Simulation of Central Airway Gas Flow Dynamics During Conventional and Multifrequency Ventilation

Area of Science:

• Respiratory physiology
• Computational fluid dynamics
• Mechanical ventilation

Background:

• Acute respiratory failure often necessitates mechanical ventilation.
• Lung heterogeneity can lead to uneven ventilation and strain during conventional mechanical ventilation (CMV).
• Multifrequency ventilation (MFV) is a novel technique aiming for more uniform lung distribution.

Purpose of the Study:

• To computationally simulate and analyze gas flow dynamics in a porcine airway model under MFV versus CMV.
• To evaluate the impact of MFV on ventilation distribution, parenchymal strain, and gas mixing.

Main Methods:

• A computational lung model of a porcine central airway tree (trachea to 5th generation) was developed.
• Dynamic boundary conditions were applied for volume-controlled CMV (0.27 Hz) and MFV (0.27 Hz + 3.5 Hz + 7.0 Hz).
• Gas flow, pressure dynamics, and airflow patterns were simulated and analyzed in time and frequency domains.

Main Results:

• MFV simulations showed increased asymmetric flow (pendelluft) at end-inspiration and end-expiration compared to CMV.
• MFV augmented inlet-outlet phase differences for both pressure and flow.
• These findings suggest enhanced gas mixing within the simulated lung model under MFV.

Conclusions:

• MFV may promote more efficient ventilation by enhancing gas mixing.
• The study provides computational insights into the potential benefits of MFV for mechanically ventilated patients.
• Further research is warranted to validate these findings in clinical settings.