Catheter insertion device with improved flashback response
In various embodiments, an improved catheter insertion device is described that provides an improved flashback response and use for deep vein access. In various embodiments, the improved flashback response comprises two separate and distinct flash events, the first indicating insertion of a cannula in a blood vessel, and a second indicating insertion of a catheter in the blood vessel. The two flash responses are made possible by a combination of features provided on the cannula, such as including a view window in the cannula and a flat relief portion on the outer surface of the cannula at the distal opening.
1 . A catheter insertion device, comprising:
a catheter hub including an open proximal end and a distal end having connected thereto a catheter having a distal open end, a through passageway defined by the catheter extends to an interior cavity defined in the catheter hub, the catheter having a circumferential inner wall;
a septum having a given length having a distal end and a proximal end fitted to the interior cavity of the catheter hub between the distal and proximal ends of the catheter hub;
a cannula having a beveled distal tip and a circumferential wall defining a lumen an opening at the distal tip, the cannula axially movable through the septum into the interior cavity of the catheter hub and the catheter such that the distal tip of the cannula extends beyond the distal open end of the catheter in a ready position, a fenestration at the circumferential wall of the cannula proximal the distal tip providing an aperture between the lumen and the inner circumferential wall of the catheter, the fenestration having a distal edge and a proximal edge, a distance between the distal tip of the cannula and the proximal edge of the fenestration being greater than the given length of the septum and an other distance between the distal tip of the cannula and the distal edge of the fenestration being greater than a length of the beveled distal tip and less than the given length of the septum;
a flat relief portion at the cannula extending proximally from the beveled distal tip to a distance distal of the fenestration;
wherein when the cannula is inserted into a patient and the distal tip of the cannula enters into a vein of the patient, blood flows into the lumen and through the aperture into an annular space defined between the circumferential wall of the cannula and the inner circumferential wall of the catheter to provide a first flashback response, and wherein when the catheter enters the vein, blood flows into a space between the inner diameter of the catheter and the outer diameter of the flat relief portion to provide a second flashback response.
2 . The catheter insertion device of claim 1 , wherein the fenestration is partially occluded by the septum when the opening at the distal tip of the cannula is moved to within the septum.
3 . The catheter insertion device of claim 1 , wherein the proximal edge of the fenestration is proximal the proximal end of the septum and the distal end of the fenestration is inside the septum when the opening at the distal tip of the cannula is within the septum.
4 . The catheter insertion device of claim 1 , wherein the distance between the distal tip of the cannula and the proximal edge of the fenestration is less than or equal to 150% of the given length of the septum.
5 . The catheter insertion device of claim 1 , wherein the distance between the proximal edge of the fenestration and the distal tip is about 10 mm to about 50 mm.
6 . The catheter insertion device of claim 1 , wherein the cannula comprises a bump out between the distal tip and the fenestration of the cannula.
7 . The catheter insertion device of claim 6 , wherein the bump out provides an enlarged transition between the fenestration and the distal tip of the cannula such that blood in the annular space between the circumferential wall of the cannula and the inner circumferential wall of the catheter is blocked from moving distally past the enlarged transition.
8 . The catheter insertion device of claim 1 , wherein when the cannula is moved proximally relative to the septum such that the distal tip of the cannula is proximal the distal end of the septum, a portion of the fenestration distal its proximal edge is proximal from the proximal end of the septum and another portion of the fenestration proximal its distal edge remains within the septum.