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In 1656, Sir Christopher Wren injected opium into the veins of dogs using a quill and bladder, making him the founder of modern IV therapy. Until the 1950s, reusable steel needles were used, but the introduction of over‐the‐needle plastic IV catheters replaced indwelling metal needles, improving operator safety and allowing more patient comfort, rapid flow, and reduced infiltration [13, 14].

Flow through the catheter is based on Poiseuille’s law, dealing with pressure and resistance. The pertinent determinants of the equation include the radius of the catheter and the catheter length. Flow is directly proportional to the radius to the fourth power (r⁴) and inversely proportional to catheter length. As such, a large gauge, short IV catheter can profoundly improve the potential flow rate over a smaller gauge, longer catheter.

Typical locations for peripheral IV access include the antecubital fossa, veins in the forearm and dorsum of the hand and foot, external jugular vein, and scalp veins.