Heparin Management for CPB Perfusion

Estimate UFH bolus guidance with TBW/IBW/ABW strategy, ACT checkpoints, and obesity safety cues for perfusion workflows.

Heparin dosing in CPB is weight-indexed but should be interpreted with ACT trend, hemodilution, temperature, and local protocol.

This page focuses on adult perfusion use: initial UFH bolus planning, additional bolus guidance, and resistance/reversal context as quick bedside support.

Heparin Management (CPB)

Calculate an initial loading dose with weight strategy safeguards and optional flow targets; toggle resistance cues when ACT response is low.

Patient parameters

Adult CPB

Height (cm)

Weight (kg)

Sex

ACT monitoring per protocol

Weight strategy

Auto switches to ABW when BMI ≥ 30 to reduce overdose risk.

Auto logic: BMI < 30 → TBW; BMI 30–39 → ABW (0.4 correction); BMI ≥ 40 → ABW (0.3) with obesity safety cues.

Initial dose (u/kg)

Enter patient parameters to calculate

Height, weight, and dose are required.

BMI

IBW (Devine)

- kg

Devine formula

BSA (Mosteller)

- m²

Dosing weight

- kg

Initial bolus

Additional bolus-

Sensitivity (weight strategy vs dose @300 u/kg)

StrategyWeightDose / Δ

TBW--

ABW (0.4)--

IBW--

In severe obesity, TBW-based dosing can exceed 40,000 U; reassess dosing when values climb this high.

Quick protocol

Bolus -
Wait 3–5 min → Check ACT
Monitor ACT q30min during CPB
If ACT low: + bolus

Clinical pearls

ACT is influenced by hemodilution, hypothermia, platelet count, factor levels, antithrombin activity, and device-specific variability.
TBW-based heparin dosing is commonly used for CPB initiation, but it may produce very large doses in severe obesity.
IBW-based dosing may reduce overdose risk in obesity, but IBW alone can underdose if ACT, heparin concentration, or anti-Xa is not confirmed.
ABW is a compromise between TBW and IBW and may be useful when TBW appears excessive but IBW seems too conservative.
Failure to reach target ACT after an adequate bolus should prompt reassessment for heparin resistance, low antithrombin, sampling error, circuit factors, or drug/device effects.

TBW — Total Body Weight

TBW is actual measured body weight and is commonly used for initial CPB heparin dosing. In severe obesity, TBW can generate very large bolus estimates that may increase bleeding concern without reliably improving anticoagulation.

IBW — Ideal Body Weight

IBW is height/sex-based and may be useful when adiposity is high and heparin distribution is non-linear. IBW can reduce overdose risk, but under-anticoagulation remains possible unless ACT, heparin concentration, or anti-Xa confirms response.

ABW — Adjusted Body Weight

ABW provides an intermediate dosing weight between IBW and TBW when TBW appears excessive and IBW too conservative.

ABW = IBW + 0.4 × (TBW − IBW)

Use as a comparison reference, not a universal replacement for local protocol.

How to apply TBW, IBW, and ABW in practice

Non-obese adult CPB patients: TBW-based dosing is usually the simplest starting point.
Mild to moderate obesity: TBW may still be used, but compare IBW or ABW if calculated dose appears unusually high.
Severe obesity (especially BMI ≥ 35 kg/m²): display TBW, IBW, and ABW side by side; TBW may overestimate and IBW may underestimate need.
Known heparin resistance or low antithrombin: do not rely on weight dosing alone; confirm with ACT response and consider anti-Xa/heparin concentration per protocol.
High bleeding-risk cases: lower calculated dose is not automatically safer if anticoagulation is inadequate.

Obesity-specific interpretation

In obesity, blood volume and lean mass do not rise in direct proportion to total body weight, and adipose tissue has limited heparin distribution. Treat this heparin dose calculator as a comparison aid for CPB heparin dosing and cardiopulmonary bypass anticoagulation planning.

TBW dose: conventional actual-weight estimate.
IBW dose: conservative height-based estimate.
ABW dose: intermediate estimate that partially accounts for excess body weight.
ACT response: determines whether the selected dose achieved the anticoagulation target.
Anti-Xa or heparin concentration: useful when ACT is unreliable or discordant.

Safest interpretation: calculated dose + measured anticoagulation response + patient context.

Heparin resistance and ACT interpretation

Suspect heparin resistance when expected UFH bolus does not achieve institutional ACT target. Contributors include low antithrombin, elevated heparin-binding proteins, inflammation, thrombocytosis, prior heparin exposure, and high factor VIII/fibrinogen.

ACT is rapid point-of-care guidance but not a pure heparin concentration test; values are affected by hypothermia, hemodilution, platelet count, factor levels, device type, aprotinin exposure, and sampling conditions.

Confirm sample quality and device validity.
Confirm full bolus delivery.
Consider additional heparin per institutional protocol.
Consider anti-Xa or heparin concentration testing when available.
Consider targeted antithrombin supplementation when AT-mediated resistance is likely.

Guideline anchors (summary)

STS/SCA/AmSECT 2018: Initial heparin dosing and monitoring should confirm adequate anticoagulation before CPB, commonly with ACT-based institutional targets.
ACT target: many protocols use thresholds around ≥ 400–480 seconds, but exact targets depend on local protocol, device type, and surgical context.
Heparin concentration / anti-Xa: consider additional monitoring when ACT is unreliable or discordant (hypothermia, hemodilution, inflammation, obesity).
Antithrombin: UFH effect depends on antithrombin activity; low AT can contribute to heparin resistance and may require targeted management.
Obesity: TBW, IBW, and ABW are dosing references, not automatic orders; final dosing should be confirmed by measured anticoagulation response.

Selected references

Shore-Lesserson L, Baker RA, Ferraris VA, et al. STS/SCA/AmSECT Clinical Practice Guidelines: Anticoagulation during Cardiopulmonary Bypass. Ann Thorac Surg. 2018.
PubMed Free full text
Wahba A, et al. 2024 EACTS/EACTAIC/EBCP Guidelines on cardiopulmonary bypass in adult cardiac surgery. Eur J Cardiothorac Surg / Interdiscip Cardiovasc Thorac Surg. 2025.
PubMed Journal Guideline
Vienne M, et al. Adjusted calculation model of heparin management during cardiopulmonary bypass in obese patients. Eur J Anaesthesiol. 2018.
PubMed
Bull BS, Korpman RA, Huse WM, Briggs BD. Heparin therapy during extracorporeal circulation. I. Problems inherent in existing heparin protocols. J Thorac Cardiovasc Surg. 1975.
PubMed
Bull BS, Huse WM, Brauer FS, Korpman RA. Heparin therapy during extracorporeal circulation: II. The use of a dose-response curve to individualize heparin and protamine dosage. J Thorac Cardiovasc Surg. 1975.
PubMed DOI

Heparin Management for CPB Perfusion

Heparin Management (CPB)

Patient parameters

Pediatric safety notice

Extreme obesity safety notice

Morbid obesity management

TBW — Total Body Weight

IBW — Ideal Body Weight

ABW — Adjusted Body Weight