Phantom system for endotracheal tube cuff seal testing during mechanical ventilation

Leakage of orogastric secretions past endotracheal tube (ETT) cuffs contributes to ventilator-associated pneumonia (VAP), yet in vivo tracheal seal testing is impractical, requiring phantom evaluation. As the rigid cylinder specified in EN ISO 5361:2023 does not adequately represent in vivo airway conditions, a benchtop cuff seal testing system was developed incorporating a tracheal model, lung model, mechanical ventilation, and automatic cuff pressure control. A rigid cylinder and a bio-inspired tracheal model with tissue-like mechanical properties were evaluated using five high-volume low-pressure (HVLP) polyvinyl chloride (PVC) cuffed ETTs and five polyurethane (PU) cuffed ETTs, with and without mechanical ventilation, and with and without automatic cuff inflation. For PVC cuffed ETTs, fluid leakage rate was highest in the cylinder phantom compared with the bio-inspired phantom, ~ 30% lower without mechanical ventilation and ~ 50% with mechanical ventilation (both p < 0.001). In contrast, PU ETTs exhibited minimal leakage. Long-term testing revealed intracuff pressure decay over 48 h at 37 °C for both PVC (12.24 ± 1.13 cmH2O) and PU (9.06 ± 1.00 cmH2O) cuffed ETTs, while automatic cuff pressure control further reduced leakage for PVC ETTs. The bio-inspired phantom revealed sealing behaviours not captured by cylinder testing, supporting clinically relevant evaluation of ETT sealing performance and cuff materials.