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Introduction
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Suppose you just placed the central line shown above. Does it need to be repositioned?
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I was trained that the tip of the central line must lie in the lower portion of the superior vena cava. If the line was in the right atrium, it would cause cardiac perforation. If the line was too high, then vasopressors would sclerose the vein. At that time we were very interested in mixed venous oxygen saturation and central venous pressure, further mandating placement in the superior vena cava. With newer evidence and changes in our management of sepsis, how should we position central lines now?
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What is the ideal placement of a central line?
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The right atrium is fine
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Traditionally atrial placement was feared due to possible risk of cardiac perforation. However, this problem seems limited to older, stiffer central lines. A review concluded that the risk of cardiac perforation from a catheter in the right atrium is currently an “urban legend” (Pittiruti 2015). Hemodialysis catheters achieve better flow rates in the right atrium, so some nephrology guidelines recommend intentional placement in the atrium. Catheter placement within the right atrium does not appear to increase arrhythmia significantly (Vesely 2003; Torres-Millan 2010).
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The superior vena cava, brachiocephalic veins, and subclavian veins seem OK
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Traditional teaching was that infusion of vasopressors at these sites could cause vascular damage. However, we are now comfortable infusing vasopressors through peripheral veins as well as through midline catheters (which often terminate in the subclavian vein). Thus any large vein is probably fine for vasopressors.
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Observational studies correlate lines placed more peripherally with increased thrombosis among oncology patients receiving permanent indwelling ports for chemotherapy. However, these studies are not applicable to short-term non-tunneled catheters placed in critically ill patients. For example, outpatients are much more active than ICU patients and this could lead to repetitive irritation of the vein.
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It is commonly feared that a left-sided central line with its tip riding against the superior vena cava (as shown above) could eventually puncture the vessel. However, as with cardiac perforation, there is little evidence to support this with modern catheters. Superior vena cava perforation is indeed a complication of central line placement, but these rare events seem to occur during line placement (e.g. due to forcing deep passage of the dilator). Modern case reports describe this as occurring immediately or within 24 hours of catheter insertion, reflecting procedural injury rather than delayed injury from the catheter itself (1). Thus, repositioning a catheter away from the wall of the superior vena cava may be unnecessary.
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Comparison with femoral lines
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Malposition of femoral central venous catheters is virtually unheard of. Why? Because we don't check them. If we routinely obtained an X-ray after every femoral catheter, we would discover that these lines are not always where we intended (for example, one report suggested that 4.5% lie in the lumbar vein; Gocaze 2012). Nonetheless, nothing bad seems to happen (although a hemodialysis catheter in the lumbar vein won't work). Overall this supports the concept that the exact location of central lines may not matter.
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Bottom line on ideal line location?
“There are no conclusive studies on optimal catheter tip positioning.”
– Frykholm et al.Clinical Guidelines on Central Venous Catheterization 2014
There is no clear evidence what the best position is. Although “malpositioning” of central lines is common, this is well tolerated (Pikwer 2008). These lines are placed for a short period of time and usually aren’t used for anything tremendously irritating (i.e. hydrochloric acid, chemotherapy). Line placement in the right atrium, superior vena cava, brachiocephalic veins, and subclavian veins occurs frequently and seems to be safe. There is less evidence to support the safety of lines aberrantly placed in the internal jugular pointing upwards towards the head (example below), so my practice is to avoid this.
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Tolerating unorthodox line position has certain advantages
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Less repositioning or replacement of central lines
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Placing a new central line exposes the patient to all of the risks of central line placement. Repositioning a line is preferable, but unnecessary manipulation of the line could increase the risk of infection. Both maneuvers cause patient discomfort, consume time, and often lead to repeated X-rays.
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Line confirmation solely via ultrasonography
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If we can accept a line tip position anywhere from the subclavian vein to the right atrium, this facilitates replacement of the post-procedure X-ray with ultrasonography.
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Ultrasonographic approach to verifying central line placement
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- [a] Rule out pneumothorax with lung ultrasound.
- [b] Examine the internal jugular veins with ultrasonography (excluding the site of catheter placement, if it was placed in one). This should exclude a misdirected catheter pointing upwards into the head (as shown below; Zanobetti 2013).
- [c] Inject a saline flush into the distal port of the catheter while visualizing the right atrium on echocardiography. Appearance of bubbles within the right atrium proves that the catheter is either within the atrium or the venous system. Although agitation of the saline using a three-way stopcock may produce more bubbles, a regular saline flush is easier and produces sufficient bubbles (Gekle 2015).
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Appearance of microbubbles in the heart more than 2 seconds after injection of agitated saline suggests a distal location of the catheter (e.g. within the subclavian vein; Duran-Gehring 2014). This ought to be OK as long as catheter malposition within the internal jugular vein is excluded. An X-ray should be considered however.
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Ultrasonography has important advantages compared to chest X-ray:
- Ultrasonography is faster, allowing immediate use of the catheter in emergent situations.
- Ultrasonography has been proven to have superiorperformance for the detection of pneumothorax, perhaps the most important post-procedural complication.
- Chest X-ray will be fooled by rare anatomic variants (e.g. persistent left superior vena cava), which may cause the line to look like it is overlying the lung or aorta. In these situations, the saline flush test will correctly indicate that the line is within the venous system (Prekker 2010).
- Chest X-ray may be fooled by improperly placed lines which are nonetheless overlying the superior vena cava and thus appear to be correctly placed on a portable radiograph (e.g. this case by ScanCrit blog). In these situations, the saline flush test should to reveal that the line is not in the venous system.
