Stored blood as compared to fresh blood has: September 2012
**Stored Blood Compared to Fresh Blood**
**Core Concept**
The storage of blood involves maintaining the viability of red blood cells (RBCs) by controlling the storage conditions, such as temperature, pH, and the presence of additives. The primary goal is to preserve the functional integrity of RBCs, including their ability to transport oxygen.
**Why the Correct Answer is Right**
During storage, RBCs undergo a process called glycolytic metabolism, where they break down glucose to produce energy. However, this process leads to the accumulation of lactic acid, which decreases the pH of the stored blood. As a result, the stored blood has a lower pH (more acidic) compared to fresh blood. This decrease in pH can lead to the loss of RBC membrane integrity, making the stored blood less effective for transfusion.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because it does not accurately describe the change in pH of stored blood. While it is true that stored blood has a lower pH, this option does not address the underlying cause of this change.
**Option B:** This option is incorrect because it does not accurately describe the change in pH of stored blood. The addition of preservatives, such as citrate and dextrose, actually helps to maintain the pH of stored blood, rather than decreasing it.
**Option C:** This option is incorrect because it does not accurately describe the change in pH of stored blood. The breakdown of glucose during storage leads to the accumulation of lactic acid, which decreases the pH of the stored blood, rather than increasing it.
**Clinical Pearl / High-Yield Fact**
When transfusing stored blood, it is essential to monitor the recipient's pH levels and adjust the transfusion rate accordingly to prevent acid-base imbalances.
**Correct Answer:** A. Decreased pH