Effectiveness of subcutaneous tunneling technique in reducing PICC dislodgement and malposition: a pilot multicenter randomized controlled trial

Peripherally inserted central catheters (PICCs) are highly recommended for patients requiring chemotherapy, prolonged parenteral nutrition, and long-term antibiotic therapy due to their safety, convenience, versatility, and cost-effectiveness.^1–3 As with other central venous access devices (CVADs), there are some initial problems with PICCs. Approximately 14.4%–61.4% of catheters have complications, which increase patients’ physical burden and lead to improper treatment.^4–6

Catheter dislodgement and malposition are common and serious problems associated with long-term indwelling. A catheter moved distally is more likely to cause blockage, thrombosis, and malfunctions, whereas a catheter moved proximally is more likely to cause arrhythmias, cardiac tamponade, and tricuspid valve dysfunction.⁷ Several approaches have been made to securing PICCs, including sutureless devices, semipermeable transparent dressings, and cyanoacrylate adhesives. However, these measures are estimated to be effective between 85% and 95%, and components should be changed regularly.^8–10 A bundled approach may be optional without considering economic costs, but more randomized controlled trials (RCTs) with appropriate sample sizes are needed to confirm it.¹¹

Subcutaneous tunneling is a relatively mature technique that uses either a single puncture with the appropriate needle or a double puncture with a metallic device. As early as 2001, Selby et al.¹² first reported the subcutaneous tunneling technique for PICCs placement. After that, two Chinese scholars^13,14 independently conducted an RCT study and concluded that tunneled PICCs were more effective in preventing dislodgement and malposition than non-tunneled PICCs. However, the results of a multicenter case-control study¹⁵ showed no statistical difference between the two groups (P > 0.05).

Differences in the results may be indirectly affected by the catheter material, the number of lumens, or the securement strategies. However, it is confirmed that the catheter can move under certain circumstances, including changes in position, arm movements, changes in chest pressure, etc.^16,17 Compared to distal movement, proximal movement has received less attention, possibly due to the application of sutureless devices. Approximately 1–2 cm away from the catheter exit, this device effectively limits PICCs’ proximal movement. However, the clinical practice seems to ignore that a minor proximal movement of PICCs can introduce various bacteria into the blood vessels; distal movement may not cause serious health risks at the same distance. Therefore, a parallel, singleblinded, multicenter, and randomized controlled trial was conducted to evaluate the impact of the subcutaneous tunneling technique on catheter movement.

PICC-related complications have been compared based on the subcutaneous tunneling technique,^15,25–27 but a detailed description of catheter dislodgement and malposition is lacking. Our results showed no significant difference in the incidence of distal catheter movement between the two groups, whether it was the 2 cm or the 5 cm criteria; however, the incidence of proximal catheter movement was significantly reduced in the experimental group, which was reported for the first time. Kim et al.¹⁵ reported that this technique was ineffective in reducing distal movement, but the other two studies^13,14 reported its significance (P < 0.05). In PICCs placement, securement strategies might have contributed to this difference. In other words, the conventional group also had limited catheter movement if assisted securing was used, making it difficult to observe the difference.

Due to the pressure of tissue compression on catheter securement within the subcutaneous tunnel, tunneled PICCs were shown to minimize freedom of movement and provide fixation of the catheter position.¹³However, subcutaneous tunneling did not significantly affect the incidence of distal catheter movement. Still, as we increased the criteria from 2 cm to 5 cm, the tunneled PICCs became more advantageous (16.9% vs. 13.5%, 3.6% vs. 5.6%). We believe that there is another explanation for this result. In the formation of subcutaneous tunnels, the catheter may have slight folds or curls, and mild prolapse may occur due to the gravity of the catheter and the pulling force during maintenance. In the middle and late dwelling stages, subcutaneous tunneling became more advantageous for securing PICCs; therefore, it may be more suitable for patients with longterm PICCs needs. Furthermore, tunneled cuffed PICCs may be necessary.^28,29 It should be noted, however, that cuffed PICCs were relatively recently introduced, and the safety and efficacy of these devices cannot be compared to the currently prevalent cuffed CICCs. Hence, clinical research is still required to demonstrate their effectiveness.

