Surgery

Maximum Allowable Blood Loss (MABL & Surgical Hemorrhage)

Calculates patient estimated blood volume (EBV) and maximum permissible blood loss before transfusion trigger.

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Parameters

Maximum Allowable Blood Loss (MABL & Surgical Hemorrhage) Result

Formula

MABL (mL) = EBV × ([Initial Hct - Target Hct] / Initial Hct)
EBV (mL) = Weight (kg) × Average Blood Volume Factor (60 - 95 mL/kg)

Clinical Pearls

Fundamental anesthesiology safety calculation establishing patient-specific limits before allogeneic red blood cell transfusion is indicated.

Limitations

Assumes normovolemic hemodilution with prompt fluid replacement; does not account for acute active surgical hemorrhage where volume resuscitation cannot keep pace with loss.