31 General Thoracic Surgery - Bài viết - Bệnh Học
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31 General Thoracic Surgery

Cho điểm
General Thoracic Surgery
Felix G. Fernandez
Richard J. Battafarano
Thoracic surgery encompasses the management of both benign and malignant conditions of the esophagus, lung, pleura, and mediastinum. In this chapter, we focus on the systematic evaluation and treatment of the most common conditions. Disease processes of the esophagus are discussed in Chapter 8.
I. Lung Cancer
Cancer of the lung remains the leading cause of cancer death in the United States. Approximately 173,000 cases of lung cancer were diagnosed in 2005, and more than 164,000 people died from this disease. Most newly diagnosed cases are not amenable to surgical resection and have poor prognosis. Lung cancer carries an overall 15% 5-year survival. Cigarette smoking remains the leading risk factor and influences risk stratification in the evaluation of a suspicious lesion. Increasing age also increases the probability of malignancy. Although trials conducted more than two decades ago to screen for lung cancer by either sputum cytology or chest x-ray imaging failed to show benefit, annual spiral computed tomography (CT) scanning can detect lung cancers that are curable (N Engl J Med 2006;355:1822). However, questions remain as to whether the test is sufficiently effective to justify screening people at high risk for lung cancer.

  • Radiographic presentation
    • Solitary pulmonary nodule (SPN). Due to the widespread application of CT technology, an estimated 150,000 SPNs are diagnosed each year. By definition, these are circumscribed lung lesions in an asymptomatic individual. Lesions greater than 3 cm are called masses.
    • Radiographic imaging by CT is used to both follow these lesions and predict outcome. The first step in the evaluation of an SPN is to evaluate any prior films. Factors favoring a benign lesion include absence of growth over a 2-year period, size of the lesion, and pattern of calcification. Calcifications that are diffuse, centrally located, “onion skinned” (laminar), or popcornlike are generally benign. Eccentric or stippled calcifications may indicate malignancy. Lesion greater than 2 cm, intravenous contrast enhancement, or irregular borders predict malignancy.
    • Positron emission tomography (PET) scanning has demonstrated 95% sensitivity and 80% specificity in characterizing solitary pulmonary nodules. PET imaging has a high negative predictive value for most lung cancers; however, bronchoalveolar carcinoma and carcinoid tumor can be negative by PET scan, and inflammatory and infectious processes can be falsely positive. The patient's overall risk factor profile must be considered. In the setting of low risk (e.g., young age, nonsmoker, favorable features on CT), a negative PET scan has a high negative predictive value, but the same result in an elderly smoker is less reassuring, and further evaluation is warranted.
    • Tissue biopsy remains the gold standard for diagnosis. Tissue may be obtained by bronchoscopy in patients with central lung lesions or by CT-guided biopsy. This latter technique has an 80% sensitivity for a malignant process and requires technical expertise. Surgical biopsy of SPN by either minimally invasive techniques or open technique can provide a definitive diagnosis and definitive treatment.

  • Pathology

The two main classes of lung tumors are small-cell (oat cell) carcinoma and non–small-cell carcinoma.

    • Small-cell carcinoma accounts for approximately 20% of all lung cancers. It is highly malignant, usually occurs centrally near the hilum, occurs almost exclusively in smokers, and rarely is amenable to surgery because of wide dissemination by the time of diagnosis. These cancers initially respond to chemotherapy, but overall 5-year survival remains 10%.
    • Non–small-cell carcinomas account for 80% of all lung cancers and make up the vast majority of those treated by surgery. The three subtypes are adenocarcinoma (30% to 50% of cases), squamous cell (20% to 35%), and large cell (4% to 15%). Most tumors are histologically heterogeneous, possibly indicating common origin. Bronchioloalveolar carcinoma is a variant of adenocarcinoma and is known for its ability to produce mucin and its multifocal nature. Over the last decade, it has been appreciated that carcinoid tumors (grade I), atypical carcinoid tumors (grade II), large-cell carcinoma, and small-cell tumors represent important subgroups of bronchogenic neuroendocrine carcinoma. This may explain the more aggressive behavior of large-cell carcinoma relative to other non–small-cell cancers.

  • Symptomatic presentation of lung cancer implies a worsening stage and is associated with an overall lower rate of survival.
    • Bronchopulmonary features include cough or a change in a previously stable smoker's cough, increased sputum production, dyspnea, and new wheezing. Minor hemoptysis causing blood-tinged sputum, even as an isolated episode, should be investigated with flexible bronchoscopy, especially in patients with a history of smoking who are 40 years of age or older. Lung cancer may also present with postobstructive pneumonia.
    • Extrapulmonary thoracic symptoms include chest wall pain secondary to local tumor invasion, hoarseness from invasion of the left recurrent laryngeal nerve near the aorta and left main pulmonary artery, shortness of breath secondary to malignant pleural effusion, and superior vena cava syndrome causing facial, neck, and upper-extremity swelling. Pancoast tumor (superior sulcus tumor) can lead to brachial plexus invasion, as well as invasion of the cervical sympathetic ganglia, which causes an ipsilateral Horner syndrome (ptosis, miosis, and anhidrosis). Rarely, lung cancer can present as dysphagia secondary to compression or invasion of the esophagus by mediastinal nodes or by the primary tumor.

The most frequent sites of distant metastases include the liver, bone, brain, adrenal glands, and the contralateral lung. Symptoms may include pathologic fractures and arthritis from bony involvement. Brain metastasis may cause headache, vision changes, or changes in mental status. Adrenal involvement infrequently presents with Addison disease. Lung cancer is the most common tumor causing adrenal dysfunction.

    • Paraneoplastic syndromes are frequent and occur secondary to the release of hormonelike substances by tumor cells. They include Cushing syndrome (adrenocorticotropic hormone secretion in small-cell carcinoma), syndrome of inappropriate antidiuretic hormone (SIADH), hypercalcemia (parathyroid hormone–related protein secreted by squamous cell carcinomas), hypertrophic pulmonary osteoarthropathy (clubbing of the fingers, stiffness of joints, and periosteal thickening on x-ray), and various myopathies.

