Particulate Evacuation Under NPWT: Bench Evaluation of a Multilayer Foam Prototype Versus Commercial Dressings in a Simulated Exudate Model.

Negative pressure wound therapy (NPWT) is widely used to facilitate healing by improving local perfusion, reducing edema and controlling exudate. The porous foam dressing is central to NPWT effectiveness, however, its performance in viscous, particle-rich exudates remains challenging. Standard industry tests often rely on protein-free aqueous solutions, which overlook the complex rheology and particulate load of real wounds. This study reports a bench evaluation of a multilayer foam prototype compared with three commercial dressings under NPWT, using a simulated viscous exudate with suspended particles. We recorded 60-min drainage curves and quantified effluent turbidity as a simple, interpretable proxy for particulate transport, summarised as percentage of input turbidity recovered. The mass-based endpoint (percent solid matter recovered) showed the same ranking as turbidity. At -75 mmHg, the prototype recovered 31.6% of input turbidity, exceeding commercial foams (≤ 9.7%). At -125 mmHg, particulate recovery decreased across all dressings (≤ 9.1%). A matrix-only control indicated that commercial effluents, particularly at -75 mmHg, clustered near background level, whereas the prototype evacuated substantially more particulate while maintaining robust fluid drainage. These findings suggest that moderate negative pressure and multilayer architecture can help preserve channel patency and reduce clogging in complex exudates. We highlight the need for test methodologies that incorporate viscosity and particulate content, and for practical guidance that links dressing architecture and pressure settings to exudate characteristics. Prospective validation, including larger-sample confirmation, particle-size distributions and ultimately clinical endpoints, is warranted.