New technologies offer visual, process and handling changes for operational consistency

HD technology has now become the new standard in most teaching hospitals and many community hospitals, owing to the superior overall image quality and wider viewing field. Changing from standard-definition (SD) video with a 4-by-3 aspect ratio and 780-by-1460 resolution to 16-by-9 1080p video significantly improves the quality of clinical images. This gives surgeons a greater ability to visualize anatomical details that were not possible with SD video systems.

HD technology now offers video images with dramatically superior clarity, resolution, and detail. But, at the same time, endoscopes have remained generally the same, with the rod-lens rigid endoscope remaining the predominant type used in the OR. What has changed is that the endoscope is now often considered the device that limits the video quality of HD systems. Essentially, the amount of visual information, or data, being transmitted through the imaging chain linking the object being viewed and the surgeon is limited by the component with the lowest resolution. With 1080p HD camera resolution now approaching the optical diffraction limit of today’s endoscopes, the quality of the endoscope itself becomes the limiting factor.

In the HD environment, anything that has a negative impact on the quality or performance of the endoscope’s critical functions or performance will diminish the image quality. And because HD resolution is significantly greater than SD video, any flaws in the endoscope are likely to be magnified on the resulting HD images. This places greater importance on maintaining the endoscope’s performance characteristics, and underscores the need to strongly emphasize rigorous inspection and damage prevention methods. This also increases pressure on the personnel responsible for ensuring the quality of endoscopes that are delivered to the OR.

Generally, when we think of an endoscope, we first consider the image quality. Before an image can be generated, however, light must be emitted from the endoscope then recaptured by the endoscope to transmit the image. Adequate light output is critical for a HD image quality. Light is transmitted through the endoscope by fiber optics, and these flexible hair-size glass fibers are packed inside the endoscope between the inner shaft and outer tube. By shining a low-powered light through these fibers, we can assess their condition by looking for black, grey or brown dots.

The use of a magnifier is helpful when performing this inspection to visualize each fiber. A black appearance indicates that the fiber is not transmitting any light; any fibers appearing grey or brown are damaged but are transmitting a limited amount of light. The smaller the diameter of the endoscope, the smaller the number of fiber optics it contains, and the fewer that can be damaged before image degradation occurs. Generally, we recommend replacement when 20 percent or more of the light fibers are damaged, and the endoscope has been inspected by qualified staff and deemed to be unacceptable.

The second critical function of the endoscope is to transmit images. Image transmission is accomplished by a system of lenses in a rigid rod-lens endoscope. Beginning with the objective lens and then followed by a series of rod lenses and spacers to the ocular lens, each of these lenses must transmit the image. Spacers are placed between the lenses to reduce reflection, refraction, and absorption of the image as it is transmitted through the endoscope. Compared to the fiber optic system in a rigid endoscope, the rod-lens system sustains damage more frequently. Damage is commonly caused by trauma sustained during use or from lapses in good care and handling practices.

To ensure the highest quality HD image in the OR, great care must be taken to ensure that no damage occurs to this lens system, and when it does, that it is noticed quickly. With HD video systems’ amazing resolution, any damage to the lens system will be noticeable when the scope is in use. It is the responsibility of CSPD personnel to perform final inspections prior to sterilization. This includes carefully looking through the scope at a close, well-illuminated object to check the image for any abnormalities.

The Prep and Pack staff should first clean all windows at both the distal and proximal ends with alcohol. Extra attention should be paid to the distal end because this end that is exposed to blood and body fluids. Once cleaned, the best way to inspect the endoscope is to visualize typed letters on a white background from a distance of 5 centimeters to 8 centimeters, looking at the center of the image and the entire perimeter of the image. Looking across the room through the endoscope is an inferior method of evaluating the endoscope and will often allow damage to be missed due to the distance, color shapes, and patterns that mask the damage. Inspection errors can result in major difficulties in the OR.

To prevent damage, the following practices in each phase of the endoscope’s daily cycle should be used:

Storage — considered to be any place that the endoscope happens to be while not actually in use, including the containers and the use of containers by staff and any positioning of the endoscope when not in the storage container (such as the back table, sink, etc,). It’s usually best if endoscopes have their own specific storage trays. If endoscopes are in set trays, they should have grommets that keep scopes and other equipment tightly secured. Labeling trays that contain scopes with a sign that says "Scopes! Handle with Care" can also help.

Transportation — this is inclusive of any method used to move scopes. This is another area where labeling containers that hold scopes can help. Transporting loose scopes or scopes that are in container (such as a basin) with other equipment is a common cause of damage.

Usage — all equipment handlers, including surgeons and residents, should be thoroughly trained on proper care and handling of endoscopes. Often people are not aware of just how fragile endoscopes are or how much they cost to manufacture and service. A little education can go a long way.

Decontamination — ensure that proper procedures and methods are used consistently – be sure to check manufacturer’s recommendations concerning compatible chemicals, soak times and rinsing procedures.

Prep and Pack — all appropriate inspection steps should be taken to ensure that the endoscope is functioning properly before it is packed. Typically CSPD staff should give the scope a thorough inspection that includes checking the distal window for debris, inspecting all seals, checking light fiber throughput, and taking a careful look through the scope at a close object to assess the condition of the lens system.

Sterilization — only the approved methods of sterilization should be used at any time. Incompatible sterilization methods can slowly degrade the condition of a scope, or even destroy it entirely. Check with your manufacturer if you have any questions about compatibility.

By examining each phase of the daily cycle, specific procedures and practices can be implemented to promote proper endoscope handling and processing. The goal is to consistently deliver to the OR endoscopes that are fully functional and meet all of the specifications of the manufacturer.

Because the acceptance of HD video technology in ORs places critical demands on the performance of endoscopes, any repair processes that take the endoscope out of original manufacturing specifications can have a negative impact on resulting image quality. After switching to HD video technology, a number of our customers found that the use of third parties for repair of their rigid endoscopes had a negative impact on image quality. This slow degradation in the endoscopes’ performance often reached a point where endoscopes had to be replaced.

The causes of these problems include the use of lenses that don’t meet the original specifications or even inferior quality lenses to replace the manufacturer’s lenses. Often the heat used during the repair process to loosen epoxy and open the scope degrade both seals and even the fiber optics – which will affect light transmission and can even cause leaks. For these reasons, the use of third parties for the repair of rigid endoscopes can pose a serious quality issue and a liability for both customers who have HD and those who have not yet switched to HD video technology.

Ensuring the best quality video for your surgeons and staff begins with having all members of the perioperative team work together to prevent damage to the endoscopes and other video equipment, then making sure that optimum practices are followed during every other phase of the endoscope’s daily cycle. Your manufacturer’s representatives should help you to design a plan of action to ensure this. By implementing and monitoring a plan of action to ensure the highest possible performance of your endoscopes, you can ensure that you’re getting the maximum benefit from owning an HD video system. The endoscopic image chain is only as good as its weakest link.