  • Accurate clinical and pathologic staging is critical in the management of patients with non–small-cell carcinoma because surgery is the primary mode of therapy for all stage I and II patients and selected stage IIIa patients who have enough physiologic reserve to tolerate resection. It is critical to exclude metastatic disease prior to resection. The essential elements of staging include evaluation for lymph node involvement and evaluation for adrenal, brain, and bone metastasis. An anatomic staging system using the classification for tumor, nodal, and metastatic status was most recently modified in 1997 (Table 31-1).

TABLE 31-1 American Joint Committee on Cancer Staging System of Lung Cancer
Tumor status (T)
<3 cm without invasion of visceral pleura proximal to lobar bronchus
>3 cm or any size with associated atelectasis or obstructive pneumonitis that does not involve the entire lung; may invade visceral pleura; proximal extent must be >2 cm from carina
Any size with direct extension into chest wall, diaphragm, mediastinal pleura, or pericardium without involvement of great vessels or vital mediastinal structures; cannot involve carina; atelectasis or obstructive pneumonitis of the entire lung
Any size with invasion of heart or mediastinal vital structures or carina, malignant pleural effusion, satellite lesions
Nodal involvement (N)
Peribronchial or ipsilateral hilar lymph nodes
Ipsilateral mediastinal lymph nodes, including subcarinal
Contralateral mediastinal or hilar lymph nodes, ipsilateral or contralateral scalene or supraclavicular lymph nodes
Distant metastases (M)
Distant metastases present
T1 N0 M0
T2 N0 M0
T1 N1 M0
T2 N1 M0; T3 N0 M0
T3 N1 M0; T1,2,3 N2 M0
Any T N3 M0; T4, any N, M0
Any T, any N, M1
Reprinted with permission from Fleming ID, Cooper JS, Henson DE, et al., eds. AJCC Cancer Staging Manual, 5th ed. Philadelphia: Lippincott Williams & Wilkins; 1998.

    • Chest CT to include the upper abdomen provides useful information on location, size, and local involvement of tumor and also allows evaluation for liver and adrenal metastasis. CT scanning alone does not accurately determine the resectability of tumor adherent to vital structures. Patients with localized disease may require intraoperative staging to determine resectability. CT also can identify mediastinal lymphadenopathy. However, the sensitivity for identifying metastatic lymph nodes by CT is only 65% to 80% and the specificity is only 65%. With nodes larger than 1 cm, the sensitivity decreases but the specificity increases.
    • PET imaging is often used in the staging of patients with non–small-cell carcinoma, but its accuracy for detecting primary tumors and metastatic disease may be limited by the presence of inflammation and ongoing infection. In regions endemic for inflammatory processes such as histoplasmosis, the usefulness of PET imaging for investigating mediastinal lymph nodes is limited. However, it can be useful for identifying occult distant metastatic disease to the liver, adrenals, and bone.
    • Mediastinoscopy is the most accurate method for staging mediastinal lymph nodes, and it provides access to the pretracheal, subcarinal, and paratracheal node stations. Although invasive, it is safe, with less than a 1% complication rate. We favor the routine use of this technique in the staging of patients with non–small-cell carcinoma, with the exception of patients with clinical stage I lung cancer staged by CT and PET, who benefit little from mediastinoscopy (J Thorac

Cardiovasc Surg 2006;131:822). The timing of mediastinoscopy, whether at the time of thoracotomy or before a planned resection, is controversial and depends on the surgeon's preference and the availability of expert pathologic evaluation of mediastinal lymph node frozen sections.

    • CT or magnetic resonance (MR) imaging of the brain to identify brain metastases is mandatory in the patient with neurologic symptoms but is controversial as a routine part of the workup of symptomatic patients. Given the reported, albeit low, incidence of CNS metastasis in the setting of even small primary tumors, we advocate the routine use of brain imaging.
    • Bone scan is obtained in all patients with specific symptoms of skeletal pain and selectively as part of the preoperative metastatic workup. The routine use of PET imaging in many centers has eliminated the need for this modality.
    • Fiberoptic bronchoscopy is important in diagnosing and assessing the extent of the endobronchial lesion. Although peripheral cancers rarely can be seen with bronchoscopy, preoperative bronchoscopy is important for excluding synchronous lung cancers (found in approximately 1% of patients) prior to resection. Bronchial washings with culture can be taken at the time of bronchoscopy in patients with significant secretions.

  • Preoperative assessment of pulmonary function and estimation of postoperative pulmonary assessment is the most critical factor in planning lung resection for cancer.
    • Pulmonary function tests and arterial blood gas analysis are the standard by which the risk of developing postoperative pulmonary failure is determined. In general, pulmonary resection can be tolerated if the preoperative FEV1 (forced expiratory volume in 1 second) is greater than 60% of predicted. If the FEV1 is less than 60% of predicted, measurement of diffusion capacity, quantitative ventilation-perfusion scan, and exercise testing are indicated. These tests allow the surgeon to determine how much of the area of resection contributes to the overall pulmonary function. In general, an estimated postresection FEV1 of 800 cc or greater suggests that the patient will tolerate a pneumonectomy. Preoperative hypercapnia (arterial carbon dioxide tension >45 mm Hg) precludes resection.
    • Evaluation of cardiac disease is critical for minimizing perioperative complications. Patients with lung cancer are often at high risk for coronary disease because of extensive smoking histories. A detailed history and physical examination to elicit signs and symptoms of ischemia and a baseline electrocardiogram (ECG) are the initial steps. Any abnormal findings should be aggressively pursued with stress tests or coronary catheterization.
    • Smoking cessation preoperatively for as little as 2 weeks can aid in the regeneration of the mucociliary function and pulmonary toilet and has been associated with fewer postoperative respiratory complications.

