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Drew A. Torigian, MD, MA, and Charles T. Lau, MD

Tubes, Lines, and CaTheTers

1. What is the radiographic appearance of an endotracheal tube (ETT), and where is it optimally placed?An ETT is usually detected by a thin, radiopaque line along its length, and its position should be determined relative to the carina, which if not seen on chest radiography can be approximated by following the course of the main stem bronchi medially at the T5-T7 level. The tip of the tube should be about 5 to 7 cm above the carina when the patient’s head is in neutral position and below the thoracic inlet because flexion and extension of the neck cause the tube to move about 2 cm higher and lower. The optimal width of the tube should be one half to two thirds of the tracheal width (generally <3 cm), and the inflated cuff should not distend the trachea because tracheal injury could occur.

2. Describe how an ETT may be malpositioned; list other potential complications of ETT placement.If the tube is inserted beyond the carina (i.e., with unilateral bronchial intubation), preferential hyperaeration and potential barotrauma of the intubated lung (more commonly the right) and hypoaeration and atelectasis of the contralateral lung may occur (Fig. 69-1). If the tube is not advanced far enough, inadvertent extubation or possible vocal cord damage because of pressure from the inflated cuff may occur. Esophageal intubation may also be encountered, which is detected clinically by gurgling sounds and distention of the stomach as air is insufflated and radiographically by lateral extension of the tube margins beyond the tracheal margins, visualization of the tracheal air column to the side of the tube, gastric distention, and lung hypoinflation. Other complications include:

• Pharyngeal, laryngeal, or tracheobronchial injury (particularly if placed too high or if the cuff is overinflated)• Aspiration• Sinusitis• Dislodgment of teeth

BA

A

Figure 69-1. A, Malpositioned ETT on frontal chest radiograph. Note tip of ETT within proximal right main stem bronchus (arrow ) with complete atelectasis (A) of the left lung. B, Repositioning of ETT on frontal chest radiograph. Note tip of ETT (arrow ) now appropriately positioned within the distal trachea with resolution of previously noted left lung atelectasis. Also note the normal course of the newly placed NGT (long arrows), which follows the expected course of the esophagus before entering the abdomen.

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3. What is the optimal positioning of a tracheostomy tube?A tracheostomy tube tip is optimally located one half to two thirds of the distance from the stoma to the carina. The tube itself should overlie the trachea, and the width of the tube should be about two thirds of the tracheal width.

4. Name potential complications after tracheostomy tube placement.• Injury of the recurrent laryngeal nerve with resultant vocal cord paralysis• Injury of the lung apex with pneumothorax or pneumomediastinum formation• Injury of the trachea with tracheal malacia or stricture formation• Soft tissue infection, leading to tracheal ulceration and perforation with tracheoinnominate artery fistula,

tracheoesophageal fistula, or cervical abscess formation

5. What is the radiographic appearance and ideal positioning of a nasogastric tube (NGT) or orogastric tube?Radiographically, a thin, radiopaque curvilinear strip is visualized along the entire length of the tube (Fig. 69-2). The tube should extend inferiorly along the midline of the chest, with its tip located at least 10 cm within the stomach because multiple side-holes are usually present from about 10 cm proximal to its distal end.

6. Describe the radiographic appearance and optimal location of an enteral feeding tube.On plain film radiography, a radiopaque marker at the tip of the tube is generally seen and should be located beyond the gastric pylorus within the duodenum, optimally at the duodenojejunal junction (ligament of Treitz). On frontal radiography, the tube generally curves to follow the C-shaped loop of the duodenum, and on lateral radiography, the tube curves posteriorly from the gastric antrum into the duodenum before it enters the retroperitoneal second portion of the duodenum (Fig. 69-3).

