Transfusion medicine handbook

3. Guide to Good Transfusion Practice

3.15 Blood Administration Sets and Filters

All blood components, including platelets and plasma components, must be transfused through a standard sterile blood administration set incorporating a suitable integral screen filter (typically 170 - 260 micron pore size).

• The blood set filter is designed to trap cellular aggregates, cellular debris and clots potentially harmful to the patient.
• Microaggregate filters are not indicated.
• In New Zealand, bedside leucocyte-depleting filters are not required. All blood components undergo pre-storage leucodepletion during processing.

Blood administration sets must be used in accordance with the manufacturer’s instructions and hospital policy. The following provides a general guide to the use of blood administration sets:

A new (un-used) blood administration set, with filter, is required for all blood component transfusions.

• The set may be primed with 0.9% sodium chloride ('normal saline') or the component being transfused. If the component is selected, the set cannot be primed until the independent double-checks at the bedside are completed.
• All other solutions are incompatible as priming fluids, e.g. compound sodium lactate (Hartmann's or Ringer-Lactate), Plasmalyte in 5% glucose and dextrose solutions must not be used. The former attributed to clotting, the latter cell lysis.

The introduction of self-collapsible (closed system) intravenous (IV) infusion bags, minimised the risk of iatrogenic air embolism by self-sealing as the fluid displaces down the IV tubing. If the closed system is breached with the introduction of vents, air entry can arise. Blood components are supplied in collapsible bags and, in accordance with international guidance, blood component bags must not be vented (a warning is applied to each unit label).

• If a heath care facility has vented blood sets. Local policy should clearly define how to mitigate the risk.
• Using pressure bags for rapid infusion also carries the risk of inadvertent air-emboli and must be monitored at all times.

To minimise the risk of bacterial proliferation, each blood administration set should only be used for a maximum of 12 hours (dwell-time), or until the filter becomes clogged, adversely affecting flow rates. The maximum number of units feasible via one blood administration set can vary according to manufacturer’s guidance. As a general guide the following may be useful:

• One blood administration set may be suitable to transfuse up to 4 red cell units (2-3-hour per unit), provided the flow rate remains adequate, the filter does not clog, and the set does not exceed the maximum dwell-time of 12 hours.
• In a massive transfusion setting, where the speed of transfusion is faster, 8 - 10 units may be feasible to administer before the set is changed, provided the flow rate remains adequate, without evidence of filter clogging, and the set does not exceed the maximum dwell-time of 12 hours.

Transfuse platelets through a fresh administration set. Transfusing platelets through an administration set previously used for red cells is not recommended.

• Administration sets should be flushed with normal saline before and after platelet transfusion if the same set is to be subsequently used for the transfusion of red cells or FFP.

Fractionated products such as albumin solutions and intravenous immunoglobulin (IVIg) are supplied in glass bottles. As such a vented IV set must be used to displace the fluid down the infusion set (open IV system). Close attention is needed to ensure air emboli or fluid contamination does not arise.  A blood filter is not indicated.

At the completion of the transfusion episode, the administration set for blood components (or vented set for fractionated products), must be disconnected and replaced with a new IV infusion set, if further intravenous therapy is indicated.

• If there is doubt about the appropriateness of filters or their use, contact the NZBS Transfusion Nurse Specialist, blood bank or NZBS Transfusion Medicine Specialist/Medical Officer.