Pneumothorax	Choose Top of pageABSTRACTPneumothorax <<HemorrhageAir EmbolismTumor SeedingConclusionReferencesCITING ARTICLES

Pneumothorax is the most common complication of needle aspiration or biopsy of the lung, which is reported to occur in 17–26.6% of patients [1–4]. The chest tube insertion rate is much lower, ranging from 1% to 14.2% of patients [1–4].

A patient-related risk factor for pneumothorax is the presence of COPD. Fish et al. [5] found that the pneumothorax rate was 46% in patients with pulmonary function test and chest radiographs showing obstructive airway disease compared with 7% in patients with normal findings for both criteria. Another patient-related risk factor for pneumothorax is the lack of a history of ipsilateral surgery [1].

Certain lesion characteristics also predispose patients to pneumothorax. In cases in which the lesion is in the chest wall, mediastinum, pleura, or subpleural lung and no aerated lung is traversed by the biopsy needle, the likelihood of pneumothorax is minimal [4]. Increased depth of the lesion from the skin or long needle path (> 4 cm) is associated with an increased risk of pneumothorax [1, 2, 4]. Small lesion size also plays a role in the development of pneumothorax [1, 3].

Technical factors also affect the pneumothorax rate. The risk of pneumothorax increases with increased number of pleural punctures [6] and wider insertion angle of the needle—that is, when the needle is inserted less perpendicular to the pleura [2].

Many measures can be taken to help prevent the development of a pneumothorax and reduce the number of pneumothoraces requiring chest tube placement. Patients are instructed not to move, talk, cough, or breathe deeply during and immediately after the procedure. The use of a coaxial technique allows multiple specimens to be obtained with a single pleural puncture. To reduce the number of pleural punctures, interlobar fissures should be avoided. Careful planning is necessary to traverse the least amount of aerated lung without puncturing bullae or pneumatoceles if possible. Infusion of normal saline to expand the extrapleural space and displace the adjacent lung can be performed to avoid traversing aerated lung when biopsying a subpleural lesion [7]. A technique of obliterating, or “patching,” the needle track by injecting 2–3 mL of autologous blood during the final withdrawal of the introducer needle to minimize the incidence of postbiopsy pneumothorax may be considered in patients at high risk for developing pneumothorax [8]. Finally, after removal of the introducer needle after the biopsy, patients should immediately be positioned with the puncture site down [1, 6]. Oxygen is administered through a nasal cannula during and after the procedure to speed the resorption of the pneumothorax if one does develop [9].

If a pneumothorax develops during the procedure, it can be manually aspirated before the introducer needle is removed or by inserting a separate needle into the pleural space [10]. The needle is attached to tubing with a threeway stopcock and 50-mL syringe or is attached directly to a syringe, and aspiration of the air is performed as the needle is retracted and removed (Figs. 1A and 1B). Aspiration of the excess pleural air allows better apposition of the visceral and parietal pleura and prevents further enlargement of pneumothorax. Chest tube placement can frequently be avoided using this maneuver. However, as suggested by Yamagami et al. [10], when the amount of aspirated air is large (> 670 mL), chest tube placement should be considered.

Chest tube placement is indicated if a postbiopsy pneumothorax becomes symptomatic or continues to enlarge on chest radio graphs, usually obtained 1 and 3 hours after the procedure at our institution. Small-caliber, 6- to 9-French, catheters can be safely and easily placed under CT guidance (Figs. 2A, 2B, 2C, and 2D). The catheter can be attached to a one-way Heimlich valve, which allows the patient to remain ambulatory. Alternatively, the catheter can be attached to an underwater seal drainage device and wall suction. The chest tube can usually be removed 1–2 days after the procedure. However, in patients with preexisting pleural effusions, a larger catheter is usually required because the small catheters invariably become clogged with a clot or debris [9].

