Computerized tomography in the assessment of a posterior mediastinal tumor.

CHEST, 79: 6, JUNE, 1981 COMMUNICATIONS TO THE EDITOR 715 culture results we have observed marked loculation in spite of antibiotic therapy which required open drainage. Therefore, we feel that early indicators of potential complications such as a low pleural fluid pH are extremely helpful in guiding therapy. In the patient with a nonloculated, nonpurulent gramstain negative fluid and a pH in the 7.30 range, we recommend another thoracocentesis be performed in six to eight hours while the patient is receiving appropriate antibiotic coverage for the pneumonia. If the pH is stable and the pleural space is not loculated, we would not institute surgical drainage. However, if the pH has dropped substantially we choose to drain the pleural space. The pleural fluid glucose (less than 60 mg per deciiter)2 and the LDH (greater than 1,000 lU/L ) 3 are also helpful in this regard, but probably are not as sensitive as the pleural fluid pH. It is important to stress that any laboratory tests must be interpreted in light of the clinical setting. This is particularly true of the patient with a parapneumonic effusion. The patient who has become afebrile with antibiotics and has nonloculated, bacteriologically negative fluid and a pH of 7.25 will likely do well with antibiotics alone. On the other hand, the patient who continues to remain febrile and shows a fall in pH on serial thoracocentesis should have chest tube drainage performed. It has been our experience that the morbidity and economic burden from chest tube insertion and drainage is far less than from a thoracotomy and additional hospitalization. Thus, we tend to institute chest tube drainage early, as once loculation occurs, the need for a thoracotomy for resolution of the empyema increases markedly. James T. Good, Jr., M.D., F.C.C.P. and Stephen A. Sahn, M.D., F.C.C.P., Department of Health and Hospitals, City and County of Denver