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By DR. SUGUNA. R. KUMAR,
Professor of OBG,
Al-Ameen Med College,
Bijapur, Karnataka.
There are many controversies regarding
blood transfusion. Like when to transfuse? What to
transfuse? And How much to transfuse?
The purpose and scope of Blood
Transfusion are
• Maternal mortality due to obstetric hemorrhage is 25-30%
and anemia is 15%, both these condition require blood
transfusion.
• Studies show that there is inappropriate transfusion in
15-45%, either transfusion done in not indicated cases or
too late or too little done in indicated cases.
• Rising cost and non availability of blood, risk of
transfusion reaction, transmission of infections has made us
to limit transfusion only in indicated cases.
Nowadays only blood components are used
instead of whole blood.
The blood components are
-Packed red cells,
-Platelet concentrate,
-Fresh frozen plasma,
-Cryoprecipitate,
-Human plasma proteins like albumin, coagulation factor
concentrates, Immunoglobulins.
-Specialized products: CMV negative or leuko-reduced blood
and Type specific or HLA matched platelets.
Adverse effects of blood transfusion
are:
1) Transfusion reaction:
Non hemolytic reaction: fever, chills, urticaria occurs in
1-5% of all transfusion
Hemolytic reaction: due to incompatible blood is a life
threatening complication
2) Transfusion-transmissible diseases: HIV-1, HIV-2,
hepatitis B and C, other hepatitis viruses, syphilis,
malaria, CMV, brucellosis, Chaga’s disease.
3) TRALI- transfusion related acute lung injury, where
injury to pulmonary capillaries by lipid products stored
components, leukocyte reaction.
4) Bacterial contamination of blood
Always follow Guidelines before blood transfusion.
Guidelines offer guidance about appropriate use of blood
products, so that neither the women is compromised nor
exposed to unnecessary risk.
-RCOG Guidelines. 2007. formulated from
databases of randomized controlled trials, systemic reviews
and meta-analysis from 1966-2006 from the Cochrane library,
TRIP, Medline and PubMed.
-WHO Guidelines, Geneva. 2001.
-American Society of Anesthesiologist Task Force on Blood
Component Therapy, 1996 which included 9 anesthesiologist,
one physician, college of American pathologist, ACOG and
methodologist. Based on 160 studies on use of blood
component in perioperative and peripartum period.
WHO prescribes a checklist before
prescribing Blood:
1) What improvement in the patient’s
condition am I to achieve following the blood transfusion?
2) Can I minimize the blood loss to reduce the transfusion?
3) Are there any other treatment like I.V replacement fluid
and oxygen?
4) What are the specific clinical and lab indications for
transfusion?
5) What are the risks of transmitting infectious agent?
6) Do the benefits of transfusion reaction outweigh the
risks?
7) What other options are there if no blood is available in
time?
8) Will the trained person monitor and respond immediately
if any acute transfusion reactions occur?
9) Have I recorded my decision and reasons for transfusion
on patient’s chart and the blood request form?
RCOG recommends reduction of blood
transfusion by:
1) Treatment of ANEMIA must.
2) Hb% of 10.5g/dl indicates hematinic deficiency, exclude
hemoglobinopathies.
3) Oral iron preferred in the treatment of anemia. Parental
iron only in intolerance to oral, absorption defects,
doubtful compliance of patient.
4) Recombinant human erythropoietin (rHuEPO) used only in
end stage renal disease.
5) Hemoglobinopathies and bone marrow failure syndrome
treated by blood transfusion in close conjunction with
hematologist.
6) Active management of 3rd stage or labour proved to
decrease incidence of blood transfusion.
7) High risk of hemorrhage patients advised hospital
delivery only.
8) Optimal management of women on anticoagulants.
General principles of blood transfusion
are (RCOG)
- Blood grouping and antibodies should
be done at booking and at 28weeks.
- Patient blood sample for cross matching should be ideally
fresh, group and save sample in case of high risk patients
(placenta previa, accrete), sample should not be more than 7
days old.
- Only Kell negative blood should be used in women of child
bearing age.
- CMV seronegative red cells and platelets for seronegative
women.
Minimize the use of banked blood by
- Pre- autologus deposit of blood. In pregnancy this is not
advice.
- Acute normovolemic hemodilution: Removal of predetermined
volume of blood prior to surgery, replaced by crystalloids
and subsequent reinfusion of the removed blood.
- Intraoperative blood salvage: If blood loss of >1500ml
expected. In pregnancy there is a risk of amniotic fluid
embolism and contamination with fetal cells.
- Autologus blood transfusion in ruptured ectopic and
reactionary hemorrhage in postoperative cases.
Normal blood volume is 7% of ideal body
weight and it increases to 8-9% in pregnancy.
Massive blood loss is loss of 1 blood volume in 24hours or
50% of blood volume loss in 3hours or loss at a rate of
150ml/minute.
