Brief Report

Needle and guidewire visualization in ultrasound-guided internal jugular vein cannulation^?

James H. Moak MD, RDMS ^a,?, Michael S. Lyons MD ^b,

Stewart W. Wright MD ^b, Christopher J. Lindsell PhD ^b

^aDepartment of Emergency Medicine, University of Virginia, Charlottesville, VA 22908, USA

^bDepartment of Emergency Medicine, University of Cincinnati, Cincinnati, OH 45267, USA

Received 16 October 2009; revised 5 January 2010; accepted 7 January 2010

Abstract

Study objective: Reimbursement for ultrasound-guided central lines requires documenting the needle entering the vessel lumen. We hypothesized that physicians often successfully perform ultrasound- guided internal jugular (IJ) cannulation without visualizing the needle in the lumen and that guidewire visualization occurs more frequently.

Methods: This prospective, observational study enrolled emergency physicians performing ultrasound- guided IJ cannulations over an 8-month period. Physicians reported sonographic visualization of the needle or guidewire and recorded DVD images for subsequent review. Outcome measures were the proportion of successful procedures in which the operator reported seeing the needle or guidewire in the vessel lumen and the proportion of successful, recorded procedures, in which a reviewer noted the same findings. Procedures were deemed successful when functioning central venous catheters were placed. Fisher exact test was used for comparisons.

Results: Of 41 attempted catheterizations, 35 (85.4%) were successful. Eighteen of these were recorded on DVD for review. The operator reported visualizing the needle within the vessel lumen in 23 (65.7%) of 35 successful cannulations (95% confidence interval [CI], 47.7%-80.3%). In 27 cases, the operator attempted to view the guidewire and reported doing so in 24 cases (88.9%; 95% CI, 69.7%-97.1%). On expert review, the needle was seen penetrating the vessel lumen in 1 (5.6%) of 18 cases (95% CI, 0.3%- 29.4%). Among recorded procedures in which the operator also attempted wire visualization, the reviewer could identify the wire within the vessel lumen in 12 (75.0%) of 16 cases (95% CI, 47.4%-91.7%).

Conclusions: During successful ultrasound-guided IJ cannulation, physicians can visualize the guidewire more readily than the needle.

(C) 2011

^? Presented as an abstract at the Society for Academic Emergency Medicine, New Orleans, La., May, 2009.

* Corresponding author.

E-mail address: [email protected] (J.H. Moak).

Introduction

Internal jugular vein cannulation has been shown to be safer with real-time ultrasound guidance than without [1-3]. The Agency for Healthcare Research and Quality lists this technique for central line placement among the 11 practices with the greatest strength of evidence for improving

0735-6757/$ - see front matter (C) 2011 doi:10.1016/j.ajem.2010.01.004

patient safety [4], and many consider ultrasound guidance to be the standard of care [1-3,5-8]. Given the evidence in support of using ultrasound, it is reasonable that an incentive exists within reimbursement guidelines to encourage clin- icians to adopt this practice. The 2009 Current Procedural Terminology code requires “concurrent real-time ultrasound visualization of vascular needle entry” into the vessel with image documentation [9]. Although this requirement may prevent fraudulent billing, visualizing the needle tip within the vessel lumen is not known to be correlated with procedural success.

Anecdotally, we have observed that a hyperechoic reflection produced by the shaft of the needle is often seen superficial to the vessel at the time a “flash” of blood is seen in the syringe but that the needle tip may not be observed within the vessel lumen on ultrasound. Attempting to procure an image for billing purposes after blood has been successfully aspirated could lead to injury, delay, or procedural failure. Nonvisualization of the needle tip in the vessel lumen during successful IJ cannulation is likely to be especially common when using a short-axis (horizontal) scanning plane as is customary at many institutions including ours.

A reasonable alternative for proper documentation of the use of ultrasound may be sonographic demonstration of the guidewire within the vessel lumen (Fig. 1). This added step in the procedure, performed before dilating over the wire, has been suggested as a measure that may prevent inadvertent cannulation of the carotid artery [10]. Our department encourages this technique as a routine practice during IJ vein cannulation. We are unaware, however, of any studies evaluating the feasibility of wire visualization. The aim of this study was to determine whether sonographic visualization of the needle tip or the guidewire within the vessel lumen is more commonly observed with successful IJ cannulation.

Methods

Study design and setting

This was a prospective, observational study enrolling a convenience sample of emergency physicians performing ultrasound-guided IJ vein cannulation. The study was conducted in a large, urban, academic emergency department with an annual census of 85 000, between September 2008 and April 2009. The study was approved by the investiga- tional review board.

Selection of participants

Emergency medicine residents and attendings were eligible for enrollment. Informed consent was obtained from all physician participants; the investigational review board granted waiver of informed consent from patients as this study sought only to observe routine procedural practice.

Fig. 1 Sonographic image demonstrating the IJ vein with guidewire within the lumen (arrow).

