Clinical Options In The Delivery Of The CO2 Laser In The Tracheobronchial Tree

The clinician interested in using the CO2 laser endoscopically in the tracheobronchial tree presently has limited options due to problems in fiberoptic transmission. Three delivery systems have been used in a laboratory setting in a canine model: a CO2 laser coupler with a specially modified rigid bronchoscope (Cooper LaserSonics), a metallic waveguide (Laakmann Electro-Optics) and a polycrystalline fiber (Cooper LaserSonics). The most efficient laser delivery system for clinical application occurred with the wave-guide requiring 32 joules to create a standard 5 mm2 lesion, as compared to 54 and 184 joules for the coupler and fiber respectively. Limited bend radius with both the fiber and the waveguide limited clinical usefullness even through rigid bronchoscopes. In addition, only 60% power transmission was possible with the waveguide (bend radius of 6 cm). This loss of power was not associated with the fiber use. Waveguide and fiber transmission of the CO2 laser have the advantages of open bronchoscope systems with excellent telescopic optics. Unfortunately, due to the awkward, semi-flexible nature of the current waveguide and fiber deliver systems flexible bronchoscopes can not be utilized and the clinician is still obliged to use the laser coupler for most clinical applications.