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Tubes & Lines. Radiographic Evaluation of the Placement of Monitoring and Support Devices. Tula Top. February 20, 2004. Central Venous Catheters. Central Venous Catheters. Purpose
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Tubes & Lines Radiographic Evaluation of the Placement of Monitoring and Support Devices Tula Top February 20, 2004
Central Venous Catheters Purpose Central venous catheters, also known as central venous pressure (CVP) lines, are used to monitor central venous pressure in the ICU and also allow for intravenous fluid or medication administration.
Central Venous Catheters Access and Placement CVP lines are typically inserted through the internal jugular,subclavian, or femoral veins, and offer more consistent venous blood flow than more peripherally inserted catheters, which may be subject to compression via vasoconstriction during times of cardiovascular collapse. The CVP line should ideally be positioned central to the venous valves at the origin of the superior vena cava. The SVC is formed by the junction of the right and left brachiocephalic veins and lies to the right of midline at the level of the first intercostal space. The following radiograph demonstrates a CVP line in the proper position.
Central Venous Catheters What’s the finding in the following chest radiograph?
The CVP line is in the left Subclavian Artery. Click for another hint.
We expect the line to end up here… The CVP line is in the left Subclavian Artery. Click for another hint.
We expect the line to end up here… The CVP line is in the left Subclavian Artery. Then, where is the tip located? Click for the answer.
Central Venous Catheters Answer: The tipis in Descending Thoracic Aorta. When the line extends above the clavicle, it is very likely that it lies in the subclavian artery. The subclavian vein normally lies behind the clavicle. Differential Location (if in vein): A left-sided SVC is a normal anatomic variant in 0.3% of individuals, of whom some two-thirds will also have a right-sided SVC. A large proportion of these individuals also will have the left BCV connecting to both the right and left SVCs. When the SVC is duplicated, the vessels typically are relatively smaller in caliber than those in patients with single SVCs. The left SVC drains through the oblique vein of the left atrium, the great cardiac vein, and the coronary sinus into the right atrium. Biffi M., et al. “Left superior vena cava persistence in patients undergoing pacemaker or cardioverter-defibrillator implantation: a 10-year experience.” Chest. 120(1):139-44, 2001 Jul.
Which Line Did you Put in?The Right or Left Subclavian? Right Subclavian Artery Left Subclavian Vein
Central Venous Catheters What’s the finding in the following chest radiograph?
Is the CVP line in the right place? Click for another hint.
Yes, it is. But what—and where—is this lucency? Is the CVP line in the right place? Click for the answer.
Central Venous Catheters Complications Air embolization is a potentially fatal complication of venipuncture and line placement and may be detected on CXR or CT with concomitant intravenous contrast injection.
Central Venous Catheters Complications Catheters placed in the left brachiocephalic vein should demonstrate an anterior curve on the lateral chest radiograph as the left BCV courses anteriorly to join the right BCV. A posterior projection of the catheter tip suggests placement into the azygos vein, which joins the SCV posteriorly prior to entering the pericardium. Such malpositioning may be missed if evaluated solely by a PA radiograph. Suspect placement of the catheter tip merits orthogonal views to confirm its location.
Central Venous Catheters Complications The vasculature in close proximity to the heart offers a number of aberrant routes for an inserted CVP line to follow. Among the most common are the: • Internal jugular vein • Right atrium (with risk of perforation or dysrhythmias if placed near the tricuspid valve) • Right ventricle • Opposite subclavian vein • Corresponding artery • Numerous extrathoracic locations (with potential of ectopically infusing toxic substances in the vicinity of the liver or heart instead of into the central venous system where rapid dilution can occur; look for widening and opacification of the mediastinum or pleural space due to rapid accumulation of fluid.) • Venous perforation may also occur if a catheter tip abutting the lateral wall of the SVC places excessive focal pressure on the wall.
Central Venous Catheters Complications • Every chest radiograph that features a CVP catheter should be evaluated carefully for pneumothorax, which occurs with 6% of line placements and can manifest several days after the procedure. Moreover, there is an increased potential for bilateral PTX given that a PTX on one side may have gone undetected following an initial failed attempt at line insertion before success was finally achieved on the other side. • Catheter embolization can occur as a result of laceration of the catheter by the insertion needle, catheter fracture at a point of stress, or detachment of the catheter from its hub. The freed apparatus may lodge in the SVC, inferior vena cava, right heart, or pulmonary artery, causing thrombosis, infection, or perforation.
Central Venous Catheters Complications • The catheter tip may serve as a nidus for clot formation, impairing its ability to measure central venous pressure accurately or to deliver fluids to the venous system. • Extension of the clot may result in venous thrombus or pulmonary embolus. • The “pinch-off” syndrome refers to impingement of the catheter between the clavicle and the first rib. This can result in fracture of the catheter or fragmentation.
