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Engineering control to prevent the spread of tuberculosis among health care workers in Thailand.

Jensen PA; Uthaivorawit W; Garrett D; Zuber P; Limpakarnjanarat K
American Industrial Hygiene Conference and Exposition, May 9-15, 1998, Atlanta, Georgia. Fairfax, VA: American Industrial Hygiene Association, 1998 May; :18
After decades of declining incidence, tuberculosis (TS) is once again a major public health problem. From 1990 through 1994 the annual number of patients with TB at a hospital in Thailand increased from 257 to 455, largely related to an increase in HIV + TB cases. A separate study of health care workers (HCWs) at this time showed a pattern of higher tuberculin skin test (TST) positivity among persons working in direct contact with patients and who had been employed for $1 year. These results suggest that HCWs are at risk of M. tuberculosis infection (i.e., TST positivity) that may be related to occupational exposure. Three hospitals In Chiang Rai District were surveyed. The path of the patient was followed through each hospital (inpatient and outpatient) along with all diagnostic procedures. Ventilation measurements, architecture, and general observations were noted. This project is focused on implementing interventions to reduce the risk of nosocomial transmission of M. tuberculosis and to reduce the development of active TB disease among HCWs. The general infection control program with specific engineering controls is reported here. The challenge was the development of inexpensive, low maintenance engineering controls that were easy to implement by developing countries. The following recommendations were made. All outpatient TB activities should be consolidated into one area rather than having infectious TB patients walking throughout the hospital. The general TB ward is of open construction and should be so maintained. An exhaust ventilation system serving two multi-patient and two single-patient negative pressure isolation rooms was designed and is currently being installed at a cost of less than $3000. Class I biological safety cabinets were evaluated (face velocities of 35-400 ft/min were observed) and recommendations made to modify airflow rates. Bronchoscopy is an extremely high-risk procedure. Ventilation for this bronchoscopy room should be designed to provide directional airflow from the HCW to the patient and out of the room. In addition, the system should also minimize transmission to other areas within the surgical suite. Other recommendations were made for maximizing air exchange rooms, counseling rooms, radiology, waiting rooms, and other areas of the hospital.
Respiratory-system-disorders; Health-care-personnel; Infectious-diseases; Infection-control; Disease-control; Disease-transmission; Engineering-controls; Ventilation-systems; Exhaust-ventilation; Environmental-control-equipment; Public-health; Health-care-facilities; Pulmonary-system-disorders; Lung-disease; Air-flow; Air-pressure; Air-quality-control; HIV
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American Industrial Hygiene Conference and Exposition, May 9-15, 1998, Atlanta, Georgia
Page last reviewed: April 1, 2022
Content source: National Institute for Occupational Safety and Health Education and Information Division