Neobook — clinical reference

Preparation of the patient

Preparation of the patient for transfusion involves documentation of informed consent. Informed consent for transfusion means a dialogue has occurred between the patient and the doctor. The significant risks, benefits and alternatives to transfusion – including the patient’s right to refuse the transfusion – should be explained in terms clearly understandable by the patient.

The length of time that consent is valid may range from a single prescription to an episode of care, or as specified by the treating institution.

As a result of this discussion, the patient should:

Understand what medical action is recommended
Be aware of the risks and benefits associated with the transfusion
Appreciate the risks and possible consequences of not receiving the recommended therapy
Understand the risks and benefits of alternatives to transfusion
Have an opportunity to ask questions
Give consent for the transfusion

The consent must be documented in a consent form or in the patient’s hospital record.

In circumstances where it is not possible to obtain informed consent before proceeding with transfusion (e.g. life-threatening emergency, comatose patient or unaccompanied minor patient), it is acceptable to proceed without consent in the patient’s best interests, provided such action is documented in the patient’s hospital record.

Identification and verification

The safe transfusion of blood products starts with the positive identification of the patient at the time of drawing a blood sample for compatibility testing. Identification is carried out by questioning the conscious patient or a suitable responsible person.

After taking the appropriate blood samples, these should be clearly labelled at the patient’s bedside, with full names, date of birth, hospital number, date of sample withdrawal and ward identification. In the case of an under-aged or unconscious patient, the medical staff may assume the responsibility for identification.

The clinician must complete a requisition form (which may be paper-based or digital), outlining all the above information plus:

Details of previous medical, obstetric and transfusion history
Diagnosis
Reason for transfusion
Number and type of component required
Date and time when the blood or blood components should be available

This information will assist the blood bank staff in identifying the recipient and in finding a compatible unit. The blood bank will return all incomplete or illegible requisition forms and improperly labelled samples. The blood service cannot accept any legal responsibility if they are not supplied with sufficient information to identify the patient.

Laboratory tests are carried out on the sample:

To determine the ABO and Rh status of the patient
To detect blood group antibodies
To test for serological compatibility with the requested component

When ordering blood for surgical procedures that only occasionally require intra-operative transfusion (fewer than 30% of cases), a group and screen request is indicated. This involves the typing of a pre-operative specimen from the patient for ABO and Rh groups and a screening test for clinically significant antibodies. Blood is then only cross-matched if clinically significant antibodies are detected or there is unexpected blood loss at surgery.

The blood component

Inspect for leaks, especially in port areas, by inverting and applying light pressure to the unit. Observe for missing port covers and abnormalities.

The colour of a red-cell concentrate unit should not be significantly darker than the attached segments. Plasma in the unit should not be murky, purple, brown or red. Platelet units will be a cloudy yellow/straw colour and should not contain grossly visible aggregates. Thawed fresh frozen plasma (FFP) will be clear, varying from yellow to straw coloured. Cryoprecipitate will usually be a cloudy straw colour.

Most acute haemolytic transfusion reactions occur as a result of errors in patient or component identification. When you are ready to start the transfusion, perform the following verification process to help ensure the correct unit will be given to the correct patient:

Recheck the physician’s order against the component received to verify you have received the correct component type
Ideally 2 qualified individuals should verify the patient and component identification at the patient’s bedside. This process involves one individual reading the information aloud from one source and the other individual comparing the information to another source (preferably done by a medical practitioner and a registered nurse or by 2 registered nurses)

Although staffing and other requirements do not always make this practicable, special care must be exercised in identification procedures. It should always be assumed that one has the wrong patient or the wrong unit, until all identification has been specifically checked.

The following guidelines should be adhered to:

All identification is carried out at the patient’s bedside
All information is read aloud by both attendants checking the blood
The recipient’s name and identification number on the unit must be identical to that on the hospital record (folder)
The identification number on the unit must correlate with the unit identification number on the requisition form and/or label
The donor’s ABO and Rh groups must be recorded on the blood unit (and the transfusion requisition form)
Compatibility between the donor and the recipient must be verified as having been confirmed
If possible, the patient’s ABO and Rh groups should be confirmed from previous transfusion records in the patient’s folder
The date and time of expiry of the unit must be checked. Expired blood must not be transfused

If any abnormalities are noted, the blood component should not be transfused. It should be returned to the hospital’s blood bank.

The patient

Asking for their full name, birth date and other relevant details identifies the patient. The questions should be phrased so that the patient gives a specific answer and not just ‘yes’ or ‘no’, e.g. ‘What are your full names?’ instead of ‘Are you Mr J Smith?’ The patient information should correlate with that on the blood unit and requisition form.

Extra care must be taken in identifying the unconscious, anaesthetised or unidentified patient by checking identity bands, written records and requisition forms. Only if all identification is in order may the transfusion be initiated.

If the patient is to receive autologous (self-donated) or directed units, these should be administered first. If a patient has both autologous and directed units available, autologous units should be given before directed units. If a patient has both directed units and nondirected units available, directed units should be given before non-directed units.

Aseptic technique

Blood is usually transfused through a large needle or cannula, the size of which is selected according to the calibre of the patient’s veins. Almost any peripheral vein is suitable for transfusion, but the forearm veins are preferable as the patient’s movement will not be restricted.

Meticulous skin care and aseptic techniques cannot be over emphasised in transfusion therapy, as blood acts as an ideal culture medium for bacterial growth. The proposed site for venepuncture should be cleaned with the recommended hospital antiseptic, working from clean to dirty areas. Ideally, gloves and a sterile field should always be used to position the cannulae for transfusion, but most especially in immunocompromised or long-term transfusion patients. The site should never be re-palpated after cleansing.

