Apparatus for peripheral vascular access
This invention provides devices and methods for insertion of a catheter into a vessel. The devices include coaxial slidably mounted needle, dilator and catheter components. The methods include piercing a vessel with the needle component, dilating the pierced hole with the dilator component, retraction of the needle component, insertion of the catheter and withdrawal of the dilator.
1. A catheter insertion assembly comprising:
a guide dilator comprising a hub at a dilator proximal end;
a rigid guide needle slidably mounted within the dilator and comprising a distal piercing end, an axial bore, and a needle proximal end; and,
an actuator capable of expanding in response to heat or moisture to urge the needle from a first position proximally relative to the dilator to a second position;
wherein, in the first position, the distal piercing end of the needle extends out from a distal end of the dilator;
wherein, in a second position, the distal piercing end of the needle is retracted within the bore of the dilator; and,
whereby contact of the actuator with a warm or aqueous fluid flowing from the needle axial bore forces the needle to slide proximally relative to the dilator.
2. The assembly of claim 1 , wherein the actuator is selected from the group consisting of: a hydrogel, a dry compressed foam, a shape-memory alloy, and a dehydrated hydrophilic polymer.
3. The assembly of claim 1 , wherein the dilator is flexible.
4. The assembly of claim 1 , further comprising a transparent chamber in fluid contact with the bore of the needle at a proximal end of the needle, whereby a fluid flowing from the bore can be observed.
5. The assembly of claim 1 , further comprising a catheter slidably mounted over an outside surface of the dilator.
6. The assembly of claim 1 , wherein the actuator comprises other than a spring.
7. The assembly of claim 1 , wherein the actuator comprises a foam or sponge.
8. The assembly of claim 1 , wherein the actuator is adapted to expand in response to contact with moisture.
9. The assembly of claim 1 , wherein most of the needle within the dilator is rigid.