Rethinking respiratory assessment: the emerging role of non-invasive P_mus estimation in real-time monitoring

Dear Editor,

Monitoring patient effort or muscle pressure (P_mus) during mechanical ventilation is essential to prevent diaphragm injury.(¹-³) Excessive inspiratory effort may cause patient self-inflicted lung injury and diaphragm overuse, whereas insufficient effort may result in rapid diaphragm atrophy.(⁴)

Both under- and over-assistance can disrupt the balance required to preserve respiratory muscle function.(¹-³,⁵) Quantifying P_mus enables clinicians to tailor ventilator support, ensuring protective lung strategies while maintaining appropriate diaphragmatic activity.(¹)

Traditionally, patient effort has been assessed using invasive techniques, such as esophageal pressure monitoring, which require specialized equipment and clinician expertise.(⁵) However, recent advances have enabled the development and integration of noninvasive methods for P_mus assessment in modern ventilators. These systems calculate P_mus based on the equation of motion using real-time measurements of respiratory system compliance and resistance. This approach enables accurate breath-by-breath, real-time monitoring of patient effort, offering a reliable and user-friendly alternative to invasive methods while supporting continuous bedside assessment (Figure 1).

Figure 1
Chart representing the muscle pressure and the airway, elastic, and resistive pressures

REFERENCES

• ¹ Goligher EC, Dres M, Patel BK, Sahetya SK, Beitler JR, Telias I, et al. Lung- and diaphragm-protective ventilation. Am J Respir Crit Care Med. 2020;202(7):950-61.
• ² Khemani RG, Hotz JC, Klein MJ, Kwok J, Park C, Lane C, et al. A Phase II randomized controlled trial for lung and diaphragm protective ventilation (Real-time Effort Driven VENTilator management). Contemp Clin Trials. 2020;88:105893.
• ³ Castellví-Font A, Goligher EC, Dianti J. Lung and diaphragm protection during mechanical ventilation in patients with acute respiratory distress syndrome. Clin Chest Med. 2024;45(4):863-75. Review.
• ⁴ Goligher EC, Dres M, Fan E, Rubenfeld GD, Scales DC, Herridge MS, et al. Mechanical Ventilation-induced Diaphragm Atrophy Strongly Impacts Clinical Outcomes. Am J Respir Crit Care Med. 2018;197(2):204-13.
• ⁵ Yoshida T, Torsani V, Gomes S, De Santis RR, Beraldo MA, Costa EL, et al. Spontaneous effort causes occult pendelluft during mechanical ventilation. Am J Respir Crit Care Med. 2013;188(12):1420-7.

• Associate Editor:
  Kenneth Gollob Hospital Israelita Albert Einstein, São Paulo, SP, Brazil ORCID: https://orcid.org/0000-0003-4184-3867

Publication Dates

• Publication in this collection
  24 Oct 2025
• Date of issue
  2025

History

• Received
  20 June 2025
• Accepted
  09 July 2025