Mosteller
Commonly used practical adult default with simple, reproducible calculation.
BSA = √((H × W) / 3600)
Typical use: routine adult perfusion indexing.
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 formulasEnter height and weight to compare formulas.
Blood Flow Rate by Cardiac Index
BSA-based adult CPB flow · weight-indexed reference
mL/kg/min is shown as a weight-indexed reference conversion, not a separate adult CPB target.
Lean Blood Flow (Obesity Adjusted)
Obesity-adjusted reference flow guidance.
Lean BSA: — (Target BMI 25)
Lean Weight: —
Lean Weight: —
⚠️ Obese Patient Heparin Alert
TBW-based heparin dosing may cause overdose. Most guidelines recommend IBW or Adjusted Body Weight.
Methodology & clinical notes
This calculator estimates body surface area and BSA-indexed CPB flow references for perfusion planning. Formula details and evidence notes are summarized in the extended section below.
- 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 sheet: Blood flow rows are BSA-indexed adult CPB references by cardiac index, with mL/kg/min shown only as a secondary weight-indexed conversion.
- Clinical interpretation: Use these values as reference guidance and interpret them with patient status, institutional practice, and perfusion adequacy markers.
Extended clinical notes & evidence
Additional interpretation for BSA formula behavior, CPB flow indexing context, and obesity-specific considerations.
BSA formula notes
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 adult CPB pump flow references across different body sizes. The primary flow framework is BSA × CI; mL/kg/min is shown only as a weight-indexed reference conversion for users who want to view the same BSA-based flow by body weight.
Cardiac Index (CI) = Pump Flow (L/min) ÷ BSA (m²)
Pump Flow (L/min) = BSA (m²) × CI (L/min/m²)
mL/kg/min = [Pump Flow (L/min) × 1000] ÷ weight (kg)
- BSA-based indexing can help standardize flow interpretation across different patient sizes.
- mL/kg/min should not be used alone to set an adult CPB target, especially when total body weight may overstate metabolic demand.
- Lower temperatures reduce metabolic demand, so acceptable indexed flow may vary with temperature.
- Indexed flow is a starting point, not a complete adequacy measure.
- Temperature, hemoglobin/hematocrit, SvO₂, lactate, arterial pressure, oxygen delivery adequacy, 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.
- 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.
- 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.
- Boyd E. The Growth of the Surface Area of the Human Body.