Evaluation of endoscope sheaths as viral barriers

Objectives: Evaluate ENT endoscope sheaths as barriers to virus passage. St udy Design "Defective" sheaths covering an endoscope were, challenged with virus to determine how many virus particles could be recovered from the end oscope, Methods: Sheaths with small laser-drilled holes (2 to 30 mu m) were challenged with high-titer virus suspensions (10(8) viruses/mL). The insid e of the sheath and the endoscope were separately rinsed to recover any vir us that penetrated through the hole in the sheath. In an attempt to assess the possible importance of holes in the sheaths, a sequential test was cond ucted with an initial virus challenge outside a defective sheath (30-micron hole in the sheath), after which the possibly contaminated endoscope was r emoved and inserted into a second defective sheath (with a 20-micron hole a t the same location) to determine whether the contaminating virus would pas s outward through the second sheath. Results: Small volumes of virus-contai ning fluid penetrated through the hole, e.g;, 500 virus particles passed th rough one of three 30-mu m holes. A significant fraction of those virus par ticles was occasionally found on the endoscope after removal from the sheat h, Similar results were obtained with sheaths that had small tears (34-84 m u m in length, from punctures with fine wires), Although some virus penetra tion could occur during the initial challenge contaminating the endoscope, no virus was detected passing outward through the second sheath. Conclusion s: Use of a sheath combined with intermediate level disinfection should pro vide a safe instrument for ENT endoscopy.