  • In summary, all patients should have a posteroanterior and lateral chest x-ray and a chest CT scan to evaluate the primary tumor and the mediastinum and to check for metastatic disease to the brain and adrenals. PET imaging or bone scan is required to exclude bone metastasis. Cervical mediastinoscopy with biopsy of the lymph nodes in the paratracheal and subcarinal space should be performed to exclude mediastinal lymph node metastasis prior to resection, except possibly in patients with clinical stage I disease. All patients should undergo a fiberoptic bronchoscopy by the surgeon before thoracotomy; this is usually done at the same setting as mediastinoscopy.
  • Operative principles. In the patient able to tolerate resection, the minimal extent of resection should be an anatomic lobectomy. Even in stage I disease, a more limited resection, such as a wedge resection, results in a threefold higher incidence of local recurrence and a decreased overall and disease-free survival. Patients with limited pulmonary reserve may be treated by segmental or wedge resection. Most centers report operative mortality of 2% to 3% with lobectomy and of 6% to 8% with pneumonectomy. Minimally invasive techniques for anatomic resection are in clinical trial.
  • Five-year survival rates are 67% for stage Ia (T1N0) disease and 57% for stage Ib (T2N0) disease. Stage I disease is generally treated with surgical resection alone. The presence of ipsilateral intrapulmonary lymph nodes decreases the overall survival to 55% for stage IIa (T1N1) disease and 39% for stage IIb (T2N1) disease. Stage II cancers are also treated with surgical resection. However, adjuvant chemotherapy has been associated with improved 5-year survival and is now routinely recommended in patients with stage II or stage III disease. Adjuvant radiation therapy is considered in patients with close surgical margins or central N1 lymph node metastasis.

Certain patients with stage IIIa disease appear to benefit form surgical resection alone (T3N1M0). However, selected patients with mediastinal lymph node metastasis (N2 disease) may be candidates for surgical resection after neoadjuvant chemoradiation therapy. Patients with bulky, diffuse mediastinal lymphadenopathy are often treated using definitive chemoradiation. The optimal regimen of chemotherapy, radiation, or a combination of both is being investigated in clinical trials. Stage IIIb tumors involve the contralateral mediastinal or hilar lymph nodes, the ipsilateral scalene or supraclavicular lymph nodes, extensive mediastinal invasion, intrapulmonary metastasis, or malignant pleural effusions. These tumors are considered unresectable. Stage IV tumors have distant metastases and are also considered unresectable. However, selected patients with node-negative lung cancer and a solitary brain metastasis have achieved long-term survival with combined resection.
II. Tumors of the Pleura
The most common tumor of the pleura is the rare but deadly mesothelioma. Less common tumors include lipomas, angiomas, soft-tissue sarcomas, and fibrous histiocytomas.
A. Asbestos
Asbestos exposure is associated with mesothelioma 70% of the time. Mesotheliomas arise from mesothelial cells but differentiate into a variety of histologic patterns. It is often difficult to differentiate mesothelioma from other tumors without the benefit of special stains or immunohistochemistry.
B. Epidemiologically
Epidemiologically, mesothelioma is primarily a disease of men in the fifth through seventh decades of life. Patients may have been exposed to asbestos decades before (latency >30 years). Patient presentation may be variable. Although benign mesothelioma variants are not associated with asbestos exposure and are asymptomatic, patients with the more common malignant form often report chest pain, malaise, cough, weakness, weight loss, and shortness of breath with pleural effusion. One third of patients report paraneoplastic symptoms of osteoarthropathy, hypoglycemia, and fever.
C. CT scan
CT scan is useful in differentiating pleural from parenchymal disease. Malignant mesothelioma usually appears as a markedly thickened, irregular, pleural-based mass or nodular pleura with a pleural effusion. Occasionally, only a pleural effusion is seen. Routine use of MR imaging has not been shown to have significant advantages over use of CT. However, it has been useful for identifying transdiaphragmatic extension of tumor into the abdomen.
D. Diagnosis
Diagnosis based purely on cytology of thoracentesis sample is difficult. Thoracoscopic or open pleural biopsy is usually necessary to confirm the diagnosis.
E. Classification
Classification is based on histologic evaluation: Epithelial, sarcomatous, and mixed forms have been identified.
F. Median survival
Median survival in untreated patients with malignant mesothelioma is 4 to 12 months. Patients with mixed or sarcomatous mesothelioma have a poor prognosis and do not appear to benefit from surgical resection. Current aggressive multimodality therapy consists of pleurectomy and decortication or extrapleural pneumonectomy to decrease tumor mass, followed by chemotherapy and radiotherapy. Adjuvant therapy is not beneficial in the setting of incomplete resection. However, patients with epithelial histology, no evidence of lymph node metastasis, and complete resection appear to benefit from an aggressive combined modality approach. The most encouraging studies report a 5-year survival of 39%.
III. Tumors of the Mediastinum
The location of a mass in relation to the heart helps the surgeon to form a differential diagnosis (Table 31-2). On the lateral chest x-ray, the mediastinum is divided into thirds, with the heart comprising the middle segment.
TABLE 31-2 Differential Diagnosis of Tumors Located in the Mediastinum
Congenital cyst
Germ cell
Primary cardiac
Neural crest
Aberrant thyroid
Modified from Young RM, Kernstine KH, Corson JD. Miscellaneous cardiopulmonary conditions. In: Corson JD, Williamson RCN, eds. Surgery. Philadelphia: Mosby; 2001.
A. Epidemiology
In the totality of all age groups, lymphoma is the most common mediastinal tumor. Neurogenic tumors are more likely in children. The likelihood of malignancy is greatest in the second to fourth decades of life. The presence of symptoms is more suggestive of a malignant lesion. Symptoms are often nonspecific and include dyspnea, cough, hoarseness, vague chest pain, and fever.
B. Evaluation
Chest x-ray is often used as a screening tool and can lead to the diagnosis of a mass. This should be followed by a CT scan to further delineate the anatomy.
C. Tumors
Due to the prevalence of germ cell tumors, all anterior mediastinal masses should be evaluated with biochemical markers β-human chorionic gonadotropin (β-HCG) and α-fetoprotein (AFP).

  • Teratomas are usually benign and often contain ectodermal components such as hair, teeth, and bone. Elevation of both β-HCG and AFP suggests a malignant teratoma. Treatment is surgical resection.
  • Seminomas do not present with an elevation in AFP, and fewer than 10% present with an elevation in β-HCG. Their treatment is primarily nonsurgical (radiation and chemotherapy), except in the case of localized disease.
  • Nonseminomatous germ cell tumors present with an elevation of both tumor markers. Again, the treatment is primarily nonsurgical, with the exception of obtaining tissue for diagnosis.
  • Tissue diagnosis is often crucial for the diagnosis and treatment of lymphoma. Treatment is primarily nonsurgical. Cervical lymph node biopsy, CT-guided biopsy, or mediastinoscopy with biopsy may be required. These lesions often present as irregular masses on CT scan.
  • Patients with paravertebral or posterior mediastinal masses should have their catecholamine levels measured to rule out pheochromocytomas.

