Increased efficiency in evaluating patients with suspected tuberculosis by use of a dedicated airborne infection isolation unit.

Background: The resurgence of tuberculosis (TB) in the 1980s and early 1990s in the United States was also accompanied by numerous hospital outbreaks of TB and nosocomial transmission to health care workers.

Objective: To determine whether a dedicated airborne infection isolation (AII) unit improves efficiency in "ruling-out" patients suspected of having pulmonary TB. This is important because, to prevent nosocomial transmission of TB, the number and ratio of patients isolated who are subsequently found to have TB is much higher than those "ruled out" and have TB excluded.

Methods: A prospective cohort study was conducted of all patients 18 years and older admitted to respiratory isolation during 3 separate time periods before and after opening of an 26-bed AII unit in a 1000-bed, public, university-affiliated, innercity hospital.

Results: A total of 879 patients were admitted during the 3 study periods. Most were black and males (87%, 72%, respectively). The median age was 42 years, and 70% of patients included in the study were HIV positive. Among patients who "ruled out," ie, TB was excluded by having 3 negative AFB smears of respiratory specimens for TB, there was a significant decrease in time from 5.0 days in period I to 3.3 days in period III (P < .0001). In period III, patients who were admitted to rule out TB in areas outside of the AII unit in other wards of the hospital required a significantly longer period to have TB excluded: 5.9 days compared with 3.5 on the AII unit (P = .0015).

Conclusion: The decrease in isolation time after the opening of the dedicated AII unit demonstrates that a concerted effort to rule patients out by having nurses and respiratory therapists trained in tuberculosis control is efficacious and efficient and results in significant cost savings.