2.0 BACKGROUND INFORMATION AND RATIONALE
The European Association of Cardiothoracic Surgeons expert consensus statement for the surgical management of empyema groups empyema into three entities. They are Parapneumonic (stage I), Fibrinopurulent (Stage II) and Chronic Organizing (Stage III). Fibrinopurulent is further characterized by bacterial invasion across the damaged lung epithelium with pH\<7.2, glucose \<2.2mmol/L and LDH \>1000IU/L. These criteria along with a positive culture, gram stain or observed pus, is defined as an empyema.
Despite the high incidence of empyemas, there continues to be controversy regarding first line management. Conventional thoracostomy has evolved to include the addition of intrapleural fibrinolytics for those in the fibrinopurulent phase. Many different agents and combinations of fibrinolytics have been described in the literature, as well as optimal techniques for chest tube insertion. With respect to fibrinolytics, the most recent MIST 2 randomized control trial (RCT) examined four separate treatment arms; double placebo, placebo combined with intrapleural DNAse (5mg), intrapleural t-PA (10mg) with placebo, and intrapleural t-PA (10mg) combined with DNase (5mg) for six doses over three days. This study demonstrated a statistically significant difference in the reduction of pleural empyema in the t-PA and DNase combined arm (P=0.005) when compared with all the other arms. This RCT has established intrapleural fibrinolytic therapy as the gold standard treatment for those with empyema. When considering thoracostomy itself, the literature overwhelmingly suggests that image-guided thoracostomy decreases the rate of complications (pneumothorax, infection, procedure failure, intercostal bleeding), compared with a blind chest tube insertion.
A Cochrane Systematic Review of eight trials (6 children and 2 adults) examining treatment methods for empyema provided moderate quality evidence suggesting there were similar complication rates between VATS decortication and chest tube drainage. The review also demonstrated VATS decortication potentially decreases hospitalization length of stay. A recent study examined 4,095 patients using the New York State database to investigate patients undergoing treatment for empyema with chest tube insertion, VATS decortication, or open thoracotomy. Patients had a higher mortality during their initial hospital stay when they received a chest tube compared with those who underwent a surgical approach (chest tube:15.4%, VATS:4.7%, open: 6.0%, p\<0.001. Additionally, patients' readmission rate within thirty days was significantly higher for the chest tube group (6.1%) compared with the surgical group (VATS 1.9% and open: 2.1%, p\<0.001) lending support that an initial surgical approach for empyema may be warranted.
Two separate adult RCTs have attempted to compare VATS decortication to thoracostomy with fibrinolytics. Wait et al. in 1997 used a small study population of twenty patients in each arm, randomizing participants to either bedside thoracostomy with streptokinase or VATS decortication. This study demonstrated that in adults with a fibrinopurulent effusion, VATS decortication is associated with an increased rate of empyema resolution and a shorter length of stay. A review article published by Chambers et al examined twenty-eight studies, comparing decortication via thoracotomy to VATS decortication for empyema. The majority of studies demonstrated that VATS has a decreased length of hospital stay, decreased postoperative morbidity and decreased post-operative pain. Furthermore, there was a higher resolution of empyema during the fibrinopurulent phase. Despite these two studies demonstrating superior outcomes with VATs decortication, they still do not compare modern day standards of treatment for empyema.
As the above literature suggests, there have been multiple proposed methods for first-line treatment of an empyema. However, there have not been any studies that compare modern standards of practice. Image-guided chest tube insertion has been shown to be superior to bedside chest tube insertion. Fibrinolytics administered as per MIST2 protocol has become the standard of practice at many institutions. Furthermore, VATS decortication has shown promising outcomes as first-line treatment and is associated with decreased morbidity compared with an open thoracotomy approach. Therefore, it is being proposed to compare image-guided chest tube insertion with MIST 2 trial fibrinolytics (six treatments of DNAse 5mg and t-PA 10mg over three days) to VATS decortication for the primary treatment of adults presenting with empyema in the fibrinopurulent phase. The investigators will determine the rate of re-intervention required within thirty days of treatment.
3.0 RESEARCH STUDY DESIGN/ METHODOLOGY This is a randomized control trial occurring at the Kingston Health Sciences Centre (KHSC). Empyema is a disease that is best managed with the expertise at an institution with thoracic surgeons. The standard practice is that once the diagnosis is made at another hospital in our LHIN, these patients are transferred to our Thoracic Surgery centre.
Patients will receive a baseline CT Chest to confirm the presence of an empyema. Participants will have a diagnostic pleural thoracentesis performed by their primary care team initially to determine whether the pleural fluid is an exudate suggestive of an empyema in its fibrinopurulent phase (see inclusion criteria). Once this is performed and the diagnosis of an empyema is obtained, patients in our LHIN not at KHSC will be transferred as usual to KHSC to be managed by the thoracic surgery team. For patients under the care of a different service at KHSC, they will be transferred to be under the care of the thoracic surgery team.
Once admitted under the thoracic surgery service, the study team will be notified and information will be provided to the patients. Informed consent will be obtained at this time by a member of the study team. Using an online randomization tool, participants will be randomized into either the image-guided thoracostomy combined with MIST 2 Trial fibrinolytics arm or the VATS decortication arm. Both procedures will be carried out within forty-eight hours of participant arrival. Both arms will also receive concurrent IV broad-spectrum antibiotics. The image-guided thoracostomy arm will go to the interventional radiology suite where a 12-24Fr chest tube will be inserted at the discretion of the interventional radiologist based on the specific clinical picture. Data will be collected during their stay. The primary outcome of the study will be to determine the rate of reintervention required, including additional chest tube insertion or surgery. Secondary outcomes will include mortality, duration of hospital stay, and adverse events. Data will be collected 30 days after their initial intervention to determine if any re-intervention was necessary.
A repeat CT Chest will be performed prior to discharge, clinical consideration of chest tube removal, or if there is no clinical improvement.
