Anesthesia Infusion Calculator

Patient Weights

Body composition calculations

Sex

Height

Weight

TBW

—

IBW

—

LBW

—

AdjBW

—

BMI

—

BSA

—

Formula Reference

IBW (Devine): ♂ 50 + 2.3×(in over 60) kg · ♀ 45.5 + 2.3×(in over 60) kg
LBW (Janmahasatian): ♂ 9270·TBW / (6680 + 216·BMI) · ♀ 9270·TBW / (8780 + 244·BMI)
AdjBW: IBW + 0.4·(TBW − IBW) — use when TBW > 120% IBW
BSA (Mosteller): √(ht_cm × wt_kg / 3600)

Which Weight to Use?

General anesthesia guidance

Propofol — induction: TBW (transient effect), but titrate to effect; consider LBW in morbid obesity.

Propofol — maintenance: LBW or AdjBW preferred in obese patients.

Remifentanil, Sufentanil, Fentanyl: LBW or IBW — opioids redistribute poorly to fat.

Rocuronium, Vecuronium: IBW (prolonged duration if TBW used).

Succinylcholine: TBW — increased pseudocholinesterase activity.

Dexmedetomidine: TBW (most references).

Ketamine: IBW or LBW for maintenance infusion.

Vasoactives (phenyl, norepi, epi): Typically TBW, but most are titrated to effect regardless.

Heparin, LMWH: TBW in most protocols (with dose caps).

TBW— IBW— LBW— AdjBW—

⚠ Clinical Use Disclaimer
This tool is a computational aid only. Verify all calculations, dilutions, and dosing ranges against your institutional protocols, current drug references, and patient-specific factors before administration. The user bears sole responsibility for clinical decisions.

Standard Dilutions

Common anesthesia & ICU concentrations

Drug	Mix	Final Conc

Pressor Dilution Recipes

Step-by-step bag preparation

⚠ Institutional Variation
Concentrations vary by institution. Confirm your facility's standard mix before preparing. Double-check math and have a second licensed provider verify high-alert medication dilutions per policy.