Controlled Trial of Intrapleural Streptokinase in the Treatment of Pleural Empyema and Complicated Parapneumonic Effusions (Materials and Methods)

30 Dec

Controlled Trial of Intrapleural Streptokinase in the Treatment of Pleural Empyema and Complicated Parapneumonic Effusions (Materials and Methods)This was a 5-year (1990 to 1995), prospective study of 52 consecutive patients admitted to the hospital with community-acquired empyema and complicated (high-risk) parapneumonic effusions. Empyema (40 patients) was defined according to one or more of the following criteria; grossly purulent fluid; positive fluid culture; and positive Gram stain for bacteria. Complicated parapneumonic effusions (12 patients) were defined according to Light viz pH <7.00 or lactate dehydrogenase (LDH) level >1,000 U/L. Patients with tuberculous, hospital-acquired, posttraumatic, and postoperative empyemas were excluded. Diagnostic thoracentesis with a 14-gauge venula was performed for all patients on hospital admission. The pleural fluid samples were sent for biochemical analysis (sugar, protein, pH, LDH); for differential cell counts; Gram stain; and aerobic, anaerobic, and mycobacterial cultures. Closed tube thoracentesis with a size 24 chest tube was performed at the bedside in patients with large, dependent pleural collections.

In patients with effusions that were multiloculated and/or were in nondependent areas, 7 to 12F pigtail catheters were placed under ultrasound guidance. All patients were seen at least daily to assess progress. The need for further imaging and drainage was decided on an individual basis. CT examinations were made in all patients with suspected multiloculation and who failed to respond promptly.

The two treatment protocols, Drain and tube drainage with adjunctive intrapleural SK, were instituted in a sequential manner with Drain utilized for the first 2.5 years and SK used exclusively in the last 2.5 years of the study. The same team of chest physicians was responsible for patient care over the whole study period with a consistent approach to the initial choice of empiric antibiotics, the indications for further intervention (including open or thoracoscopic surgical drainage and decortication), and eventual discharge from hospital.

In the SK protocol, we administered 250,000 U of SK in 100 mL of saline solution into the pleural cavity on a daily basis. Each dose of SK was left in the pleura for 4 h with the chest tube clamped following which the fluid was manually aspirated and then released into an underwater seal for passive drainage. The total number of doses was determined by patient response. Contraindications to the use of SK was known allergy or a history of bleeding ulcer disease.

The chest drains were removed when the daily drainage had fallen below 50 mL with clinical and radiologic resolution of the pleural collection. Either thoracoscopic or open surgical drainage and decortication was performed only if there had been no response to either treatment protocols and the empyema had organized itself into a pleural peel visible on the CT.

We prospectively evaluated the effect of the two different treatment protocols on the following clinical outcomes: volume of pleural fluid drained on a daily and cumulative basis; duration from the day of hospital admission to defervescence; duration of hospital stay; need for surgical intervention; and mortality.

All results were expressed as mean (SD) values. Continuous variables were compared with paired and unpaired Student’s t tests where appropriate while the x2 was used to test for differences between proportions.