Strain, strain rate, and mechanical power: An optimization comparison for oscillatory ventilation.

Area of Science:

• Biomedical Engineering
• Respiratory Physiology
• Computational Fluid Dynamics

Background:

• Mechanical ventilation is crucial for respiratory support but can cause ventilator-induced lung injury (VILI).
• VILI is linked to regional strain, strain rate, and excessive mechanical power delivered to the lungs.
• Optimizing ventilator waveforms is essential to mitigate VILI risks.

Purpose of the Study:

• To evaluate the optimization potential of mechanical ventilator waveforms.
• To explore the use of multiple simultaneous oscillatory flow frequencies.
• To minimize VILI risk factors: regional strain, strain rate, and mechanical power.

Main Methods:

• Simulations of oscillatory flow and gas transport were conducted.
• A computational model with anatomically derived airway segments and viscoelastic acini was used.
• Model simulations included both healthy and injured lung conditions.

Main Results:

• Single-frequency waveforms optimized regional strain or strain rate.
• A combination of multiple simultaneous frequencies minimized the mechanical power objective function.
• Multifrequency ventilation showed potential for reduced regional mechanical power compared to single-frequency ventilation.

Conclusions:

• Multifrequency oscillatory ventilation may offer advantages over single-frequency approaches.
• This approach has the potential to reduce mechanical power and subsequently lower VILI risk.
• Simulation results highlight the promise of multifrequency ventilation for lung protection.