IV. Thymectomy/Thymoma

  • The role of the thymus gland in myasthenia gravis is poorly understood. However, it appears to be important in the generation of autoreactive antibodies directed against the acetylcholine receptor. Anti–acetylcholine-receptor antibodies may be used to evaluate for myasthenia gravis. Greater than 80% of cases demonstrate complete or partial response to thymectomy. Chances of improvement are increased if thymectomy is performed early in the course of disease (first signs of muscle weakness) and if the myasthenia is not associated with a thymoma.
  • A thymoma is a focal mass in the thymus gland composed primarily of thymic epithelial cells. Most are benign, but the presence of invasion of its fibrous capsule defines malignancy. Whereas 15% of myasthenia gravis patients have a

thymoma, approximately 50% of patients with a thymoma have paraneoplastic syndromes, including myasthenia gravis, hypogammaglobulinemia, and red cell aplasia.

  • Preoperative preparation of the patient with myasthenia gravis involves reduction of corticosteroid dose, if appropriate, and the weaning of anticholinesterases. Plasmapheresis can be performed preoperatively to aid in discontinuation of anticholinesterase agents. Muscle relaxants and atropine should be avoided during anesthetic induction.
  • The operative approach for thymectomy for myasthenia in cases in which noninvasive imaging does not indicate the presence of a thymoma or a mass lesion is controversial. The options range from median sternotomy to a transcervical thymectomy. The transcervical approach involves a low collar incision and is facilitated by using a table-mounted retractor to elevate the manubrium and expose the thymic tissue for resection. The transcervical approach has lower morbidity, but there are questions as to whether it is as efficacious as the transsternal approach.
  • In instances of bulky thymic disease, a median sternotomy approach is preferred to provide maximal exposure for complete resection.

V. Pneumothorax

  • Pneumothorax is the presence of air in the pleural cavity, leading to separation of the visceral and parietal pleura. This disruption of the potential space disrupts pulmonary mechanics, and, if left untreated, it may progress to tension physiology. In tension pneumothorax, cardiac compromise occurs and presents a true emergency. The etiology may be spontaneous, iatrogenic, or due to trauma. The etiology will determine the most appropriate short- and long-term management strategies.
  • Physical examination may demonstrate decreased breath sounds on the involved side if the lung is more than 25% collapsed. Hyperresonance on the affected side is possible. Common symptoms include dyspnea and chest pain. Careful examination for signs of tension pneumothorax (including deviation of the trachea to the opposite side, respiratory distress, and hypotension) must be performed. If there is no clinical evidence of tension pneumothorax, an upright chest x-ray will be required to establish the diagnosis. Smaller pneumothoraces may only be evident on expiration chest x-rays or CT scan. The clinical setting will influence their management.
  • Management options include observation, aspiration, chest tube placement with or without pleurodesis, and surgery. The etiology of the pneumothorax influences management strategy.
    • Observation is an option in a healthy, asymptomatic patient. This should be reserved for small pneumothoraces, unlikely to recur, because failure to fully resolve may lead to fibrous entrapment of the lung. Supplemental oxygen may help to reabsorb the pneumothorax by affecting the gradient of nitrogen in the body and in the pneumothorax.
    • Aspiration of the pneumothorax may be done using a small catheter attached to a three-way stopcock. This should be reserved for situations with low suspicion of an ongoing air leak.
    • Percutaneous catheters may be placed using Seldinger technique. Multiple commercial kits exist and allow for the catheter to be placed to a Heimlich valve or to suction. The catheters in these kits are generally of small caliber, and their use is limited to situations of simple pneumothorax.
    • Tube thoracostomy remains the gold standard, especially for larger pneumothoraces, for persistent air leaks, when there is an expected need for pleurodesis, or for associated effusion.
      • Chest tubes may be connected either to a Heimlich flutter valve, to a simple underwater-seal system, or to vacuum suction. The two most commonly used systems are the Pleurovac and Emerson systems. Both systems may be placed to a water seal (providing –3-cm to –5-cm H2O suction) or to vacuum suction (typically –20 cm).
      • If the water-seal chamber bubbles with expiration or with coughing, this is evidence that an air leak persists. Newer Pleurovac systems allow as much as –40-cm H2O suction to be applied to the pleural space.

    • Bedside pleurodesis. Sclerosing agents may be administered through the chest tube to induce fusion of the parietal and visceral pleural surfaces. Doxycycline, bleomycin, and talc have all been described.
      • Bedside pleurodesis can be associated with an inflammatory pneumonitis in the lung on the treated side. In patients with limited pulmonary reserve, this may present as clinically significant hypoxia. Pleurodesis can be quite uncomfortable for the patient, and adequate analgesia is mandatory. Patient-controlled analgesic pump and bolus administration of ketorolac (if tolerated) are effective.
      • Doxycycline is used as the sclerosing agent for benign processes.
        • It is administered as 500 mg in 100 mL of normal saline. Doxycycline is extremely irritating to the pleural surfaces; therefore, 30 mL of 1% lidocaine can be administered via the chest tube before the doxycycline is given and used to flush the drug again. The total dose of lidocaine should not exceed the toxic dose, which is usually 5 mg/kg.
        • In patients with large air leaks, the chest tube should not be clamped, to prevent the development of a tension pneumothorax. Instead, the drainage bottle or suction device should be elevated to maintain the effective water-seal pressure at –20 cm H2O.
        • The patient (with assistance) is instructed to roll from supine to right lateral decubitus to left lateral decubitus every 15 minutes for 2 hours. Prone, Trendelenburg, and reverse Trendelenburg positions should also be part of the sequence if the patient is able to tolerate it.
        • The chest tube may be unclamped (if done for the procedure) and returned to suction after the procedure.

      • Talc is a less painful sclerosing agent. Due to concern about introducing a potentially carcinogenic agent and permanent foreign body, it is generally limited to patients with underlying malignant conditions (see Effusions, Section VII.A.4.a).
        • Talc, 5 g in 180 mL of sterile saline split into 360-mL catheter syringes, is administered via the chest tube and then flushed with an additional 60 mL of saline.
        • The patient is instructed to change positions as described previously.