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Overall ultrasonography is probably superior to X-ray at rapidly and definitively answering the two relevant clinical questions (Is there a pneumothorax? Is the catheter in a intrathoracic vein?).
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Currently it remains the norm to obtain a post-procedure X-ray. Eventually this practice may be abandoned, as was the practice of obtaining mandatory daily chest X-rays in every intubated patient. This could save ~500 million dollars every year in the USA (2).
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- The ideal placement of the central line tip is unknown.
- Placement of central lines within the right atrium appears safe, and is specifically recommended by some guidelines for hemodialysis catheters.
- Central lines terminating in the brachiocephalic trunk or subclavian vein are probably fine to use for most critical care applications (other than, for example, measurement of central venous pressure or mixed venous oxygen saturation).
- A combination of lung ultrasonography, internal jugular vein ultrasonography, and cardiac ultrasonography with a microbubble injection usually allows immediate exclusion of pneumothorax and proof that the catheter is in a intrathoracic vein. Ultrasonography may be superior to chest X-ray for confirmation of line placement.
[PLEASE NOTE: This post has been updated slightly with a short new post adding some details and newer information. The material here is still correct, so start with this post.]
Notes
[1] For example, see case reports by: Funkai 2006, Maroun 2013, Kabutey 2013, Turi 2013, Kim 2010, Tilak 2004, Wang 2009, and Azizzadeh 2007. There are a few case reports of delayed perforation of the superior vena cava among cancer patients receiving chemotherapy, which might relate to the vesicant properties of the chemotherapy.
[2] It is estimated that 3 million central lines are placed annually in the United States, with a chest radiograph costing almost $200. This figure doesn't take into account the number of dollars wasted repositioning or replacing central lines that are probably fine to begin with.
More information
- Bubble test by Mount Sinai Emergency Medicine Ultrasound
- Saul et al. The ultrasound-only central venous catheter placement and confirmation procedure. J Ultrasound Med 2015; 34: 1301-1306.
Image credits: Torso image from https://en.wiktionary.org/wiki/torso
Josh is the creator of PulmCrit.org. He is an associate professor of Pulmonary and Critical Care Medicine at the University of Vermont.
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Great post. Very interesante.
To avoid misplacement of the central line we used the very simple technic discribed by Bedel et al http://www.ncbi.nlm.nih.gov/pubmed/24052186
Subclavian view show intracardiac positionning of the guidewire before insertion of the catheter. We believe this to be a better approch for your [b] point.
Elegant technique, thanks for sharing.
It might be difficult to implement this technique for 100% of central line procedures, because it requires two operators. Also, for some truly emergent procedures, real-time wire visualization in the heart might slow things down a bit.
However, this technique does have a major advantage of allowing repositioning of the wire and/or catheter during the procedure. Thus, in situations where it is feasible, I agree that it may be superior to [b] above.
What about catheter kink or coiling upwards. Still you can aspirated blood from all lumens!!!
In situations where I’ve had kinked catheters, there was always something funny about the procedure that alerted us to the possibility of misplacement (e.g. difficulty threading catheter, difficulty flushing catheter, etc.).
Do we place central lines for the benefit of patients or practitioners? This approach is not patient centric, and more thorough research would have revealed the hazards of incorrect tip position. There have been multi-million dollar awards for subclavian placement. Survey risk managers on IV injury payouts related to your approach. The payouts are astonishing. Look at how many law practices specialize in IV injury. Multitudes of peer reviewed articles advocating for low SVC placement, primarily due to high complication rate. NKF, SIR, CDC,FDA, SHEA, ONS,INS, AVA all disagree with the conclusions in this article.
Stephen Harris
Having a CVC in the subclavian vein isn’t necessarily awesome, the question is what is the risk/benefit of using it versus repositioning it or replacing the line. Clinical experience with midline catheters argues strongly that infusions of most solutions into the subclavian vein is fine (probably not chemotherapy or TPN). If x-ray confirmation were really necessary, anesthesiologists would be killing patients all the time by placing central lines in the OR before long cases and not checking position with an X-ray. I reviewed several guidelines while working on the post. Many do recommend placement in the SVC, on the basis… Read more »
Appreciate your points but will repeat some of mine. Multiple journal articles that clearly demonstrate CVC with tip positions out of the CAJ/Low SVC area have higher rates of thrombosis, infection and catheter malfunction. I didn’t mention frivolous lawsuits, I mentioned multi-million dollar award lawsuits(which happened to have severe pt. injury). Of course these don’t guide clinical practice, but your original blog point suggested that it is “probably ok” to practice outside guidelines from multiple organizations. I thought it might be helpful to know some of the hazards of doing so. There are multitudes of commonly administered drugs besides TPN… Read more »
Please provide citation to original primary journal articles to which you are referring (not review articles or consensus articles, but rather primary original research articles containing actual data). I am not aware that there are “Multiple journal articles that clearly demonstrate CVC with tip positions out of the CAJ/Low SVC area have higher rates of thrombosis, infection and catheter malfunction” – what are the references? Keep in mind that this is a post about non-tunneled, temporary central venous catheters. Therefore, evidence regarding PICC lines, or especially implanted ports (which typically stay in place much longer and in active out-patients) is… Read more »
Josh, we elaborated on your post on central venous catheters and showed that medical residents can learn and apply the “rapid atrial swirl sign” pretty quickly. Maybe you’re interested in our experience which supports that chest x-rays are not always needed.
http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0199345
Best regards,
Peter
What about if it goes in the azygous but still enters into the RA?
The azygous vein doesn’t terminate in the RA. A catheter traveling through the SVC with the tip entering the azygous vein is then traveling toward the spine; not the RA.