Pierre Theodore
Presentation
A 65-year-old man with a history of chronic obstructive pulmonary disease (COPD), hypertension, and a 50 pack-year history of smoking presents with acute-onset shortness of breath. He regularly has dyspnea on exertion but suddenly became short of breath at rest 1 hour ago. He has new right-sided chest pain, which he describes as knife-like and worse on inspiration. He has no history of pneumothorax, acute coronary syndrome, or stroke. He denies recent chest trauma. He smokes one pack of cigarettes per day. On physical examination, he is tachycardic, hypertensive, and tachypneic, and his oxygen saturation is 85% on room air. He has decreased breath sounds on the right side, decreased chest expansion on the right, and hyperresonance to percussion on the right. His trachea is midline.
Differential Diagnosis
Spontaneous pneumothorax in a young person is usually a rupture of a subpleural bleb in the lung apex without underlying lung disease and is known as primary spontaneous pneumothorax. Classically, patients are tall, young men who are light to moderate smokers and often physically active.
In the case patient, the pneumothorax is likely secondary to underlying lung disease. Other causes of secondary spontaneous pneumothorax include airway diseases, such as cystic fibrosis or asthma; significant lung infections, such as Pneumocystis jiroveci (P. carinii) pneumonia or tuberculosis; and other intrapulmonary diseases such as lung tumors, inflammatory lung disease, and connective tissue diseases of the lung. Pneumothoraces may also be due to trauma or iatrogenic causes such as subclavian line placement, percutaneous lung biopsy, chest tube clamping, or barotrauma such as deep-sea diving or mechanical ventilation.
In the elderly patient presenting with chest pain or shortness of breath, myocardial infarction, pulmonary embolism, aortic dissection, and pneumonia must be ruled out. The workup must include a physical examination with EKG, cardiac enzymes, chest x-ray, and a CT scan of the chest as directed by the findings.
In young women, two additional causes of pneumothorax are lymphangioleiomyomatosis (LAM) and catamenial pneumothorax. LAM, also known as pregnancy pneumothorax, is hormonally driven smooth muscle proliferation along lymphatic channels, which obstructs bronchioles leading to air trapping, bullae formation, and pneumothorax. Catamenial pneumothorax occurs in young women with endometrial tissue in the thorax; the endometriosis forms cysts that can rupture during menses.
Tension pneumothorax, resulting in a mediastinal shift and decreased venous return leading to circulatory collapse, should always be on the differential diagnosis. Any evidence of tracheal deviation on examination requires immediate needle decompression without waiting for a chest x-ray. Confirmation of the diagnosis is found in the audible escape of air under pressure from the thorax. Chest tube placement can then be performed electively. Patients with substantial pneumothorax who require intubation and ventilation should have a small chest tube placed first to prevent conversion to tension pneumothorax when positive pressure ventilation is initiated.
Workup
The patient in this case should first have supplemental oxygen administered and a peripheral intravenous catheter placed. An EKG and chest x-ray are performed that reveal the presence of sinus tachycardia without evidence of acute ischemia and a visible partial collapse of the right lung and pneumothorax without evidence of deviation of the mediastinum, respectively. His oxygen saturations were seen to improve with the administration of supplemental oxygen through nasal cannula. An urgent CT scan of his chest reveals a right-sided pneumothorax, emphysematous changes throughout both lungs, and no evidence of malignancy (Figure 1).
FIGURE 1 • Chest x-ray of right-sided spontaneous pneumothorax.
Discussion
A pneumothorax can be most easily observed on upright chest x-ray (Figure 2). An apex-to-cupola distance of <3 cm is considered a small pneumothorax. One possible error in chest x-ray interpretation is to confuse a skin fold for a pneumothorax. Skin folded against the x-ray cassette appears almost as a vertical line that does not follow the contour of the rib cage. A skin fold has a different radiographic density than a pneumothorax, and vascular markings may be seen lateral to the skin fold.
FIGURE 2 • CT Chest through the midlung showing pneumothorax.
In the patient with preexisting lung disease, a CT scan of the chest can help differentiate among large bullae, cystic lesions, and pneumothoraces, which may appear similar on routine chest x-ray (Figure 3).The CT scan can guide operative management by providing information about underlying lung disease. A CT scan of the chest may be omitted for younger patients with a first presentation of primary spontaneous pneumothorax.
