Fluid Vessel Communication Device

Abstract

A fluid vessel insertion device ( 10 ), typically for medical use, comprises a puncture member ( 18 ) arranged for location within a sleeve ( 20 ), and a retraction mechanism ( 44, 48, 60 ) for retracting the puncture member relative to the sleeve. The puncture member ( 18 ) is retractable in use between a first condition in which an end ( 18 A) of the puncture member protrudes beyond an end ( 24 ) of the sleeve and a second condition in which the end of the puncture member is within the sleeve ( 20 ). The retraction mechanism ( 44, 48, 60 ) actuates the puncture member between the first and second conditions in response to fluid pressure at the end ( 18 A) of the puncture member. The device may be used during positioning of the sleeve in a desired fluid vessel, such as, for example, during intravenous cannulation.

1 . A fluid vessel insertion device comprising:
 a puncture member arranged for location within a sleeve, and   a retraction mechanism for actuating the puncture member relative to the sleeve in use between a first condition in which an end of the puncture member protrudes beyond an end of the sleeve, and a second condition in which the end of the puncture member is retracted within the sleeve,   wherein the retraction mechanism actuates the puncture member between the first and second conditions in response to an external fluid pressure at the end of the puncture member.   
     
     
         2 . A device according to  claim 1 , wherein the puncture member is hollow to allow fluid communication with the retraction mechanism. 
     
     
         3 . A device according to  claim 1 , wherein the device comprises a medical device and the puncture member comprises a needle. 
     
     
         4 . A device according to  claim 1 , wherein the retraction mechanism comprises a chamber. 
     
     
         5 . A device according to  claim 4 , wherein the chamber is maintained at substantially ambient pressure in an at-rest state and is arranged to trigger the retraction mechanism to actuate the puncture member into the second condition when a pressure gradient is experienced between the interior of the chamber and the external pressure at the end of the puncture member. 
     
     
         6 . A device according to  claim 5 , wherein the puncture member extends into the chamber and comprises an aperture for fluid communication with the interior of the chamber and the interior of the chamber is substantially sealed from the exterior of the device save for via the puncture member aperture. 
     
     
         7 . (canceled) 
     
     
         8 . A device according to  claim 1 , wherein the retraction mechanism triggers retraction of the puncture member automatically upon sensing a pressure at or beyond a predetermined pressure difference from ambient at the end of the puncture member. 
     
     
         9 . A device according to  claim 8 , wherein the retraction mechanism comprises a pressure sensor. 
     
     
         10 . A device according to  claim 8 , wherein the retraction mechanism comprises a chamber and a diaphragm which is actuable in response to a change in pressure within the chamber. 
     
     
         11 . A device according to  claim 1 , wherein the retraction mechanism comprises a chamber in fluid communication with the end of the puncture member and an engagement member arranged to releasably engage the puncture member dependent on the pressure within the chamber. 
     
     
         12 . A device according to  claim 11 , wherein the puncture member is biased towards the second condition and is releasably held in the first condition by the engagement member. 
     
     
         13 . A device according to  claim 12 , wherein the puncture member is biased by a spring. 
     
     
         14 . A device according to  claim 1  comprising a stop member arranged to limit travel of the puncture member by the retraction mechanism to a predetermined distance. 
     
     
         15 . A device according to  claim 1 , comprising a housing for the retraction mechanism, wherein the puncture member depends from the housing such that a first end of the puncture member is spaced from the housing and a second end of the puncture member is mounted in the housing. 
     
     
         16 . (canceled) 
     
     
         17 . A device according to  claim 8 , wherein the retraction mechanism comprises a chamber and an electronic pressure sensor within the chamber, the device further comprising a controller arranged to trigger retraction of the puncture member between the first and second conditions. 
     
     
         18 . A device according to  claim 17 , wherein the retraction mechanism comprises an electric actuator. 
     
     
         19 . A fluid vessel communication assembly comprising the device of  claim 1  and a sleeve arranged to closely surround the puncture member in the vicinity of the end thereof. 
     
     
         20 . An assembly according to  claim 19 , wherein the sleeve has an open end through which the puncture member protrudes in the first condition, the open end of the sleeve being immediately adjacent the end of the puncture member in the first condition. 
     
     
         21 . An assembly according to  claim 19 , wherein the sleeve is detachably mounted to a housing for the retraction device at a location spaced from the end of the puncture member such that the puncture member retracts relative to both the housing and sleeve during actuation between the first and second conditions. 
     
     
         22 . An assembly according to  claims 19 , wherein the sleeve comprises a cannula.