Central venous catheter (CVC) placement is a vital medical procedure performed more than 5 million times each year in the United States.1 CVC cannulation can serve multiple purposes: to administer vasoactive drugs and parenteral nutrition, facilitate volume resuscitation, provide hemodynamic monitoring, and aid frequent blood sampling.1,2 While this invaluable procedure proves helpful in patient care, it is not without risks. Some of these include pneumothorax (PTX), hemothorax, arterial puncture, hematoma, nerve injury, chylothorax, brachial plexus injury, arrhythmia, air embolus, and possible death.2,3
Historically, the standard method for CVC placement has been the landmark technique, which relies on the identification of palpable and visible anatomy with known relationships to the desired vein.2 In 1984, Legler and Nugent published the first study4 examining the use of ultrasound (U/S) guidance in CVC placement. Many medical professionals have investigated the benefits and disadvantages of U/S-guided CVC placement since that time. The advantages of U/S guidance over the landmark method include detection of anatomical variations, exact vessel location, avoidance of central veins with pre-existing thrombosis, and ease in guide wire and catheter placement after initial needle insertion.3
At Lancaster General Hospital in Lancaster, Pa., the trauma service is staffed by trauma surgeons, NPs and PAs. Members of the trauma service have been trained and credentialed to use U/S guidance to perform CVC placements. The NPs and PAs on the trauma service played a primary role in the initiation and implementation of U/S as an adjunct for CVC placement. U/S guidance is used selectively for high-risk patients at the hospital, especially those with coagulopathy, morbid obesity or other conditions that could potentially complicate CVC insertion. Our team of physicians, NPs, PAs and researchers hypothesized that the use of U/S in CVC placement would significantly decrease complication rates.
The trauma intensivists at our Level II trauma center are in-house 24 hours a day, and as a result they are primarily consulted for CVC placement throughout the hospital. Ultrasound is most often used in high-risk patients with conditions such as cachexia, morbid obesity or coagulopathy. We conducted a retrospective study from September 2007 to June 2012 to review the complication rate of CVC placement. In all cases, the internal jugular or subclavian veins were used for U/S guided CVC placement. For landmark CVC placement, the internal jugular or subclavian veins were also used.
An M-Turbo U/S system was used to guide CVC insertions. In all cases, CVC placement was performed by a trauma surgeon or an NP or PA dedicated to the trauma service. Complications included PTX, bleeding and improper placement of the central line. Postprocedure chest x-rays and operative notes were reviewed on all CVC placements to assess for complications. A senior surgeon reviewed all cases with complications.
Patients were divided into those who received CVC via U/S (+U/S) and those who did not receive CVC via U/S (-U/S). We performed a Pearson's chi-square analysis to assess complication rates between groups and a binary logistic regression to determine whether provider type (surgeon vs. NP or PA) was a significant predictor of a line complication. We then used Pearson chi-square analysis to compare the complication rates according to provider type in the stratified U/S groups. A p-value < 0.05 was considered significant.
In the study period, 857 patients received central lines. Due to missing data, 294 patients were excluded. This left a total of 563 central lines to be analyzed (346 -U/S [61.5%]; 217 +U/S [38.5%]). Physicians inserted 277 (67.1%) central lines and NPs or PAs inserted 185 (32.9%) central lines.
Two hundred forty-three (43.2%) CVCs were placed in the internal jugular and 319 (56.8%) were placed in the subclavian vein (Table 1). Eight patients experienced PTX, 17 experienced IP, and three experienced bleeding related to CLP. Twenty-three (6.7%) complications occurred in the -U/S group and five (2.3%) occurred in the +U/S group (p = 0.021 Pearson's chi-square analysis; Table 2).
Using binary logistic regression, provider type (surgeon vs. NP/PA) was not significant for line complication (OR 0.43; 95% CI 0.16-1.14; p = 0.090). After stratifying the data set into two groups (-U/S and +U/S), provider type was not significant for complication rates in the chi-square analysis of the -U/S group. However, NPs/PAs had significant lower complication rates than surgeons in the +U/S group (5.2% surgeons vs. 0.7% NPs/PAs, p = 0.035; Table 3).
