The role of saline flush injection rate in displacement of CT-injectable peripherally inserted central catheter tip during power injection of contrast material.

The purpose of this article is to determine the rate and the cause of displacement of CT power-injectable peripherally inserted central catheters (CT-PICCs) during contrast material and saline flush injection and to modify CT-scanning protocols to decrease the frequency of displacement. In the laboratory setting, in vitro modeling of CTPICC displacement during power injection was examined while varying the initial rate of injection of the saline flush. In the clinical setting, the CT images of all patients at a large academic hospital for one calendar year who underwent power injection of CT contrast media were reviewed for CT-PICC displacement. A retrospective comparison of the rate of displacement during the 8 months before implementing a protocol with a lower initial rate of saline flush and the rate of displacement for the 4 months after the protocol change was performed. Laboratory modeling showed dramatic movement of the CT-PICC at higher rates of saline flush. This movement was attributed to differences in viscosity between contrast media and saline. The clinical arm of the study found that 8.2% of the 243 examinations performed before implementing the new protocol resulted in displacement, in comparison with 2.2% of the 138 examinations performed afterward. This difference was considered statistically significant (p = 0.023). Initiation of saline flush at high injection rates correlates with a higher rate of CT-PICC displacement. The use of a slower initial rate of saline flush injection significantly reduces the rate of displacement.