In this article, Alvarado et al described a clinical trial that included a microbiologic assessment of the ability of the Slide-On® EndoSheath® Technology (Medtronic ENT, Jacksonville, FL) to provide protection against bacterial contamination of flexible nasopharyngoscopes. Three 30-mm Olympus nasopharyngoscopes (ENF Type P4, Olympus America, Melville, NY) were used while covered with an EndoSheath® barrier to examine the nasopharynx and larynx of 100 different, randomly selected patients. The surface of the head and shaft of each nasopharyngoscope was wiped to obtain two samples for culture at each of the following times: before application of the EndoSheath® Technology and the endoscopic examination, immediately after the examination and removal of the EndoSheath® disposable, and after a disinfection procedure consisting of the following steps: vigorous wiping of the endoscope with an enzymatic detergent, rinsing with running tap water, drying with gauze, wiping with gauze soaked in 70% ethanol, and air drying in a vertical position. All samples were plated on 5% sheep blood agar and incubated for 72 hours at 37˚. Bacterial colony types were enumerated and identified by using standard methods. The study also included leak testing of the 100 used disposable sheaths removed from the nasopharyngoscopes and of 20 unused sheaths taken from the clinic inventory. The barrier integrity of the EndoSheath® Technology was assessed by using a pressure decay system (138 ± 2 inches of water [5 lb per square inch]).
Bacteria grew in cultures of 16 head and 6 shaft samples obtained before the endoscopic procedure, 13 head samples and 1 shaft sample taken immediately afterward, and no samples obtained after the disinfection procedure. The contamination found was low level (2 to 100 colony-forming units) and due primarily to skin commensals, mainly coagulasenegative Staphylococcus and Bacillus species. One sample was positive for Staphylococcus aureus; none showed gram-negative bacilli or fungi. None of the 120 used or new sheaths lost barrier integrity on leak testing. Alvarado et al noted that not a single leak or tear had been detected in the total of 755 sheaths in their study and all previously reported clinical trials in which the EndoSheath® Technology was used.
In light of their findings, the researchers concluded that use of the EndoSheath® Technology followed by proper cleaning and intermediate disinfection with 70% ethanol can provide a safe, patient-ready nasopharyngoscope, with reliable protection against contamination by virulent bacteria pathogens such as methicillin-resistant Staphylococcus aureus, Pseudomonas aeruginosa, and mycobacteria species and by viruses likely to be present in the respiratory tract. Alvarado et al also suggested that the acquisition costs of disposable sheaths would be off set by avoidance of high-level reprocessing of flexible endoscopes, which is expensive and may expose health care workers to toxic disinfectants; by reductions in endoscope downtime; and, possibly, by a decrease in costs associated with inadequate high-level reprocessing practices.
