Performance of a plastic optical fiber stylet for tracheal intubation of a dog

We set out to establish whether a novel plastic optical fiber incorporated into an endotracheal tube (ETT) stylet could be used for intubation of a dog. A secondary objective examined the need for a direct illumination source from a laryngoscope. Lastly, the fragility of the system was tested.

An anesthetized dog was repeatedly intubated using a laryngoscope to elevate the tongue and the view of the larynx conducted through the plastic optical fiber stylet (placed within an endotracheal tube) and displayed on a television monitor. Four prototype identical stylets were tested. Repeated intubations were attempted with each stylet and graded as either successful or failed. All four stylets were tested 10 times each using a Miller 4 blade and direct illumination from the laryngoscope. Two of the four stylets were reused during an additional 10 intubation attempts using a Miller 4 blade and laryngoscope (without batteries) with only ambient light. Finally, one stylet was used for intubation after 10, 20, 30, 40 and 50 sharp 90 degree bend-and-straighten cycles using a Miller 4 blade and laryngoscope for direct illumination.

All attempted intubations were successful. However, the image quality was dramatically better when direct illumination from a laryngoscope was used than when ambient light was used. One plastic optical fiber stylet was successfully used to intubate after having been used for 20 intubations and 50 sharp 90 degree bend-and-straighten cycles. A partial lens separation occurred between the 41st and 50th bend cycle but the image remained adequate enough to successfully intubate again.

A novel plastic optical fiber incorporated into an ETT stylet can be used with a laryngoscope for intubation of a dog. Direct illumination from a laryngoscope provides a better television monitor image than when only ambient light is used. The system was durable, withstanding over 20 uses and 40 sharp bend-and-straighten cycles before a lens separation failure occurred.