Needle assemblies and methods
A needle assembly comprises a metal needle ( 1 ) with a hub ( 13 ) and a marker in the form of a bubble-filled plastics rod ( 2 ) inserted within the needle. The rod ( 2 ) makes the assembly more visible under ultrasound observation when confirming correct placement of the needle ( 1 ) and is subsequently removed when correct placement has been confirmed.
1. A needle assembly including a hollow metal needle, characterized in that the assembly includes a plastic sleeve removably mounted along the outside of the needle and containing a plurality of gas bubbles within the thickness of the sleeve such that the sleeve is visible under ultrasound observation and such that the ultrasound visibility of the assembly with the sleeve is greater than that of the needle alone.
2. An assembly according to claim 1 , characterized in that the gas bubbles extend along substantially the entire length of the marker.
3. An assembly according to claim 1 , characterized in that the gas bubbles extend along one or more localized regions of the marker.
4. An assembly according to claim 1 , characterized in that the sleeve can be split along its length to enable removal from the rear end of the needle.
5. A method of confirming correct placement of a metal needle in a body, characterized in that the method includes the steps of mounting a bubble-filled sleeve along the outside of the needle before or after placement, viewing the body in the location of the needle with an ultrasound instrument such that the sleeve increases the visibility of the combination of the needle and sleeve compared with the needle alone, and subsequently removing the sleeve to leave the needle in position.
6. A method according to claim 5 , characterized in that the sleeve is subsequently removed from the needle by splitting the sleeve along its length.