Perfusion Tools

BSA Calculator for Perfusion Flow Guidance in CPB

Calculate BSA first, then estimate indexed pump flow targets (CI 1.0-3.0) for clinical perfusion planning.

Body Surface Area

BSA Calculator

Enter height and weight to calculate BSA and perfusion flow guidance.

BSA (m²)
0.00
BSA Output
—
Formula
Mosteller
TBW BSA may overestimate metabolic demand
BMI: —
Obesity Adjustment: —

Quick summary

Body surface area (BSA) is used to normalize CPB flow and perfusion references to patient size. This calculator estimates BSA and provides indexed flow guidance for clinical context.

Key info

Primary use
Indexed CPB flow guidance
Formula set
Mosteller default; Du Bois, Haycock, Boyd available
Caution
TBW-based BSA may overestimate indexed targets in obesity

Practical note

Use BSA-indexed flow as a starting point and interpret it with temperature, SvO₂, lactate, and local protocol.

Formula Comparison

Other formulas
Enter height and weight to compare formulas.

Blood Flow Rate by Cardiac Index

TBW-based flow guidance.

CI 1.0–3.0
▶ Methodology & clinical notes

This calculator estimates body surface area and BSA-indexed CPB flow targets for perfusion planning.

  • Default formula: Mosteller is used as the primary adult default because it is simple and reproducible.
  • Comparison formulas: Du Bois, Haycock, and Boyd are available to compare formula behavior in selected patients.
  • Flow estimate: Pump flow is estimated from BSA × cardiac index target.
  • Obesity adjustment: TBW-based BSA may overestimate indexed targets in obesity; adjusted or IBW-based references are provided for comparison.
  • Clinical interpretation: Indexed flow is a starting point and should be interpreted with temperature, SvO₂, lactate, hemoglobin, urine output, and local protocol.

Extended clinical notes & evidence

Additional interpretation for BSA formula behavior, CPB flow indexing context, and obesity-specific considerations.

BSA formula notes

Mosteller

Commonly used practical adult default with simple, reproducible calculation.

BSA = √((H × W) / 3600)

Typical use: routine adult perfusion indexing.

Du Bois & Du Bois

Historically important and widely cited as an adult comparison formula.

BSA = 0.007184 × H0.725 × W0.425

Why it matters: helpful reference when comparing formula behavior.

Haycock

Often considered in pediatric body-size estimation and smaller body sizes.

BSA = 0.024265 × H0.3964 × W0.5378

Typical use: pediatric-leaning comparisons in selected patients.

Boyd

Broader body-size modeling, though less common in routine practice.

BSA = 0.0003207 × H0.3 × W(0.7285 − 0.0188 × logW)

Why it matters: offers an additional reference in non-standard body habitus.

Clinical context in CPB

BSA indexing helps normalize pump flow targets across different body sizes and can support more consistent interpretation of perfusion adequacy than body weight alone.

Cardiac Index (CI) = Pump Flow (L/min) ÷ BSA (m²)

  • BSA-based indexing can help standardize flow interpretation across different patient sizes.
  • Lower temperatures reduce metabolic demand, so acceptable indexed flow may vary with temperature.
  • Indexed flow is a starting point, not a complete adequacy measure.
  • SvO₂, lactate, urine output, temperature, and overall clinical context should also be assessed.

Moderate hypothermia may allow lower indexed flow than near-normothermic bypass.

Higher indexed flow targets are commonly used closer to normothermia.

Exact targets should follow local protocol and patient context.

Obesity considerations: TBW-based BSA vs adjusted references

In obesity, TBW-based BSA may overestimate indexed flow targets. In selected patients, adjusted body-size references may better fit clinical interpretation.

Item TBW-based Adjusted / IBW
BSA estimate May overestimate demand May better reflect demand
Indexed flow target May trend higher May be more realistic
Anticoagulation Some centers adjust strategy Follow local protocol
Perfusion assessment Needs SvO₂, lactate, temp context Still needs clinical correlation

ABW = IBW + 0.4 × (TBW − IBW)

  • TBW-based BSA can still be used as a starting point.
  • SvO₂, lactate, temperature, and overall clinical context should guide real-time interpretation.
  • Follow local protocol for heparin and perfusion management.

Selected references

Formula references

  • Mosteller RD. Simplified calculation of body-surface area. N Engl J Med. 1987;317:1098.
    PubMed DOI
  • Du Bois D, Du Bois EF. A formula to estimate the approximate surface area if height and weight be known. Arch Intern Med. 1916;17:863.
    Journal PubMed reprint
  • Haycock GB, Schwartz GJ, Wisotsky DH. Geometric method for measuring body surface area: a height-weight formula validated in infants, children, and adults. J Pediatr. 1978;93:62.
    PubMed Journal
  • Boyd E. The Growth of the Surface Area of the Human Body.
    Book HERO Archive

Contextual CPB interpretation

  • de Somer F et al. Interact Cardiovasc Thorac Surg. 2011.
  • Grocott HP et al. J Thorac Cardiovasc Surg. 2005.
  • Slogoff S et al. Ann Thorac Surg. 1990.

Related tools

GDP Calculator Predicted Hematocrit