Fresh citrated blood: composition and proportions
Fresh citrated blood is a full-fledged transfusion medium prepared for the most rapid possible transfusion to the patient. The main obstacle in any blood preparation is its natural tendency to coagulate.
The main stabilizer used here is a 6% sodium citrate solution. It is important to understand that neither sodium chloride, calcium gluconate, nor sodium heparin is suitable for this purpose.
During preparation, the following ratio is strictly observed:
- Stabilizer : Blood = 1:10.
This medium is not intended for prolonged storage in a blood bank. Its clinical use is justified either immediately after the preparation procedure or within the next few hours (this usage regimen in surgery is designated by the Latin term ex tempore).
Heparinized blood: specifics of application
The second important blood transfusion medium is heparinized blood. Its purpose is highly specific: it is used for the initial priming of cardiopulmonary bypass (CPB) circuits before major cardiac surgery.
Note the strict limitations: this medium is used specifically for cardiopulmonary bypass; it is not used to prime the circuits of mechanical ventilation machines, extracorporeal membrane oxygenation (ECMO) systems, or hemodialysis machines ("artificial kidney").
The composition of the preservative solution in this case is more complex:
- Sodium heparin acts as the basic stabilizer and preservative.
- Dextrose provides energy support for cellular elements.
- Chloramphenicol is added to prevent bacterial contamination.
Storage conditions and shelf life
While fresh citrated blood is transfused almost immediately (ex tempore), heparinized blood requires specific temperature conditions.
The prepared heparinized medium must be stored in refrigeration equipment with strict temperature maintenance at 4 °C. At the same time, its shelf life is extremely limited and is exactly 24 hours. After this time, using this solution for work with a cardiopulmonary bypass machine is strictly prohibited.
Briefly: answers to topical questions
What is the exact shelf life of fresh citrated blood in hours?
Fresh citrated blood is used immediately after preparation or within the next few hours (ex tempore). The exact shelf life in hours is not specified in the provided guidelines.
What other donor blood transfusion media exist besides fresh citrated and heparinized blood?
In addition to fresh citrated and heparinized blood, the main donor blood transfusion media include stored whole blood and red blood cell suspension. Stored whole blood is prepared using special solutions with added antibiotics, while red blood cell suspension is a mixture of red blood cell mass and a preservative solution in equal proportions.
What preservative solutions are used for the long-term storage of whole donor blood?
For the long-term storage of whole donor blood, special preservative solutions are used containing a stabilizer (sodium citrate) and preservatives such as dextrose and sucrose. Depending on the solution composition, shelf lives are:
- Glugicir solution — 21 days.
- Ciglyufad solution — 35 days.
To remember the proportion for fresh citrated blood, imagine a "10 out of 10" rating — 1 part stabilizer is needed for 10 parts blood (1:10).
Class and exam questions
What solution is used as a stabilizer for fresh citrated blood?
A 6% sodium citrate solution is used as a stabilizer.
In what ratio are blood and stabilizer mixed during the preparation of fresh citrated blood?
The proportion is 1 part stabilizer to 10 parts blood (1:10).
What specifically is heparinized blood used for?
It is intended for priming the circuits of cardiopulmonary bypass (CPB) machines.
What is the composition of the preservative in heparinized blood?
Its composition includes sodium heparin, dextrose, and chloramphenicol.
What else to study on this topic
- Mechanism of action of sodium citrate on blood coagulation factors
- Principles of operation of the cardiopulmonary bypass (CPB) machine
- Pharmacodynamics of sodium heparin in transfusiology
- Reasons for limiting the shelf life of heparinized blood to 24 hours
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