Hemorrhage	Choose Top of pageABSTRACTPneumothoraxHemorrhage <<Air EmbolismTumor SeedingConclusionReferencesCITING ARTICLES

Pulmonary hemorrhage is the second most common complication of needle biopsy of the chest, with reported frequencies ranging from 4% to 27% [3, 4]. The lower figure is based on the occurrence of hemoptysis, and the higher figure is based on the presence of postprocedural perilesional opacity. Hemothorax is exceedingly rare, with an incidence of 0.092% in one study [11]. Small lesion size and greater lesion depth or long biopsy path are associated with a higher risk of bleeding [3, 4]. Hemorrhage may also be related to CT evidence of emphysema, perhaps because of the lack of effective tamponade by adjacent tissue [12]. Patients with pulmonary arterial hypertension may also be at higher risk for hemorrhage [13].

Many measures can be taken to avoid life-threatening pulmonary hemorrhage or hemothorax. Percutaneous needle biopsy is contraindicated in patients who are taking an anticoagulant medication or who have a bleeding diathesis. Anticoagulants and antiplate-let medications should be withheld for the appropriate amount of time depending on the half-life of the medication. Although puncturing a pulmonary vessel should not lead to massive hemorrhage under normal physiologic conditions [13], one should, nevertheless, avoid major central vessels. Care must be taken to avoid systemic arteries including the subclavian, axillary, internal mammary, and intercostal arteries. When possible, the trajectory of the needle should aim away from the aorta and the heart to avoid inadvertent injury of these structures in the event of unexpected advancement of the needle.

View larger version (63K)

Fig. 1A—Aspiration of pneumothorax. (Courtesy of Loomis SL, Massachusetts General Hospital, Boston, MA) A, Syringe is attached to needle and air is aspirated as needle is withdrawn slowly.

View larger version (57K)

Fig. 1B—Aspiration of pneumothorax. (Courtesy of Loomis SL, Massachusetts General Hospital, Boston, MA) B, Complete aspiration of pneumothorax allows better apposition of visceral and parietal pleura.

When pulmonary hemorrhage manifests as a focal opacity on CT during the procedure, it is usually self-limited and the procedure should continue (Figs. 3A and 3B). However, if hemorrhage becomes clinically evident with cough and hemoptysis, the biopsy should be terminated. The patient should be placed in the decubitus position with the biopsy side dependent to prevent spillage of blood into the contralateral lung. Once the needle has been removed, the patient should be encouraged to cough up any blood clots that may obstruct an airway. In rare cases of massive hemorrhage, an emergent anesthesia consultation may be necessary to intubate the patient with a double-lumen endotracheal tube [9].

Air Embolism	Choose Top of pageABSTRACTPneumothoraxHemorrhageAir Embolism <<Tumor SeedingConclusionReferencesCITING ARTICLES

Air embolism is a rare but potentially fatal complication of percutaneous needle biopsy of the lung. In a large series of 9783 biopsies, there were only six cases (0.061%) of air embolism [11]. Several cases have been reported in the literature [14].

Air embolism is thought to occur by two mechanisms (Fig. 4). First, if the tip of the biopsy needle is lodged in a pulmonary vein and the inner stylet is removed, air embolism can occur during rapid inspiration when the atmospheric pressure exceeds the pulmonary venous pressure. Second, when a needle simultaneously traverses an air-containing space and adjacent pulmonary vein, a fistula can occur and air will enter the vein when the alveolar air pressure is greater than the pulmonary venous pressure—for example, with coughing. The risk of air embolism is thought to be increased with cystic or cavitary lesions, vasculitis, and positive pressure ventilation [14].

To prevent air embolism, the introducer needle should always be occluded by the inner stylet, saline drops, or a finger. The patient should be instructed to avoid breathing deeply and coughing during the biopsy. A cough suppressant may be given before the biopsy if necessary. Biopsy should be avoided if the patient has an intractable cough. In patients on mechanical ventilation, respiration should be suspended during needle manipulation. Patients should not undergo lung biopsy while in an upright or semiupright position [9, 14].

Air embolism usually manifests as fatal arrhythmias and circulatory collapse if the air enters the coronary arteries and results in coronary ischemia. Cerebral air embolism can lead to generalized seizures and neurologic deficits [9, 14].

