Central Venous Catheters (CVC) are being used in both intensive care units and general wards for multiple purposes. During CVC cannulation, some complications may occur. One of those complications is Extra systole or arrhythmia that can be caused due to irritation of the endocardium by the metallic guidewire, especially if the guidewire is inserted to an excessive depth2, 3. This phenomenon is not rare. A previous study4 found that 41% of procedures resulted in atrial arrhythmias, and 25% produced some degree of ventricular ectopy. Most arrhythmias resolve spontaneously or when the guidewire is withdrawn to an adequate depth2. Studies have shown that the most common arrhythmia associated with guidewire insertion is atrial premature contraction 2, 5. However, there is also evidence of potentially life threatening arrhythmias such as persistent supra ventricular tachicardia6, complete heart block7 and sustained ventricular tachycardia that subsequent cardiac arrest8 following the procedure. Wire irritation to the endocardium should be avoided to prevent these rare but dangerous complications. The risk factors for developing an arrhythmia include insertion of wire longer than 20cm2, female gender and patient height of under 170cm5, and CVC insertion from the right subclavian position.4 These factors indicate that the higher chances of tip entering right atrium or ventricle, the greater the chance of arrhythmia. Guidelines for CVC insertion specify methods for verifying venous guidewire cannulation before dilation of the vein. Methods for confirming that the wire resides in the vein include, but are not limited to trans- esophageal echocardiography (identification of the wire in the superior vena cava or right atrium), continuous electrocardiography (identification of narrow-complex ectopy), or fluoroscopy.9 None of these methods are routinely practiced, and performers insert the guidewire to a random length, sometimes causing short extra systole (when the wire touches the endocardium) as verification for venous wire cannulation. There is wide variation in distance from skin puncture site (internal jugular versus subclavian) and side of puncture (right versus left) and the right atrial-cava junction. One study measured these distance variations and found 12cm-25 cm gap.10 there is no “one size fits all” distance to avoid endocardial irritation during CVC wire insertion. A previous study1, by our group describing the utilization of point of care ultrasound for CVC tip placement, observed that during CVC insertion through Subclavian Vein (SCV) or the Internal Jugular Vein (IJV) the guide wire is sometimes advancing to the Inferior Vena Cava (IVC), and in other times to the right atrium. When the guidewire went to the IVC there was no extra-systole. In this study, we thought to describe guidewire migration location during real time CVC cannulation (right atrium versus IVC), and to report the association between the insertion site and side of the CVC (internal jugular versus subclavian, right side versus left side) and the location of guidewire migration, Right Atrium(RA)/Right Ventricle (RV) versus IVC guidewire migration. The importance of this finding is related to the fact that guidewire migration to the IVC will not result in arrhythmia or an extra systole, whereas guidewire migration to the right heart has the potential for arrhythmia. To our knowledge, the chance for arrhythmia during guidewire insertion, hence the ratio of wire migration to the IVC versus the RA was never described before.

Study Population

This cohort study included one hundred and sixty-six patients admitted between 2014 and 2020 in the ICU in Soroka University Medical Center who have required upper torso CVC (SCV or IJV) using Seldinger guidewire insertion. Patients were excluded if they had recent abdominal surgery precluding the subcostal view or if real time point of care ultrasound guidewire verification could not be made, or that the guidewire location was unknown. This is a retrospective study of the prospectively and systematically collected data on CVC insertion under real time Trans thoracic ultrasound. The data was collected from the medical ICU in the Soroka medical center database of documented central lines inserted during the study years. Many of these central lines were inserted under real time ultrasound guidance with documentation of the guidewire migration site during the procedure. This was done as part of the protocol of central line insertion that was developed in this ICU6 and is part of the routine of CVC insertion. We documented the date, the site and side of insertion, and the location where the guidewire tip was identified in the right heart or the IVC. Also, in random cases, we have documented if there were extrasystole or arrhythmias noticed on the monitor.

CVC Procedure

All catheters were inserted percutaneously using the Seldinger technique. It was inserted on one of four sites: The right internal jugular vein, the left internal jugular vein, the right subclavian vein, and the left subclavian vein. When the procedure was over, the guide wire’s location was verified using a Trans thoracic US in the subcostal view, it was documented, and the CVC was sutured to the skin and covered sterilely.

Use of US

There was a use of cardiac US during the procedure to identify the location of the tip of the guidewire inserted to the right heart or IVC in real-time, and to measure the depth of the guidewire when the tip of the guidewire is in the SVC. This is the method that we use, as the standard of care, for CVC insertion under US guidance for proper CVC tip placement as further explained in our previous study 1. The subcostal view is being used while inserting the guidewire to the central vein. Using the US, we look for the tip of the guidewire in the heart. Then we document if the guidewire went to the IVC, to the RA, or RV. The guidewire will be pulled back until the tip of the guidewire is seated in the SVC. Then the depth of the wire from the skin to the SVC is measured and documented, this is the depth that the central line will be inserted into.

