| 摘要 |
Ultrasound Doppler probe (2) is placed above the vein downstream of the infusion site. Processor (4) converts the output from the probe (2) into a form that may be displayed as an image on display unit (5). It also determines whether the velocity corresponds to a flow of contrast medium along the vein. If the cannula (13) is properly sited and the contrast medium flows as desired along the vein, this will lead to an increased flow velocity in the vein. This is detected by ultrasound probe (2) and, as described above, the processor unit (4) will therefore determine that no extravasation has occurred. However, where extravasation of contrast medium occurs this results in a low or zero velocity output from the probe (2) from which the processor unit (4) determines that extravasation has occurred. It therefore immediately sends a "stop" signal to pump controller (11) which stops pump (10). |
