RESPIRATORY ISOLATION OF PATIENTS WITH SUSPECTED PULMONARY TUBERCULOSIS IN AN INNER-CITY HOSPITAL

Objective: To identify clinical factors that predict which patients pr esenting to the ED with pneumonia will require respiratory isolation f or suspected tuberculosis and to evaluate a protocol for rapid identif ication of patients at risk for pulmonary tuberculosis (PTB). Methods: To identify potential clinical indicators of PTB, a case-control stud y was performed using patients admitted to an urban teaching hospital with the ED diagnosis of pneumonia (derivation sample). These predicto rs were then evaluated in a separate prospective observational study o f 103 patients admitted to the same institution from July 1994 to Febr uary 1995. Adult patients with the admitting diagnosis of pneumonia we re admitted to a respiratory isolation bed if they met 1 of the follow ing criteria: 1) HIV-positive or unknown HIV status with a history of injection drug use; 2) chest x-ray consistent with PTB; or 3) pneumoni a with 1 of the following: PPD conversion within 2 years, recent expos ure to PTB, previous PTB, or hemoptysis, Patients who did not meet iso lation criteria were admitted to the medical ward and had a PPD and an ergy panel placed. Those who were anergic or PPD-positive were transfe rred to respiratory isolation. Results: Predictor variables identified during the first study phase were incorporated into the isolation gui delines noted above. Only 36 of 50 (72%) PTB patients were admitted to an isolation bed during this phase. During the second phase, 103 pati ents were admitted with the ED diagnosis of pneumonia-rule out PTB; 22 patients (22%) were culture-confirmed positive for PTB. The guideline s predicted PTB as follows: sensitivity, 0.96 (95% CI, 0.88-1.0); spec ificity, 0.14 (95% CI, 0.08-0.24); positive-predictive value, 0.23 (95 % CI, 0.17-0.35); and negative predictive value, 0.92 (95% CI, 0.77-1. 0). The 1 patient who Was not isolated was found to be anergic after 4 8 hours and subsequently isolated. Conclusion: Respiratory isolation g uidelines for patients admitted from the ED with pneumonia were develo ped and validated. These guidelines provide satisfactory guidance for isolation of patients at risk for PTB in a high-PTB-prevalence populat ion.