Poster
# 42
Poster |
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6th Internet World Congress for Biomedical Sciences |
Katsuya Yahata(1)
(1)University of Occupational and Environmental Health - Kitakyushu. Japan
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[Hygiene, Public Health & Preventive Medicine] |
[Occupational Health] |
Ethylene oxide (hereafter referred to as EO) is a typical chemical substance for gas sterilization and it is widely used in medical institutions. EO sterilization is applied to tubes, plastic devices, and linens, which are not suited for heat sterilization.
Because of its flammable, explosive and irritative natures, EO gas needs careful handling and management. It was also found to be carcinogenic, and IARC (International Agency for Research on Cancer) classified it as Group 1 carcinogenic to human(1). In 1977, AHA (American Hospital Association) and the National Institute for Occupational Safety and Health (NIOSH) carried out a survey on how EO was utilized in medical institutions in the U.S. As a result, it was suggested that about 75000 sterilization workers could be exposed to EO and, including other medical workers, EO exposure could influence over about 100,000 workers(2).
In this study, we conducted a survey of current EO management and its problems through questionnaires in collaboration with the medical institutions of a certain Japanese ordinance-designated city and the results are reported here.
In January 1997, we distributed a self-administered questionnaire to the total of 185 organizations among from the major hospitals in the city plus medical institutions. Of 185 organizations, 127 of them replied and 120 organizations were focused for analysis removing 7 organizations with inappropriate answers.
In the questionnaire, we asked about 1) basic information of the institutions, 2) general management, and 3) management in occupational environment. Almost all items in 2) and 3) were in the alternative questionnaire.
The results were classified in 3 groups; all medical institutions, medical institutions that operate sterilization (including EO gas or heat sterilization), and medical institutions that operate EO sterilization.
We divided the medical institutions into 5 groups according to the number of employees; less than 10, less than 50, less than 100, less than 300, over 300. They were further classified by the number of beds in order to check their characteristics.
We summarized the data on the categories of 1) employee numbers and the presence of sterilization activities, 2) the number of beds and the presence of sterilization activities, 3) the rate of EO sterilization performance by clinical department, 4) the relationship between employee numbers and the occupational health management system, and 5) management conditions at EO sterilization areas.
1. Scales of medical institutions and the rates of EO sterilization activities Table 1
The rate of EO sterilization activities of clinics employing less than 10 workers and the rate of clinics that had less than 20 beds were both about 10%. When classified by number of employees, the rate of sterilization activity in medical institutions which had more than or equal to 10 and less than 300 employees was in the order of 40%. But, when classified with the number of beds, the rate was 69% if they had more than or equal to 20 and less than 100 beds. We found that the smaller the number of beds within a set range the higher the rate of EO sterilization activities. There was a 30% difference between institutions with 20 to 99 beds and those with 100 to 500 beds.
2. Rates of EO sterilization in different clinical departments Table 2
Among clinical departments, ophthalmology departments (57.1%) and obstetrics and gynecology departments (42.9%) showed higher rates.
3. Occupational health management system Table 3-1, Table 3-2, Table 3-3
The rates of occupational health professions (OHP) appointment were 58% in institutions with more than or equal to 50 and less than 100 employees, and 80% in institutions with more than or equal to 100 and less than 300 employees.
4. Scales of medical institutions and sterilization activities Table 4
The percentages of employees engaged in sterilization were 1.6% in hospitals and 20.5% in clinics, showing that the clinics have much higher rate.
5. Review of actual conditions
1) Management of sterilization activities
Five items of the questionnaire are relevant to the management of sterilization activities. The 72% (28/39) of medical institutions limited "2: Entrance of workers to the sterilization areas", 51%(20/39) of them recommended wearing "7: Gloves", 5%(2/39) actually applied "8: Full facepiece", 31%(12/39) recommended wearing "9:
Protective clothing for sterilization activities", 90%(35/39) actually "11: Removed the sterilized items quickly".2) Daily management
Four items are relevant to this. The 33%(13/39) of them performed "10: Recording of daily work contents", 69%(27/39) carried out "17: Periodical maintenance", 18%(7/39) did "18: Measurement of EO in the working environment", and 15%(6/39) actually had attachment of "19: Material safety data sheet".
