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The calculation of mechanical power is not suitable for intra-patient monitoring under pressure-controlled ventilation

  • Zhanqi Zhao
  • Inez Frerichs
  • Huaiwu He
  • Yun LongEmail author
  • Knut Möller
  • Ary Serpa Neto
  • Marcus J. Schultz
Correspondence

Original correspondence from Dr. Zhao et al.

Dear Editor,

We read with interest the paper by Serpa Neto et al. showing that mechanical power (MP) of ventilation is independently associated with in-hospital mortality and other outcomes in critically ill invasively ventilated patients [1]. Although MP might become a practical clinical outcome predictor, we would like to point out that MP calculation may not be suitable for intra-individual monitoring of ventilator-related causes of lung injury under pressure-controlled ventilation.

Serpa Neto et al. used a simplified equation for MP calculation [ 2], which is suitable in patients under volume-controlled ventilation. In pressure-controlled mode, R aw cannot be substituted by ( P peak –  P plat )/Flow and Flow by V T/ T insp. Further, an increase in V T is always negatively weighted in both original and simplified calculations, while the effect of recruitment is neglected. Considering the original calculation in [ 2]:
$$ {\text{MP}} = 0.098 \times...

Notes

Compliance with ethical standards

Conflicts of interest

The authors declared that they have no conflict of interest.

References

  1. 1.
    Serpa Neto A, Deliberato RO, Johnson AEW, Bos LD, Amorim P, Pereira SM, Cazati DC, Cordioli RL, Correa TD, Pollard TJ, Schettino GPP, Timenetsky KT, Celi LA, Pelosi P, Abreu GDM, Schultz MJ, PROVE Network Investigators (2018) Mechanical power of ventilation is associated with mortality in critically ill patients: an analysis of patients in two observational cohorts. Intensive Care Med 44:1914 CrossRefGoogle Scholar
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    Gattinoni L, Tonetti T, Cressoni M, Cadringher P, Herrmann P, Moerer O, Protti A, Gotti M, Chiurazzi C, Carlesso E, Chiumello D, Quintel M (2016) Ventilator-related causes of lung injury: the mechanical power. Intensive Care Med 42:1567–1575CrossRefGoogle Scholar
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    Network Acute Respiratory Distress Syndrome, Brower RG, Matthay MA, Morris A, Schoenfeld D, Thompson BT, Wheeler A (2000) Ventilation with lower tidal volumes as compared with traditional tidal volumes for acute lung injury and the acute respiratory distress syndrome. N Engl J Med 342:1301–1308CrossRefGoogle Scholar
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    Huhle R, Serpa Neto A, Schultz MJ, Gama de Abreu M (2018) Is mechanical power the final word on ventilator-induced lung injury?—no. Ann Transl Med 6:394–397CrossRefGoogle Scholar
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    Hamlington KL, Bates JHT, Roy GS, Julianelle AJ, Charlebois C, Suki B, Smith BJ (2018) Alveolar leak develops by a rich-get-richer process in ventilator-induced lung injury. PLoS One 13:e0193934CrossRefGoogle Scholar

Copyright information

© Springer-Verlag GmbH Germany, part of Springer Nature 2019

Authors and Affiliations

  • Zhanqi Zhao
    • 1
    • 2
  • Inez Frerichs
    • 3
  • Huaiwu He
    • 4
  • Yun Long
    • 4
    Email author
  • Knut Möller
    • 2
  • Ary Serpa Neto
    • 5
    • 6
    • 7
  • Marcus J. Schultz
    • 5
    • 8
  1. 1.Department of Biomedical EngineeringFourth Military Medical UniversityXi’anChina
  2. 2.Institute of Technical MedicineFurtwangen UniversityVillingen-SchwenningenGermany
  3. 3.Department of Anesthesiology and Intensive Care MedicineUniversity Medical Center of Schleswig–Holstein Campus KielKielGermany
  4. 4.Department of Critical CareChinese Academy of Medical Sciences, Peking Union Medical College HospitalBeijingChina
  5. 5.Department of Intensive Care and Laboratory of Experimental Intensive Care and Anesthesiology (LEICA)Academic Medical CenterAmsterdamThe Netherlands
  6. 6.Department of Critical Care MedicineHospital Israelita Albert EinsteinSão PauloBrazil
  7. 7.Laboratory for Critical Care ResearchHospital Israelita Albert EinsteinSão PauloBrazil
  8. 8.Faculty of Tropical Medicine, Mahidol Oxford Tropical Medicine Research Unit (MORU)Mahidol UniversityBangkokThailand

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