Laryngeal surgery using a CO2 laser: is a polyvinylchloride endotracheal tube safe?

Objective: We performed retrospective clinical analysis and in vitro testing to analyze the risks involved in laryngeal surgery using a CO(2) laser.

Materials and methods: The occurrence of adverse events during laryngeal surgeries using a CO(2) laser, the reasons for these adverse events, and the risks of laryngeal laser surgery were analyzed in 704 patients. In vitro experiments were performed to observe the tolerance of the cuffs of polyvinylchloride (PVC) endotracheal tubes to the CO(2) laser under conditions of filling water or air, different laser power levels, and different cutting patterns. The flammability of the PVC endotracheal tube under different oxygen concentrations, laser power levels, and laser cutting patterns were also studied.

Results: In the 704 patients who underwent laryngeal laser surgery, the tracheal cuff broke in 92 cases; sparks were observed in 8 cases; and dense smoke, in 27 cases during surgery. No fires or explosions occurred. The in vitro results were as follows: (1) Under the intermittent stimulation mode, the water cuff did not break, but the air cuff broke during the first stimulation. (2) Under the continuous stimulation mode, the water and air cuffs broke easily, and the water and air cuffs broke immediately when the stimulation power was greater than 8 W. (3) Under the intermittent stimulation mode, the PVC endotracheal tube burned only under conditions of pure oxygen supply and 10 W of laser power. Under the continuous stimulation mode, the tube did not burn with 5 W of laser power, regardless of the oxygen concentration used. When the laser power level reached 8 W and the oxygen concentration was greater than 50%, the tube will easily burn. When the laser power level was 10 W, the tube burned at oxygen concentrations greater than 20%.

Conclusions: Burning of the tube during laryngeal surgery using a CO(2) laser could be effectively avoided when appropriate measures were taken, such as filling the endotracheal cuff with water, maintaining less than 40% oxygen concentration, using less than 8 W laser power, and using the intermittent stimulation mode.