During transfusion, the transfusion site should be visible through a transparent dressing so that any inflammation or infiltration may be seen immediately. The transfusion cannula should be repositioned if inflammation or infiltration is observed.

Monitoring the patient

A critical part of transfusion therapy is the monitoring of the patient, whether by a nurse or a medical practitioner. The accurate and quick interpretation of adverse effects could prevent a fatal reaction. The unit number, the date of transfusion and the starting and finishing time of each unit transfused should be recorded in the patient’s folder. Some services require additional signatures on accompanying forms. All this information should be permanently retained in the patient’s folder.

Baseline observations of vital signs should be recorded prior to commencing the transfusion. The patient is then observed closely for the first 30 minutes of the transfusion to detect any untoward reaction, and to ensure that the desired rate of transfusion is maintained.

In cases of major blood loss, ideally the central venous pressure (CVP), pulse, blood pressure (BP), respiratory rate and urinary output should be monitored every 15 minutes throughout the transfusion. In less severe cases, the recipient’s vital signs should be checked every half hour after the initial 30-minute observation. Patients at risk for circulatory overload should be observed for 12 – 24 hours after transfusion.

If a transfusion reaction is suspected because the patient complains of symptoms or there are clinically significant changes in vital-sign measurements:

The transfusion must be stopped immediately
The drip set must be changed
The vein must be kept open with a transfusion of normal saline

The following actions must then be undertaken:

A member of the medical staff must be contacted immediately
The patient’s temperature, pulse, respiratory rate and BP must be recorded
All clerical and identity checks must be repeated

Further management depends on the type and severity of the reaction.

All empty blood units should be returned to the blood bank, where they must be retained for 48 hours following transfusion, at a temperature of 1 °C – 6 °C.

Special precautions

Rate of transfusion

The rate of the transfusion depends on the clinical condition of the patient. A patient in acute shock from massive blood loss will require rapid transfusion, whereas the rate should not exceed 2 ml per minute in a patient with chronic anaemia. A relatively slow rate of 5 ml per minute is recommended for the first 30 minutes and, if there is no sign of untoward reaction, the rate can then be increased.

Blood transfusions must be completed within 6 hours of entry of the pack. Blood components that are not used immediately should be stored at the temperature specified by the blood bank. Blood components that are no longer required for a specific patient must be returned to the blood bank, either for correct storage (only if still contained in the original “hamper” packaging with no seals broken) or for disposal.

Filters

Red blood cells (RBCs), whole blood, cryoprecipitate and FFP are administered through a standard blood-recipient set or Y-type giving set. These sets have 170 μm – 240 μm mesh filters to prevent the transfusion of clots or coagulation debris. The filter should be covered with blood to ensure that the full filtering area is used.

A platelet-administration set should preferably be used for platelets, although the standard filter-administration set may also be used in an emergency. The latter results in greater loss of the available platelets due to a larger surface area for adhesion.
The use of microaggregate (40 μm) filters is not recommended.

The administration set should be changed:

When there is a transfusion reaction, in order to prevent further potentially harmful blood entering the patient’s system
Between red cells and other blood products, and between red cell transfusions of different ABO groups
Before infusing other fluids, e.g. dextran, Ringers lactate
Every 12 – 24 hours in patients requiring long-term transfusion

Temperature of the blood

If cold blood is administered at a slow rate, it does not appear to affect the circulatory system. However, in cases where rapid transfusion is necessary, complications such as cardiac arrhythmias can be avoided by warming the blood to not >37 °C. Overheating of the blood can cause extensive haemolysis with renal damage and possible death.

Blood should be warmed with a blood warmer specifically designed for this purpose. This apparatus should be equipped with a visible temperature-monitoring device and should have an audible alarm.

The practice of warming blood in a sink of warm water is ineffectual, as only the outer red cell layers are warmed. It may also present an infectious hazard as the ports may become contaminated. Furthermore, overheating may result in devastating haemolysis of the blood product, with potentially fatal consequences.

Under no circumstances should blood be heated in a microwave oven or similar device. This not only results in extensive haemolysis, but also causes conformational changes and denaturation of proteins.

Blood warming is not routinely indicated and refrigerated blood may be transfused over several hours without harm.

Indications for warming are:

Massive transfusion of >50 ml/kg/h
Infants transfused at >15 ml/kg/h
Neonates receiving exchange transfusion or large-volume transfusion
Patients with high-titre cold haemagglutinins reactive in vitro at temperatures above 30 °C
Transfusion of blood products through central lines
Hypothermia

Additives

No medications or other fluid should be added to the blood or blood products before or during a transfusion because:

Bacterial contamination is a real hazard whenever any unit of blood is entered
A reaction could occur between the drug and the anticoagulant or nutrient fluid in the blood, e.g. dextrose solutions might cause lysis or aggregation of the red cells in the transfusion set
Therapeutic levels of a drug may not be achieved if the blood is administered slowly

If it is difficult to infuse medication through an alternative access site, then a Y-piece may be inserted near the junction of the insertion of the intravenous (IV) transfusion cannula.

The only fluids that can be given concurrently through the same IV device as a red cell transfusion are:

Normal saline
Calcium-free balanced salt solutions, e.g. Plasmalyte-L, Plasmalyte-B, Balsol, modified Ringer’s lactate
4% albumin
Plasma protein fractions
ABO-compatible plasma

Ordering and Administration of Blood