LASER HAZARDS

The hazards associated with laser use can be divided into four major categories: atmospheric contamination, perforation of a vessel or structure, embolism, and inappropriate energy transfer. There were 21 injuries reported to the FDA between January 1989 and June 1990: 2 minor, 12 serious, and 7 fatal.^[12] The distribution by type of injury is illustrated in Figure 67-6 .

Atmospheric Contamination: Laser Plume

Vaporization of tissue, whether by electrosurgery or laser radiation, produces a plume of smoke and fine particulates (mean size, 0.31 µm; range, 0.1 to 0.8 µm),^[13] sized within the range that is efficiently transported and deposited in the alveoli. Many individuals find the odor of this plume objectionable, and sensitive individuals have described headaches, tearing, and nausea as a consequence of inhalation. Deposition of laser plume particulates in rat lung appears capable of producing interstitial pneumonia, bronchiolitis, reduced mucociliary clearance, inflammation, and emphysema.^{[14] [15]}

Figure 67-6 Distribution of laser injury type reported to the U.S. Food and Drug Administration from January 1989 to June 1990. (Data from U.S. Food and Drug Administration: Special report: Laser safety. Laser Nurs 4:3, 1990.)

Potentially, the laser plume also may be mutagenic,^{[16] [17]} teratogenic, or a vector for viral infection. In vitro, the mutagenic potential of laser condensate is one half that of electrocautery, ^[17] and the total mutagenic potential from 1 g of tissue is comparable with that from smoking three to six cigarettes. The role of the smoke plume as a viral vector is controversial. Viral DNA has been detected in plume from condylomas^{[18] [19]} and skin warts^[20] but not from laryngeal papillomas. ^[21] Human immunodeficiency virus (HIV) was not detected in electrosurgical smoke plume^[22] in one study, and only noninfectious DNA fragments were found in a CO₂ laser plume from HIV-infected tissue pellets.^[23] Competent transmission of any viral infection by a smoke plume has yet to be demonstrated. ^[24] The laser plume does not appear to contain viable eukaryotic cells (i.e., tumor cells),^{[25] [26]} but it may contain viable bacterial spores. ^{[27] [28]} CO₂ lasers seem to produce the most smoke because of vaporization of tissue, and Nd:YAG contact probes produce much less. The most effective means of preventing dissemination of the plume is to use an efficient smoke evacuator at the surgical site.^{[29] [30]} Ordinary surgical masks efficiently filter particles only down to 3.0 µm, and special high-efficiency masks (e.g., The Protector II, Anago, Fort Worth, TX) are required to catch laser plume particulates. However, the high-efficiency masks are less effective when wet and may need to be changed periodically.