As electrocautery devices being increasingly used in the modern surgery worldwide, the surgical smoke becomes an inevitable health issue. The potential hazards of surgical smoke give rise to serious concern. To date, emerging study describes the chemical constituents of diathermy plume produced during various surgeries on live humans.Sagar et al.  detected low levels of benzene, styrene, ethyl benzene, carbon disulphide and methyl benzene in the plume generated during colorectal surgery.Hollmann and his colleagues  identified 11 different gases in surgical smoke collected at 2 cm from the tip of the unipolar electrocautery device during reduction mammaplasty. Among these chemical components, the concentration of 2-furancarboxaldehyde was measured 12 times outstandingly higher than the occupational exposure limit. Another group collected plumes as close as possible(< 2 cm) to the point of electrocautery pencil during laparotomy for abdominal surgery and demonstrated hydrogen cyanide (3–51 parts per million (ppm)), acetylene (2–8 ppm), and 1,3-butadiene (0.15–0.69 ppm) were existed in the plume. In addition, emerging evidence identified the chemical components during transurethral resection of prostates (TURP). One group detected sixteen chemical constituents in the gaseous plume collected from 15 cm above the end of the resectoscope, in whichcarbon monoxide has been found to be significantly high level, causing detrimental side effects to the medical operators such as headache, fatigue, and nausea. In line with previous study, another group also collected 12 smoke samples from TURP and vaporization and identified 16 main chemical constituents in surgical smoke including allene, propylene, isobutylene, 1,3-butadiene, vinyl acetylene, ethyl acetylene, mecaptomethane, diacetylene, 1-pentene, ethyl alcohol, piperylene, 1,4-pentadiene, propenylacetylene, acrylonitrile, cyclopentadiene, and butyrolactone.Later, Lin et al.  quantified five volatile organic compounds (toluene, styrene, xylene, phenol and furfural) in the smoke collected from the tip ofmonopolar electrocautery using in mammoplasty. Specially, higher concentrations of toluene were detected in patients undergoing modified radical mastectomy and in patients with high body mass index, as well as in longer duration of electrocautery as compared to partial mastectomy, low body mass index and shorter duration on electrocautery.Remarkably, a recent study collected 36 surgical smoke samples using an electrocautery surgical device in humanbreast reduction surgeries. They detected 17 different volatile organic compounds, among which acetaldehyde, ethanol and isopropyl alcohol were detected to be highly concentrated in every sample predominantly.Similarly,Sigrist et al.  identified carbon monoxide, hydrogen fluoride, sevoflurane, methane, ethane, ethylene during minimal-invasice surgery. Notably, twenty renal cell carcinoma patients undergoing transperitoneal laparoscopic radical nephrectomy was performed in Choi’s experiment. As a result of this research, five carcinogenic volatile organic compounds (ethanol, 1,2-dichloroethane, benzene, ethylbenzene, and styrene) and 13 noncarcinogenic chemical compounds were identified, suggesting that more attention should be paid to the long-term adverse effects associated with exposure to surgical smoke. All these experiments revealed theabundant chemicals in electrocautery smoke. However, most of these volatile organic compounds have been classified as carcinogens such as acrolein, acetaldehyde, acrylonitrile, benzene, cyclohexanone, furfural, formaldehyde, polyaromatic hydrocarbons, styrene, toluene and xylene.
Interestingly, harmless concentrations of chemical components were also detected in some articles. Gianella et al.  quantitatively evaluated the levels of chemicals in plume from a vessel-sealing device during laparoscopic surgery and indicated that the concentrations of methane, ethane, and ethylene in smoke were below the recommended exposure limit. In another study, sample collecting during laparoscopic cholecystectomy was performed within the breathing zone of medical staffs located near the operating table. Aldehydes, benzene, toluene, ethylbenzene, xylene, ozone, dioxins and furans were indentified. But all of them were lower than the hygienic standards allowed by the European Union Maximum Acceptable Concentration.
This is the first time to evaluate chemical composition of smoke produced during LEEP. Higher concentrations of formaldehyde and carbon dioxide were identified during LEEP as compared to before LEEP in this study. And other toxic compounds (benzene, toluene, xylene, ethylbenzene, styrene, butyl acetate, hendecane, acetone, acrylonitrile, 1,2-dichloroethane, phenol, chlorine, cyanide, hydrogen cyanide, and carbon monoxide) detected in the present study has been observed under the LMD.
