Clinical use of blood, blood products and replacement fluid

Obstetric care may require blood transfusions. It is important to use blood, blood products and replacement fluids appropriately and to be aware of the principles designed to assist health workers in deciding when (and when not) to transfuse.

The appropriate use of blood products is defined as the transfusion of safe blood products to treat a condition leading to significant morbidity or mortality that cannot be prevented or managed effectively by other means.

Conditions that may require blood transfusion include:

• postpartum haemorrhage leading to shock;

• loss of a large volume of blood at operative delivery;

• severe anaemia, especially in later pregnancy or if accompanied by cardiac failure.

Note: For anaemia in early pregnancy, treat the cause of anaemia and provide haematinics.

District hospitals should be prepared for the urgent need for blood transfusion. It is mandatory for obstetric units to keep stored blood available, especially type O negative blood and fresh frozen plasma, as these can be life-saving.

UNNECESSARY USE OF BLOOD PRODUCTS

Used correctly, blood transfusion can save lives and improve health. As with any therapeutic intervention it may, however, result in acute or delayed complications and it carries the risk of transmission of infectious agents. It is also expensive and uses scarce resources.

• Transfusion is often unnecessary because:

- Conditions that may eventually require transfusion can often be prevented by early treatment or prevention programmes.

- Transfusions of whole blood, red cells or plasma are often given to prepare a woman quickly for planned surgery, or to allow earlier discharge from the hospital. Other treatments, such as the infusion of IV fluids, are often cheaper, safer and equally effective

• Unnecessary transfusion can:

- expose the woman to unnecessary risks;

- cause a shortage of blood products for women in real need. Blood is an expensive, scarce resource.

RISKS OF TRANSFUSION

Before prescribing blood or blood products for a woman, it is essential to consider the risks of transfusing against the risks of not transfusing.

Whole blood or red cell transfusion

• The transfusion of red cell products carries a risk of incompatible transfusion and serious haemolytic transfusion reactions.

• Blood products can transmit infectious agents—including HIV, hepatitis B, hepatitis C, syphilis, malaria and Chagas disease—to the recipient.

• Any blood product can become bacterially contaminated and very dangerous if it is manufactured or stored incorrectly.

Plasma transfusion

• Plasma can transmit most of the infections present in whole blood.

• Plasma can also cause transfusion reactions. 

• There are very few clear indications for plasma transfusion (e.g. coagulopathy) and the risks very often outweigh any possible benefit to the woman.

Blood safety

• The risks associated with transfusion can be reduced by:

- effective blood donor selection, deferral and exclusion;

- screening for transfusion-transmissible infections in the blood donor population (e.g. HIV/AIDS and hepatitis);

- quality assurance programmes;

- high quality blood grouping, compatibility testing, component separation and storage and transportation of blood products;

- appropriate clinical use of blood and blood products.

SCREENING FOR INFECTIOUS AGENTS

• Every unit of donated blood should be screened for transfusion-transmissible infections using the most appropriate and effective tests, in accordance with both national policies and the prevalence of infectious agents in the potential blood donor population.

• All donated blood should be screened for the following:

- HIV-1 and HIV-2;

- Hepatitis B surface antigen (HBsAg);

- Treponema pallidum antibody (syphilis).

• Where possible, all donated blood should also be screened for:

- Hepatitis C;

- Chagas disease, in countries where the seroprevalence is significant;

- Malaria, in low-prevalence countries when donors have travelled to malarial areas. In areas with a high prevalence of malaria, blood transfusion should be accompanied by  prophylactic antimalarials.

• No blood or blood product should be released for transfusion until all nationally required tests are shown to be negative. 

• Perform compatibility tests on all blood components transfused even if, in life-threatening emergencies, the tests are performed after the blood products have been issued.

PRINCIPLES OF CLINICAL TRANSFUSION

The fundamental principle of the appropriate use of blood or blood product is that transfusion is only one element of the woman’s management. When there is sudden rapid loss of blood due to haemorrhage, surgery or complications of childbirth, the most urgent need is usually the rapid replacement of the fluid lost from circulation. 

Transfusion of red cells may also be vital to restore the oxygen-carrying capacity of the blood.

Minimize “wastage” of a woman’s blood (to reduce the need for transfusion) by:

• using replacement fluids for resuscitation;

• minimizing the blood taken for laboratory use;

• using the best anaesthetic and surgical techniques to minimize blood loss during surgery;

• salvaging and reinfusing surgical blood lost during procedures (autotransfusion), where appropriate

Principles to remember:

• Transfusion is only one element of managing a woman.

