Calculating mechanical power for pressure-controlled ventilation

Meijden, Siri L. van der; Molenaar, Mitchel; Somhorst, Peter; Schoe, Abraham

doi:10.1007/s00134-019-05698-8

Cited by 58 publications

(37 citation statements)

References 5 publications

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“…Until Becher et al [ 19 ] and Van der Meijden et al [ 20 ] reported two equations to measure the MP in pressure-controlled ventilation, it had been erroneously assessed with equations developed and validated only for volume-controlled ventilation. For example, Serpa Neto et al [ 15 ] computed the MP in a big population of mechanically ventilated patients using a single formula independently of the actual type of ventilation.…”

Section: Discussionmentioning

confidence: 99%

“…However, both these equations can be used only during volume-controlled ventilation with constant inspiratory flow in sedated patients with no spontaneous respiratory drive. During pressure-controlled ventilation, in which the airway pressure is held constant, and the flow is decelerated during the mechanical breath, two alternative equations have been suggested [19,20].…”

Section: Introductionmentioning

confidence: 99%

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Bedside calculation of mechanical power during volume- and pressure-controlled mechanical ventilation

et al. 2020

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Background: Mechanical power (MP) is the energy delivered to the respiratory system over time during mechanical ventilation. Our aim was to compare the currently available methods to calculate MP during volumeand pressure-controlled ventilation, comparing different equations with the geometric reference method, to understand whether the easier to use surrogate formulas were suitable for the everyday clinical practice. This would warrant a more widespread use of mechanical power to promote lung protection. Methods: Forty respiratory failure patients, sedated and paralyzed for clinical reasons, were ventilated in volumecontrolled ventilation, at two inspiratory flows (30 and 60 L/min), and pressure-controlled ventilation with a similar tidal volume. Mechanical power was computed both with the geometric method, as the area between the inspiratory limb of the airway pressure and the volume, and with two algebraic methods, a comprehensive and a surrogate formula. Results: The bias between the MP computed by the geometric method and by the comprehensive algebraic method during volume-controlled ventilation was respectively 0.053 (0.77, − 0.81) J/min and − 0.4 (0.70, − 1.50) J/ min at low and high flows (r 2 = 0.96 and 0.97, p < 0.01). The MP measured and computed by the two methods were highly correlated (r 2 = 0.95 and 0.94, p < 0.01) with a bias of − 0.0074 (0.91, − 0.93) and − 1.0 (0.45, − 2.52) J/ min at high-low flows. During pressure-controlled ventilation, the bias between the MP measured and the one calculated with the comprehensive and simplified methods was correlated (r 2 = 0.81, 0.94, p < 0.01) with mean differences of − 0.001 (2.05, − 2.05) and − 0.81 (2.11, − 0.48) J/min. Conclusions: Both for volume-controlled and pressure-controlled ventilation, the surrogate formulas approximate the reference method well enough to warrant their use in the everyday clinical practice. Given that these formulas require nothing more than the variables already displayed by the intensive care ventilator, a more widespread use of mechanical power should be encouraged to promote lung protection against ventilator-induced lung injury.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Bedside calculation of mechanical power during volume- and pressure-controlled mechanical ventilation

et al. 2020

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“…As the equation for calculation of MP is based on the assumption of VCV with a linear increase of airway pressure during inspiration, it is not suitable for calculating MP during PCV [29]. For PCV, two accurate equations have been proposed, but both require using some parameters (resistances, respiratory system compliance) that are not usually continuously quanti ed and displayed in the ventilator [26,30]. Finally, we used the simpli ed formula for PCV proposed by Becher et al [26] since this equation had acceptable accuracy and routine record by our respiratory therapeutist.…”

Section: Discussionmentioning

confidence: 99%

The Association Between Mechanical Power and Mortality in Ventilated Patients with Pneumonia

Chu

Chuang

et al. 2020

Preprint

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Background: Recent studies reported that mechanical power (MP) has been associated with increased mortality in patients with acute respiratory distress syndrome (ARDS). We aimed to investigate the association between 28-day mortality and MP in patients with severe pneumonia. Methods: In total, 313 patients with severe pneumonia were enrolled. Serial MP was recorded daily for either 21 days or until ventilator support was no longer required. The associations between all variables and 28-day mortality were analyzed using binary logistic regression analyses. Results: The ARDS group (106 patients) demonstrated lower age, higher Acute Physiology and Chronic Health Evaluation II score, lower history of diabetes mellitus, high incidences of shock and jaundice, higher MP and driving pressure on Day 1, and higher death within 28 days than the non-ARDS group. Regression analysis revealed that MP was an independent factor associated with 28-day mortality (odds ratio, 1.041; 95% confidence interval, 1.013-1.071). MP persisted high in non-survivors and low in survivors among the ARDS group, the non-ARDS group and all patients.Conclusions: MP was associated with the 28-day mortality in ventilated patients with severe pneumonia both in the ARDS and non-ARDS groups. MP had better predicted value for 28-day mortality than driving pressure.

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“…The equations estimated power within the following mean ± standard deviation of the reference value: our equation, simplified Becher (sB) [2], comprehensive Becher (cB) [2] and van der Meijden (vdM) [3] were 8.4% ± 5.9%, 19.4% ± 12.9%, 10.0% ± 6.8%, and 16.5% ± 14.6% respectively, Fig. 1.…”

mentioning

confidence: 84%

“…Their "comprehensive" equation accounts for a non-zero rise time, increasing accuracy, but like all complex equations may be challenging for bedside application. Recently, van der Meijden [3] presented a simplified equation, but we and others [4] found that it produces lower accuracy than the comprehensive Becher equation, particularly for patients with long inspiratory time or low flow resistance or compliance ( ) (Fig. S3).…”

mentioning

confidence: 88%

Simple, accurate calculation of mechanical power in Pressure Controlled Ventilation (PCV)

Trinkle

Broaddus

Sturgill

et al. 2021

Preprint

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Power is a promising new metric to assess energy transfer from a ventilator to a patient, as it combines the effects of multiple different parameters into a single comprehensive value. For volume-controlled ventilation (VCV), excellent equations exist for calculating power from basic ventilator parameters, but for pressure-controlled ventilation (PCV), an accurate, easy-to-use equation has been elusive. Here, we present a new power equation and evaluate its accuracy compared to the three published PCV power equations. When applied to a sample of 50 patients on PCV with a non-zero rise time, we found that our equation estimated power within an average of 8.4% ± 5.9% (mean ± standard deviation) of the reference value. This new equation is accurate and simple to use, making it an attractive option to estimate power in PCV cases at the bedside.

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Calculating mechanical power for pressure-controlled ventilation

Cited by 58 publications

References 5 publications

Bedside calculation of mechanical power during volume- and pressure-controlled mechanical ventilation

Bedside calculation of mechanical power during volume- and pressure-controlled mechanical ventilation

The Association Between Mechanical Power and Mortality in Ventilated Patients with Pneumonia

Simple, accurate calculation of mechanical power in Pressure Controlled Ventilation (PCV)

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