气态甲醛暴露对医学生主观症状及肺功能的影响

Effects of gaseous formaldehyde fluctuating exposure on medical students’subjective symptoms and pulmonary function

目的调研解剖实验室气态甲醛浓度波动情况,评估气态甲醛暴露对医学生主观症状及肺功能的影响。方法采用气态甲醛检测仪测量不同物理通风时间、实验室中央气态甲醛浓度。从参加解剖操作的1004名学生中随机抽取252名二年级医学生作为调查对象,并在其中随机抽取77名医学生进行肺功能评估。在解剖操作前、中及结束后以问卷调查形式调研医学生暴露于气态甲醛后的主观症状。于解剖操作前、结束后分别进行肺功能检测以评估气态甲醛暴露对医学生肺功能的损害程度。结果实验室内气态甲醛浓度随通风时间延长而下降(P<0.05),但始终高于职业卫生标准(0.50 mg/m3)。解剖台上方气态甲醛浓度(0.43~2.89 mg/m3)明显高于同时间点实验室中央气态甲醛浓度(0.34~2.31 mg/m3)(P<0.05)。解剖至胸腹腔区域时的气态甲醛浓度(0.67~2.89 mg/m3)显著高于同时间点解剖至浅筋膜(0.50~2.13 mg/m3)及背部深层时的气态甲醛浓度(0.34~1.48 mg/m3)(P<0.05)。医学生的眼痒、鼻塞、流涕、呼吸困难、头痛和精神不振等主观症状检出率随操作次数延长而明显上升(P<0.05),操作结束后呈显著下降趋势(P<0.05)。第1秒用力呼气率、第1秒用力呼气量、呼气峰流量、呼气中期流量和25%肺活量时最大呼气流量在操作结束后较操作前均下降(P<0.05)。结论现有物理通风设施难以将气态甲醛浓度降至安全阈值以下,高浓度气态甲醛暴露致使医学生主观症状显著升高且伴有继发性肺功能损害。

OBJECTIVE To determine the concentration of fluctuating gaseous formaldehyde in an anatomy laboratory and to investigate its effects on the subjective symptoms and the lung functions of medical students working there. METHODS To measure the levels of formaldehyde gas at different physical ventilation times at the center of the study laboratory by the gaseous formaldehyde detector. A total of 251 of second-year medical students were randomly selected from 1004 students participating in the anatomy operation as the survey subjects, 77 medical students were randomly selected for lung function assessment. The subjective symptoms of the medical students exposed to this gas were investigated via questionnaire surveys before, during and after the dissection operation. The probable lung function damages caused by the exposure before and after the operation were also measured using various parameters. RESULTS The concentration of gaseous formaldehyde decreased with an increase in the ventilation time(P<0.05),but it was always higher than the occupational health standard(0.50 mg/m^3). The gas concentration above the dissecting table(0.43-2.89 mg/m^3) was significantly higher than that at the center of the laboratory(0.34-2.31 mg/m^3)(P<0.05). The levels of the gas in the thoracic and abdominal cavities(0.67-2.89 mg/m^3) were significantly higher than those in the superficial fascia(0.50-2.13 mg/m^3) and deep layer of the back(0.34-1.48 mg/m^3)(P<0.05).When compared with that at the pre-operative period, the prevalence of most subjective symptomssuch as itchy eyes, nasal congestion, runny nose, dyspnea, headache, and lack of energy increased significantly during the operation and decreased thereafter(P<0.05). After the procedure, forced expiratory volume 1(FEV1)/forced vital capacity(FVC), FEV1, peak expiratory flow(PEF), FEF25%-75%, maximum expiratory flow 25%(MEF25%), and FEF50%-75% were found to be lower in comparison with the corresponding values recorded before the operation(P<0.05). CONCLUSION Existing physical ventilation facilities are difficult to reduce the concentration of gaseous formaldehyde below the safety threshold. Exposure to ultra-high concentrations of gaseous formaldehyde caused a significant increase in subjective symptoms of medical students with secondary pulmonary function impairment.