Ethics

This study was approved by the Helsinki committee of the Soroka Medical Center, Beer Sheva, Israel (Chairperson Prof R. Hershkovitz) on 12 July 2018.

Statistical Analysis 

Patient characteristics are presented as mean ± SD for continuous variables with a normal distribution and categorical variable are presented as frequency (%). In our uni-variable tests we compared means using the independent-samples t-test and compared proportions using Chi square test and Fisher exact test. To examine the guidewire migration (IVC vs. RA/RV) a logistic regression was conducted with the insertion site being the primary independent variable. Variables having clinical significance were add to the regression. An odds ratio (OR (, P-value and confidence interval was reported. A two-sided P-value <0.05 was considered statistically significant for all statistical tests. P-values reported was rounded to two decimal places. All statistical analyses were performed using SPSS version 24.0 (IBM Corp, 2015).

Two hundred and seven patients were admitted to the medical ICU in Soroka University Medical Center in the years 2014-2020 who have required upper torso CVC insertion. Forty-one were excluded from this study due to missing data (see Figure 1). One hundred and sixty-six CVC cannulations from the IJV or the SCV were conducted and documented in this study. There were no differences in most of baseline characteristics between the two groups.  Table 2 and table 4 explicit the baseline characteristics of the patients in the study.

Two thirds of upper torso CVC were inserted to the subclavian vein (64%) and a third to the internal jugular vein. About two thirds of CVCs were inserted from the right side (68.7%). About two thirds of wires migrated to the RA/RV and a third to the IVC (Table 1,2).

Table 1: Patients Baseline Characteristics.

Table 2: Site and side of CVC insertion and wire migration site.

Although we had no systematic data collection of arrhythmias or extrasystoles documentation during CVC insertion, all 15 documented arrhythmias occurred when the wire migrated to the RA/RV and not when IVC wire migration was documented. The site of CVC insertion was not associated with IVC or RA/RV wire migration (33.9% versus 33.6, IJV and SCV respectively, P=0.97, Table 3a). The side of CVC insertion was also not associated with IVC or RA/RV wire migration (P=0.22 Table 3b), nor the side and site together (P=0.66, Table 3c). The Logistic regression model for wire migration location was not influenced by the side or the site of the CVC (Table 4).

Table 3a: CVC insertion site and side.

Table 3b:

Table 3c: Right side.

Table 4: Logistic regression; tip placement in the RA\RV.

We have found that during the insertion of CVC using the Seldinger technique, 33% of guidewires migrate to the IVC, with no potential for any guidewire induced arrhythmia. We also found no association between site and side of CVC insertion and the site of guidewire migration; hence choosing the subclavian over the internal jugular on any side will not increase the rate of guidewire migration to the IVC or the RA/RV. We believe that physicians who perform central venous catheter insertion should be familiar with the relatively high IVC guidewire migration prevalence. Some operators verify the “correct” location of the wire when there is tachycardia on the monitor. This technique should not be encouraged for wire placement confirmation because of the risk for right heart guidewire migration hence the potential risk for life-threatening arrhythmia and low sensitivity for such tachycardia. We show that over 30% of cases will not have the potential for tachyarrhythmia. Also, Performers should know that choosing a specific site of insertion (SCV versus IJV) or specific side (right versus left) will not increase or reduce the chance for RA/RV guidewire migration, hence, the chance for iatrogenic arrhythmia. There are a few possible limitations to this study. First, all the patients in the study were treated in the same medical ICU in Soroka medical center and by a limited number of senior physicians and residents, limiting the generalizability. Secondly, extrasystole was not routinely documented, so although the documented ones occurred only when the wire was identified in the RA/RV, we did not design the study to prove this observation. Lastly, only 20 patients received left-sided IJV CVC. This limited sample size may influence the results as well.

Clinicians who perform upper torso CVC insertion should be aware that 33% of guide wires migrates to the IVC, and not to the RA/RV. When a guidewire migrates to the IVC, no extra systole is observed. There was no association between the site of insertion, side of insertion, and the site of guidewire migration. Tachycardia on the monitor should not be used as a sign for correct placement of the central line during this procedure.

Ethics approval and consent to participate: This study was approved by the Helsinki committee of the Soroka Medical Center (Chairperson Prof R. Hershkovitz) on 12 July 2018. Consent for publication: Not applicable.

The datasets used and analyzed during the current study is available from the corresponding author on reasonable request. Competing interests: The authors declare that they have no competing interests.

None

DR- writing the manuscript, data collection.

RS- data collection, data analysis.

OG- data collection and the study design.

YA- study design.

LF- study design, data collection, data analysis, writing parts of the manuscript.

Not applicable.

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