All ultrasound-guided IJ vein cannulations performed in the emergency department were eligible for inclusion based on the availability of a study assistant or one of the investigators. All procedures were performed using a Sonosite M-Turbo (Sonosite Inc, Bothell, Wash). In didactic sessions before and during the study, physicians were encouraged to attempt wire visualization with ultrasound before dilation and catheter placement. A sonogram revealing a guidewire within the IJ lumen was shown during lecture, but no practice sessions were held. Operators performed a median of 12 (range, 0-200) ultrasound-guided central lines before

participation in the study.

Data collection and processing

Operators were asked to notify a study assistant or investigator before attempting ultrasound-guided IJ cannula- tion and to capture dynamic, sonographic images of the procedure on a DVD recorder for later review. After attempting the procedure, operators were asked questions about the number of operators, operator level of training, complications, and success or failure of the procedure. They were also asked whether Sonographic findings such as vein compressibility, the needle within the lumen, or the wire within the lumen were observed and whether any attempt to visualize the wire was made. Responses to questions were recorded by study assistants on a data sheet. Successful procedures were defined as placement of functioning central venous catheters. Additional data recorded included patient age, sex, and number of puncture attempts not including needle redirection. The DVD images recorded at the time of the procedure were subsequently reviewed by the primary investigator. This investigator, who is credentialed as a Registered Diagnostic Medical Sonographer, used a separate data sheet to record the presence or absence of sonographic findings blinded to physician identity, sonographic findings noted by the operator, success of the procedure, and

that required either switching to the contralateral side (one patient) or changing operators (one patient) were regarded as separate procedural encounters. Of 41 attempted catheteriza- tions, 35 (85%) were successful, and 18 of these were recorded on DVD. As shown in Table 2, the operator reported visualizing the needle within the vessel lumen as required for reimbursement in 23 (66%) of 35 successful

Table 1 Patient, operator, and procedural characteristics among 41 attempted IJ vein cannulations

Patient age (y), median (range) Male sex, n (%)

IJ location, right side (%) Complicating factors, n (%) ? Obesity

Coagulopathy Agitation

Operator level of training, n (%) R1

R2 R3 R4

Attending

Single-operator technique, n (%) No. of sticks

Mean, median (range) Successful, n (%) Complications, n (%) Arterial puncture Pneumothorax Hemothorax

* As reported by operator.

57 (22-81)

23 (56)

23 (56)

5 (12)

2 (5)

2 (5)

7 (17)

31 (76)

1 (2)

1 (2)

1 (2)

30 (73)

1.9, 1 (1-10)

35 (85)

5 (12)

0 (0)

1 (2)

cannulations (95% confidence interval [CI], 48%-80%). Compressibility of the vein by the transducer was noted in all cases, both successful and unsuccessful. During successful procedures in which the operator attempted wire visualiza- tion with ultrasound, the wire was observed in the lumen in 24 (89%) of 27 cases (95% CI, 70%-97%). On expert review of recorded successful procedures, the needle was identified within the vessel lumen in only 1 (6%) of 18 cases (95% CI, 0%-29%); among those in which the operator attempted wire visualization, the reviewer could identify the wire within the vessel lumen in 12 (75%) of 16 cases (95% CI, 47%-92%).

complications. Medical records were reviewed by depart- mental staff for complications not identified by operators at the time of the procedure.

Primary data analysis

The primary outcome measure was the proportion of successful IJ cannulations in which the needle and/or guidewire were visualized within the vessel lumen, both by the operators and upon expert review. Fisher exact test was used for comparisons. Analyses were performed using SPSS (SPSS, Inc, Chicago, Ill). Confidence intervals for propor- tions were computed in Microsoft Excel (Microsoft Corpo- ration, Redmond, Wash) using the score method with continuity correction.

Results

Patient, operator, and procedural characteristics are presented in Table 1. For statistical analysis, failed attempts

Discussion

Numerous studies have demonstrated the benefits of ultrasound in assisting with IJ vein cannulation [1-3]. As is appropriate, billing codes exist to provide incentives for physicians to learn and apply the skills necessary to perform this procedure using ultrasound. Although the current billing requirement for image documentation of the needle entering the vessel lumen may seem intuitively feasible, our study shows that among successful cannulations, physicians report observing sonographic venipuncture only two thirds of the time. An expert reviewer analyzing recorded images of the procedure without the responsibility of direct patient care observes the needle in the lumen only 6% of the time. Although not addressed by our study, we expect that even less often would the operator, aided by an assistant, be able to capture a static image of the needle entering the vessel lumen. The requirement for sonographic documentation of the moment of venipuncture, therefore, seems inappropriate. If a requirement for image documentation is necessary, however, an alternative image could be considered.

