Reflection of CO2 laser radiation from laser-resistant endotracheal tubes

To assess the possibility of indirect damage by CO2 laser reflection from specialized or modified tracheal tubes, four different tracheal tubes were studied. They were (1) a Rusch red rubber tracheal tube wrapped with 3M No. 425 aluminum foil tape, (2) a Rusch red rubber tracheal tube wrapped with Venture copper foil tape, (3) a polyvinylchloride tracheal tube wrapped with Laser-Guard protective coating, and (4) a Mallinckrodt Laser-Flex tracheal tube. The tracheal tubes were straightened and centered within cardboard cylinders and the laser set to 40 W was aimed to reflect from the tracheal tubes onto the cardboard. The times to combustion perforating the cardboard cylinders because of laser reflection were 1.41 +/- 0.54 (mean +/- SD), 1.73 +/- 0.93, 3.70 +/- 2.18, and 9.26 +/- 3.40 s for tracheal tubes 1, 2, 3, and 4, respectively. The differences between the times to combustion with tracheal tubes 3 and 1, 3 and 2, 4 and 1, 4 and 2, and finally, 4 and 3 were statistically significant. We conclude that the Laser-Guard-wrapped polyvinylchloride tracheal tube and the Mallinckrodt Laser-Flex tracheal tube were less reflective of incident CO2 laser radiation than the copper or aluminum-foil-wrapped red rubber tracheal tubes.