Clear protocol to manage obstetric hemorrhage involving
obstetrician, anesthetist and hematologist and blood bank is
recommended. This should be practiced in ‘fire drills’ with
trained personnel. (RCOG)
In hemorrhagic shock primary
compensation is by increase in cardiac output, autonomous
nervous system preserves oxygen delivery to CNS and heart,
sparing the skin, fat, kidneys. Thus changes in the
microcirculation affects oxygen transport at the tissue
level. Urine output is most important in monitoring the
circulation.
Clinical features of hemorrhagic shock:
- Class I hemorrhage: - with loss of 15% of total blood
volume, little hemodynamic affect occurs; there is
vasoconstriction and mild tachycardia.
- Class II hemorrhage: - with loss of 15-30% of total blood
volume there is tachycardia, decrease in pulse pressure,
anxiety and restlessness
- Class III hemorrhage: - with loss of 30-40% of total blood
volume there is marked tachycardia, tachypnea, systolic
hypotension, altered mental status. Young healthy women can
still be treated with crystalloid therapy but blood
transfusion also recommended.
- Class IV hemorrhage:- with loss of >40% of total blood
volume marked tachycardia and hypotension, narrow pulse
pressure, low urine output depressed mental status if not
treated with crystalloids and blood is life threatening.
Estimation of blood loss is always
inaccurate. Visual estimation of blood loss is not reliable
because of inaccuracy in blood loss measurement,
intercomparmental fluid shift during shock and dilution
effect of crystalloid therapy also make hematocrit
estimation not reliable method. Thus clinical evaluation of
the patient is most important in the management of
hemorrhagic shock
Factors affecting the response to
decrease Hb in hemorrhage are:
- Cardiopulmonary reserve – depending
on the preexisting cardiac and pulmonary disease and
hemodynamic indexes, this is also affected by drugs and
anesthetics administered.
- The rate and the magnitude of blood loss.
- Oxygen consumption is affected by the body temperature,
drugs, anesthetics, sepsis, and muscular activity of the
patient.
- Preexisting atherosclerotic disease.
- Anemia (normovolemic hemodilution) and preeclampsia (hemoconcentration)
Management of Obstetric hemorrhage:
1) Identify the cause of hemorrhage.
2) Two I .V started of large caliber.
3) Fluid replacement by crystalloids 3 times the estimated
blood loss, rapid equilibration occurs, 20% seen in
circulation after 1hour. Survival reduced in hemorrhage
managed with blood alone. 6% excess mortality in albumin
(colloid ) treated non pregnant patients.
4) Blood replacement in class III & class IV hemorrhage.
Compatible whole fresh blood is ideal (but not available)
70% of red cells function for 40days, coagulation factors
present and plasma expands the hypovolemia.
5) Packed red cells and crystalloid infusion mainstays
therapy in hemorrhage.
6) Transfusion of 1 unit of whole blood or RBCs increases
hematocrit by 3% or Hb by 1g/dl in a non-bleeding adult.
• Thus blood transfusion is indicated
only on clinical, hematological grounds and development of
inadequate oxygenation (when Hb is between 6-10g/dl)
• Rarely done when Hb is 10g/dl and always indicated when
<6g/dl
• 10/30 rule outdated (Hb-10g/dl, hematocrit of 30%), single
unit transfer not beneficial, hazard and risks far outweigh
the benefit of transfusion. (ACOG)
• Physiological markers of impaired tissue oxygenation is
Oxygen extraction ration (O2E2) is superior, Oxygen
extraction monitored continuously by using pulse oximetry
(arterial O2 saturation) and mixed venous oximetry (venous
O2 saturation)
Whether blood should warmed prior to
transfusion?
Warming of blood not beneficial, if the rate of flow is
>50ml/hr clinically significant cold agglutinins present
then warm the blood. Blood warmer is ideal never use hot
bowl causes hemolysis which is life threatening. Keeping the
patient warm is important (WHO)
Does hypocalcemia occur with
administration of blood?
With 4-5units of transfusion calcium binds with citrate
preservatives. This is self resolving with metabolism of
citrate by liver and kidney. Hypocalcemia will not impede
blood coagulation. Hypocalcemia with hypothermia and
acidosis is dangerous will decrease cardiac output, causes
bradycardia and dysrhythmia thus calcium gluconate indicated
here (WHO)
Coagulopathy
• Dilution coagulopathy occurs in major
blood loss treated by volume replacement by crystalloids,
colloid and transfusion of red cell component, stored whole
blood.
• Obstetric conditions like amniotic fluid embolism,
placental abruption, pre-eclampsia cause DIC, also in septic
abortion secondary to tissue trauma which activates the
coagulation cascade.
• Clinically suspect DIC when there is profuse bleeding from
trauma site, oozing from IV insertion and venesection site.
Platelet transfusion
1 unit of fresh blood raises platelet
count by 10,000-15,000/cumm. Transfusion of 1 platelet
concentrate (50ml) increases the count by 5-10x109/l.
Platelet transfusion indicated in (RCOG)
- Count of <50x109/l, thrombocytopenia, platelet dysfunction
and micro vascular bleed with adequate platelet count.