While CVC placement is essential to the care of many hospitalized patients, the practice has long been associated with adverse outcomes. Traditional landmark-guided CVC placement bears overall associated complication rates of up to 15%, and these complications negatively impact both medical costs and patient health, including mortality.1,5
Many studies over the past 25 years have demonstrated the effectiveness of ultrasound-guided CVC cannulation in suppressing these negative outcomes. U/S-guided CVC insertion has proven to be the superior technique compared to the landmark method, and it is recommended by multiple influential regulatory organizations in the United States and Great Britain.3,6,7
Yonei and Sari published one of the first studies about ultrasound imaging and internal jugular catheter placement in 1986.8,9 Using a 5 MHz ultrasound transducer, 160 patients received U/S-guided catheterization, all performed successfully and without complications.9 A 1990 study by Mallory et al compared U/S-guided CVC insertion to the landmark technique and recorded an improvement in both the success rate and number of attempts to cannulate. Despite a small 27-patient sample, failed site cannulation dropped from 35% in the landmark technique group to 0% in the U/S-guided group. Furthermore, the U/S-guided group produced a mean attempt rate of 1.75, significantly less than 3.12 in the landmark group.10
In their noteworthy 1996 meta-analysis, Randolph et al identified similar results, showing that U/S guidance significantly increases cannulation success rate and decreases the need for repeated CVC insertion attempts.2 Of the eight published randomized, controlled trials analyzed in this meta-analysis, seven showed a lower placement failure rate for U/S-guided CVC placement, with the overall relative risk of 0.32 (95% CI: 0.18-0.55).The rate of complications using U/S was significantly lower than the control group, containing a relative risk of 0.26 (95% CI: 0.11-0.58). All trials showed reduced rates of multiple placement attempts, with an overall relative risk of 0.60 (95% CI: 0.45-0.79).2
More recent study data corroborate these results. Miller et al.'s 2007 prospective study demonstrated that US-guided CVC placement results in significantly fewer cannulation attempts and less time from the first stick to blood flash.8 Furthermore, although this study did not prove a significant reduction in complications (12% +U/S, 14% -U/S), the authors explained that with regard to subjective criteria, as many as 90% of users said they avoided complications by using the U/S image. U/S allows medical professionals to discern deviations from normal anatomy and address these issues accordingly.8,11 Additionally, a study conducted by Karakitsos et al found a decrease in the average number of attempts with the use of U/S (1.1 +U/S, 2.6-U/S). Their work also displayed a decreased number of hematomas (2+U/S, 38-U/S), hemothoraces (0+U/S, 8-U/S) and pneumothoraces (0+U/S, 11-U/S) with U/S-guided CVC insertion.12
Skeptics of this technique often point to the high economic cost of U/S guidance, arguing that hospitals must pay not only to purchase the machines, but also to train the staff and maintain the technology.2 Feller-Kopman's 2005 review of U/S-guided CVC placement explains that the idea that U/S guidance requires more training and manpower has never been proven,13 and the Agency for Healthcare Research and Quality states that only limited teaching of basic ultrasound physiology is necessary for successful use of the equipment.3
Miller et al showed that the U/S-guided technique results in absolute decreases in the time to blood flash and number of CVC attempts, regardless of clinician experience. Moreover, the study showed that landmark-guided CVC used 40% more cannulation kits per patient than U/S-guided insertion, thus elevating non U/S-guided CVC placement costs.8 Consider as well the cost of associated complications such as pneumothoraces, hemothoraces, hematomas and bloodstream infections.7 The improvement in quality of care through complication reductions, as well as decrease in demand on clinicians' time, may actually reduce overall costs.10
No published studies have compared the precision of CVC placement by surgeons with CVC placement by NPs and PAs. One study examined the utilization of NPs and PAs in trauma centers nationally and found that only a third of centers surveyed were employing them.14 Less than half of those centers permitted NPs and PAs to perform procedures including CVC insertions.14
NPs and PAs on the Lancaster General trauma service had significantly lower complication rates than the trauma surgeons. CVC placement with ultrasound is an easily acquired skill. Training NPs and PAs to perform this procedure could have hospital-wide implications. In community hospitals, NPs and PAs could aid with implementing sepsis bundles, hypothermia protocols, etc. In academic centers, NPs and PAs could potentially supplement the lack of coverage from resident work hour restrictions.
This study sought to shrink this gap in the research and determine how trauma patients' care is affected by U/S guidance. In comparing the complication rate related to landmark and U/S-guided CVC placement, the data support the findings of previous studies: U/S guidance significantly decreases the risk of complications for patients receiving CVC placement.
This study further supports the superiority of real-time ultrasound-guided CVC compared to the landmark technique. Put simply, U/S guidance is a safer practice and should be employed to promote the well-being of trauma patients in need of CVC placement.
Nevertheless, U/S guidance would be impractical and even detrimental to use in urgent trauma CVC placements. For U/S-guided line placement, extra equipment must be located and set up before cannulation, so prep time is longer than for the landmark-guided placement. In emergency situations when no time can be spared, medical professionals often need to insert a central line without waiting for U/S guidance to be set up. Therefore, U/S guidance should be used in all situations not requiring expedition.
We did not record failed placement attempts as a complication. Only complications that required follow-up care were considered as such. Almost all the central lines inserted with U/S were at the internal jugular, whereas those inserted without U/S were primarily at the subclavian. Only a small number of lines were placed in the subclavian with U/S and the internal jugular without U/S. Although both are standard sites for CVC placement, they have their intrinsic differences. If we were to eliminate the subclavian site, we would essentially remove the greater part of the control group.
That said, most clinicians who are not facile with the ultrasound technique will use the subclavian landmark technique because it is the most familiar method - despite that it has a higher complication rate, as shown by this study. A number of patients had missing variables and had to be excluded from this study. This was a retrospective review with all its inherent limitations.
In our study, trauma patients with CVC placement experienced significantly lower complication rates with U/S guidance. In addition, when using U/S, NPs and PAs had significantly lower complication rates than the trauma surgeons. The ability to place central lines with U/S guidance is an integral skill of trauma intensivists, and their advanced practitioners, and trauma centers should consider mandating the use of U/S guidance in all nonemergent CVC cannulations.
Amelia Rogers is a medical student at Jefferson Medical College in Philadelphia. At the time she wrote this article, she was the research coordinator for the trauma program at Lancaster General Hospital in Lancaster, Pa. Frederick Rogers is director of the trauma program at the hospital, Margaret Krasne is a research assistant, Daria Indeck and Ian Sale are physician assistants, and Daniel Wu and John Lee are trauma surgeons, at Lancaster General Hospital. The authors have completed disclosure statements and report no relationships related to this article.
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