• Decisions about prescribing a transfusion should be based on national guidelines on the clinical use of blood, taking the woman’s needs into account.

• Blood loss should be minimized to reduce the woman’s need for transfusion.

• The woman with acute blood loss should receive effective resuscitation (IV replacement fluids, oxygen, etc.) while the need for transfusion is being assessed.

• The woman’s haemoglobin value, although important, should not be the sole deciding factor in starting the transfusion. The decision to transfuse should be supported by the need to relieve clinical signs and symptoms and prevent significant morbidity and mortality.

• The clinician should be aware of the risks of transfusion-transmissible infection in blood products that are available.

• Transfusion should be prescribed only when the benefits to the woman are likely to outweigh the risks.

• A trained person should monitor the transfused woman and respond immediately if any adverse effects occur

• The clinician should record the reason for transfusion and investigate any adverse effects

PRESCRIBING BLOOD

Prescribing decisions should be based on national guidelines on the clinical use of blood, taking the woman’s needs into account. 

• Before prescribing blood or blood products for a woman, keep in mind the following: 

- expected improvement in the woman’s clinical condition;

- methods to minimize blood loss to reduce the woman’s need for transfusion;

- alternative treatments that may be given, including IV replacement fluids or oxygen, before making the decision to transfuse;

- specific clinical or laboratory indications for transfusion;

- risks of transmitting HIV, hepatitis, syphilis or other infectious agents through the blood products that are available;

- benefits of transfusion versus risk for the particular woman;

- other treatment options if blood is not available in time;

- need for a trained person to monitor the woman and immediately respond if a transfusion reaction occurs.

• Finally, if in doubt, ask yourself the following question:

- If this blood was for myself or my child, would I accept the transfusion in these circumstances?

MONITORING THE TRANSFUSED WOMAN

For each unit of blood transfused, monitor the woman at the following stages:

• before starting the transfusion;

• at the onset of the transfusion;

• 15 minutes after starting the transfusion;

• at least every hour during the transfusion;

• at 4 hour intervals after completing the transfusion.

Closely monitor the woman during the first 15 minutes of the transfusion and regularly thereafter to detect early symptoms and signs of adverse effects. 

At each of these stages, record the following information on the woman’s chart:

• general appearance;

• temperature;

• pulse;

• blood pressure;

• respiration;

• fluid balance (oral and IV fluid intake, urinary output).

In addition, record:

• the time the transfusion is started;

• the time the transfusion is completed;

• the volume and type of all products transfused;

• the unique donation numbers of all products transfused; 

• any adverse effects.

RESPONDING TO A TRANSFUSION REACTION

Transfusion reactions may range from a minor skin rash to anaphylactic shock. Stop the transfusion and keep the IV line open with IV fluids (normal saline or Ringer’s lactate) while making an initial assessment of the acute transfusion reaction and seeking advice. If the reaction is minor, give promethazine 10 mg by mouth and observe.

Managing anaphylactic shock from mismatched blood transfusion

• Manage as for shock and give:

- adrenaline 1:1 000 solution (0.1 mL in 10 mL IV normal saline or Ringer’s lactate) IV slowly;

- promethazine 10 mg IV;

- hydrocortisone 1 g IV every 2 hours as needed.

• If bronchospasm occurs, give aminophylline 250 mg in normal saline or Ringer’s lactate 10 mL IV slowly.

• Combine resuscitation measures above until stabilized.

• Monitor renal, pulmonary and cardiovascular functions.

• Transfer to referral centre when stable.

Documenting a transfusion reaction

• Immediately after the reaction occurs, take the following samples and send with a request form to the blood bank for laboratory investigations.

- immediate post-transfusion blood samples:

- 1 clotted; 

- 1 anticoagulated (EDTA/sequestrene) from the vein opposite the infusion site;

- the blood unit and giving set containing red cell and plasma residues from the transfused donor blood;

- the first specimen of the woman’s urine following the reaction.

• If septic shock is suspected due to a contaminated blood unit, take a blood culture in a special blood culture bottle.

• Complete a transfusion reaction report form.

• After the initial investigation of the transfusion reaction, send the following to the blood bank for laboratory investigations:

- blood samples at 12 hours and 24 hours after the start of the reaction:

- 1 clotted;

- 1 anticoagulated (EDTA/sequestrene) taken from the vein opposite the infusion site;

- all urine for at least 24 hours after the start of the reaction.

• Immediately report all acute transfusion reactions, with the exception of mild skin rashes, to a medical officer and to the blood bank that supplied the blood.