    • Surgery is performed using a video-assisted approach or by thoracotomy. Patients who have a persistent air leak secondary to a ruptured bleb but are otherwise well should be considered for surgery. By this point, patients have already undergone stabilization by chest tube placement (see Section V.D.3 for specific indications for surgery).

  • Etiology
    • Iatrogenic pneumothoraces usually are the result of pleural injury during central venous access attempts, pacemaker placement, or transthoracic or transbronchial lung biopsy. A postprocedure chest x-ray is mandatory. Often the injury to the lung is small and self-limited. The extent of pneumothorax and associated injury should determine the need for invasive procedures. Observation or percutaneous placement of a chest tube may be appropriate in a patient who is not mechanically ventilated.
    • Spontaneous pneumothorax is nearly always caused by rupture of an apical bleb. Up to 80% of patients are tall, young adults, and men outnumber women by 6 to 1; it is more common in smokers than in nonsmokers. The typical patient presents with acute onset of shortness of breath and chest pain on the side of the collapsed lung. Patients older than 40 years usually have significant parenchymal disease, such as emphysema. These patients present with a ruptured bulla and often have a more dramatic presentation, including tachypnea, cyanosis, and hypoxia. There is a significant risk of recurrence, and pleurodesis or surgical intervention may be indicated even after the first occurrence. Other etiologies of spontaneous pneumothorax include cystic fibrosis and, rarely, lung cancer.
    • Indications for operation for spontaneous pneumothorax include (1) recurrent ipsilateral pneumothoraces, (2) bilateral pneumothoraces, (3) persistent air leaks

on chest tube suction (usually >5 days), and (4) first episodes occurring in patients with high-risk occupations (e.g., pilots, divers) or those who live a great distance from medical care facilities. The risk of ipsilateral recurrence of a spontaneous pneumothorax is 50%, 62%, and 80% after the first, second, and third episodes, respectively. Some authors recommend chemical pleurodesis as the minimal therapy for the first occurrence.
Operative management consists of stapled wedge resection of blebs or bullae, usually found in the apex of the upper lobe or superior segment of the lower lobe. Pleural abrasion (pleurodesis) should be done to promote formation of adhesions between visceral and parietal pleurae. Video-assisted thoracoscopic techniques have allowed procedures to be less morbid in most cases. Using three small port incisions on the affected side, thoracoscopic stapling of the involved apical bulla and pleurodesis can be done. Alternatively, a transaxillary thoracotomy incision gives excellent exposure of the upper lung through a limited incision.

    • Traumatic pneumothoraces may be caused by either blunt or penetrating thoracic trauma and often result in lung contusion and multiple rib injury.
      • Evaluation and treatment begin with the initial stabilization of airway and circulation. A chest x-ray should be obtained.
      • Prompt chest tube insertion is performed to evacuate air and blood. In 80% of patients with penetrating trauma to the hemithorax, exploratory thoracotomy is unnecessary, and chest tube decompression with observation is sufficient. Indications for operation include immediate drainage of greater than 1,500 mL of blood after tube insertion or persistent bleeding of greater than 200 mL/hour. Patients who have with multiple injuries and proven pneumothoraces or significant chest injuries should have prophylactic chest tubes placed before general anesthesia because of the risk of tension pneumothorax with positive-pressure ventilation.
      • Pulmonary contusion is associated with traumatic pneumothorax. The contusion usually is evident on the initial chest x-ray (as opposed to aspiration, in which several hours may elapse before an infiltrative pattern appears on serial radiographs), and it appears as a fluffy infiltrate that progresses in extent and density over 24 to 48 hours.
      • The contusion may be associated with multiple rib fractures, leading to a flail chest. This occurs when several ribs are broken segmentally, allowing for a portion of the chest wall to be “floating” and to move paradoxically with breathing (inward on inspiration). The paradoxical movement and splinting secondary to pain and the associated pain lead to a reduction in vital capacity and to ineffective ventilation.
      • All patients with suspected contusions and rib fractures should have aggressive pain control measures, including patient-controlled analgesia pumps, epidural catheters, and/or intercostal nerve blocks.
      • Intravenous fluid should be minimized to the extent allowed by the patient's clinical status because of associated increased capillary endothelial permeability. Serial arterial blood gas measurements are important for close monitoring of respiratory status. Close monitoring and a high index of suspicion for respiratory decompensation are necessary. Intubation, positive-pressure ventilation, and even tracheostomy are often necessary.
      • A traumatic bronchopleural fistula can occur after penetrating or blunt chest trauma. If mechanical ventilation is ineffective secondary to the large air leak, emergent thoracotomy and repair are usually necessary. On occasion, selective intubation of the uninvolved bronchus can provide short-term stability in the minutes before definitive operative treatment.
      • The unusual circumstance known as a sucking chest wound consists of a full-thickness hole in the chest wall greater than two thirds the diameter of the trachea. With inspiration, air preferentially flows through the wound because of the low resistance to flow. This requires immediate coverage of the hole with an occlusive dressing and chest tube insertion to reexpand the

