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;
a spring-loaded actuator urging the needle proximally relative to the dilator; and,
a water triggered detent positioned between the needle and dilator hub preventing the needle from sliding proximally;
wherein, in a 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,
wherein, the assembly is configured so that on contact with an aqueous fluid flowing from the needle axial bore, the detent allows the needle to slide proximally relative to the dilator in response to the urging of the actuator.
2. The assembly of claim 1 , wherein the actuator is selected from the group consisting of: a spring, a torsion bar, shape memory alloy, a thermally actuated material, a hydrophilic polymer, a spring-loaded lever, a pressurized gas, and a compressed foam.
3. The assembly of claim 1 , wherein the water triggered detent is selected from the group consisting of: a water soluble material that dissolves on contact with the fluid, a dry solid that softens when hydrated, and a frictional material that becomes slippery on contact with the fluid.
4. The assembly of claim 1 , wherein the dilator proximal hub further comprises a transversely mounted septa resiliently sealed about an outer surface of the needle; or wherein the assembly further comprises a catheter having a proximal hub and slidably mounted coaxially outside the dilator, wherein the catheter proximal hub comprises a transversely mounted septa resiliently sealed about an outer surface of the dilator.