Managing Prolonged air Leak
Thoracic Surgery or Thoracoscopy and Talc Poudrage
Surgical treatment for PAL is typically undertaken by video-assisted thoracoscopic surgery (VATS), which has replaced open thoracotomy as the approach of choice. The aims of surgery are to identify and seal any areas of air leakage, and to resect any visible blebs or bullae on the visceral pleura, and then perform a pleurodesis procedure. Studies suggest that pleurodesis is required alongside bleb/bullectomy to achieve lower recurrence rates.[61–63] This can be achieved by pleural abrasion, pleurectomy, or chemical pleurodesis. A study of VATS for PSP recurrence prevention (or ongoing air leak) showed a lower rate of recurrence with talc poudrage compared with subtotal pleurectomy when used alone or alongside ligation or stapling of bullae (1.8% vs. 9.2%). This was confirmed further in two large case series of VATS with talc poudrage with a reported recurrence rates of 1.7 and 1.9%. Alternatively, patients with PAL or failed NA can be sent for medical thoracoscopy and talc poudrage with a recurrence rate of 5% compared to 34% for chest tube drainage in a prospective randomized study.
Recurrence Prevention After First Occurrence?
At present, recurrence prevention surgery or thoracoscopy and talc poudrage is only recommended after a subsequent recurrence (either ipsilateral or contralateral). This is controversial, and there are advocates of surgical intervention after a first episode of PSP. A case series of 185 patients in a single center, suggested a recurrence rate of 2.2%, but a high procedure-related morbidity rate of 7.6% and a mortality of 1.6%. There have now been two RCTs of early VATS compared to conservative management after first PSP: the first by Al-Mourgi and Alshehri was a small trial of 41 patients, in which the VATS group underwent surgery within 24 hours of admission to hospital compared to "conservative" treatment with chest tube drainage. They found no recurrence (0%) in the VATS group, compared to 40.9% in the conservative group, which is higher than previously reported.[29,30] The second larger RCT by Olesen et al enrolled 373 PSP patients again showed a significant lower recurrence rate in those treated with VATS (13%) compared to conservative treatment (34%). The 13% recurrence in the VATS group is unexpectedly high, but may represent the fact that they performed mechanical pleurodesis with abrasion rather than talc pleurodesis, which has a lower recurrence rate (as described in the previous paragraph).
Time to Change Guidelines?. Although these data are interesting, only around 28 to 30% of patients will recur with conservative (chest drainage) management.[29,30] Therefore, by operating on all patients at first occurrence, up to 72% of patients will have undergone an unnecessary procedure. Although VATS or medical thoracoscopy is generally considered a "safe" procedure, there is still risk of significant morbidity or mortality, especially prolonged discomfort of the chest after 3-port VATS. Besides, a VATS procedure includes routine resection of ELCs, which has not proved to be essential for recurrence prevention, and may be a redundant and costly procedure. In a recent task force statement, surgeons and pulmonologists could not agree upon the place of resection of ELCs in the surgical treatment of PSP. A more personalized approach in which those patients at higher risk could be identified, could shift the risk:benefit balance in favor of early surgery or thoracoscopy. Olesen et al attempted to do this by conducting a high-resolution CT (HRCT) scan in all patients. Unfortunately, stratification by bullae size or "dystrophic score" did not convincingly identify higher risk of recurrence in all patients. As such, the case for early surgery or thoracoscopy for PSP recurrence prevention has yet to be made. On the other hand, shared decision-making should become more important with the well-informed patient, who may want to avoid a 1 in 3 recurrence rate and therefore will have the possibility to choose treatment including recurrence prevention even after the first episode of PSP.
Patients Unfit for Surgery
Patients with SSP due to long-standing lung disease such as COPD and interstitial fibrosis are particularly susceptible to PAL. Unfortunately, the severity of their respiratory disease often means that they are unfit for surgical intervention due to high anesthetic risk. These patients are a significant management challenge and may undergo multiple and prolonged periods of drainage due to the presence of bronchopleural fistulas.
There are limited treatment options available for managing such cases. Attachment of a Heimlich valve to a patent chest drain may facilitate discharge from hospital and outpatient follow-up in the more stable patients. Another option is to perform a pleurodesis procedure via the chest drain: this could be "medical" pleurodesis or the instillation of autologous blood ("blood patch pleurodesis").
