Mechanical Power (Ventilation) Calculator
Gattinoni long-form equation for passive volume-controlled ventilation with square flow
Version 1.0.0
Model assumptions: passive patient, volume-controlled ventilation (VCV), square/constant inspiratory flow and total positive end-expiratory pressure (PEEP, set plus intrinsic). This equation is not interchangeable with pressure-controlled ventilation equations.
Mechanical power—J/min
Legacy work per breath—J/breath
Elastic power—J/min
Resistive power—J/min
PEEP power—J/min
Respiratory-system elastance—cmH₂O/L
Airway resistance—cmH₂O·s/L
Inspiratory flow—L/s
Inspiratory time (TI)—s
No universal mechanical-power treatment threshold is applied. Interpret the estimate with the ventilation mode, patient size and clinical context.
No clinical values are intentionally saved by this control.
Equations
Mechanical power — imported Gattinoni long-form VCV implementation
MP = 0.098 × RR × { Vₜ² × [ ½ × (Pplat − PEEPtotal) / Vₜ + (1 / Tᵢ) × (Ppeak − Pplat) / Flow ] + Vₜ × PEEPtotal }MP is J/min; RR is breaths/min; Vₜ is litres; pressures are cmH₂O; Flow is L/s; Tᵢ is seconds. This exactly retains the legacy long-form calculation. It assumes passive volume-controlled ventilation and square flow. The 0.098 factor converts cmH₂O·L to joules.
Inspiratory time and I:E control
I/E = 10^(−s); Tᵢ = (60 / RR) × [(I/E) / (I/E + 1)]The logarithmic slider s runs from −1 to +1. If entered Flow is 0, Flow is derived as Vₜ/Tᵢ; otherwise entered device flow is converted from L/min to L/s.
Power components
Elastic power = 0.098 × RR × ½ × (Pplat − PEEPtotal) × Vₜ; Resistive power = 0.098 × RR × Vₜ² × (1/Tᵢ) × (Ppeak − Pplat)/Flow; PEEP power = 0.098 × RR × PEEPtotal × VₜThe three components sum exactly to the displayed mechanical power.
Legacy work-per-breath output
Legacy work/breath = 0.098 × Vₜ × [½ × (Pplat − PEEPtotal) + (Ppeak − Pplat) + PEEPtotal]This preserves the separately calculated legacy output. It equals MP/RR only when Flow = Vₜ/Tᵢ. The interface warns when entered device flow differs from derived square flow by more than 10%.
Derived respiratory mechanics
Ers = (Pplat − PEEPtotal)/Vₜ; Raw = (Ppeak − Pplat)/FlowErs is cmH₂O/L and Raw is cmH₂O·s/L.
References
- Gattinoni L, Tonetti T, Cressoni M, et al. Ventilator-related causes of lung injury: the mechanical power. Intensive Care Med. 2016;42(10):1567-1575. PMID: 27620287 DOI: 10.1007/s00134-016-4505-2
- Cressoni M, Gotti M, Chiurazzi C, et al. Mechanical power and development of ventilator-induced lung injury. Anesthesiology. 2016;124(5):1100-1108. PMID: 26872367 DOI: 10.1097/ALN.0000000000001056
- Gattinoni L, Marini JJ, Collino F, et al. The future of mechanical ventilation: lessons from the present and the past. Crit Care. 2017;21(1):183. PMID: 28701178 DOI: 10.1186/s13054-017-1750-x