Airflow dynamics in obese minipigs with obstructive sleep apnea

Area of Science:

• Respiratory Physiology
• Biomedical Engineering
• Sleep Medicine

Background:

• Obstructive sleep apnea (OSA) is linked to pharyngeal airway anatomical restrictions.
• The precise airflow dynamics mechanism in OSA remains largely unknown.
• Computational fluid dynamics (CFD) offers a method to investigate these dynamics.

Purpose of the Study:

• To test the hypothesis that increased pharyngeal restriction in OSA/obese minipigs leads to higher resistance and turbulence.
• To utilize CFD to model pharyngeal airflow dynamics in OSA.
• To determine if turbulence induces temporary pharyngeal airway blockage.

Main Methods:

• Five Yucatan minipigs (3 non-obese, 2 obese) underwent sleep monitoring and sedation for MRI.
• 3D pharyngeal models were created from MRI data and meshed for finite element analysis (FEM).
• CFD simulations incorporated airflow parameters to identify turbulent airflow.

Main Results:

• Obese minipigs exhibited OSA indicators (AHI=32-35), lower tidal volumes, and reduced inspiratory airflow speed.
• FEM simulations showed no turbulence in the pharynx of either group.
• A 25% increase in airflow velocity was noted at the narrowest nasal pharynx section in obese/OSA minipigs.

Conclusions:

• Despite narrower pharyngeal airways and increased airflow velocity in obese/OSA minipigs, CFD simulations did not produce turbulence.
• The study challenges the assumption that pharyngeal airway restriction directly leads to turbulence in OSA.
• Further research is needed to fully understand airflow dynamics in obstructive sleep apnea.