Pleurodesis is applying chemical or mechanical injury to the pleura in order to induce inflammation and subsequent adherence to prevent recurrence. "Medical" pleurodesis is accomplished by applying a chemical irritant to the pleural space. This may be appropriate for difficult or recurrent pneumothoraces (PSP and SSP) especially for patients who are not fit for surgical intervention. Graded talc, tetracycline, minocycline, and autologous blood have been all studied as pleurodesis agents for recurrence prevention in SP.
Graded talc is the most popular and successful agent for pleurodesis.[1–3] Talc is effectively used to treat malignant pleural effusion and the success rates of pleurodesis using it are high (> 90%). It can be sprayed in the pleural cavity as poudrage during medical thoracoscopy with the understandable advantage of visually ensured uniform distribution all over the thoracic cavity. The other simpler way is to dissolve it in saline and apply it as slurry via chest drain.
A recent systematic review compared the efficacy of chemical pleurodesis in SP using different sclerosing agents via either medical or surgical approaches. In the medical approach, talc poudrage during medical thoracoscopy had the lowest recurrence rate which was reported to be between 2.5 and 10%. The recurrence rates with tetracycline instillation through chest tubes were estimated to be between 13 and 33%. The recurrence rate using talc slurry has been reported to be 34%.
An RCT by Chen et al attempted pleurodesis for patients presenting with the first PSP. The group found that additional minocycline pleurodesis after simple aspiration and drainage of the first PSP reduced the rate of recurrence at 1 year from 49.1% in the control group to 29.2% in the treatment group. This study has been criticized because of the considerably higher recurrence rate observed in the control arm than seen in previous reports. Also, minocycline is not available in many areas of the world, and its use in pleurodesis can be associated with significant pain.
Blood Patch Pleurodesis
This "blood patch pleurodesis," in which 1 to 2 mL/kg of the patient's venous blood is inserted in to the chest drain, can successfully end air leak. The term "pleurodesis" here is a misnomer as it is presumed that fibrin and clotting factors within the blood act to repair the visceral air leak and resolve the pneumothorax. Another possible treatment option is the use of endobronchial valves (used in COPD treatment to achieve lung volume reduction) inserted at bronchoscopy to occlude the relevant lung segment and hence close the bronchopleural fistula.
Patients treated for pneumothorax should be followed up by a respiratory specialist after being discharged. Whether these patients have been treated conservatively or by any technique for drainage, they need to be instructed to return to the emergency department should breathlessness develop again. During follow-up, the presence of any underlying lung disease should be explored and management started if any is identified. The patient needs to be aware of the risk of recurrence and the discussion should include the possibility of future surgical intervention if this occurs.
Lifestyle advice on smoking (cigarettes as well as marijuana), air travel, and diving should also be reinforced. No evidence suggests that the differences in atmospheric pressure occurring during commercial air travel by itself precipitates pneumothorax, but undrained pneumothorax with persisting air leak will increase in size and thus it is an absolute contraindication for air travel. Current guidance recommends waiting for 7 days after radiological resolution of pneumothorax before flying. Patients who had definitive surgical/thoracoscopic management for pneumothorax can fly once they have fully recovered from surgery, but should be aware that recurrence still remains at 1 to 2%. In cases of SSP without the possibility for surgery, patients should be advised to seek other safer modes of transportation.
Diving (using compressed gas) should be permanently avoided unless a definitive prevention strategy such as a surgical pleurectomy has been performed.
There is no evidence to link recurrence with physical exertion, so the patient can be advised to return to work and to resume normal physical activities once their symptoms have resolved.
Areas of Future Research
At present, patients with pneumothorax are managed simply according to presumed presence of lung disease or not: that is, PSP or SSP. However, there is a need to personalize the approach. Generic management leads to uncertainty about immediate success rates and risk of recurrence. A number of previous studies have attempted to stratify patients based upon the appearance of the lung on CT scans, but the results of classifying by bleb count and size ("dystrophic score") are variable. Further work is needed to find clinical–radiological predictors of outcome.
Measurement of air leak (air flow through the chest drain) using digital suction device early in the treatment course has the potential to predict failure of medical management. Further work is required to validate the exact threshold of air leak to robustly predict failure, which may allow early triage to thoracic surgery and thereby remove the need for prolonged in-patient stay.
There is a trend to outpatient treatment of patients with uncomplicated PSP, and results of ongoing trials should clarify the efficacy and safety of this approach. There is need for surgical research to make clear if the current practice of resection of ELCs is routinely necessary, and not a redundant procedure besides pleurodesis.
Semin Respir Crit Care Med. 2019;40(3):314-322. © 2019 Thieme Medical Publishers