More than just intubation, a short fiberoptic scope can check for edema, infection, burns, or foreign bodies. And single use and sheathed scopes are bringing the usefulness of this technology back into the ED.
The need for fiberoptic intubation in the ED is infrequent. Its utility for rescue intubation has been diminished by the expanding use of video laryngoscopes, but fiberoptics are still ideal in cases of angioedema, diverse causes of laryngo-tracheal pathology, and for other scenarios when RSI is contraindicated. As ENT consultants have retreated from covering EDs, the need for nasoendoscopy by ED physicians to assess the upper airway has increased. In addition to checking the airway in cases of edema, infection, burns, and foreign bodies, a flexible scope is very useful for visualizing the trachea after replacing a tracheostomy tube or its inner cannula.
Flexible fiberoptic devices have historically had logistic problems with cleaning, sterilization, cost, and frequent breakage. Fiberoptic devices can be grouped into long scopes used for intubation (generally 60 cm), and short rhinolaryngoscopes for nasoendoscopy (30 cm). There are also mid-length scopes (~36 cm) that could potentially be used for intubation, assuming a tracheal tube is partially inserted initially. Articulating a flexible scope must be done outside of a tracheal tube, so to navigate a scope into the trachea it must be long enough to extend beyond the tube (generally 30-34 cm, but the tube can be cut down when going through the mouth).
Long scopes have a life and death utility on rare occasions, but short scopes have many more opportunities for use. For starters, the short scope is much easier to use. Flexible scopes must be held out to length to allow effective manipulation of the scope with turning of the wrist, and this is challenging using a 60 cm long instrument. The shorter scopes are also vital in that they allow ED physicians frequent practice. Numerous studies have shown that clinicians taught fiberoptics with a short scope can effectively intubate over a long scope. Additionally, since short scopes generally do not have a working channel, they are far easier to clean and reprocess.
Cleaning and reprocessing using cold sterilization is problematic for EDs on several levels. In December 2009, the FDA questioned the safety of some Steris machine cleaning systems and many hospitals moved away from this method of cleaning. Machine systems also can easily break scopes if the scope is not loaded properly. Cold sterilization solutions using simple immersion (glutaraldehyde and other chemicals) require a venting hood or vapor barriers to be in compliance with workplace safety rules. Scopes with working channels (i.e., all intubating scopes that are 60 cm long) require not only cold sterilization of the scope, but also wire brushing and flushing of the working channel to prevent transmission of Pseudomonas, TB, HIV and other pathogens.
Two new fiberoptic devices have the potential to dramatically expand the use of flexible fiberoptics in EDs. The first of these is a single-patient use, inexpensive intubating scope; the second is a sterile sheath that dramatically changes the way flexible fiberoptics are used between patients, eliminating the need for cold sterilization, or sending the scope out of the department for processing.
The Ambu A-Scope is a single patient use, fully articulating, chip-on-a-stick videoscope [bottom right]. Traditional fiberoptics use glass fibers that collectively focus on an eyepiece; to display this image on a monitor a separate clip-on camera must be attached to the eyepiece. Video scopes like the A-Scope use small digital chips attached directly at the distal end of the scope, and the video signal is electronically conducted up the scope to a monitor (i.e., there is no eyepiece). The A-scope combines a 60 cm scope (with a simple articulating lever) and a small, simplified, plug and play video monitor. As with any scope, using a monitor is far easier than a monocular eyepiece and it is ideal for supervising residents. The company sells the reusable video monitor with a package of single-use scopes, making the unit cost approximately $200. Compared to the costs of a traditional scope (~$10,000 initial price) and a sterilization machine, chemicals, labor, and repair costs, several studies have shown this is more economical to use the A-Scope than cleaning and reprocessing a traditional long fiberscope. The image resolution, contrast and color of the A-Scope is not equivalent to the image quality of a fiberscope or a high-end video bronchoscope, but for intubation it is more than adequate. I have used the A-Scope in my cadaver courses in Baltimore for more than a year and most operators have found it very easy to manipulate. The initial version had a problem with the shape of the distal lenses (making it susceptible to secretions), but the current product works well. The outer diameter of the A-Scope (~5 mm) is larger than some intubating bronchoscopes, but this decreases the gap between the scope and tube, making tube insertion into the trachea smoother. It is still recommended to rotate left-bevelled tracheal tubes 90-180 degrees counter-clockwise (leftward) off the scope to prevent the tip of the tube (due to the gap between the tube and scope) from catching the right side of the laryngeal inlet at 14-16 cm. Tube rotation is not necessary when using a ski-tipped, symmetric beveled tracheal tube (i.e., Parker Medical Flex-It tube).
Vision Sciences manufacturers a variety of fiberoptic and video endoscopes including short rhinolaryngoscopes and long intubating scopes. the endosheath is a sterile, disposable microbial barrier that covers the endoscope, preventing patient contact [top]. Their EndoSheath technology is truly unique and adaptable to not only for Vision Sciences short and long instruments, but also other manufacturers (Olympus, Pentax, Storz, etc). At the distal end of the sheath is an optical quality lens that does not compromise the quality of view. The proximal end of the sheath has a rubberized hub that grips the proximal end of the endoscope. A distinctive soft click is felt when fully attached. The sheaths come in boxes of ten individually wrapped, sterile packages and cost approximately $10. We have used these in our ED with a large EM residency program for almost two years without any problems. The scope is checked via the eyepiece prior to use (to make sure the view is clear), and then the sheath is slid over the scope. After use, the sheath is removed by pushing the hub off the scope, and sliding the remainder of the sheath off the scope. If a vacuum has formed with the proximal hub or there is any difficulty in removing the sheath, a drop of alcohol from a wipe can be placed into the gap between the hub and scope, breaking the seal. Some clinicians use an alcohol swab to wipe the scope down after sheath removal, but this is not required. Microbial studies have demonstrated that the EndoSheath system is cleaner than traditional processing of endoscopes, and in my experience the patient appreciates seeing a sterile cover placed on a scope prior to undergoing nasoendoscopy. Endosheaths are available to fit numerous different models of endoscopes, even intubating long scopes. Sheaths for the long scopes are offered with an integrated working channel built directly into the sheath (allowing air insufflation, suctioning, or administration of topical anesthetics). EndoSheaths eliminate the need to send a flexible scope out of the department for cleaning and reprocessing. By eliminating machine sterilization they can increase the lifespan of a scope and minimize breakage. Your scope can be used from patient to patient simply by changing the sheath, eliminating any delays in patient care.
Endoscopic evaluation of the airway should be part of your ED practice. It requires only a few minutes of time, is well tolerated (with proper preparation), and lets you better assess airway pathology. Occasionally you can save someone’s life using endoscopic intubation and avoid a surgical airway. Perhaps most of all, it demystifies airway anatomy and I believe makes ED personnel far better airway managers. Logistical hurdles should no longer keep your department from acquiring and using flexible endoscopes.
Disclosure: Ambu has provided Dr. Levitan with Ambu A-Scopes for use in his Baltimore cadaver airway courses; he has also been a consultant for Ambu on supraglottic airways. Vision Sciences has provided Dr. Levitan with endoscopes and sheaths for his airway workshops.
Dr. Levitan teaches emergency medicine at Jefferson Medical College and at the Univ. of Maryland and helps run a monthly airway management course involving specially prepared cadavers: jeffline.jefferson.edu/jeffcme/Airway