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Introduction

Blood transfusion in pediatric neurosurgery, particularly for procedures like craniosynostosis repair, requires a careful and calculated approach. The unique physiological characteristics of children—especially infants—demand precise blood volume estimation, loss assessment, and transfusion decision-making to ensure safety and optimal outcomes.

Below are key calculations and considerations when planning for blood transfusion in pediatric neurosurgical settings:

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1. Estimated Blood Volume (EBV)

Understanding the Estimated Blood Volume (EBV) is essential for predicting transfusion needs.

Age Group	Estimated Blood Volume (ml/kg)
Preterm neonates	90–100
Full-term neonates	85–90
Infants (<12 months)	80
Children (>12 months)	75

For example, in craniosynostosis surgeries, which often involve infants, use 80 ml/kg; for children like a 5-year-old patient, use 75 ml/kg.

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2. Maximum Allowable Blood Loss (MABL)

To guide intraoperative transfusion decisions, MABL is calculated as:

MABL = EBV × (Starting Hct – Target Hct) / Starting Hct

This helps determine the volume of blood a child can safely lose before transfusion becomes necessary.

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3. Packed Red Blood Cell (PRBC) Transfusion Volume

To avoid over-transfusion:

PRBC Volume (mL) = Weight (kg) × Desired Hb rise (gm/dL) × Transfusion Factor

Where:

• Transfusion Factor = 3 / PRBC Hct
  (Typical PRBC Hct = 0.60–0.65)

Example: 10 mL/kg of PRBC with Hct 60% gives ~2 gm/dL rise in Hb.

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4. Methods of Estimating Blood Loss

Estimating intraoperative blood loss in neurosurgery can be difficult due to hidden bleeding. Use a combination of the following:

• Visual assessment of the field
• Calibrated suction canister readings
• Weighing surgical sponges
• Serial haematocrit levels from ABG
• Thromboelastography (TEG) or ROTEM for coagulation monitoring

Note: Blood may be concealed under drapes or on instruments—constant vigilance is critical.

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5. Factors Influencing Transfusion Decisions

There is no universal transfusion trigger; decisions must be individualized based on:

• Preoperative haematocrit and baseline haemoglobin
• Child’s weight and age
• Surgical pathology (e.g., craniosynostosis often involves blood loss >20–500% of EBV)
• Comorbidities affecting oxygen delivery (e.g., cyanotic heart disease)

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Transfusion Thresholds and Recommendations

Scenario	Transfusion Recommendation
Hb ≥ 7 gm/dL and stable	No transfusion needed
Hb < 5 gm/dL or critically ill	Transfusion indicated
Hb 5–7 gm/dL	Individualized decision
Target Hb after transfusion	7.0 – 9.5 gm/dL
Minimum Hct for craniotomy	25%
Optimum cerebral oxygen delivery	Hct ~30%
Acute brain injury (e.g., trauma)	Transfuse if Hb 7–10 gm/dL
Massive transfusion (>50% EBV in 3 hrs or 100% in 24 hrs)	Use PRBC : FFP : Platelet = 2 : 1 : 1

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Summary

In pediatric neurosurgery, particularly in high-risk procedures like craniosynostosis repair, blood transfusion must be:

✅ Carefully calculated using weight-based formulas
✅ Guided by clinical condition, not just haemoglobin numbers
✅ Continuously reassessed using haematocrit, ABG, and coagulation studies
✅ Supported by a multidisciplinary team for timely intervention

By integrating these evidence-based parameters into your intraoperative workflow, you can significantly improve transfusion safety and patient outcomes.

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Stay updated. Stay meticulous. Pediatric neurosurgery demands nothing less.