Laser Resistance of Endotracheal Tubes I: Experimental Results of a Compound Tube in Comparison to a Metallic Tube

Abstract.

Laser-induced ignition of endotracheal tubes is a serious problem in CO₂ laser surgery of the upper aerodigestive tract. A new tube built of composite materials with a foam at its surface is protected by vaporisation of water from the wet foam. This tube and a flexible metallic tube of stainless steel were tested experimentally against the radiation of various lasers such as CO₂, holmium/YAG, Nd/YAG, Nd/YAG frequency doubled in KD*P, argon and excimer. At laser power densities of 10³ W/cm², the shaft of the metallic tube was damaged within seconds whereas the compound tube was stable for more than 2 min; the damage threshold of the new tube was found to be at 3.2×10⁶ W/cm². While the compound tube was found to be sufficiently laser resistant, the metallic tube was found to exhibit functional damage, in particular the PVC inflation conduits inside of the tube were destroyed.