This article describes a laboratory study by Vaz et al that assessed images from a nasal endoscope (Olympus P4, Tokyo, Japan) with and without EndoSheath® Technology. The endoscope was secured to an optical bench, and a target was placed 20 mm from its tip, in the mid-range of the depth of field. The target was designed to fill the field of view when viewed with the endoscope at a distance of 20 mm. The researchers first used a spectrophotometer to measure the spectral distribution of the endoscope’s visible output with and without EndoSheath® Technology. They then asked nine experienced endoscopists blinded to whether the endoscope was sheathed to guess whether the EndoSheath® Technology was present. The endoscopists were initially shown the image with and without EndoSheath® Technology. Subsequently, on 10 separate occasions, they viewed the target while blinded to the presence or absence of a disposable sheath and used a score sheet to record whether they thought an EndoSheath® barrier was in place. The sheathing and unsheathing were done by an independent observer in accordance with a previously determined random sequence.
The spectral analysis found that application of EndoSheath® Technology had no effect on the spectrum of light emitted by the endoscope. Therefore, according to Vaz et al, any apparent difference in images from the sheathed and unsheathed instrument should not have been due to any chromatic effect. The score sheets completed by the endoscopists were reviewed to determine how many times the physicians correctly guessed that the endoscope was sheathed (or not). This analysis found that the endoscopists provided significantly more correct answers than would be expected by chance (P = 0.00052; mean, 6.8 correct answers per endoscopist; range, 4-9).
Vaz et al mentioned two principal benefits of using EndoSheath® Technology: the ability to quickly reuse nasal endoscopes in the clinic that results from the decrease in downtime necessitated by sterilization; and the prevention of contamination, especially in situations in which an endoscope must be employed outside an otolaryngology unit (for instance, in the intensive care unit or emergency room). The authors also noted the importance of following the manufacturer’s guidelines to ensure safe fitting of the disposable barrier to, and removal from, an endoscope. Vaz et al concluded that their findings suggest that EndoSheath® Technology use is associated with an optical change but that the magnitude of the change and its possible effect on clinical practice require further investigation.
