In a recent issue of the Annals of Thoracic Surgery, Chung et al. attempt to answer the long-standing question over the optimal timing of surgical intervention for empyema. This has been a long-standing debate among surgeons and other medical specialists. Despite advances in thoracic surgery (such as video-assisted thoracoscopy) as well as wealth of surgical commentary suggesting earlier intervention, surgery is usually considered a last resort; often after weeks or months of antibiotics, tube thoracoscopy or fibrinolytic therapy.
Chung et. al raise the stakes for this discussion with their research into this issue. In “Optimal timing of thoracoscopic drainage and decortication for empyema,” over the course of 8 years, the authors compared outcomes such as chest tube duration, number of persistent air leaks and overall length of stay by the time interval of symptomology and surgical treatment.
Why this is important
As discussed in previous posts, empyema is a serious infection with a mortality rate of approximately 1 in 5 patients. Empyema is frequently found in the chronically ill, debilitated or malnourished. Delays in definitive treatment (surgical decortication) plays a role in the high rate of mortality with this condition; with increased hospital stays, and increased patient debility as the patient continues to sicken, and consume their health reserves while less effective treatments are initiated.
What is early? What is optimal?
Early surgical intervention has been theorized since the turn of the 20th century to lessen morbidity and mortality, however there have been very few actual studies to address the question of timing. This study, while small, directly compares outcomes in patients receiving VATS at different points in the infectious process/ illness spectrum.
Using a retrospective study design, patients from April 2004 to March 2012 were subdivided into three different time intervals; symptoms for less than 2 weeks, 2 to 4 weeks and patients with symptoms persisting longer than 4 weeks prior to surgery. Of the 128 empyema patients, the vast majority (93.7%) were treated with VATS, with only 8 patients undergoing open procedures like thoracotomy.
Patients included in the study met criteria set forth in 2000 by the American College of Chest Physicians for diagnoses of Empyema and Loculated pleural effusions with thickened parietal pleura. Patient symptomology including symptoms such as dyspnea, persistent fever and sepsis were also taken into account when determining eligibility for surgical management.
Patients by intervals:
Less than 2 weeks (group 1) : 73 patients
2 to 4 weeks (group 2) : 43 patients
More than 4 weeks (group 3) : 14 patients
The vast majority of patients were male, with only 14 female patients in this study – spread throughout the groups. Additional variables such as age and pre-existing and co-morbid conditions (diabetes, liver disease, TB or other lung disease, etc.) were also collected*. The percentage of patients in each group who had undergone additional treatments for empyema pre-operatively (thoracentesis, antibiotics, etc.) was similar in all groups for antibiotics (ranging from 93% in group 1 to 100% of group 3) with around a quarter of both group 1 (24.6%) and group 3 (28.6%) requiring immediate surgery due to deteriorating status.
The 8 thoracotomy patients were used as a comparison group to evaluate the effectiveness of VATS for chronic empyema. All eight open surgical had pre-operative empyemas of 4 weeks duration or more.
What was compared/ measured?
While patient pre-operative characteristics were collected and analyzed as part of the evaluation of the empyema groups, the main surgical outcome measures were:
– Duration of procedure: Shorter in group 1 (average 100 minutes) versus group 2 (125 minutes) and group 3 (138 minutes).
– Chest tube duration – shorter in groups 1 (6.92 days) and 2 (7.45 days) than group 3 (10 days).
– Length of overall post-operative hospitalization: shorter in group 1 (9.49 days) and 2 (9.73 days) compared to group 3 (13.5 days).
– Length of post-operative ICU stay: no significant difference
Other surgical outcomes
Overall post-operative mortality was zero. There was no incidence of post-operative respiratory failure.
Re-operations/ Additional procedures:
Group 1 (73 patients) 2 patients with treatment failure/ empyema reoccurrence requiring re-operation with VATS (2.7%).
1 patient without complete resolution with VATS, required conversion to open decortication.
1 patient that developed a contralateral pleural effusion that required chest tube placement.
Total re-operations: 3 (4.0%)
Group 2: No re-operations.
Group 3 (14 patients)
1 patient required re-operation with VATS for treatment failure.
Prolonged air leak
Group 1: 2 patients (2.7%)
Group 2: 1 patient (3%)
Group 3: 4 patients (28.6%)
The biggest weaknesses in this study are the small number of participants in group 3, and the lack of a control group.
Small numbers = reduced strength of findings
How much more powerful would similar results be, had the numbers of participants in all the groups been equivalent? For example, if Chung et al. presented data showing that air leaks occurred in over 28% of patients with older empyemas (group 3) in comparison with groups 1 (2.7% and group 2: (3%) if these groups had been equally populated, would be a much stronger argument for earlier intervention.
As it is, with just 14 participants in group 3, 28.6% is less of a dramatic finding than false precision from small numbers. However, it serves as a credit to Dr. Chung and his medicine colleagues, as clinicians, that the majority of these patients received definitive treatment at earlier stages.
Lack of control group
Had researchers included patients who were treated only by non-surgical methods (up to 2 weeks duration) and compared the overall length of stay, incidence of respiratory failure, ICU days and mortality in these patients, the data would have had an increased impact. However, questions remain regarding the use of VATS versus the current standards of treatment in this ‘early’ group. While we can partially speculate that treatment failures of patients in this group represent later patients (i.e. Patient fails treatment and is referred for surgery and becomes part of group 1, 2 or 3), the missing information may have represented a crucial factor to drive the decision-making process.
For example, how many patients in that same time period, presented with early empyemas and:
– Received antibiotics and recovered?
– Were admitted to the hospital and died of respiratory failure/ sepsis etc. without ever making it to surgery?
But, presumably, the difficulties of collecting this data retrospectively were prohibitive. However, does the high rate of immediate surgery in group 1 due to patient deterioration serve as a partial stand-in for this data?
While further study is warranted to determine the optimal time for surgical intervention in empyema thoracis, this study does an adequate job at demonstrating the benefits of earlier surgical intervention. While there was no mortality in any of the groups, patients who were operated on 4 weeks or more after being diagnosed/ demonstrating symptoms of empyema, required longer operations, developed more persistent air leaks post-operatively, with longer chest tube duration and longer overall hospital stays.
Further research in this area could include the use of experimental algorithms and protocols to ‘fast-track’ patients with loculated effusions/ empyemas to surgical decortication in an attempt to replicate or further demonstrate improved patient outcomes with earlier surgical intervention. These algorithms would explore the use of surgery as a first-line treatment with adjuvant antibiotics independent of thoracentesis, tube thoracostomy.
*Full information is provided within several tables in the original article.
Chung, Jae Ho et al. (2013). Optimal timing of thoracoscopic drainage and decortication for empyema. Annals of Thoracic Surgery, 2013.