In a focused mode, CO2 laser energy easily cuts tissue while sealing very small vessels. It has been used as a scalpel for pulmonary resections, but does not seal terminal bronchi or larger vessels which lead to air leak and blood loss. If the laser beam is “defocused”, the same energy may be used to seal air and blood leaks by causing desiccation and melting of tissue without vaporization.
In the first group of experiments, 12 mongrel dogs were anesthetized, intubated, and ventilated. The lingula was exposed through a left thoracotomy. A 1 mm x 3 mm hole was made in the lung 1 cm away from the edge. The air and blood leaks were then sealed with an 8 Watt defocused CO2 laser beam (32 Watt per cm2).
Each tissue weld was tested and withstood 40 cm of water peak ventilation pressure without leak. Re-operation 3 weeks later, showed complete healing without air leak. Histologic examination showed a small zone of amorphous coagulated pleura and lung overlying a zone of microateleccasis. Normal lung was present within 150 microns of laser seal.
The second set of experiments was performed on 5 mongrel dogs which were anesthetized, intubated, and ventilated. The lingula was exposed through a left thoracotomy and excised by scalpel or scissor. The remaining cut surface of the lung was sealed using the method described above. Vessels and bronchi measuring 2 mm were easily sealed by this technique. Histologic examination 3-6 weeks later showed minimal destruction of remaining lung with minimal microatelectasis.
This new technique using currently available CO2 laser now appears ready for clinical trial in a controlled setting.