It is well acknowledged that high concentration of carbon dioxide has been documented direct health effects on humans in previous research. A maximum acceptable indoor carbon dioxide concentration was 800 ppm (a 0.08% concentration) . When the concentration was higher than 20,000 ppm (a 2% concentration), carbon dioxide could cause deepened breathing. When higher than 40,000 ppm (a 4% concentration), could increase respiration markedly. When higher than 100,000 ppm (a 10% concentration), could cause visual disturbances and tremors and loss of consciousness. And 250,000 ppm (a 25% concentration) can cause death. However, carbon dioxide in the surgical smoke during LEEP was detected to be on average 0.098 ± 0.015%, beyond the maximum acceptable indoor carbon dioxide (0.08%), which was significantly higher than before the LEEP, suggesting that surgeons in this circumstance should take some useful methods to minimize carbon dioxide.
Formaldehyde was classified as a known human carcinogen. The threshold value for indoor formaldehyde concentration was 0.1 mg/m3.Short-term exposure may result in eye irritation, nausea, vomiting, headache, weakness, edema, dizziness, fatigue, and chest tightness. Long-term exposure may link to higher incidences of cancer in humans such as leukemia, even result in pregnant women fetal malformations. Our result has detected the average concentrations of formaldehyde in the surgical plume during LEEP were significantly higher than before surgery. Even if the concentration of formaldehyde was under the exposure limit (0.1 mg/m3), attention should be paid and preventive measures should be carried for gynecologists and other operating room staff members in order to minimize contact with formaldehyde and prevent excessive exposure. Moreover, the majority of the previous studies concerning the composition of surgical smoke collected the smoke sample near the tip of the diathermy pencil[20, 23]. While in our study, the gas concentration was measured directly at the height of the nose of gynecologists, which was diluted by the air. However, the gas concentration measured within the breathing zone exactly reflected the exposure of chemicals absorbed by operators in the operating room.
Besides, emerging evidence has declared that the suction devices were often ignored by operators. For example, a web-based survey examined current surgical smoke practices of local exhaust ventilators. The researchers found that only 14% of total 4533 respondents reported that local exhaust ventilators were always used during the procedures of electrosurgery. It is indispensable that the suction devices were used in the hospital and executed their protective function. Suction clearance of the diathermy plume with smoke extraction systems resulted in a significant reduction in the amount of smoke in thyroid surgery.With the use of wall suction, Wang et al.  found that fine particle inhalation significantly decreased 48% in superficial surgeries, 52% in abdominal surgeries and 65% in pelvic surgeries. In our experiment, suction devices were effectively used in the operating room, which resulted in the negative consequence.Therefore, we recommended practitioners to use suction system routinely and consistently when performing LEEP.
In addition, Zhao et al. identified 39 types of gases generated during transurethral resection of the malignant bladder tumor tissues, while only 16 types of gases during transurethral resection of benign hypertrophic prostate. The differences in the types of gases between benign hypertrophic prostate and malignant bladder tumor tissues indicated that electrosurgery of malignant tissue was probably more hazardous. LEEP is usually used to treat cervical high-grade CIN, which is potentially premalignant. Thus, we suspected that the chemical composition of smoke produced during LEEP may be less than the level of cervical cancer. And the potential hazard of gases during the surgery of cervical cancer needs to be further investigated.
In summary, the present investigation shows the relatively low levels of the most common chemical compounds in the smoke from LEEP, in contrast to these determined compounds, the average concentrations of carbon dioxide and formaldehyde in the plume were significantly higher during LEEP than before it. Although exposure of the patient in operating room to emerging chemical compounds is usually a one-time and short-term incident,awareness should be strengthened and preventive measures should be carried for surgeons having operations frequently in the operating room to protect themselves from long-term exposure. We recommend practitioners to use evacuation devices routinely and consistently when performing LEEP. However, there are few studies that detect the long-term effects of surgical smoke. Further research is required to investigate potential long-term effects on theatre staff performing LEEP.