lung. If tube thoracostomy cannot be immediately performed, coverage with an occlusive dressing taped on three sides functions as a one-way valve to prevent the accumulation of air within the chest, although tube thoracostomy should be performed as soon as possible.
VI. Hemoptysis
Hemoptysis can originate from a number of causes, including infectious, malignant, and cardiac disorders (e.g., bronchitis or tuberculosis, bronchogenic carcinoma, and mitral stenosis, respectively).
A. Massive hemoptysis
Massive hemoptysis requires emergent thoracic surgical intervention, often with little time for formal studies before entering the operating room. The surgeon is called primarily for significant hemoptysis, which is defined as more than 600 mL of blood expelled over 48 hours or, more often, a volume of blood that is impairing gas exchange. Because the volume of the main airways is approximately 200 mL, even smaller amounts of blood can cause severe respiratory compromise. Prompt treatment is required to ensure survival. As baseline lung function decreases, a lower volume and rate of hemoptysis is capable of severely compromising gas exchange.
  • A brief focused history can often elucidate the etiology of the bleed, such as a history of tuberculosis or aspergillosis. A recent chest x-ray may reveal the diagnosis in up to half of cases. Chest CT is rarely helpful in the acute setting and is contraindicated in patients who are unstable. Trace amounts of hemoptysis can be evaluated by radiologic examinations in conjunction with bronchoscopy.
  • Bronchoscopy is the mainstay of diagnosis and initial treatment. Although it may not eliminate later episodes of bleeding, it can allow for temporizing measures, such as placement of balloon-tipped catheters and topical or injected vasoconstrictors. In a setting of massive hemoptysis, the patient should be prepared for a rigid bronchoscopy, which is best performed in the operating room under general anesthesia. Asphyxiation is the primary cause of death in patients with massive hemoptysis. Rigid bronchoscopy allows for rapid and effective clearance of blood and clot from the airway, rapid identification of the bleeding side, and prompt protection of the remaining lung parenchyma (with cautery, by packing with epinephrine-soaked gauze, or by placement of a balloon-tipped catheter in the lobar orifice).
  • In cases in which the etiology and the precise bleeding source are not identified by bronchoscopy, ongoing bleeding requires protection of the contralateral lung. Selective ventilation, either with a double-lumen tube or by direct intubation of the contralateral main-stem bronchus, may be critical to avoid asphyxiation.
  • After isolation of the bleeding site, angiographic embolization of a bronchial arterial source may allow for lung salvage without the need for resection. The bronchial circulation is almost always the source of hemoptysis. Bleeding from the pulmonary circulation is seen only in patients with pulmonary hypertension.
  • Definitive therapy may require thoracotomy with lobar resection or, rarely, pneumonectomy. Infrequently, emergent surgical resection is necessary to control the hemoptysis. The etiology of the bleeding and the pulmonary reserve of the patient are important because many patients are not candidates for surgical resection.

VII. Pleural Effusion

  • Pleural effusion may result from a wide spectrum of benign, malignant, and inflammatory conditions. By history, it is often possible to deduce the etiology, but diagnosis often depends on the analysis of the pleural fluid. The presentation of symptoms depends on the underlying etiology, and treatment is based on the underlying disease process.

    • Chest x-ray is often the first diagnostic test. Depending on radiographic technique, an effusion may remain hidden. Although decubitus films are the most sensitive for detecting small, free-flowing effusions, the same volume may remain hidden in a standard anteroposterior film. A concave meniscus in the costophrenic angle on an upright chest x-ray suggests at least 250 mL of pleural fluid. CT scan and ultrasound can be particularly helpful if the fluid is not

free flowing or if history suggests a more chronic organizing process such as empyema.

    • Thoracentesis
      • The technique of thoracentesis is described in Chapter 37.
      • The fluid should be sent for culture and Gram stain, biochemical analyses [pH, glucose, amylase, lactate dehydrogenase (LDH), and protein levels], and a differential cell count and cytology to rule out malignancy.
      • In general, thin, yellowish, clear fluid is common with transudative effusions; cloudy and foul-smelling fluid usually signals infection or early empyema; bloody effusions often denote malignancy; milky white fluid suggests chylothorax; and pH less than 7.2 suggests bacterial infection or connective tissue disease.
      • Larger volumes (several hundred milliliters) can often aid the cytopathologists in making a diagnosis. White blood cell count greater than 10,000/mm3 suggests pyogenic etiology. A predominance of lymphocytes is noted with tuberculosis. Glucose is decreased in infectious processes as well as in malignancy.
      • Pleural effusions are broadly categorized as either transudative (protein-poor fluid not involving primary pulmonary pathology) or exudative (resulting from increased vascular permeability as a result of diseased pleura or pleural lymphatics). Protein and LDH levels measured simultaneously in the pleural fluid and serum provide the diagnosis in nearly all settings.
      • Exudative pleural effusions satisfy at least one of the following criteria: (1) ratio of pleural fluid protein to serum protein greater than 0.5, (2) ratio of pleural fluid LDH to serum LDH greater than 0.6, or (3) pleural fluid LDH greater than two thirds the upper normal limit for serum.

    • Transudative pleural effusion can usually be considered a secondary diagnosis; therefore, therapy should be directed at the underlying problem (e.g., congestive heart failure, cirrhosis, or nephrotic syndrome). Therapeutic drainage is rarely indicated because fluid rapidly reaccumulates unless the underlying cause improves.
    • Exudative pleural effusion may be broadly classified based on whether its cause is benign or malignant.
      • Malignant effusions are most often associated with cancers of the breast, lung, and ovary and with lymphoma. Diagnosis is often made by cytology, but in the event that this process is not diagnostic, pleural biopsy may be indicated. Given the overall poor prognosis in these patients, therapy offered by the thoracic surgeon is generally palliative.

        • Drainage of effusion to alleviate dyspnea and improve pulmonary mechanics by reexpanding the lung may be done with chest tube placement.
        • Pleurodesis with talc or doxycycline may prevent reaccumulation of the effusion.

      • Benign exudative effusions are most often a result of pneumonia (parapneumonic). The process begins with a sterile parapneumonic exudative effusion and leads to a suppurative infection of the pleural space, empyema, if the effusion becomes infected. The initially free-flowing fluid becomes infected and begins to deposit fibrin and cellular debris (5 to 7 days). Eventually, this fluid becomes organized, and a thick, fibrous peel entraps the lung (10 to 14 days).
        • Empyema. Fifty percent of empyemas are complications of pneumonia; 25% are complications of esophageal, pulmonary, or mediastinal surgery; and 10% are extensions from subphrenic abscesses. Thoracentesis is diagnostic but is sufficient treatment in only the earliest cases.
        • The clinical presentation of empyema ranges from systemic sepsis requiring emergent care to chronic loculated effusion in a patient who complains of fatigue. Other symptoms include pleuritic chest pain, fever, cough, and dyspnea.
        • The most common offending organisms are Gram-positive cocci (Staphylococcus aureus and streptococci) and Gram-negative organisms (Escherichia coli and Pseudomonas and Klebsiella species). Bacteroides species are also common.
        • Management includes control of the infection by appropriate antibiotics, drainage of the pleural space, and obliteration of the empyema space. Once the diagnosis is made, treatment should not be delayed. Specific management depends on the phase of the empyema, which depends on the character of the fluid. If the fluid does not layer on posteroanterior and lateral and decubitus chest x-ray, a CT scan should be done.

