Like standard endotracheal tubes, laser tubes are made of polyvinylchloride (PVC), which is flammable in the presence of oxygen and an ignition source, i.e. laser light. The PVC core of the laser tubes is therefore wrapped in two layers, one metallic foil layer which protects the actual tube from the laser light, and an outer non-reflective layer.
Three 'ingredients' are required for an airway fire, namely a substrate (ET tube), oxygen (the risk of an airway fire cleary is related to the FiO2), and an ignitor (laser light or surgical diathermy/ Bovie).
The cuff of the laser tube is not protected in any way and therefore most vulnerable to laser light. The pilot balloon contains blue dye granules which dissolve when filled with water or saline. The dyed water in the cuff serves two functions:
1. It acts as an indicator in case the cuff bursts. Puncture of the cuff from the laser beam causes the dye to spill under the cuff pressure.
2. It acts as fire prevention/ a fire extinguisher.
The cuff of the laser tube is of the high pressure- low volume design.
The tubes are used in airway laser surgery (obviously).