The Effects of Blood and Normal Saline on Laser-resistant Endotracheal Tube Combustion / 대한마취과학회지

ABSTRACT

The protection afforded against CO2 and KTP(potassium titanium phosphate) laser-induced combustion by six different types of tracheal tubes was evaluated. Some of them were wrapped with aluminum foil. They were compared before and after the application of human blood to their external surfaces. The difference of protective efficacy against laser between normal saline filled and air filled cuff was evaluated, too. The tracheal tubes tested were laser-resistant tubes such as Bivona Fome-Cuf (Group 1), Xomed Laser-shield 11 (Group 2) and Mallincrodt Laser Flex (Group 3) tubes. Aluminum foil wrapped Rusch red rubber (RR) (Group 4) and Mallincrodt reinforced Polyvinylchloride (PVC) (Group 5) tubes and unwrapped Baxter plain PVC (Group 6) tubes were also tested. CO2 loser set to 38W in continuous mode and KTP laser set to 15W were directed at the shaft of the tracheal tube under study, which had 5L/min. of oxygen flowing through it. The laser was actuated for 90 seconds or until combustion or melting occurred. Bivona tubes (Group 1) resulted in combustion in 5 tubes before and after blood application with CO2 laser, but unaffected before blood and resulted in combustion in 4 of 5 after blood application with KTP laser. Laser-shield 11 tubes (Group 2) offered good protection form both laser before and after application of blood except 1 case. At one case in Group 2, combustion occurred after blood application with CO2 laser. A combustion occured in 1 of 5 prior to application of blood and 5 of 5 after blood in Laser Flex tubes (Group 3) with CO2 laser, but occurred no tube with KTP laser. Wrapped RR (Group 4) and reinforced PVC tubes (Group 5) were unaffected by both laser, but application of blood to the foil wrapped tube shaft resulted in melting in 4 of 5 tubes. Unwrapped PVC tube (Group 6) resulted in immediate combustion in all tubes tested with both laser. Saline inflated cuffs were not perforated only in Group 2 and 3 in KTP laser and perforated immediately in other groups, but there was no combustion with saline in all groups. Air filled cuffs were all perforated in both laser, and combustion occurred. The presence of blood on the surface of metallic foil wrapped or special laser-resistant tracheal tubes may make laser-induced combustion more likely during airway surgery. However, the Laser-shield 11 and aluminum foil wrapped tracheal tube provided good protection from even when covered with blood. In addition, Mallincrodt stainless steel Laser-Flex tube provided good protection from KTP laser only. The saline filling cuffs served as a heat sink that will absorb the lasers energy, thus preventing combustion of cuffs.