP must be administered through a blood giving
set after thawing at 30-37 oC. Compatibility testing is
not required but units should be ABO compatible with the
patient's red cells, especially if large volumes are to
be transfused. If the ABO group of the patient is not available
then group AB fresh frozen plasma should be used as it contains
no A or B isoagglutinins.
Transfuse as rapidly as possible, at 15-20 minutes per unit
in the average adult in order to obtain a good clinical
effect. The labile coagulation factors deteriorate within
a few hours of thawing or reconstitution.
Specific Coagulation Factor
Products
All these products are produced from fresh frozen plasma
and are used in a variety of bleeding disorders when one
or other of the coagulation factors is deficient.
Dosage Schedule
The levels of Factor VIII or other relevant factor should
be monitored throughout therapy. This facility may not be
available in areas away from major treatment centres and
dosage schedules may have to be empirically applied therefore
as suggested below. However, elective major surgery in haemophiliacs
and treatment of major haemorrhage should be undertaken
only at centres where access to proper monitoring is available.
Contact your local haematologist or haemophilia treatment
centre for help.
Factor VIII has a half-life of 8-12 hours so treatment should
be given every 8-12 hours for at least the first 24 hours
and then every 12 hours. After major surgery the transfusions
may be required on a scheduled basis for at least 10 days.
Following transfusion of Factor VIII there is a more prolonged
rise in Factor VIII in patients with vWD; therefore transfusions
of concentrate for vWD are usually required only every 24
hours.
Haemophilia A
When haematological monitoring is available the number of
Factor VIII units required may be calculated from the following
formula:
Note:
All elective surgery should be undertaken in a specialist
centre.Transfusion of factor should be rapid. Patients should
be observed carefully for any untoward reaction to the product,
particularly those of allergic nature. See Reactions "Allergic/Anaphylactic"
(Section 11).
When monitoring is available (recommended for all major
operations) more exact regimens can be followed. Continuous
transfusion regimens are also efficacious and may well provide
more consistent haemostatis levels. These regimens should,
however, be under specialist supervision.
It should be borne in mind that about 10% of Haemophilia
A patients have antibodies (inhibitors) to Factor VIII and
these patients may not respond to the therapy described
above. These patients must be referred to a specialist haemophilia
treatment centre as an emergency.
Von Willebrand Disease
(VWD)
Intermediate purity Factor VIII concentrates are the treatment
of choice where DDAVP (vasopressin analogue) is not effective.
The local products contain adequate amounts of high molecular
weight multimers.
Dosage
- Use Factor VIII units as a measurable entity.
- Using 30 iu units of Factor VIII per kg.
- Monitor every 24 hours.
- If bleeding persists despite adequate levels
of Factor VIII, then transfuse Cryoprecipitate (10-20
iu units FVIII per kg) or Random platelet concentrate
(1 concentrate per 10 kg).
Haemophilia B
The clinical picture of Haemophilia B is identical to that
of Haemophilia A, and the levels required are similar to
those of Haemophilia A, although slightly lower levels of
Factor IX are usually adequate for normal haemostasis. Factor
IX has a longer half-life than Factor VIII (up to 24 hours)
and therefore only daily doses may be required. For prolonged
therapy (> 5 days) a pure Factor IX concentrate is preferable
since prolonged Factor IX complex transfusion has been reported
to lead to thrombosis. The reports however only refer to
concentrates manufactured outside South Africa. There have
been no reports of thrombosis with the local product. When
haematological monitoring is available the number of Factor
IX units required may be calculated from the following formula:
If monitoring is not available, give 10-20 iu/kg as a daily
or twice daily dose regime. Do not give in conjunction with
Cyclokapron® or Amicar®.
Hypofibrinogenaemia
Other Plasma Products
Albumin 20% Solution
Prepared by fractionation of a large pool of plasma. The
process involves steps like pasteurisation and cold ethanol
fractionation, which inactivates viruses such as HIV and
hepatitis virus.
Practical Note:
Volume expansion in acute hypovolaemia is more appropriately
obtained using crystalloid or synthetic colloid solutions.
In a dehydrated patient it is inappropriate to use 20% Albumin
solution as a volume expander. If a physiological albumin
solution is required then add 100 ml 20% albumin to 400
ml saline or Ringers lactate. There is a 4% product available
from NBI.
In thermal burns the early restoration of fluid volume is
best achieved with crystalloids. Albumin may be given 8-12
hours after the onset of the burn
Dosage:
- Calculate the patient's plasma volume from
the following formula
- Calculate the number of grams of albumin
required for a particular patient as follows:
Since half the albumin transfused will diffuse
into the extravascular compartment it is necessary to use
this multiplication factor to achieve the desired intravascular
levels.
Products available
- 4% Albumin in 8 g/200 ml and 16 g/400 ml
bottles (NBI).
- 20% albumin in 20 g/100 ml, 10 g/50 ml
bottles (WPBTS, NBI).
Note:
Assess carefully before administering to any patient with
known hypersensitivity to human proteins.
Stabilised Human Serum
Stabilised Human Serum is prepared from large pools of donor
plasma that is subjected to:
- Selective absorption of lipoprotein, coagulation
factors, and complement components.
- Reduction of viral content by the above
processes and by ultra violet irradiation.
- A heat treatment step that is licensed
as a validated viral inactivation procedure for HIV.
- The resultant stable protein solution contains
a wide and constant spectrum of antibodies in the IgA,
IgM and IgG classes, many of the transport proteins, and
albumin. It provides an ideal physiological volume expander
in a volume equivalent to that lost.
Usage
Administration
- Adults: Intravenous transfusion to a dosage
of up to 8 units of 250 ml per 24 hours.
- Children: 3-6 ml per kg per 24 hours.
Side effects
- Transient urticarial reactions.
- Pyrexia.
- Rigors.
- Hypotension.
Treatment of side effects
Stop transfusion, and administer antihistamines, prednisone,
or hydrocortisone either intramuscularly, or intravenously,
depending on the severity of the symptoms.
Important:
Do not give to any patient with a known sensitivity or allergy
to human protein solutions.
Immunoglobulin Therapy
Immunoglobulin is the antibody-containing
fraction of human plasma that is obtained by the fractionation
of pooled plasma units, all of which have been tested and
found non-reactive for HBsAg, anti-HCV, anti-HIV and p24
HIV antigen. Specific hyperimmune immunoglobulin preparations
are prepared from plasma from donors with high titres of
specific antibodies. The manufacturing process per se for
immunoglobulins has virucidal effects and preparations used
and manufactured in South Africa have never been reported
to transmit hepatitis or HIV. More recently introduced intravenous
products contain specific viral inactivation steps for lipid
enveloped viruses.
Practical Note:
Anaphylactic reactions may occur if an intramuscular product
is used intravenously.
Anaphylactic or severe allergic reactions may occur if the
patient suffers from IgA deficiency, or has experienced
a previous severe reaction to human protein product.
back
|
|