Introduction
Some practice guidelines do not recommend the use of a peripheral intravenous catheter for irritant or vesicant continuous administration to avoid vessel damage [1,2]. However, peripheral intravenous catheters are unavoidably used in some patients for drug administration because of their conditions, such as superior vena cava syndrome, coagulopathy, or compromised condition. In clinical settings, induration can be observed at the catheterization sites after anticancer drug administration even without obvious signs and symptoms of extravasation such as feelings of tingling, burning, pain, swelling, and redness at the injection site [2]. If induration is found by physicians or nurses, inserting catheter to the affected site is avoided. It can lead to catheter placement in inappropriate sites, such as the hands, near joints, or thin fragile veins [3]. These catheterization sites are reported as risk factors of extravasation. Thus, induration after anticancer drug administration is a clinical challenge for patients who must receive repetitive treatment using a peripheral intravenous catheter; induration occurrence should be prevented. It is important to know the actual condition of induration very well for safe chemotherapy treatment. Ultrasonography is used to observe the condition of the vein or surrounding tissue [4,5]. We already reported actual condition of induration through ultrasonography after obvious extravasation [6], but the onset process of induration without obvious extravasation was unclear. Here, we report time-course observation of the catheterization site from pre-catheterization to induration development through ultrasonography (Figure 1).