7. Discuss ways in which NGT, orogastric tube, or feeding tube may be malpositioned, including other potential complications.Coiling within the pharynx or esophagus may be seen even if the tip of the tube is in the appropriate position and may lead to vomiting and subsequent aspiration (Fig. 69-4). If a tube is located above the gastroesophageal junction, vomiting and subsequent aspiration may again occur. With tracheobronchial placement, the tube follows the course of the trachea and bronchi, sometimes with lung perforation and location within the pleural space, leading to intrabronchial infusion of feedings, pneumonia, lung abscess, empyema, hydropneumothorax, or pneumothorax (Fig. 69-5). Esophageal perforation is a rare, serious complication, but extraesophageal tube location is not generally appreciated on frontal radiography unless other views or water-soluble contrast agent injection are performed, which typically show a tube that does not follow the expected course of the esophagus, a widened mediastinum, pneumomediastinum, a unilateral pleural effusion, or contrast agent leak from the esophagus into other thoracic compartments.

8. If NGT, orogastric tube, or feeding tube is misplaced within the tracheobronchial tree, what should one do before removing the tube?One should have a thoracostomy tube set ready at the patient’s bedside before removing the tube, just in case a pneumothorax suddenly develops because of lung perforation with a tear in the visceral pleura.

9. When is a thoracostomy tube generally used?A thoracostomy tube is generally placed for drainage of air (pneumothorax), particularly when persistent (i.e., with a bronchopleural fistula), large, increasing, or symptomatic (i.e., under tension); fluid (pleural effusion); blood (hemothorax); chylous fluid (chylothorax); or pus (empyema) from the pleural space. It may also be placed for drainage of a lung abscess.

Figure 69-2. Appropriately positioned NGT on frontal radiograph. Note the thin radiopaque curvilinear strip along entire length of NGT (arrows), which extends inferiorly along the midline of the chest in the expected location of the esophagus with the tip overlying the expected location of the stomach.

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10. What is the radiographic appearance of a thoracostomy tube, and where should its tip be located?A curvilinear radiopaque stripe that has a short-segment interruption in it at the level of its proximal drainage hole is typically seen on radiography; the tube should curve gently within the thorax (Fig. 69-6). For drainage of a pneumothorax, the tube should be positioned near the lung apex at the anterior axillary line and directed anterosuperiorly, whereas for drainage of a pleural effusion, the tube should be positioned at the mid-axillary line and directed posteroinferiorly through the sixth through eighth intercostal spaces. In either case, the proximal side-hole should always be located medial to the ribs within the pleural space. Computed tomography (CT) is indicated when a thoracostomy tube does not drain air or fluid properly, and the chest radiograph is noncontributory.

11. Discuss potential complications of thoracostomy tube placement.Persistent pneumothorax and extensive subcutaneous emphysema may occur if side-holes are located external to the rib cage and pleural space (Fig. 69-7). Lung laceration with bronchopleural fistula may also occur (Fig. 69-8) with a persistent pneumothorax, pneumomediastinum, and extensive subcutaneous emphysema and is more commonly seen with preexisting lung disease or pleural adhesions. Laceration or injury of an intercostal artery, phrenic nerve, thoracic duct, diaphragm, liver, spleen, stomach, mediastinum, heart, breast, or pectoralis muscle may also occur. Placement within an interlobar fissure is common, may cause poor tube function, and is best seen on CT. Soft tissue or pleural infection may occur adjacent to the tube insertion site. Unilateral re-expansion pulmonary edema may be seen with rapid pleural decompression, and rapid development of an infiltrate at the tip or side-holes may be due to pulmonary infarction from suction of lung tissue. High insertion in the posterior chest wall may lead to Horner syndrome, and recurrence of a pleural collection, pleurocutaneous fistula, or retention of a tube fragment are potential complications after tube removal.

Figure 69-3. Appropriately positioned feeding tube on frontal abdominal radiograph. Note feeding tube (short arrows) that curves to follow the C-shaped loop of duodenum with radiopaque marker at the tip overlying the expected located of the duodenojejunal junction (ligament of Treitz). Also note appropriately positioned tip of NGT (long arrow) overlying the expected location of the stomach in the left upper quadrant of the abdomen with a thin radiopaque curvilinear strip along its visualized portion.

