The result of this study showed that the incidence of PICC misplacement was 7.4% under the guidance of ultrasound and IC-ECG, while reduced to 0.67% on postoperative CXR after intraoperative adjustments and subsequent IC-ECG check. Cost analysis showed that postoperative CXR was a very expensive screening test when used to eliminate PICC-related mechanical complications. Notably, all postoperative catheter misplacements occurred in the azygos vein without any serious complications, and patients had trouble getting blood return by aspiration, which can be used to determine the further use of CXR, thus further clarifying the location of the tip of the catheter.
The cost of CXR varies depending on the geographic location. In this analysis, we used our hospital's quoted cost of $12.50 per orthopantomogram. The total number of CXR performed in this study was 2,857, so the total cost was $35,712 (1.5 years), or $23,808 per year. The cost of using CXR to diagnose one case of catheter misplacement, i.e. PICC repositioning, was $1,253.
This study demonstrated that the incidence of catheter misplacement was very low and the cost of routine postoperative CXR was very high. This finding suggests that postoperative CXR has a low ability to intervene and predict PICC misplacement. IC-ECG itself is better able to avoid various catheter tip misplacements. Previous guidelines recommend postoperative CXR to determine catheter tip position, and misplaced catheter tips are usually repositioned and examined by another imaging test to reassure optimal position. This procedure may prolong the use of the catheter. In addition, possible and unnecessary radiation exposure from CXR should be considered as well.
We also determined that placement via the left arm increased the incidence of catheter misplacement, around 10 times than right-sided insertion. There are no previous studies of left or right-sided insertion for PICC misplacement. A previous study found a significantly increased risk of central venous catheter tip misplacement by left-sided insertion. Another study found that there was no significant difference in the incidence of tunneled hemodialysis catheter misplacement to the azygos vein by left- or right-sided insertion. The exact reason is unclear. Anatomically, the left innominate vein is at a higher level and closer to the junction of the SVC compared to the right innominate vein. The guidewire inserted from the left side is always in contact with the lateral wall of the SVC before it is flipped into the correct position. This appears to be the mechanism of catheter misplacement into the azygos vein.
These findings suggest that routine postoperative CXR is not necessary for routine placement. However, it still should be considered in case of a high suspicion of catheter misplacement, such as after multiple attempts of insertion, or if the insertion site is not right-sided and blood return is not normal.
This study focused on perioperative PICC placement performed under ultrasound guidance. The results of this study may not be applicable to other clinical settings, as the use of ultrasound significantly reduces the dependency on practitioner’s experience in vascular cannulation. This study was performed at an institute in a university hospital in China, where ultrasound machines are widely used, and the operators have extensive experience with ultrasound-guided cannulation. The applicability of our findings to other clinical settings or to operators with different levels of experience must be considered on an individual basis.
In our study, the intraoperative misplacement rate and the incidence of vessels with misplaced catheters were similar to other studies. Our postoperative misplacement rate was significantly decreased after intraoperative adjustments by IC-ECG, and all postoperative catheter misplacements occurred in the azygos vein with an incidence of 0.67%, marginally different from the previous studies (0.7%-3.8%)[10, 14, 15]. This indicates that IC-ECG method has little role in preventing catheter tip misplacement into the azygos vein. Even if the placement is successful, inappropriate patient movement or high intracranial pressure during severe nausea, vomiting, hiccups, and constipation may also cause misplacement . In the present study, we monitored normal blood return with aspiration catheter after IC-ECG examination during the operation, but found misplacement of the catheter tip on postoperative CXR. Besides, abnormalities were found on a repeated catheter aspiration and IC-ECG localization. Therefore, whether the catheter tip is misplaced into the azygos vein due to the patient's body position change after the placement still needs further investigation.
Recently, there has been a significant focus on the "Choosing Wisely" movement in the North American health care system, with the aim of reducing low-value and wasteful tests or procedures[17, 18]. These unnecessary tests and interventions fail to bring meaningful benefits to patients and can be potentially harmful, requiring additional effort to investigate false positives, which is a significant waste of resources for both patients and health professionals. More than 50 medical societies are involved in this movement and have compiled lists of the most commonly overused tests or procedures in various relevant clinical areas. In the present study, our findings suggested that routine CXR after the use of ultrasound and IC-ECG guided PICCs is not a wise choice and should be included in the list of unnecessary test and procedures.
However, it is difficult to make changes in clinical practice[19, 20], and there is a need of cultural awareness, physician perception, and redesign of patient care processes and related guidelines. This can be facilitated by the combination of ultrasound-guided PICC implantation, subsequent ECG localization and blood return test by catheter aspiration.
A major limitation of this study is the unavoidable information bias due to the retrospective design. To ensure that information bias was minimized, we evaluated each patient's electronic CXR film and radiologist's report to verify any mechanical PICC-related complications. We also conducted data verification by a second evaluator. The other limitation is the lack of data on the duration of each PICC placement. Moreover, the cost analysis for this study was based on cost estimates for a single CXR at our institute, which may vary at other institutions.