Today there are two different types of disposable laryngoscope blades available. They are Conventional Disposables and Fiber Optic Disposables.
Conventional blades transmit power from a battery handle through a wire to a lamp on the end of the blade. Fiber optic blades transmit light from a bulb in the handle through a light fiber to the end of the blade.
Conventional disposable blades come in two different varieties. They have either an incandescent or LED type lamp on each blade. They will work on any conventional handles conforming to ISO 7376.1-2002 specifications. Conventional battery handles have metal contacts that transmit current through a wire to a bulb or LED at the tip of each blade. They tend to be more expensive than disposable fiber optic blades because of the light source on each individual blade. This feature can also be an advantage when a blade fails to light.
LED’s have some big advantages over bulbs. On a disposable laryngoscope blade LED’s make a great deal of sense. They deliver a bright and uniform white light using less battery power while producing less heat. When you shine most flashlights on the wall, you will notice a shadow in the center of the light circle. The filament inside the bulb casts this shadow. During intubation the clinician wants an even light in their field of view. Since LED’s don’t have a filament they don’t have this shadow, and project an even and uniform light.
They also generate very little heat compared to a traditional bulb. On a standard conventional blade the bulb gets hot fast. For a routine intubation this matters little, but during a prolonged difficult intubation you risk burning delicate tissues. These last two issues were addressed by the development of glass-bundle fiber optics.
Reusable fiber optic systems eliminate the light shadow problem. They break the photons apart at one end of the light bundle and collate them together at the other without a shadow. In a traditional fiber optic blade the light transmission bundle contains as many as two thousand or more individual light fibers. This is what helps most of the light to reach the distal end, and travel around corners. With a fiber optic system the handle contains the bulb. By moving the bulb outside the mouth you also eliminate the heat problem. Unfortunately this design is not exactly what is used on most disposable fiber optic blades.
Disposable fiber optic blades don’t have thousands of tiny glass-fibers that carry the light photons. They typically use a single acrylic light transmission fiber. For this reason they don’t share all the attributes of real fiber optics. Light loss occurs around the corners and the beam of light is still often shadowed much like a conventional blade. Some of the better ones cover part or all of the light fiber to reduce dazzle. However most green system fiber optic handles still use incandescent bulbs. With only a single light fiber the shadow from the filament often still remains.
Disposable fiber optic users would also be well advised to carry two handles. The only source of light in the laryngoscope is in the handle, if it fails none of your blades will light. The only way to achieve some measure of redundancy in case a bulb burns out is to carry two handles.With an LED blade you have all the advantages of a true fiber optic system at a fraction of the price. LED’s cast no shadow, produce very little heat, and don’t require a special handle. But that’s not where the advantages end. LED’s also consume much less power and last longer. That brings down operational costs.
Another advantage of LED’s is that you can fine-tune the color temperature. Today’s LED laryngoscopes are engineered to produce a much whiter light. For a Paramedic the color temperature can be important, especially when at a Sirloin Sizzler trying to tell the difference between an epiglottis and a piece of steak.
Try comparing a disposable fiber optic blade and a disposable LED blade side by side. Shine both from nearly equal height on the table in front of you. Then overlap the light beams. The LED’s brighter whiter light will so completely overpower the fiber optic; no sign of it will remain. Which would you rather use? Many disposable blades are just stamped out. Some don’t have blunted tips. To save time and money these features are often left off. Some cut additional corners and use a plastic heel blade to handle attachment. Only the very best disposables have 100% steel-to-steel handle connections and non-traumatic tips. Some now offer color-coding so you can more quickly find the right size. Last, it is now possible to decontaminate and recycle used blades if they can be easily broken down into components.
These are the main features that distinguish today’s modern disposable laryngoscope blades. Hopefully understanding them better will help you make a more thorough comparison of disposable laryngoscope options. By intelligently comparing performance and price you can best match your equipment to your expectations.