Mandatory checks before hemotransfusion
Even if an individually matched red blood cell suspension has been delivered to the ward, the attending physician is not authorized to start the infusion immediately. There is a strict protocol for final verification. Before the blood enters the patient's vein, three mandatory steps must be performed:
- Control determination of the blood group and Rh factor directly from the bottle or plastic bag.
- Performing a group compatibility test (using the AB0 system).
- Performing an Rh compatibility test.
Transfusion is permitted exclusively when the blood group and Rh type match completely, and there are no visual signs of agglutination in all performed compatibility tests.
Transfusion set design
A specialized single-use plastic set, supplied in a sterile polyethylene bag, is used for the procedure. Its main design feature is the presence of a built-in nylon filter that reliably prevents blood clots and thrombi from entering the patient's bloodstream.
The standard set includes:
- A short tube with a needle and an air filter. It serves to admit air into the bottle ("air vent"), ensuring an even flow of fluid.
- A long tube equipped with two needles. One needle is designed to puncture the blood container, and the second is for puncturing the patient's vein.
- A drip chamber containing a nylon barrier inside.
- A roller clamp, which the physician uses to smoothly regulate the infusion rate.
- A connecting tube and protective needle caps.
Sets can be single or feature a Y-shaped connection for alternate transfusions from different bottles.
Algorithm for transfusion from a plastic bag (hemacon)
A plastic bag is the most common container for blood components. Preparation of the set includes the following stages:
- Preparation and opening: Gently mix the blood in the bag. A hemostatic clamp is applied to the central outlet tube, after which the tube is cut 1–1.5 cm below the clamp.
- Assembly: The cap is removed from the set's cannula, and it is tightly connected to the cut tube of the bag.
- Air removal: The bag is hung upside down on a stand. The set is lifted and the drip chamber is inverted so that the nylon filter is on top. The roller clamp is released, the drip chamber is filled with blood halfway, and then the clamp is closed again.
- Priming the tubing: The drip chamber is returned to its original position (filter at the bottom, immersed in fluid). The clamp is opened and the lower part of the long tube is filled until air is completely expelled (until a drop appears from the needle).
- Final stage: A few drops are released from the needle onto a white tile to perform compatibility tests. The physician visually verifies that there are no air bubbles in the set, and then adjusts the infusion rate using the clamp.
If it is necessary to change the bag, the set is closed with the roller clamp, a hemostatic clamp is applied to the tube of the empty hemacon, the empty container is disconnected, and a new one is connected.
Specifics of working with a standard glass bottle
If blood is supplied in a glass bottle, the algorithm changes slightly during the container preparation stage:
- Processing: The aluminum cap is removed from the bottle. The exposed rubber stopper is thoroughly treated with alcohol or a 10% iodine alcohol solution.
- Puncture: The stopper is pierced with two needles simultaneously. The short air tube is connected to the first needle (its free end is fixed to the stand above the bottom of the bottle). The main transfusion set is connected to the second needle.
- Priming: The bottle is inverted upside down on the stand. Further filling of the drip chamber and air expulsion are carried out in the exact same way as when working with a plastic bag.
Connecting to the patient
Direct connection of the set to the patient's body is carried out strictly after the set is fully assembled, the tubes are filled with blood without a single air bubble, and the group and Rh compatibility tests have been successfully completed.
Execution Technique:
- If the patient's vein has already been punctured previously (e.g., for administering blood substitute solutions), the transfusion set is simply connected to the already established needle or catheter.
- If there is no permanent venous access, the medical worker punctures the vein and immediately connects the prepared and primed set to it.
To correctly fill the drip chamber without bubbles, remember the inversion rule: "First, filter on top — fill halfway; then, filter on the bottom — bleed out air until a drop appears."
Class and exam questions
Can blood be poured into an intermediate container before administration?
No, the basic rule of transfusiology states that transfusion must be carried out strictly from the same container (bottle or bag) in which the blood was originally stored.
When exactly is the set connected to the patient?
Connection is performed exclusively after the complete removal of air from all tubes of the set and the successful completion of control compatibility tests for AB0 and Rh systems.
Why is a short tube with a needle used in the set when working with bottles?
The short tube ("air vent") is necessary for air to enter the rigid glass bottle. This allows the blood to flow freely into the set under the influence of gravity. The end of the tube is fixed above the level of the bottom of the bottle.
What else to study on this topic
- Technique for performing the AB0 group compatibility test
- Algorithm for performing the Rh compatibility test
- Signs of agglutination during tile tests
- Specifics of using Y-shaped sets for transfusion from different bottles
- Physician's actions upon detecting air bubbles in the set after priming it
Master the entire topic in the "General Surgery" course
This is a summary. The course covers everything tested in classes and exams.
- Complete manual on the "Blood transfusion algorithm" and 3,335 more subject pages
- Assignments and quizzes after every topic — just like in a colloquium
- AI tutor answers questions on the topic anytime
- 70 video lessons on the subject
Other topics in the section "CHAPTER 6. BLOOD TRANSFUSION"
Prepared by WhiteCoat Pro faculty in accordance with the medical school curriculum. For educational purposes only.