Intraoperatory PICC tip detection in azygos vein and immediate correction: The role of intracavitary ECG and echocardiography: A case report

Introduction

Peripherally inserted central catheters (PICCs) are indicated and widely used for therapies of different duration, as chemotherapy, parenteral nutrition and intravenous antibiotics. ¹ PICC are related to optimal clinical benefits if inserted by trained health care professional following specific evidence-based protocols, ² including tip verification by intracavitary ECG (IC-ECG) and/or transthoracic echocardiography (TTE). Both methods have been proved to be accurate, immediate, provide real-time feedback, avoid radiation and related to increased procedural safety and efficiency.^3,4 However, primary misplacement of the catheter into accessory veins to the superior vena cava (SVC), can occur during catheter insertion. Malposition of the catheter tip has been repeatedly reported as a cause of serious complications, including thrombosis, vascular perforation or superior vena cava syndrome.^5–7 To date, no reports have described their combined intraoperative use for detecting central venous catheter misplacement into the azygos vein, nor has their value been discussed as a preventive strategy against the complications associated with delayed diagnosis. The present report describes a clinical case in which the simultaneous application of IC-ECG and TTE with bubble test enabled early identification of inadvertent azygos vein cannulation.

Case description

A 65-year-old male was diagnosed in our third level hospital with lung cancer. A PICC was requested to the PICC team for chemotherapy. Superficial ECG was performed on insertion day, showing a normal superficial P-wave (Figure 1(a)). Right basilic vein, 0.42 mm diameter, was selected for PICC insertion. Single-lumen, non-valved, 4Fr, polyurethane power-injection PICC was decided to be inserted by a vascular access specialist nurse following the SIP protocol. ² In the last 5 cm, catheter advancement was difficult. IC-ECG was performed with a multiparametric monitor connected to a sterile alligator-clip cable. A positive very high non-biphasic intracavitary P wave was clearly observed, although no biphasic P wave was obtained (Figure 1(b)–(d)) and PICC was not properly functioning in aspiration. Retraction and progression of the catheter into the vein was performed three times with same results: only maximal P wave and unavailability of aspiration. A bubble test was then performed with a convex probe through subxiphoid view: mild turbulence flux of microbubbles in right atrium (RA) were visible, but delayed for more than 2 s, meaning the tip was not in central position. At this point, tip couldn’t be verified in central position and operator decided to dress the catheter temporarily and send the patient for chest X-Ray (CXR). Lateral CXR showed PICC deviated into a posterior area for approximately 6 cm, along the course of the azygos vein (AV; Figure 2). After this, a sterile PICC replacement over-the-wire was performed. IC-ECG was again performed: this time, after biphasic P wave observation, maximal intracavitary P was verified (Figure 3) and the catheter presented no resistance during insertion. Also, bubble test revealed immediate laminar flux of microbubbles in the RA; and no resistance was observed during aspiration from the PICC, finally confirming the catheter was in central position.

OPEN IN VIEWER

Figure 1.

(a) Superficial ECG. Superficial P-waves can be observed (green circles). (b–d) IC-ECG after three different progression attempts. Irregular but positive intracavitary P-waves can be observed (green circles).

OPEN IN VIEWER

Figure 2.

Lateral chest X-Ray. PICC tip projected into azygos vein (white arrows).

OPEN IN VIEWER

Figure 3.

Intracavitary ECG trace after PICC over-the-wire substitution. Clear and regular intracavitary P-waves can be observed (green circles) after catheter insertion, observation of biphasic P wave and retraction.

Discussion

We present a case of a primary malposition of PICC verified by bubble test after a false positive IC-ECG tip identification during PICC insertion in a cancer patient. Tip verification of central lines is mandatory before using the device, in order to reduce complications such as thrombosis or malfunction.^1,7 International guidelines recommend using intraprocedural methods for tip localization ¹ such as IC-ECG and TTE. IC-ECG for tip verification is an accurate method based on variations of the intracavitary P wave^3,8 from superior vena cava (SVC) to the cavo-atrial junction (CAJ), and then to the RA. Catheter needs to be progressed into the vessel until the biphasic P appears; then, the catheter must be retracted until the peak of the P wave is seen and dressed in that central position. On the other hand, TTE method together with the bubble test have also proved to be a precise method for final position tip verification in adults when following a specific protocol ⁹ and when anatomical and/or clinical situation allows it. The method implies the immediate visualization (less than 1 s) of a laminar flux of saline microbubbles inside RA which confirms central tip position.

Although this case supports the strength of the integrated approach of IC-ECG and TTE with bubble test for tip verification, two manoeuvres should have been done before performing radiological examination: (1) longer retraction of the catheter while performing IC-ECG for avoiding recurrent AV, and in order to achieve biphasic P wave; (2) the use of a guide wire inside the PICC, in order to improve catheter’s turgidity, and facilitate retraction-progression manoeuvres. These can be considered as a limitation to the case. Most probably, the application of these two strategies would allow the catheter to follow the pathway to CAJ, obtaining an accurate IC-ECG result, avoiding the need of subxiphoid TTE and, most important, avoiding the use of CXR.

Even though the tip wasn’t in SVC, a very high (if compared to superficial) and positive P wave was visible. We presume that this false positive is due to the anatomical proximity of AV to lower third of CAJ, where the crista terminalis and sino-auricular node lie. That could be the reason why, while advancing the catheter, a high P wave was visible but no biphasic P wave aroused, and resistance was noticed in the last centimetres of catheter progression.

Many cases in literature have reported a central line misplaced into accessory veins.^5–7 In most cases, the discover of the malposition was done after insertion and, in some cases, after the catheter was already used, increasing the risk of further complications. This is, to our knowledge, the first case report about a PICC tip not centrally located, identified during insertion, thanks to false positive IC-ECG and TTE with delayed bubble test.

In conclusion, IC-ECG and TTE microbubble test are accurate methods, safe, easy to learn and widely applicable for central line tip position.^3,4 During IC-ECG, visualization of biphasic P wave is mandatory. When no visualized, suspicion of catheter malposition into accessories veins could be a reasonable cause. The use of subxiphoid TTE helps understand malposition when microbubbles don’t appear immediately in RA. When both methods are applied properly during insertion, they rule out the use of further radiological exams for tip location. Considering that CXR for tip identification is no more the gold standard,^1,10 PICC insertion protocols should include one or more intraprocedural methods of tip location.^2,7 The combined use of IC-ECG and the bubble are real-time intraoperative guidance for tip identification, enabling immediate adjustment and reducing the need for later catheter repositioning. They are also economical and resource-efficient methods, reducing costs, radiation and logistic delays of post-operative confirmation methods.