OBJECTIVE AND BACKGROUND - The aim of this study was to investigate the effectiveness of intrapleural heparin or heparin combined with human recombinant DNase in the treatment of empyema.
METHODS - Empyema was induced in rabbits with an intrapleural injection of 10(9)Pasteurella multicoda organisms in infusion agar via a surgically placed chest tube. Once empyema was verified, a blinded investigator administered drugs via the chest tube. There were three treatment groups each with six rabbits. One group was given 1000 IU heparin, a second group was given 1000 IU heparin plus 1 mg of human recombinant DNase via chest tube and the control group received saline. The rabbits received treatment every 12 h for a total of six treatments and the volume of each treatment was 3 mL. The animals were sacrificed at day 10 and the amount of empyema and pleural thickening was scored macroscopically on a scale of 0-6.
RESULTS - The total volume of pleural effusion aspirated was significantly higher in the heparin group (25.8+/-10.7 mL) compared with either saline (8+/-8.9) or heparin plus human recombinant DNase (6.8+/-6.1) groups (P=0.003). The mean empyema and pleural thickening scores did not differ significantly between the groups (P=0.8, P=0.5 respectively). A weak correlation was found between total volume of aspirated pleural fluid and pleural parameters of white blood cell counts and LDH levels (r=0.546 and P=0.02, r=0.631 and P=0.02 respectively).
CONCLUSION - The intrapleural administration of 1000 IU heparin alone or in combination with 1 mg of human recombinant DNase is no more effective than saline in the treatment of empyema in rabbits. Intrapleural heparin significantly increased the drainage of pleural fluid compared with the combination and saline group.