Inputs
Venous → arterial offsets (editable)
≈ −0.67 kPa
Educational approximations. PaO₂ is not inferred from venous samples.
Normal ~ 7.35–7.45
Normal: 4.7–6.0 kPa (35–45 mmHg)
Normal: 22–26
Optional (oxygenation)
Used for corrected + expected AG & Stewart
Used in Stewart SIDe
Sea level ≈ 760 mmHg (101.3 kPa)
If lab uses mg/dL, convert ≈ mg/dL ÷ 4.6
Unit toggle converts gas pressures only. Concentrations remain in mmol/L (albumin in g/L).
Stewart: SIDa = (Na + K + Ca + Mg) − (Cl + Lactate). SIDe = 2.46×10⁻⁸×PaCO₂(mmHg)/10−pH + Albmmol/L×(0.123·pH−0.631) + Phos×(0.309·pH−0.469). SIG = SIDa − SIDe.
Stewart: SIDa = (Na + K + Ca + Mg) − (Cl + Lactate). SIDe = 2.46×10⁻⁸×PaCO₂(mmHg)/10−pH + Albmmol/L×(0.123·pH−0.631) + Phos×(0.309·pH−0.469). SIG = SIDa − SIDe.
Interpretation
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References will appear here.
Expected Compensation (Boston + Winter’s)
Metabolic & respiratory rules
- No results yet.
Anion Gap, Delta Ratio & Delta Gap
Albumin-corrected AG & expected AG
- No results yet.
Stewart (SID)
SIDa / SIDe / SIG
- No results yet.
Base Excess (BE)
Siggaard–Andersen / Van Slyke
- No results yet.
Oxygenation (Alveolar Gas, A–a, P/F)
PAO₂, gradients & ratios
- No results yet.
Osmolality & Osmolal Gap
Calculated vs measured
- No results yet.
Visuals
Strong ions (SIDa)
SIDe components
Osmolality components
Charts appear when enough data are present.
Clinical caution
This tool supports clinical reasoning and education. It does not replace clinical judgement, local protocols, or specialist advice.