Normal blood coagulation Definition of Haemostasis refers to
Normal blood coagulation
Definition of Haemostasis : refers to the arrest of bleeding, by prevention blood loss the blood vessels,
mechanism of coagulation: - fibrinolysis : dissolving of clotting to maintain patency of circulation
How Blood clotting occurs** • -tissues are damaged : platelets break down, thromboplastin is released. • 2 - prothrombin converted into thrombin by assistance of calcium ions, and thromboplastin
• 3 -Thrombin is a proteolytic (protein-splitting) enzyme that converts fibrinogen into fibrin. • -Fibrinolysis is the breakdown of fibrin and occurs as a response to the presence of clotted blood
- heparin, which is produced in the liver make dissolving of this fibrin blood clot * characteristics of Fibrin: - a network of long, sticky strands that entrap blood cells(coagulation material ) to establish a clot
• -The coagulated material: clotting factors. 13 in number. • -breaks down the fibrin in the clots, by plasmin will produces fibrin degradation products (FDPs).
• Disseminated intravascular coagulation • Definition : DIC is a situation of inappropriate coagulation within the blood vessels. • Result : • 1 -consumption of clotting factors. • 2 -failure of clotting at the bleeding site.
• *DIC is rare when the fetus is alive, and it usually starts to resolve when the baby is born • Etiology: • DIC is never a primary disease • it always occurs as a response to another disease process • . pathology : • formation of micro thrombi throughout the circulation. • Clotting factors are used up.
The DIC triggers fibrinolysis and the production of FDPs. A paradoxical feedback: clotting is the primary problem, but hemorrhage is the predominant clinical finding.
When DIC occurs during or after birth. 1 -reduce level of clotting factors. 2 -the presence of FDPs , so action of FDPs;
• 1 - prevent normal haemostasis at the placental site. • 2 - FDPs reduce the efficiency of normal clotting. • 3 - inhibit myometrial action • 4 -prevent the uterine muscle from constricting the blood vessels in the normal way.
• • Picture : -Torrential hemorrhage may be the outcome. -Visible blood loss may be observed. -blood remain uncoagulated for several minutes and even when clotting does occur, the clot is unstable
• -*Micro thrombi may cause: • - circulatory obstruction in the small blood vessels. • - cyanosis of fingers and toes. • - cerebrovascular accidents • - failure of organs such as the liver and kidneys
Events that trigger DIC • Placental abruption • Intrauterine fetal death including delayed miscarriage • Amniotic fluid embolism • Intrauterine infection including septic abortion • Pre-eclampsia and eclampsia
Placental abruption@@ • -damage of tissue at the placental site , thromboplastin are released into the circulation and may cause DIC. • -If the placenta is delivered as soon as possible after the abruption the risk of DIC is reduced. • (Vaginal birth where possible is often favored over caesarean birth to reduce the risk of postpartum hemorrhage. )
Intrauterine fetal death@@ • -If a dead fetus is retained in utero for more than 3 or 4 weeks, • -thromboplastins are released from the dead fetal tissues. • - thromboplastein enter the maternal circulation and deplete clotting factors. • - IOL should be done, with the woman's consent. • -clotting studies should be performed prior to induction of labor
Amniotic fluid embolism@@ • - DIC may develop, through release of Thromboplastin in the amniotic fluid is responsible for setting off the cascade of clotting.
@@Intrauterine infection The causes of this include; -Septic abortion. - Hydatidiform mole. -placenta accretes - Endometrial infection before or after birth. * DIC is caused by endo toxins entering the circulation and damaging the blood vessels. • -The infection itself must be treated with antibiotics • • •
• -monitor for developing hemolytic septicemia, any blood administered may be destroyed by the bacteria in the bloodstream. • -The baby needs treatment following birth if the infection was ante partum. --In postpartum infection, any retained products may need E&C
: Pre-eclampsia and eclampsia@@ • -predispose woman to abruption placenta that could lead to DIC
Management: • -The midwife should be alert for signs that clotting is abnormal • - Assessment of the nature of the clot, during the third stage of labor. • -Oozing from a venepuncture, bleeding from nose or mouth should be observed. • . CBC and blood group. • -clotting studies. • -platelets count. • - Fibrinogen and FDPs
Treatment: • --replacement of blood cells and clotting factors. • - Administration of fresh frozen plasma and platelet. • - The use of fresh whole blood is not now common. • -Management is carried out by a team of obstetricians, anesthetists, hematologists, midwives and other health professionals
Care by the midwife • -. The midwife has to maintain her own calmness and clarity of thinking as well as helping the couple to deal with the situation. • - Frequent and accurate observations must be maintained in order to monitor the woman's condition. • -Blood pressure, respirations, pulse rate and temperature are recorded.
• The general condition is noted. • - Fluid balance is monitored for any sign of renal failure. • - The midwife must give him appropriate attention. • -kept informed of what is happening. • -psychological support
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