Aspiration before tissue filling with hyaluronic acid-safety enhancement by using a lidocaine-primed syringe.

Abstract

Most of the doctors would regularly aspirate the plunger of a syringe before injection to make sure that the needle would not be mis-inserted into vessels. Yet pulling the plunger back only cannot guarantee the injecting status is safe. Injecting all of the non-fluid fillers, including colloidal hyaluronic acid (HA) into the vessel may cause "No blood return while pulling back the plunger," which is defined as false-negative aspiration. In the first experiment, HA syringes were inserted into vessel simulators in vitro with standard needle sizes and residual dosages. In the second experiment, the lidocaine-primed syringe were inserted into the vessel simulator instead to observe its aspiration. There was no difference using different sizes of needles or dosages except for group 0.1 mL and the lidocaine-primed syringe. The rest of the groups need to wait more seconds to observe the blood return. The time lag does exist in every single aspiration and 88% of the blood return would happen in 10 s. We suggested that operators should aspirate regularly before giving an injection with at least 10 s of waiting or use the lidocaine-primed syringe instead. Blood returns could mostly be recognized in both ways.