If air embolism is recognized in the left heart or aorta during the procedure or is clinically suspected, the patient should be placed in the mild Trendelenburg position to prevent embolization of the air into the cerebral circulation; 100% oxygen should be administered immediately, which promotes the exchange of oxygen for nitrogen within the air bubbles and accelerates their resorption. Early hyperbaric oxygen therapy is recommended for patients with cerebral air embolism. Supportive therapy with an anticonvulsant medication or steroids may be administered as indicated for cerebral air embolism [9–14].

Tumor Seeding	Choose Top of pageABSTRACTPneumothoraxHemorrhageAir EmbolismTumor Seeding <<ConclusionReferencesCITING ARTICLES

Tumor seeding of the pleura or chest wall along the needle track is an extremely rare complication with a reported incidence of 0.012–0.061% [11, 15]. No definitive risk factor related to needle size, tumor size, or tumor location has been identified [15]. The reported incidence of needle track seeding from imaging-guided core needle biopsy specifically of pleural mesothelioma is 4%, higher than generally reported for transthoracic needle biopsy [16]. There are also a few case reports of needle track seeding after biopsy of thymoma. If the needle track metastasis is isolated to the chest wall without evidence of distant metastases, wide en bloc resection can be considered.

View larger version (200K)

Fig. 2A—Placement of chest tube was performed because pneumothorax developed in 68-year-old man who underwent biopsy of right lower lobe lung nodule. A and B, Chest radiographs obtained 1 hour (A) and 3 hours (B) after biopsy show enlarging pneumothorax. Arrows denote visceral pleural line.

View larger version (209K)

Fig. 2B—Placement of chest tube was performed because pneumothorax developed in 68-year-old man who underwent biopsy of right lower lobe lung nodule. A and B, Chest radiographs obtained 1 hour (A) and 3 hours (B) after biopsy show enlarging pneumothorax. Arrows denote visceral pleural line.

View larger version (183K)

Fig. 2C—Placement of chest tube was performed because pneumothorax developed in 68-year-old man who underwent biopsy of right lower lobe lung nodule. C, CT scan shows 7-French chest tube (arrow) placed by trocar method.

View larger version (169K)

Fig. 2D—Placement of chest tube was performed because pneumothorax developed in 68-year-old man who underwent biopsy of right lower lobe lung nodule. D, CT scan shows near complete resolution of pneumothorax after aspiration.

Conclusion	Choose Top of pageABSTRACTPneumothoraxHemorrhageAir EmbolismTumor SeedingConclusion <<ReferencesCITING ARTICLES

In summary, pneumothorax and pul monary hemorrhage are the most common complications of percutaneous needle biopsy of the chest. Air embolism and tumor seeding are extremely rare. Careful attention to biopsy planning and technique and postprocedural care help to prevent or minimize most potential complications.

View larger version (123K)

Fig. 3A—Postprocedural hemorrhage in 76-year-old man who underwent fine-needle aspiration of lung nodule. A, Axial CT image shows proper placement of introducer needle at edge of left upper lobe nodule.

View larger version (129K)

Fig. 3B—Postprocedural hemorrhage in 76-year-old man who underwent fine-needle aspiration of lung nodule. B, Obtained after fine-needle aspiration, CT image shows that consolidation and ground-glass opacities have developed posterior to nodule (arrow); these findings are consistent with hemorrhage. Patient had no symptoms and did not require any treatment.

View larger version (74K)

Fig. 4 —Proposed mechanisms of air embolism. If tip of biopsy needle is lodged in pulmonary vein (left) and inner stylet is removed, air embolism can occur during rapid inspiration when atmospheric pressure exceeds pulmonary venous pressure. If needle simultaneously traverses air-containing space (airway in this case) and adjacent pulmonary vein (right), fistula can occur and air will enter vein when alveolar air pressure is greater than pulmonary venous pressure—for example, with coughing. (Courtesy of Loomis SL, Massachusetts General Hospital, Boston, MA)