Central Venous Catheters Summary of complications
Swan-Ganz Catheters Purpose Swan-Ganz (pulmonary artery flotation) catheters are placed to aid in the differentiation of cardiogenic from noncardiogenic pulmonary edema by allowing the clinician to monitor pulmonary capillary wedge pressure, reflecting left atrial pressure and left end-diastolic volume, via a central channel. Another channel allows assessment of central venous pressure and cardiac output. A third channel connects to an inflatable balloon at the catheter tip, which when inflated causes the tip to float distally through the arterial system and when deflated causes it to resume a more central position.
Swan-Ganz Catheters A Caveat Despite research indicating that radiographic findings allow a more accurate means of distinguishing between cardiogenic versus noncardiogenic edema, SG catheters are still in widespread use throughout all medical centers. Milne E.N., et al. “The radiologic distinction of cardiogenic and noncardiogenic edema.” American Journal of Roentgenology. 144(5):879-94, 1985 May.
Swan-Ganz Catheters Access and Placement Access is usually gained via the subclavian vein, but jugular and femoral vein approaches are also employed via use of a sheath called a cordis that facilitates advancement and withdrawal of the catheter and can provide short-term venous access once the SG is removed. The catheter tip is ideally positioned within the left pulmonary artery or the proximal interlobar artery. The following radiograph demonstrates a SG catheter in the proper position.
NGT Click to locate the ETT.
Tip of ETT NGT Click to locate the SGC.
Tip of ETT SGC NGT Click to proceed.
Swan-Ganz Catheters What’s the diagnosis in the following chest radiograph?
Is the SGT in the right place? Click for another hint.
No, in fact—it’s inserted too distally. And complicating things even more is this lucency, which is…? Is the SGT in the right place? Click for the answer.
Swan-Ganz Catheters Complications: Pulmonary infarction can also arise as a result of a persistently inflated balloon obstructing a major pulmonary artery. The inflated balloon appears as a 1-cm rounded radiolucency at the catheter tip. It should be inflated only when pressure measurements are being taken, and never while chest radiography is being performed. Dr. Gosselin will hunt you down if you do this!
Swan-Ganz Catheters What’s the finding in the following chest radiograph?
Complications Aberrant insertion of the SG catheter can also result in pulmonary artery rupture, pulmonary artery pseudoaneurysm, pulmonary artery to bronchial tree fistula, balloon rupture, and intracardiac knotting of the catheter. Other complications of SG catheters are similar to those that can occur with CVP lines. Also, redundancy or coiling of the SG catheter in the right heart can irritate the conduction bundle and induce dysrhythmias. Swan-Ganz Catheters
Swan-Ganz Catheters Complications The risk of pulmonary infarction increases the more distally the catheter tip is advanced, as the vessel diameters approach that diameter of the tip. Likewise, clot formation about the tip can lead to occlusion of the vessel in which it resides. Infarctions can be recognized on CXR by the appearance of patchy airspace opacification that is often wedge-shaped and subpleural in location.
Swan-Ganz Catheters Summary of Complications Complications associated with central venous pressure catheter placement Pulmonary infarction Distal placement of catheter tip Failure to deflate balloon Arrhythmia Catheter tip in right atrium or right ventricle Excessive coiling or redundancy of catheter tubing in right heart Pulmonary artery pseudoaneurysm Pulmonary artery rupture Pulmonary artery to bronchial tree fistula Intracardiac knotting of catheter Balloon rupture
Intra-Aortic Balloon Pumps Purpose The intra-aortic balloon pump consists of a long inflatable balloon 26-28cm in length surrounding the distal end of a centrally placed catheter. It is used in the setting of cardiogenic shock to enhance cardiac function.
Intra-Aortic Balloon Pumps Access and Placement The balloon pump is introduced via the femoral artery and advanced retrograde into the thoracic aorta. The balloon is ideally situated with the tip located just distal to the left subclavian artery at the level of the aortic arch. Such placement ensures maximal augmentation of diastolic pressures in the proximal aorta. Inflation of the balloon during diastole increases diastolic pressure, enhancing perfusion of the coronary arteries and oxygen delivery to the myocardium. Deflation of the balloon during systole creates a vacuum within the vessel lumen, decreasing ventricular afterload and enhancing forward blood flow. The following radiograph demonstrates an IABP in the proper position.
SGC Click to locate the IABP tip.
Tip of IABP SGC Click to locate the IABP proper.
Tip of IABP IABP SGC Click to proceed.
Intra-Aortic Balloon Pumps Complications • Even with ideal positioning, the long lumen of the IABP traverses the ostia of the celiac trunk, superior mesenteric artery, inferior mesenteric artery, and renal arteries and can lead to occlusion of these vessels (mesenteric ischemia, renal failure). • Too proximal a placement of the IABP can lead to obstruction of the left subclavian artery or cerebral embolus. • Too distal a placement of the IABP results in suboptimal counterpulsation during diastole. • Aortic dissection and death can rarely occur with advancement of the catheter during IABP placement. • Potential complications also include traumatic platelet and red blood cell destruction, peripheral emboli, balloon rupture with resultant gas embolus, and vascular insufficiency of the catheterized limb.
