Spontaneous Knot Formation in a Central Venous Catheter

Background

Access using intravascular devices is used in the management of patients under different indications to avoid the various peripheral punctures, or even in cardiopulmonary resuscitation and life-saving measures [1,2].

The devices most commonly used in intensive care units (ICU) are venous. The use of central venous catheterization (CVC) was first introduced by Dr. Werner Forssmann in 1929, who self-inserted a ureteral catheter into the cubital vein up to the right atrium [3]. In 1953, the catheterization technique was protocoled by the radiologist Sven Ivar Seldinger, using a metallic guidewire in the subclavian vein [4] and since then the access technique has become safe and is recommended by some authors [5].

Currently, the catheter is inserted mainly through a needle into the jugular puncture, subclavian, or femoral veins using the Seldinger technique. The CVC can have 1, 2, or more routes, and the choice will depend on the therapeutic complexity [6]. Proper catheter maintenance is essential to minimize damage and achieve the longest useful catheter life [2].

Most treatments require prolonged time; therefore, it is important that CVCs have a long duration, either for general medications administration to decompensated patients [7] and hemo-dynamic monitoring when administering vasoactive drugs [8], or for parenteral diets [9,10].

CVC is an invasive procedure and, as such, it is not exempt from complications [7]. The location choice for the CVC passage depends on factors such as the physician’s expertise with the technique, in identifying anatomical landmarks, and the risk of minor complications related to catheter insertion and manipulation [11].

Numerous mechanical, infectious, and thrombotic complications have been reported with use of CVCs [12,13]. Mechanical and thrombotic complications during catheter insertion include hematoma formation, pneumothorax, hemothorax, thrombosis, phlebitis, gas embolism, hemorrhage, and inadvertent arterial puncture [12]. Complications associated with catheter manipulation tend to be infections, such as sepsis [14].

A multicenter observational study with more than 10 000 patients found mechanical complications in 1.1% of patients undergoing CVC [15], and a retrospective ICU cohort study of 311 patients at a teaching hospital in Brazil reported a rate of 6% [16].

The knotting of an intravascular catheter is a very rare complication, first described in 1954 by Johansson et al [17].

The aim of this study is to report a case of a knot in the distal end of a mono-lumen CVC, formed after guidewire removal, inserted through the right internal jugular vein, and removed under local anesthesia. This study was approved by the Teaching and Research Committee – CAAE: 20940619.2.0000.5509.

Case Report

A 63-year-old male patient, a former smoker, with a previous angioplasty history and a non-pharmacological placement coronary stent in a marginal branch of the circumflex coronary artery 30 days before the current presentation, progressed to junctional bradycardia and cardiogenic shock.

He was transferred to the reference hospital ICU in the city of São Paulo/SP, Brazil. On admission, he was asymptomatic, with clinical and hemodynamic stability without the use of vasoactive drugs. He presented sinus rhythm and 99% oxygen saturation on room air.

He had a CVC inserted in the right jugular vein but without flow. As reported in medical records, the CVC was inserted through the right jugular without the aid of ultrasound, with blood flow and blood reflux present. There were no reports of difficulties or the number of catheterization intentions. However, when the patient was asked about the number of attempts to pass the catheter, he reported that more than one doctor tried the procedure. Efforts were made in an attempt to unblock the CVC, such as washing with saline solution and gentle catheter twisting, but without success. Thus, we opted for CVC removal and creating a new central access puncture. There was no difficulty in removal, up to about 2 cm for the catheter exteriorization, when some resistance was noted, with excessive catheter traction associated with pain at the CVC insertion site.

At that time, we considered the hypothesis of a knot close to the end of the catheter, and an anteroposterior chest X-ray was performed (Figure 1). After the diagnostic suspicion was confirmed, venotomy was performed under local anesthesia with 2% lidocaine without a vasoconstrictor. The catheter was successfully recovered without fragmentation, as analyzed after its removal (Figure 2).

Discussion

The use of CVC has become an essential procedure in ICU routine in the care of critically ill patients [18]. Although the procedure is generally safe, it is estimated that around 15% of patients admitted to the ICU have complications related to CVC [18,19].

Catheter occlusion can occur due to a variety of conditions and even for no apparent reason. It is reported that this complication occurs in 36% of CVC cases [20]. Distal CVC obstruction is a rare complication [5,15], with most of the reported cases related to pulmonary artery catheters, probably because they are more flexible, longer, and do not have a guidewire [21].

