High incidence of CO2 laser beam contact with the tracheal tube during operations on the upper airway.

Polyvinyl chloride tracheal tubes from 50 consecutive CO2 laser operations of the larynx and trachea were collected after tracheal extubation. In all cases, the helium protocol for laser operations was used, which includes the following: helium in the anesthetic gas mixture at 60% or more during laser resection (FIO2 less than or equal to 0.4); tracheal intubation with plain, unmarked polyvinyl chloride tubes; laser power density less than or equal to 1,992 W/cm2; and laser bursts of less than or equal to 10-second duration. No tracheal tube fires or airway burns occurred. The polyvinyl chloride tubes were examined for marks caused by the laser, and cuffed tubes were tested for cuff viability. Of the 50 tubes examined, 18 were noncuffed and 32 were cuffed. Although most contacts did not penetrate the tubes, 58% of the tubes showed evidence of contact with the laser as a brown mark on the tube or as a cuff leak. Cuffed tubes were more likely to incur laser contact (69%) than noncuffed tubes (39%), a significant difference (p = 0.04). Most of the cuffed tubes that came in contact with the laser sustained damage at the cuff (77%). It was concluded that the risk of tracheal tube contact with a laser beam is at least 1 in 2, that cuffed tubes are more likely to be hit with a laser beam than noncuffed tubes, and that cuffed tubes that are hit usually sustain damage to the cuff. Because no fires occurred in this series despite frequent laser contact with the tube, these data indicate that the helium protocol helps to prevent polyvinyl chloride tube fires.