FIGURE 3 • CT Chest through the lung apex showing bulla.
Diagnosis and Treatment
The American College of Chest Physicians published management guidelines in 2001; the goals of management are to treat the pneumothorax, and to reduce the risk of recurrence by achieving visceral and parietal pleural symphysis by means of pleurodesis or pleurectomy.
The risk of recurrence after a first episode of primary spontaneous pneumothorax is estimated at approximately 32%. These patients do not necessarily need surgical treatment or pleurodesis aimed at reducing recurrence unless they have bilateral pneumothoraces or are exposed to significant changes in transpulmonary pressure, such as pilots or divers. An additional indication for surgical management of primary spontaneous pneumothorax includes lack of access to advanced health care or periods of travel distant from adequate health services. The recurrence rate after spontaneous pneumothorax associated with underlying lung disease is approximately 43%, but these patients carry a higher risk of morbidity and mortality due to their baseline respiratory compromise. Operative management or pleurodesis is typically indicated at first presentation. For all patients, the risk of further recurrence increases with each episode. After the second pneumothorax, the recurrence risk is as high as 75% and exceeds 80% after the third pneumothorax. As such, most clinicians recommend intervention following a second episode of pneumothorax.
Clinically stable patients with small primary pneumothoraces can be observed; if the pneumothorax is radiographically stable over 6 hours and there is no progression of symptoms, they may be sent home with follow-up in 1 to 2 days. Most patients with large primary pneumothoraces will be treated with tube thoracostomy or a small “pigtail catheter” placed temporarily to suction. Water seal drainage is sufficient for the vast majority of pneumothoraces. With resolution of the pneumothorax and no evidence of ongoing air leak, the catheter or the tube may be removed and the patient discharged with follow-up in 1 to 2 days. Generally, a 16 to 24 Fr chest tube is sufficient, although patients with a large air leak or receiving mechanical ventilation may require larger chest tubes.
If an air leak persists for more than 3 days, the patient should be evaluated for persistent or recurrent pneumothorax. The patient should be considered for surgical intervention: videoscopic mechanical or talc pleurodesis, blebectomy, or a pleural tenting procedure. Another treatment option for persistent air leak is to perform a blood patch of 50 mL of the patient’s own blood, drawn from the femoral vein, instilled through the chest tube under sterile conditions and flushed with saline. The tube is clamped for 30 minutes and then returned to water seal. This procedure should not be performed if the lung is incompletely re-expanded or if the patient has evidence of infection in the pleural space. The patient should be monitored for conversion to tension pneumothorax during the procedure, as this has been reported.
Patients with pneumothoraces in the setting of severe underlying lung disease should receive prompt evaluation, supplemental oxygen, and receive a small chest tube placed urgently. For loculated or complicated pneumothorax, placement of the chest tube under CT scan guidance may be required. The standard approach to surgical management of pneumothorax is video-assisted thoracoscopic surgery (VATS). In addition to shorter hospital stays, less pain and disability in comparison to open thoracotomy, VATS enjoys similarly high success rates of 95%. Patients who are poor surgical candidates or refuse surgery may be managed with tube thoracostomy and receive bedside pleurodesis through their chest tube.
A novel approach is the use of endobronchial valve technology to specifically obstruct the segmental orifice leading to the site of the classic air leak.
Chemical pleurodesis can be performed by direct instillation of talc or doxycycline into the pleural space. Talc pleurodesis is particularly effective and despite a chronic thickening of the pleura, very few long-term complications have been observed. Talc has rarely been associated with acute lung injury.
Surgical Approach for Bullectomy and Pleurodesis Using VATS
The operation for bleb/bulla resection is similar to a standard wedge resection of the lung using video-scopic technique (Table 1). The patient is intubated with a double-lumen endotracheal tube, which permits single-lung ventilation. Epidural catheters are not generally necessary and the patient is placed in the lateral decubitus position. The operation commences with a thorough bronchoscopy of the tracheobronchial tree. In order to access the lung apex, a camera port is placed at the 5th intercostal space in the anterior-axillary line. Additional instrument ports may be placed in the 4th intercostal space or the 7th intercostal space depending on the location of the pathology. Apical bullae are resected using reinforced, linear GIA staple loads.