In this study, the subcutaneous tunneling technique significantly reduced proximal movement (P < 0.05), and the difference between the solid and dotted distance between groups also illustrated this. A temporal turning point appeared at 60 ± 7 d after catheter placement in the control group, suggesting that this was a period when catheter proximal movement was most common, possibly due to increased arm movement after the patient was discharged from the hospital, but the exit site had not yet fully healed. We cannot also rule out the possibility that the proximal movement was caused by the weekly dressing changes performed by medical personnel. However, the results are clear: there is greater stability in the tunneled catheter since it sits tightly under the subcutaneous tissue at a longer distance from the puncture site. In addition to the securement strategy, our study also relied on adequate exposure length, which may have contributed to discovering the potential benefits of subcutaneous tunneling. It is significant because the proximal movement of the catheter allows bacteria to enter the blood vessels and even the catheter tip to enter the heart, which can result in more severe complications.

As mentioned in previous studies,^30,31 subcutaneous tunnels form a natural barrier that makes it difficult for microbes to travel retrograde along catheters, thereby reducing the incidence of CRI (P = 0.030). This study, however, suggests that there may be another explanation. We compared the results from previous studies, which showed significant differences in CRI and proximal movement incidences^15,32,33; however, there is evidence of a positive correlation between the studies, which suggests that the subcutaneous tunneling technique may reduce the incidence of infection by inhibiting proximal catheter movement.

In the experimental group, the incidence of CRT was significantly lower than in the control group (3.6% vs. 12.5%, P < 0.001), which is consistent with previous studies but may present new clinical implications.^13,14,27 There has been evidence that the CVR has an exponential rather than a proportional effect on CRT.³² In reverse taper PICCs, the catheter size increases by 2 Fr (approximately 0.67 mm), allowing for tamponade and reducing catheter movement.³³ In our study, the tunneled PICCs with a non-reverse taper design obtained a larger vessel diameter by moving the puncture site proximally and reducing the CVR. In other words, subcutaneous tunneling may be a better solution to allow for tamponade and reduce catheter movement without affecting the CVR, reducing the risk of CRT.

At present, tunneled PICCs are not popular in clinical catheterization. However, high rates of CRI and CRT are indeed significant factors affecting the acceptance and promotion of PICCs. This study supports the benefit of subcutaneous tunneling for people with indwelling PICCs in reducing CRI and CRT. Thus, subcutaneous tunneling technology should be promoted in PICCs placement, particularly in patients at high risk of thrombosis and infection. This is the first study that indicates that low CRI and CRT may be related to catheter retraction movement, which may provide a fresh perspective on tunneled PICCs. We encourage more prospective, large-sample, and multicenter studies to explore changes in the incidence of CRI and CRT based on catheter retraction movement, thereby providing more sufficient evidence to support PICC innovation.

Our study explored the effectiveness of the subcutaneous tunneling technique in reducing catheter malposition and dislodgement. This study aimed to explore whether subcutaneous tunneling reduces catheter malposition and dislodgement. Based on the results, the incidence of distal catheter movement was not significantly different between the two groups. This may indicate that cuffed PICCs or sutureless devices are still better for reducing distal catheter movement. However, proximal catheter movement was significantly decreased in the experimental group, which was reported for the first time. In addition, the incidence of CRI and CRT also decreased, possibly as a result of proximal catheter movement. Accordingly, combining subcutaneous tunneling with sutureless devices in cuffed PICCs may be advisable.

This study has several limitations. Firstly, the Infusion Therapy Standards (INS) of Practice 2021 recommend using sutureless devices to secure PICCs. Our experimental design phase did not achieve uniformity across all centers, which needs to be improved. From another perspective, our study demonstrated the necessity of sutureless devices in clinical settings, as the incidence of distal movement was higher than in other studies using sutureless devices.^13–15 In light of this, we recommend that hospitals in the same situation introduce sutureless devices as soon as possible. Secondly, catheter movement is significantly affected by insert location.^34,35 As a result of factors such as patient position, skin condition, and vascular condition, 50 (16.6%) exit sites in the experimental group and 66 (20.8%) exit sites in the control group were in the red zone, which may increase catheter dislodgement and malposition. However, the comparison between the two groups was not statistically significant (χ² = 2.665, P = 0.121) and therefore had little influence on our results. Lastly, catheters made of soft materials are likely to move, affecting experimental judgments. Unlike our study, most polyurethane catheter tunnels are created before puncture. If tunnels are created using a unified approach, it would be interesting to investigate whether catheter material influences the results.