3) Occupational health education Table 5-4
The 90%(35/39) of medical institutions informed workers of the hazards related to EO ("20: Hazards notification to workers"), while 67%(26/39) provided hygiene education for those engaged in sterilization activities ("21: Hygienic education to workers engaging in sterilization activities").
6 Facilities
1) Management of gas circuit from the cylinder to sterilant Table 5-1
As far as the relevant 3 items, 49%(19/39) of medical institutions did "1: EO gas cylinder isolation", 59%(23/39) of them reported the "3: Leak from an airline from a cylinder", 49%(19/39) have set up "4:Local exhaust system in gas supply equipment".
2) Management of sterilant Table 5-2
The 72%(28/39) of medical institutions put limitations on "2: Entrance of workers to the sterilization areas" and 95%(37/39) of them used "5: Fully closed type sterilization equipment". Also 5%(2/39) experienced the "6: Leak from packing and bulb".
3) Exhaust gas process circuit Table 5-3
The 79%(31/39) of medical institutions set up "12: Exclusive exhaust system", 41%(16/39) of them reported that they experienced "15: Back-streaming of the exhaust air from outside".
4) Local ventilation and whole ventilation around the sterilantAs far as local ventilation, less than half (36%(14/39)) of medical institutions have set up "13: Local exhaust ventilation at the opening of the sterilant". Almost of all institutions (97%(38/39)) were provided for "14: Ventilation for the whole working area".
7. The relationship between occupational health management system and items of work environment Table 6
The relationship between occupational health management like assignment of occupational health professionals and the items on Table 6 was tested through Fisherīs exact probability test. In this test a work environment with dedicated OHP was compared with one that didnīt have OHP. In 3 items ("1: Gas cylinder isolation" (p=0.008), "7: Gloves" (p=0.008), "9: Protective clothing for sterilization activities" (p=0.037)), significant differences were observed.
1) Occupational safety and health management system in medical institutions
In this survey, the rates of OHP appointment were 58% and 80% and they dropped down by 5-7% in both scalesī institutions. It is not unusual to handle hazardous materials in medical institutions, and gas sterilization like EO needs a work environment management system. In fact, as shown in table 6, it was proved that the solution like assignment of OHP could improve the management.
2) Management of EO gas
Observing the present situation of gas management in the EO sterilization workplace reveals an insufficient management of the gas circuit. In Japan, EO gas is classed as a hazardous chemical, and its management specifications are defined. Workers have opportunities to enter into EO sterilization workplace, so it is clear the management of working environment in dealing with EO is necessary in the workplace.
3) Management of work and work environment in sterilization
The performance rates of recording and periodical maintenance were low. In 72% of them, workers have access into the sterilization area; this suggests high EO exposure possibility of sterilization workers.
Workers are most likely to be exposed to EO when they move sterilized instruments to aerator after the sterilization in order to remove residual EO on the instruments. In most medical institutions, the moving from sterilizer to aerator is performed manually. Concentrated residual EO is attached to sterilized instruments and, thus, sterilization workers are much likely to get exposed to residual EO(3,4). Now, we have organizational problems based on the present survey.
Generally, many Japanese medical institutions still didnīt set up sufficient occupational health management system regarding EO sterilization. Also, a significant relationship was observed between either-or indicators for safe EO sterilization performance and the set-up level of occupational health management system.
1) Medical institutions still havenīt set up sufficient occupational health management systems.
2) The assignment of an OHP and health supervisor improved several items of management, and it was observed that improved occupational health management system contributes to the improvement in their solutions.
3) The large number of cases of lax safety management of gas cylinders is a serious problem.
4) It was suggested that itīs necessary to set up a sufficient occupational health management system for the safe operation of EO sterilization and minimize the influence on the peripheral environment.
This study was funded by the Ministry of Labour from 1997 to 1998.
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[Hygiene, Public Health & Preventive Medicine] |
[Occupational Health] |
