Summary of Mechanical Power in Pressure-Controlled Ventilation: A Simple and Reliable Bedside Method Snoep JWM, Rietveld PJ, van der Velde-Quist F, de Jonge E, Schoe A. Crit Care Explor. 2025.
Abstract
This study presents a newly proposed equation for calculating mechanical power (MP) in pressure-controlled ventilation (PCV) that is both simple and accurate for bedside use. The authors compared their method—using plateau pressure (Pplat)—against the gold standard geometric method and other existing equations, including those by van der Meijden, Becher, and Trinkle. The new equation showed minimal bias and good agreement with the reference method, making it suitable for routine clinical practice, especially in ICUs lacking advanced analytics or monitoring software.
Key Points:
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Importance of Mechanical Power MP quantifies the energy delivered to the lungs per minute and integrates variables such as tidal volume (VT), driving pressure, flow, respiratory rate, and PEEP—all contributors to ventilator-induced lung injury (VILI).
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Limitations of Existing Methods Many MP calculation methods are either complex (e.g., Becher’s comprehensive formula) or inaccurate at the bedside, especially when accounting for pressure rise time and nonlinear pressure-volume (PV) loop behavior in PCV.
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The New Proposed Equation The new equation is: MP = 0.098 × RR × VT × Pplat, using respiratory rate (RR), tidal volume (VT in liters), and plateau pressure (Pplat in cm H₂O). This formula simplifies bedside calculation while retaining good accuracy.
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Comparison with Other Equations The new method showed the lowest bias (0.2 J/min) and tight limits of agreement (–3.1 to +3.4 J/min) compared to more complex alternatives, which had wider biases and overestimated MP.
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Study Population and Setting The study included 56 measurements from 42 patients (mostly with COVID-19) in a single ICU in the Netherlands, all sedated and without spontaneous breathing activity, ensuring controlled measurement conditions.
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Reference Method: Geometric Analysis The gold standard used numerical integration of the area under the dynamic PV loop (geometric method) to determine true MP, against which all equations were compared.
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Rise Time and PV Loop Shape Consideration Becher’s simplified model overestimates MP by ignoring pressure rise time. The authors’ equation corrects this by using Pplat instead of peak pressure, indirectly adjusting for nonlinearity in the inspiratory limb.
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Applicability and Limits The equation is valid for patients in PCV mode, not for those on volume-controlled ventilation (VCV) or with spontaneous breathing efforts. Errors increased slightly with very high airway resistance.
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Clinical Usability Given its simplicity and minimal equipment requirement (just a ventilator capable of inspiratory hold), this method is feasible in most ICU settings lacking integrated computational tools.
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Future Research Needs The authors call for validation in broader ICU populations beyond COVID-19, exploration of precise MP thresholds linked to VILI or mortality, and testing in ventilators with variable rise times.
Conclusion
This study introduces a practical, accurate, and easy-to-use equation for calculating mechanical power in pressure-controlled ventilation. By incorporating plateau pressure, the method approximates gold-standard measurements and offers a feasible bedside alternative for improving ventilator management and reducing lung injury.
Listen to the following podcast on “New Equation to estimate Mechanical Power during mechanical ventilation. mM Equation” by Society of Mechanical Ventilation
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