Indicators for prediction of Mycobacterium tuberculosis positivity detected with bronchoalveolar lavage fluid.

BACKGROUND: The diagnosis of active pulmonary tuberculosis (TB) remains a challenge in clinic, especially for sputum negative pulmonary TB. Bronchoalveolar lavage fluid (BALF) has higher sensitivity than sputum for detection of Mycobacterium tuberculosis (Mtb). However, bronchoscopy is invasive and costly, and not suitable for all patients. In order to make TB patients get more benefit from BALF for diagnosis, we explore which indicator might be used to optimize the choice of bronchoscopy. METHODS: A total of 1539 sputum-smear-negative pulmonary TB suspects who underwent bronchoscopy were recruited for evaluation. The sensitivity, specificity and accuracy of Mtb detection in sputum and BALF were compared. Odds ratios and 95% confidence intervals were used to assess variables that associated with positive acid-fast bacilli (AFB) smear, Mtb culture and nucleic acid amplification test (NAAT) of BALF in sputum-negative and non-sputum-producing pulmonary TB suspects. RESULTS: BALF has significantly higher sensitivity (63.4%) than sputum (43.5%) for Mtb detection by culture and NAAT. 19.7% (122/620) sputum-negative and 40.0% (163/408) non-sputum-producing suspects had positive bacteriological results in BALF. Among sputum-negative and non-sputum-producing pulmonary TB suspects, the positivity of Mtb detection in BALF is associated with a younger age, the presence of pulmonary cavities and a positive result of interferon-gamma release assay (IGRA). Sputum-negative patients under 35 years old with positive IGRA and pulmonary cavity had 84.8% positivity of Mtb in BALF. CONCLUSIONS: Our study indicated that combination of age, the presence of pulmonary cavity, and the result of IGRA is useful to predict the positivity of Mtb detection in BALF among sputum-negative and non-sputum producing pulmonary TB suspects. Those who are under 35 years old, positive for the presence of pulmonary cavity and IGRA, should undergo bronchoscopy to collect BAFL for Mtb tests, as they have the highest possibility to get bacteriologically confirmation of TB.

[Study of infusion of oxygen-enriched liquid to correct severe hypoxemia in infectious diseases: a report of pilot clinical study].

OBJECTIVE: To investigate a new therapy for effectively correcting severe hypoxemia in patients with infectious diseases by infusion of oxygen-enriched liquid, in order to raise the partial pressure of blood oxygen without passing through pathologically damaged alveoli of such patients. METHODS: Intravenous drip with oxygen-enriched liquids was given to 6 cases suffering from severe acute respiratory syndrome (SARS), and 3 cases of acquired immune deficiency syndrome (AIDS) in the course of treatment for 1 to 5 days, 500-700 ml per day. RESULTS: For all the 9 SARS cases, their hypoxemia was gradually corrected to normal in 20 minutes' or 4 hours' intravenous drip with oxygen-enriched liquid. Respiratory rate decreased from 29-49 breath/min to 18-22 breath/min, heart rate decreased from 89-145 beats/min to 60-79 beats/min, two faint patients regained consciousness, hypoxemia was redressed, partial pressure of oxygen in artery increased from 56 mm Hg (1 mm Hg=0.133 kPa) to 87 mm Hg, saturation of oxygen increased from 0.89 to 0.96. CONCLUSION: Intravenous drip of the oxygen-enriched liquid effectively helped correct the hypoxemia of SARS and other infectious diseases cases by bypassing the diseased alveoli through which oxygen would not pass into the blood by conventional oxygen inhalation. This therapy of oxygen-enriched liquid infusion could be quite life-saving in the combined treatment for SARS and other infectious diseases.