الفهرس 
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Abstract
Normal hemsotasis is dependent on precisely regulated
interactions between the blood vessel wall, platelets
and plasmas clotting factors, the hemostatic mechanism
includes: vascular spasm, formation of platelet plug, blood
coagulation and growth of the fibrous tissue into the blood
clot to close the hole in the vessel permanently, within
seconds of the vessel injury, activated platelets aggregate,
forming a hemostatic plug in an initial process called
”primary hemostasis”. It is accompanied by activation of the
plasma coagulation system and the formation of a definitive
fibrin clot, a process called ”secondary hemostasis”.
The coagulation cascade consists of intrinsic and
extrinsic pathways, which terminate in a final common
pathway.
Fibrinolytic system prevents extension of the clot
formation to the surrounding tissues.
Coagulation disorders either disorders of hemostasis or
disorders of thrombosis.
Disorders of hemostasis either be inherited or acquired, most
common inherited disorders are hemophilias and von
Willdebrand’s disease.
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Summary
109
Hemophilias are characterized by deficiency of
coagulant factors which lead to increase bleeding at surgery
and in the postoperative period, hemophilias are either
hemophilia A, B or C.
von Willebrand’s disease is an inherited bleeding
disorder secondary to vWF deficiency. vWF is important for
primarily in platelet adhesion to the subendothelial layer of
the exposed endothelium, in addition, it carriers the factor
VIII molecules in the plasma.
Acquired disorders of hemostasis including multiple
diseases such as, Vitamin K deficiency which is necessary
for promotion of formation of four of the most important
clotting factors (II, VII, IX and X).
Consumption coagulopathy (DIG) which characterized
by widespread small vessel thrombosis associated with
generalized bleeding as a result of consumption of the
coagulation factors and excessive flbrinolysis. it may occur
secondary to trauma, sepsis, malignancies.
Thrombocytopenia is one of the causes of excessive
bleeding during surgery, it is either idiopathic or secondary
to drug intake, malignancy or postinfection.
Summary
110
Idiopathic thrombocytopenic purpura is a persistent
thrombocytopenia, caused by antiplatelets immunoglobulins
low platelet count.
Intraoperative bleeding may reflect not only alteration
in the number but also the function of circulating platelets
and procoagulants.
Coagulation disorders may be predisposed by
pathology elsewhere include renal diseases, liver diseases,
SLE or hematological malignancy.
Disorders of thrombosis ”hypercoagulable state” are
either congenital or acquired occur when there is an
imbalance between the anticoagulant and procoagulant
activities of plasma in which the procoagulant activities
predominate. Antithrombin III, protein C and protein S
deficiencies are the most common hypercoagulable state.
Evaluation of the coagulation state depends upon a
proper history taking, physical examination and laboratory
tests. The most commonly used are proghtombin time (PT)
which evaluates the extrinsic and the common pathways, and
partial thromboplastin time (PTT) which evaluates the
intrinsic and the common pathways, other tests including
clotting time, bleeding tine and specific estimation of the
coagulation factors, also thrombo-elastography is a rapid and
reliable method of testing the entire coagulation systems.
Summary
111
Preoperatively, the patient is assessed and specific
replacement therapy (e.g. FFP, cryoprecipitate, ...) is given as
required.
Premedication of these patients, intramuscular injection
should be avoided to guard against hematoma formation.
Intraoperatively, the choice of anesthesia between
regional and general techniques is done according to the
patient coagulation state and during the operation, the
amount of bleeding should be closely observed.
Postoperatively, patient is observed closely to diagnose
any abnormal bleeding. As with premedicants, postoperative
pain relief it is better to avoid intramuscularly injected drugs.