• Record the following information on the woman’s chart:

- type of transfusion reaction;

- length of time after the start of transfusion that the reaction occurred;

- volume and type of blood products transfused;

- unique donation numbers of all products transfused.

REPLACEMENT FLUIDS: SIMPLE ALTERNATIVES TO TRANSFUSION

Only normal saline (sodium chloride 0.9%) or balanced salt solutions that have a similar concentration of sodium to plasma are effective replacement fluids. These should be available in all hospitals where IV replacement fluids are used.

Replacement fluids are used to replace abnormal losses of blood, plasma or other extracellular fluids by increasing the volume of the vascular compartment. They are used principally in: 

• management of women with established hypovolaemia (e.g. haemorrhagic shock);

• maintenance of normovolaemia in women with on-going fluid losses (e.g. surgical blood loss).

INTRAVENOUS REPLACEMENT THERAPY

Intravenous replacement fluids are first-line treatment for hypovolaemia. Initial treatment with these fluids may be life-saving and can provide some time to control bleeding and obtain blood for transfusion if it becomes necessary.

Crystalloid fluids

• Crystalloid replacement fluids: 

- contain a similar concentration of sodium to plasma;

- cannot enter cells because the cell membrane is impermeable to sodium;

- pass from the vascular compartment to the extracellular space (normally only a quarter of the volume of crystalloid infused remains in the vascular compartment) compartment. 

• To restore circulating blood volume (intravascular volume), infuse crystalloids in a volume at least three times the volume lost.

Dextrose (glucose) solutions are poor replacement fluids. Do not use them to treat hypovolaemia unless there is no other alternative. 

Colloid Fluids

• Colloid solutions are composed of a suspension of particles that are larger than crystalloids. Colloids tend to remain in the blood where they mimic plasma proteins to maintain or raise the colloid osmotic pressure of blood.

• Colloids are usually given in a volume equal to the blood volume lost. In many conditions where the capillary permeability is increased (e.g. trauma, sepsis), leakage out of the circulation will occur and additional infusions will be necessary to maintain blood volume.

Points to remember:

• There is no evidence that colloid solutions (albumin, dextrans, gelatins, hydroxyethyl starch solutions) have advantages over normal saline or balanced salt solutions for resuscitation.

• There is evidence that colloid solutions may have an adverse effect on survival.

• Colloid solutions are much more expensive than normal saline and balanced salt solutions.

• Human plasma should not be used as a replacement fluid. All forms of plasma carry a similar risk as whole blood of transmitting infection, such as HIV and hepatitis.

• Plain water should never be infused intravenously. It will cause haemolysis and will probably be fatal.

There is a very limited role for colloids in resuscitation. 

Safety

Before giving any IV infusion:

• check that the seal of the infusion bottle or bag is not broken;

• check the expiry date;

• check that the solution is clear and free from visible particles.

Maintenance fluid therapy

Maintenance fluids are crystalloid solutions, such as dextrose or dextrose in normal saline, used to replace normal physiological losses through skin, lungs, faeces and urine. If it is anticipated that the woman will receive IV fluids for 48 hours or more, infuse a balanced electrolyte solution (e.g. potassium chloride 1.5 g in 1 L IV fluids) with dextrose. The volume of maintenance fluids required by a woman will vary, particularly if the woman has fever or with high ambient temperature or humidity, when losses will increase.

Other routes of fluid administration

There are other routes of fluid administration in addition to the IV route.

Oral and nasogastric administration

• This route can often be used for women who are mildly hypovolaemic and for women who can receive oral fluids.

• Oral and nasogastric administration should not be used if:

- the woman is severely hypovolaemic;

- the woman is unconscious;

- there are gastrointestinal lesions or reduced gut motility (e.g. obstruction);

- imminent surgery with general anaesthesia is planned.

Rectal administration

• Rectal administration of fluids is not suitable for severely hypovolaemic women.

• Advantages of rectal administration include: 

- It allows the ready absorption of fluids.

- Absorption ceases and fluids are ejected when hydration is complete.

- It is administered through a plastic or rubber enema tube inserted into the rectum and connected to a bag or bottle of fluid.

- The fluid rate can be controlled by using an IV set, if necessary.

- The fluids do not have to be sterile. A safe and effective solution for rectal rehydration is 1 L of clean drinking water to which a teaspoon of table salt is added.

Subcutaneous administration

• Subcutaneous administration can occasionally be used when other routes of administration are unavailable but is unsuitable for severely hypovolaemic women. 

• Sterile fluids are administered through a cannula or needle inserted into the subcutaneous tissue (the abdominal wall is a preferred site).

Solutions containing dextrose can cause tissue to die and should not be given subcutaneously.

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