Blood components must be filtered at the time of transfusion to remove clots and small accumulations of platelets and white blood cells that form during collection and storage. Standard transfusion kits contain filters ranging in size from 170 to 260 microns. Smaller kits are also available with built-in filters for plasma, platelets and red cell aliquots.
The manufacturer provides instructions for use on the packaging of the transfusion device. Blood sets should not be integrated into other lines if this can be avoided. In case they are provided with a copy, the injection port closest to the IV line and the primary IV line should be used. Direct type kits are directly loaded with the blood component. Y-type devices can be filled with blood or saline. Usually a new set is poured for each component. If necessary, test 2 units compatible with each other: one set can be used for both blood and solution, provided that the substances are administered within 4 hours.
Needles and catheters
The size of the needle depends on the integrity and width of the patient’s vein. An 18-gauge needle is standard, but the doctor can use both a needle and a 23-mm catheter for transfusion. The smaller the caliber, the slower the flow and the higher the risk of clotting. Care must be taken to avoid excessive pressure and consequent hemolysis when very narrow devices are used.
Leukocyte removal filters
Special filters can be provided by the transfusion service when erythrocytes or platelets that do not contain leukocyte impurities are not available. RBC and platelet filters do not use the same technology to remove white blood cells and are not interchangeable. Some are designed to be attached to standard infusion sets. Most WBC filters are for gravity drop applications and have special installation requirements, so all manufacturer’s instructions should be checked before use.
Pumps
Mechanical pumps can be useful in controlling the very slow transfusion rates required by neonatal and pediatric patients, but special care is required to prevent hemolysis. Only pumps specifically designed for transfusion should be used. Some of them can interact with standard infusion sets, others need to be provided.
Pressure bags are only needed in emergencies when blood needs to be transfused quickly, such as 5 minutes per unit. The bag is only inflated until the flow of blood through the drip chamber is continuous (about 200 mm/Hg).
Blood warmers
To prevent cardiac arrhythmia associated with the rapid infusion of large volumes of cold blood, blood warmers are used under the following conditions:
- adults receiving blood at a rate exceeding 100 ml per minute;
- children receiving blood more than 15 ml / kg / hour;
- patients with clinically significant cold agglutinins;
- rapid transfusion of blood through the central lines.
Blood should not be heated to a temperature that causes hemolysis. Only supervised linear devices are acceptable for use, some of them require special software. The mud heater should have a visible thermometer and, ideally, an audible alarm. The heater is adjusted according to the manufacturer’s instructions and the temperature should be checked periodically during extended use.
Permits and drugs
Normal saline solution (0,9% sodium chloride) is allowed to be added to the blood (drugs and drugs should never be administered). Compatible plasma or 5% albumin can be injected into the blood after the doctor’s approval. Isotonic electrolyte solutions, which do not contain calcium, may be mixed with blood if the treating physician approves the decision for such use or if appropriate safety documentation is available.
Solutions containing glucose (eg, 5% dextrose) can lead to hemolysis of red blood cells, and those containing calcium (eg, Ringer’s lactate) can cause dangerous blood clots.
Packaged RBCs are sometimes diluted with 0,9% NaCl to reduce viscosity and improve flow.
AdSol devices usually do not require additional mixing as they already contain preservatives. RBCs should be infused through an IV catheter and standard 170 micron filter at a rate of 2 ml/min for the first 15 minutes. It is important to observe confirmation of the transfusion reaction during this time period. If no side effects occur, the rate may be increased to 4 ml/min for rapid transfusions. A transfusion with rates of 17 ml / min allows you to remove the entire unit of blood in 30 minutes.
The usual recommended period is 1,5 to 2 hours per unit. The maximum time allowed for infusion of one unit of blood varies in the range of 4 hours. In emergency situations, the rate of transfusion can be adjusted by the attending physician. Infusion rates above 60 ml/min are dangerous, and rates over 100 ml/min can cause cardiac arrest.
External pressure devices are used to increase the effectiveness of the procedure. BP should not exceed 300 mm/Hg. It is important to monitor the performance of the blood pressure cuffs because they have an uneven distribution and can cause leakage.
Platelets are poured through special filters at a speed that allows you to transfuse a pool of random donor data of substances or one platelet within 30-60 minutes. RBCs are usually expelled through a standard blood filter at a rate of 30 to 60 minutes per bag.
Cryoprecipitate is transfused through a conventional blood device at a rate of 4 to 10 ml/min (at this rate, a pool of 30 packets can be administered for 10 minutes).