Ventilation Constraint Model

Patient for ARDSnet Vt targeting

Sex

Height (cm)

Weight (kg)

Ventilator settings click a column header to focus

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Gas exchange

Calculated trend shown as 3-point sparkline (baseline → 4h → current)

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Overall status

Loop view · 24 h temporal window

Now

Dead space

P(a−ET)CO₂ & Vd/Vt — fast-reference differential cue

Vd/Vt —

Mechanical load detail

Normal Caution Severe Baseline 4h ago Current

Ventilatory constraint suggestions

Rule-based flags for the Current timepoint · click a column header to focus a different timepoint

Clinical interpretation

Normal: MP <12 J/min, PF ratio >200 (SF ratio equivalent), pH >7.3. Consistent with lung-protective ventilation and adequate gas exchange — continue current strategy with routine review.

Caution: MP 12–17 J/min, PF 100–200, or pH 7.2–7.29. Rising risk of ventilator-induced lung injury or respiratory decompensation — review driving pressure, PEEP titration, sedation/synchrony, and consider early prone positioning or recruitment where indicated.

Severe: MP >17 J/min, PF <100, or pH <7.2. Severe physiological derangement — escalate urgently (neuromuscular blockade, prone, rescue strategies including ECMO referral) and revise the ventilator strategy without delay.

Formulas — MP (VCV, Gattinoni) = 0.098 × RR × Vt(L) × (Ppeak − ½(Pplat−PEEP)) · MP (PCV, Becher) = 0.098 × RR × Vt(L) × (ΔP_insp + PEEP), where ΔP_insp = Pplat − PEEP · Compliance = Vt ÷ (Pplat − PEEP) · Peak flow = Vt(L) ÷ Ti · Resistance = (Ppeak − Pplat) ÷ Peak flow (VCV; not directly derivable from static inputs alone in PCV) · PF ratio = PaO₂(mmHg) ÷ (FiO₂/100), with PaO₂ converted from kPa (×7.5) · SF ratio = SpO₂ ÷ FiO₂ × 100 · P(a−ET)CO₂ = PaCO₂ − EtCO₂ (kPa) · Vd/Vt (Enghoff) = (PaCO₂ − EtCO₂) ÷ PaCO₂. Intended for educational use — not a substitute for clinical judgement.