Figure 69-4. Malpositioned feeding tube on frontal chest radiograph. Note portion of feeding tube (arrows) curled within the pharynx and upper thoracic esophagus.

Figure 69-5. Malpositioned feeding tube on frontal chest radiograph. Note feeding tube (short arrows) following course of right bronchi and terminating in inferior right hemithorax within pleural space. Also note right thoracostomy tube (long arrows) within right pleural space to drain complex pleural fluid.

tubes, lines, and catheters 489thoracic radiology

12. How can I decrease the chance of injury to an intercostal artery or vein during thoracostomy tube placement? Place the tube just superior to a rib to avoid the neurovascular bundle that is located at the inferior aspect of each rib.

13. Describe the basic normal venous anatomy of the chest.The deeply situated brachial veins and the superficially situated basilic and cephalic veins of the upper extremities converge centrally to form the axillary veins. The axillary veins become the subclavian veins beyond the lateral aspects of the first ribs, and the superficially located external jugular veins drain from the neck into the subclavian veins. More centrally, the subclavian veins and internal jugular veins from the neck converge to form the brachiocephalic veins (longer

on the left than on the right), which join to form the superior vena cava (SVC), finally leading to the right atrium. The vertical portion of the azygos vein is located to the right of the thoracic spine and drains superiorly to its horizontal portion, which drains into the posterior SVC above the right main stem bronchus. The hemiazygos venous system is located toward the left of the thoracic spine and has variable communication with the azygos system.

14. What is the radiographic appearance and optimal location of a central venous line (CVL) and a peripherally inserted central catheter (PICC)?A CVL appears as a thin, moderately radiopaque linear or curvilinear tube that extends centrally from a subclavian or internal jugular vein when in the chest (Fig. 69-9), whereas a PICC appears as an even thinner, faintly radiopaque linear or curvilinear tube that extends from the upper extremity (because it is placed peripherally within the lower arm or upper forearm usually via the basilic vein) centrally into the chest. The optimal location of the tip of a CVL and PICC is within the SVC.

15. What are potential complications of CVL or PICC placement?Early complications include pneumothorax, which is very common and more commonly encountered in the subclavian approach; malpositioning within a vein or artery or in the heart; arterial injury with pseudoaneurysm formation or thromboembolism; venous injury; perforation through a vein with extravascular malpositioning in the pleural space,

Figure 69-6. Appropriately positioned thoracostomy tube for pneumothorax on frontal chest radiograph. Note gentle curve of the thoracostomy tube (short arrows) with curvilinear radiopaque stripe and short-segment interruption because of side-hole (long arrow ) with the tip located near the lung apex directed anterosuperiorly.

Figure 69-7. Malpositioned thoracostomy tube on frontal chest radiograph. Note thoracostomy tube (short arrow ) with side-hole (long arrow ) located external to rib cage.

Figure 69-8. Malpositioned thoracostomy tube on CT. Note thoracostomy tube (arrow ) located within right lung parenchyma instead of pleural space.

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mediastinum, or soft tissue; cardiac injury with risk of myocardial perforation and cardiac tamponade; hemorrhage or hematoma; air embolism; and catheter knotting, fracture, and embolism. Late complications include catheter occlusion, migration, knotting, fracture, and embolism; venous thrombosis; soft tissue infection; bacteremia/septicemia; and cardiac dysrhythmias, which usually occur with low right atrial placement.

16. List locations where a CVL or PICC may be malpositioned when inserted through a vein.For a PICC or subclavian vein CVL, malpositioning may occur in the ipsilateral internal jugular vein (Fig. 69-10); contralateral subclavian vein; internal jugular vein; right atrium; right ventricle; pulmonary artery; inferior vena cava; hepatic vein; axillary vein; subclavian vein; brachiocephalic vein; azygos vein; or branch vessels, including the external jugular vein, inferior thyroidal vein, superior intercostal vein, internal thoracic vein, or pericardiacophrenic vein. For an internal jugular vein CVL, malpositioning within the ipsilateral subclavian vein may also occur. Intracardiac malpositioning of a CVL inserted via the subclavian vein approach is more common when inserted on the right (30%) than on the left (12%).