Other potential candidates for image documentation are the guidewire, the dilator, and the catheter itself. Although we believe the catheter is amenable to sonographic visualization, demonstrating its presence in the vessel lumen after the procedure has been performed offers no

Table 2 Sonographic visualization of the needle and guidewire within the vessel lumen during successful ultrasound-guided IJ vein cannulation

Observer Needle (observed/no. of

successful procedures)

23/35 (66%; 95% CI, 48%-80%)

1/18 (6%; 95% CI, 0-29%)

Guidewire (observed/no. of attempts to view)

24/27 (89%; 95% CI, 70%-97%)

12/16 (75%; 95% CI, 47%-92%)

P

Operator

Reviewer (when recorded on DVD)

b.05 b.001

proof that ultrasound was an integral part of the procedure. A physician relying on landmarks alone could fraudulently bill for ultrasound simply by capturing an image of a previously placed catheter. One could conceivably procure an image of the dilator, but doing so after its placement over the guidewire would have little merit as a means of avoiding dilating the wrong vessel. The most reasonable alternative image, therefore, would be one demonstrating proper placement of the guidewire.

To our knowledge this prospective study is the first to examine the feasibility of sonographic wire visualization during IJ catheterizations. Our findings reveal that when wire visualization is attempted, the guidewire can be seen within the vessel lumen more commonly than the needle. Although this study was not powered to detect a decreased complication rate, we believe that this step is important for avoiding inadvertent carotid artery cannulation. By demonstrating that the wire resides in the collapsible IJ vein rather than the less compressible, pulsatile, and thicker-walled carotid artery, the likelihood of arterial cannulation is diminished. Our practi- tioners were able to visualize the wire within the lumen on ultrasound 89% of the time without extensive practice. We contend that with minimal additional training, operators’ observance of the wire in successful cannulations would approach 100%. In contrast to the moment of needle entry into the vessel lumen, which occurs transiently at a time when the operator must immediately attend to other tasks and which may occur beyond the scanning plane of the transducer, the guidewire is more suitable for sonographic imaging. Not only is it designed to be left in place longer than the needle, it also courses further within the vessel, making sonographic visualization feasible over a greater length of the vein.

Typically, aspiration of bright, pulsatile blood makes inadvertent carotid puncture clinically obvious. In some cases, such as in hypotensive patients, the distinction between venous and arterial blood is more subtle. Techni- ques used by some practitioners to discern venous from arterial puncture include attachment of intravenous tubing to the needle, assessment of a pressure waveform, and rapid blood gas measurement of aspirated blood. These techniques require holding the needle stationary for a more prolonged period, risking dislodgement or vessel injury, and manipu- lating the proximal end of the needle. In contrast, sonographic inspection of the IJ vein for the presence of a wire is quick, requires no added equipment, poses no risk of injury to surrounding structures, and appears to be easily learned. If the operator has difficulty visualizing the wire initially, it is quite easy to tilt the probe back and forth until the wire is seen or alternate between short- and long-axis orientations. In our view, these maneuvers are inadvisable when a sharp needle is located in the vessel lumen during the moment of venipuncture, especially if the sole purpose is to generate an image suitable for billing. In our experience, a long-axis approach to wire visualization is preferable.

This study should be interpreted in light of several limitations. Most importantly, our findings may not be

applicable to IJ catheterizations performed using a long-axis (longitudinal) scanning plane. Although a long-axis ap- proach allows the operator to ascertain needle depth more accurately, this technique requires more skill and may not be feasible in some patients due to the proximity of the clavicle. We were surprised to note a significant discrepancy between intraluminal needle visualization as reported by the operator vs that observed by the reviewer. This difference may have been caused by response bias; operators, who were in most cases residents, may have responded affirmatively that they observed the needle in the lumen sonographically because they perceived, correctly or not, that this finding is procedurally important or an expectation of the investigators or the attending physician. Operators may also have overestimated the frequency of this sonographic finding because they intuited that the needle penetrated the vessel wall as soon as they observed blood in the syringe. Another possible explanation for discrepant findings between re- viewer and operators is that the reviewer had the opportunity to replay DVD images on any questionable cases to ascertain more certainly whether needle entry was observed, whereas operators had only one fleeting, real-time viewing of sonographic images and had to recall what they had observed upon completion of the procedure.

Another limitation was that only half the procedures were properly recorded on DVD for subsequent review. Although conceivable that some aspect of the operators’ technique varied between recorded and nonrecorded procedures, we believe this to be unlikely. Also, operators made no attempt to visualize the guidewire in nearly a quarter of successful cannulations. Attempted wire visualization in all cases might have produced different results. Finally, this was a small study aimed at establishing the feasibility of visualizing the needle vs the guidewire in the vessel lumen. Larger studies will be necessary to confirm our findings and demonstrate a safety benefit to routine wire visualization.

Conclusion

During successful ultrasound-guided IJ cannulations, sonographic visualization of the needle penetrating the vessel lumen often does not occur. Guidewire visualiza- tion, which has been suggested to prevent inadvertent carotid artery cannulation, is more reliable. We recom- mend that Current Procedural Terminology codes be modified to allow sonographic documentation of the guidewire rather than the needle tip, in the vessel lumen for purposes of reimbursement.

Acknowledgments

The authors wish to thank Carla McTaggart, BSN, and her staff for assistance with data collection, and Pattie Smith, RDMS, for her assistance in study enrollment.

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