CLINICAL PHARMACOLOGY
Action
GELFOAM Sterile Sponge has hemostatic properties. While
its mode of action is not fully understood, its effect appears to be more
physical than the result of altering the blood clotting mechanism.
When not used in excessive amounts, GELFOAM is absorbed
completely, with little tissue reaction. This absorption is dependent upon
several factors, including the amount used, degree of saturation with blood or
other fluids, and the site of use.
When placed in soft tissues, GELFOAM is usually absorbed
completely within four to six weeks, without inducing excessive scar tissue.
When applied to bleeding nasal, rectal, or vaginal mucosa, it liquefies within
two to five days.
HEMOSTASIS: GELFOAM Sterile Sponge, used dry or saturated
with sterile sodium chloride solution, is indicated in surgical procedures as a
hemostatic device, when control of capillary, venous, and arteriolar bleeding
by pressure, ligature, and other conventional procedures is either ineffective
or impractical. Although not necessary, GELFOAM can be used either with or
without thrombin to obtain hemostasis.
Clinical Studies
GELFOAM Sterile Sponge is a water-insoluble, hemostatic
device prepared from purified skin gelatin, and capable of absorbing up to 45
times its weight of whole blood.10 The absorptive capacity of
GELFOAM is a function of its physical size, increasing as the size of the
gelatin sponge increases.11
The mechanism of action of surface-mediated hemostatic
devices is supportive and mechanical.11 Surface-acting devices, when
applied directly to bleeding surfaces, arrest bleeding by the formation of an
artificial clot and by producing a mechanical matrix that facilitates clotting.4
Jenkins et-al 8 have theorized that the clotting effect of GELFOAM may be due
to release of thromboplastin from platelets, occurring when platelets entering
the sponge become damaged by contact with the walls of its myriad interstices.
Thromboplastin interacts with prothrombin and calcium to produce thrombin, and
this sequence of events initiates the clotting reaction. The authors suggest
that the physiologic formation of thrombin in the sponge is sufficient to
produce formation of a clot, by its action on the fibrinogen in blood.8
The spongy physical properties of the gelatin sponge hasten clot formation and provide
structural support for the forming clot.4,5 Several investigators
have claimed that GELFOAM becomes liquefied within a week or less and is
completely absorbed in four to six weeks, without inducing excessive scar
formation.7,10,12,13,14 Barnes13 reviewed experiences
with GELFOAM in gynecologic surgery. No excessive scar tissue, attributable to
the absorption of GELFOAM, could be palpated at postoperative examination.
Animal Pharmacology
Surface-acting hemostatic devices, when applied directly
to bleeding surfaces, arrest bleeding by providing a mechanical matrix that
facilitates clotting.4,5,6,7 Due to their bulk, surfaceacting hemostatic
agents slow the flow of blood, protect the forming clot, and offer a framework
for deposition of the cellular elements of blood.4,5,6,8 MacDonald
and Mathews9 studied GELFOAM implants in canine kidneys and reported
that it assisted in healing, with no marked inflammatory or foreign-body
reactions.
Jenkins and Janda5 studied the use of GELFOAM
in canine liver resections and noted that the gelatin sponge appeared to offer
a protective cover and provide structural support for the reparative process.
Correll et al7 studied the histology of
GELFOAM Sterile Sponge when implanted in rat muscle and reported no significant
tissue reaction.
REFERENCES
4. Guralnick W, Berg L: GELFOAM in oral surgery. Oral
Surg 1948; 1:629-632.
5. Jenkins HP, Janda R, Clarke J: Clinical and
experimental observations on the use of gelatin sponge or foam. Surg 1946;
20:124-132.
6. Jenkins HP, Janda R: Studies on the use of gelatin
sponge or foam as a hemostatic agent in experimental liver resections and
injuries to large veins. Ann Surg. 1946;124:952-961.
7. Correll JT, Prentice HR, Wise EC: Biologic
investigations of a new absorbable sponge. Surg Gynecol Obstet. 1945;
181:585-589.
8. Jenkins HP, Senz EH, Owen H, et al: Present status of
gelatin sponge for control of hemorrhage. JAMA 1946; 132:614-619.
9. MacDonald SA, Mathews WH: Fibrin foam and GELFOAM in
experimental kidney wounds. Annual American Urological Association, July 1946.
10. Council on Pharmacy and Chemistry: Absorbable Gelatin
sponge - new and nonofficial remedies. JAMA. 1947; 135:921.
11. Goodman LS, Gilman A: Surface-acting drugs, in The
Pharmacologic Basis of Therapeutics, ed 6. New York, MacMillan Publishing Co. 1980,
p 955.
12. Treves N: Prophylaxis of postmammectomy lymphedema by
the use of GELFOAM laminated rolls. Cancer 1952; 5:73-83.
13. Barnes AC: The use of gelatin foam sponges in
obstetrics and gynecology. Am J Obstet Gynecol 1963; 86:105-107.
14. Rarig HR: Successful use of gelatin foam sponge in
surgical restoration of fertility. Am J Obstet Gynecol. 1963; 86:136.