Role
of Red Blood Cells in the Reduction of Blood Loss: The
hemostatic function of red blood cells to prevent non-surgical blood
loss is a current area of active investigation. Studies are being
done to document that red blood cells are very important in hemostasis
and transfusion of red blood cells to increase the hematocrit to
35 V% should be done in patients with non-surgical blood loss prior
to the transfusion of platelets and fresh frozen plasma.
Current
in vitro studies indicate that red blood cells may be responsible
to activate platelets to improve their function. Flow cytometric
studies of red blood cell and platelet surface markers are being
performed to determine the mechanism of the red blood cells action
on the platelet.
Role
of Poly-N-Acetyl Glucosamine (p-GlcNAc) in the Reduction of Blood
Loss in Patients Subjected to Cardiac Procedures and in Rodents
Subjected to Hemorrhagic Shock: A new polymer, poly-N-acetyl
glucosamine (p-GlcNAc) has been identified and found to be effective
in achieving hemostasis in surgical procedures and trauma. The p-GlcNAc
material is a unique polymer structure isolated and purified from
large scale cultures of a marine microalga. The p-GlcNAc polymer
structure has been determined via infra-red (FTIR), NRM and CD spectral
data and is characterized as an ordered and regular (pseudo-crystalline)
structure. This unique structure has been linked to the hemostasis
performance of the product. Other polymers containing N-acetyl glucosamine
such as chitin, chitosan, and hyaluronic acid do not have the same
structure and do not exhibit the hemostatic activity, as demonstrated
by in vitro and in vivo assays.
A bandage composed of the substance poly-N-acetyl glucosamine (p-GlcNAc
or NAG) has been shown to reduce bleeding and blood loss in animals.
The NAG bandage is being evaluated as a safe, simple and effective
method for minimally trained military personnel to reduce bleeding
time and blood loss in injured casualties.
The
NAG bandage may also be used to control blood loss following injuries
or surgical procedures in the civilian community. It is simple enough
so that the first medical personnel at the scene could control the
bleeding until the patient could be transported to the hospital.
In addition to saving lives lost due to uncontrollable bleeding,
the NAG bandage may also reduce blood transfusion requirements,
which may be an important issue in these times of severe blood shortages.
A symposium
on the results obtained with poly-N-acetyl glucosamine was held
at Brigham and Women's Hospital on February 25, 2003. The symposium
was organized by C. Robert Valeri, M.D. of the Naval Blood Research
Laboratory and hosted by Herbert Hechtman, M.D. of Brigham and Women's
Hospital and Harvard Medical School. The
abstracts presented at this meeting may be reviewed here.
Taken
together the animal and clinical data indicate that poly-N-acetyl
glucosamine, an FDA approved agent manufactured by Marine Polymer
Technologies Inc is an effective hemostatic agent whether applied
directly to gastric varices; topically against bleeding surfaces
of spleen or liver; against major wounds of the abdominal aorta;
or on cardiac cathetherization sites in the groin.
Hemostasis
was achieved, even in the presence of full heparinization and in
acquired and congenital hemostatic defects. The mechanism of action
is due to local vasoconstriction and by the activation of the clotting
cascade through platelets and red cell activation.
The
preclinical and clinical data presented at this symposium support
a role for poly-N-Acetyl glucosamine in medical and surgical conditions,
particularly in trauma.
Effect
of Zeolite (QuikClotTM) To Reduce Blood Loss:
Studies are currently being done to assess the safety and efficacy
of zeolite as a hemostatic agent
In
vitro studies done to date have shown that addition
of zeolite to platelet rich plasma allowed the platelet-rich plasma
to quickly form a clot. Additional studies have shown that addition
of zeolite to platelet-rich plasma results in activation of the
platelets along with release of platelet-derived growth factors.
Platelets treated with zeolite produced about four times the platelet-derived
growth factors than untreated platelet-rich plasma. Additional studies
are being performed to determine how the zeolite interacts with
red blood cells, platelets and plasma proteins to form the clot.
Studies
were performed in rodents subjected to blood loss which demonstrated
that the QuikClotTM method reduced
blood loss and mortality. The zeolite "QuikClotTM" was
shown to be effective in reducing blood loss and improving survival.
Studies are being performed to determine if treatment with zeolite
produces adverse effects.
You
may review a PowerPoint presentation
of the study that was done to evaluate the safety and therapeutic
effectiveness of zeolite (QuikClot™) to restore hemostasis
in the rodent and to assess the mechanism of action of zeolite on
blood in vitro. (This slide show was presented at the annual ATACCC
(Advanced Technical Applications for Combat Casualty Care) meeting
held in St. Pete, FL in August 2003.)
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