Bedside dynamic calculation of mechanical power: A validation study

Area of Science:

• Critical Care Medicine
• Respiratory Physiology
• Mechanical Ventilation

Background:

• Mechanical power is a key factor in ventilator-induced lung injury.
• Accurate bedside calculation of mechanical power is crucial for optimizing ventilation strategies.
• Existing methods for calculating mechanical power may not be readily applicable at the bedside.

Purpose of the Study:

• To develop and validate a novel equation for calculating dynamic mechanical power (MPdyn) at the bedside.
• To utilize the Work of Breathing ventilator (WOBv) parameter in the development of the MPdyn equation.
• To compare the newly developed MPdyn equation with a standard equation (MPstd) including PEEP.

Main Methods:

• Developed the MPdyn equation based on WOBv and minute volume, incorporating PEEP for comparison with MPstd.
• Recruited forty adult patients with Acute Respiratory Distress Syndrome undergoing invasive mechanical ventilation.
• Compared MPdyn and MPstd using univariable regression and Bland-Altman analysis across varying I:E ratios, PEEP, and tidal volumes.

Main Results:

• The MPdyn equation demonstrated a strong correlation with MPstd, with R² ≥ 0.98 across all tested conditions.
• Bland-Altman analysis revealed no statistically significant difference between MPdyn and MPstd.
• The mean difference in patient power between the two equations was minimal (0.04 J/min, p=0.42).

Conclusions:

• The developed MPdyn equation provides a reliable and easily calculable method for assessing mechanical power at the bedside.
• Physicians can readily use MPdyn for patients on volume control mode mechanical ventilation.
• This tool facilitates closer monitoring and potential adjustment of ventilator settings to minimize lung injury.