The in vitro efficacy of Varidase versus streptokinase or urokinase for liquefying thick purulent exudative material from loculated empyema

Patients with loculated parapneumonic effusion or empyema are sometimes tre ated with streptokinase or urokinase in an attempt to facilitate pleural fl uid drainage by liquefying the pleural exudate and destroying the fibrin me mbranes producing the loculation. This study evaluated the effectiveness of streptokinase, urokinase, and Varidase (the combination of streptokinase a nd streptodornase) in liquefying gummy, purulent, exudative material from l oculated empyemas. An empyema was created by injecting 10(8) Pasteurella mu ltocida bacteria into the pleural space of New Zealand white rabbits. Twent y specimens, each containing 0.5 g of purulent material obtained 5 days aft er empyema induction, were placed in test tubes. Streptokinase( 15,000 IU), urokinase(10,000 IU), Varidase (4,000-15,000 IU streptodornase + 15,000 IU streptokinase) or saline was added to five sets of four test tubes each. T he amount of nonliquefied material that remained after incubation with the fibrinolytic agents was quantitated. Over the 6-h incubation period, the am ount of nonliquefied material decreased from 0.5 g to 0.02 g in the Varidas e group but never decreased to less than 0.4 g in any of the other three tr eatment groups. Liquefaction of thick pleural exudates from rabbits with em pyema can be achieved with Varidase but not with streptokinase or urokinase .