Dextran is added to collected blood:

Appeared in: AIIMS Delhi NO-2016

Explanation

The question contains a likely typo; it should refer to 'Dextrose', not 'Dextran'.
Dextrose is a simple sugar (glucose) that acts as the primary energy source for red blood cells (RBCs) during storage.
This energy, produced via glycolysis, is essential for maintaining the RBC's membrane integrity and metabolic functions, thus prolonging its viability and shelf life.
Standard preservative solutions like CPDA-1 (Citrate-Phosphate-Dextrose-Adenine) include dextrose for this specific purpose.

Option A: Preventing coagulation is the function of Citrate, which binds to calcium ions, an essential component of the clotting cascade.
Option C: Maintaining a stable pH and preventing the blood from becoming too acidic during storage is the role of the Phosphate buffer.
Option D: This is fundamentally incorrect and unsafe. Blood products are collected and stored under sterile conditions to prevent bacterial growth, which would cause sepsis if transfused.

Clinical Relevance

Nursing practice connection: Knowing Function of additives in blood collection bags helps nurses interpret findings accurately and avoid errors in routine assessment, medication administration, and patient teaching.
Understanding the role of each component in blood preservation is critical for nurses to ensure the safety and efficacy of blood transfusions.
Administering blood that has been improperly stored can lead to transfusion reactions, hemolysis, and lack of therapeutic effect.
What if? If a blood bag did not contain Dextrose, the RBCs would rapidly deplete their energy stores, leading to cell death (hemolysis) and making the unit unsuitable for transfusion long before its expiration date.

How to Approach the Question

First, identify the core topic of the question, which is the purpose of additives in collected blood.
Recognize that 'Dextran' is a common typo in exam questions and the intended substance is likely 'Dextrose', which is a standard component of blood preservatives.
Recall the primary functions of the main additives in solutions like CPD or CPDA-1.
Evaluate the options: 'To prolong the RBC life' directly matches the function of Dextrose as an energy source.
Systematically eliminate the other options by correctly assigning their functions: preventing coagulation (Citrate), maintaining pH (Phosphate), and noting that promoting microbial growth is always incorrect.
Confirm the choice by remembering that Dextran is a plasma expander, not an RBC preservative.

Concept Tested & Keywords

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E6 Pharmacology Nursing Lilley 11e Part 2 p. 163-165

E6 Pharmacology KD Tripathi Essentials 9e Part 2 p. 307-309

E6 Physiology Guyton 4SAE Part 2A p. 31-33

Practise the full AIIMS Delhi NO-2016

Attempt every question from this paper in a timed mock, then review the full solution for each one.