Journal Articles
Journal Articles
Woeltje KF, L'Ecuyer PB, Seiler S, et al. Varied approaches to tuberculosis control in a multihospital system. Infect Control Hosp Epidemiol 1997; 18:548-553.
While practices used to control nosocomial tuberculosis outbreaks have been well-described, the efficacy and outcome of routine TB control practices in non-outbreak hospital settings have not been well-documented. The authors describe TB infection control practices used in a Midwestern multihospital system and relate them to employee tuberculin skin-test (TST) conversion rates.
Data were collected from a survey sent to occupational health and infection control departments at 13 member hospitals (seven rural and six urban) of BJC Health System in Missouri and southern Illinois. Information included hospital demographics, policies regarding skin testing and TB control plans, TB case rates, and employee skin-test conversion rates. Four years of hospital records were reviewed to verify the number of TB cases at each institution. Occupational health records were checked to verify the number of employees with positive TSTs. All available negative-pressure ventilation rooms (NPVRs) were tested for air flow direction.
Four of the urban hospitals were teaching centers, one was a children's hospital, and one was a university-affiliated tertiary referral center. Hospitals had medians of 220 beds and 875 employees.
Regarding TB risk as categorized by the U.S. Centers for Disease Control and Prevention, six hospitals were in the very-low-risk category, six others were considered low-risk, and one was in the intermediate-risk category.
Administrative controls included TB control plans at all hospitals and annual TB skin-testing. All employees were tested at 10 hospitals, while three hospitals tested only selected employees. The percentage of employees tested ranged from 47% to 100% (median 82%). Tubersol was used at eight hospitals and Aplisol at five. Five hospitals allowed TSTs to be placed by a staff nurse rather than an occupational health or infection control nurse. Seven hospitals allowed staff nurses to read skin-test results. Two hospitals allowed employee self-reading.
Engineering controls included NPVRs in 11 hospitals (range was one to 37; median, nine); 10 hospitals had patient rooms with negative pressure. The two hospitals without NPVRs referred patients with actual or suspected TB to other facilities. NPVR testing with smoke-sticks revealed that 44% to 100% (median, 88%) had effective negative pressure. Ultraviolet light was used in some isolation rooms at one hospital. Portable high-efficiency particulate air (HEPA) filters were available at two hospitals.
Primary personal respiratory protection included dust-mist-fume masks at eight hospitals, HEPA respirators at three, and simple surgical masks at two. (The study was conducted prior to the CDC recommendation for N-95 respirators.) Nine hospitals had fit-testing programs, but the percentage of employees fit-tested was 0% to 40% (median, 3.6%).
TST conversion rates ranged from 0% to 1.0% (median, 0.3%). One hospital reported three conversions out of 240 employees, for a conversion rate of 1.3%. The hospital had no TB patients in the year prior to the conversions. Aplisol had been used for routine testing, but when the three converters were retested with Tubersol, only one was skin-test positive, for a corrected rate of 0.4%. For the entire system, there were 56 conversions out of 16,324 employees tested, for an annual conversion rate of 0.3%.
No association was found between conversion rates and hospital location, type of respiratory protection TB risk category, number or percentage of effective NPVRs, number of TB cases, or TB case rate, the authors point out.
They note that although most hospitals complied with CDC guidelines regarding TB control plans and employee TST, "testing practices often fell short of those suggested in the guidelines." Non-recommended practices include employee self-reading of TSTs and the use of staff nurses to place and read TSTs.
"Reliable testing and reporting methods must be in place to avoid missing or misinterpreting changes in employee conversion rates," the researchers state.
Engineering controls also varied substantially. Not all hospitals had NPVRs available, and some rooms designed for negative pressure ventilation did not function properly, unbeknownst to the hospitals. Some hospitals did not have negative pressure ventilation in all the recommended areas (emergency department, patient rooms, and pulmonary procedure rooms), making it difficult to isolate TB patients properly.
Personal respiratory protection varied widely, probably due to recent controversy over appropriate masks for TB protection, the authors surmise. Future mask use will be more uniform when N95 respirators are required by regulation, they say.
The study shows low TST conversion rates despite the variability of TB control methods. No significant differences in rates were seen among the very-low-risk, low-risk, and intermediate-risk hospitals. Those with the highest TB risk had better tracking of employee skin-test conversions and had comparably low conversion rates.
TB control policies at the 13 hospitals varied widely, which the researchers attribute to low numbers of TB patients and "little data to support any particular policy." They note that their study suggests that mask choice is not critical.
"Although good basic TB control measures need to be followed in all hospitals, it seems that extensive TB control interventions may not be warranted in areas of low TB prevalence. Instead, efforts should be focused on areas with the highest risk," they state. "What measures need to be routinely in place during non-outbreak periods remains to be determined."
Subscribe Now for Access
You have reached your article limit for the month. We hope you found our articles both enjoyable and insightful. For information on new subscriptions, product trials, alternative billing arrangements or group and site discounts please call 800-688-2421. We look forward to having you as a long-term member of the Relias Media community.