In the 50 years from 1950 to 2000, only 113 cases of CVC knot were reported [21]. It is a serious complication that, in addition to the difficulties in its removal, can interrupt blood flow, require surgery and, depending on the location, lead to death [22].

CVC depends exclusively on human action, so some basic points must not be overlooked so that the benefits always outweigh the risks inherent in this invasive procedure. With this in mind, the team must be familiar with anatomical landmarks such as vascular anatomy and underlying structures; choose the exactly correct catheter type; should know the puncture site and the vascular insertion techniques; must strictly follow the described technique; be careful in asepsis and antisepsis in performing the puncture; and identify and recognize early complications and treat them [12].

Our patient was admitted at the unit with CVC installed, with no flow, and we only had basic information about the initial catheter passage procedure. We did not know the procedure details, the difficulties encountered, the number of attempts made, or even if there was a preview catheterization in the same vein. The fact attracted the doctors’ attention because the inability to infuse solutions in the catheter lumen can lead to immediate therapy suspension and the need for a new procedure [23].

It is known that advancing a CVC without proper care can lead to knot formation [25], and making more attempts at catheterization is associated with higher risk of complications [6,24]. As with the vein cannulation previously used for CVC, thrombus formation is common, and thrombosis is also a potential cause of the formation of a loop, entanglement, and knotting [26].

CVC knot cases have been reported in neonates for more than 30 years. Being careful not to advance the catheter too far in the vein of choice helps prevent this complication [25].

Some practices are recommended by the American agency responsible for research and quality in health care with the aim of increasing safety in the management of CVCs, with the use of ultrasound to guide central venous punctures being one of them. This recommendation was based on a meta-analysis that reviewed 8 randomized clinical trials [27]. A prospective multicenter study showed that the echo-guided technique is a diagnostic modality with moderate sensitivity and high specificity to detect poor catheter positioning [28]. Ultrasound makes it possible to assess the vein that will be punctured under direct vision, reducing accidents and other complications [18], and when available, its use should be encouraged [27,29], even in children [30]. In this present study, such a procedure was not available.

A simple chest X-ray to confirm the final catheter position should always be requested immediately after catheter insertion, identifying possible complications that may have gone unnoticed [31]. Radiological follow-up after the procedure in patients with difficult anatomy is essential [32]. Some authors recommend performing a late chest X-ray in the presence of any possible complication [33], just as was done in our patient.

The internal jugular vein, chosen for venous access in present case, allows a high success rate in puncture, together with low rates of serious complications [34]. A higher rate of infection and thrombosis is described when CVC is performed through the femoral vein, in comparison with the subclavian vein [11,35,36].

In the present case, the professional’s experience in immediately suspecting a late CVC complication was essential to avoid major complications, such as catheter fragmentation and venous injury. However, it was not possible to exactly determine the cause of its formation. We believe that the various previous attempts of catheterization of the central vein reported by the patient, as well as a probable blood whirling caused by the cardiac arrhythmia, or else a possible improper catheter traction during the patient transfer, may have contributed to the knot formation.

Catheter wire entanglement usually results in a knot, as seen in this case, in which there was a loop in the catheter. There are several options reported in these cases regarding the possibility of removing the catheter: traction application, in which the knot (of entanglement or loop) is tightened with the catheter removal done smoothly through an enlarged insertion site [37], venotomy under local anesthesia [38,39], and knot manipulation under fluoroscopy by radiology [40]. In some cases, surgical procedures may also be necessary [41]. In a 2002 literature review, 36% of cases required a surgical procedure to remove the catheter knot, and it was associated with the knot location [21].

To reduce the risk of this occurrence, when catheters are introduced, some precautions are needed, such as incision in the skin at an adequate depth, elimination of excessive force when inserting the vessel dilator and catheter on it, keeping its introduction absolutely immobilized without abrupt maneuvers [42], observing the fluid flow as the catheter is inserted, and not advancing the catheter when there is resistance [26,43].

Such efforts to prevent complications should be routinely adopted, improving the safety and quality of care in ICUs. All these precautions improve the doctor’s ability to effectively neutralize problems in the clinical environment, and they need to be combined and integrated [44].

Conclusions

Despite the rarity of intravascular catheter knots, it is important to note that this is a possible late complication that must be considered when there is absence of flow and difficulty of withdrawal associated with referred local pain.