17. Name some clues of inadvertent arterial puncture with CVL, PICC, or Swan-Ganz catheter (SGC).At the time of catheter placement, bright red and pulsatile backflow of blood may be seen, although in patients with hypoxia or hypotension, the blood may be nonpulsatile and dark, mimicking venous blood. On chest radiography, arterial location of a catheter should be suspected when the course of the catheter follows the expected course of an artery rather than a vein, or when the tip is located in a mid-sternal or left paravertebral location. Confirmation of an arterial puncture may be performed by analysis of blood gas levels of blood samples drawn through the catheter.

18. What should one consider in the differential diagnosis for rapid development of an ipsilateral pleural effusion or mediastinal widening after CVL, PICC, or SGC placement?Rapid development of an ipsilateral pleural effusion or mediastinal widening after venous catheter placement should make one consider (1) perforation of a vein by the catheter, with the tip located in the pleural space or mediastinum after catheter infusion, or (2) vessel injury by the catheter with associated hemithorax or mediastinal hematoma. Pneumothorax is also often associated with vessel injury in this setting.

19. If air embolism is suspected during catheter placement, what should one do to treat the patient?When air embolism is suspected (usually when a sucking sound during patient inspiration is heard through a catheter at the time of placement or if inadvertent injection of air through a catheter occurs), the patient should immediately be placed in the left lateral decubitus position (i.e., left side down) to keep the air trapped in the right heart chambers, supplemental oxygen should be administered, and vital signs should be monitored.

20. How do I prevent air embolism during catheter placement in the first place?Air embolism during line placement is easily prevented by keeping a finger over the open end of the catheter until the catheter is flushed with saline and capped.

M

M

Figure 69-9. Appropriately positioned chemoport CVL for history of uterine sarcoma on frontal chest radiograph. Note thin, moderately radiopaque curvilinear tube (arrows) that overlies right internal jugular vein with tip overlying SVC. Also note multiple pulmonary nodules and masses (M ) in lungs because of metastases.

Figure 69-10. Malpositioned PICC on frontal chest radiograph. Note right PICC (arrows) seen as thin radiopaque curvilinear tube extending from right upper extremity into the right neck overlying the expected location of the right internal jugular vein.

tubes, lines, and catheters 491thoracic radiology

21. Describe the radiographic appearance of SGC and its optimal location.SGC (or pulmonary arterial catheter) appears as a thin, moderately radiopaque curvilinear tube that originates centrally from a subclavian or internal jugular vein and passes successively through the brachiocephalic vein, SVC, right atrium, right ventricle, and pulmonary outflow tract, with its tip optimally located in the main, right, or left pulmonary artery or within a proximal lobar pulmonary arterial branch (Fig. 69-11). When a balloon at the tip is inflated for pulmonary capillary wedge pressure measurement, a 1-cm round radiolucency at the catheter tip may be seen radiographically. A thin, short linear tubular radiopacity is also generally seen at the skin entry site, which is the vascular sheath that surrounds the SGC. The SGC can be removed while the sheath still remains in place.

22. What are potential complications of SGC placement?Potential complications of SGC placement include the complications listed previously for CVL or PICC placement and malpositioning within the right atrium, right ventricle, pulmonary outflow tract, or peripheral pulmonary arterial branch; curling within cardiac chambers (Fig. 69-12) with associated cardiac injury, thrombus formation, or atrial or ventricular cardiac dysrhythmias; tricuspid or pulmonic valve injury; pulmonary arterial injury/rupture, occasionally with formation of either a pseudoaneurysm or a pulmonary artery to bronchial fistula; pulmonary thromboembolism; and pulmonary infarction.

