Long-term intravascular access catheters with reservoirs are a common requirement for cancer patients. Complications resulting from the use of these devices have been studied in several single-institution investigations, the consensus being that they are safe and have a low complication rate. However, extravasation may occur especially in obese patients due to accidental infusion of the subcutaneous tissue. To prevent this problem we describe an easy method that could be an alternative to the widely used ultrasonography-guided injection method.