A few days ago, I received a question about confirming tip location of a newly inserted CVAD when the patient is located in the OR for insertion. As stated in many standards and guidelines documents, some method to confirm correct tip location is necessary before infusion begins through any CVAD. Historically, the most common method for this tip confirmation is by obtaining a chest xray.
From the question I received, it would appear that obtaining a chest xray in the OR after a CVAD insertion is not common practice by surgeons and anesthesiologist. I can understand that adherence to the OR schedule is a significant issue and that time to obtain and interpret a chest xray may not be factored into that schedule. I have also heard discussions of insertion sites and malpositioned CVADs with some thinking that the internal jugular site has virtually no chance for malposition on insertion while others insertion sites have a greater risk. Many report that a chest xray is performed after the patient has been transferred to PACU or ICU, however this is after the catheter has been used for fluid and medication infusion during the surgical procedure. In my opinion, this sounds like a double standard – one for the OR and a different one for other patient care areas.
While I cannot quote any data on what is the most common practice regarding this issue, I can point to the most recent set of guidelines from the American Society of Anesthesiologists. Click the title to gain free access to download
Practice Guidelines for Central Venous Access: A Report by the American Society of Anesthesiologists Task Force on Central Venous Access was published in 2012 and provides valuable information on this issue.
The document contains many valuable statements about preventing infection and other mechanical complications. The most important statement for the question at hand is:
“The consultants and ASA members agree that a chest radiograph should be performed to confirm the location of the catheter tip as soon after catheterization as clinically appropriate. They also agree that, for central venous catheters placed in the operating room, a confirmatory chest radiograph may be performed in the early postoperative period. The ASA members agree and the consultants strongly agree that, if a chest radiograph is deferred to the postoperative period, pressure waveform analysis, blood gas analysis, ultrasound, or fluoroscopy should be used to confirm venous positioning of the catheter before use.”
In the ASA statement above, pressure waveform and blood gas analysis will rule out arterial placement but it will not confirm where the tip is located. Numerous veins are identified as sites for malpositioned, suboptimal, or aberrant locations for a CVAD tip and these locations are known for increasing the risk of complications. One other issue with the ASA guideline is the allowance of tip locations in veins distal to the vena cava or cavoatrial junction. This position is in opposition to other guidelines stating the tip location should be located in the area extending from the distal superior vena cava to the upper right atrium with the most preferred site at the cavoatrial junction. For femoral insertion sites, the tip location should be above the diaphragm in the inferior vena cava at or near the cavoatrial junction.
New technologies such as ECG and ultrasound are growing in application to confirm tip location with less reliance on a chest xray. ECG to confirm tip location, a practice this is prevalent in Europe, uses the stylet wire inside the catheter as an internal lead. When the wire reaches the SA node, the P wave is at is tallest point. This method works on most patients except those with cardiac anomalies that prevent a visible P wave from being detected on the ECG tracing. Ultrasound for tip location requires a special probe, the ability to locate the proper “acoustic window” for each patient, and the ability to interpret the findings. As we move toward implementation of these technologies, our goal should be to standardize practice across all locations. What is correct tip location and its confirmation should be the same for all patients in all healthcare facilities and departments.
Author: Lynn Hadaway
Lynn Hadaway has more than 35 years experience in infusion nursing and adult education. Her experience comes from multiple acute care settings, healthcare manufacturing, continuing professional education.