Abstract A cannula assembly (65) comprising an elongated tubular cannula body (72) having a tip section (72a) and a stylet (66) slidebly positioned within the cannula body such that one end of the stylet can extend beyond said tip section. The stylet includes a stop (66b) on its outer periphery which slides within the interior of the cannula body and limits withdrawal of the stylet when engaging an anti-backflow ring (80) in the end of the cannula body remote from the tip section (72a) to prevent leakage out of the cannula body.Preferably, the ring (80) can be forced out of the cannula body and a clamp (71) is present for limiting fluid flow into the cannula body.
A cannula assembly (65) comprising an elongated tubular cannula body (72) having a tip section (72a) and a stylet (66) slidably positioned within the cannula body such that one end of the stylet can extend beyond said tip section, characterized in that the stylet includes a stop (66b) on its outer periphery which slides within the interior of the cannula body and limits withdrawal of the stylet when engaging a seal (80) in the end of the cannula body remote from the tip section (72a) to prevent leakage out of the cannula body.
Claim 2
Dependent Claim
57 words
A cannula assembly (65) according to claim 1, characterized in that said seal is an anti-backflow ring (80) positioned in the end of the cannula body (72) remote from the tip section (72a) and forming a temporary limit for said stop (66b) when said stylet (66) is in the process of being withdrawn from the cannula body.
Claim 3
Dependent Claim
102 words
A cannula assembly (65) according to claim 2, characterized in that said stylet (66) is adapted to be fully withdrawn from said cannula body (72) including forcing said ring (80) out of the cannula body, the stylet and the cannula body having such lengths that when said stop (66b) engages the ring to temporary limiting withdrawal of the stylet, the cannula body extends beyond the one end of the stylet, means (71) being present at a location between the one end of the stylet engaging the ring and the tip of the cannula body for limiting fluid flow into the cannula body.
Claim 4
Dependent Claim
31 words
A cannula assembly (65) according to claim 3, characterized in that said means for limiting fluid flow into said cannula body (72) include a clamp (71) for squeezing the cannula body.
Claim 5
Dependent Claim
38 words
A cannula assembly (65) according to one of the preceding claims, characterized in that said end of the cannula body (72) remote from the tip section (72a) is provided with means for connecting said end to a pump.