Neonatal Ca-Phos Solubility Calculator: For Professionals only

Neonatal Ca-Phos Solubility Calculator | ASPEN/ESPGHAN

      Clinical Disclaimer: This calculator uses empirically-derived solubility equations based on published precipitation curves (Dunham 1991, Mo-Suwan, Anderson 2022). Always verify with your institutional pharmacy and use inline filtration. Precipitation can occur at any time.
    

💧

TPN Composition

Amino Acid Product

Amino Acid Concentration (g/dL or %)

Typical: 1.0-3.0% | Final concentration in TPN bag

Amino Acid Dose (g/kg/day)

TPN Volume (mL/kg/day)

Dextrose Concentration (%)

Higher dextrose slightly improves solubility

Cysteine HCl (mg/g AA)

40 mg/g = standard | 0 = none | Each 160mg = 1 mmol HCl

⚡

Calcium & Phosphate

Calcium Salt Form

Calcium (mEq/kg/day)

Calcium (mg/kg/day)

1 mEq Ca Gluconate ≈ 45 mg elemental Ca | 1 mEq CaCl2 ≈ 20 mg

Phosphate (mmol/kg/day)

Phosphate (mg/kg/day)

1 mmol P ≈ 31 mg P | NaPhos: 4 mEq Na : 3 mmol P/mL | KPhos: 4.4 mEq K : 3 mmol P/mL

Magnesium (mEq/kg/day)

Effect on Ca-Phos solubility is negligible but included

🥛

Lipid Information

TPN Type

Lipid Emulsion (g/kg/day)

Lipid Concentration (%)

Lipid Infusion Time (hours/day)

Patient Weight (kg)

📈

Solubility Results

Click “Calculate Solubility” to see results

📊

Visual Solubility Curve

Safe Zone (Below Curve)

Precipitation Zone (Above Curve)

Your Order

📝

Step-by-Step Calculation

Click “Calculate Solubility” to see calculations

📖

Published Solubility Limits (mmol/L at Ca:P 1:1)

AA Product	1% AA	2% AA	3% AA
TrophAmine (no cysteine)	~5.5	~8.0	~10.5
TrophAmine + Cysteine 40mg/g	~7.0	~10.0	~13.0
Premasol (no cysteine)	~5.5	~8.0	~10.5
Vaminolact	~5.5	~8.0	~10.5
Aminosyn II / Travasol	~4.0	~6.0	~8.0

Values represent maximum combined Ca+Phos (mmol/L) at 1:1 molar ratio. Higher AA and cysteine improve solubility. Calcium gluconate permits higher solubility than calcium chloride.

⚠

Safety Guidelines

General Rules:
• Ca:P Molar Ratio: Target 1.3:1 (ASPEN) | SGA/IUGR: 0.8-1.1:1
• Ca:P Mass Ratio: Target 1.3-1.7:1 | SGA/IUGR: 0.8-1.1:1
• 3-in-1 TNA Upper Limits: 8.5 mEq Ca + 20 mmol P per liter
• Peripheral Line: Give Ca separately; only add Phos to TPN
• Central Line: Both Ca and Phos can be in TPN

Factors INCREASING Solubility:
• Higher amino acid concentration
• Addition of cysteine HCl (lowers pH)
• Higher dextrose concentration
• Calcium gluconate (vs calcium chloride)
• Lower storage temperature

Factors DECREASING Solubility:
• Higher pH (less cysteine, different AA product)
• Calcium chloride (vs gluconate)
• Higher temperature
• 3-in-1 admixture (lipids raise pH)
• Longer hang time

🔧

Equations Used (Anderson 2022)

Equation 1: 2-in-1 PN (separate lipids) Precipitation Limit = AAF + (CYS x AAF)/100 Equation 2: 2-in-1 with Y-site lipids Precipitation Limit = AAF + (CYS x AAF)/100 – (FIR x FIT x FPP x AAF)/(AA x WT x 1000) Equation 3: 3-in-1 TNA Precipitation Limit = AAF + (CYS x AAF)/100 – (FAT x AAF)/(AA x 10) Equation 4: Solution Factor Solution Factor = [(Ca mEq/L)^0.863 x (P mmol/L)^1.19] / (Final AA %) Compatibility Check: If Solution Factor < Precipitation Limit = SAFE If Solution Factor >= Precipitation Limit = PRECIPITATION RISK