ONS ONCC Chemotherapy Renewal Practice Exam

When the IV catheter is no longer delivering into a vein, fluid can escape into the surrounding tissue. This leakage into tissue is called infiltration. A common clue for infiltration is the absence of blood return at the IV site, because the catheter tip may have slipped out of the vein or the vein may be collapsed, causing the infused fluid to pool in the surrounding tissue rather than enter the bloodstream. Extravasation, on the other hand, involves leakage of a vesicant chemotherapeutic agent into tissue and carries a high risk of tissue injury. While lack of blood return can occur with extravasation, the key feature is the presence of vesicant-induced damage signs such as severe pain, swelling, redness, or blistering. In the absence of such vesicant-specific signs, the scenario is more consistent with infiltration, making it the best explanation for no blood return in this context.