Document 8pb6ZJEyLDB9Oyew5GjV8rLZ

Industrial Hygiene Digest April, 1964 IL Control of Noise-Exposure -- Noise -exposure may be reduced by: (a) Environmental control (1) reducing the amount of noise produced by the source (2) reducing the amount of noise transmitted through air or building structures (3) revising operational procedures (b) Personal protection The most satisfactory method of environmental control of noise-exposure is to control the noise at the source. Unfortunately, this is not always possible. When the amount of noise produced by the source cannot be sufficiently reduced, a combination of control methods may be required to conserve hearing. HI. Measurement of Hearing-- A hearing conservation program should include: (a) pre-employment and/or pre-placement hearing tests, and (b) routine periodic follow-up tests These tests of hearing are the most important part of a hearing conservation program. They provide a record of the initial status of an employee's hearing and make it possible to follow any subsequent changes in hearing ability.. Pre.employment and follow-up tests help to identify persons who may be highly susceptible to noise-induced hearing loss. Test and retest results will show whether the conservation program is effective or not. Even when noise, exposures are not severe enough to warrant a hearing conservation program, it is desirable to test hearing systematically as part of routine physical examinations. Hearing tests are as important and as necessary as tests of vision, or any of the tests which accompany a physical examination. The statements made in the guide are based on both clinical and industrial experience, and on knowledge gained from research. Included are a summary of basic information about hearing loss and noise-exposure, a broad outline of a hearing conservation program, and a discussion of procedures recommended for executing the program. If you would like more specific information about conservation of hearing in noise, please commun icate with the Research Center of the Subcommittee on Noise at 327 South Alvarado Street, Los Angeles, California, 90057. Regarding the discussion of a change in the Standard Reference Threshold in Industrial Hygiene Foundation Engineering Series, Bulletin No. 5, recommended procedures are outlined in this guide for relating 1951 American Standards Association and 1963 International Standards Organization Standards. INDUSTRIAL MEDICAL PRACTICE 323 Asepsis in the Operating Theater. W.H. Cockcroft and F. R. C. Johnstone. Can. Med. Assn. J. 90, 659-662 (March 14,1964). In the investigation of several blood stream infections following open-heart surgery, sutures and other material that had been exposed and handled in the sterile field were examined bacteriologically. One hundred and seventy-five open-heart operations were carried out during the study period and a high percentage of the specimens cultured yielded viable staphlococci and diphtheiwds. Glove powder, textile fibers, and skin squames were found in the dust collect ed in the room during the operations and staphylococci were frequently recovered from this source, and from the floor. Although the air supply to the theater appeared to be of good quality, it is suggested that air currents within the room had caused dissemination of this foreign material and had probably contributed to wound infections. -- Authors' abst. 03121407 6.