A recent publication by Chuang et al. carefully characterizes the content of smoke (or plume) created from laser hair removal.1 At the University of California, Los Angeles, discarded terminal hairs from the trunk and extremities were collected from two adult volunteers. The hair samples were sealed in glass gas chromatography chambers and treated with either an 810-nm diode laser (Lightsheer, Lumenis) or 755-nm alexandrite laser (Gentlelase, Candela). During laser hair removal (LHR) treatment, two 6-L negative-pressure canisters were used to capture 30 seconds of laser plume, and a portable condensation particle counter was used to measure ultrafine particulates (less than 1 mcm). Ultrafine particle concentrations were measured within the treatment room, within the waiting room, and outside the building. The laser plume was then analyzed by gas chromatography–mass spectrometry (GC-MS) at the Boston University department of chemistry.
Analysis with GC-MS identified 377 chemical compounds. Sixty-two of the compounds exhibited strong absorption peaks, of which 13 are known or suspected carcinogens (including benzene, ethylbenzene, benzeneacetonitrile, acetonitrile, quinoline, isoquinoline, sterene, diethyl phthalate, 2-methylpyridine, naphthalene carbonitrile, and propene) and more than 20 are known environmental toxins causing acute toxic effects on exposure (including carbon monoxide, p-xylene, phenol, toluene, benzaldehyde, benzenedicarboxylic acid [phthalic acid], and long-chain and cyclic hydrocarbons).
During LHR, the portable condensation particle counters documented an eightfold increase, compared with the ambient room baseline level of ultrafine particle concentrations (ambient room baseline, 15,300 particles per cubic centimeter [ppc]; LHR with smoke evacuator, 129,376 ppc), even when a smoke evacuator was in close proximity (5.0 cm) to the procedure site. When the smoke evacuator was turned off for 30 seconds, there was a more than 26-fold increase in particulate count, compared with ambient baseline levels (ambient baseline, 15,300 ppc; LHR without smoke evacuator for 30 seconds, 435,888 ppc).
It has long been known that smoke created from electrocautery also may impose a risk on the health care worker. In 2011, Lewin et al. published a comprehensive review of the risk that surgical smoke and laser imposes on the dermatologist.2 At this time, most of the laser data was for the plume created by ablative CO2 lasers. In their review, it was stated that surgical smoke is composed of 95% water and 5% particulate matter (made up of chemicals, blood and tissue particles, viruses, and bacteria). The size of the particulate matter is dictated by the device used, with electrosurgical units creating particles of roughly 0.07 mcm and lasers liberating particles of 0.31 mcm. The size of liberated particles is important as those smaller than 100 mcm in diameter remain airborne, and particles less than 2 mcm are deposited in the bronchioles and alveoli.
Electrocautery plume is composed mostly of hydrocarbons, phenols, nitriles, and fatty acids, but most notably carbon monoxide, acrylonitrile, hydrogen cyanide, and benzene, which may have carcinogenic potential. On the mucosa of the canine tongue, the mutagenic effect of the smoke from 1 g of cauterized tissue with laser and electrocautery was equivalent to those from three or six cigarettes, respectively. Pulmonary changes also may occur. Blood vessel hypertrophy, alveolar congestion, and emphysematous changes were seen in rats after plume created from both electrocautery and Nd:Yag ablation of porcine skin. In that study, pulmonary changes were less severe in rats exposed to surgical smoke collected with single- and double-filtered smoke evacuators than unfiltered smoke.
Infection also poses a risk, with bovine papillomavirus and HPV detected in CO2 laser plume as early as 1988. In 1995, Gloster and Roenigk at the Mayo Clinic conducted a comparative study using questionnaires sent to members of the American Society for Laser Surgeons and the American Society of Dermatologic Surgery.3 The comparison groups were CO2 laser surgeons and two large groups of patients in the community with a diagnosis of warts. Analysis revealed that CO2 laser surgeons had a statistically significant greater risk of acquiring nasopharyngeal warts but were less likely to acquire plantar, genital, and perianal warts than the Mayo Clinic patient group did, demonstrating that laser plume is a likely means by which HPV can be transmitted to the upper airway, suggesting that those using lasers to treat HPV lesions are at greater risk. Staphylococcus, Corynebacterium, and Neisseria also have been detected during laser resurfacing.
Traditional surgical masks are able to capture particles greater than 5 mcm but offer no protection against particulate matter produced by electrosurgical and laser devices liberating byproducts less than 1 mcm. Laser masks or high-filtration masks provide greater protection than do standard surgical masks and are able to filter particles to 1.1 mcm; however, it has been shown that approximately 77% of particulate matter in surgical smoke is 1.1 mcm and smaller. Smoke evacuators consist of a suction unit (vacuum pump), filter, hose, and inlet nozzle. The smoke evacuator should have a capture velocity of approximately 30-45 m/min at the inlet nozzle. As the effectiveness of the smoke evacuator decreases with farther distance away from the procedure site, the current study of laser plume from LHR recommends that the smoke evacuator be placed within 5 cm of plume generation.4 In a study of warts treated with CO2 laser or electrocoagulation, smoke evacuators are 98.6% effective when placed 1 cm from the treatment site, with efficacy decreasing to 50% when moved to 2 cm from the treatment site.
As our specialty likely conducts the highest proportion of laser and electrosurgical procedures of any specialty, current recommendations for electrocautery, laser resurfacing, and LHR should include adequate air filtration and the use of high-filtration masks and smoke evacuators by the health care practitioner.
References
1. JAMA Dermatol. 2016 Jul 6. doi: 10.1001/jamadermatol.2016.2097. [Epub ahead of print]
2. J Am Acad Dermatol. 2011 Sep;65(3):636-41.
3. J Am Acad Dermatol. 1995 Mar;32(3):436-41.
4. J Am Acad Dermatol. 1989 Jul;21(1):41-9.
Dr. Wesley and Dr. Talakoub are co-contributors to this column. Dr. Talakoub is in private practice in McLean, Va. Dr. Wesley practices dermatology in Beverly Hills, Calif. This month’s column is by Dr. Wesley. Write to them at dermnews@frontlinemedcom.com .
