Untoward effects associated with administration of sodium bicarbonate during massive blood transfusion include each of the following EXCEPT:

Untoward effects associated with administration of sodium bicarbonate during massive blood transfusion include each of the following EXCEPT:

• A. Hyperosmolality
• B. Paradoxical cerebrospinal fluid acidosis
• C. Hypercarbia
• D. Hyperkalemia

Answer: (D)

The key idea is that giving sodium bicarbonate during massive transfusion can produce effects related to the added sodium load and CO2 generation, not increases in potassium. Bicarbonate raises plasma osmolality because of the extra sodium and bicarbonate, leading to potential osmotic shifts (hyperosmolality). As bicarbonate neutralizes hydrogen ions, CO2 is produced; CO2 readily crosses into the cerebrospinal fluid, where it can lower CSF pH, causing paradoxical cerebrospinal fluid acidosis even though the blood pH is rising. The CO2 from the reaction can also accumulate if ventilation isn’t sufficient, resulting in hypercarbia. Potassium, however, tends to move into cells when alkalemia is produced, which lowers serum potassium rather than raising it; thus hyperkalemia is not an expected effect of bicarbonate administration in this setting. In massive transfusion, hyperkalemia is more often a consequence of potassium leakage from stored blood, making it the exception here.

The key idea is that giving sodium bicarbonate during massive transfusion can produce effects related to the added sodium load and CO2 generation, not increases in potassium. Bicarbonate raises plasma osmolality because of the extra sodium and bicarbonate, leading to potential osmotic shifts (hyperosmolality). As bicarbonate neutralizes hydrogen ions, CO2 is produced; CO2 readily crosses into the cerebrospinal fluid, where it can lower CSF pH, causing paradoxical cerebrospinal fluid acidosis even though the blood pH is rising. The CO2 from the reaction can also accumulate if ventilation isn’t sufficient, resulting in hypercarbia. Potassium, however, tends to move into cells when alkalemia is produced, which lowers serum potassium rather than raising it; thus hyperkalemia is not an expected effect of bicarbonate administration in this setting. In massive transfusion, hyperkalemia is more often a consequence of potassium leakage from stored blood, making it the exception here.