Literature Review
Literature Review
Sutton PM, Nicas M, Reinisch F, et al. Evaluating the control of tuberculosis among health care workers: Adherence to CDC guidelines of three urban hospitals in California. Infect Control Hosp Epidemiol 1998; 19:487-493.
Centers for Disease Control and Prevention guidelines to prevent tuberculosis transmission in health care facilities recommend combining administrative, engineering, and respirator protection control measures. Data in this study are from three large hospitals employing health care workers at high risk for occupationally acquired TB infection. Two are county hospitals with high TB incidence rates, and the other is a private community hospital.
Based on the CDC guidelines, six TB control measures were assessed:
• assignment of responsibility for TB control;
• development and implementation of a TB control plan;
• provision of HCW training;
• ability to contain M. tuberculosis aerosol in isolation rooms;
• ability to reduce M. tuberculosis concentration in isolation rooms;
• HCWs’ use of respiratory protection.
Each hospital was evaluated for adherence to CDC guidelines for one year. Methods included a survey questionnaire, an inventory of TB engineering controls in rooms, and an assessment of ventilation performance.
Overall results showed that none of the hospitals completely adhered to the CDC’s six TB control measures. After TB patients were identified, HCWs were potentially exposed in general-use areas and inside treatment and isolation rooms at all three hospitals because of breaches in negative-pressure isolation, limitations of dilution ventilation, failure to maintain engineering controls, and failure to fully implement respiratory protection controls.
Only one hospital followed the CDC’s recommendation for the minimum level of respiratory protection, which, at the time of the study, was a disposable, filtering face-piece, HEPA-filter respirator for which the HCW had been fit-tested successfully. Workers at another hospital were provided with disposable dust-mist masks without comprehensive training and fit testing. The third hospital provided dust-mist respirators without fit testing, but HEPA respirators with fit testing were available for use with patients highly suspected or known to have infectious TB; however, they were not used.
"These findings indicate that the written hospital TB control policy differs from actual day-to-day practice," the authors state.
They also found that HCWs generally were not trained and counseled adequately as a TB prevention measure. Time limitations were cited as preventing "an interactive exchange of information suitable for the various educational, literacy, and language skill levels anticipated among job categories."
None of the hospitals allowed employee representatives input into TB decision making. The researchers suggest that including HCWs in developing and implementing a TB control plan could lead to "equitable and innovative approaches" to controlling exposures, improving compliance with policies and procedures, and dispelling fears of TB transmission in low-risk situations.
"Our findings underscore the need for hospitals to implement the CDC recommendations fully if all health care workers are to be protected," the authors state.
Lack of full adherence to CDC guidelines could lead to HCW exposure to M. tuberculosis aerosol and occupational infection, they point out. For example, a lapse in one control measure led to potential exposures even when another control measure was used because different controls were used to protect different groups of HCWs. An exposure may have occurred despite prompt patient identification and isolation when infectious patients were placed or had sputum induced in isolation rooms under positive pressure. Also, bronchoscopy staff inside the bronchoscopy suite had respirator protection, but HCWs outside the suite were potentially exposed because the suite was under positive pressure.
Because identifying the source of newly acquired TB infections in HCWs is difficult, the researchers say their findings support OSHA’s policy presumption that, "absent clear evidence to the contrary," new HCW infections are work-related. However, they add that hospitals’ lack of adherence to CDC guidelines does not mean that skin-test conversions are due to occupational exposures.
Nardell EA. Is a tuberculosis exposure a tuberculosis exposure if no one is infected? Infect Control Hosp Epidemiol 1998; 19:484-486.
In this editorial accompanying the article summarized above, the author says the California study does not mention skin testing or conversion rates among the hospitals’ health care workers. He is therefore "tempted to suspect that conversion rates were not excessive."
Because many components of current TB guidelines are based on expert opinion rather than science, it is not surprising that lack of adherence to one or more recommendations may not cause increased TB infection rates. He points out that TB experts agree that the greatest risk for TB transmission is the unidentified infectious case, not the identified patient in an isolation room.
The author estimates that due to lack of diagnostic tests with high negative predictive value, many TB isolation rooms are occupied by patients without TB up to 99% of the time; therefore, "less than perfect air mixing in an isolation room, a small door leak, or a respirator face-seal leak of 20% rather than 10% may make little practical difference to worker skin-test conversions . . ."
Another point of contention is the California researchers’ endorsement for OSHA’s presumption that TB acquired by HCWs is work-related. Nardell cites data from the CDC and NIOSH showing that, with certain exceptions, the current risk of TB for United States HCWs is low. In one study, HCWs had TB rates similar to the general population.
In contrast, he says the reverse is true in the developing world, where outbreaks of multidrug-resistant (MDR) TB are threatening HCWs who are not likely to be protected by expensive engineering and personal respiratory protection controls. Treating MDR-TB cases in developing countries will benefit United States HCWs as well, he says, "given the increasing contribution of foreign-born persons to TB morbidity."
The challenge is to allocate adequate resources to protect United States HCWs and to treat TB patients in poor countries "in the most effective, efficient, and ethical way," he adds.
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.