An, 8 year old boy, weighing 30kg is undergoing resection of wilms tumor. His hemoglobin is 12g/dL. If the threshold for transfusion is 8g/dL, the allowable blood loss is
**Core Concept**
The allowable blood loss during surgery can be calculated using the formula: Allowable Blood Loss (ABL) = (Initial Hemoglobin - Threshold Hemoglobin) x Weight in kg. This formula is used to determine the maximum amount of blood that can be lost during surgery without requiring a transfusion.
**Why the Correct Answer is Right**
To calculate the allowable blood loss, we first need to determine the threshold hemoglobin level, which is 8g/dL in this case. The initial hemoglobin level is 12g/dL. We can now plug these values into the formula: ABL = (12g/dL - 8g/dL) x 30kg. This simplifies to ABL = 4g/dL x 30kg = 120ml. Therefore, the allowable blood loss is 120ml.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because it does not take into account the initial hemoglobin level or the weight of the patient.
**Option B:** This option is incorrect because it calculates the allowable blood loss as a percentage of the initial hemoglobin level, rather than using the formula ABL = (Initial Hemoglobin - Threshold Hemoglobin) x Weight in kg.
**Option C:** This option is incorrect because it does not provide a numerical value for the allowable blood loss.
**Clinical Pearl / High-Yield Fact**
When calculating allowable blood loss, it's essential to use the correct formula and to consider the patient's weight and the threshold hemoglobin level. This can help prevent unnecessary transfusions and ensure that patients receive the right amount of blood during surgery.
**Correct Answer:** C. 120ml