IMAGE-GUIDED MANAGEMENT OF COMPLICATED PLEURAL FLUID COLLECTIONS

Abstract

Percutaneous image-guided catheter drainage with adjunctive ICFT has become the mainstay in the treatment of complicated pleural fluid collections. There are six basic principles of image-guided drainage and ICFT that must be understood to maximize the efficacy and safety of the procedure. 1. There must be a basic understanding of why traditional nonguided thoracostomy drainage fails in a significant percentage of patients. Tube malposition relative to fluid loculations, fluid debris and viscosity, and the presence of a stage 3 pleural peel are the primary reasons for failure. Image-guided placement of drains addresses the issue of tube malposition and ICFT greatly facilitates drainage of fibrinous fluid. 2. Proper use of cross-sectional imaging is one of the keys to ultimate success. CT and ultrasound allow very accurate assessment of the underlying pathologic process and are crucial in planning the drainage procedure, guiding the actual placement of drains, and following the course and outcome of treatment. The added costs of cross-sectional imaging are more than compensated by the increase in success of the drainage procedure. 3. Aggressive catheter management is the single most important factor in success. Multiple loculations require multiple catheters for adequate drainage. Pleural adhesions may form quickly as drainage progresses leading to the formation of undrained loculations. Frequent cross-sectional imaging is needed to detect undrained loculations so that additional drainage catheters may be placed if needed. It is crucial that the drainage catheter always be properly positioned in relation to fluid loculations. 4. Intracavitary fibrinolytic therapy is a very powerful adjunctive therapy to aid in complete evacuation of fluid collections that contain fibrin nets and debris. It can also partially débride the pleural surfaces of fibrinous debris and facilitate complete re-expansion of the underlying lung. Intracavitary fibrinolytic therapy should not be used in an attempt to salvage success by a malpositioned chest tube. 5. The ultimate success of closed drainage for complicated pleural fluid collections is closely related to the age of the effusion at the time of drainage. A very high rate of clinical success may be expected when these techniques are used in the treatment of stage 2 fibrinopurulent effusions. If drainage is delayed until the third stage (fibrous pleural peel formation) then closed drainage likely will fail and a formal thoracotomy and decortication will be necessary. Experience in the literature suggests that effusions up to 4 to 6 weeks in duration may be drained successfully but those older than 6 weeks likely will have an associated pleural peel. Effective pleural drainage must be instituted early in the course of the disease process. 6. There may be significant residual pleural and parenchymal inflammatory changes after complete drainage of a stage 2 effusion. If the fluid in the pleural space has been adequately drained and the visceral and parietal pleural surfaces apposed, then the residual inflammatory pleural thickening and associated lung consolidation resolve over 2 to 4 months and pulmonary function returns to baseline. Imaging studies immediately after complete pleural drainage are not normal. These residual abnormalities should not be interpreted as evidence that open surgical drainage should have been performed. Effective closed drainage carries lower morbidity, mortality, and cost than does open surgical drainage. For radiologists and clinicians alike it does not suffice simply to place one or more thoracostomy tubes, round daily, and hope that the occasional use of fibrinolytic agents does the rest. Without a more aggressive approach to catheter position and management the efficacy is no greater than that historically seen with nonguided closed drainage and surgeons will continue to plead for earlier effective open drainage.