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Charleston, SC
Dr. Heffner is Professor of Medicine and Executive Medical Director, Medical University of South Carolina. Dr. Huggins is a Senior Clincal Fellow in the Pulmonary/Critical Care Division at the Medical University of South Carolina.
Correspondence to: John E. Heffner, MD, FCCP, Professor of Medicine, Executive Medical Director, Medical University of South Carolina, 169 Ashley Ave, PO Box 250332, Charleston, SC
The occurrence of a spontaneous pneumothorax represents a troubling milestone in the course of patients with moderate-to-severe COPD. A pneumothorax causes rapidly progressive and alarming degrees of dyspnea usually associated with pleuritic chest pain. Hospitalization is necessary and often prolonged, and most patients require an intercostal chest tube and consideration of a surgical procedure to induce pleurodesis. But beyond these distressing experiences, a spontaneous pneumothorax represents a significant marker of mortality for patients with COPD. Each pneumothorax occurrence increases the chances of dying by nearly fourfold.1 In light of this lethal potential, the recurrence rate of secondary spontaneous pneumothoraces is especially alarming. Up to 40 to 50% of patients will have a second pneumothorax if pleurodesis is not performed.123
These observations prompt experts in pleural disease to recommend a more aggressive approach to managing secondary spontaneous pneumothorax as compared with primary spontaneous pneumothorax, which are usually well tolerated because of the absence of underlying lung disease. Despite recommendations for aggressive care, little consensus exists regarding the specifics of the management approaches that should be applied. For example, the American College of Chest Physicians (ACCP) consensus statement on pneumothorax recommends chest tubes for all patients and pleurodesis with the first episode of a secondary spontaneous pneumothorax to prevent a recurrence.4 The consensus was incomplete, however, in that 19% of the expert panel would defer pleurodesis until the second pneumothorax. The British Thoracic Society (BTS) pneumothorax guidelines recommend manual aspiration with a catheter and syringe for small pneumothoraces in patients with mild underlying lung disease, but submit that most patients will require chest tube drainage.5 The BTS recommends removal of the chest tube after lung re-expansion and resolution of air leaks, and reserves pleurodesis for patients with an unresolved air leak or a recurrent pneumothorax.
Even less consensus exists regarding the ideal method for pleurodesis once it becomes indicated. The ACCP recommends medical thoracoscopy or video-assisted thoracoscopic surgery (VATS) as the primary procedure, and a limited axillary thoracotomy with pleural abrasion as a secondary approach.4 These guidelines value the lower morbidity attached to minimally invasive procedures. The BTS recommends open thoracotomy with repair with VATS reserved for patients who cannot tolerate an open procedure.5 This approach values the high effectiveness and low mortality of the open procedure and cites the limited availability of randomized controlled trials that compare VATS with thoracotomy.
Considering the clinical confusion that emerges from these varying recommendations, any new data entering the arena of pneumothorax management are greatly appreciated. The study by Lee and colleagues (see page 1316) provides novel information by reporting their experience with medical thoracoscopy and talc poudrage for pleurodesis in 41 patients with moderate COPD (73% of patients, FEV1 
30% but > 50% predicted) or severe COPD (27% of patients, FEV1 < 30% predicted) who presented with either an initial (66% of patients) or recurrent (34% of patients) pneumothorax. Of note, the investigators did not perform any procedures to eliminate blebs or bullae. They conclude that medical thoracoscopy was well tolerated with no major perioperative complications and a 30-day mortality of 10%, with the four deaths in the study confined to patients with severe COPD and ischemic heart disease. All patients who survived the hospitalization were discharged with resolution of their pneumothoraces after a median 5-day length of stay. Only 5% of patients had a pneumothorax recurrence during 19 to 47 months of follow-up. Further characterizing secondary pneumothorax as an ominous portent, 17% of patients died within 1 year of discharge from complications related to their underlying cardiopulmonary disease.
Lee and colleagues advanced our understanding of secondary pneumothorax by limiting their investigation to patients with COPD. Other investigators6789 have demonstrated the efficacy of thoracoscopic poudrage in general categories of patients with primary and secondary pneumothorax. But these studies did not present data stratified by underlying lung disease. Despite its strengths, however, the present investigation remains a single-arm, observational study and, consequently, requires considerable speculation and a healthy dose of skepticism to appraise its findings.