          • Early or exudative empyema is usually adequately treated with simple tube drainage.
          • Fibropurulent empyema may be amenable to tube drainage alone, but the fluid may be loculated. The loculations of empyema cavities are composed of fibrin.
          • In advanced or organizing empyema, the fluid is thicker and a fibrous peel encases the lung. Thoracotomy may be necessary to free the entrapped lung.
          • If a patient has a persistent fluid collection with an adequately placed tube as evidenced by chest CT, intrapleural fibrinolytic therapy may be indicated. Intrapleural streptokinase, 250,000 units, is divided into three doses, each in 60 mL of normal saline. A dose is administered and flushed with 30 mL of normal saline. The tube is clamped and the patient rolled as described for pleurodesis; then the tube is returned to suction. The procedure is repeated every 8 hours. Alternatively, 250,000 units can be administered daily for 3 days. The adequacy of treatment is determined by resolution of the fluid collection and complete reexpansion of the lung.
          • A postpneumonectomy empyema is one of the most difficult complications to manage in thoracic surgery. Typically, there is a dehiscence of the bronchial stump and contamination of the pneumonectomy space with bronchial flora. The finding of air in the pneumonectomy space on chest x-ray is often diagnostic. The incidence of major bronchopleural fistula after pulmonary resection varies from 2% to 10% and has a high mortality (16% to 70%). Initial management includes thorough drainage (either open or closed) of the infected pleural space, antibiotics, and pulmonary toilet.
          • Definitive surgical repair of the fistula may include primary closure of a long bronchial stump or closure of the fistula using vascularized muscle or omental flaps. The residual pleural cavity can be obliterated by a muscle transposition, thoracoplasty, or delayed Clagett procedure.

            • Initially, a chest tube is inserted to evacuate the empyema. Great caution should be taken in inserting chest tubes into postpneumonectomy empyemas. A communicating bronchial stump–pleural fistula can contaminate the contralateral lung rapidly when decompression of the empyema is attempted. The patient should be positioned with the affected side down so that the remaining lung is not contaminated with empyema fluid. This procedure might best be handled in the operating room.
            • After the patient is stabilized, the next step usually is the creation of a Clagett window to provide a venue for daily packing and to maintain external drainage of the infected pleural space. This typically involves reopening the thoracotomy incision at its anterolateral end and resecting a short segment of two or three ribs to create generous access to the pleural space. The pleura is then treated with irrigation and débridement. After a suitable interval (weeks to months), the wound edges can be excised, and

the pneumonectomy space is closed either primarily or with a muscle flap after it has been filled with 0.25% neomycin solution. Alternatively, the space can be filled with vascularized muscle flap.
VIII. Chronic Obstructive Pulmonary Disease (COPD), Lung Volume Reduction, and Transplantation

  • The long-term consequences of smoking lead not only to lung cancer but also to COPD.

    • Destruction of lung parenchyma occurs in a nonuniform manner. As lung tissue loses its elastic recoil, the areas of destruction expand. This expansion of diseased areas, in combination with inflammation, leads to poor ventilation of relatively normal lung.
    • This leads to the typical findings of hyperexpanded lungs on chest x-ray: flattened diaphragms, widened intercostal spaces, and horizontal ribs. On pulmonary function testing, patients present with increased residual volumes and decreased FEV1.
    • Despite maximal medical and surgical treatment, the disease is progressive. Surgical treatment is generally reserved for the symptomatic (dyspnea) patient who has failed maximal medical treatment, with the goal of improving symptoms.
    • The goals of surgery are to remove diseased areas of lung and allow improved function of the remaining lung tissue.

  • The mainstays of surgical treatment have been bullectomy, lung volume reduction, and transplantation. Prior to any surgical intervention, patients must be carefully selected. Smoking cessation for at least 6 months is mandatory, as is enrollment in a supervised pulmonary rehabilitation program.

    • Bullectomy. Patients with emphysema may have large bullous disease. Emphysematous bullae are giant air sacs and may become secondarily infected.
    • Lung volume reduction may be indicated in patients who have predominantly apical disease, with FEV1 greater than 20% of predicted, and patients who may be too old for transplantation. Through a sternotomy incision, one or both lungs have areas of heavily diseased lung resected. Patients with diffuse emphysema are not candidates for this procedure.
    • Emphysema and α1-antitrypsin deficiency have become the leading indications for lung transplantation. Other common indications include cystic fibrosis, pulmonary fibrosis, and pulmonary hypertension.

      • Patients selected for lung transplantation generally are younger, have diffuse involvement of emphysema, and have FEV1 less than 20%.
      • Both single-lung and bilateral-lung transplantation have been performed for emphysema, although bilateral transplant patients have improved long-term survival.
      • The only absolute indication for bilateral lung transplantation is cystic fibrosis because single-lung transplantation would leave a chronically infected native lung in an immunocompromised patient.
      • Long-term, chronic allograft dysfunction in the form of bronchiolitis obliterans occurs in 50% of patients.

IX. Issues in the Care of the Thoracic Patient
A. Postoperative care of the thoracic surgery patient
Postoperative care of the thoracic surgery patient focuses on three factors: control of incisional pain, maintenance of pulmonary function, and monitoring of cardiovascular status.

  • The thoracotomy incision is one of the most painful and debilitating in surgery. Inadequate pain control contributes heavily to nearly all postoperative complications. Chest wall splinting contributes to atelectasis and poor pulmonary toilet. Pain increases sympathetic tone and myocardial oxygen demand, provoking arrhythmias and cardiac ischemic episodes. The routine use of epidural catheter anesthesia perioperatively and during the early recovery period has improved pain management significantly. Other effective analgesic maneuvers include intercostal blocks with long-acting local anesthetic before closure of the chest and

intrapleural administration or local anesthetic via catheters placed at the time of thoracotomy.

