Effect of mechanical ventilation waveforms on airway wall shear

Area of Science:

• Pulmonary Medicine
• Biomedical Engineering
• Computational Fluid Dynamics

Background:

• Understanding airway wall shear stress is crucial for preventing ventilator-induced lung injury and inflammation.
• Mechanical ventilation is a life-support measure for respiratory failure in intensive care, but waveform characteristics can influence lung tissue stress.

Purpose of the Study:

• To investigate the influence of different mechanical ventilation waveforms on airway wall shear stress (WSS) and shear strain rate.
• To identify specific waveform parameters that may mitigate risks of inflammation during mechanical ventilation.

Main Methods:

• Computational fluid dynamics (CFD) analysis was employed to simulate airflow dynamics.
• Six distinct mechanical ventilation waveforms were simulated using airway geometry from the second to third generations.
• Airway wall shear stress (WSS) and shear strain rate were quantified for each waveform.

Main Results:

• The Original with Sine Inhale Waveform (OSIW) generated the highest WSS, while the Near True Sine Waveform produced the lowest WSS.
• OSIW and the Short Sine Inhale with Long Sine Exhale Waveform (SSILSEW) resulted in higher shear strain rates compared to the Original Waveform (OW).

Conclusions:

• Mechanical ventilation waveforms significantly alter airway wall shear stress and strain rate.
• Optimizing ventilation waveforms, particularly those with sine components, shows potential for reducing lung inflammation.
• Developing targeted mechanical ventilation strategies based on waveform characteristics could improve patient outcomes in intensive care.