Before a surgery to take place, what is the allowable or estimated profuse blood loss in a female patient weighing 60 kg, if her initial hematocrit is 45% and final hematocrit is 30%?

1. A

   1200 mL

2. B

   1300 mL

3. C

   1500 mL

4. D

   1600 mL

Appeared in: Combined AIIMS - 2020 (Jodhpur, Bhopal, Patna, Raipur)

Explanation

• derived by first calculating the patient's Estimated Blood Volume (EBV) and then applying the formula for Allowable Blood Loss (ABL).
• The EBV for a 60 kg female is estimated as 60 kg × 65 mL/kg = 3900 mL.
• The ABL formula is: EBV × (Initial Hct - Final Hct) / Initial Hct.
• Substituting the values: 3900 mL × (45% - 30%) / 45% = 3900 mL × (15/45) = 3900 mL × (1/3).
• This calculation results in an allowable blood loss of 1300 mL.

Why Other Options Were Wrong

• Option A: This value is incorrect and likely results from a miscalculation, such as using an incorrect formula or an inaccurate estimate for the patient's blood volume.
• Option C: This value is incorrect. It is close to the result (1560 mL) obtained when using a different, more complex formula (Gross's formula) which uses the average hematocrit in the denominator: ABL = EBV × (Hi - Hf) / [(Hi + Hf)/2]. For this question, the simpler formula is intended.
• Option D: This value is incorrect. It is close to the result (1680 mL) obtained using Gross's formula and a higher estimate for blood volume (70 mL/kg instead of 65 mL/kg).

Related Visual

Clinical Relevance

• Nursing practice connection: Safe nursing care depends on performing Calculation of Allowable Blood Loss (ABL) before surgery in the correct sequence, documenting the action clearly, and monitoring for the expected response.
• Estimating allowable blood loss is a critical part of preoperative planning, especially for surgeries with a high risk of hemorrhage.
• This calculation helps the surgical and anesthesia teams to anticipate the need for blood transfusions and have blood products readily available, which is crucial for patient safety.
• Knowing the ABL allows the team to set a trigger point for transfusion, preventing severe anemia and hypovolemic shock.

How to Approach the Question

• First, identify the question as a calculation problem requiring a specific formula.
• Extract all the necessary numerical data from the question: patient's weight (60 kg), initial hematocrit (45%), and final hematocrit (30%).
• Recall or identify the two main steps: 1. Calculate Estimated Blood Volume (EBV). 2. Calculate Allowable Blood Loss (ABL).
• For Step 1, use the standard estimate for an adult female's blood volume (65 mL/kg) and multiply by the patient's weight.
• For Step 2, apply the standard formula: ABL = EBV × (Initial Hct - Final Hct) / Initial Hct.
• Substitute the given values into the formula and perform the calculation carefully.

Concept Tested & Keywords

• Concept Tested: Calculation of Allowable Blood Loss (ABL) before surgery.
• Stem keywords: surgery, allowable blood loss, estimated profuse blood loss, female patient, 60 kg, initial hematocrit 45%, final hematocrit 30%
• Lead-in keywords: what is
• Clinical cues: Patient weight of 60 kg is used to estimate total blood volume.
• Clinical cues: Initial and final hematocrit values define the acceptable drop in red cell concentration.

Question ID

QrlpgzK3rx5K-FCRusOTKc

Copy ID

Reference Book

E6 Gynecology Williams p. 6-24