TABLE 1. Key Technical Steps for Video-Assisted Thoracosopic Bleb/Bullas Resection and Pleurodesis
The second part of the operation is to create the conditions for pleural symphysis through mechanical or chemical means. The parietal pleura including the diaphragmatic surface can be gently abraded using the electrocautery scratch pad introduced through at VATS incision. Alternate means of mechanical abrasion of the pleura include electrocautery or the argon beam coagulator. Chemical pleurodesis is an important adjunct to mechanical pleurodesis and can be performed with 1 to 5 mg of aerosolized sterile talc evenly distributed to the pleural space.
Pleurectomy is an option for recurrent pneumothorax particularly in younger patients and can be performed through the VATS ports.
Intraoperative Complications
The main intraoperative complication is a large air leak after resection of the tissue. Prior to closure, the lung should be reinflated and examined for persistent air leak. Reinforcing the lung tissue with additional stapling, fibrin glue, or both may be necessary. Approved pulmonary sealants may reduce the risk of air leak. Bleeding and infections in the pleural space represent important potential complications. However, the most common concern is a persistent air leak following resection of diseased tissue.
Intraoperative management issues also include the approach to the “trapped lung.” A lung incapable of expanding to reach the parietal pleural surface creates a judgment challenge for the clinician. If trapped by infection, decortication can be performed, often through open thoracotomy. Patients with trapped lung as a result of carcinoma often can be only managed with a pleural tent.
Postoperative Management
Postoperatively, patients should have a single chest tube, typically 24 or 28 French. The chest tube can be placed to water seal with resolution of the pneumothorax and can be removed on postoperative day 3 should there be no air leak.
If the patient has a persistent air leak after postoperative day 4, then the patient should be placed on to an outpatient suctionless device, such as a Heimlich valve. If the patient can tolerate this device for 24 hours without expansion of the pneumothorax or clinical deterioration, then they may be discharged home with the suctionless device with instructions to call the clinic for any worsening of symptoms. They should follow-up 2 weeks postoperatively; if they have remained asymptomatic on the outpatient suctionless device, they may have the chest tube removed even with a small persistent pneumothorax. Clamping the chest tube is not necessary prior to removal. The patient should have a chest x-ray in 4 hours to demonstrate stability of the pneumothorax.
Complications
Patients should be monitored for arrhythmias, air leaks, chest tube malfunction, or conversion to tension pneumothorax. Additionally, the presence of an air leak can lead to empyema, although this is not common. While empyemas can develop in as little as 2 weeks, the risk of empyema increases with the amount of time the chest tube remains in place. Antibiotics have not been shown to reduce empyema risk when given longer than 24 hours after surgery.
Fibrin deposition on an incompletely expanded lung can begin as soon as 7 days after lung collapse, creating a fibrous rind that may require decortication. Patients with infections of the pleural space are at risk of developing a trapped lung.
Particular attention to pain management is important as respiratory compromise, such as atelectasis or pneumonia, is common in patients with poor pain control and hypoventilation.
TAKE HOME POINTS
· A first presentation of a spontaneous pneumothorax should be managed based on size and clinical presentation with either observation or tube thoracostomy.
· All patients with pneumothorax due to significant underlying lung disease should be admitted and most should have operative management to reduce their recurrence risk.
· VATS is now the standard operative approach for bullectomy and pleurodesis.
· For nonoperative and postoperative patients, place chest tubes to water seal as soon as possible.
· Clinically stable patients with persistent air leaks postoperatively can be discharged home with an outpatient suctionless device and seen back in clinic in 2 weeks.
Acknowledgments
Our thanks to Dr. Brett Elicker, UCSF, for the radiographic images.
SUGGESTED READINGS
Baumann MH, Strange C, Heffner JE, et al. Management of spontaneous pneumothorax: An American College of Chest Physicians Delphi Consensus Statement. Chest. 2001;119:590–602.
Cerfolio RJ, Minnich DJ, Bryant AS. The removal of chest tubes despite an air leak or a pneumothorax. Ann Thorac Surg. 2009;87(6):1690–1694; discussion 1694–1696.