| abstract |
A valved multiple sample needle assembly for use with a vacuum collection device in obtaining fluid samples, particularly from a patient. The assembly comprises a housing with a chamber therein and having first and second access openings in fluid communication with the chamber. A valve seat associated with the first access opening faces the chamber, while a needle cannula extends outwardly from the first access opening. A resilient, collapsible valve member is positioned in the chamber and normally contacts the valve seat to serve as a closed valve. This valve member is adapted to resiliently collapse and operatively break the sealing engagement with the valve seat when the pressure at the second access opening is sufficiently negative with respect to the pressure at the first access opening so that fluid can flow into the chamber and then out of the second access opening. Backflow is prevented into the first access opening, since the valve member will close should fluid flow in that direction. |