There might be bubbles apear if the needle hasnt got an air tight fit to the syringe!, or that the air bubbles that are already in the oil that you cant see, they only become aparrent when you aspirate and create a vacuum in the syringe causing the bubbles to expand, but they will shrink when the plunger is pushed, like jay said aspirate nice and gentley and if you hit a vein the blood will flow very easyley in to the syringe. |