Pharyngeal Collapse: Critical Closing Pressure Simulator

The upper airway that collapses during an obstructive sleep apnea event is not blocked by a solid object — it is a flexible tube with no rigid skeleton, held open only by muscle tone against the surrounding tissue pressure. This simulator renders that tube as a deformable 3D pharynx and drives it with the actual Starling-resistor physics used in Pcrit research: a self-consistent, iteratively solved balance between the anatomical critical closing pressure, active dilator-muscle tone, the diaphragm's inspiratory drive, and any CPAP splinting pressure. Increase respiratory drive on a positive-Pcrit airway and watch flow accelerate through the narrowest point, Bernoulli-drop the local pressure below Pcrit, and snap the airway shut — then dial in CPAP and watch the same airway pop back open, which is exactly why pneumatic splinting, not sedation or muscle stimulants, is first-line OSA therapy.