Laser resistance of endotracheal tubes I: Experimental results of a compound tube in comparison to a metallic tube

Laser-induced ignition of endotracheal tubes is a serious problem in CO2 la ser 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 ste el 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 e xcimer. At laser power densities of 10(3) W/cm(2), the shaft of the metalli c 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 x 10(6) W/cm(2). While the compound tube was found to be sufficiently las er resistant, the metallic tube was found to exhibit functional damage, in particular the PVC inflation conduits inside of the tube were destroyed.