Medical and surgical treatment of parapneumonic effusions: An evidence-based guideline

Objective: A panel was convened by the Health and Science Policy Committee of the American College of Chest Physicians to develop a clinical practice guideline on the medical and surgical treatment of parapneumonic effusions (PPE) using evidence-based methods. Options and outcomes considered: Based on consensus of clinical opinion, the expert panel developed an annotated table for evaluating the risk for poor outcome in patients with PPE. Estimates of the risk for poor outcome were based on the clinical judgment that, without adequate drainage of the pleural space, the patient with PPE would be likely to have any or all of the following: prolonged hospitalization, prolonged evidence of systemic toxicity, increased morbidly from any drainage procedure, increased risk for residual ventilatory impairment, increased risk for local spread of the inflammatory reaction, and increased mortality. Three variables, pleural space anatomy, pleural fluid bacteriology, and pleural fluid chemistry, were used in this annotated table to categorize patients into four separate risk levels for poor outcome: categories 1 (very low risk), 2 (low risk), 3 (moderate risk), and 4 (high risk). The panel’s consensus opinion supported drainage for patients with moderate (category 3) or high (category 4) risk for a poor outcome, but not for patients with very low (category 1) or low (category 2) risk for a poor outcome. The medical literature was reviewed to evaluate the effectiveness of medical and surgical management approaches for patients with PPE at moderate or high risk for poor outcome. The panel grouped PPE management approaches into six categories: no drainage performed, therapeutic thoracentesis, tube thoracostomy, fibrinolytics, video-assisted thoracoscopic surgery (VATS), and surgery (including thoracotomy with or without decortication and rib resection). The fibrinolytic approach required tube thoracostomy for administration of drug, and VATS included postprocedure tube thoracostomy. Surgery may have included concomitant lung resection and always included postoperative tube thoracostomy. All management approaches included appropriate treatment of the underlying pneumonia, including systemic antibiotics. Criteria for including articles in the panel review were adequate data provided for ≥ 20 adult patients with PPE to allow evaluation of at least one relevant outcome (death or need for a second intervention to manage the PPE); reasonable assurance provided that drainage was clinically appropriate (patients receiving drainage were either category 3 or category 4) and drainage procedure was adequately described; and original data were presented. The strength of panel recommendations on management of PPE was based on the following approach: level A, randomized, controlled trials with consistent results or individual randomized, controlled trial with narrow confidence interval (CI); level B, controlled cohort and case control series; level C, historically controlled series and case series; and level D, exert opinion without explicit critical appraisal or based on physiology, bench research, or ’first principles.’ Evidence: The literature review revealed 24 articles eligible for full review by the panel, 19 of which dealt with the primary management approach to PPE and 5 with a rescue approach after a previous approach had failed. Of the 19 involving the primary management approach to PPE, there were 3 randomized, controlled trials, 2 historically controlled series, and 14 case series. The number of patients included in the randomized controlled trials was small; methodologic weaknesses were found in the 19 articles describing the results of primary management approaches to PPE. The proportion and 95% CI of patients suffering each of the two relevant outcomes (death and need for a second intervention to manage the PPE) were calculated for the pooled data for each management approach from the 19 articles on the primary management approach. The pooled proportion of deaths was higher for the no drainage (6.6%), therapeutic thoracentesis (10.3%), and tube thoracostomy management approaches (8.8%) than for the fibrinolytic (4.3%), VATS (4.8%), and surgery (1.9%) approaches, but the 95% CI showed considerable overlap among all six possible primary management approaches. The pooled proportion of patients needing a second intervention to manage the PPE was also higher for the no drainage (49.2%), therapeutic thoracentesis (46.3%), and tube thoracostomy (40.3%) management approaches than the fibrinolytic (14.9%), VATS (0%), and surgery (10.7%) approaches; there was no overlap in the 95% CI between the first three and the last three management approaches, indicating a nonrandom difference. Recommendations: The studies identified through a careful literature review as relevant to the medical and surgical management of PPE have significant methodological limitations. Despite these limitations in the data, there did appear to be consistent and possibly clinically meaningful trends for the pooled data and the results of the randomized, controlled trials and the historically controlled series on the primary management approach to PPE. Based on these trends and consensus opinion, the panel recommends the following approach to managing PPE: In all patients with acute bacterial pneumonia, the presence of a PPE should be considered. Recommendation based on level C evidence. In patients with PPE, the estimated risk for poor outcome, using the panel recommended approach based on pleural space anatomy, pleural fluid bacteriology, and pleural fluid chemistry, should be the basis for determining whether the PPE should be drained. Recommendation based on level D evidence. Patients with category 1 or category 2 risk for poor outcome with PPE may not require drainage. Recommendation based on level D evidence. Drainage is recommended for management of category 3 or 4 PPE based on pooled data for mortality and the need for second interventions with the no drainage approach. Recommendation based on level C evidence. Based on the pooled data for mortality and the need for second interventions, therapeutic thoracentesis or tube thoracostomy alone appear to be insufficient treatment for managing most patients with category 3 or 4 PPE. Recommendation based on level C evidence. However, the panel recognizes that in the individual patient, therapeutic thoracentesis or tube thoracostomy, as planned interim steps before a subsequent drainage procedure, may result in complete resolution of the PPE. Careful evaluation of the patient for several hours is essential in these cases. If resolution occurs, no further intervention is necessary. Recommendation based on level D evidence. Fibrinolytics, VATS, and surgery are acceptable approaches for managing patients with category 3 and category 4 PPE based on cumulative data across all studies that indicate that these interventions are associated with the lowest mortality and need for second interventions. Recommendation based on level C evidence.