| 摘要 |
A syringe for collecting blood samples, especially arterial blood samples, comprises a syringe cylinder (11) and a piston assembly (12) displaceably arranged therein. The piston assembly defines a venting passage (25, 37, 31) through which gas or air may escape when arterial blood flows into the cylinder space (17) under the influence of the arterial blood pressure. The venting passage is controlled by valve means (23, 31), which may selectively and reversably be opened and closed independently of axial displacement of the piston assembly. The valve means may, for example, be operated by rotating a piston rod through a predetermined angle or by means of a valve actuating lever (35), which is biased towards a position in which the valve means are closed, and which may be tilted to an open position by depressing a finger grip (36) positioned at the free outer end of the piston rod (32). |