  • Maintenance of good bronchial hygiene is often the most difficult challenge facing the postthoracotomy patient. A lengthy smoking history, decreased ciliary function, chronic bronchitis, and significant postoperative pain all contribute to the ineffective clearance of pulmonary secretions. Even aggressive pulmonary toilet with incentive spirometry and chest physiotherapy delivered by the respiratory therapist, along with adequate analgesia, are insufficient on occasion. Diligent attention must be paid, including frequent physical examination and daily chest x-ray and arterial blood gas evaluation to detect any changes in gas exchange. Atelectasis and mucus plugging can lead to ventilation-perfusion mismatch and ensuing respiratory failure. The clinician should make liberal use of nasotracheal suctioning, bedside flexible bronchoscopy, and mechanical ventilatory support if needed.
  • All physicians caring for the postthoracotomy patient should be familiar with chest tube placement, maintenance, and removal. The purpose of chest tube placement after thoracotomy and lung resection is to allow drainage of air and fluid from the pleural space and to ensure reexpansion of the remaining lung parenchyma.

    • Chest-tube drainage is not used routinely with pneumonectomy unless bleeding or infection is present. Some surgeons place a chest tube on the operative side and remove it on postoperative day 1. Balanced pneumonectomy Pleurovacs have been advocated to balance the mediastinum during the first 24 to 48 hours. A chest tube in the patient with a pneumonectomy space should not be placed to conventional suction because of the risk of cardiac herniation.
    • Chest tubes are removed after the air leak has resolved and fluid drainage decreased (usually <100 mL over 8 hours). Chest tubes usually are removed one at a time. The patient is instructed to take a large inspiratory breath and hold it while the tube is removed swiftly and the site is simultaneously covered with an occlusive dressing. The technique of chest tube removal is critical to preventing air entry through the removal site.

  • Cardiovascular complications in the postoperative period are second in frequency only to pulmonary complications because the population that develops lung cancer is at high risk for heart disease. The three most common sources of cardiac morbidity are arrhythmias, myocardial infarctions, and congestive heart failure. A negative preoperative cardiac evaluation does not preclude the development of postoperative complications.
    • Cardiac arrhythmias occur in up to 30% of patients undergoing pulmonary surgery. The highest incidence occurs in elderly patients undergoing pneumonectomy or intrapericardial pulmonary artery ligation. All patients should have cardiac rhythm monitoring after thoracotomy for at least 72 hours.
    • A number of trials have failed to reach consensus on optimal regimen for prophylaxis.
    • Treatment of any rhythm disturbance begins with an assessment of the patient's hemodynamic status. Manifestations of these arrhythmias vary in acuity from hemodynamic collapse to palpitations. If the patient is hemodynamically unstable, the advanced cardiac life support protocol should be followed. After the patient has been examined and hemodynamic stability confirmed, an electrocardiogram, arterial blood gas sample, and serum electrolyte panel should be obtained. Frequently, supplementary oxygen and aggressive potassium and magnesium replenishment are the only treatment necessary. Premature ventricular contractions often are signs of myocardial ischemia. They should be treated expediently with electrolyte correction, optimization of oxygenation, and evaluation for ischemia.
    • Chest pain associated with myocardial infarction often goes unnoticed by caretakers and patients due to thoracotomy incisional pain and narcotic administration.
    • Perioperative fluid management of thoracic surgery patients differs from that of patients after abdominal surgery. Pulmonary surgery does not induce large fluid shifts. In addition, collapse and reexpansion of lungs during surgery can lead to pulmonary edema. Pulmonary edema should be treated with aggressive diuresis. This is largely due to the limited pulmonary reserve, most graphically demonstrated in the pneumonectomy patient in whom 100% of the cardiac output perfuses the remaining lung. Judicious fluid management, including avoiding fluid overload and pulmonary edema, is critical in patients with limited pulmonary reserve. Discussions regarding intraoperative fluid management should be held with the anesthesiologist before surgery. Physicians may need to accept transiently decreased urine output and increased serum creatinine. Mild hypotension may be treated with intravenous α-agonists such as phenylephrine. Cardiac dysfunction may also be the source of postoperative oliguria, pulmonary edema, and hypotension and should always be considered in patients who are not responding normally. Echocardiography or placement of a Swan-Ganz catheter may guide treatment.

X. Thoracoscopy
A. Diagnostic thoracoscopy
Diagnostic thoracoscopy (Surg Gynecol Obstet 1922;34:289)
  • Video-assisted thoracoscopic surgery (VATS) is performed in patients after thoracentesis and percutaneous pleural biopsy have failed to provide a diagnosis of suspected pleural disease. VATS frequently is used to diagnose malignancy in a solitary peripheral nodule. It is contraindicated in patients with extensive intrapleural adhesions or those who are unable to tolerate single-lung ventilation.
  • VATS is approximately 95% accurate for diagnosis of pleural disease.

B. Therapeutic thoracoscopy

  • VATS has been performed for peripheral lung biopsy, closure of leaking blebs, parietal pleurodesis, pericardiectomy, and excision of mediastinal cysts. Fewer lobectomies, pneumonectomies, and esophagectomies have been performed owing to concern about adequacy of complete tumor resection, and therefore they should be considered investigational procedures at this time.
    • Absolute contraindications include extensive intrapleural adhesions or the inability to tolerate single-lung anesthesia.
    • Relative contraindications include previous thoracotomy, tumor involvement of the hilar vessels, and previous chemotherapy or radiotherapy for lung or esophageal tumors.

  • The patient is placed in the lateral decubitus or semioblique position. Thoracoscopy requires selective intubation to allow collapse of the ipsilateral lung and to create a working space within the thorax (thus, insufflation gases are not needed). For most procedures, three incisions are required. The thoracoscope is placed through a port in the seventh or eighth intercostal space in the midaxillary line. Working ports for instruments generally are at the fourth or fifth intercostal space in the anterior axillary line and posteriorly near the border of the scapula. The endoscopic stapler, electrocautery, or laser can be used for resection. A chest tube is generally placed through one of the port sites.
  • Complications include hemorrhage, perforation of the diaphragm, air emboli, prolonged air leak, and tension pneumothorax.
  • Postoperative thoracoscopy management
    • A chest x-ray is taken and checked for residual air or fluid.
    • Chest tubes, if any, are usually removed in 1 to 2 days.
    • Analgesia is provided by patient-controlled anesthesia or orally administered medication as needed.
    • Diet is usually advanced by postoperative day 1.
    • Physical activity is as tolerated with a chest tube. Depending on the procedure and diagnosis, patients can return to work in approximately 1 week.

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