| 摘要 |
The blood-taking device is of the type where a hypodermic needle is inserted into a blood vessela nd one or more evacuated containers in successions are connected to the needle for collecting blood samples. The device has two valves. The first valve closes the proximal end of the needle section when a container is not connected to it and the second valve makes it possible to control the difference of pressure utilized for drawing blood from a subject. The second valve can be closed rapidly in the event it is discovered that the needle lies in tissue exterior to a blood vessel rather than in a blood vessel itself, thereby preventing extravasation and haematoma. |
