This maneuver should be repeated several times before complete withdrawal. While redirecting the needle, a corkscrew action may be used. When blood or material appears in the hub of the needle, the aspiration should be stopped. Prior to withdrawal of the needle, negative pressure must be released to prevent suction of the material into the barrel of the syringe when the needle exits the skin. While the basic aspiration procedure is similar for deep lesions, specialized equipment for imaging, specialized needles and set-ups for aspiration, and emergency equipment for handling major complications are required.
Specific techniques are highly variable, according to personal preferences.
While this guide will not attempt to provide methodological guidelines for aspiration of deep masses, the principles of not applying negative pressure until in the mass, stopping aspiration when blood or material appears in the hub of the needle, and not maintaining negative pressure when withdrawing the needle, should be kept in mind. Preparation of Direct Smears For preparation of smears, single-end frosted slides should be utilized. Slides should be labeled with patient's full name in pencil prior to aspiration. Some author investigators recommend gently expressing a drop of aspirated fluid onto a slide, while others recommend forcefully expelling the material onto the slide. The actual method will be determined in part by the nature of the material present.