Blood sampling device

Abstract

A blood sampling device is provided for mounting on a patient's forearm or other suitable body location, which incorporates an admixture reservoir and a closed blood sampling cavity in a single housing, the functional elements of which are firmly mounted and easily accessible to the caregiver. The blood sampling cavity is preferably accessed by a blunt cannula, which is readily retained in the sampling cavity by virtue of the cavity's secured position and elevated location on the sampling device housing during the sampling procedure, without the need for a cannula locking device. The sampling device of the present invention incorporates an admixture reservoir having a rotary actuator, through which the internal fluid volume of the admixture reservoir is manipulated from nil to a volume which is sufficient to remove all admixture from the blood sampling cavity during a sampling procedure, thus insuring that a clean blood sample may be withdrawn by an aspiration device attached to a sterile blunt cannula which penetrates a split septum of the blood sampling cavity. In a preferred embodiment, the internal surface of the admixture reservoir, which contacts a flexible stopper portion of the actuator, is provided with a curved shape which causes the outer edges of the flexible stopper to first contact the reservoir walls, followed subsequently by wall contact with increasingly more central interior portions of the stopper, and finally through contact and sealing of a central exit port in the reservoir, such that all admixture is urged from the walls of the reservoir as the reservoir is closed.