The prevention laser induced tracheal tube fires necessitates the use of special anesthesia techniques. To assess the superiority of the Xomed (Jacksonville, FL) Laser Shield TM I tracheal tube to conventional tubes, we compared its combustibility to polyvinylchloride (PVC) and red rubber (RR) tracheal tubes.
Methods: Size 6 Xomed, Mallinckrodt (Glens Falls, NY) PVC, and Rusch (Germany) RR tracheal tubes were studied. A Cooper (Santa Clara, CA) CO2 laser and operating microscope were used to focus the laser beam perpendicularly onto the tracheal tube shafts. Five Lmin-1 of O2 flowed through the tracheal tubes which rested on wet towels in air during the study. The laser was set for continuous operation and actuated until a blow torch fire occurred or 90 seconds had elapsed. Ten trials each at 15, 17, and 20 watts were done for the three types of tracheal tubes. ANOVA and Scheffe tests were performed.
Results: The times to blow torch ignition of the PVC tracheal tubes were: (mean ± S>D>) 1.73±80, 1.76±0.73, and 1.53±0.42 seconds at 15, 17, and 20 watts respectively. For the Xomed tracheal tubes, blow torch ignition occurred at 85.93±80.80, 42.51±49.35, and 20.30±39.32 seconds at 15,17, and 20 watts, respectively. Blow torch fires of the RR tracheal tubes occurred after 24.49±2.64, 25.41±4.60, and 21.92±5.60 seconds at 15, 17, and 20 watts, respectively. The differences in the times to combustion of the PVC vs the Xomed tracheal tubes achieved statistical significance at 15 and 17 watts (P<0.05). Intra- luminal tracheal tube fires occurred after a significantly shorter time with the RR than with the Xomed tracheal tube at 15 watts (P<0.05). At 20 watts there were no statistically significant differences in the times to combustion of the three types of tracheal tubes tested.
Discussion: The Xomed Laser Shield TM I tracheal tube is fabricated from silicone with a coating containing metallic particles. Our study shows that at 15 and 17 watts, a significantly longer duration of laser actuation was required for ignition of the Xomed tracheal tube than for PVC tracheal tubes. However, at 20 watts, the time to combustion of the Xomed tracheal tube was not significantly different from that of the PVC tracheal tube. Similarly, while at 15 watts, a longer period of laser contact was required for blow torch ignition of Xomed tracheal tubes than for the RR tracheal tubes, at 17 and 20 watts there was no significant difference in time to intraluminal combustion of these tubes. Furthermore, the Xomed tracheal tube is much more expensive than the RR or PVC tracheal tubes.
Endotracheal tube fires have been shown to be the most common serious complication of laser airway surgery. In an attempt to prevent laser-induced airway fires, the Xomed Laser Shield I (XLS) tracheal tube was introduced. To assess its superiority to conventional tracheal tubes, we compared its combustibility to polyvinylchloride (PVC) and red rubber (RR) tracheal tubes.
A CO2 laser and operating microscope were used to focus the laser beam perpendicularly onto the tracheal tubes shafts. Five L min-1 of oxygen flowed through the tracheal tubes which rested on wet towels in air during the study. The laser was set to continuous operation and actuated until a blow torch fire occurred or 1 minute had elapsed. Ten trials each at 15, 17, and 20 watts were done for the three types of endotracheal tubes. The times to blow torch ignition of the PVC tracheal tubes were: (Mean+ SD) 1.7+ 0.8, 1.8+ 0.7, and 1.5+ 0.4 at 15, 17 and 20 watts, respectively. For the XLS tracheal tubes, blow torch ignition occurred at 85.9 + 80.8, 42.5+ 49.4, and 20.3+ 39.3 at 15, 17 and 20 watts, respectively. Blowtorch fires of the RR tracheal tubes occurred after 24.5+ 2.6, 25.4+ 4.6, and 21.9+ 5.6 seconds at 15, 17 and 20 watts, respectively. The difference in the times to combustion of the PVC vs. XLS endotracheal tubes achieved statistical significance at 15 and 17 watts (P<0.05). At 20 watts there were no statistically significant differences in the times to combustion of the three tracheal tubes tested. We conclude that the RR, PVC, or XLS tracheal tubes provide inadequate protection from the CO2 laser and should not be used for laser airway surgery. Wrapping the tracheal tubes with an appropriate metallic foil tape or the use of a stainless steel tracheal tube is recommended instead.