23. Why can pulmonary infarction occur as a complication of SGC placement?Pulmonary infarction with SGC placement results from obstruction of pulmonary blood flow because of tip placement too peripherally within a pulmonary arterial branch or persistent inflation of the balloon at the catheter tip. Generally, the extent of pulmonary infarction is directly related to the caliber of the occluded vessel and to the portions of lung supplied by it. Typically, if the tip of the SGC is seen to be more than 2 cm lateral to the pulmonary hilum on frontal chest radiography, it is too peripheral in location and should be pulled back. The balloon should be inflated only during the measurement of wedge pressures.

24. How does an intra-aortic counterpulsation balloon (IACB) work?An IACB is inserted percutaneously via the common femoral artery and subsequently passes through the external iliac artery, common iliac artery, and abdominal aorta to reach the descending thoracic aorta. A long, inflatable balloon approximately 3 cm long is present around the distal catheter that is repeatedly inflated during early diastole and deflated during early systole at each cardiac cycle. This helps to increase myocardial oxygenation and decrease myocardial oxygenation demand, mainly through improved coronary and peripheral arterial blood flow and decreased cardiac afterload.

Figure 69-12. Malpositioned SGC on frontal chest radiograph. Note SGC (arrows) curled over right heart with tip overlying the superior aspect of the right atrium.

Figure 69-11. Appropriately positioned SGC on frontal chest radiograph. Note thin, moderately radiopaque curvilinear tube (short arrows) that overlies right internal jugular vein in the neck and successively follows the course of the right brachiocephalic vein, SVC, right atrium, right ventricle, and pulmonary outflow tract, with the tip located over the main pulmonary artery. Also note the appropriately positioned tip of NGT overlying the stomach in the left upper quadrant of the abdomen (long arrow ).

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25. What are the major indications and contraindications for placement of IACB?IACB is often used in critically ill patients with left ventricular failure, unstable angina, acute myocardial ischemia/infarction associated with percutaneous transluminal angioplasty, or severe mitral regurgitation. Major contraindications to IACB placement include severe aortic insufficiency, aortic dissection, severe peripheral vascular disease, or contraindication to systemic anticoagulation.

26. Describe the radiographic appearance of an IACB and its optimal position.The distal tip of an IACB is seen as a small, radiopaque rectangle and should be located on frontal chest radiography just distal to the left subclavian artery within the proximal descending thoracic aorta below the level of the aortic knob (Fig. 69-13).

27. What are the potential complications of IACB?Potential complications include arterial injury and hemorrhage; aortic dissection; arterial thromboembolism with secondary limb, visceral, or cerebral ischemia; malpositioning within the aorta proximal to the left subclavian artery or far distal to the aortic arch; venous malpositioning; balloon rupture with potential air embolism if helium gas is used for balloon inflation; thrombocytopenia; soft tissue infection or hematoma formation at the percutaneous site of insertion; or bacteremia/septicemia. When the balloon is located proximal to the left subclavian artery, potential occlusion of the arterial branch vessels of the aortic arch (i.e., innominate, left common carotid, and left subclavian arteries) is possible; when the balloon is located far distal to the aortic arch, counterpulsation is less effective, and potential occlusion of the visceral branch vessels is possible.

28. What is the radiographic appearance of a transvenous pacemaker or automatic implantable cardioverter defibrillator (AICD)?The power/generator pack for a transvenous pacemaker or AICD is located subcutaneously in the pectoral area of the anterior chest wall and appears as a radiopaque, round or ovoid structure that is about 5 cm in diameter on frontal chest radiography. The metallic lead appears as a dense, thin curvilinear radiopacity (associated with thicker short segments of spring defibrillation coils in the case of AICD) that generally extends through the subclavian or internal jugular vein from the generator pack to pass through the brachiocephalic vein and SVC, subsequently terminating in the right atrium, right ventricle, or coronary sinus (Figs. 69-14 and 69-15A).

