a thoracentesis device for removing fluid from a cavity includes a hypersensitive dual spring indication mechanism for alerting the user of any contact to internal body organs . the thoracentesis device includes a handle and an outer needle fixedly attached to the handle . the outer needle forms a sharp distal end and a spring - loaded inner needle , including a blunt tip distal end , is slidably disposed inside the conduit of the outer needle . a first spring has a first spring force that urges the inner needle into a fully extended position and a second spring has a second spring force that acts on the inner needle in opposition of the first spring force . a first and second opposite colored indicators are arranged in contact with the springs so as to alert the user to any initial contact made by the thoracentesis device .