For instance, the authors note that only 44% of patients had blebs and bullae by thoracoscopic inspection of the visceral pleural, which is lower than expected for a cohort of patients with spontaneous pneumothorax due to COPD.10 As mentioned in the discussion, the investigators may have underestimated the presence of these lesions because of limitations of thoracoscopy for inspecting apical regions of the lung where most blebs and bullae occur.11 As suggested by the authors, this underestimate may create the impression that blebs and bullae do not require excision during medical thoracoscopic poudrage.
Such an approach, however, differs from existing recommendations to convert patients to VATS or thoracotomy to manage bullae > 2 cm noted during medical thoracoscopy.121314 Although removal of blebs offers little benefit for patients with primary spontaneous pneumothorax managed by thoracoscopy,13 the presence of large bullae decreases the success of thoracoscopy in managing secondary pneumothoraces.78 In support of their approach, the authors cite the experience of Liu and coworkers,15 who reported good results with thoracoscopic poudrage without bleb- or bullectomy in 13 patients with COPD. Of note, however, most of the patients reported by Liu and coworkers underwent Endoloop (Ethicon; Somerville, NJ) resections of blebs and bullae except for these 13 patients who had "diffuse emphysema" and, presumably, no resectable localized lesions.15 We remain reluctant, therefore, to conclude that blebs and bullae do not require resection, coagulation, stapling, or oversuturing, considering the relatively small size of the present study. Moreover, 59% of the patients reported by Lee and coworkers had preexisting tuberculosis, which is an independent cause of secondary pneumothorax and a confounder of their results. Nevertheless, this discussion further highlights the lack of high-quality evidence to direct therapy for blebs and bullae at thoracoscopy.
One must also scrutinize the results of the study relative to its rationale. In their introduction, the authors state that they commonly encounter patients with COPD for whom general anesthesia and surgery present considerable risks. Medical thoracoscopy, in their view, offers such patients a well-tolerated option for pleurodesis. Yet, the four deaths in the study occurred in patients with more advanced COPD and ischemic cardiac disease. These results prompted Lee and colleagues to recommend such patients for talc slurry pleurodesis via chest tube rather than thoracoscopy, thereby weakening the study rationale. One might alternatively conclude, however, that patients with advanced COPD require the attention of an anesthesiologist skilled in preoperative assessment and intraoperative management of high-risk patients. It has previously been observed that medical thoracoscopists need to enhance their skills in treating pain,13 which can precipitate catecholamine release and perioperative myocardial ischemia.16 Moreover, Mukaida and coworkers17 demonstrated in a small series that high-risk patients can tolerate VATS when carefully managed with local and epidural anesthesia. Once again, additional therapeutic confusion exists regarding patient selection for medical thoracoscopy relative to other available pleurodesis techniques.
Finally, we note that no procedure was performed or planned during medical thoracoscopy other than talc poudrage. Other reports of medical thoracoscopy for pleurodesis emphasize the twin value of thoracoscopy in both administering talc and staging the pleural space.8 If thoracoscopy is only needed to administer talc, one could question if results would have been similar for the studied patient population had they been treated with talc slurry via a chest tube without thoracoscopy.
Perhaps the most important outcome of the study by Lee and colleagues is the focus it brings to the paucity of randomized controlled trials that address management of secondary spontaneous pneumothorax for the population at greatest risk—patients with COPD. One cannot avoid catching the scent of confusion in the air when attempting to interpret the numerous noncomparative studies that examine the value of markedly different pleurodesis modalities studied in aggregate populations with diverse underlying respiratory conditions. Considering the importance of spontaneous pneumothorax for patients with COPD, multicenter trials akin to those recently completed for lung volume reduction surgery are needed. Anticipating that such trials will be many years from conception to completion—if they occur at all—we need formal decision analyses to weigh the relative value of different management approaches18 as have been performed for primary spontaneous pneumothorax.19 Such analyses are especially important considering the opinion of some pleural experts that the risk of talc-induced acute lung injury does not justify its use.20
Meanwhile, we are left with our previously stated and less-than-satisfying recommendation to individualize care based on the available techniques at local institutions that match best-reported clinical outcomes.21 Albeit necessary with our present state of knowledge, such recommendations further entrench practice variation, delay implementation of best clinical practices, and perpetuate our clinical confusion.
References
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