- Safe margin is to keep a trigger of 75x109/l
- 50x109/l anticipated when 2 volume replaced by fluids or
5-10 units of red cell component transfusion
- Good communication with the transfusion laboratory must.
- Rh-ve women should receive Rh-ve platelets. Group
compatibility must. Anti D 250 IU is given if Rh+ve
platelets given in Rh-ve women.
- Platelet transfusion not effective when thrombocytopenia
is due to platelet destruction as in ITP, TTP, untreated DIC.
- Vaginal delivery and minor operative procedure can be done
with platelet of <50x109/l.
Fresh frozen plasma (FFP)
FFP contains stable clotting factors,
albumin, immunoglobulin and no platelet.
Full blood count (CBC) and coagulation screening advised
before advising FFP
FFP takes 30 minutes to thaw, once thawed used in 6 hours.
RCOG recommends
- Infusion of FFP ideally before 1 blood volume is lost.
- In DIC a combination of FFP, platelets and cryoprecipitate
indicated
- FFP indicated when fibrinogen is <100mg/dl and maintain
fibrinogen >1g/dl.
- FFP and cryoprecipitate ideally should be of same group of
the recipient. No need of anti-D prophylaxis in Rh-ve.
- FFP administered as 12-15ml/kg, to keep the activated
partial thrombhoplastin time (aPTT) and PT time ratio <1:5.
- Contraindicated for augmentation of plasma volume or
albumin concentration.
Cryoprecipitate
It is cold precipitable protein fraction derived from thawed
FFP AT 1-6º C. Contains factor VIII, fibrinogen,
fibrinonectin, vW factor and factor XIII.
1unit/kg body weight raises plasma fibrinogen by
approximately 50mg/dl in the absence of consumption or
massive bleeding.
Cryoprecipitate indicated in (ACOG)
- in von Willebrand’s, unresponsive to Desmopressin and
congenital fibrinogen deficiency in perioperative or
peripartum period
- Bleeding with fibrinogen of 80-100mg/dl.
Recombinant factor VIIa (rFVIIa)
therapy
Can be considered in life threatening PPH but this should
not delay life saving procedure for PPH. Whether it reduces
blood loss during Caesarean section is doubtful. It has a
pivotal role in initiating coagulation but efficacy and
safety still to be established. One can consider keeping a
stock in the blood bank.
Anemia in pregnancy
It is a normovolemic; oxygen delivery is adequate even at Hb
of 7g/dl. Anemia tolerated well even at a hematocrit of
18-25%, myocardial lactate flux not affected with Hb 6g/dl.
Heart failure occurs only when hematocrit is <10%. Chronic
anemia is better tolerated. There is increase in
2,3-diphosphoglycerate in RBCs which facilitates oxygen
delivery. There is no change in cardiac output until Hb
<7g/dl. Obstetric women tolerate well with no adverse affect
on mother and fetus.
Thus blood transfusion is indicated in antenatal period if
Hb is <6g/dl four weeks prior to delivery where there is no
time to give iron. This improves anemic status and oxygen
carrying capacity to withstand the strains of labour and
blood loss during labour. When Hb is <7g/dl in labour or
immediate post partum period, blood transfusion depends on
the medical history, age and symptoms. Fit and healthy women
require no blood transfusion even with Hb of <7g/dl.
Exchange transfusion rarely done, only in desperate cases of
cardiac failure with anemia, severe anemia requiring
surgery, severe anemia with hematocrit of 13% near term. In
sickle cell anemia repeated transfusion indicated thus
partial exchange transfusion done. In patients who refuse
blood transfusion or Jehovah’s witnesses optimize Hb before
delivery. Antenatal planning required to keep Hb above
10.5g/dl. Blood sparing techniques are acceptable in these
patients.
The risk of bleeding depends on the
extent and the type of surgery and the ability to control
bleeding and the consequence of uncontrolled bleeding.
Reduction of operative blood loss is very important to
prevent blood loss during any surgery.
- Improvement in surgical techniques
like prompt ligation of bleeding points, diathermy and local
hemostatic agents can be used.
- Use of vasoconstrictors and tourniquets
- Use of antifibrinolytic agents.
- Improved anesthetic technique like preventing episodes of
hypertension and tachycardia, avoiding hypercarbia, regional
and hypotensive anesthesia help in decreasing blood loss
during surgery.
Increasing demand and non availability
of blood has brought Blood analogues still in research
process like
- cell-free purified hemoglobulin solution
- Perfluorocarbon emulsions a inert liquid with high oxygen
solubility, oxygen delivered by simple diffusion.
- Liposome-encapsulated hemoglobin.
Auditable standards recommended by RCOG:
- Are there local protocols for the management of massive
hemorrhage in your institute in obstetrics?
- Are relevant staffs familiar with the protocol?
- Review the situation to ensure whether the communication
chain worked and no delay in providing blood products?
Thus judicious use of the optimum blood
component only when indicated, in proper dosage and
appropriate follow up studies can lead to better transfusion
practices. This also decreases the morbidity and mortality
and provides optimal patient care.
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