29. Where should the leads of a transvenous pacemaker or AICD be located?A right atrial lead (usually in the right atrial appendage) curves around the right side of the heart on frontal chest radiography just below the SVC. On frontal chest radiography, a right ventricular lead should project slightly to the left of midline over the ventricular apex, and on lateral chest radiography it should project anteriorly and inferiorly near the ventricular apex. A lead within the coronary sinus projects superiorly and to the left over the heart on frontal chest radiography, and on lateral chest radiography it is directed posteriorly along the course of the atrioventricular groove.

Figure 69-13. Appropriately positioned IACB on frontal chest radiograph. Note linear radiopaque IACB (arrows) overlying descending thoracic aorta to the left of midline with small radiopaque rectangle at the tip overlying proximal descending thoracic aorta inferior to the aortic knob.

Key Points: Tubes, Lines, and Catheters

1. If NGT, orogastric tube, or feeding tube is seen to extend into a distal bronchus, lung, or pleural space, the clinical staff should be notified immediately, and the radiologist should suggest that tube removal be performed only after a thoracostomy tube set is at the bedside in case a significant pneumothorax develops.

2. Rapid development of an ipsilateral pleural effusion or mediastinal widening after venous catheter placement should lead one to consider venous perforation, with the tip located in the pleural space or mediastinum after catheter infusion, or vessel injury with associated hemithorax or mediastinal hematoma.

3. When air embolism is suspected during line placement or use, the patient should immediately be placed in the left lateral position to keep the air trapped in the right heart chambers, supplemental oxygen should be administered, and vital signs should be monitored.

tubes, lines, and catheters 493thoracic radiology

A

P

P

B

Figure 69-14. A, Appropriately positioned AICD on frontal chest radiograph. Note power/generator pack (P ) over left pectoral area as radiopaque ovoid structure connected to a thin curvilinear metallic lead (short arrow) with the tip overlying the right ventricular apex to the left of midline. Also note the thicker, short segments of spring defibrillation coils (long arrow). B, Appropriately positioned AICD on lateral chest radiograph. Note power/generator pack (P) over anterior chest wall connected to thin curvilinear metallic lead (short arrows) with tip overlying the right ventricular apex anteriorly and inferiorly. Also note thicker, short segments of spring defibrillation coils (long arrows).

A

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Figure 69-15. A, Appropriately positioned transvenous pacemaker on frontal chest radiograph. Note power/generator pack (P ) over left pectoral area as a radiopaque ovoid structure connected to leads with tip in the right atrium (short arrow ) overlying the right side of the heart and tip in the right ventricle (long arrow) overlying the ventricular apex. B, Subsequent dislodgment of right atrial lead of transvenous pacemaker with migration to the right ventricle on frontal chest radiograph. Note new position of right atrial lead (short arrow) compared with A, similar to right ventricular lead (long arrow).

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30. What are potential complications of transvenous pacemaker/AICD placement?Potential complications of transvenous pacemaker/AICD placement include all the complications of SGC, CVL, and PICC placement previously listed and hematoma or abscess formation around the generator pack; lead malpositioning, redundancy, tautness, dislodgment (Fig. 69-15B), migration, or fracture with or without embolism (Fig. 69-16); twiddler’s syndrome; cardiac perforation; loss of pacing or cardioversion/defibrillation function; and induction of cardiac dysrhythmias. Cardiac perforation by a lead should be suspected on chest radiography (particularly on the lateral view) if the lead extends beyond the margin of the cardiac silhouette.

31. What is twiddler’s syndrome?Twiddler’s syndrome is a rare disorder in which a patient causes malfunction of a transvenous pacemaker or AICD by manipulating or “twiddling” with the pacing generator pack, which may be facilitated by a large pocket for the generator pack or loose subcutaneous tissue, leading to dislodgment of the pacing leads. Chest radiography is the key to diagnosis and typically shows twisting or coiling of the lead around the axis of the pacemaker and possible lead fracture, displacement, or migration.

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Figure 69-16. Fracture of pacemaker lead on frontal chest radiograph. Note discontinuity (arrow) of one pacemaker lead.