TOTALANESTHESIA
Patient Parameters
kg
g/dL
g/dL
Estimated Blood Volume
4,900
mL
EBV factor used70 mL/kg
Formula
Male: 70 mL/kg
Female: 65 mL/kg
Obese: 60 mL/kg
EBV = Weight × Factor
Allowable Blood Loss (ABL)
3,267
mL before transfusion trigger
Hgb drop allowed14 → 7 g/dL
% of EBV67%
Formula
ABL = EBV × (Hgbi - Hgbt) / Hgbavg
where Hgbavg = (Hgbi + Hgbt) / 2
Fluid Replacement Ratios
Crystalloid (3:1)9,801 mL
Colloid (1:1)3,267 mL
pRBC (1:1)3,267 mL
For blood loss up to ABL
Replace 1 mL blood loss with:
• 3 mL crystalloid, OR
• 1 mL colloid/albumin
Transfusion Estimates
1 unit pRBC raises Hgb by~1 g/dL
Units to reach Hgb 103 units
Expected Hgb after 2 units9 g/dL
Rule of thumb
1 unit pRBC ≈ 300 mL
Raises Hgb ~1 g/dL in 70 kg adult
Raises Hct ~3%
  • Establish large-bore IV access (14-16G) early if significant blood loss anticipated
  • Type and screen (or crossmatch) before surgery if ABL <1500 mL expected blood loss
  • Activate massive transfusion protocol (MTP) if blood loss exceeds 1 blood volume or >150 mL/min
  • Send serial Hgb/Hct, lactate, and ABG to guide ongoing resuscitation
  • Transfuse pRBC:FFP:platelets in 1:1:1 ratio during massive hemorrhage (PROPPR trial)
  • Monitor urine output (target ≥0.5 mL/kg/hr) as indicator of end-organ perfusion
  • Consider point-of-care TEG/ROTEM for coagulation-guided transfusion in complex cases
  • Warm all fluids and blood products when transfusing >2 units to prevent hypothermia
  • Replace calcium (CaCl2 1g IV) after every 4 units pRBC to counteract citrate toxicity
Intraoperative Blood Loss TrackerEBL: 0 mL
mL
Blood Loss vs ABL0% of ABL
0%50%100% (Transfuse)
EBV Reference by Patient Type
Patient TypemL/kg70 kg Example
Adult Male704,900 mL
Adult Female654,550 mL
Obese Adult604,200 mL
Infant (1-12 mo)80—
Neonate (term)85-90—
Premature neonate95-100—
Calculations are estimates. Clinical judgment and laboratory values should guide transfusion decisions.